strerror_r: provide POSIX implementation

* libc/include/string.h (strerror_r): Update declaration.
* libc/string/strerror.c (strerror): Update documentation.
* libc/string/strerror_r.c (strerror_r): Always return
NUL-terminated string; don't overwrite too-short buf.
* libc/string/xpg_strerror_r.c (__xpg_strerror_r): Implement POSIX
variant.
* libc/string/Makefile.am (GENERAL_SOURCES): Build new file.
* libc/string/Makefile.in: Regenerate.
This commit is contained in:
Eric Blake 2011-02-10 16:48:18 +00:00
parent 27aaf2a9d1
commit 7c10a76dec
7 changed files with 115 additions and 13 deletions

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@ -1,3 +1,14 @@
2011-02-09 Eric Blake <eblake@redhat.com>
* libc/include/string.h (strerror_r): Update declaration.
* libc/string/strerror.c (strerror): Update documentation.
* libc/string/strerror_r.c (strerror_r): Always return
NUL-terminated string; don't overwrite too-short buf.
* libc/string/xpg_strerror_r.c (__xpg_strerror_r): Implement POSIX
variant.
* libc/string/Makefile.am (GENERAL_SOURCES): Build new file.
* libc/string/Makefile.in: Regenerate.
2011-01-28 Corinna Vinschen <vinschen@redhat.com>
* libc/stdio/fclose.c: Only use sfp lock to guard non-atomic

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@ -66,7 +66,20 @@ char *_EXFUN(strdup,(const char *));
char *_EXFUN(_strdup_r,(struct _reent *, const char *));
char *_EXFUN(strndup,(const char *, size_t));
char *_EXFUN(_strndup_r,(struct _reent *, const char *, size_t));
/* There are two common strerror_r variants. If you request
_GNU_SOURCE, you get the GNU version; otherwise you get the POSIX
version. POSIX requires that #undef strerror_r will still let you
invoke the underlying function, but that requires gcc support. */
#ifdef _GNU_SOURCE
char *_EXFUN(strerror_r,(int, char *, size_t));
#else
# ifdef __GNUC__
int _EXFUN(strerror_r,(int, char *, size_t)) __asm__ ("__xpg_strerror_r");
# else
int _EXFUN(__xpg_strerror_r,(int, char *, size_t));
# define strerror_r __xpg_strerror_r
# endif
#endif
size_t _EXFUN(strlcat,(char *, const char *, size_t));
size_t _EXFUN(strlcpy,(char *, const char *, size_t));
int _EXFUN(strncasecmp,(const char *, const char *, size_t));

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@ -71,7 +71,8 @@ GENERAL_SOURCES = \
wmemcmp.c \
wmemcpy.c \
wmemmove.c \
wmemset.c
wmemset.c \
xpg_strerror_r.c
if ELIX_LEVEL_1
ELIX_2_SOURCES =

