FreeTDS Development Group

["Castellano, Nicholas" <Nicholas_Castellano AT acml.com>]

Can you try this patch?  It uses a pthread mutex to ensure that only one
thread at a time executes inside the vasprintf() code.  I can't test this on
my system right now (my only box with pthreads is DU4.0d, and I'm unable to
compile src/tds/threadsafe.c when _REENTRANT is defined...I'll address that
problem later on)

--nick

-----Original Message-----
From: bounce-freetds-145195 AT franklin.oit.unc.edu
[mailto:bounce-freetds-145195 AT franklin.oit.unc.edu] 
Sent: Tuesday, August 27, 2002 6:10 AM
To: TDS Development Group
Subject: [freetds] asprintf vasprintf


These function aren't reentrant, so they cause problem with multithread
environment (watch env variable...).

A solution should use SA_SIGINFO flag in sigaction. Is SA_SIGINFO flag
portable ?

freddy77


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Index: asprintf.c
===================================================================
RCS file: /cvsroot/freetds/freetds/src/tds/asprintf.c,v
retrieving revision 1.2
diff -u -r1.2 asprintf.c
--- asprintf.c  23 Aug 2002 13:10:15 -0000      1.2
+++ asprintf.c  27 Aug 2002 16:15:49 -0000
@@ -18,10 +18,34 @@
 #include <signal.h>
 #include <assert.h>
 #include <string.h>
+#ifdef _REENTRANT
+#include <pthread.h>
+#endif
 
 static char  software_version[]   = "$Id: asprintf.c,v 1.2 2002/08/23 
13:10:15 freddy77 Exp $";
 static void *no_unused_var_warn[] = {software_version,
                                      no_unused_var_warn};
+
+#ifdef _REENTRANT
+static pthread_mutex_t mutex = PTHREAD_MUTEX_INITIALIZER;
+#endif
+
+static void
+mutex_lock(void)
+{
+#ifdef _REENTRANT
+  pthread_mutex_lock(&mutex);
+#endif
+}
+
+static void
+mutex_unlock(void)
+{
+#ifdef _REENTRANT
+  pthread_mutex_unlock(&mutex);
+#endif
+}
+
 static jmp_buf env;
 
 static void
@@ -39,9 +63,11 @@
   int len;
   long pgsize = sysconf(_SC_PAGE_SIZE);
 
+  mutex_lock();
   pgs = ((strlen(fmt) + 1) / pgsize) + 1;
   if (sigaction(SIGSEGV, NULL, &osa)) {
     *ret = NULL;
+    mutex_unlock();
     return -1;
   }
   sa.sa_handler = sigsegv;
@@ -54,12 +80,14 @@
   }
   if ((buf = valloc((pgs + 1) * pgsize)) == NULL) {
     *ret = NULL;
+    mutex_unlock();
     return -1;
   }
   assert(((unsigned long) buf % pgsize) == 0);
   if (sigaction(SIGSEGV, &sa, NULL)) {
     free((void *) buf);
     *ret = NULL;
+    mutex_unlock();
     return -1;
   }
   mprotect((void *) (buf + pgs * pgsize), pgsize, PROT_NONE);
@@ -68,18 +96,22 @@
   if (sigaction(SIGSEGV, &osa, NULL)) {
     free((void *) buf);
     *ret = NULL;
+    mutex_unlock();
     return -1;
   }
   if (len < 0) {
     free((void *) buf);
     *ret = NULL;
+    mutex_unlock();
     return len;
   }
   if ((buf = realloc((void *) buf, len + 1)) == NULL) {
     *ret = NULL;
+    mutex_unlock();
     return -1;
   }
   *ret = (char *) buf;
+  mutex_unlock();
   return len;
 }