X-Git-Url: http://git.tuebingen.mpg.de/?p=dss.git;a=blobdiff_plain;f=ipc.c;h=183c76e9b4ad0b46ee2910207f12626fbb7087ca;hp=65ef20049d26748ef54b6fd60068e7492b159beb;hb=5b1c780d1a3e02a6f64242ef5d8c0a2dc71de3ec;hpb=f33cf243ae1cb5657cccb7c43c99093936093b4a

diff --git a/ipc.c b/ipc.c
index 65ef200..183c76e 100644
--- a/ipc.c
+++ b/ipc.c
@@ -13,6 +13,7 @@
 #include <stddef.h>
 #include <limits.h>
 #include <sys/param.h>
+#include <stdbool.h>
 
 #include "gcc-compat.h"
 #include "str.h"
@@ -227,7 +228,7 @@ error:
 	return ret;
 }
 
-static inline int get_key_or_die(char *config_file)
+static int get_key_or_die(const char *config_file)
 {
 	int ret;
 	struct stat statbuf;
@@ -257,11 +258,11 @@ static inline int get_key_or_die(char *config_file)
 	return ret;
 }
 
-static int mutex_get(int key, int flags)
+static int mutex_get(key_t key, int flags)
 {
 	int ret;
 
-	DSS_DEBUG_LOG(("getting semaphore 0x%x\n", key));
+	DSS_DEBUG_LOG(("getting semaphore 0x%lx\n", (long)key));
 	ret = semget(key, 2, flags);
 	if (ret < 0)
 		return -ERRNO_TO_DSS_ERROR(errno);
@@ -281,41 +282,33 @@ static int do_semop(int id, struct sembuf *sops, int num)
 	return -ERRNO_TO_DSS_ERROR(errno);
 }
 
-static int mutex_lock(int id)
+static bool mutex_is_locked(int id)
 {
-	struct sembuf sops[4];
+	struct sembuf sops;
 	int ret;
 
-	DSS_DEBUG_LOG(("locking\n"));
-
-	sops[0].sem_num = 0;
-	sops[0].sem_op = 0;
-	sops[0].sem_flg = SEM_UNDO | IPC_NOWAIT;
-
-	sops[1].sem_num = 0;
-	sops[1].sem_op = 1;
-	sops[1].sem_flg = SEM_UNDO | IPC_NOWAIT;
-
-	sops[2].sem_num = 1;
-	sops[2].sem_op = 0;
-	sops[2].sem_flg = SEM_UNDO | IPC_NOWAIT;
+	DSS_DEBUG_LOG(("trying to lock\n"));
 
-	sops[3].sem_num = 1;
-	sops[3].sem_op = 1;
-	sops[3].sem_flg = SEM_UNDO | IPC_NOWAIT;
+	sops.sem_num = 0;
+	sops.sem_op = 0;
+	sops.sem_flg = SEM_UNDO | IPC_NOWAIT;
 
-	ret = do_semop(id, sops, 4);
+	ret = do_semop(id, &sops, 1);
 	if (ret < 0)
-		return -ERRNO_TO_DSS_ERROR(errno);
-	return 1;
+		return true;
+	return false;
 }
 
-static int mutex_try_lock(int id)
+int lock_dss(char *config_file)
 {
-	struct sembuf sops[2];
-	int ret;
+	int ret, id;
+	struct sembuf sops[4];
+	key_t key = get_key_or_die(config_file);
 
-	DSS_DEBUG_LOG(("trying to lock\n"));
+	ret = mutex_get(key, IPC_CREAT | 0600);
+	if (ret < 0)
+		return ret;
+	id = ret;
 
 	sops[0].sem_num = 0;
 	sops[0].sem_op = 0;
@@ -325,36 +318,32 @@ static int mutex_try_lock(int id)
 	sops[1].sem_op = 1;
 	sops[1].sem_flg = SEM_UNDO | IPC_NOWAIT;
 
-	ret = do_semop(id, sops, 2);
-	if (ret < 0)
-		return -ERRNO_TO_DSS_ERROR(errno);
-	return 1;
-}
+	sops[2].sem_num = 1;
+	sops[2].sem_op = 0;
+	sops[2].sem_flg = SEM_UNDO | IPC_NOWAIT;
 
-int lock_dss(char *config_file)
-{
-	int ret, key = get_key_or_die(config_file);
+	sops[3].sem_num = 1;
+	sops[3].sem_op = 1;
+	sops[3].sem_flg = SEM_UNDO | IPC_NOWAIT;
 
-	ret = mutex_get(key, IPC_CREAT | 0600);
-	if (ret < 0)
-		return ret;
-	return mutex_lock(ret);
+	return do_semop(id, sops, 4);
 }
 
 int get_dss_pid(char *config_file, pid_t *pid)
 {
-	int ret, semid, key = get_key_or_die(config_file);
+	int ret, semid;
+	key_t key = get_key_or_die(config_file);
 
+	if (pid)
+		*pid = 0;
 	ret = mutex_get(key, 0);
 	if (ret < 0)
-		return ret;
+		return ret == -ERRNO_TO_DSS_ERROR(ENOENT)? -E_NOT_RUNNING : ret;
 	semid = ret;
 	ret = semctl(semid, 1, GETPID);
 	if (ret < 0)
 		return -E_NOT_RUNNING;
-	*pid = ret;
-	ret = mutex_try_lock(semid);
-	if (ret >= 0)
-		return -E_NOT_RUNNING;
-	return 1;
+	if (pid)
+		*pid = ret;
+	return mutex_is_locked(semid)? 1 : -E_NOT_RUNNING;
 }