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@ -88,7 +88,7 @@ am__objects_1 = lib_a-bcopy.$(OBJEXT) lib_a-bzero.$(OBJEXT) \
lib_a-wcsxfrm.$(OBJEXT) lib_a-wcwidth.$(OBJEXT) \
lib_a-wmemchr.$(OBJEXT) lib_a-wmemcmp.$(OBJEXT) \
lib_a-wmemcpy.$(OBJEXT) lib_a-wmemmove.$(OBJEXT) \
lib_a-wmemset.$(OBJEXT)
lib_a-wmemset.$(OBJEXT) lib_a-xpg_strerror_r.$(OBJEXT)
@ELIX_LEVEL_1_FALSE@am__objects_2 = lib_a-bcmp.$(OBJEXT) \
@ELIX_LEVEL_1_FALSE@ lib_a-memccpy.$(OBJEXT) \
@ELIX_LEVEL_1_FALSE@ lib_a-mempcpy.$(OBJEXT) \
@ -120,7 +120,7 @@ am__objects_4 = bcopy.lo bzero.lo index.lo memchr.lo memcmp.lo \
wcslcpy.lo wcslen.lo wcsncat.lo wcsncmp.lo wcsncpy.lo \
wcsnlen.lo wcspbrk.lo wcsrchr.lo wcsspn.lo wcsstr.lo wcstok.lo \
wcswidth.lo wcsxfrm.lo wcwidth.lo wmemchr.lo wmemcmp.lo \
wmemcpy.lo wmemmove.lo wmemset.lo
wmemcpy.lo wmemmove.lo wmemset.lo xpg_strerror_r.lo
@ELIX_LEVEL_1_FALSE@am__objects_5 = bcmp.lo memccpy.lo mempcpy.lo \
@ELIX_LEVEL_1_FALSE@ stpcpy.lo stpncpy.lo strndup.lo \
@ELIX_LEVEL_1_FALSE@ strcasestr.lo strndup_r.lo wcpcpy.lo \
@ -215,6 +215,7 @@ MKDIR_P = @MKDIR_P@
NEWLIB_CFLAGS = @NEWLIB_CFLAGS@
NM = @NM@
NMEDIT = @NMEDIT@
NO_INCLUDE_LIST = @NO_INCLUDE_LIST@
OBJDUMP = @OBJDUMP@
OBJEXT = @OBJEXT@
OTOOL = @OTOOL@
@ -363,7 +364,8 @@ GENERAL_SOURCES = \
wmemcmp.c \
wmemcpy.c \
wmemmove.c \
wmemset.c
wmemset.c \
xpg_strerror_r.c
@ELIX_LEVEL_1_FALSE@ELIX_2_SOURCES = \
@ELIX_LEVEL_1_FALSE@ bcmp.c \
@ -887,6 +889,12 @@ lib_a-wmemset.o: wmemset.c
lib_a-wmemset.obj: wmemset.c
$(CC) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(AM_CPPFLAGS) $(CPPFLAGS) $(lib_a_CFLAGS) $(CFLAGS) -c -o lib_a-wmemset.obj `if test -f 'wmemset.c'; then $(CYGPATH_W) 'wmemset.c'; else $(CYGPATH_W) '$(srcdir)/wmemset.c'; fi`
lib_a-xpg_strerror_r.o: xpg_strerror_r.c
$(CC) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(AM_CPPFLAGS) $(CPPFLAGS) $(lib_a_CFLAGS) $(CFLAGS) -c -o lib_a-xpg_strerror_r.o `test -f 'xpg_strerror_r.c' || echo '$(srcdir)/'`xpg_strerror_r.c
lib_a-xpg_strerror_r.obj: xpg_strerror_r.c
$(CC) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(AM_CPPFLAGS) $(CPPFLAGS) $(lib_a_CFLAGS) $(CFLAGS) -c -o lib_a-xpg_strerror_r.obj `if test -f 'xpg_strerror_r.c'; then $(CYGPATH_W) 'xpg_strerror_r.c'; else $(CYGPATH_W) '$(srcdir)/xpg_strerror_r.c'; fi`
lib_a-bcmp.o: bcmp.c
$(CC) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(AM_CPPFLAGS) $(CPPFLAGS) $(lib_a_CFLAGS) $(CFLAGS) -c -o lib_a-bcmp.o `test -f 'bcmp.c' || echo '$(srcdir)/'`bcmp.c

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@ -301,6 +301,17 @@ declares that subsequent calls to <<strerror>> may overwrite the
result string; therefore portable code cannot depend on the reentrancy
of this subroutine.
Although this implementation of <<strerror>> guarantees a non-null
result with a NUL-terminator, some implementations return <<NULL>>
on failure. Although POSIX allows <<strerror>> to set <<errno>>
to EINVAL on failure, this implementation does not do so (unless
you provide <<_user_strerror>>).
POSIX recommends that unknown <[errnum]> result in a message
including that value, however it is not a requirement and this
implementation does not provide that information (unless you
provide <<_user_strerror>>).
This implementation of <<strerror>> provides for user-defined
extensibility. <<errno.h>> defines <[__ELASTERROR]>, which can be
used as a base for user-defined error values. If the user supplies a
@ -313,6 +324,9 @@ character pointer. If <[errnum]> is unknown to <<_user_strerror>>,
<<_user_strerror>> returns <[NULL]>. The default <<_user_strerror>>
returns <[NULL]> for all input values.
Note that <<_user_sterror>> must be thread-safe and not alter <<errno>>
if <<strerror_r>> is to comply with POSIX.
<<strerror>> requires no supporting OS subroutines.
QUICKREF

