[SCM] an open source computer algebra system branch, cleanedupstream, updated. 6125e540ca6d66c307958938a9d53b245507c323

[Bernhard R. Link]

The following commit has been merged in the cleanedupstream branch:
commit 53a255a0daff08e321445d218ece1095a1d64da6
Author: Hans Schoenemann <hannes at mathematik.uni-kl.de>
Date:   Mon Mar 12 10:35:12 2012 +0100

    fix: check args for semaphore stuff, fix return values

diff --git a/Singular/semaphore.c b/Singular/semaphore.c
index 1a4dc7f..dba6e08 100644
--- a/Singular/semaphore.c
+++ b/Singular/semaphore.c
@@ -14,14 +14,19 @@
 
 static sem_t *semaphore[SIPC_MAX_SEMAPHORES];
 
-int sipc_semaphore_init(int id, int count) {
+/* return 1 on success,
+ *        0 if already initialized,
+ *       -1 for errors
+ */
+int sipc_semaphore_init(int id, int count)
+{
   char buf[100];
   sem_t *sem;
-  if (id >= SIPC_MAX_SEMAPHORES)
-    return 0;
+  if ((id<0) || (id >= SIPC_MAX_SEMAPHORES))
+    return -1;
   // Already initialized?
   if (semaphore[id])
-    return 1;
+    return 0;
   // to make it completely safe, we should generate a name
   // from /dev/urandom.
 #if USE_SEM_INIT
@@ -29,11 +34,11 @@ int sipc_semaphore_init(int id, int count) {
   // can keep using the semaphore after fork + exec.
   sem = malloc(sizeof(sem_t));
   if (!sem)
-    return 0;
+    return -1;
   if (sem_init(sem, 1, count) < 0)
   {
     free(sem);
-    return 0;
+    return -1;
   }
 #else
   sprintf(buf, "/%d:sem%d", getpid(), id);
@@ -41,7 +46,7 @@ int sipc_semaphore_init(int id, int count) {
   sem = sem_open(buf, O_CREAT, 0600, count);
 #endif
   if (sem == SEM_FAILED || !sem)
-    return 0;
+    return -1;
   semaphore[id] = sem;
 #if !USE_SEM_INIT
   sem_unlink(buf);
@@ -49,24 +54,36 @@ int sipc_semaphore_init(int id, int count) {
   return 1;
 }
 
-int sipc_semaphore_exists(int id) {
+int sipc_semaphore_exists(int id)
+{
+  if ((id<0) || (id >= SIPC_MAX_SEMAPHORES))  return -1;
   return semaphore[id] != NULL;
 }
 
-void sipc_semaphore_acquire(int id) {
+int sipc_semaphore_acquire(int id)
+{
+  if ((id<0) || (id >= SIPC_MAX_SEMAPHORES))  return -1;
   sem_wait(semaphore[id]);
+  return 1;
 }
 
-int sipc_semaphore_try_acquire(int id) {
+int sipc_semaphore_try_acquire(int id)
+{
+  if ((id<0) || (id >= SIPC_MAX_SEMAPHORES))  return -1;
   return !sem_trywait(semaphore[id]);
 }
 
-void sipc_semaphore_release(int id) {
+int sipc_semaphore_release(int id)
+{
+  if ((id<0) || (id >= SIPC_MAX_SEMAPHORES))  return -1;
   sem_post(semaphore[id]);
+  return 1;
 }
 
-int sipc_semaphore_get_value(int id) {
+int sipc_semaphore_get_value(int id)
+{
   int val;
+  if ((id<0) || (id >= SIPC_MAX_SEMAPHORES))  return -1;
   sem_getvalue(semaphore[id], &val);
   return val;
 }
@@ -78,13 +95,13 @@ int simpleipc_cmd(char *cmd, int id, int v)
   else if (strcmp(cmd,"exists")==0)
     return sipc_semaphore_exists(id);
   else if (strcmp(cmd,"acquire")==0)
-    {  sipc_semaphore_acquire(id); return -2;}
+    return  sipc_semaphore_acquire(id);
   else if (strcmp(cmd,"try_acquire")==0)
     return sipc_semaphore_try_acquire(id);
   else if (strcmp(cmd,"release")==0)
-    { sipc_semaphore_release(id); return -2;}
+    return sipc_semaphore_release(id);
   else if (strcmp(cmd,"get_value")==0)
-    { return sipc_semaphore_get_value(id); }
+    return sipc_semaphore_get_value(id);
   else printf("unknown\n");
     return  -2;
 }

-- 
an open source computer algebra system