Save also the end of file time value of the afh_info to disk.

[paraslash.git] / ipc.c

diff --git a/ipc.c b/ipc.c
index 973a9eaf4ffee1e69eb5a5e5460f7060f654b433..debf9d11be254ed6cf07d7dc390763cbc0f5fb8d 100644 (file)
--- a/ipc.c
+++ b/ipc.c
@@ -1,17 +1,41 @@
+/*
+ * Copyright (C) 2006-2007 Andre Noll <maan@systemlinux.org>
+ *
+ * Licensed under the GPL v2. For licencing details see COPYING.
+ */
+
+/** \file ipc.c interprocess communication and shared memory helpers */
+

 #include "para.h"
 #include "error.h"
 #include "ipc.h"
 #include <sys/ipc.h>
 #include <sys/shm.h>
 #include "para.h"
 #include "error.h"
 #include "ipc.h"
 #include <sys/ipc.h>
 #include <sys/shm.h>

+#include <sys/sem.h>

 
 

-#define MAX_SEMOP_RETRIES 500
-
+/**
+ * define a new mutex
+ *
+ * \return the identifier for the new mutex on success, \a -E_SEM_GET
+ * 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;
 }
 
 int mutex_new(void)
 {
        int ret = semget(IPC_PRIVATE, 1, IPC_CREAT | 0666);
        return ret < 0?  -E_SEM_GET : ret;
 }
 

+/**
+ * destroy a mutex
+ *
+ * \param id the identifier of the mutex to be destroyed
+ *
+ * \return Positive on success, \a -E_SEM_REMOVE on errors.
+ *
+ * \sa semctl(2)
+ */

 int mutex_destroy(int id)
 {
        int ret = semctl(id, 0, IPC_RMID);
 int mutex_destroy(int id)
 {
        int ret = semctl(id, 0, IPC_RMID);


@@ -20,18 +44,25 @@ int mutex_destroy(int id)
 
 static void para_semop(int id, struct sembuf *sops, int num)
 {
 
 static void para_semop(int id, struct sembuf *sops, int num)
 {

-       int i;
-
-       for (i = 0; i < MAX_SEMOP_RETRIES; i++)
+       do {

                if (semop(id, sops, num) >= 0)
                        return;
                if (semop(id, sops, num) >= 0)
                        return;

-       PARA_EMERG_LOG("semop failed %d times, aborting\n", MAX_SEMOP_RETRIES);
+       } while (errno == EINTR);
+       if (errno == EIDRM) {
+               PARA_NOTICE_LOG("semaphore set %d was removed\n", id);
+               return;
+       }
+       PARA_EMERG_LOG("fatal semop error %s: pid %d\n", strerror(errno), getpid());

        exit(EXIT_FAILURE);
 }
 
 /**
  * lock the given mutex
  *
        exit(EXIT_FAILURE);
 }
 
 /**
  * lock the given mutex
  *

+ * \param id of the shared memory area to lock
+ *
+ * This function either succeeds or aborts.
+ *

  * \sa semop(2), struct misc_meta_data
  */
 void mutex_lock(int id)
  * \sa semop(2), struct misc_meta_data
  */
 void mutex_lock(int id)


@@ -54,6 +85,10 @@ void mutex_lock(int id)
 /**
  * unlock a mutex
  *
 /**
  * unlock a mutex
  *

+ * \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)
  * \sa semop(2), struct misc_meta_data
  */
 void mutex_unlock(int id)


@@ -70,7 +105,11 @@ void mutex_unlock(int id)
 
 /**
  * create a new shared memory area of given size
 
 /**
  * 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 areay on success, \a -E_SHM_GET on errors.
+ *

  * \sa shmget(2)
  */
 int shm_new(size_t size)
  * \sa shmget(2)
  */
 int shm_new(size_t size)


@@ -81,8 +120,14 @@ int shm_new(size_t size)
 
 /**
  * destroy the given shared memory area
 
 /**
  * destroy the given shared memory area

+ *
+ * \param id the shared memory id
+ *
+ * \return The return value of the underlying shmctl() call on success,
+ * \a -E_SHM_DESTROY on errors.
+ *

  * \sa shmctl(2)
  * \sa shmctl(2)

- **/
+ */

 int shm_destroy(int id)
 {
        struct shmid_ds shm_desc;
 int shm_destroy(int id)
 {
        struct shmid_ds shm_desc;


@@ -91,9 +136,15 @@ int shm_destroy(int id)
 }
 
 /**
 }
 
 /**

- * attach a shared memory area
+ * attach a shared memory segment
+ *
+ * \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

  *
  *

- * \sa semop(2)
+ * \return positive on success, \a -E_SHM_ATTACH on errors.
+ *
+ * \sa shmat(2)

  */
 int shm_attach(int id, enum shm_attach_mode mode, void **result)
 {
  */
 int shm_attach(int id, enum shm_attach_mode mode, void **result)
 {


@@ -105,6 +156,15 @@ int shm_attach(int id, enum shm_attach_mode mode, void **result)
        return *result? 1 : -E_SHM_ATTACH;
 }
 
        return *result? 1 : -E_SHM_ATTACH;
 }
 

+/**
+ * detach a shared memory segment
+ *
+ * \param addr the address of the attached segment
+ *
+ * \return positive on success, \a -E_SHM_DETACH on errors.
+ *
+ * \sa shmdt(2)
+ */

 int shm_detach(void *addr)
 {
        int ret = shmdt(addr);
 int shm_detach(void *addr)
 {
        int ret = shmdt(addr);