ipcs: determine ipc limits from /proc

Some of the limit values are not dynamic.  Like in kernel these values
are #defined.

[kzak@redhat.com: - use better names for functions,
                  - add ipcutils.{c,h}
                  - read also shmmax from /proc]

Signed-off-by: Sami Kerola <kerolasa@iki.fi>
Signed-off-by: Karel Zak <kzak@redhat.com>

1 files changed, 102 insertions, 0 deletions

diff --git a/sys-utils/ipcutils.h b/sys-utils/ipcutils.h
new file mode 100644
index 000000000..ef539ee6c
--- /dev/null
+++ b/sys-utils/ipcutils.h
@@ -0,0 +1,102 @@
+#ifndef UTIL_LINUX_IPCUTILS_H
+#define UTIL_LINUX_IPCUTILS_H
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/ipc.h>
+#include <sys/msg.h>
+#include <sys/sem.h>
+#include <sys/shm.h>
+#include <sys/types.h>
+#include <time.h>
+#include <unistd.h>
+#include <grp.h>
+#include <pwd.h>
+
+/*
+ * SHM_DEST and SHM_LOCKED are defined in kernel headers, but inside
+ * #ifdef __KERNEL__ ... #endif
+ */
+#ifndef SHM_DEST
+  /* shm_mode upper byte flags */
+# define SHM_DEST	01000	/* segment will be destroyed on last detach */
+# define SHM_LOCKED	02000	/* segment will not be swapped */
+#endif
+
+/* For older kernels the same holds for the defines below */
+#ifndef MSG_STAT
+# define MSG_STAT	11
+# define MSG_INFO	12
+#endif
+
+#ifndef SHM_STAT
+# define SHM_STAT	13
+# define SHM_INFO	14
+struct shm_info {
+	int used_ids;
+	ulong shm_tot;		/* total allocated shm */
+	ulong shm_rss;		/* total resident shm */
+	ulong shm_swp;		/* total swapped shm */
+	ulong swap_attempts;
+	ulong swap_successes;
+};
+#endif
+
+#ifndef SEM_STAT
+# define SEM_STAT	18
+# define SEM_INFO	19
+#endif
+
+/* Some versions of libc only define IPC_INFO when __USE_GNU is defined. */
+#ifndef IPC_INFO
+# define IPC_INFO	3
+#endif
+
+/*
+ *  * The last arg of semctl is a union semun, but where is it defined? X/OPEN
+ *   * tells us to define it ourselves, but until recently Linux include files
+ *    * would also define it.
+ *     */
+#ifndef HAVE_UNION_SEMUN
+/* according to X/OPEN we have to define it ourselves */
+union semun {
+	int val;
+	struct semid_ds *buf;
+	unsigned short int *array;
+	struct seminfo *__buf;
+};
+#endif
+
+/*
+ * X/OPEN (Jan 1987) does not define fields key, seq in struct ipc_perm;
+ *	glibc-1.09 has no support for sysv ipc.
+ *	glibc 2 uses __key, __seq
+ */
+#if defined (__GLIBC__) && __GLIBC__ >= 2
+# define KEY __key
+#else
+# define KEY key
+#endif
+
+struct ipc_limits {
+	uint64_t	shmmni;		/* max number of segments */
+	uint64_t	shmmax;		/* max segment size */
+	uint64_t	shmall;		/* max total shared memory */
+	uint64_t	shmmin;		/* min segment size */
+
+	int		semmni;		/* max number of arrays */
+	int		semmsl;		/* max semaphores per array */
+	int		semmns;		/* max semaphores system wide */
+	int		semopm;		/* max ops per semop call */
+	unsigned int	semvmx;		/* semaphore max value (constant) */
+
+	int		msgmni;		/* max queues system wide */
+	size_t		msgmax;		/* max size of message */
+	int		msgmnb;		/* default max size of queue */
+};
+
+extern int ipc_msg_get_limits(struct ipc_limits *lim);
+extern int ipc_sem_get_limits(struct ipc_limits *lim);
+extern int ipc_shm_get_limits(struct ipc_limits *lim);
+
+#endif /* UTIL_LINUX_IPCUTILS_H */