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Avoid attempt for runtime checks if all environments are defined 

getconf has the capability to do a runtime check for environment
support in cases where there is optional support for an environment
(_POSIX_V7_ILP32_OFF32 on x86_64 for example) and this is indicated by
not defining the _POSIX_V7_ILP32_OFF32 macro, which results in getconf
doing an additional execve of _POSIX_V7_ILP32_OFF32 in the
$GETCONF_DIR.

The default bits/environments.h however does not leave any environment
macros undefined, which means that no such additional execve is
needed.  gcc trunk catches this as a build failure since it finds that
the code block inside switch(specs[i].num) is not reachable.  Avoid
this error by not bothering about the additional exec (and looking in
specific environments) when all environments are defined.

Tested on aarch64.

	* posix/getconf.c: Define ALL_ENVIRONMENTS_DEFINED if all
	environment macros are defined.
	(main): Avoid execve if ALL_ENVIRONMENTS_DEFINED is defined.
This commit is contained in:
Siddhesh Poyarekar 2016-06-24 01:58:44 +05:30
parent db3476aff1
commit d7e64365fe
2 changed files with 66 additions and 24 deletions
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6
ChangeLog
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@ -1,3 +1,9 @@
2016-06-23 Siddhesh Poyarekar <siddhesh@sourceware.org>
* posix/getconf.c: Define ALL_ENVIRONMENTS_DEFINED if all
environment macros are defined.
(main): Avoid execve if ALL_ENVIRONMENTS_DEFINED is defined.
2016-06-23 Florian Weimer <fweimer@redhat.com>
[BZ #20191]

84
posix/getconf.c
View File

@ -29,6 +29,23 @@
#define NEED_SPEC_ARRAY 1
#include <posix-conf-vars.h>
/* If all of the environments are defined in environments.h, then we don't need
to bother with doing a runtime check for a specific environment. */
#if (defined _SC_V6_ILP32_OFF32 \
&& defined _SC_V7_LPBIG_OFFBIG \
&& defined _SC_XBS5_LP64_OFF64 \
&& defined _SC_V6_LP64_OFF64 \
&& defined _SC_V7_ILP32_OFFBIG \
&& defined _SC_V6_LPBIG_OFFBIG \
&& defined _SC_V7_LP64_OFF64 \
&& defined _SC_V7_ILP32_OFF32 \
&& defined _SC_XBS5_LPBIG_OFFBIG \
&& defined _SC_XBS5_ILP32_OFFBIG \
&& defined _SC_V6_ILP32_OFFBIG \
&& defined _SC_XBS5_ILP32_OFF32)
# define ALL_ENVIRONMENTS_DEFINED 1
#endif
struct conf
{
const char *name;
@ -488,6 +505,24 @@ environment SPEC.\n\n"));
return 0;
}
#ifdef ALL_ENVIRONMENTS_DEFINED
if (argc > 1 && strncmp (argv[1], "-v", 2) == 0)
{
if (argv[1][2] == '\0')
{
if (argc < 3)
usage ();
argv += 2;
argc -= 2;
}
else
{
argv += 1;
argc += 1;
}
}
#else
const char *getconf_dir = getenv ("GETCONF_DIR") ?: GETCONF_DIR;
size_t getconf_dirlen = strlen (getconf_dir);
@ -538,42 +573,42 @@ environment SPEC.\n\n"));
switch (specs[i].num)
{
#ifndef _XBS5_ILP32_OFF32
# ifndef _XBS5_ILP32_OFF32
case _SC_XBS5_ILP32_OFF32:
#endif
#ifndef _XBS5_ILP32_OFFBIG
# endif
# ifndef _XBS5_ILP32_OFFBIG
case _SC_XBS5_ILP32_OFFBIG:
#endif
#ifndef _XBS5_LP64_OFF64
# endif
# ifndef _XBS5_LP64_OFF64
case _SC_XBS5_LP64_OFF64:
#endif
#ifndef _XBS5_LPBIG_OFFBIG
# endif
# ifndef _XBS5_LPBIG_OFFBIG
case _SC_XBS5_LPBIG_OFFBIG:
#endif
#ifndef _POSIX_V6_ILP32_OFF32
# endif
# ifndef _POSIX_V6_ILP32_OFF32
case _SC_V6_ILP32_OFF32:
#endif
#ifndef _POSIX_V6_ILP32_OFFBIG
# endif
# ifndef _POSIX_V6_ILP32_OFFBIG
case _SC_V6_ILP32_OFFBIG:
#endif
#ifndef _POSIX_V6_LP64_OFF64
# endif
# ifndef _POSIX_V6_LP64_OFF64
case _SC_V6_LP64_OFF64:
#endif
#ifndef _POSIX_V6_LPBIG_OFFBIG
# endif
# ifndef _POSIX_V6_LPBIG_OFFBIG
case _SC_V6_LPBIG_OFFBIG:
#endif
#ifndef _POSIX_V7_ILP32_OFF32
# endif
# ifndef _POSIX_V7_ILP32_OFF32
case _SC_V7_ILP32_OFF32:
#endif
#ifndef _POSIX_V7_ILP32_OFFBIG
# endif
# ifndef _POSIX_V7_ILP32_OFFBIG
case _SC_V7_ILP32_OFFBIG:
#endif
#ifndef _POSIX_V7_LP64_OFF64
# endif
# ifndef _POSIX_V7_LP64_OFF64
case _SC_V7_LP64_OFF64:
#endif
#ifndef _POSIX_V7_LPBIG_OFFBIG
# endif
# ifndef _POSIX_V7_LPBIG_OFFBIG
case _SC_V7_LPBIG_OFFBIG:
#endif
# endif
{
const char *args[argc + 3];
size_t spec_len = strlen (spec);
@ -592,6 +627,7 @@ environment SPEC.\n\n"));
break;
}
}
#endif
if (argc > 1 && strcmp (argv[1], "-a") == 0)
{