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* [glibc/azanella/bz23960] linux: Set internal DIR filepos as off64_t [BZ #23960, BZ #24050]
@ 2020-10-02 13:53 Adhemerval Zanella
  0 siblings, 0 replies; 5+ messages in thread
From: Adhemerval Zanella @ 2020-10-02 13:53 UTC (permalink / raw)
  To: glibc-cvs

https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=804c2b8a8ef1d375099e92f2422b45a8ae17d08e

commit 804c2b8a8ef1d375099e92f2422b45a8ae17d08e
Author: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Date:   Mon Apr 13 18:09:20 2020 -0300

    linux: Set internal DIR filepos as off64_t [BZ #23960, BZ #24050]
    
    It allows to obtain the expected entry offset on telldir and set
    it correctly on seekdir on platforms where long int is smaller
    than off64_t.
    
    On such cases telldir will mantain an internal list that maps the
    DIR object off64_t offsets to the returned long int (the function
    return value).  The seekdir will then set the correct offset from
    the internal list using the telldir as the list key.
    
    It also removes the overflow check on readdir and the returned value
    will be truncated by the non-LFS off_t size.  As Joseph has noted
    in BZ #23960 comment #22, d_off is an opaque value and since
    telldir/seekdir works regardless of the returned dirent d_off value.
    
    Finally it removed the requirement to check for overflow values on
    telldir (BZ #24050).
    
    Checked on x86_64-linux-gnu, i686-linux-gnu, powerpc-linux-gnu,
    and arm-linux-gnueabihf.

Diff:
---
 dirent/Makefile                     |   2 +-
 dirent/tst-seekdir2.c               | 156 ++++++++++++++++++++++++++++++++++++
 support/temp_file.c                 |  12 ++-
 support/temp_file.h                 |   7 ++
 sysdeps/unix/sysv/linux/closedir.c  |   4 +
 sysdeps/unix/sysv/linux/dirstream.h |   7 +-
 sysdeps/unix/sysv/linux/opendir.c   |   3 +
 sysdeps/unix/sysv/linux/readdir.c   |   1 +
 sysdeps/unix/sysv/linux/readdir.h   |   7 +-
 sysdeps/unix/sysv/linux/rewinddir.c |   5 ++
 sysdeps/unix/sysv/linux/seekdir.c   |  36 +++++++--
 sysdeps/unix/sysv/linux/telldir.c   |  47 ++++++++++-
 sysdeps/unix/sysv/linux/telldir.h   |  64 +++++++++++++++
 13 files changed, 333 insertions(+), 18 deletions(-)

diff --git a/dirent/Makefile b/dirent/Makefile
index e917d5ceab..f100431845 100644
--- a/dirent/Makefile
+++ b/dirent/Makefile
@@ -31,7 +31,7 @@ routines	:= opendir closedir readdir readdir_r rewinddir \
 		   scandir-cancel scandir-tail scandir64-tail
 
 tests	   := list tst-seekdir opendir-tst1 bug-readdir1 tst-fdopendir \
-	      tst-fdopendir2 tst-scandir tst-scandir64
+	      tst-fdopendir2 tst-scandir tst-scandir64 tst-seekdir2 \
 
 CFLAGS-scandir.c += $(uses-callbacks)
 CFLAGS-scandir64.c += $(uses-callbacks)
diff --git a/dirent/tst-seekdir2.c b/dirent/tst-seekdir2.c
new file mode 100644
index 0000000000..4bd2509f72
--- /dev/null
+++ b/dirent/tst-seekdir2.c
@@ -0,0 +1,156 @@
+/* Check multiple telldir and seekdir.
+   Copyright (C) 2020 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#include <dirent.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <stdio.h>
+#include <string.h>
+
+#include <support/temp_file.h>
+#include <support/support.h>
+#include <support/check.h>
+
+/* Some filesystems returns a arbitrary value for d_off direnty entry (ext4
+   for instance, where the value is an internal hash key).  The idea of
+   create a large number of file is to try trigger a overflow d_off value
+   in a entry to check if telldir/seekdir does work corretly in such
+   case.  */
+static const char *dirname;
+static const size_t nfiles = 10240;
+
+static void
+do_prepare (int argc, char *argv[])
+{
+  dirname = support_create_temp_directory ("tst-seekdir2-");
+
+  for (size_t i = 0; i < nfiles; i++)
+    {
+      int fd = create_temp_file_in_dir ("tempfile.", dirname, NULL);
+      TEST_VERIFY_EXIT (fd > 0);
+      close (fd);
+    }
+}
+#define PREPARE do_prepare
+
+/* Check for old non Large File Support (LFS).  */
+static int
+do_test_not_lfs (void)
+{
+  DIR *dirp;
+  struct dirent *dp;
+  size_t dirp_count;
+
+  dirp = opendir (dirname);
+  TEST_VERIFY_EXIT (dirp != NULL);
+
+  dirp_count = 0;
+  for (dp = readdir (dirp);
+       dp != NULL;
+       dp = readdir (dirp))
+    dirp_count++;
+
+  /* The 2 extra files are '.' and '..'.  */
+  TEST_COMPARE (dirp_count, nfiles + 2);
+
+  rewinddir (dirp);
+
+  long *tdirp = xmalloc (dirp_count * sizeof (long));
+  struct dirent *ddirp = xmalloc (dirp_count * sizeof (struct dirent));
+
+  size_t i = 0;
+  do
+    {
+      tdirp[i] = telldir (dirp);
+      dp = readdir (dirp);
+      TEST_VERIFY_EXIT (dp != NULL);
+      memcpy (&ddirp[i], dp, sizeof (struct dirent));
+    } while (++i < dirp_count);
+
+  for (i = 0; i < dirp_count - 1; i++)
+    {
+      seekdir (dirp, tdirp[i]);
+      dp = readdir (dirp);
+      TEST_COMPARE (strcmp (dp->d_name, ddirp[i].d_name), 0);
+      TEST_COMPARE (dp->d_ino, ddirp[i].d_ino);
+      TEST_COMPARE (dp->d_off, ddirp[i].d_off);
+    }
+
+  closedir (dirp);
+
+  return 0;
+}
+
+/* Same as before but with LFS support.  */
+static int
+do_test_lfs (void)
+{
+  DIR *dirp;
+  struct dirent64 *dp;
+  size_t dirp_count;
+
+  dirp = opendir (dirname);
+  TEST_VERIFY_EXIT (dirp != NULL);
+
+  dirp_count = 0;
+  for (dp = readdir64 (dirp);
+       dp != NULL;
+       dp = readdir64 (dirp))
+    dirp_count++;
+
+  /* The 2 extra files are '.' and '..'.  */
+  TEST_COMPARE (dirp_count, nfiles + 2);
+
+  rewinddir (dirp);
+
+  long *tdirp = xmalloc (dirp_count * sizeof (long));
+  struct dirent64 *ddirp = xmalloc (dirp_count * sizeof (struct dirent64));
+
+  size_t i = 0;
+  do
+    {
+      tdirp[i] = telldir (dirp);
+      dp = readdir64 (dirp);
+      TEST_VERIFY_EXIT (dp != NULL);
+      memcpy (&ddirp[i], dp, sizeof (struct dirent64));
+    } while (++i < dirp_count);
+
+  for (i = 0; i < dirp_count - 1; i++)
+    {
+      seekdir (dirp, tdirp[i]);
+      dp = readdir64 (dirp);
+      TEST_COMPARE (strcmp (dp->d_name, ddirp[i].d_name), 0);
+      TEST_COMPARE (dp->d_ino, ddirp[i].d_ino);
+      TEST_COMPARE (dp->d_off, ddirp[i].d_off);
+    }
+
+  closedir (dirp);
+
+  return 0;
+}
+
+static int
+do_test (void)
+{
+  do_test_not_lfs ();
+  do_test_lfs ();
+
+  return 0;
+}
+
+#include <support/test-driver.c>
diff --git a/support/temp_file.c b/support/temp_file.c
index 277c5e0cf1..98bd235526 100644
--- a/support/temp_file.c
+++ b/support/temp_file.c
@@ -60,14 +60,12 @@ add_temp_file (const char *name)
 }
 
 int
-create_temp_file (const char *base, char **filename)
+create_temp_file_in_dir (const char *base, const char *dir, char **filename)
 {
   char *fname;
   int fd;
 
-  fname = (char *) xmalloc (strlen (test_dir) + 1 + strlen (base)
-			    + sizeof ("XXXXXX"));
-  strcpy (stpcpy (stpcpy (stpcpy (fname, test_dir), "/"), base), "XXXXXX");
+  fname = xasprintf ("%s/%sXXXXXX", dir, base);
 
   fd = mkstemp (fname);
   if (fd == -1)
@@ -86,6 +84,12 @@ create_temp_file (const char *base, char **filename)
   return fd;
 }
 
+int
+create_temp_file (const char *base, char **filename)
+{
+  return create_temp_file_in_dir (base, test_dir, filename);
+}
+
 char *
 support_create_temp_directory (const char *base)
 {
diff --git a/support/temp_file.h b/support/temp_file.h
index 8b6303a6e4..ac61105428 100644
--- a/support/temp_file.h
+++ b/support/temp_file.h
@@ -32,6 +32,13 @@ void add_temp_file (const char *name);
    *FILENAME.  */
 int create_temp_file (const char *base, char **filename);
 
+/* Create a temporary file in directory DIR.  Return the opened file
+   descriptor on success, or -1 on failure.  Write the file name to
+   *FILENAME if FILENAME is not NULL.  In this case, the caller is
+   expected to free *FILENAME.  */
+int create_temp_file_in_dir (const char *base, const char *dir,
+			     char **filename);
+
 /* Create a temporary directory and schedule it for deletion.  BASE is
    used as a prefix for the unique directory name, which the function
    returns.  The caller should free this string.  */
diff --git a/sysdeps/unix/sysv/linux/closedir.c b/sysdeps/unix/sysv/linux/closedir.c
index ccc19eefcd..c39f58aba5 100644
--- a/sysdeps/unix/sysv/linux/closedir.c
+++ b/sysdeps/unix/sysv/linux/closedir.c
@@ -43,6 +43,10 @@ __closedir (DIR *dirp)
 
   fd = dirp->fd;
 
+#ifndef __LP64__
+  dirstream_loc_clear (&dirp->locs);
+#endif
+
 #if IS_IN (libc)
   __libc_lock_fini (dirp->lock);
 #endif
diff --git a/sysdeps/unix/sysv/linux/dirstream.h b/sysdeps/unix/sysv/linux/dirstream.h
index a3ea2b7197..664d73cd40 100644
--- a/sysdeps/unix/sysv/linux/dirstream.h
+++ b/sysdeps/unix/sysv/linux/dirstream.h
@@ -21,6 +21,7 @@
 #include <sys/types.h>
 
 #include <libc-lock.h>
+#include <telldir.h>
 
 /* Directory stream type.
 
