X-Git-Url: http://git.tuebingen.mpg.de/?p=paraslash.git;a=blobdiff_plain;f=ipc.c;h=c64cc89c6d8803416a9686890b09592c97a9272e;hp=ae9ad574bbd5840be8cee0c034c8f9e0e48cc7cc;hb=343a65bc48b4e0cda4d9a14afcd7e96cca9c5de9;hpb=c5517c98d28a74a89086b0641e3633d16eaf9df7

diff --git a/ipc.c b/ipc.c
index ae9ad574..c64cc89c 100644
--- a/ipc.c
+++ b/ipc.c
@@ -1,35 +1,70 @@
+/*
+ * Copyright (C) 2006-2009 Andre Noll <maan@systemlinux.org>
+ *
+ * Licensed under the GPL v2. For licencing details see COPYING.
+ */
+
+/** \file ipc.c Inter-process communication and shared memory helpers. */
+
 #include "para.h"
 #include "error.h"
 #include "ipc.h"
 #include <sys/ipc.h>
 #include <sys/shm.h>
+#include <sys/sem.h>
 
-
+/**
+ * Define a new mutex.
+ *
+ * \return The identifier for the new mutex on success, a negative error code
+ * on errors.
+ *
+ * \sa semget(2).
+ */
 int mutex_new(void)
 {
 	int ret = semget(IPC_PRIVATE, 1, IPC_CREAT | 0666);
-	return ret < 0?  -E_SEM_GET : ret;
+	return ret < 0? -ERRNO_TO_PARA_ERROR(errno) : ret;
 }
 
+/**
+ * Destroy a mutex.
+ *
+ * \param id The identifier of the mutex to be destroyed.
+ *
+ * \return Standard.
+ *
+ * \sa semctl(2)
+ */
 int mutex_destroy(int id)
 {
 	int ret = semctl(id, 0, IPC_RMID);
-	return ret < 0? -E_SEM_REMOVE : 1;
+	return ret < 0? -ERRNO_TO_PARA_ERROR(errno) : 1;
 }
 
 static void para_semop(int id, struct sembuf *sops, int num)
 {
-	if (semop(id, sops, num) >= 0)
+	do {
+		if (semop(id, sops, num) >= 0)
+			return;
+	} while (errno == EINTR);
+	if (errno == EIDRM) {
+		PARA_CRIT_LOG("semaphore set %d was removed\n", id);
 		return;
-	PARA_WARNING_LOG("semop failed (%s), retrying\n", strerror(errno));
-	while (semop(id, sops, num) < 0)
-		; /* nothing */
+	}
+	PARA_EMERG_LOG("fatal semop error %s: pid %d\n", strerror(errno),
+		(int)getpid());
+	exit(EXIT_FAILURE);
 }
 
 /**
- * lock the given mutex
+ * Lock the given mutex.
+ *
+ * \param id The identifier of the shared memory area to lock.
+ *
+ * This function either succeeds or aborts.
  *
- * \sa semop(2), struct misc_meta_data
+ * \sa semop(2), struct misc_meta_data.
  */
 void mutex_lock(int id)
 {
@@ -49,9 +84,13 @@ void mutex_lock(int id)
 }
 
 /**
- * unlock a mutex
+ * Unlock a mutex.
  *
- * \sa semop(2), struct misc_meta_data
+ * \param id The identifier of the mutex.
+ *
+ * This function either succeeds or aborts.
+ *
+ * \sa semop(2), struct misc_meta_data.
  */
 void mutex_unlock(int id)
 {
@@ -66,44 +105,69 @@ void mutex_unlock(int id)
 }
 
 /**
- * create a new shared memory area of given size
- * 
- * \sa shmget(2)
+ * Create a new shared memory area of given size.
+ *
+ * \param size The size of the shared memory area to create.
+ *
+ * \return The id of the shared memory array on success, a negative error
+ * code on errors.
+ *
+ * \sa shmget(2).
  */
 int shm_new(size_t size)
 {
 	int ret = shmget(IPC_PRIVATE, size, IPC_CREAT | IPC_EXCL | 0600);
-	return ret < 0 ? -E_SHM_GET : ret;
+	return ret < 0 ? -ERRNO_TO_PARA_ERROR(errno) : ret;
 }
 
 /**
- * destroy the given shared memory area
- * \sa shmctl(2)
- **/
+ * Destroy the given shared memory area.
+ *
+ * \param id The shared memory identifier.
+ *
+ * \return The return value of the underlying shmctl() call on success,
+ * a negative error code on errors.
+ *
+ * \sa shmctl(2).
+ */
 int shm_destroy(int id)
 {
 	struct shmid_ds shm_desc;
 	int ret = shmctl(id, IPC_RMID, &shm_desc);
-	return ret < 0? -E_SHM_DESTROY : ret;
+	return ret < 0? -ERRNO_TO_PARA_ERROR(errno) : ret;
 }
 
 /**
- * attach a shared memory area
+ * Attach a shared memory segment.
  *
- * \sa semop(2)
+ * \param id The identifier of the shared memory segment to attach.
+ * \param mode Either ATTACH_RO (read only) or ATTACH_RW (read/write).
+ * \param result Points to the attached area just attached on success.
+ *
+ * \return Standard.
+ *
+ * \sa shmat(2).
  */
 int shm_attach(int id, enum shm_attach_mode mode, void **result)
 {
-	if (mode == ATTACH_RW) {
+	if (mode == ATTACH_RW)
 		*result = shmat(id, NULL, 0);
-		return *result? 1 : -E_SHM_ATTACH;
-	}
-	*result = shmat(id, NULL, SHM_RDONLY);
-	return *result? 1 : -E_SHM_ATTACH;
+	else
+		*result = shmat(id, NULL, SHM_RDONLY);
+	return *result == (void *) -1? -ERRNO_TO_PARA_ERROR(errno) : 1;
 }
 
+/**
+ * Detach a shared memory segment.
+ *
+ * \param addr The address of the attached segment.
+ *
+ * \return Standard.
+ *
+ * \sa shmdt(2).
+ */
 int shm_detach(void *addr)
 {
 	int ret = shmdt(addr);
-	return ret < 0? -E_SHM_DETACH : 1;
+	return ret < 0? -ERRNO_TO_PARA_ERROR(errno) : 1;
 }