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* [glibc/vineet/arc-port-latest] string: Implement strerror in terms of strerror_l
@ 2020-07-09 16:34 Vineet Gupta
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From: Vineet Gupta @ 2020-07-09 16:34 UTC (permalink / raw)
To: glibc-cvs
https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=28aff047818eb1726394296d27b9c7885340bead
commit 28aff047818eb1726394296d27b9c7885340bead
Author: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Date: Thu May 14 17:44:15 2020 -0300
string: Implement strerror in terms of strerror_l
If the thread is terminated then __libc_thread_freeres will free the
storage via __glibc_tls_internal_free.
It is only within the calling thread that this matters. It makes
strerror MT-safe.
Checked on x86-64-linux-gnu, i686-linux-gnu, powerpc64le-linux-gnu,
and s390x-linux-gnu.
Tested-by: Carlos O'Donell <carlos@redhat.com>
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
Diff:
---
NEWS | 5 +++++
include/string.h | 4 ++++
string/strerror.c | 22 ++--------------------
string/strerror_l.c | 15 ++++++++++-----
sysdeps/mach/strerror_l.c | 4 +++-
5 files changed, 24 insertions(+), 26 deletions(-)
diff --git a/NEWS b/NEWS
index 482d2253e0..5d399293ba 100644
--- a/NEWS
+++ b/NEWS
@@ -79,6 +79,11 @@ Deprecated and removed features, and other changes affecting compatibility:
compatibility symbols to support old binaries. All programs should use
strerror or strerror_r instead.
+* Both strerror and strerror_l now share the same internal buffer in the
+ calling thread, meaning that the returned string pointer may be invalided
+ or contents might be overwritten on subsequent calls in the same thread or
+ if the thread is terminated. It makes strerror MT-safe.
+
Changes to build and runtime requirements:
* powerpc64le requires GCC 7.4 or newer. This is required for supporting
diff --git a/include/string.h b/include/string.h
index 4d622f1c03..3a33327cc0 100644
--- a/include/string.h
+++ b/include/string.h
@@ -4,6 +4,7 @@
/* Some of these are defined as macros in the real string.h, so we must
prototype them before including it. */
#include <sys/types.h>
+#include <locale.h>
extern void *__memccpy (void *__dest, const void *__src,
int __c, size_t __n);
@@ -50,6 +51,8 @@ extern int __ffs (int __i) __attribute__ ((const));
extern char *__strerror_r (int __errnum, char *__buf, size_t __buflen);
+extern char *__strerror_l (int __errnum, locale_t __loc);
+
/* Called as part of the thread shutdown sequence. */
void __strerror_thread_freeres (void) attribute_hidden;
@@ -113,6 +116,7 @@ libc_hidden_proto (memmem)
extern __typeof (memmem) __memmem;
libc_hidden_proto (__memmem)
libc_hidden_proto (__ffs)
+libc_hidden_proto (__strerror_l)
#if IS_IN (libc)
/* Avoid hidden reference to IFUNC symbol __explicit_bzero_chk. */
diff --git a/string/strerror.c b/string/strerror.c
index 283ab70f91..35c749016e 100644
--- a/string/strerror.c
+++ b/string/strerror.c
@@ -15,29 +15,11 @@
License along with the GNU C Library; if not, see
<https://www.gnu.org/licenses/>. */
-#include <libintl.h>
-#include <stdio.h>
#include <string.h>
-#include <errno.h>
-
-/* Return a string describing the errno code in ERRNUM.
- The storage is good only until the next call to strerror.
- Writing to the storage causes undefined behavior. */
-libc_freeres_ptr (static char *buf);
+#include <locale/localeinfo.h>
char *
strerror (int errnum)
{
- char *ret = __strerror_r (errnum, NULL, 0);
- int saved_errno;
-
- if (__glibc_likely (ret != NULL))
- return ret;
- saved_errno = errno;
- if (buf == NULL)
- buf = malloc (1024);
- __set_errno (saved_errno);
- if (buf == NULL)
- return _("Unknown error");
- return __strerror_r (errnum, buf, 1024);
+ return __strerror_l (errnum, __libc_tsd_get (locale_t, LOCALE));
}
diff --git a/string/strerror_l.c b/string/strerror_l.c
index 309f42e66b..017bd14b99 100644
--- a/string/strerror_l.c
+++ b/string/strerror_l.c
@@ -20,8 +20,7 @@
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
-#include <sys/param.h>
-#include <libc-symbols.h>
+#include <errno.h>
static __thread char *last_value;
@@ -38,8 +37,9 @@ translate (const char *str, locale_t loc)
/* Return a string describing the errno code in ERRNUM. */
char *
-strerror_l (int errnum, locale_t loc)
+__strerror_l (int errnum, locale_t loc)
{
+ int saved_errno = errno;
char *err = (char *) __get_errlist (errnum);
if (__glibc_unlikely (err == NULL))
{
@@ -48,11 +48,16 @@ strerror_l (int errnum, locale_t loc)
translate ("Unknown error ", loc), errnum) == -1)
last_value = NULL;
- return last_value;
+ err = last_value;
}
+ else
+ err = (char *) translate (err, loc);
- return (char *) translate (err, loc);
+ __set_errno (saved_errno);
+ return err;
}
+weak_alias (__strerror_l, strerror_l)
+libc_hidden_def (__strerror_l)
void
__strerror_thread_freeres (void)
diff --git a/sysdeps/mach/strerror_l.c b/sysdeps/mach/strerror_l.c
index f514af341e..b6c9fdbe80 100644
--- a/sysdeps/mach/strerror_l.c
+++ b/sysdeps/mach/strerror_l.c
@@ -42,7 +42,7 @@ translate (const char *str, locale_t loc)
/* Return a string describing the errno code in ERRNUM. */
char *
-strerror_l (int errnum, locale_t loc)
+__strerror_l (int errnum, locale_t loc)
{
int system;
int sub;
@@ -86,6 +86,8 @@ strerror_l (int errnum, locale_t loc)
return (char *) translate (es->subsystem[sub].codes[code], loc);
}
+weak_alias (__strerror_l, strerror_l)
+libc_hidden_def (__strerror_l)
/* This is called when a thread is exiting to free the last_value string. */
void
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