add stub for shm_open() and shm_unlink

  Untested and needs testsuite exercise added

Signed-off-by: Bernhard Reutner-Fischer <rep.dot.nop@gmail.com>

diff --git a/librt/shm.c b/librt/shm.c
new file mode 100644 (file)
index 0000000..637e945
--- /dev/null
+++ b/librt/shm.c
@@ -0,0 +1,98 @@
+/* Copyright (C) 2009 Bernhard Reutner-Fischer <uclibc@uclibc.org>
+ *
+ * Licensed under the LGPL v2.1, see the file COPYING.LIB in this tarball.
+ */
+
+#include <features.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <stdio.h>
+
+#ifndef O_CLOEXEC
+#include <errno.h>
+#endif
+
+#ifndef _PATH_SHM
+#define _PATH_SHM "/dev/shm/"
+#endif
+
+#ifndef NAME_MAX
+#define NAME_MAX 255
+#endif
+
+/* Get name of dummy shm operation handle.
+ * Returns a malloc'ed buffer containing the OS specific path
+ * to the shm filename or NULL upon failure.
+ */
+static __attribute_noinline__ char* get_shm_name(const char*name) __nonnull((1));
+static char* get_shm_name(const char*name)
+{
+       char *path;
+       int i;
+
+       /* Skip leading slashes */
+       while (*name == '/')
+               ++name;
+#ifdef __USE_GNU
+       i = asprintf(&path, _PATH_SHM "%s", name);
+       if (i < 0)
+               return NULL;
+#else
+       path = malloc(NAME_MAX);
+       if (path == NULL)
+               return NULL;
+       i = snprintf(path, NAME_MAX, _PATH_SHM "%s", name);
+       if (i < 0) {
+               free(path);
+               return NULL;
+       }
+#endif
+       return path;
+}
+
+int shm_open(const char *name, int oflag, mode_t mode)
+{
+       int fd, old_errno;
+       char *shm_name = get_shm_name(name);
+
+       /* Stripped multiple '/' from start; may have set errno properly */
+       if (shm_name == NULL)
+               return -1;
+       /* The FD_CLOEXEC file descriptor flag associated with the new
+        * file descriptor is set.  */
+#ifdef O_CLOEXEC
+        /* Just open it with CLOEXEC set, for brevity */
+       fd = open(shm_name, oflag | O_CLOEXEC, mode);
+#else
+       fd = open(shm_name, oflag, mode);
+       if (fd >= 0) {
+               int fdflags = fcntl(fd, F_GETFD, 0);
+               if (fdflags >= 0)
+                       fdflags = fcntl(fd, F_SETFD, fdflags | FD_CLOEXEC);
+               if (fdflags < 0) {
+                       close(fd);
+                       fd = -1;
+               }
+       }
+#endif
+       old_errno = errno;
+       free(shm_name);
+       errno = old_errno;
+       return fd;
+}
+
+int shm_unlink(const char *name)
+{
+       char *shm_name = get_shm_name(name);
+       int ret;
+
+       /* Stripped multiple '/' from start; may have set errno properly */
+       if (shm_name == NULL)
+               return -1;
+       ret = unlink(shm_name);
+       free(shm_name);
+       return ret;
+}