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@ -1,3 +1,4 @@
/* GNU variant of strerror_r. */
/*
FUNCTION
<<strerror_r>>---convert error number to string and copy to buffer
@ -7,7 +8,11 @@ INDEX
ANSI_SYNOPSIS
#include <string.h>
#ifdef _GNU_SOURCE
char *strerror_r(int <[errnum]>, char *<[buffer]>, size_t <[n]>);
#else
int strerror_r(int <[errnum]>, char *<[buffer]>, size_t <[n]>);
#endif
TRAD_SYNOPSIS
#include <string.h>
@ -26,28 +31,53 @@ error number, the result is the empty string.
See <<strerror>> for how strings are mapped to <<errnum>>.
RETURNS
This function returns a pointer to a string. Your application must
not modify that string.
There are two variants: the GNU version always returns a NUL-terminated
string, which is <[buffer]> if all went well, but which is another
pointer if <[n]> was too small (leaving <[buffer]> untouched). If the
return is not <[buffer]>, your application must not modify that string.
The POSIX version returns 0 on success, <[EINVAL]> if <<errnum>> was not
recognized, and <[ERANGE]> if <[n]> was too small. The variant chosen
depends on macros that you define before inclusion of <<string.h>>.
PORTABILITY
<<strerror_r>> is a GNU extension.
<<strerror_r>> with a <[char *]> result is a GNU extension.
<<strerror_r>> with an <[int]> result is required by POSIX 2001.
This function is compliant only if <<_user_strerror>> is not provided,
or if it is thread-safe and does not modify <<errno>>.
POSIX states that the contents of <[buf]> are unspecified on error,
although this implementation guarantees a NUL-terminated string for
all except <[n]> of 0.
POSIX recommends that unknown <[errnum]> result in a message including
that value, however it is not a requirement and this implementation
provides only an empty string (unless you provide <<_user_strerror>>).
POSIX also recommends that unknown <[errnum]> fail with EINVAL even
when providing such a message, however it is not a requirement and
this implementation will return success if <<_user_strerror>> provided
a non-empty alternate string.
<<strerror_r>> requires no supporting OS subroutines.
*/
#undef __STRICT_ANSI__
#define _GNU_SOURCE
#include <errno.h>
#include <string.h>
#undef strerror_r
/* For backwards-compatible linking, this must be the GNU signature;
see xpg_strerror_r.c for the POSIX version. */
char *
_DEFUN (strerror_r, (errnum, buffer, n),
int errnum _AND
char *buffer _AND
size_t n)
{
char *error;
error = strerror (errnum);
char *error = strerror (errnum);
return strncpy (buffer, (const char *)error, n);
if (strlen (error) >= n)
return error;
return strcpy (buffer, error);
}

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@ -0,0 +1,25 @@
/* POSIX variant of strerror_r. */
#undef __STRICT_ANSI__
#include <errno.h>
#include <string.h>
int
_DEFUN (__xpg_strerror_r, (errnum, buffer, n),
int errnum _AND
char *buffer _AND
size_t n)
{
char *error;
if (!n)
return ERANGE;
error = strerror (errnum);
if (strlen (error) >= n)
{
memcpy (buffer, error, n - 1);
buffer[n - 1] = '\0';
return ERANGE;
}
strcpy (buffer, error);
return *error ? 0 : EINVAL;
}