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[dss.git] / ipc.c

diff --git a/ipc.c b/ipc.c
index 65ef20049d26748ef54b6fd60068e7492b159beb..183c76e9b4ad0b46ee2910207f12626fbb7087ca 100644 (file)
--- 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;
 }