X-Git-Url: https://git.gag.com/?a=blobdiff_plain;ds=sidebyside;f=lib%2Fopen.c;fp=lib%2Fopen.c;h=8027b473a5a385816248b638a486abce5071aaf5;hb=c7e61475680fa226bd9b8bdd469cd66914e630f5;hp=0000000000000000000000000000000000000000;hpb=800deb09b422a73c1212233a93839a223ff59678;p=debian%2Fgzip

diff --git a/lib/open.c b/lib/open.c
new file mode 100644
index 0000000..8027b47
--- /dev/null
+++ b/lib/open.c
@@ -0,0 +1,166 @@
+/* Open a descriptor to a file.
+   Copyright (C) 2007-2009 Free Software Foundation, Inc.
+
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program 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 General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
+/* Written by Bruno Haible <bruno@clisp.org>, 2007.  */
+
+#include <config.h>
+
+/* Get the original definition of open.  It might be defined as a macro.  */
+#define __need_system_fcntl_h
+#include <fcntl.h>
+#undef __need_system_fcntl_h
+#include <sys/types.h>
+
+static inline int
+orig_open (const char *filename, int flags, mode_t mode)
+{
+  return open (filename, flags, mode);
+}
+
+/* Specification.  */
+#include <fcntl.h>
+
+#include <errno.h>
+#include <stdarg.h>
+#include <string.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <unistd.h>
+
+#ifndef REPLACE_OPEN_DIRECTORY
+# define REPLACE_OPEN_DIRECTORY 0
+#endif
+
+int
+open (const char *filename, int flags, ...)
+{
+  mode_t mode;
+  int fd;
+
+  mode = 0;
+  if (flags & O_CREAT)
+    {
+      va_list arg;
+      va_start (arg, flags);
+
+      /* We have to use PROMOTED_MODE_T instead of mode_t, otherwise GCC 4
+	 creates crashing code when 'mode_t' is smaller than 'int'.  */
+      mode = va_arg (arg, PROMOTED_MODE_T);
+
+      va_end (arg);
+    }
+
+#if (defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__
+  if (strcmp (filename, "/dev/null") == 0)
+    filename = "NUL";
+#endif
+
+#if OPEN_TRAILING_SLASH_BUG
+  /* If the filename ends in a slash and one of O_CREAT, O_WRONLY, O_RDWR
+     is specified, then fail.
+     Rationale: POSIX <http://www.opengroup.org/susv3/basedefs/xbd_chap04.html>
+     says that
+       "A pathname that contains at least one non-slash character and that
+        ends with one or more trailing slashes shall be resolved as if a
+        single dot character ( '.' ) were appended to the pathname."
+     and
+       "The special filename dot shall refer to the directory specified by
+        its predecessor."
+     If the named file already exists as a directory, then
+       - if O_CREAT is specified, open() must fail because of the semantics
+         of O_CREAT,
+       - if O_WRONLY or O_RDWR is specified, open() must fail because POSIX
+         <http://www.opengroup.org/susv3/functions/open.html> says that it
+         fails with errno = EISDIR in this case.
+     If the named file does not exist or does not name a directory, then
+       - if O_CREAT is specified, open() must fail since open() cannot create
+         directories,
+       - if O_WRONLY or O_RDWR is specified, open() must fail because the
+         file does not contain a '.' directory.  */
+  if (flags & (O_CREAT | O_WRONLY | O_RDWR))
+    {
+      size_t len = strlen (filename);
+      if (len > 0 && filename[len - 1] == '/')
+	{
+	  errno = EISDIR;
+	  return -1;
+	}
+    }
+#endif
+
+  fd = orig_open (filename, flags, mode);
+
+#if REPLACE_FCHDIR
+  /* Implementing fchdir and fdopendir requires the ability to open a
+     directory file descriptor.  If open doesn't support that (as on
+     mingw), we use a dummy file that behaves the same as directories
+     on Linux (ie. always reports EOF on attempts to read()), and
+     override fstat() in fchdir.c to hide the fact that we have a
+     dummy.  */
+  if (REPLACE_OPEN_DIRECTORY && fd < 0 && errno == EACCES
+      && (flags & O_ACCMODE) == O_RDONLY)
+    {
+      struct stat statbuf;
+      if (stat (filename, &statbuf) == 0 && S_ISDIR (statbuf.st_mode))
+        {
+          /* Maximum recursion depth of 1.  */
+          fd = open ("/dev/null", flags, mode);
+          if (0 <= fd)
+            fd = _gl_register_fd (fd, filename);
+        }
+      else
+        errno = EACCES;
+    }
+#endif
+
+#if OPEN_TRAILING_SLASH_BUG
+  /* If the filename ends in a slash and fd does not refer to a directory,
+     then fail.
+     Rationale: POSIX <http://www.opengroup.org/susv3/basedefs/xbd_chap04.html>
+     says that
+       "A pathname that contains at least one non-slash character and that
+        ends with one or more trailing slashes shall be resolved as if a
+        single dot character ( '.' ) were appended to the pathname."
+     and
+       "The special filename dot shall refer to the directory specified by
+        its predecessor."
+     If the named file without the slash is not a directory, open() must fail
+     with ENOTDIR.  */
+  if (fd >= 0)
+    {
+      /* We know len is positive, since open did not fail with ENOENT.  */
+      size_t len = strlen (filename);
+      if (filename[len - 1] == '/')
+	{
+	  struct stat statbuf;
+
+	  if (fstat (fd, &statbuf) >= 0 && !S_ISDIR (statbuf.st_mode))
+	    {
+	      close (fd);
+	      errno = ENOTDIR;
+	      return -1;
+	    }
+	}
+    }
+#endif
+
+#if REPLACE_FCHDIR
+  if (!REPLACE_OPEN_DIRECTORY && 0 <= fd)
+    fd = _gl_register_fd (fd, filename);
+#endif
+
+  return fd;
+}