1 files changed, 258 insertions, 0 deletions
diff --git a/nptl/sem_open.c b/nptl/sem_open.c
new file mode 100644
index 0000000000..6fc72f7dc6
--- /dev/null
+++ b/nptl/sem_open.c
@@ -0,0 +1,258 @@
+/* Copyright (C) 2002 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+   Contributed by Ulrich Drepper <drepper@redhat.com>, 2002.
+
+   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, write to the Free
+   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+   02111-1307 USA.  */
+
+#include <errno.h>
+#include <fcntl.h>
+#include <mntent.h>
+#include <paths.h>
+#include <pthread.h>
+#include <semaphore.h>
+#include <stdarg.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <sys/mman.h>
+#include <sys/stat.h>
+#include <sys/statfs.h>
+#include <linux_fsinfo.h>
+#include "semaphoreP.h"
+
+
+
+/* Information about the mount point.  */
+struct mountpoint_info mountpoint attribute_hidden;
+
+/* This is the default mount point.  */
+static const char defaultmount[] = "/dev/shm";
+/* This is the default directory.  */
+static const char defaultdir[] = "/dev/shm/sem.";
+
+/* Protect the `mountpoint' variable above.  */
+pthread_once_t __namedsem_once attribute_hidden = PTHREAD_ONCE_INIT;
+
+
+/* Determine where the shmfs is mounted (if at all).  */
+void
+attribute_hidden
+__where_is_shmfs (void)
+{
+  char buf[512];
+  struct statfs f;
+  struct mntent resmem;
+  struct mntent *mp;
+  FILE *fp;
+
+  /* The canonical place is /dev/shm.  This is at least what the
+     documentation tells everybody to do.  */
+  if (__statfs (defaultmount, &f) == 0 && f.f_type == SHMFS_SUPER_MAGIC)
+    {
+      /* It is in the normal place.  */
+      mountpoint.dir = (char *) defaultdir;
+      mountpoint.dirlen = sizeof (defaultdir) - 1;
+
+      return;
+    }
+
+  /* OK, do it the hard way.  Look through the /proc/mounts file and if
+     this does not exist through /etc/fstab to find the mount point.  */
+  fp = __setmntent ("/proc/mounts", "r");
+  if (__builtin_expect (fp == NULL, 0))
+    {
+      fp = __setmntent (_PATH_MNTTAB, "r");
+      if (__builtin_expect (fp == NULL, 0))
+	/* There is nothing we can do.  Blind guesses are not helpful.  */
+	return;
+    }
+
+  /* Now read the entries.  */
+  while ((mp = __getmntent_r (fp, &resmem, buf, sizeof buf)) != NULL)
+    /* The original name is "shm" but this got changed in early Linux
+       2.4.x to "tmpfs".  */
+    if (strcmp (mp->mnt_type, "tmpfs") == 0
+	|| strcmp (mp->mnt_type, "shm") == 0)
+      {
+	/* Found it.  There might be more than one place where the
+           filesystem is mounted but one is enough for us.  */
+	size_t namelen;
+
+	/* First make sure this really is the correct entry.  At least
+	   some versions of the kernel give wrong information because
+	   of the implicit mount of the shmfs for SysV IPC.  */
+	if (__statfs (mp->mnt_dir, &f) != 0 || f.f_type != SHMFS_SUPER_MAGIC)
+	  continue;
+
+	namelen = strlen (mp->mnt_dir);
+
+	if (namelen == 0)
+	  /* Hum, maybe some crippled entry.  Keep on searching.  */
+	  continue;
+
+	mountpoint.dir = (char *) malloc (namelen + 4 + 2);
+	if (mountpoint.dir != NULL)
+	  {
+	    char *cp = __mempcpy (mountpoint.dir, mp->mnt_dir, namelen);
+	    if (cp[-1] != '/')
+	      *cp++ = '/';
+	    cp = stpcpy (cp, "sem.");
+	    mountpoint.dirlen = cp - mountpoint.dir;
+	  }
+
+	break;
+      }
+
+  /* Close the stream.  */
+  __endmntent (fp);
+}
+
+
+sem_t *
+sem_open (const char *name, int oflag, ...)
