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-rw-r--r--sysdeps/mach/hurd/shmget.c242
1 files changed, 242 insertions, 0 deletions
diff --git a/sysdeps/mach/hurd/shmget.c b/sysdeps/mach/hurd/shmget.c
new file mode 100644
index 0000000000..2065b41989
--- /dev/null
+++ b/sysdeps/mach/hurd/shmget.c
@@ -0,0 +1,242 @@
+/* SysV shmget for Hurd.
+ Copyright (C) 2005-2015 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ The GNU C Library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library; if not, see
+ <http://www.gnu.org/licenses/>. */
+
+#include <stdbool.h>
+#include <stdlib.h>
+#include <errno.h>
+#include <sys/shm.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <limits.h>
+#include <stdio.h>
+#include <fcntl.h>
+#include <unistd.h>
+
+#include <hurd/fd.h>
+
+#include "sysvshm.h"
+
+/* Create a new shared memory segment file without linking it into the
+ filesystem. Return the directory and file ports in R_DIR and R_FILE. */
+static error_t
+create_shm_file (size_t size, int flags, file_t *r_dir, file_t *r_file)
+{
+ error_t err;
+ file_t dir;
+ file_t file;
+
+ flags &= 0777;
+
+ /* Get a port to the directory that will contain the file. */
+ dir = __file_name_lookup (SHM_DIR, 0, 0);
+ if (dir == MACH_PORT_NULL)
+ return errno;
+
+ /* Create an unnamed file in the directory. */
+ err = __dir_mkfile (dir, O_RDWR, flags, &file);
+ if (err)
+ {
+ __mach_port_deallocate (__mach_task_self (), dir);
+ return err;
+ }
+
+ err = __file_set_size (file, size);
+ if (err)
+ {
+ __mach_port_deallocate (__mach_task_self (), file);
+ __mach_port_deallocate (__mach_task_self (), dir);
+
+ return err;
+ }
+
+ *r_dir = dir;
+ *r_file = file;
+
+ return 0;
+}
+
+
+/* Open the shared memory segment *R_KEY and return a file descriptor
+ to it in R_FD. If KEY is IPC_PRIVATE, use a private key and return
+ it in R_KEY. */
+static error_t
+get_exclusive (int shmflags, size_t size, key_t *r_key, int *r_fd)
+{
+ error_t err;
+ file_t dir;
+ file_t file;
+ char filename[SHM_NAMEMAX];
+ key_t key = *r_key;
+ bool is_private;
+
+ /* Create the shared memory segment. */
+ err = create_shm_file (size, shmflags, &dir, &file);
+ if (err)
+ return err;
+
+ if (key == IPC_PRIVATE)
+ {
+ is_private = true;
+ key = SHM_PRIV_KEY_START;
+
+ /* Try to link the shared memory segment into the filesystem
+ (exclusively). */
+ do
+ {
+ sprintf (filename, SHM_NAMEPRI, key);
+ err = __dir_link (dir, file, filename, 1);
+ if (!err)
+ {
+ /* We are done. */
+ *r_key = key;
+ break;
+ }
+ else if (err == EEXIST)
+ {
+ /* Check if we ran out of keys. If not, try again with new
+ key. */
+ if (key == SHM_PRIV_KEY_END)
+ err = ENOSPC;
+ else
+ err = 0;
+
+ key--;
+ }
+ }
+ while (!err);
+ }
+ else
+ {
+ /* Try to link the shared memory segment into the filesystem
+ (exclusively) under the given key. */
+ sprintf (filename, SHM_NAMEPRI, key);
+ err = __dir_link (dir, file, filename, 1);
+ }
+
+ __mach_port_deallocate (__mach_task_self (), dir);
+
+ if (!err)
+ {
+ int fd;
+
+ /* Get a file descriptor for that port. */
+ fd = _hurd_intern_fd (file, O_RDWR, 1); /* dealloc on error */
+ if (fd < 0)
+ err = errno;
+ else
+ *r_fd = fd;
+ }
+
+ return err;
+}
+
+
+/* Open the shared memory segment KEY (creating it if it doesn't yet
+ exist) and return a file descriptor to it in R_FD. */
+static error_t
+get_shared (int shmflags, size_t size, key_t key, int *r_fd)
+{
+ error_t err = 0;
+ char filename[sizeof (SHM_DIR) - 1 + SHM_NAMEMAX];
+ int fd = -1;
+ sprintf (filename, SHM_DIR SHM_NAMEPRI, key);
+
+ do
+ {
+ fd = __open (filename, O_NORW, shmflags & 0777);
+
+ if (fd < 0 && errno != ENOENT)
+ /* We give up. */
+ return errno;
+ else if (fd >= 0)
+ {
+ int res;
+ struct stat statbuf;
+
+ /* Check the size (we only need to do this if we did not
+ create the shared memory segment file ourselves). */
+ res = __fstat (fd, &statbuf);
+ if (res < 0)
+ {
+ err = errno;
+ __close (fd);
+ return err;
+ }
+
+ if (statbuf.st_size < size)
+ {
+ __close (fd);
+ return EINVAL;
+ }
+ }
+ else
+ {
+ /* The memory segment doesn't exist. */
+ if (shmflags & IPC_CREAT)
+ {
+ /* Try to create it exclusively. */
+ err = get_exclusive (shmflags, size, &key, &fd);
+ if (err == EEXIST)
+ /* If somebody created it in the meanwhile, just try again. */
+ err = 0;
+ }
+ else
+ err = ENOENT;
+ }
+ }
+ while (fd < 0 && !err);
+
+ if (!err)
+ *r_fd = fd;
+ else
+ *r_fd = -1;
+
+ return err;
+}
+
+/* Return an identifier for an shared memory segment of at least size
+ SIZE which is associated with KEY. */
+int
+__shmget (key_t key, size_t size, int shmflags)
+{
+ error_t err;
+ int fd;
+
+ if (key == IPC_PRIVATE || shmflags & IPC_EXCL)
+ /* An exclusive shared memory segment must be created. */
+ err = get_exclusive (shmflags, size, &key, &fd);
+ else
+ err = get_shared (shmflags, size, key, &fd);
+
+ if (err)
+ {
+ errno = err;
+ return -1;
+ }
+
+ /* From here, we can't fail. That's important, as otherwise we
+ would need to unlink the file if we created it (in that case, the
+ code above would have to be changed to pass a "created" flag down
+ to the caller). */
+
+ __close (fd);
+
+ return key;
+}
+
+weak_alias(__shmget, shmget)