@@ -37,10 +38,14 @@ struct __dirstream
     size_t size;		/* Total valid data in the block.  */
     size_t offset;		/* Current offset into the block.  */
 
-    off_t filepos;		/* Position of next entry to read.  */
+    off64_t filepos;		/* Position of next entry to read.  */
 
     int errcode;		/* Delayed error code.  */
 
+#ifndef __LP64__
+    struct dirstream_loc_t locs;
+#endif
+
     /* Directory block.  We must make sure that this block starts
        at an address that is aligned adequately enough to store
        dirent entries.  Using the alignment of "void *" is not
diff --git a/sysdeps/unix/sysv/linux/opendir.c b/sysdeps/unix/sysv/linux/opendir.c
index 901451361e..1620171ef1 100644
--- a/sysdeps/unix/sysv/linux/opendir.c
+++ b/sysdeps/unix/sysv/linux/opendir.c
@@ -131,6 +131,9 @@ __alloc_dir (int fd, bool close_fd, int flags, const struct stat64 *statp)
   dirp->offset = 0;
   dirp->filepos = 0;
   dirp->errcode = 0;
+#ifndef __LP64__
+  dirstream_loc_init (&dirp->locs);
+#endif
 
   return dirp;
 }
diff --git a/sysdeps/unix/sysv/linux/readdir.c b/sysdeps/unix/sysv/linux/readdir.c
index 8eab0f4c9b..010ccf0a00 100644
--- a/sysdeps/unix/sysv/linux/readdir.c
+++ b/sysdeps/unix/sysv/linux/readdir.c
@@ -17,6 +17,7 @@
    <https://www.gnu.org/licenses/>.  */
 
 #include <dirent.h>
+#include <unistd.h>
 
 #if !_DIRENT_MATCHES_DIRENT64
 #include <readdir.h>
diff --git a/sysdeps/unix/sysv/linux/readdir.h b/sysdeps/unix/sysv/linux/readdir.h
index 4dc219e220..7f6cf3783d 100644
--- a/sysdeps/unix/sysv/linux/readdir.h
+++ b/sysdeps/unix/sysv/linux/readdir.h
@@ -85,15 +85,12 @@ dirstream_ret_entry (struct __dirstream *ds)
   dp->d_ino = dp64->d_ino;
 
   dp->d_off = dp64->d_off;
-  if (dp->d_off != dp64->d_off)
-    /* Overflow.  */
-    return NULL;
 
   const size_t size_diff = (offsetof (struct dirent64, d_name)
 			    - offsetof (struct dirent, d_name));
   const size_t alignment = _Alignof (struct dirent);
-  size_t new_reclen  = (dp64->d_reclen - size_diff + alignment - 1)
-			& ~(alignment - 1);
+  size_t new_reclen = (dp64->d_reclen - size_diff + alignment - 1)
+		       & ~(alignment - 1);
   if (new_reclen > return_buffer_size)
     /* Overflow.  */
     return NULL;
diff --git a/sysdeps/unix/sysv/linux/rewinddir.c b/sysdeps/unix/sysv/linux/rewinddir.c
index 860bfda004..8db0d0be4a 100644
--- a/sysdeps/unix/sysv/linux/rewinddir.c
+++ b/sysdeps/unix/sysv/linux/rewinddir.c
@@ -33,6 +33,11 @@ __rewinddir (DIR *dirp)
   dirp->offset = 0;
   dirp->size = 0;
   dirp->errcode = 0;
+
+#ifndef __LP64__
+  dirstream_loc_clear (&dirp->locs);
+#endif
+
 #if IS_IN (libc)
   __libc_lock_unlock (dirp->lock);
 #endif
diff --git a/sysdeps/unix/sysv/linux/seekdir.c b/sysdeps/unix/sysv/linux/seekdir.c
index 3c30520928..5f39ef9eef 100644
--- a/sysdeps/unix/sysv/linux/seekdir.c
+++ b/sysdeps/unix/sysv/linux/seekdir.c
@@ -22,14 +22,40 @@
 #include <dirstream.h>
 
 /* Seek to position POS in DIRP.  */
-/* XXX should be __seekdir ? */
 void
 seekdir (DIR *dirp, long int pos)
 {
+  off64_t filepos;
+
   __libc_lock_lock (dirp->lock);
-  (void) __lseek (dirp->fd, pos, SEEK_SET);
-  dirp->size = 0;
-  dirp->offset = 0;
-  dirp->filepos = pos;
+
+#ifndef __LP64__
+  union dirstream_packed dsp;
+
+  dsp.l = pos;
+
+  if (dsp.p.is_packed == 1)
+    filepos = dsp.p.info;
+  else
+    {
+      size_t index = dsp.p.info;
+
+      if (index >= dirstream_loc_size (&dirp->locs))
+	return;
+      struct dirstream_loc *loc = dirstream_loc_at (&dirp->locs, index);
+      filepos = loc->filepos;
+    }
+#else
+  filepos = pos;
+#endif
+
+  if (dirp->filepos != filepos)
+    {
+      __lseek64 (dirp->fd, filepos, SEEK_SET);
+      dirp->filepos = filepos;
+      dirp->offset = 0;
+      dirp->size = 0;
+    }
+
   __libc_lock_unlock (dirp->lock);
 }
diff --git a/sysdeps/unix/sysv/linux/telldir.c b/sysdeps/unix/sysv/linux/telldir.c
index 57d435ed21..bb33626fa4 100644
--- a/sysdeps/unix/sysv/linux/telldir.c
+++ b/sysdeps/unix/sysv/linux/telldir.c
@@ -18,16 +18,59 @@
 #include <dirent.h>
 
 #include <dirstream.h>
+#include <telldir.h>
 
 /* Return the current position of DIRP.  */
 long int
 telldir (DIR *dirp)
 {
-  long int ret;
+#ifndef __LP64__
+  /* If the directory position fits in the packet structure returns it.
+     Otherwise, check if the position is already been recorded in the
+     dynamic array.  If not, add the new record.  */
+
+  union dirstream_packed dsp;
+  size_t i;
 
   __libc_lock_lock (dirp->lock);
-  ret = dirp->filepos;
+
+  if (dirp->filepos < (1U << 31))
+    {
+      dsp.p.is_packed = 1;
+      dsp.p.info = dirp->filepos;
+      goto out;
+    }
+
+  dsp.l = -1;
+
+  for (i = 0; i < dirstream_loc_size (&dirp->locs); i++)
+    {
+      struct dirstream_loc *loc = dirstream_loc_at (&dirp->locs, i);
+      if (loc->filepos == dirp->filepos)
+	break;
+    }
+  if (i == dirstream_loc_size (&dirp->locs))
+    {
+      dirstream_loc_add (&dirp->locs,
+	(struct dirstream_loc) { dirp->filepos });
+      if (dirstream_loc_has_failed (&dirp->locs))
+	goto out;
+    }
+
+  dsp.p.is_packed = 0;
+  /* This assignment might overflow, however most likely ENOMEM would happen
+     long before.  */
+  dsp.p.info = i;
+
+out:
   __libc_lock_unlock (dirp->lock);
 
+  return dsp.l;
+#else
+  long int ret;
+  __libc_lock_lock (dirp->lock);
+  ret = dirp->filepos;
+  __libc_lock_unlock (dirp->lock);
   return ret;
+#endif
 }
diff --git a/sysdeps/unix/sysv/linux/telldir.h b/sysdeps/unix/sysv/linux/telldir.h
new file mode 100644
index 0000000000..7c45886341
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/telldir.h
@@ -0,0 +1,64 @@
+/* Linux internal telldir definitions.
+   Copyright (C) 2020 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#ifndef _TELLDIR_H
+#define _TELLDIR_H 1
+
+#ifndef __LP64__
+
+/* On platforms where long int is smaller than off64_t this is how the
+   returned value is encoded and returned by 'telldir'.  If the directory
+   offset can be enconded in 31 bits it is returned in the 'info' member
+   with 'is_packed' set to 1.
+
+   Otherwise, the 'info' member describes an index in a dynamic array at
+   'DIR' structure.  */
+
+union dirstream_packed
+{
+  long int l;
+  struct
+  {
+    unsigned long is_packed:1;
+    unsigned long info:31;
+  } p;
+};
+
+_Static_assert (sizeof (long int) == sizeof (union dirstream_packed),
+		"sizeof (long int) != sizeof (union dirstream_packed)");
+
+/* telldir will mantain a list of offsets that describe the obtained diretory
+   position if it can fit this information in the returned 'dirstream_packed'
+   struct.  */
+
+struct dirstream_loc
+{
+  off64_t filepos;
+};
+
+# define DYNARRAY_STRUCT  dirstream_loc_t
+# define DYNARRAY_ELEMENT struct dirstream_loc
+# define DYNARRAY_PREFIX  dirstream_loc_
+# include <malloc/dynarray-skeleton.c>
+#else
+
+_Static_assert (sizeof (long int) == sizeof (off64_t),
+		"sizeof (long int) != sizeof (off64_t)");
+#endif /* __LP64__  */
+
+#endif /* _TELLDIR_H  */


^ permalink raw reply	[flat|nested] 5+ messages in thread

* [glibc/azanella/bz23960] linux: Set internal DIR filepos as off64_t [BZ #23960, BZ #24050]
@ 2020-04-17 13:23 Adhemerval Zanella
  0 siblings, 0 replies; 5+ messages in thread
From: Adhemerval Zanella @ 2020-04-17 13:23 UTC (permalink / raw)
  To: glibc-cvs

https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=09a880c8bfc45662c9a5df1fe715fcc292a81d9f

commit 09a880c8bfc45662c9a5df1fe715fcc292a81d9f
Author: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Date:   Mon Apr 13 18:09:20 2020 -0300

    linux: Set internal DIR filepos as off64_t [BZ #23960, BZ #24050]
    
    It allows to obtain the expected entry offset on telldir and set
    it correctly on seekdir on platforms where long int is smaller
    than off64_t.
    
    On such cases telldir will mantain an internal list that maps the
    DIR object off64_t offsets to the returned long int (the function
    return value).  The seekdir will then set the correct offset from
    the internal list using the telldir as the list key.
    
    It also removes the overflow check on readdir and the returned value
    will be truncated by the non-LFS off_t size.  As Joseph has noted
    in BZ #23960 comment #22, d_off is an opaque value and since
    telldir/seekdir works regardless of the returned dirent d_off value.
    
    Finally it removed the requirement to check for overflow values on
    telldir (BZ #24050).
    
    Checked on x86_64-linux-gnu, i686-linux-gnu, powerpc-linux-gnu,
    and arm-linux-gnueabihf.

Diff:
---
 dirent/Makefile                     |   2 +-
 dirent/tst-seekdir2.c               | 156 ++++++++++++++++++++++++++++++++++++
 support/temp_file.c                 |  12 ++-
 support/temp_file.h                 |   7 ++
 sysdeps/unix/sysv/linux/closedir.c  |   4 +
 sysdeps/unix/sysv/linux/dirstream.h |   7 +-
 sysdeps/unix/sysv/linux/opendir.c   |   3 +
 sysdeps/unix/sysv/linux/readdir.c   |   1 +
 sysdeps/unix/sysv/linux/readdir.h   |   7 +-
 sysdeps/unix/sysv/linux/rewinddir.c |   5 ++
 sysdeps/unix/sysv/linux/seekdir.c   |  36 +++++++--
 sysdeps/unix/sysv/linux/telldir.c   |  47 ++++++++++-
 sysdeps/unix/sysv/linux/telldir.h   |  64 +++++++++++++++
 13 files changed, 333 insertions(+), 18 deletions(-)

diff --git a/dirent/Makefile b/dirent/Makefile
index e917d5ceab..f100431845 100644
--- a/dirent/Makefile
+++ b/dirent/Makefile
@@ -31,7 +31,7 @@ routines	:= opendir closedir readdir readdir_r rewinddir \
 		   scandir-cancel scandir-tail scandir64-tail
 
 tests	   := list tst-seekdir opendir-tst1 bug-readdir1 tst-fdopendir \
-	      tst-fdopendir2 tst-scandir tst-scandir64
+	      tst-fdopendir2 tst-scandir tst-scandir64 tst-seekdir2 \
 
