ipcs: clean up do_shm()

 - don't expect maxid as argument in ipc_shm_get_info()
 - if there is @id argument then use it everywhere in ipc_shm_get_info()
 - don't call shmctl() if not necessary in do_shm()

Signed-off-by: Karel Zak <kzak@redhat.com>

3 files changed, 34 insertions, 14 deletions

diff --git a/sys-utils/ipcs.c b/sys-utils/ipcs.c
index 496fc334c..d0ad42fcd 100644
--- a/sys-utils/ipcs.c
+++ b/sys-utils/ipcs.c
@@ -192,20 +192,14 @@ static void print_perms (int id, struct ipc_perm *ipcp)
 
 static void do_shm (char format)
 {
-	int maxid;
-	struct shm_info shm_info;
 	struct passwd *pw;
-	struct ipc_limits lim;
 	struct shm_data *shmds, *shmdsp;
 
-	maxid = shmctl (0, SHM_INFO, (struct shmid_ds *) (void *) &shm_info);
-	if (maxid < 0) {
-		printf (_("kernel not configured for shared memory\n"));
-		return;
-	}
-
 	switch (format) {
 	case LIMITS:
+	{
+		struct ipc_limits lim;
+
 		printf (_("------ Shared Memory Limits --------\n"));
 		if (ipc_shm_get_limits(&lim))
 			return;
@@ -215,8 +209,18 @@ static void do_shm (char format)
 					(lim.shmall / 1024) * getpagesize());
 		printf (_("min seg size (bytes) = %ju\n"), lim.shmmin);
 		return;
-
+	}
 	case STATUS:
+	{
+		int maxid;
+		struct shm_info shm_info;
+
+		maxid = shmctl (0, SHM_INFO, (struct shmid_ds *) &shm_info);
+		if (maxid < 0) {
+			printf (_("kernel not configured for shared memory\n"));
+			return;
+		}
+
 		printf (_("------ Shared Memory Status --------\n"));
 		/*
 		 * TRANSLATORS: This output format is maintained for backward
@@ -240,7 +244,11 @@ static void do_shm (char format)
 			shm_info.shm_swp,
 			shm_info.swap_attempts, shm_info.swap_successes);
 		return;
+	}
 
+	/*
+	 * Headers only
+	 */
 	case CREATOR:
 		printf (_("------ Shared Memory Segment Creators/Owners --------\n"));
 		printf ("%-10s %-10s %-10s %-10s %-10s %-10s\n",
@@ -268,7 +276,10 @@ static void do_shm (char format)
 		break;
 	}
 
-	if (ipc_shm_get_info(maxid, -1, &shmds) < 1)
+	/*
+	 * Print data
+	 */
+	if (ipc_shm_get_info(-1, &shmds) < 1)
 		return;
 	shmdsp = shmds;
 
diff --git a/sys-utils/ipcutils.c b/sys-utils/ipcutils.c
index c266ad868..959b70c63 100644
--- a/sys-utils/ipcutils.c
+++ b/sys-utils/ipcutils.c
@@ -91,11 +91,12 @@ int ipc_shm_get_limits(struct ipc_limits *lim)
 	return 0;
 }
 
-int ipc_shm_get_info(int maxid, int id, struct shm_data **shmds)
+int ipc_shm_get_info(int id, struct shm_data **shmds)
 {
 	FILE *f;
-	int i;
+	int i, maxid;
 	struct shm_data *p;
+	struct shm_info dummy;
 
 	p = *shmds = xmalloc(sizeof(struct shm_data));
 	p->next = NULL;
@@ -129,6 +130,10 @@ int ipc_shm_get_info(int maxid, int id, struct shm_data **shmds)
 			   &p->shm_swp) != 16)
 			continue;
 
+		if (id > -1 && id != p->shm_perm.id) {
+			i--;
+			continue;	/* id specified, but does not match */
+		}
 		if (id < 0) {
 			p->next = xmalloc(sizeof(struct shm_data));
 			p = p->next;
@@ -145,6 +150,10 @@ int ipc_shm_get_info(int maxid, int id, struct shm_data **shmds)
 fallback:
 	i = id < 0 ? 0 : id;
 
+	maxid = shmctl(0, SHM_INFO, (struct shmid_ds *) &dummy);
+	if (maxid < 0)
+		return 0;
+
 	while (i <= maxid) {
 		int shmid;
 		struct shmid_ds shmseg;
diff --git a/sys-utils/ipcutils.h b/sys-utils/ipcutils.h
index 8e2bfddfb..45a75d84f 100644
--- a/sys-utils/ipcutils.h
+++ b/sys-utils/ipcutils.h
@@ -129,7 +129,7 @@ struct shm_data {
 	struct shm_data  *next;
 };
 
-extern int ipc_shm_get_info(int maxid, int id, struct shm_data **shmds);
+extern int ipc_shm_get_info(int id, struct shm_data **shmds);
 extern void ipc_shm_free_info(struct shm_data *shmds);
 
 #endif /* UTIL_LINUX_IPCUTILS_H */