aboutsummaryrefslogtreecommitdiff
diff options
context:
space:
mode:
authorSiddhesh Poyarekar <siddhesh@sourceware.org>2016-06-24 01:58:44 +0530
committerSiddhesh Poyarekar <siddhesh@sourceware.org>2016-06-24 02:00:12 +0530
commitd7e64365fea8d9223a233487de1e1d6e3d21c553 (patch)
tree89d9c80d11b8bf0c240b6aa3a1439e49123f6f6f
parentdb3476aff19b75c4fdefbe65fcd5f0a90588ba51 (diff)
downloadglibc-d7e64365fea8d9223a233487de1e1d6e3d21c553.zip
glibc-d7e64365fea8d9223a233487de1e1d6e3d21c553.tar.gz
glibc-d7e64365fea8d9223a233487de1e1d6e3d21c553.tar.bz2
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.
-rw-r--r--ChangeLog6
-rw-r--r--posix/getconf.c84
2 files changed, 66 insertions, 24 deletions
diff --git a/ChangeLog b/ChangeLog
index ce5070f..66bb323 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -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]
diff --git a/posix/getconf.c b/posix/getconf.c
index 3e03396..5a65df8 100644
--- a/posix/getconf.c
+++ b/posix/getconf.c
@@ -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)
{