+{
+  char *finalname;
+  size_t namelen;
+  sem_t *result;
+  int fd;
+
+  /* Determine where the shmfs is mounted.  */
+  pthread_once (&__namedsem_once, __where_is_shmfs);
+
+  /* If we don't know the mount points there is nothing we can do.  Ever.  */
+  if (mountpoint.dir == NULL)
+    {
+      __set_errno (ENOSYS);
+      return SEM_FAILED;
+    }
+
+  /* Construct the filename.  */
+  while (name[0] == '/')
+    ++name;
+
+  if (name[0] == '\0')
+    {
+      /* The name "/" is not supported.  */
+      __set_errno (EINVAL);
+      return SEM_FAILED;
+    }
+  namelen = strlen (name);
+
+  /* Create the name of the final file.  */
+  finalname = (char *) alloca (mountpoint.dirlen + namelen + 1);
+  __mempcpy (__mempcpy (finalname, mountpoint.dir, mountpoint.dirlen),
+	     name, namelen + 1);
+
+  /* If the semaphore object has to exist simply open it.  */
+  if ((oflag & O_CREAT) == 0)
+    {
+      fd = open (finalname, oflag | O_NOFOLLOW);
+
+      if (fd == -1)
+	/* Return.  errno is already set.  */
+	return SEM_FAILED;
+
+      /* Map the sem_t structure from the file.  */
+      result = (sem_t *) mmap (NULL, sizeof (sem_t), PROT_READ | PROT_WRITE,
+			       MAP_SHARED, fd, 0);
+    }
+  else
+    {
+      /* We have to open a temporary file first since it must have the
+	 correct form before we can start using it.  */
+      char *tmpfname;
+      mode_t mode;
+      unsigned int value;
+      va_list ap;
+
+      va_start (ap, oflag);
+
+      mode = va_arg (ap, mode_t);
+      value = va_arg (ap, unsigned int);
+
+      va_end (ap);
+
+      if (value > SEM_VALUE_MAX)
+	{
+	  __set_errno (EINVAL);
+	  return SEM_FAILED;
+	}
+
+      tmpfname = (char *) alloca (mountpoint.dirlen + 6 + 1);
+      strcpy (__mempcpy (tmpfname, mountpoint.dir, mountpoint.dirlen),
+	      "XXXXXX");
+
+      fd = mkstemp (tmpfname);
+      if (fd == -1)
+	return SEM_FAILED;
+
+      /* Create the initial file content.  */
+      sem_t initsem;
+
+      struct sem *iinitsem = (struct sem *) &initsem;
+      iinitsem->count = value;
+
+      /* Initialize the remaining bytes as well.  */
+      memset ((char *) &initsem + sizeof (struct sem), '\0',
+	      sizeof (sem_t) - sizeof (struct sem));
+
+      if (TEMP_FAILURE_RETRY (write (fd, &initsem, sizeof (sem_t)))
+	  != sizeof (sem_t)
+	  /* Adjust the permission.  */
+	  || fchmod (fd, mode) != 0)
+	{
+	unlink_return:
+	  unlink (tmpfname);
+	  return SEM_FAILED;
+	}
+
+      /* Map the sem_t structure from the file.  */
+      result = (sem_t *) mmap (NULL, sizeof (sem_t), PROT_READ | PROT_WRITE,
+			       MAP_SHARED, fd, 0);
+      if (result == MAP_FAILED)
+	goto unlink_return;
+
+      /* Create or overwrite the file.  Depending on what is wanted we
+	 use rename or link.  */
+      if ((oflag & O_EXCL) == 0)
+	{
+	  /* An existing file gets overwritten.  */
+	  if (rename (tmpfname, finalname) != 0)
+	    {
+	    unmap_unlink_return:
+	      munmap (result, sizeof (sem_t));
+	      goto unlink_return;
+	    }
+	}
+      else
+	{
+	  /* Don't overwrite an existing file.  */
+	  if (link (tmpfname, finalname) != 0)
+	    goto unmap_unlink_return;
+
+	  /* This went well.  Now remove the temporary name.  This
+	     should never fail.  If it fails we leak a file name.
+	     Better fix the kernel.  */
+	  (void) unlink (tmpfname);
+	}
+    }
+
+  /* We don't need the file descriptor anymore.  */
+  close (fd);
+
+  return result;
+}