 CFLAGS-scandir.c += $(uses-callbacks)
 CFLAGS-scandir64.c += $(uses-callbacks)
diff --git a/dirent/tst-seekdir2.c b/dirent/tst-seekdir2.c
new file mode 100644
index 0000000000..4bd2509f72
--- /dev/null
+++ b/dirent/tst-seekdir2.c
@@ -0,0 +1,156 @@
+/* Check multiple telldir and seekdir.
+   Copyright (C) 2020 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#include <dirent.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <stdio.h>
+#include <string.h>
+
+#include <support/temp_file.h>
+#include <support/support.h>
+#include <support/check.h>
+
+/* Some filesystems returns a arbitrary value for d_off direnty entry (ext4
+   for instance, where the value is an internal hash key).  The idea of
+   create a large number of file is to try trigger a overflow d_off value
+   in a entry to check if telldir/seekdir does work corretly in such
+   case.  */
+static const char *dirname;
+static const size_t nfiles = 10240;
+
+static void
+do_prepare (int argc, char *argv[])
+{
+  dirname = support_create_temp_directory ("tst-seekdir2-");
+
+  for (size_t i = 0; i < nfiles; i++)
+    {
+      int fd = create_temp_file_in_dir ("tempfile.", dirname, NULL);
+      TEST_VERIFY_EXIT (fd > 0);
+      close (fd);
+    }
+}
+#define PREPARE do_prepare
+
+/* Check for old non Large File Support (LFS).  */
+static int
+do_test_not_lfs (void)
+{
+  DIR *dirp;
+  struct dirent *dp;
+  size_t dirp_count;
+
+  dirp = opendir (dirname);
+  TEST_VERIFY_EXIT (dirp != NULL);
+
+  dirp_count = 0;
+  for (dp = readdir (dirp);
+       dp != NULL;
+       dp = readdir (dirp))
+    dirp_count++;
+
+  /* The 2 extra files are '.' and '..'.  */
+  TEST_COMPARE (dirp_count, nfiles + 2);
+
+  rewinddir (dirp);
+
+  long *tdirp = xmalloc (dirp_count * sizeof (long));
+  struct dirent *ddirp = xmalloc (dirp_count * sizeof (struct dirent));
+
+  size_t i = 0;
+  do
+    {
+      tdirp[i] = telldir (dirp);
+      dp = readdir (dirp);
+      TEST_VERIFY_EXIT (dp != NULL);
+      memcpy (&ddirp[i], dp, sizeof (struct dirent));
+    } while (++i < dirp_count);
+
+  for (i = 0; i < dirp_count - 1; i++)
+    {
+      seekdir (dirp, tdirp[i]);
+      dp = readdir (dirp);
+      TEST_COMPARE (strcmp (dp->d_name, ddirp[i].d_name), 0);
+      TEST_COMPARE (dp->d_ino, ddirp[i].d_ino);
+      TEST_COMPARE (dp->d_off, ddirp[i].d_off);
+    }
+
+  closedir (dirp);
+
+  return 0;
+}
+
+/* Same as before but with LFS support.  */
+static int
+do_test_lfs (void)
+{
+  DIR *dirp;
+  struct dirent64 *dp;
+  size_t dirp_count;
+
+  dirp = opendir (dirname);
+  TEST_VERIFY_EXIT (dirp != NULL);
+
+  dirp_count = 0;
+  for (dp = readdir64 (dirp);
+       dp != NULL;
+       dp = readdir64 (dirp))
+    dirp_count++;
+
+  /* The 2 extra files are '.' and '..'.  */
+  TEST_COMPARE (dirp_count, nfiles + 2);
+
+  rewinddir (dirp);
+
+  long *tdirp = xmalloc (dirp_count * sizeof (long));
+  struct dirent64 *ddirp = xmalloc (dirp_count * sizeof (struct dirent64));
+
+  size_t i = 0;
+  do
+    {
+      tdirp[i] = telldir (dirp);
+      dp = readdir64 (dirp);
+      TEST_VERIFY_EXIT (dp != NULL);
+      memcpy (&ddirp[i], dp, sizeof (struct dirent64));
+    } while (++i < dirp_count);
+
+  for (i = 0; i < dirp_count - 1; i++)
+    {
+      seekdir (dirp, tdirp[i]);
+      dp = readdir64 (dirp);
+      TEST_COMPARE (strcmp (dp->d_name, ddirp[i].d_name), 0);
+      TEST_COMPARE (dp->d_ino, ddirp[i].d_ino);
+      TEST_COMPARE (dp->d_off, ddirp[i].d_off);
+    }
+
+  closedir (dirp);
+
+  return 0;
+}
+
+static int
+do_test (void)
+{
+  do_test_not_lfs ();
+  do_test_lfs ();
+
+  return 0;
+}
+
+#include <support/test-driver.c>
diff --git a/support/temp_file.c b/support/temp_file.c
index 277c5e0cf1..98bd235526 100644
--- a/support/temp_file.c
+++ b/support/temp_file.c
@@ -60,14 +60,12 @@ add_temp_file (const char *name)
 }
 
 int
-create_temp_file (const char *base, char **filename)
+create_temp_file_in_dir (const char *base, const char *dir, char **filename)
 {
   char *fname;
   int fd;
 
-  fname = (char *) xmalloc (strlen (test_dir) + 1 + strlen (base)
-			    + sizeof ("XXXXXX"));
-  strcpy (stpcpy (stpcpy (stpcpy (fname, test_dir), "/"), base), "XXXXXX");
+  fname = xasprintf ("%s/%sXXXXXX", dir, base);
 
   fd = mkstemp (fname);
   if (fd == -1)
@@ -86,6 +84,12 @@ create_temp_file (const char *base, char **filename)
   return fd;
 }
 
+int
+create_temp_file (const char *base, char **filename)
+{
+  return create_temp_file_in_dir (base, test_dir, filename);
+}
+
 char *
 support_create_temp_directory (const char *base)
 {
diff --git a/support/temp_file.h b/support/temp_file.h
index 8b6303a6e4..ac61105428 100644
--- a/support/temp_file.h
+++ b/support/temp_file.h
@@ -32,6 +32,13 @@ void add_temp_file (const char *name);
    *FILENAME.  */
 int create_temp_file (const char *base, char **filename);
 
+/* Create a temporary file in directory DIR.  Return the opened file
+   descriptor on success, or -1 on failure.  Write the file name to
+   *FILENAME if FILENAME is not NULL.  In this case, the caller is
+   expected to free *FILENAME.  */
+int create_temp_file_in_dir (const char *base, const char *dir,
+			     char **filename);
+
 /* Create a temporary directory and schedule it for deletion.  BASE is
    used as a prefix for the unique directory name, which the function
    returns.  The caller should free this string.  */
diff --git a/sysdeps/unix/sysv/linux/closedir.c b/sysdeps/unix/sysv/linux/closedir.c
index ccc19eefcd..c39f58aba5 100644
--- a/sysdeps/unix/sysv/linux/closedir.c
+++ b/sysdeps/unix/sysv/linux/closedir.c
@@ -43,6 +43,10 @@ __closedir (DIR *dirp)
 
   fd = dirp->fd;
 
+#ifndef __LP64__
+  dirstream_loc_clear (&dirp->locs);
+#endif
+
 #if IS_IN (libc)
   __libc_lock_fini (dirp->lock);
 #endif
diff --git a/sysdeps/unix/sysv/linux/dirstream.h b/sysdeps/unix/sysv/linux/dirstream.h
index a3ea2b7197..664d73cd40 100644
--- a/sysdeps/unix/sysv/linux/dirstream.h
+++ b/sysdeps/unix/sysv/linux/dirstream.h
@@ -21,6 +21,7 @@
 #include <sys/types.h>
 
 #include <libc-lock.h>
+#include <telldir.h>
 
 /* Directory stream type.
 
@@ -37,10 +38,14 @@ struct __dirstream
     size_t size;		/* Total valid data in the block.  */
     size_t offset;		/* Current offset into the block.  */
 
-    off_t filepos;		/* Position of next entry to read.  */
+    off64_t filepos;		/* Position of next entry to read.  */
 
     int errcode;		/* Delayed error code.  */
 
+#ifndef __LP64__
+    struct dirstream_loc_t locs;
+#endif
+
     /* Directory block.  We must make sure that this block starts
        at an address that is aligned adequately enough to store
        dirent entries.  Using the alignment of "void *" is not
diff --git a/sysdeps/unix/sysv/linux/opendir.c b/sysdeps/unix/sysv/linux/opendir.c
index d4a0885bd3..a987af0e89 100644
--- a/sysdeps/unix/sysv/linux/opendir.c
+++ b/sysdeps/unix/sysv/linux/opendir.c
@@ -131,6 +131,9 @@ __alloc_dir (int fd, bool close_fd, int flags, const struct stat64 *statp)
   dirp->offset = 0;
   dirp->filepos = 0;
   dirp->errcode = 0;
+#ifndef __LP64__
+  dirstream_loc_init (&dirp->locs);
+#endif
 
   return dirp;
 }
diff --git a/sysdeps/unix/sysv/linux/readdir.c b/sysdeps/unix/sysv/linux/readdir.c
index 8eab0f4c9b..010ccf0a00 100644
--- a/sysdeps/unix/sysv/linux/readdir.c
+++ b/sysdeps/unix/sysv/linux/readdir.c
@@ -17,6 +17,7 @@
    <https://www.gnu.org/licenses/>.  */
 
 #include <dirent.h>
+#include <unistd.h>
 
 #if !_DIRENT_MATCHES_DIRENT64
 #include <readdir.h>
diff --git a/sysdeps/unix/sysv/linux/readdir.h b/sysdeps/unix/sysv/linux/readdir.h
index 4dc219e220..7f6cf3783d 100644
--- a/sysdeps/unix/sysv/linux/readdir.h
+++ b/sysdeps/unix/sysv/linux/readdir.h
@@ -85,15 +85,12 @@ dirstream_ret_entry (struct __dirstream *ds)
   dp->d_ino = dp64->d_ino;
 
   dp->d_off = dp64->d_off;
-  if (dp->d_off != dp64->d_off)
-    /* Overflow.  */
-    return NULL;
 
   const size_t size_diff = (offsetof (struct dirent64, d_name)
 			    - offsetof (struct dirent, d_name));
   const size_t alignment = _Alignof (struct dirent);
-  size_t new_reclen  = (dp64->d_reclen - size_diff + alignment - 1)
-			& ~(alignment - 1);
+  size_t new_reclen = (dp64->d_reclen - size_diff + alignment - 1)
+		       & ~(alignment - 1);
   if (new_reclen > return_buffer_size)
     /* Overflow.  */
     return NULL;
diff --git a/sysdeps/unix/sysv/linux/rewinddir.c b/sysdeps/unix/sysv/linux/rewinddir.c
index 860bfda004..8db0d0be4a 100644
--- a/sysdeps/unix/sysv/linux/rewinddir.c
+++ b/sysdeps/unix/sysv/linux/rewinddir.c
@@ -33,6 +33,11 @@ __rewinddir (DIR *dirp)
   dirp->offset = 0;
   dirp->size = 0;
   dirp->errcode = 0;
+
+#ifndef __LP64__
+  dirstream_loc_clear (&dirp->locs);
+#endif
+
 #if IS_IN (libc)
   __libc_lock_unlock (dirp->lock);
 #endif
diff --git a/sysdeps/unix/sysv/linux/seekdir.c b/sysdeps/unix/sysv/linux/seekdir.c
index 3c30520928..5f39ef9eef 100644
--- a/sysdeps/unix/sysv/linux/seekdir.c
+++ b/sysdeps/unix/sysv/linux/seekdir.c
@@ -22,14 +22,40 @@
 #include <dirstream.h>
 
 /* Seek to position POS in DIRP.  */
-/* XXX should be __seekdir ? */
 void
 seekdir (DIR *dirp, long int pos)
 {
+  off64_t filepos;
+
   __libc_lock_lock (dirp->lock);
-  (void) __lseek (dirp->fd, pos, SEEK_SET);
-  dirp->size = 0;
-  dirp->offset = 0;
-  dirp->filepos = pos;
+
+#ifndef __LP64__
+  union dirstream_packed dsp;
+
+  dsp.l = pos;
+
+  if (dsp.p.is_packed == 1)
+    filepos = dsp.p.info;
+  else
+    {
+      size_t index = dsp.p.info;
+
+      if (index >= dirstream_loc_size (&dirp->locs))
+	return;
+      struct dirstream_loc *loc = dirstream_loc_at (&dirp->locs, index);
+      filepos = loc->filepos;
+    }
+#else
+  filepos = pos;
+#endif
+
+  if (dirp->filepos != filepos)
+    {
+      __lseek64 (dirp->fd, filepos, SEEK_SET);
+      dirp->filepos = filepos;
+      dirp->offset = 0;
+      dirp->size = 0;
+    }
+
   __libc_lock_unlock (dirp->lock);
 }
diff --git a/sysdeps/unix/sysv/linux/telldir.c b/sysdeps/unix/sysv/linux/telldir.c
index 57d435ed21..bb33626fa4 100644
--- a/sysdeps/unix/sysv/linux/telldir.c
+++ b/sysdeps/unix/sysv/linux/telldir.c
@@ -18,16 +18,59 @@
 #include <dirent.h>
 
 #include <dirstream.h>
+#include <telldir.h>
 
 /* Return the current position of DIRP.  */
 long int
 telldir (DIR *dirp)
 {
-  long int ret;
+#ifndef __LP64__
+  /* If the directory position fits in the packet structure returns it.
+     Otherwise, check if the position is already been recorded in the
+     dynamic array.  If not, add the new record.  */
+
+  union dirstream_packed dsp;
+  size_t i;
 
   __libc_lock_lock (dirp->lock);
-  ret = dirp->filepos;
+
+  if (dirp->filepos < (1U << 31))
+    {
+      dsp.p.is_packed = 1;
+      dsp.p.info = dirp->filepos;
+      goto out;
+    }
+
+  dsp.l = -1;
+
+  for (i = 0; i < dirstream_loc_size (&dirp->locs); i++)
+    {
+      struct dirstream_loc *loc = dirstream_loc_at (&dirp->locs, i);
+      if (loc->filepos == dirp->filepos)
+	break;
+    }
+  if (i == dirstream_loc_size (&dirp->locs))
+    {
+      dirstream_loc_add (&dirp->locs,
+	(struct dirstream_loc) { dirp->filepos });
+      if (dirstream_loc_has_failed (&dirp->locs))
+	goto out;
+    }
+
+  dsp.p.is_packed = 0;
+  /* This assignment might overflow, however most likely ENOMEM would happen
+     long before.  */
+  dsp.p.info = i;
+
+out:
   __libc_lock_unlock (dirp->lock);
 
