Re: glibc 2.3 pthread patch

[Alexandre Julliard]

Ove Kaaven  writes:
> Now that glibc 2.3 is available for those bleeding-edge folks on debian
> unstable, it seems that Wines compiled on 2.2 won't run on 2.3 systems.
> The glibc folks did warn us about this a while ago though, so here's a
> patch that implements their suggestion for making wine compatible with as
> many glibc versions as possible. Perhaps Alexandre wants to use his
> WINE_GET_SONAME stuff to detect the name of the libc at configure time
> instead of at runtime like I do, though.

Funny, I was working on the same thing right now... But do you really
need to fetch the real libc handle?  It seems to me RTLD_NEXT should
be enough. Here's how I did it:

Index: scheduler/pthread.c
===================================================================
RCS file: /opt/cvs-commit/wine/scheduler/pthread.c,v
retrieving revision 1.26
diff -u -r1.26 pthread.c
--- scheduler/pthread.c	12 Sep 2002 22:07:06 -0000	1.26
+++ scheduler/pthread.c	20 Oct 2002 21:45:13 -0000
@@ -38,13 +38,6 @@
 #include "thread.h"
 #include "winternl.h"

-static int init_done;
-
-void PTHREAD_init_done(void)
-{
-    init_done = 1;
-}
-
 /* Currently this probably works only for glibc2,
  * which checks for the presence of double-underscore-prepended
  * pthread primitives, and use them if available.
@@ -62,28 +55,18 @@
  asm(".globl " PSTR(alias) "\n" \
      "\t.set " PSTR(alias) "," PSTR(orig))

-/* strong_alias does not work on external symbols (.o format limitation?),
- * so for those, we need to use the pogo stick */
-#if defined(__i386__) && !defined(__PIC__)
-/* FIXME: PIC */
-#define jump_alias(orig, alias) __ASM_GLOBAL_FUNC( alias, "jmp " PSTR(orig))
-#endif
+static int init_done;

-/* get necessary libc symbols */
-#if (__GLIBC__ == 2) && (__GLIBC_MINOR__ >= 1) && defined(HAVE___LIBC_FORK)
-#define LIBC_FORK __libc_fork
-#define PTHREAD_FORK __fork
-#define ALIAS_FORK
-#else
-#define LIBC_FORK __fork
-#define PTHREAD_FORK fork
-#endif
-extern pid_t LIBC_FORK(void);
+static pid_t (*libc_fork)(void);
+static int (*libc_sigaction)(int signum, const struct sigaction *act, struct sigaction *oldact);
+
+void PTHREAD_init_done(void)
+{
+    init_done = 1;
+    if (!libc_fork) libc_fork = dlsym( RTLD_NEXT, "fork" );
+    if (!libc_sigaction) libc_sigaction = dlsym( RTLD_NEXT, "sigaction" );
+}

-#define LIBC_SIGACTION __sigaction
-extern int LIBC_SIGACTION(int signum,
-                         const struct sigaction *act,
-                         struct sigaction *oldact);

/* NOTE: This is a truly extremely incredibly ugly hack!
  * But it does seem to work... */
@@ -255,15 +238,20 @@
 }
 strong_alias(__pthread_atfork, pthread_atfork);

-pid_t PTHREAD_FORK(void)
+pid_t __fork(void)
 {
     pid_t pid;
     int i;

+    if (!libc_fork)
+    {
+        libc_fork = dlsym( RTLD_NEXT, "fork" );
+        assert( libc_fork );
+    }
     EnterCriticalSection( &atfork_section );
     /* prepare handlers are called in reverse insertion order */
     for (i = atfork_count - 1; i >= 0; i--) if (atfork_prepare[i]) atfork_prepare[i]();
-    if (!(pid = LIBC_FORK()))
+    if (!(pid = libc_fork()))
     {
         InitializeCriticalSection( &atfork_section );
         for (i = 0; i < atfork_count; i++) if (atfork_child[i]) atfork_child[i]();
@@ -275,9 +263,7 @@
     }
     return pid;
 }
-#ifdef ALIAS_FORK
-strong_alias(PTHREAD_FORK, fork);
-#endif
+strong_alias(__fork, fork);

/***** MUTEXES *****/

@@ -658,13 +644,20 @@
 /***** ANTI-OVERRIDES *****/
 /* pthreads tries to override these, point them back to libc */

-#ifdef jump_alias
-jump_alias(LIBC_SIGACTION, sigaction);
-#else
 int sigaction(int signum, const struct sigaction *act, struct sigaction *oldact)
 {
-  return LIBC_SIGACTION(signum, act, oldact);
+    if (!libc_sigaction)
+    {
+        libc_sigaction = dlsym( RTLD_NEXT, "sigaction" );
+        assert( libc_sigaction );
+    }
+    return libc_sigaction(signum, act, oldact);
+}
+
+#else /* __GLIBC__ */
+
+void PTHREAD_init_done(void)
+{
 }
-#endif

#endif /* __GLIBC__ */