Re: [PATCH v3] ftw initial port

[Jeff Johnston <jjohnstn@redhat.com>]

Hi Eshan,

I did review this.  I had questions about your weak_alias macro.  You check
for _weak_alias, then define weak_alias.  If _weak_alias is defined,
why not just use it?  As well, if _weak_alias is not defined, then you are
referencing weak_alias in your code without it being defined.

-- Jeff J.

On Wed, Nov 4, 2020 at 1:21 PM Eshan Dhawan via Newlib <
newlib@sourceware.org> wrote:

> Hello everyone,
> I sent this patch earlier but it seems to be missed between other patches.
> I wanted it if you all could review it.
>
> -Eshan
>
> On Fri, Oct 16, 2020 at 1:16 PM Eshan dhawan <eshandhawan51@gmail.com>
> wrote:
>
> > Signed-off-by: Eshan dhawan <eshandhawan51@gmail.com>
> > ---
> >  newlib/libc/include/ftw.h     |  69 +++++++++++++++
> >  newlib/libc/posix/Makefile.am |   2 +-
> >  newlib/libc/posix/ftw.c       |  34 ++++++++
> >  newlib/libc/posix/nftw.c      | 156 ++++++++++++++++++++++++++++++++++
> >  4 files changed, 260 insertions(+), 1 deletion(-)
> >  create mode 100644 newlib/libc/include/ftw.h
> >  create mode 100644 newlib/libc/posix/ftw.c
> >  create mode 100644 newlib/libc/posix/nftw.c
> >
> > diff --git a/newlib/libc/include/ftw.h b/newlib/libc/include/ftw.h
> > new file mode 100644
> > index 000000000..400701cf5
> > --- /dev/null
> > +++ b/newlib/libc/include/ftw.h
> > @@ -0,0 +1,69 @@
> > +/*
> > +* Copyright © 2005-2020 Rich Felker, et al.
> > +*
> > +* Permission is hereby granted, free of charge, to any person obtaining
> > +* a copy of this software and associated documentation files (the
> > +* "Software"), to deal in the Software without restriction, including
> > +* without limitation the rights to use, copy, modify, merge, publish,
> > +* distribute, sublicense, and/or sell copies of the Software, and to
> > +* permit persons to whom the Software is furnished to do so, subject to
> > +* the following conditions:
> > +*
> > +* The above copyright notice and this permission notice shall be
> > +* included in all copies or substantial portions of the Software.
> > +*
> > +* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
> > +* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
> > +* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
> > +* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
> > +* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
> > +* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
> > +* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
> > +*/
> > +
> > +#ifndef _FTW_H
> > +#define        _FTW_H
> > +
> > +#ifdef __cplusplus
> > +extern "C" {
> > +#endif
> > +
> > +#ifdef _weak_alias(name, aliasname)
> > +#  define weak_alias(name, aliasname) \
> > +  extern __typeof (name) aliasname __attribute__ ((__weak__, __alias__
> > (#name)));
> > +#endif
> > +
> > +#include <sys/features.h>
> > +#include <sys/stat.h>
> > +
> > +#define FTW_F   1
> > +#define FTW_D   2
> > +#define FTW_DNR 3
> > +#define FTW_NS  4
> > +#define FTW_SL  5
> > +#define FTW_DP  6
> > +#define FTW_SLN 7
> > +
> > +#define FTW_PHYS  1
> > +#define FTW_MOUNT 2
> > +#define FTW_CHDIR 4
> > +#define FTW_DEPTH 8
> > +
> > +struct FTW {
> > +       int base;
> > +       int level;
> > +};
> > +
> > +int ftw(const char *, int (*)(const char *, const struct stat *, int),
> > int);
> > +int nftw(const char *, int (*)(const char *, const struct stat *, int,
> > struct FTW *), int, int);
> > +
> > +#if defined(_LARGEFILE64_SOURCE) || defined(_GNU_SOURCE)
> > +#define ftw64 ftw
> > +#define nftw64 nftw
> > +#endif
> > +
> > +#ifdef __cplusplus
> > +}
> > +#endif
> > +
> > +#endif
> > diff --git a/newlib/libc/posix/Makefile.am
> b/newlib/libc/posix/Makefile.am
> > index 6cdee1df0..5a358f782 100644
> > --- a/newlib/libc/posix/Makefile.am
> > +++ b/newlib/libc/posix/Makefile.am
> > @@ -10,7 +10,7 @@ GENERAL_SOURCES = \
> >         opendir.c readdir.c readdir_r.c \
> >         regcomp.c regerror.c regexec.c regfree.c \
> >         rewinddir.c sleep.c usleep.c \