+  return dsp.l;
+#else
+  long int ret;
+  __libc_lock_lock (dirp->lock);
+  ret = dirp->filepos;
+  __libc_lock_unlock (dirp->lock);
   return ret;
+#endif
 }
diff --git a/sysdeps/unix/sysv/linux/telldir.h b/sysdeps/unix/sysv/linux/telldir.h
new file mode 100644
index 0000000000..7c45886341
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/telldir.h
@@ -0,0 +1,64 @@
+/* Linux internal telldir definitions.
+   Copyright (C) 2020 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#ifndef _TELLDIR_H
+#define _TELLDIR_H 1
+
+#ifndef __LP64__
+
+/* On platforms where long int is smaller than off64_t this is how the
+   returned value is encoded and returned by 'telldir'.  If the directory
+   offset can be enconded in 31 bits it is returned in the 'info' member
+   with 'is_packed' set to 1.
+
+   Otherwise, the 'info' member describes an index in a dynamic array at
+   'DIR' structure.  */
+
+union dirstream_packed
+{
+  long int l;
+  struct
+  {
+    unsigned long is_packed:1;
+    unsigned long info:31;
+  } p;
+};
+
+_Static_assert (sizeof (long int) == sizeof (union dirstream_packed),
+		"sizeof (long int) != sizeof (union dirstream_packed)");
+
+/* telldir will mantain a list of offsets that describe the obtained diretory
+   position if it can fit this information in the returned 'dirstream_packed'
+   struct.  */
+
+struct dirstream_loc
+{
+  off64_t filepos;
+};
+
+# define DYNARRAY_STRUCT  dirstream_loc_t
+# define DYNARRAY_ELEMENT struct dirstream_loc
+# define DYNARRAY_PREFIX  dirstream_loc_
+# include <malloc/dynarray-skeleton.c>
+#else
+
+_Static_assert (sizeof (long int) == sizeof (off64_t),
+		"sizeof (long int) != sizeof (off64_t)");
+#endif /* __LP64__  */
+
+#endif /* _TELLDIR_H  */


^ permalink raw reply	[flat|nested] 5+ messages in thread

* [glibc/azanella/bz23960] linux: Set internal DIR filepos as off64_t [BZ #23960, BZ #24050]
@ 2020-04-16 13:21 Adhemerval Zanella
  0 siblings, 0 replies; 5+ messages in thread
From: Adhemerval Zanella @ 2020-04-16 13:21 UTC (permalink / raw)
  To: glibc-cvs

https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=7c4f353cd915ff1c760d57108f078b76abcb2d8c

commit 7c4f353cd915ff1c760d57108f078b76abcb2d8c
Author: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Date:   Mon Apr 13 18:09:20 2020 -0300

    linux: Set internal DIR filepos as off64_t [BZ #23960, BZ #24050]
    
    It allows to obtain the expected entry offset on telldir and set
    it correctly on seekdir on platforms where long int is smaller
    than off64_t.
    
    On such cases telldir will mantain an internal list that maps the
    DIR object off64_t offsets to the returned long int (the function
    return value).  The seekdir will then set the correct offset from
    the internal list using the telldir as the list key.
    
    It also removes the overflow check on readdir and the returned value
    will be truncated by the non-LFS off_t size.  As Joseph has noted
    in BZ #23960 comment #22, d_off is an opaque value and since
    telldir/seekdir works regardless of the returned dirent d_off value.
    
    Finally it removed the requirement to check for overflow values on
    telldir (BZ #24050).
    
    Checked on i686-linux-gnu and x86_64-linux-gnu.

Diff:
---
 dirent/Makefile                     |   2 +-
 dirent/tst-seekdir2.c               | 156 ++++++++++++++++++++++++++++++++++++
 support/temp_file.c                 |  12 ++-
 support/temp_file.h                 |   7 ++
 sysdeps/unix/sysv/linux/closedir.c  |   4 +
 sysdeps/unix/sysv/linux/dirstream.h |   7 +-
 sysdeps/unix/sysv/linux/opendir.c   |   3 +
 sysdeps/unix/sysv/linux/readdir.c   |   1 +
 sysdeps/unix/sysv/linux/readdir.h   |   7 +-
 sysdeps/unix/sysv/linux/rewinddir.c |   5 ++
 sysdeps/unix/sysv/linux/seekdir.c   |  36 +++++++--
 sysdeps/unix/sysv/linux/telldir.c   |  47 ++++++++++-
 sysdeps/unix/sysv/linux/telldir.h   |  64 +++++++++++++++
 13 files changed, 333 insertions(+), 18 deletions(-)

diff --git a/dirent/Makefile b/dirent/Makefile
index e917d5ceab..f100431845 100644
--- a/dirent/Makefile
+++ b/dirent/Makefile
@@ -31,7 +31,7 @@ routines	:= opendir closedir readdir readdir_r rewinddir \
 		   scandir-cancel scandir-tail scandir64-tail
 
 tests	   := list tst-seekdir opendir-tst1 bug-readdir1 tst-fdopendir \
-	      tst-fdopendir2 tst-scandir tst-scandir64
+	      tst-fdopendir2 tst-scandir tst-scandir64 tst-seekdir2 \
 
 CFLAGS-scandir.c += $(uses-callbacks)
 CFLAGS-scandir64.c += $(uses-callbacks)
diff --git a/dirent/tst-seekdir2.c b/dirent/tst-seekdir2.c
new file mode 100644
index 0000000000..4bd2509f72
--- /dev/null
+++ b/dirent/tst-seekdir2.c
@@ -0,0 +1,156 @@
+/* Check multiple telldir and seekdir.
+   Copyright (C) 2020 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#include <dirent.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <stdio.h>
+#include <string.h>
+
+#include <support/temp_file.h>
+#include <support/support.h>
+#include <support/check.h>
+
+/* Some filesystems returns a arbitrary value for d_off direnty entry (ext4
+   for instance, where the value is an internal hash key).  The idea of
+   create a large number of file is to try trigger a overflow d_off value
+   in a entry to check if telldir/seekdir does work corretly in such
+   case.  */
+static const char *dirname;
+static const size_t nfiles = 10240;
+
+static void
+do_prepare (int argc, char *argv[])
+{
+  dirname = support_create_temp_directory ("tst-seekdir2-");
+
+  for (size_t i = 0; i < nfiles; i++)
+    {
+      int fd = create_temp_file_in_dir ("tempfile.", dirname, NULL);
+      TEST_VERIFY_EXIT (fd > 0);
+      close (fd);
+    }
+}
+#define PREPARE do_prepare
+
+/* Check for old non Large File Support (LFS).  */
+static int
+do_test_not_lfs (void)
+{
+  DIR *dirp;
+  struct dirent *dp;
+  size_t dirp_count;
+
+  dirp = opendir (dirname);
+  TEST_VERIFY_EXIT (dirp != NULL);
+
+  dirp_count = 0;
+  for (dp = readdir (dirp);
+       dp != NULL;
+       dp = readdir (dirp))
+    dirp_count++;
+
+  /* The 2 extra files are '.' and '..'.  */
+  TEST_COMPARE (dirp_count, nfiles + 2);
+
+  rewinddir (dirp);
+
+  long *tdirp = xmalloc (dirp_count * sizeof (long));
+  struct dirent *ddirp = xmalloc (dirp_count * sizeof (struct dirent));
+
+  size_t i = 0;
+  do
+    {
+      tdirp[i] = telldir (dirp);
+      dp = readdir (dirp);
+      TEST_VERIFY_EXIT (dp != NULL);
+      memcpy (&ddirp[i], dp, sizeof (struct dirent));
+    } while (++i < dirp_count);
+
+  for (i = 0; i < dirp_count - 1; i++)
+    {
+      seekdir (dirp, tdirp[i]);
+      dp = readdir (dirp);
+      TEST_COMPARE (strcmp (dp->d_name, ddirp[i].d_name), 0);
+      TEST_COMPARE (dp->d_ino, ddirp[i].d_ino);
+      TEST_COMPARE (dp->d_off, ddirp[i].d_off);
+    }
+
+  closedir (dirp);
+
+  return 0;
+}
+
+/* Same as before but with LFS support.  */
+static int
+do_test_lfs (void)
+{
+  DIR *dirp;
+  struct dirent64 *dp;
+  size_t dirp_count;
+
+  dirp = opendir (dirname);
+  TEST_VERIFY_EXIT (dirp != NULL);
+
+  dirp_count = 0;
+  for (dp = readdir64 (dirp);
+       dp != NULL;
+       dp = readdir64 (dirp))
+    dirp_count++;
+
+  /* The 2 extra files are '.' and '..'.  */
+  TEST_COMPARE (dirp_count, nfiles + 2);
+
+  rewinddir (dirp);
+
+  long *tdirp = xmalloc (dirp_count * sizeof (long));
+  struct dirent64 *ddirp = xmalloc (dirp_count * sizeof (struct dirent64));
+
+  size_t i = 0;
+  do
+    {
+      tdirp[i] = telldir (dirp);
+      dp = readdir64 (dirp);
+      TEST_VERIFY_EXIT (dp != NULL);
+      memcpy (&ddirp[i], dp, sizeof (struct dirent64));
+    } while (++i < dirp_count);
+
+  for (i = 0; i < dirp_count - 1; i++)
+    {
+      seekdir (dirp, tdirp[i]);
+      dp = readdir64 (dirp);
+      TEST_COMPARE (strcmp (dp->d_name, ddirp[i].d_name), 0);
+      TEST_COMPARE (dp->d_ino, ddirp[i].d_ino);
+      TEST_COMPARE (dp->d_off, ddirp[i].d_off);
+    }
+
+  closedir (dirp);
+
+  return 0;
+}
+
+static int
+do_test (void)
+{
+  do_test_not_lfs ();
+  do_test_lfs ();
+
+  return 0;
+}
+
+#include <support/test-driver.c>
diff --git a/support/temp_file.c b/support/temp_file.c
index 277c5e0cf1..98bd235526 100644
--- a/support/temp_file.c
+++ b/support/temp_file.c
@@ -60,14 +60,12 @@ add_temp_file (const char *name)
 }
 
 int
-create_temp_file (const char *base, char **filename)
+create_temp_file_in_dir (const char *base, const char *dir, char **filename)
 {
   char *fname;
   int fd;
 
-  fname = (char *) xmalloc (strlen (test_dir) + 1 + strlen (base)
-			    + sizeof ("XXXXXX"));
-  strcpy (stpcpy (stpcpy (stpcpy (fname, test_dir), "/"), base), "XXXXXX");
+  fname = xasprintf ("%s/%sXXXXXX", dir, base);
 
   fd = mkstemp (fname);
   if (fd == -1)
@@ -86,6 +84,12 @@ create_temp_file (const char *base, char **filename)
   return fd;
 }
 
+int
+create_temp_file (const char *base, char **filename)
+{
+  return create_temp_file_in_dir (base, test_dir, filename);
+}
+
 char *
 support_create_temp_directory (const char *base)
 {
diff --git a/support/temp_file.h b/support/temp_file.h
index 8b6303a6e4..ac61105428 100644
--- a/support/temp_file.h
+++ b/support/temp_file.h
@@ -32,6 +32,13 @@ void add_temp_file (const char *name);
    *FILENAME.  */
 int create_temp_file (const char *base, char **filename);
 
+/* Create a temporary file in directory DIR.  Return the opened file
+   descriptor on success, or -1 on failure.  Write the file name to
+   *FILENAME if FILENAME is not NULL.  In this case, the caller is
+   expected to free *FILENAME.  */
+int create_temp_file_in_dir (const char *base, const char *dir,
+			     char **filename);
+
 /* Create a temporary directory and schedule it for deletion.  BASE is
    used as a prefix for the unique directory name, which the function
    returns.  The caller should free this string.  */
diff --git a/sysdeps/unix/sysv/linux/closedir.c b/sysdeps/unix/sysv/linux/closedir.c
index ccc19eefcd..c39f58aba5 100644
--- a/sysdeps/unix/sysv/linux/closedir.c
+++ b/sysdeps/unix/sysv/linux/closedir.c
@@ -43,6 +43,10 @@ __closedir (DIR *dirp)
 
   fd = dirp->fd;
 
+#ifndef __LP64__
+  dirstream_loc_clear (&dirp->locs);
+#endif
+
 #if IS_IN (libc)
   __libc_lock_fini (dirp->lock);
 #endif
diff --git a/sysdeps/unix/sysv/linux/dirstream.h b/sysdeps/unix/sysv/linux/dirstream.h
index a3ea2b7197..664d73cd40 100644
--- a/sysdeps/unix/sysv/linux/dirstream.h
+++ b/sysdeps/unix/sysv/linux/dirstream.h
@@ -21,6 +21,7 @@
 #include <sys/types.h>
 
 #include <libc-lock.h>
+#include <telldir.h>
 
 /* Directory stream type.
 
