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, 89 insertions, 0 deletions

diff --git a/sys-utils/ipcutils.c b/sys-utils/ipcutils.c
new file mode 100644
index 000000000..041f35062
--- /dev/null
+++ b/sys-utils/ipcutils.c
@@ -0,0 +1,89 @@
+
+#include "c.h"
+#include "path.h"
+#include "pathnames.h"
+#include "ipcutils.h"
+
+#ifndef SEMVMX
+# define SEMVMX  32767	/* <= 32767 semaphore maximum value */
+#endif
+#ifndef SHMMIN
+# define SHMMIN 1	/* min shared segment size in bytes */
+#endif
+
+
+int ipc_msg_get_limits(struct ipc_limits *lim)
+{
+	if (path_exist(_PATH_PROC_IPC_MSGMNI) &&
+	    path_exist(_PATH_PROC_IPC_MSGMNB) &&
+	    path_exist(_PATH_PROC_IPC_MSGMAX)) {
+
+		lim->msgmni = path_read_s32(_PATH_PROC_IPC_MSGMNI);
+		lim->msgmnb = path_read_s32(_PATH_PROC_IPC_MSGMNB);
+		lim->msgmax = path_read_s32(_PATH_PROC_IPC_MSGMAX);
+	} else {
+		struct msginfo msginfo;
+
+		if (msgctl(0, IPC_INFO, (struct msqid_ds *) &msginfo) < 0)
+			return 1;
+		lim->msgmni = msginfo.msgmni;
+		lim->msgmnb = msginfo.msgmnb;
+		lim->msgmax = msginfo.msgmax;
+	}
+
+	return 0;
+}
+
+int ipc_sem_get_limits(struct ipc_limits *lim)
+{
+	FILE *f;
+	int rc = 0;
+
+	lim->semvmx = SEMVMX;
+
+	f = path_fopen("r", 0, _PATH_PROC_IPC_SEM);
+	if (f) {
+		rc = fscanf(f, "%d\t%d\t%d\t%d",
+		       &lim->semmsl, &lim->semmns, &lim->semopm, &lim->semmni);
+		fclose(f);
+
+	}
+
+	if (rc == 4) {
+		struct seminfo seminfo;
+		union semun arg = { .array = (ushort *) &seminfo };
+
+		if (semctl(0, 0, IPC_INFO, arg) < 0)
+			return 1;
+		lim->semmni = seminfo.semmni;
+		lim->semmsl = seminfo.semmsl;
+		lim->semmns = seminfo.semmns;
+		lim->semopm = seminfo.semopm;
+	}
+
+	return 0;
+}
+
+int ipc_shm_get_limits(struct ipc_limits *lim)
+{
+	lim->shmmin = SHMMIN;
+
+	if (path_exist(_PATH_PROC_IPC_SHMALL) &&
+	    path_exist(_PATH_PROC_IPC_SHMMAX) &&
+	    path_exist(_PATH_PROC_IPC_SHMMNI)) {
+
+		lim->shmall = path_read_u64(_PATH_PROC_IPC_SHMALL);
+		lim->shmmax = path_read_u64(_PATH_PROC_IPC_SHMMAX);
+		lim->shmmni = path_read_u64(_PATH_PROC_IPC_SHMMNI);
+
+	} else {
+		struct shminfo shminfo;
+
+		if (shmctl(0, IPC_INFO, (struct shmid_ds *) &shminfo) < 0)
+			return 1;
+		lim->shmmni = shminfo.shmmni;
+		lim->shmall = shminfo.shmall;
+	}
+
+	return 0;
+}