vss: Add documentation of MAP_POPULATE.

[paraslash.git] / ipc.c

diff --git a/ipc.c b/ipc.c
index 40f6a9512287e2689c140f0e5d31017dff5cea83..85013a636cb3a7f634d190d9044808454274efd8 100644 (file)
--- a/ipc.c
+++ b/ipc.c
@@ -1,8 +1,4 @@
-/*
- * Copyright (C) 2006-2013 Andre Noll <maan@systemlinux.org>
- *
- * Licensed under the GPL v2. For licencing details see COPYING.
- */
+/* Copyright (C) 2006 Andre Noll <maan@tuebingen.mpg.de>, see file COPYING. */
 
 /** \file ipc.c Inter-process communication and shared memory helpers. */
 
@@ -68,7 +64,7 @@ static void para_semop(int id, struct sembuf *sops, int num)
  *
  * This function either succeeds or aborts.
  *
- * \sa semop(2), struct misc_meta_data.
+ * \sa semop(2), struct \ref misc_meta_data.
  */
 void mutex_lock(int id)
 {
@@ -94,7 +90,7 @@ void mutex_lock(int id)
  *
  * This function either succeeds or aborts.
  *
- * \sa semop(2), struct misc_meta_data.
+ * \sa semop(2), struct \ref misc_meta_data.
  */
 void mutex_unlock(int id)
 {
@@ -161,6 +157,27 @@ int shm_attach(int id, enum shm_attach_mode mode, void **result)
        return *result == (void *) -1? -ERRNO_TO_PARA_ERROR(errno) : 1;
 }
 
+/**
+ * Get the size of a shared memory segment.
+ *
+ * \param id The shared memory segment identifier.
+ * \param result Size in bytes is returned here, zero on errors.
+ *
+ * \return Standard.
+ *
+ * \sa shmctl(2).
+ */
+int shm_size(int id, size_t *result)
+{
+       struct shmid_ds ds; /* data structure */
+
+       *result = 0;
+       if (shmctl(id, IPC_STAT, &ds) < 0)
+               return -ERRNO_TO_PARA_ERROR(errno);
+       *result = ds.shm_segsz;
+       return 1;
+}
+
 /**
  * Detach a shared memory segment.
  *
@@ -209,6 +226,7 @@ size_t shm_get_shmmax(void)
                                buf[ret] = '\0';
                                shmmax = strtoul(buf, NULL, 10);
                        }
+                       close(fd);
                }
        }
 #elif defined SYSCTL_SHMMAX_VARIABLE
@@ -221,7 +239,7 @@ size_t shm_get_shmmax(void)
 #endif
        if (shmmax == 0) {
                PARA_WARNING_LOG("unable to determine shmmax\n");
-               shmmax = 65535; /* last ressort */
+               shmmax = 65535; /* last resort */
        }
        PARA_INFO_LOG("shmmax: %zu\n", shmmax);
        return shmmax;