@@ -37,10 +38,14 @@ struct __dirstream
     size_t size;		/* Total valid data in the block.  */
     size_t offset;		/* Current offset into the block.  */
 
-    off_t filepos;		/* Position of next entry to read.  */
+    off64_t filepos;		/* Position of next entry to read.  */
 
     int errcode;		/* Delayed error code.  */
 
+#ifndef __LP64__
+    struct dirstream_loc_t locs;
+#endif
+
     /* Directory block.  We must make sure that this block starts
        at an address that is aligned adequately enough to store
        dirent entries.  Using the alignment of "void *" is not
diff --git a/sysdeps/unix/sysv/linux/opendir.c b/sysdeps/unix/sysv/linux/opendir.c
index d4a0885bd3..a987af0e89 100644
--- a/sysdeps/unix/sysv/linux/opendir.c
+++ b/sysdeps/unix/sysv/linux/opendir.c
@@ -131,6 +131,9 @@ __alloc_dir (int fd, bool close_fd, int flags, const struct stat64 *statp)
   dirp->offset = 0;
   dirp->filepos = 0;
   dirp->errcode = 0;
+#ifndef __LP64__
+  dirstream_loc_init (&dirp->locs);
+#endif
 
   return dirp;
 }
diff --git a/sysdeps/unix/sysv/linux/readdir.c b/sysdeps/unix/sysv/linux/readdir.c
index 8eab0f4c9b..010ccf0a00 100644
--- a/sysdeps/unix/sysv/linux/readdir.c
+++ b/sysdeps/unix/sysv/linux/readdir.c
@@ -17,6 +17,7 @@
    <https://www.gnu.org/licenses/>.  */
 
 #include <dirent.h>
+#include <unistd.h>
 
 #if !_DIRENT_MATCHES_DIRENT64
 #include <readdir.h>
diff --git a/sysdeps/unix/sysv/linux/readdir.h b/sysdeps/unix/sysv/linux/readdir.h
index 4dc219e220..7f6cf3783d 100644
--- a/sysdeps/unix/sysv/linux/readdir.h
+++ b/sysdeps/unix/sysv/linux/readdir.h
@@ -85,15 +85,12 @@ dirstream_ret_entry (struct __dirstream *ds)
   dp->d_ino = dp64->d_ino;
 
   dp->d_off = dp64->d_off;
-  if (dp->d_off != dp64->d_off)
-    /* Overflow.  */
-    return NULL;
 
   const size_t size_diff = (offsetof (struct dirent64, d_name)
 			    - offsetof (struct dirent, d_name));
   const size_t alignment = _Alignof (struct dirent);
-  size_t new_reclen  = (dp64->d_reclen - size_diff + alignment - 1)
-			& ~(alignment - 1);
+  size_t new_reclen = (dp64->d_reclen - size_diff + alignment - 1)
+		       & ~(alignment - 1);
   if (new_reclen > return_buffer_size)
     /* Overflow.  */
     return NULL;
diff --git a/sysdeps/unix/sysv/linux/rewinddir.c b/sysdeps/unix/sysv/linux/rewinddir.c
index 860bfda004..8db0d0be4a 100644
--- a/sysdeps/unix/sysv/linux/rewinddir.c
+++ b/sysdeps/unix/sysv/linux/rewinddir.c
@@ -33,6 +33,11 @@ __rewinddir (DIR *dirp)
   dirp->offset = 0;
   dirp->size = 0;
   dirp->errcode = 0;
+
+#ifndef __LP64__
+  dirstream_loc_clear (&dirp->locs);
+#endif
+
 #if IS_IN (libc)
   __libc_lock_unlock (dirp->lock);
 #endif
diff --git a/sysdeps/unix/sysv/linux/seekdir.c b/sysdeps/unix/sysv/linux/seekdir.c
index 3c30520928..5f39ef9eef 100644
--- a/sysdeps/unix/sysv/linux/seekdir.c
+++ b/sysdeps/unix/sysv/linux/seekdir.c
@@ -22,14 +22,40 @@
 #include <dirstream.h>
 
 /* Seek to position POS in DIRP.  */
-/* XXX should be __seekdir ? */
 void
 seekdir (DIR *dirp, long int pos)
 {
+  off64_t filepos;
+
   __libc_lock_lock (dirp->lock);
-  (void) __lseek (dirp->fd, pos, SEEK_SET);
-  dirp->size = 0;
-  dirp->offset = 0;
-  dirp->filepos = pos;
+
+#ifndef __LP64__
+  union dirstream_packed dsp;
+
+  dsp.l = pos;
+
+  if (dsp.p.is_packed == 1)
+    filepos = dsp.p.info;
+  else
+    {
+      size_t index = dsp.p.info;
+
+      if (index >= dirstream_loc_size (&dirp->locs))
+	return;
+      struct dirstream_loc *loc = dirstream_loc_at (&dirp->locs, index);
+      filepos = loc->filepos;
+    }
+#else
+  filepos = pos;
+#endif
+
+  if (dirp->filepos != filepos)
+    {
+      __lseek64 (dirp->fd, filepos, SEEK_SET);
+      dirp->filepos = filepos;
+      dirp->offset = 0;
+      dirp->size = 0;
+    }
+
   __libc_lock_unlock (dirp->lock);
 }
diff --git a/sysdeps/unix/sysv/linux/telldir.c b/sysdeps/unix/sysv/linux/telldir.c
index 57d435ed21..bb33626fa4 100644
--- a/sysdeps/unix/sysv/linux/telldir.c
+++ b/sysdeps/unix/sysv/linux/telldir.c
@@ -18,16 +18,59 @@
 #include <dirent.h>
 
 #include <dirstream.h>
+#include <telldir.h>
 
 /* Return the current position of DIRP.  */
 long int
 telldir (DIR *dirp)
 {
-  long int ret;
+#ifndef __LP64__
+  /* If the directory position fits in the packet structure returns it.
+     Otherwise, check if the position is already been recorded in the
+     dynamic array.  If not, add the new record.  */
+
+  union dirstream_packed dsp;
+  size_t i;
 
   __libc_lock_lock (dirp->lock);
-  ret = dirp->filepos;
+
+  if (dirp->filepos < (1U << 31))
+    {
+      dsp.p.is_packed = 1;
+      dsp.p.info = dirp->filepos;
+      goto out;
+    }
+
+  dsp.l = -1;
+
+  for (i = 0; i < dirstream_loc_size (&dirp->locs); i++)
+    {
+      struct dirstream_loc *loc = dirstream_loc_at (&dirp->locs, i);
+      if (loc->filepos == dirp->filepos)
+	break;
+    }
+  if (i == dirstream_loc_size (&dirp->locs))
+    {
+      dirstream_loc_add (&dirp->locs,
+	(struct dirstream_loc) { dirp->filepos });
+      if (dirstream_loc_has_failed (&dirp->locs))
+	goto out;
+    }
+
+  dsp.p.is_packed = 0;
+  /* This assignment might overflow, however most likely ENOMEM would happen
+     long before.  */
+  dsp.p.info = i;
+
+out:
   __libc_lock_unlock (dirp->lock);
 
+  return dsp.l;
+#else
+  long int ret;
+  __libc_lock_lock (dirp->lock);
+  ret = dirp->filepos;
+  __libc_lock_unlock (dirp->lock);
   return ret;
+#endif
 }
diff --git a/sysdeps/unix/sysv/linux/telldir.h b/sysdeps/unix/sysv/linux/telldir.h
new file mode 100644
index 0000000000..7c45886341
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/telldir.h
@@ -0,0 +1,64 @@
+/* Linux internal telldir definitions.
+   Copyright (C) 2020 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#ifndef _TELLDIR_H
+#define _TELLDIR_H 1
+
+#ifndef __LP64__
+
+/* On platforms where long int is smaller than off64_t this is how the
+   returned value is encoded and returned by 'telldir'.  If the directory
+   offset can be enconded in 31 bits it is returned in the 'info' member
+   with 'is_packed' set to 1.
+
+   Otherwise, the 'info' member describes an index in a dynamic array at
+   'DIR' structure.  */
+
+union dirstream_packed
+{
+  long int l;
+  struct
+  {
+    unsigned long is_packed:1;
+    unsigned long info:31;
+  } p;
+};
+
+_Static_assert (sizeof (long int) == sizeof (union dirstream_packed),
+		"sizeof (long int) != sizeof (union dirstream_packed)");
+
+/* telldir will mantain a list of offsets that describe the obtained diretory
+   position if it can fit this information in the returned 'dirstream_packed'
+   struct.  */
+
+struct dirstream_loc
+{
+  off64_t filepos;
+};
+
+# define DYNARRAY_STRUCT  dirstream_loc_t
+# define DYNARRAY_ELEMENT struct dirstream_loc
+# define DYNARRAY_PREFIX  dirstream_loc_
+# include <malloc/dynarray-skeleton.c>
+#else
+
+_Static_assert (sizeof (long int) == sizeof (off64_t),
+		"sizeof (long int) != sizeof (off64_t)");
+#endif /* __LP64__  */
+
+#endif /* _TELLDIR_H  */


^ permalink raw reply	[flat|nested] 5+ messages in thread

* [glibc/azanella/bz23960] linux: Set internal DIR filepos as off64_t [BZ #23960, BZ #24050]
@ 2020-04-15 14:14 Adhemerval Zanella
  0 siblings, 0 replies; 5+ messages in thread
From: Adhemerval Zanella @ 2020-04-15 14:14 UTC (permalink / raw)
  To: glibc-cvs

https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=e3315202b5a1f0570d85696202a5b887362496a6

commit e3315202b5a1f0570d85696202a5b887362496a6
Author: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Date:   Mon Apr 13 18:09:20 2020 -0300

    linux: Set internal DIR filepos as off64_t [BZ #23960, BZ #24050]
    
    It allows to obtain the expected entry offset on telldir and set
    it correctly on seekdir on platforms where long int is smaller
    than off64_t.
    
    On such cases telldir will mantain an internal list that maps the
    DIR object off64_t offsets to the returned long int (the function
    return value).  The seekdir will then set the correct offset from
    the internal list using the telldir as the list key.
    
    It also removes the overflow check on readdir and the returned value
    will be truncated by the non-LFS off_t size.  As Joseph has noted
    in BZ #23960 comment #22, d_off is an opaque value and since
    telldir/seekdir works regardless of the returned dirent d_off value.
    
    Finally it removed the requirement to check for overflow values on
    telldir (BZ #24050).
    
    Checked on i686-linux-gnu and x86_64-linux-gnu.