> > -       telldir.c
> > +       telldir.c ftw.c nftw.c
> >
> >  ELIX_2_SOURCES = \
> >          scandir.c seekdir.c
> > diff --git a/newlib/libc/posix/ftw.c b/newlib/libc/posix/ftw.c
> > new file mode 100644
> > index 000000000..fa320e9b0
> > --- /dev/null
> > +++ b/newlib/libc/posix/ftw.c
> > @@ -0,0 +1,34 @@
> > +/*
> > +* Copyright © 2005-2020 Rich Felker, et al.
> > +*
> > +* Permission is hereby granted, free of charge, to any person obtaining
> > +* a copy of this software and associated documentation files (the
> > +* "Software"), to deal in the Software without restriction, including
> > +* without limitation the rights to use, copy, modify, merge, publish,
> > +* distribute, sublicense, and/or sell copies of the Software, and to
> > +* permit persons to whom the Software is furnished to do so, subject to
> > +* the following conditions:
> > +*
> > +* The above copyright notice and this permission notice shall be
> > +* included in all copies or substantial portions of the Software.
> > +*
> > +* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
> > +* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
> > +* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
> > +* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
> > +* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
> > +* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
> > +* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
> > +*/
> > +
> > +#include <ftw.h>
> > +
> > +int ftw(const char *path, int (*fn)(const char *, const struct stat *,
> > int), int fd_limit)
> > +{
> > +       /* The following cast assumes that calling a function with one
> > +        * argument more than it needs behaves as expected. This is
> > +        * actually undefined, but works on all real-world machines. */
> > +       return nftw(path, (int (*)())fn, fd_limit, FTW_PHYS);
> > +}
> > +
> > +weak_alias(ftw, ftw64);
> > diff --git a/newlib/libc/posix/nftw.c b/newlib/libc/posix/nftw.c
> > new file mode 100644
> > index 000000000..0ffca9f67
> > --- /dev/null
> > +++ b/newlib/libc/posix/nftw.c
> > @@ -0,0 +1,156 @@
> > +/*
> > +* Copyright © 2005-2020 Rich Felker, et al.
> > +*
> > +* Permission is hereby granted, free of charge, to any person obtaining
> > +* a copy of this software and associated documentation files (the
> > +* "Software"), to deal in the Software without restriction, including
> > +* without limitation the rights to use, copy, modify, merge, publish,
> > +* distribute, sublicense, and/or sell copies of the Software, and to
> > +* permit persons to whom the Software is furnished to do so, subject to
> > +* the following conditions:
> > +*
> > +* The above copyright notice and this permission notice shall be
> > +* included in all copies or substantial portions of the Software.
> > +*
> > +* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
> > +* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
> > +* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
> > +* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
> > +* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
> > +* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
> > +* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
> > +*/
> > +
> > +#include <ftw.h>
> > +#include <dirent.h>
> > +#include <sys/stat.h>
> > +#include <errno.h>
> > +#include <unistd.h>
> > +#include <string.h>
> > +#include <limits.h>
> > +#include <pthread.h>
> > +
> > +struct history
> > +{
> > +       struct history *chain;
> > +       dev_t dev;
> > +       ino_t ino;
> > +       int level;
> > +       int base;
> > +};
> > +
> > +#undef dirfd
> > +#define dirfd(d) (*(int *)d)
> > +
> > +static int do_nftw(char *path, int (*fn)(const char *, const struct stat
> > *, int, struct FTW *), int fd_limit, int flags, struct history *h)
> > +{
> > +       size_t l = strlen(path), j = l && path[l-1]=='/' ? l-1 : l;
> > +       struct stat st;
> > +       struct history new;
> > +       int type;
