Attachment 10003 Details for Bug 10640 – Proposed patch for master

[patch] Proposed patch for master

0001-lib-tevent-make-TEVENT_SIG_INCREMENT-atomic.patch (text/plain), 3.70 KB, created by Jeremy Allison on 2014-06-03 17:48:53 UTC

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Creator: Jeremy Allison

Created: 2014-06-03 17:48:53 UTC

Size: 3.70 KB

patch

obsolete

>From 0bd67bbfbccb7a2a2212276454e60214d637370b Mon Sep 17 00:00:00 2001
>From: Jeremy Allison <jra@samba.org>
>Date: Tue, 3 Jun 2014 10:44:19 -0700
>Subject: [PATCH] lib: tevent: make TEVENT_SIG_INCREMENT atomic.
>
>On arm platforms incrementing a variable is not
>an atomic operation, so may be interrupted by
>signal processing (if a signal interrups another
>signal handler).
>
>Use compiler built-ins to make this atomic.
>__sync_fetch_and_add() works on gcc, llvm,
>IBM xlC on AIX, and Intel icc (10.1 and
>above).
>
>atomic_add_32() works on Oracle Solaris.
>
>Based on an inital patch from kamei@osstech.co.jp.
>
>Bug #10640 - smbd is not responding - tevent_common_signal_handler() increments non-atomic variables
>
>https://bugzilla.samba.org/show_bug.cgi?id=10640
>
>Signed-off-by: Jeremy Allison <jra@samba.org>
>---
> lib/replace/replace.h      |  5 +++++
> lib/replace/wscript        | 25 +++++++++++++++++++++++++
> lib/tevent/tevent_signal.c |  6 ++++++
> 3 files changed, 36 insertions(+)
>
>diff --git a/lib/replace/replace.h b/lib/replace/replace.h
>index f940898..bc40bf0 100644
>--- a/lib/replace/replace.h
>+++ b/lib/replace/replace.h
>@@ -904,4 +904,9 @@ bool nss_wrapper_hosts_enabled(void);
> bool socket_wrapper_enabled(void);
> bool uid_wrapper_enabled(void);
> 
>+/* Needed for Solaris atomic_add_XX functions. */
>+#if defined(HAVE_SYS_ATOMIC_H)
>+#include <sys/atomic.h>
>+#endif
>+
> #endif /* _LIBREPLACE_REPLACE_H */
>diff --git a/lib/replace/wscript b/lib/replace/wscript
>index a26de0f..22dd132 100644
>--- a/lib/replace/wscript
>+++ b/lib/replace/wscript
>@@ -110,6 +110,7 @@ struct foo bar = { .y = 'X', .x = 1 };
>     conf.CHECK_HEADERS('sys/extattr.h sys/ea.h sys/proplist.h sys/cdefs.h')
>     conf.CHECK_HEADERS('utmp.h utmpx.h lastlog.h malloc.h')
>     conf.CHECK_HEADERS('syscall.h sys/syscall.h inttypes.h')
>+    conf.CHECK_HEADERS('sys/atomic.h')
> 
>     # Check for process set name support
>     conf.CHECK_CODE('''
>@@ -229,6 +230,30 @@ struct foo bar = { .y = 'X', .x = 1 };
>                        msg="Checking whether we have ucontext_t",
>                        headers='signal.h sys/ucontext.h')
> 
>+    # Check for atomic builtins. */
>+    conf.CHECK_CODE('''
>+                    int main(void) {
>+                        int i;
>+                        (void)__sync_fetch_and_add(&i, 1);
>+                        return 0;
>+                    }
>+                    ''',
>+                    'HAVE___SYNC_FETCH_AND_ADD',
>+                    msg='Checking for __sync_fetch_and_add compiler builtin')
>+
>+    conf.CHECK_CODE('''
>+                    #include <stdint.h>
>+                    #include <sys/atomic.h>
>+                    int main(void) {
>+                        int32_t i;
>+                        atomic_add_32(&i, 1);
>+                        return 0;
>+                    }
>+                    ''',
>+                    'HAVE_ATOMIC_ADD_32',
>+                    headers='stdint.h sys/atomic.h',
>+                    msg='Checking for atomic_add_32 compiler builtin')
>+
>     # these may be builtins, so we need the link=False strategy
>     conf.CHECK_FUNCS('strdup memmem printf memset memcpy memmove strcpy strncpy bzero', link=False)
> 
>diff --git a/lib/tevent/tevent_signal.c b/lib/tevent/tevent_signal.c
>index 1ff4872..b54da2e 100644
>--- a/lib/tevent/tevent_signal.c
>+++ b/lib/tevent/tevent_signal.c
>@@ -52,7 +52,13 @@ struct tevent_sigcounter {
> 	uint32_t seen;
> };
> 
>+#if defined(HAVE___SYNC_FETCH_AND_ADD)
>+#define TEVENT_SIG_INCREMENT(s) __sync_fetch_and_add(&((s).count), 1)
>+#elif defined(HAVE_ATOMIC_ADD_32)
>+#define TEVENT_SIG_INCREMENT(s) atomic_add_32(&((s).count), 1)
>+#else
> #define TEVENT_SIG_INCREMENT(s) (s).count++
>+#endif
> #define TEVENT_SIG_SEEN(s, n) (s).seen += (n)
> #define TEVENT_SIG_PENDING(s) ((s).seen != (s).count)
> 
>-- 
>1.9.1.423.g4596e3a
>

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