Diff:
---
 dirent/Makefile                     |   2 +-
 dirent/tst-seekdir2.c               | 156 ++++++++++++++++++++++++++++++++++++
 support/temp_file.c                 |  12 ++-
 support/temp_file.h                 |   7 ++
 sysdeps/unix/sysv/linux/closedir.c  |   4 +
 sysdeps/unix/sysv/linux/dirstream.h |   7 +-
 sysdeps/unix/sysv/linux/opendir.c   |   3 +
 sysdeps/unix/sysv/linux/readdir.c   |   7 +-
 sysdeps/unix/sysv/linux/readdir.h   |   3 -
 sysdeps/unix/sysv/linux/rewinddir.c |   5 ++
 sysdeps/unix/sysv/linux/seekdir.c   |  36 +++++++--
 sysdeps/unix/sysv/linux/telldir.c   |  47 ++++++++++-
 sysdeps/unix/sysv/linux/telldir.h   |  64 +++++++++++++++
 13 files changed, 331 insertions(+), 22 deletions(-)

diff --git a/dirent/Makefile b/dirent/Makefile
index e917d5ceab..f100431845 100644
--- a/dirent/Makefile
+++ b/dirent/Makefile
@@ -31,7 +31,7 @@ routines	:= opendir closedir readdir readdir_r rewinddir \
 		   scandir-cancel scandir-tail scandir64-tail
 
 tests	   := list tst-seekdir opendir-tst1 bug-readdir1 tst-fdopendir \
-	      tst-fdopendir2 tst-scandir tst-scandir64
+	      tst-fdopendir2 tst-scandir tst-scandir64 tst-seekdir2 \
 
 CFLAGS-scandir.c += $(uses-callbacks)
 CFLAGS-scandir64.c += $(uses-callbacks)
diff --git a/dirent/tst-seekdir2.c b/dirent/tst-seekdir2.c
new file mode 100644
index 0000000000..4bd2509f72
--- /dev/null
+++ b/dirent/tst-seekdir2.c
@@ -0,0 +1,156 @@
+/* Check multiple telldir and seekdir.
+   Copyright (C) 2020 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#include <dirent.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <stdio.h>
+#include <string.h>
+
+#include <support/temp_file.h>
+#include <support/support.h>
+#include <support/check.h>
+
+/* Some filesystems returns a arbitrary value for d_off direnty entry (ext4
+   for instance, where the value is an internal hash key).  The idea of
+   create a large number of file is to try trigger a overflow d_off value
+   in a entry to check if telldir/seekdir does work corretly in such
+   case.  */
+static const char *dirname;
+static const size_t nfiles = 10240;
+
+static void
+do_prepare (int argc, char *argv[])
+{
+  dirname = support_create_temp_directory ("tst-seekdir2-");
+
+  for (size_t i = 0; i < nfiles; i++)
+    {
+      int fd = create_temp_file_in_dir ("tempfile.", dirname, NULL);
+      TEST_VERIFY_EXIT (fd > 0);
+      close (fd);
+    }
+}
+#define PREPARE do_prepare
+
+/* Check for old non Large File Support (LFS).  */
+static int
+do_test_not_lfs (void)
+{
+  DIR *dirp;
+  struct dirent *dp;
+  size_t dirp_count;
+
+  dirp = opendir (dirname);
+  TEST_VERIFY_EXIT (dirp != NULL);
+
+  dirp_count = 0;
+  for (dp = readdir (dirp);
+       dp != NULL;
+       dp = readdir (dirp))
+    dirp_count++;
+
+  /* The 2 extra files are '.' and '..'.  */
+  TEST_COMPARE (dirp_count, nfiles + 2);
+
+  rewinddir (dirp);
+
+  long *tdirp = xmalloc (dirp_count * sizeof (long));
+  struct dirent *ddirp = xmalloc (dirp_count * sizeof (struct dirent));
+
+  size_t i = 0;
+  do
+    {
+      tdirp[i] = telldir (dirp);
+      dp = readdir (dirp);
+      TEST_VERIFY_EXIT (dp != NULL);
+      memcpy (&ddirp[i], dp, sizeof (struct dirent));
+    } while (++i < dirp_count);
+
+  for (i = 0; i < dirp_count - 1; i++)
+    {
+      seekdir (dirp, tdirp[i]);
+      dp = readdir (dirp);
+      TEST_COMPARE (strcmp (dp->d_name, ddirp[i].d_name), 0);
+      TEST_COMPARE (dp->d_ino, ddirp[i].d_ino);
+      TEST_COMPARE (dp->d_off, ddirp[i].d_off);
+    }
+
+  closedir (dirp);
+
+  return 0;
+}
+
+/* Same as before but with LFS support.  */
+static int
+do_test_lfs (void)
+{
+  DIR *dirp;
+  struct dirent64 *dp;
+  size_t dirp_count;
+
+  dirp = opendir (dirname);
+  TEST_VERIFY_EXIT (dirp != NULL);
+
+  dirp_count = 0;
+  for (dp = readdir64 (dirp);
+       dp != NULL;
+       dp = readdir64 (dirp))
+    dirp_count++;
+
+  /* The 2 extra files are '.' and '..'.  */
+  TEST_COMPARE (dirp_count, nfiles + 2);
+
+  rewinddir (dirp);
+
+  long *tdirp = xmalloc (dirp_count * sizeof (long));
+  struct dirent64 *ddirp = xmalloc (dirp_count * sizeof (struct dirent64));
+
+  size_t i = 0;
+  do
+    {
+      tdirp[i] = telldir (dirp);
+      dp = readdir64 (dirp);
+      TEST_VERIFY_EXIT (dp != NULL);
+      memcpy (&ddirp[i], dp, sizeof (struct dirent64));
+    } while (++i < dirp_count);
+
+  for (i = 0; i < dirp_count - 1; i++)
+    {
+      seekdir (dirp, tdirp[i]);
+      dp = readdir64 (dirp);
+      TEST_COMPARE (strcmp (dp->d_name, ddirp[i].d_name), 0);
+      TEST_COMPARE (dp->d_ino, ddirp[i].d_ino);
+      TEST_COMPARE (dp->d_off, ddirp[i].d_off);
+    }
+
+  closedir (dirp);
+
+  return 0;
+}
+
+static int
+do_test (void)
+{
+  do_test_not_lfs ();
+  do_test_lfs ();
+
+  return 0;
+}
+
+#include <support/test-driver.c>
diff --git a/support/temp_file.c b/support/temp_file.c
index 277c5e0cf1..98bd235526 100644
--- a/support/temp_file.c
+++ b/support/temp_file.c
@@ -60,14 +60,12 @@ add_temp_file (const char *name)
 }
 
 int
-create_temp_file (const char *base, char **filename)
+create_temp_file_in_dir (const char *base, const char *dir, char **filename)
 {
   char *fname;
   int fd;
 
-  fname = (char *) xmalloc (strlen (test_dir) + 1 + strlen (base)
-			    + sizeof ("XXXXXX"));
-  strcpy (stpcpy (stpcpy (stpcpy (fname, test_dir), "/"), base), "XXXXXX");
+  fname = xasprintf ("%s/%sXXXXXX", dir, base);
 
   fd = mkstemp (fname);
   if (fd == -1)
@@ -86,6 +84,12 @@ create_temp_file (const char *base, char **filename)
   return fd;
 }
 
+int
+create_temp_file (const char *base, char **filename)
+{
+  return create_temp_file_in_dir (base, test_dir, filename);
+}
+
 char *
 support_create_temp_directory (const char *base)
 {
diff --git a/support/temp_file.h b/support/temp_file.h
index 8b6303a6e4..ac61105428 100644
--- a/support/temp_file.h
+++ b/support/temp_file.h
@@ -32,6 +32,13 @@ void add_temp_file (const char *name);
    *FILENAME.  */
 int create_temp_file (const char *base, char **filename);
 
+/* Create a temporary file in directory DIR.  Return the opened file
+   descriptor on success, or -1 on failure.  Write the file name to
+   *FILENAME if FILENAME is not NULL.  In this case, the caller is
+   expected to free *FILENAME.  */
+int create_temp_file_in_dir (const char *base, const char *dir,
+			     char **filename);
+
 /* Create a temporary directory and schedule it for deletion.  BASE is
    used as a prefix for the unique directory name, which the function
    returns.  The caller should free this string.  */
diff --git a/sysdeps/unix/sysv/linux/closedir.c b/sysdeps/unix/sysv/linux/closedir.c
index ccc19eefcd..c39f58aba5 100644
--- a/sysdeps/unix/sysv/linux/closedir.c
+++ b/sysdeps/unix/sysv/linux/closedir.c
@@ -43,6 +43,10 @@ __closedir (DIR *dirp)
 
   fd = dirp->fd;
 
+#ifndef __LP64__
+  dirstream_loc_clear (&dirp->locs);
+#endif
+
 #if IS_IN (libc)
   __libc_lock_fini (dirp->lock);
 #endif
diff --git a/sysdeps/unix/sysv/linux/dirstream.h b/sysdeps/unix/sysv/linux/dirstream.h
index a3ea2b7197..664d73cd40 100644
--- a/sysdeps/unix/sysv/linux/dirstream.h
+++ b/sysdeps/unix/sysv/linux/dirstream.h
@@ -21,6 +21,7 @@
 #include <sys/types.h>
 
 #include <libc-lock.h>
+#include <telldir.h>
 
 /* Directory stream type.
 
@@ -37,10 +38,14 @@ struct __dirstream
     size_t size;		/* Total valid data in the block.  */
     size_t offset;		/* Current offset into the block.  */
 
-    off_t filepos;		/* Position of next entry to read.  */
+    off64_t filepos;		/* Position of next entry to read.  */
 
     int errcode;		/* Delayed error code.  */
 
+#ifndef __LP64__
+    struct dirstream_loc_t locs;
+#endif
+
     /* Directory block.  We must make sure that this block starts
        at an address that is aligned adequately enough to store
        dirent entries.  Using the alignment of "void *" is not
diff --git a/sysdeps/unix/sysv/linux/opendir.c b/sysdeps/unix/sysv/linux/opendir.c
index b60a690150..2bbf2f1271 100644
--- a/sysdeps/unix/sysv/linux/opendir.c
+++ b/sysdeps/unix/sysv/linux/opendir.c
@@ -134,6 +134,9 @@ __alloc_dir (int fd, bool close_fd, int flags, const struct stat64 *statp)
   dirp->offset = 0;
   dirp->filepos = 0;
   dirp->errcode = 0;
+#ifndef __LP64__
+  dirstream_loc_init (&dirp->locs);
+#endif
 
   return dirp;
 }
diff --git a/sysdeps/unix/sysv/linux/readdir.c b/sysdeps/unix/sysv/linux/readdir.c
index 8eab0f4c9b..20b4b4ecff 100644
--- a/sysdeps/unix/sysv/linux/readdir.c
+++ b/sysdeps/unix/sysv/linux/readdir.c
@@ -17,6 +17,7 @@
    <https://www.gnu.org/licenses/>.  */
 
 #include <dirent.h>
+#include <unistd.h>
 
 #if !_DIRENT_MATCHES_DIRENT64
 #include <readdir.h>
@@ -33,7 +34,6 @@ __readdir_unlocked (DIR *dirp)
       if (dirp->offset >= dirp->size)
 	{
 	  /* We've emptied out our buffer.  Refill it.  */
-
 	  ssize_t bytes = __getdents64 (dirp->fd, dirstream_data (dirp),
 					dirstream_alloc_size (dirp));
 	  if (bytes <= 0)
@@ -57,11 +57,6 @@ __readdir_unlocked (DIR *dirp)
 	}
 
       dp = dirstream_ret_entry (dirp);
-      if (dp == NULL)
-	{
-	  __set_errno (EOVERFLOW);
-	  break;
-	}
 
       /* Skip deleted files.  */
     } while (dp->d_ino == 0);
diff --git a/sysdeps/unix/sysv/linux/readdir.h b/sysdeps/unix/sysv/linux/readdir.h
index 4b9d2e8e20..581266f2c5 100644
--- a/sysdeps/unix/sysv/linux/readdir.h
+++ b/sysdeps/unix/sysv/linux/readdir.h
@@ -85,9 +85,6 @@ dirstream_ret_entry (struct __dirstream *ds)
 
   ds->offset += dp->d_reclen;
   ds->filepos = dp64->d_off;
-  if (ds->filepos != dp64->d_off)
-    /* Overflow.  */
-    return NULL;
 
   return dp;
 }
diff --git a/sysdeps/unix/sysv/linux/rewinddir.c b/sysdeps/unix/sysv/linux/rewinddir.c
index 860bfda004..8db0d0be4a 100644
--- a/sysdeps/unix/sysv/linux/rewinddir.c
+++ b/sysdeps/unix/sysv/linux/rewinddir.c
@@ -33,6 +33,11 @@ __rewinddir (DIR *dirp)
   dirp->offset = 0;
   dirp->size = 0;
   dirp->errcode = 0;
+
+#ifndef __LP64__
+  dirstream_loc_clear (&dirp->locs);
+#endif
+
 #if IS_IN (libc)
   __libc_lock_unlock (dirp->lock);
 #endif
diff --git a/sysdeps/unix/sysv/linux/seekdir.c b/sysdeps/unix/sysv/linux/seekdir.c
index 3c30520928..5f39ef9eef 100644
--- a/sysdeps/unix/sysv/linux/seekdir.c
+++ b/sysdeps/unix/sysv/linux/seekdir.c
@@ -22,14 +22,40 @@
 #include <dirstream.h>
 