> > +       int r;
> > +       struct FTW lev;
> > +
> > +       if ((flags & FTW_PHYS) ? lstat(path, &st) : stat(path, &st) < 0)
> {
> > +               if (!(flags & FTW_PHYS) && errno==ENOENT && !lstat(path,
> > &st))
> > +                       type = FTW_SLN;
> > +               else if (errno != EACCES) return -1;
> > +               else type = FTW_NS;
> > +       } else if (S_ISDIR(st.st_mode)) {
> > +               if (access(path, R_OK) < 0) type = FTW_DNR;
> > +               else if (flags & FTW_DEPTH) type = FTW_DP;
> > +               else type = FTW_D;
> > +       } else if (S_ISLNK(st.st_mode)) {
> > +               if (flags & FTW_PHYS) type = FTW_SL;
> > +               else type = FTW_SLN;
> > +       } else {
> > +               type = FTW_F;
> > +       }
> > +
> > +       if ((flags & FTW_MOUNT) && h && st.st_dev != h->dev)
> > +               return 0;
> > +
> > +       new.chain = h;
> > +       new.dev = st.st_dev;
> > +       new.ino = st.st_ino;
> > +       new.level = h ? h->level+1 : 0;
> > +       new.base = j+1;
> > +
> > +       lev.level = new.level;
> > +       if (h) {
> > +               lev.base = h->base;
> > +       } else {
> > +               size_t k;
> > +               for (k=j; k && path[k]=='/'; k--);
> > +               for (; k && path[k-1]!='/'; k--);
> > +               lev.base = k;
> > +       }
> > +
> > +       if (!(flags & FTW_DEPTH) && (r=fn(path, &st, type, &lev)))
> > +               return r;
> > +
> > +       for (; h; h = h->chain)
> > +               if (h->dev == st.st_dev && h->ino == st.st_ino)
> > +                       return 0;
> > +
> > +       if ((type == FTW_D || type == FTW_DP) && fd_limit) {
> > +               DIR *d = opendir(path);
> > +               if (d) {
> > +                       struct dirent *de;
> > +                       while ((de = readdir(d))) {
> > +                               if (de->d_name[0] == '.'
> > +                                && (!de->d_name[1]
> > +                                 || (de->d_name[1]=='.'
> > +                                  && !de->d_name[2]))) continue;
> > +                               if (strlen(de->d_name) >= PATH_MAX-l) {
> > +                                       errno = ENAMETOOLONG;
> > +                                       closedir(d);
> > +                                       return -1;
> > +                               }
> > +                               path[j]='/';
> > +                               strcpy(path+j+1, de->d_name);
> > +                               if ((r=do_nftw(path, fn, fd_limit-1,
> > flags, &new))) {
> > +                                       closedir(d);
> > +                                       return r;
> > +                               }
> > +                       }
> > +                       closedir(d);
> > +               } else if (errno != EACCES) {
> > +                       return -1;
> > +               }
> > +       }
> > +
> > +       path[l] = 0;
> > +       if ((flags & FTW_DEPTH) && (r=fn(path, &st, type, &lev)))
> > +               return r;
> > +
> > +       return 0;
> > +}
> > +
> > +int nftw(const char *path, int (*fn)(const char *, const struct stat *,
> > int, struct FTW *), int fd_limit, int flags)
> > +{
> > +       int r, cs;
> > +       size_t l;
> > +       char pathbuf[PATH_MAX+1];
> > +
> > +       if (fd_limit <= 0) return 0;
> > +
> > +       l = strlen(path);
> > +       if (l > PATH_MAX) {
> > +               errno = ENAMETOOLONG;
> > +               return -1;
> > +       }
> > +       memcpy(pathbuf, path, l+1);
> > +
> > +#ifdef _STDIO_WITH_THREAD_CANCELLATION_SUPPORT
> > +       pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &cs);
> > +#endif
> > +       r = do_nftw(pathbuf, fn, fd_limit, flags, NULL);
> > +#ifdef _STDIO_WITH_THREAD_CANCELLATION_SUPPORT
> > +       pthread_setcancelstate(cs, 0);
> > +#endif
> > +       return r;
> > +}
> > +
> > +weak_alias(nftw, nftw64);
> > +
> > --
> > 2.17.1
> >
> >
>
>