* [PATCH] Avoid attempt for runtime checks if all environments are defined
@ 2016-06-23 17:30 Siddhesh Poyarekar
2016-06-23 19:35 ` Mike Frysinger
0 siblings, 1 reply; 4+ messages in thread
From: Siddhesh Poyarekar @ 2016-06-23 17:30 UTC (permalink / raw)
To: libc-alpha
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 additiona 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.
---
posix/getconf.c | 84 ++++++++++++++++++++++++++++++++++++++++-----------------
1 file changed, 60 insertions(+), 24 deletions(-)
diff --git a/posix/getconf.c b/posix/getconf.c
index 3e03396..7880446 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)
{
--
2.5.5
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [PATCH] Avoid attempt for runtime checks if all environments are defined
2016-06-23 17:30 [PATCH] Avoid attempt for runtime checks if all environments are defined Siddhesh Poyarekar
@ 2016-06-23 19:35 ` Mike Frysinger
2016-06-23 20:32 ` Siddhesh Poyarekar
0 siblings, 1 reply; 4+ messages in thread
From: Mike Frysinger @ 2016-06-23 19:35 UTC (permalink / raw)
To: Siddhesh Poyarekar; +Cc: libc-alpha
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On 23 Jun 2016 23:00, Siddhesh Poyarekar wrote:
> macros undefined, which means that no such additiona execve is needed
"additional"
> + #define ALL_ENVIRONMENTS_DEFINED 1
don't indent the #
-mike
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^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] Avoid attempt for runtime checks if all environments are defined
2016-06-23 19:35 ` Mike Frysinger
@ 2016-06-23 20:32 ` Siddhesh Poyarekar
2016-08-05 15:09 ` Maciej W. Rozycki
0 siblings, 1 reply; 4+ messages in thread
From: Siddhesh Poyarekar @ 2016-06-23 20:32 UTC (permalink / raw)
To: libc-alpha
On Thu, Jun 23, 2016 at 03:35:50PM -0400, Mike Frysinger wrote:
> On 23 Jun 2016 23:00, Siddhesh Poyarekar wrote:
> > macros undefined, which means that no such additiona execve is needed
>
> "additional"
>
> > + #define ALL_ENVIRONMENTS_DEFINED 1
>
> don't indent the #
Thanks, pushed with those changes.
Siddhesh
From d7e64365fea8d9223a233487de1e1d6e3d21c553 Mon Sep 17 00:00:00 2001
From: Siddhesh Poyarekar <siddhesh@sourceware.org>
Date: Fri, 24 Jun 2016 01:58:44 +0530
Subject: [PATCH] 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.
---
ChangeLog | 6 +++++
posix/getconf.c | 84 ++++++++++++++++++++++++++++++++++++++++-----------------
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)
{
--
2.5.5
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [PATCH] Avoid attempt for runtime checks if all environments are defined
2016-06-23 20:32 ` Siddhesh Poyarekar
@ 2016-08-05 15:09 ` Maciej W. Rozycki
0 siblings, 0 replies; 4+ messages in thread
From: Maciej W. Rozycki @ 2016-08-05 15:09 UTC (permalink / raw)
To: Siddhesh Poyarekar; +Cc: libc-alpha
On Thu, 23 Jun 2016, Siddhesh Poyarekar wrote:
> > > macros undefined, which means that no such additiona execve is needed
> >
> > "additional"
> >
> > > + #define ALL_ENVIRONMENTS_DEFINED 1
> >
> > don't indent the #
>
> Thanks, pushed with those changes.
This broke `mips-linux-gnu' compilation with GCC 6:
In file included from ./posix-conf-vars.h:30:0,
from getconf.c:30:
.../posix/posix-conf-vars-def.h:999:21: error: 'nspecs' defined but not used [-Werror=unused-const-variable]
static const size_t nspecs = sizeof (specs) / sizeof (specs[0]);
^~~~~~
cc1: all warnings being treated as errors
make[2]: *** [.../posix/getconf.o] Error 1
-- it looks to me like you'd need to define NEED_SPEC_ARRAY to 0 if
setting ALL_ENVIRONMENTS_DEFINED (but then it looks like a chicken-and-egg
problem to me requiring a solution more complex than just fiddling with
NEED_SPEC_ARRAY, so I'm leaving it up to you to sort out).
Maciej
^ permalink raw reply [flat|nested] 4+ messages in thread
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2016-06-23 17:30 [PATCH] Avoid attempt for runtime checks if all environments are defined Siddhesh Poyarekar
2016-06-23 19:35 ` Mike Frysinger
2016-06-23 20:32 ` Siddhesh Poyarekar
2016-08-05 15:09 ` Maciej W. Rozycki
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