 /* Seek to position POS in DIRP.  */
-/* XXX should be __seekdir ? */
 void
 seekdir (DIR *dirp, long int pos)
 {
+  off64_t filepos;
+
   __libc_lock_lock (dirp->lock);
-  (void) __lseek (dirp->fd, pos, SEEK_SET);
-  dirp->size = 0;
-  dirp->offset = 0;
-  dirp->filepos = pos;
+
+#ifndef __LP64__
+  union dirstream_packed dsp;
+
+  dsp.l = pos;
+
+  if (dsp.p.is_packed == 1)
+    filepos = dsp.p.info;
+  else
+    {
+      size_t index = dsp.p.info;
+
+      if (index >= dirstream_loc_size (&dirp->locs))
+	return;
+      struct dirstream_loc *loc = dirstream_loc_at (&dirp->locs, index);
+      filepos = loc->filepos;
+    }
+#else
+  filepos = pos;
+#endif
+
+  if (dirp->filepos != filepos)
+    {
+      __lseek64 (dirp->fd, filepos, SEEK_SET);
+      dirp->filepos = filepos;
+      dirp->offset = 0;
+      dirp->size = 0;
+    }
+
   __libc_lock_unlock (dirp->lock);
 }
diff --git a/sysdeps/unix/sysv/linux/telldir.c b/sysdeps/unix/sysv/linux/telldir.c
index 57d435ed21..bb33626fa4 100644
--- a/sysdeps/unix/sysv/linux/telldir.c
+++ b/sysdeps/unix/sysv/linux/telldir.c
@@ -18,16 +18,59 @@
 #include <dirent.h>
 
 #include <dirstream.h>
+#include <telldir.h>
 
 /* Return the current position of DIRP.  */
 long int
 telldir (DIR *dirp)
 {
-  long int ret;
+#ifndef __LP64__
+  /* If the directory position fits in the packet structure returns it.
+     Otherwise, check if the position is already been recorded in the
+     dynamic array.  If not, add the new record.  */
+
+  union dirstream_packed dsp;
+  size_t i;
 
   __libc_lock_lock (dirp->lock);
-  ret = dirp->filepos;
+
+  if (dirp->filepos < (1U << 31))
+    {
+      dsp.p.is_packed = 1;
+      dsp.p.info = dirp->filepos;
+      goto out;
+    }
+
+  dsp.l = -1;
+
+  for (i = 0; i < dirstream_loc_size (&dirp->locs); i++)
+    {
+      struct dirstream_loc *loc = dirstream_loc_at (&dirp->locs, i);
+      if (loc->filepos == dirp->filepos)
+	break;
+    }
+  if (i == dirstream_loc_size (&dirp->locs))
+    {
+      dirstream_loc_add (&dirp->locs,
+	(struct dirstream_loc) { dirp->filepos });
+      if (dirstream_loc_has_failed (&dirp->locs))
+	goto out;
+    }
+
+  dsp.p.is_packed = 0;
+  /* This assignment might overflow, however most likely ENOMEM would happen
+     long before.  */
+  dsp.p.info = i;
+
+out:
   __libc_lock_unlock (dirp->lock);
 
+  return dsp.l;
+#else
+  long int ret;
+  __libc_lock_lock (dirp->lock);
+  ret = dirp->filepos;
+  __libc_lock_unlock (dirp->lock);
   return ret;
+#endif
 }
diff --git a/sysdeps/unix/sysv/linux/telldir.h b/sysdeps/unix/sysv/linux/telldir.h
new file mode 100644
index 0000000000..7c45886341
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/telldir.h
@@ -0,0 +1,64 @@
+/* Linux internal telldir definitions.
+   Copyright (C) 2020 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#ifndef _TELLDIR_H
+#define _TELLDIR_H 1
+
+#ifndef __LP64__
+
+/* On platforms where long int is smaller than off64_t this is how the
+   returned value is encoded and returned by 'telldir'.  If the directory
+   offset can be enconded in 31 bits it is returned in the 'info' member
+   with 'is_packed' set to 1.
+
+   Otherwise, the 'info' member describes an index in a dynamic array at
+   'DIR' structure.  */
+
+union dirstream_packed
+{
+  long int l;
+  struct
+  {
+    unsigned long is_packed:1;
+    unsigned long info:31;
+  } p;
+};
+
+_Static_assert (sizeof (long int) == sizeof (union dirstream_packed),
+		"sizeof (long int) != sizeof (union dirstream_packed)");
+
+/* telldir will mantain a list of offsets that describe the obtained diretory
+   position if it can fit this information in the returned 'dirstream_packed'
+   struct.  */
+
+struct dirstream_loc
+{
+  off64_t filepos;
+};
+
+# define DYNARRAY_STRUCT  dirstream_loc_t
+# define DYNARRAY_ELEMENT struct dirstream_loc
+# define DYNARRAY_PREFIX  dirstream_loc_
+# include <malloc/dynarray-skeleton.c>
+#else
+
+_Static_assert (sizeof (long int) == sizeof (off64_t),
+		"sizeof (long int) != sizeof (off64_t)");
+#endif /* __LP64__  */
+
+#endif /* _TELLDIR_H  */


^ permalink raw reply	[flat|nested] 5+ messages in thread

* [glibc/azanella/bz23960] linux: Set internal DIR filepos as off64_t [BZ #23960, BZ #24050]
@ 2020-04-14 21:09 Adhemerval Zanella
  0 siblings, 0 replies; 5+ messages in thread
From: Adhemerval Zanella @ 2020-04-14 21:09 UTC (permalink / raw)
  To: glibc-cvs

https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=39d7abcfecef2d8e3e3a25e53bd42f706ad990c1

commit 39d7abcfecef2d8e3e3a25e53bd42f706ad990c1
Author: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Date:   Mon Apr 13 18:09:20 2020 -0300

    linux: Set internal DIR filepos as off64_t [BZ #23960, BZ #24050]
    
    It allows to obtain the expected entry offset on telldir and set
    it correctly on seekdir on platforms where long int is smaller
    than off64_t.
    
    On such cases telldir will mantain an internal list of offsets per
    DIR object that maps a long int, the function return value, to a
    off64_t, the directory entry offset.  The seekdir will then obtained
    the correct offset from the internal list and rewinddir resets
    the list as well.
    
    It also removes the overflow check on readdir and the returned value
    will be truncated by the non-LFS off_t size.  As Joseph has noted
    in BZ #23960 comment #22, d_off is an opaque value and telldir/seekdir
    works using the DIR filepos field.
    
    Finally it removed the requirement to check for overflow values on
    telldir (BZ #24050).
    
    Checked on i686-linux-gnu and x86_64-linux-gnu.

Diff:
---
 dirent/Makefile                           |   2 +-
 dirent/tst-seekdir2.c                     | 149 ++++++++++++++++++++++++++++++
 support/temp_file.c                       |  12 ++-
 support/temp_file.h                       |   7 ++
 sysdeps/unix/sysv/linux/closedir.c        |   4 +
 sysdeps/unix/sysv/linux/dirstream.h       |   7 +-
 sysdeps/unix/sysv/linux/dirstream_nolfs.h |   5 +-
 sysdeps/unix/sysv/linux/opendir.c         |   3 +
 sysdeps/unix/sysv/linux/readdir.c         |   7 +-
 sysdeps/unix/sysv/linux/rewinddir.c       |   5 +
 sysdeps/unix/sysv/linux/seekdir.c         |  34 ++++++-
 sysdeps/unix/sysv/linux/telldir.c         |  47 +++++++++-
 sysdeps/unix/sysv/linux/telldir.h         |  64 +++++++++++++
 13 files changed, 323 insertions(+), 23 deletions(-)

diff --git a/dirent/Makefile b/dirent/Makefile
index e917d5ceab..f100431845 100644
--- a/dirent/Makefile
+++ b/dirent/Makefile
@@ -31,7 +31,7 @@ routines	:= opendir closedir readdir readdir_r rewinddir \
 		   scandir-cancel scandir-tail scandir64-tail
 
 tests	   := list tst-seekdir opendir-tst1 bug-readdir1 tst-fdopendir \
-	      tst-fdopendir2 tst-scandir tst-scandir64
+	      tst-fdopendir2 tst-scandir tst-scandir64 tst-seekdir2 \
 
 CFLAGS-scandir.c += $(uses-callbacks)
 CFLAGS-scandir64.c += $(uses-callbacks)
diff --git a/dirent/tst-seekdir2.c b/dirent/tst-seekdir2.c
new file mode 100644
index 0000000000..74fe6d9da5
--- /dev/null
+++ b/dirent/tst-seekdir2.c
@@ -0,0 +1,149 @@
+/* TODO:
+   Copyright (C) 2020 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#include <dirent.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <stdio.h>
+#include <string.h>
+
+#include <support/temp_file.h>
+#include <support/support.h>
+#include <support/check.h>
+
+static const char *dirname;
+static const size_t nfiles = 10240;
+
+static void
+do_prepare (int argc, char *argv[])
+{
+  dirname = support_create_temp_directory ("tst-seekdir2-");
+
+  for (size_t i = 0; i < nfiles; i++)
+    {
+      int fd = create_temp_file_in_dir ("tempfile.", dirname, NULL);
+      TEST_VERIFY_EXIT (fd > 0);
+      close (fd);
+    }
+}
+#define PREPARE do_prepare
+
+static int
+do_test_not_lfs (void)
+{
+  DIR *dirp;
+  struct dirent *dp;
+  size_t dirp_count;
+
+  dirp = opendir (dirname);
+  TEST_VERIFY_EXIT (dirp != NULL);
+
+  dirp_count = 0;
+  for (dp = readdir (dirp);
+       dp != NULL;
+       dp = readdir (dirp))
+    dirp_count++;
+
+  /* The 2 extra files are '.' and '..'.  */
+  TEST_COMPARE (dirp_count, nfiles + 2);
+
+  rewinddir (dirp);
+
+  long *tdirp = xmalloc (dirp_count * sizeof (long));
+  struct dirent *ddirp = xmalloc (dirp_count * sizeof (struct dirent));
+
+  size_t i = 0;
+  do
+    {
+      tdirp[i] = telldir (dirp);
+      dp = readdir (dirp);
+      TEST_VERIFY_EXIT (dp != NULL);
+      memcpy (&ddirp[i], dp, sizeof (struct dirent));
+    } while (++i < dirp_count);
+
+  for (i = 0; i < dirp_count - 1; i++)
+    {
+      seekdir (dirp, tdirp[i]);
+      dp = readdir (dirp);
+      TEST_COMPARE (strcmp (dp->d_name, ddirp[i].d_name), 0);
+      TEST_COMPARE (dp->d_ino, ddirp[i].d_ino);
+      TEST_COMPARE (dp->d_off, ddirp[i].d_off);
+    }
+
+  closedir (dirp);
+
+  return 0;
+}
+
+static int
+do_test_lfs (void)
+{
+  DIR *dirp;
+  struct dirent64 *dp;
+  size_t dirp_count;
+
+  dirp = opendir (dirname);
+  TEST_VERIFY_EXIT (dirp != NULL);
+
+  dirp_count = 0;
+  for (dp = readdir64 (dirp);
+       dp != NULL;
+       dp = readdir64 (dirp))
+    dirp_count++;
+
+  /* The 2 extra files are '.' and '..'.  */
+  TEST_COMPARE (dirp_count, nfiles + 2);
+
+  rewinddir (dirp);
+
+  long *tdirp = xmalloc (dirp_count * sizeof (long));
+  struct dirent64 *ddirp = xmalloc (dirp_count * sizeof (struct dirent64));
+
+  size_t i = 0;
+  do
+    {
+      tdirp[i] = telldir (dirp);
+      dp = readdir64 (dirp);
+      TEST_VERIFY_EXIT (dp != NULL);
+      memcpy (&ddirp[i], dp, sizeof (struct dirent64));
+    } while (++i < dirp_count);
+
+  for (i = 0; i < dirp_count - 1; i++)
+    {
+      seekdir (dirp, tdirp[i]);
+      dp = readdir64 (dirp);
+      TEST_COMPARE (strcmp (dp->d_name, ddirp[i].d_name), 0);
+      TEST_COMPARE (dp->d_ino, ddirp[i].d_ino);
+      TEST_COMPARE (dp->d_off, ddirp[i].d_off);
+    }
+
+  closedir (dirp);
+
+  return 0;
+}
+
+static int
+do_test (void)
+{
+  do_test_not_lfs ();
+  do_test_lfs ();
+
+  return 0;
+}
+
+#include <support/test-driver.c>
diff --git a/support/temp_file.c b/support/temp_file.c
index 277c5e0cf1..98bd235526 100644
--- a/support/temp_file.c
+++ b/support/temp_file.c
@@ -60,14 +60,12 @@ add_temp_file (const char *name)
 }
 
 int
-create_temp_file (const char *base, char **filename)
+create_temp_file_in_dir (const char *base, const char *dir, char **filename)
 {
   char *fname;
   int fd;
 
-  fname = (char *) xmalloc (strlen (test_dir) + 1 + strlen (base)
-			    + sizeof ("XXXXXX"));
-  strcpy (stpcpy (stpcpy (stpcpy (fname, test_dir), "/"), base), "XXXXXX");
+  fname = xasprintf ("%s/%sXXXXXX", dir, base);
 
   fd = mkstemp (fname);
   if (fd == -1)
@@ -86,6 +84,12 @@ create_temp_file (const char *base, char **filename)
   return fd;
 }
 
+int
+create_temp_file (const char *base, char **filename)
+{
+  return create_temp_file_in_dir (base, test_dir, filename);
+}
+
 char *
 support_create_temp_directory (const char *base)
 {
diff --git a/support/temp_file.h b/support/temp_file.h
index 8b6303a6e4..ac61105428 100644
--- a/support/temp_file.h
+++ b/support/temp_file.h
@@ -32,6 +32,13 @@ void add_temp_file (const char *name);
    *FILENAME.  */
 int create_temp_file (const char *base, char **filename);
 
+/* Create a temporary file in directory DIR.  Return the opened file
+   descriptor on success, or -1 on failure.  Write the file name to
+   *FILENAME if FILENAME is not NULL.  In this case, the caller is
+   expected to free *FILENAME.  */
+int create_temp_file_in_dir (const char *base, const char *dir,
+			     char **filename);
+
 /* Create a temporary directory and schedule it for deletion.  BASE is
    used as a prefix for the unique directory name, which the function
    returns.  The caller should free this string.  */
diff --git a/sysdeps/unix/sysv/linux/closedir.c b/sysdeps/unix/sysv/linux/closedir.c
index ccc19eefcd..c39f58aba5 100644
--- a/sysdeps/unix/sysv/linux/closedir.c
+++ b/sysdeps/unix/sysv/linux/closedir.c
@@ -43,6 +43,10 @@ __closedir (DIR *dirp)
 
   fd = dirp->fd;
 
+#ifndef __LP64__
+  dirstream_loc_clear (&dirp->locs);
+#endif
+
 #if IS_IN (libc)
   __libc_lock_fini (dirp->lock);
 #endif
diff --git a/sysdeps/unix/sysv/linux/dirstream.h b/sysdeps/unix/sysv/linux/dirstream.h
index a3ea2b7197..664d73cd40 100644
--- a/sysdeps/unix/sysv/linux/dirstream.h
+++ b/sysdeps/unix/sysv/linux/dirstream.h
@@ -21,6 +21,7 @@
 #include <sys/types.h>
 
 #include <libc-lock.h>
+#include <telldir.h>
 
 /* Directory stream type.
 
@@ -37,10 +38,14 @@ struct __dirstream
     size_t size;		/* Total valid data in the block.  */
     size_t offset;		/* Current offset into the block.  */
 
-    off_t filepos;		/* Position of next entry to read.  */
+    off64_t filepos;		/* Position of next entry to read.  */
 
     int errcode;		/* Delayed error code.  */
 
+#ifndef __LP64__
+    struct dirstream_loc_t locs;
+#endif
+
     /* Directory block.  We must make sure that this block starts
        at an address that is aligned adequately enough to store
        dirent entries.  Using the alignment of "void *" is not
diff --git a/sysdeps/unix/sysv/linux/dirstream_nolfs.h b/sysdeps/unix/sysv/linux/dirstream_nolfs.h
index 21ca5f59be..32f8bf3070 100644
--- a/sysdeps/unix/sysv/linux/dirstream_nolfs.h
+++ b/sysdeps/unix/sysv/linux/dirstream_nolfs.h
@@ -80,10 +80,7 @@ dirstream_ret_entry (struct __dirstream *ds)
 	  dp64->d_reclen - offsetof (struct dirent64, d_name));
 
   ds->offset += dp->d_reclen;
-  ds->filepos = dp->d_off;
-  if (ds->filepos != dp->d_off)
-    /* Overflow.  */
-    return NULL;
+  ds->filepos = dp64->d_off;
 
   return dp;
 }
diff --git a/sysdeps/unix/sysv/linux/opendir.c b/sysdeps/unix/sysv/linux/opendir.c
index 6b8951bbfe..b3b5409452 100644
--- a/sysdeps/unix/sysv/linux/opendir.c
+++ b/sysdeps/unix/sysv/linux/opendir.c
@@ -135,6 +135,9 @@ __alloc_dir (int fd, bool close_fd, int flags, const struct stat64 *statp)
   dirp->offset = 0;
   dirp->filepos = 0;
   dirp->errcode = 0;
+#ifndef __LP64__
+  dirstream_loc_init (&dirp->locs);
+#endif
 
   return dirp;
 }
diff --git a/sysdeps/unix/sysv/linux/readdir.c b/sysdeps/unix/sysv/linux/readdir.c
index a3236d10e6..a5a2b75b31 100644
--- a/sysdeps/unix/sysv/linux/readdir.c
+++ b/sysdeps/unix/sysv/linux/readdir.c
@@ -17,6 +17,7 @@
    <https://www.gnu.org/licenses/>.  */
 
 #include <dirent.h>
+#include <unistd.h>
 
 #if !_DIRENT_MATCHES_DIRENT64
 #include <dirstream_nolfs.h>
@@ -33,7 +34,6 @@ __readdir_unlocked (DIR *dirp)
       if (dirp->offset >= dirp->size)
 	{
 	  /* We've emptied out our buffer.  Refill it.  */
-
 	  ssize_t bytes = __getdents64 (dirp->fd, dirstream_data (dirp),
 					dirstream_alloc_size (dirp));
 	  if (bytes <= 0)
@@ -57,11 +57,6 @@ __readdir_unlocked (DIR *dirp)
 	}
 
       dp = dirstream_ret_entry (dirp);
-      if (dp == NULL)
-	{
-	  __set_errno (EOVERFLOW);
-	  break;
-	}
 
       /* Skip deleted files.  */
     } while (dp->d_ino == 0);
diff --git a/sysdeps/unix/sysv/linux/rewinddir.c b/sysdeps/unix/sysv/linux/rewinddir.c
index 860bfda004..8db0d0be4a 100644
--- a/sysdeps/unix/sysv/linux/rewinddir.c
+++ b/sysdeps/unix/sysv/linux/rewinddir.c
@@ -33,6 +33,11 @@ __rewinddir (DIR *dirp)
   dirp->offset = 0;
   dirp->size = 0;
   dirp->errcode = 0;
+
+#ifndef __LP64__
+  dirstream_loc_clear (&dirp->locs);
+#endif
+
 #if IS_IN (libc)
   __libc_lock_unlock (dirp->lock);
 #endif
diff --git a/sysdeps/unix/sysv/linux/seekdir.c b/sysdeps/unix/sysv/linux/seekdir.c
index 3c30520928..1a215a72f3 100644
--- a/sysdeps/unix/sysv/linux/seekdir.c
+++ b/sysdeps/unix/sysv/linux/seekdir.c
@@ -22,14 +22,38 @@
 #include <dirstream.h>
 
 /* Seek to position POS in DIRP.  */
-/* XXX should be __seekdir ? */
 void
 seekdir (DIR *dirp, long int pos)
 {
+  off64_t filepos;
+
+#ifndef __LP64__
+  union dirstream_packed dsp;
+
+  dsp.l = pos;
+
+  if (dsp.p.is_packed == 1)
+    filepos = dsp.p.info;
+  else
+    {
+      size_t index = dsp.p.info;
+
+      if (index >= dirstream_loc_size (&dirp->locs))
+	return;
+      struct dirstream_loc *loc = dirstream_loc_at (&dirp->locs, index);
+      filepos = loc->filepos;
+    }
+#else
+  filepos = pos;
+#endif
+
   __libc_lock_lock (dirp->lock);
-  (void) __lseek (dirp->fd, pos, SEEK_SET);
-  dirp->size = 0;
-  dirp->offset = 0;
-  dirp->filepos = pos;
+  if (dirp->filepos != filepos)
+    {
+      __lseek64 (dirp->fd, filepos, SEEK_SET);
+      dirp->filepos = filepos;
+      dirp->offset = 0;
+      dirp->size = 0;
+    }
   __libc_lock_unlock (dirp->lock);
 }
diff --git a/sysdeps/unix/sysv/linux/telldir.c b/sysdeps/unix/sysv/linux/telldir.c
index 57d435ed21..bb33626fa4 100644
--- a/sysdeps/unix/sysv/linux/telldir.c
+++ b/sysdeps/unix/sysv/linux/telldir.c
@@ -18,16 +18,59 @@
 #include <dirent.h>
 
 #include <dirstream.h>
+#include <telldir.h>
 
 /* Return the current position of DIRP.  */
 long int
 telldir (DIR *dirp)
 {
-  long int ret;
+#ifndef __LP64__
+  /* If the directory position fits in the packet structure returns it.
+     Otherwise, check if the position is already been recorded in the
+     dynamic array.  If not, add the new record.  */
+
+  union dirstream_packed dsp;
+  size_t i;
 
   __libc_lock_lock (dirp->lock);
-  ret = dirp->filepos;
+
+  if (dirp->filepos < (1U << 31))
+    {
+      dsp.p.is_packed = 1;
+      dsp.p.info = dirp->filepos;
+      goto out;
+    }
+
+  dsp.l = -1;
+
+  for (i = 0; i < dirstream_loc_size (&dirp->locs); i++)
+    {
+      struct dirstream_loc *loc = dirstream_loc_at (&dirp->locs, i);
+      if (loc->filepos == dirp->filepos)
+	break;
+    }
+  if (i == dirstream_loc_size (&dirp->locs))
+    {
+      dirstream_loc_add (&dirp->locs,
+	(struct dirstream_loc) { dirp->filepos });
+      if (dirstream_loc_has_failed (&dirp->locs))
+	goto out;
+    }
+
+  dsp.p.is_packed = 0;
+  /* This assignment might overflow, however most likely ENOMEM would happen
+     long before.  */
+  dsp.p.info = i;
+
+out:
   __libc_lock_unlock (dirp->lock);
 
+  return dsp.l;
+#else
+  long int ret;
+  __libc_lock_lock (dirp->lock);
+  ret = dirp->filepos;
+  __libc_lock_unlock (dirp->lock);
   return ret;
+#endif
 }
diff --git a/sysdeps/unix/sysv/linux/telldir.h b/sysdeps/unix/sysv/linux/telldir.h
new file mode 100644
index 0000000000..7c45886341
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/telldir.h
@@ -0,0 +1,64 @@
+/* Linux internal telldir definitions.
+   Copyright (C) 2020 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#ifndef _TELLDIR_H
+#define _TELLDIR_H 1
+
+#ifndef __LP64__
+
+/* On platforms where long int is smaller than off64_t this is how the
+   returned value is encoded and returned by 'telldir'.  If the directory
+   offset can be enconded in 31 bits it is returned in the 'info' member
+   with 'is_packed' set to 1.
+
+   Otherwise, the 'info' member describes an index in a dynamic array at
+   'DIR' structure.  */
+
+union dirstream_packed
+{
+  long int l;
+  struct
+  {
+    unsigned long is_packed:1;
+    unsigned long info:31;
+  } p;
+};
+
+_Static_assert (sizeof (long int) == sizeof (union dirstream_packed),
+		"sizeof (long int) != sizeof (union dirstream_packed)");
+
+/* telldir will mantain a list of offsets that describe the obtained diretory
+   position if it can fit this information in the returned 'dirstream_packed'
+   struct.  */
+
+struct dirstream_loc
+{
+  off64_t filepos;
+};
+
+# define DYNARRAY_STRUCT  dirstream_loc_t
+# define DYNARRAY_ELEMENT struct dirstream_loc
+# define DYNARRAY_PREFIX  dirstream_loc_
+# include <malloc/dynarray-skeleton.c>
+#else
+
+_Static_assert (sizeof (long int) == sizeof (off64_t),
+		"sizeof (long int) != sizeof (off64_t)");
+#endif /* __LP64__  */
+
+#endif /* _TELLDIR_H  */


^ permalink raw reply	[flat|nested] 5+ messages in thread

end of thread, other threads:[~2020-10-02 13:53 UTC | newest]

Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed)
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2020-10-02 13:53 [glibc/azanella/bz23960] linux: Set internal DIR filepos as off64_t [BZ #23960, BZ #24050] Adhemerval Zanella
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2020-04-17 13:23 Adhemerval Zanella
2020-04-16 13:21 Adhemerval Zanella
2020-04-15 14:14 Adhemerval Zanella
2020-04-14 21:09 Adhemerval Zanella

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