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changeset 12267:c400da5f66bb

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mknod: new module Solaris 9 mknod("name/",mode,dev) mistakenly creates "name" for non-directory mode. FreeBSD 7.2 mknod("dangling/",mode,dev) mistakenly creates the target of the symlink if run as root. FreeBSD and OpenBSD mknod("fifo",S_IFIFO|mode,0) fails for non-root. Use of mknod caused link failures on mingw. * modules/mknod: New file. * m4/mknod.m4 (gl_FUNC_MKNOD): Likewise. * lib/mknod.c (mknod): Likewise. * m4/sys_stat_h.m4 (gl_SYS_STAT_H_DEFAULTS): Set witness defaults. * modules/sys_stat (Makefile.am): Substitute them. * lib/sys_stat.in.h (mknod): Declare replacement. * MODULES.html.sh (Support for systems lacking POSIX:2008): Document it. * doc/posix-functions/mknod.texi (mknod): Likewise. * modules/mknod-tests: New test. * tests/test-mknod.c: Likewise. Signed-off-by: Eric Blake <ebb9@byu.net>
author Eric Blake <ebb9@byu.net>
date Wed, 11 Nov 2009 13:23:04 -0700
parents 37fd04a02bc8
children b537cb58d506
files ChangeLog MODULES.html.sh doc/posix-functions/mknod.texi lib/mknod.c lib/sys_stat.in.h m4/mknod.m4 m4/sys_stat_h.m4 modules/mknod modules/mknod-tests modules/sys_stat tests/test-mknod.c
diffstat 11 files changed, 273 insertions(+), 4 deletions(-) [+]
line wrap: on
line diff
--- a/ChangeLog	Wed Nov 11 13:22:04 2009 -0700
+++ b/ChangeLog	Wed Nov 11 13:23:04 2009 -0700
@@ -1,5 +1,19 @@
 2009-11-11  Eric Blake  <ebb9@byu.net>
 
+	mknod: new module
+	* modules/mknod: New file.
+	* m4/mknod.m4 (gl_FUNC_MKNOD): Likewise.
+	* lib/mknod.c (mknod): Likewise.
+	* m4/sys_stat_h.m4 (gl_SYS_STAT_H_DEFAULTS): Set witness
+	defaults.
+	* modules/sys_stat (Makefile.am): Substitute them.
+	* lib/sys_stat.in.h (mknod): Declare replacement.
+	* MODULES.html.sh (Support for systems lacking POSIX:2008):
+	Document it.
+	* doc/posix-functions/mknod.texi (mknod): Likewise.
+	* modules/mknod-tests: New test.
+	* tests/test-mknod.c: Likewise.
+
 	mkfifo: new module
 	* modules/mkfifo: New file.
 	* m4/mkfifo.m4 (gl_FUNC_MKFIFO): Likewise.
--- a/MODULES.html.sh	Wed Nov 11 13:22:04 2009 -0700
+++ b/MODULES.html.sh	Wed Nov 11 13:23:04 2009 -0700
@@ -2288,6 +2288,7 @@
   func_module mkdir
   func_module mkdtemp
   func_module mkfifo
+  func_module mknod
   func_module mkstemp
   func_module netdb
   func_module netinet_in
--- a/doc/posix-functions/mknod.texi	Wed Nov 11 13:22:04 2009 -0700
+++ b/doc/posix-functions/mknod.texi	Wed Nov 11 13:23:04 2009 -0700
@@ -4,15 +4,26 @@
 
 POSIX specification: @url{http://www.opengroup.org/onlinepubs/9699919799/functions/mknod.html}
 
-Gnulib module: ---
+Gnulib module: mknod
 
 Portability problems fixed by Gnulib:
 @itemize
+@item
+This function requires super-user privileges to create a fifo:
+FreeBSD 7.2, OpenBSD 3.8.
+@item
+This function mishandles trailing slash on some platforms:
+FreeBSD 7.2, Solaris 9.
+@item
+This function is missing on some platforms; however, the replacement
+always fails with @code{ENOSYS}:
+mingw.
 @end itemize
 
 Portability problems not fixed by Gnulib:
 @itemize
 @item
-This function is missing on some platforms:
-mingw.
+Use of this function for anything except fifos is not portable,
+generally requiring super-user privileges and knowledge of supported
+device numbers.
 @end itemize
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/lib/mknod.c	Wed Nov 11 13:23:04 2009 -0700
@@ -0,0 +1,74 @@
+/* Create a device inode.
+   Copyright (C) 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 Eric Blake */
+
+#include <config.h>
+
+#include <sys/stat.h>
+
+#include <errno.h>
+#include <string.h>
+
+#if !HAVE_MKNOD
+/* Mingw lacks mknod; always fail with ENOSYS.  */
+
+int
+mknod (char const *name _UNUSED_PARAMETER_, mode_t mode _UNUSED_PARAMETER_,
+       dev_t dev _UNUSED_PARAMETER_)
+{
+  errno = ENOSYS;
+  return -1;
+}
+
+#else /* HAVE_MKNOD */
+
+# undef mknod
+
+/* Create a file system node FILE, with access permissions and file
+   type in MODE, and device type in DEV.  Usually, non-root
+   applications can only create named fifos (mode includes S_IFIFO),
+   with DEV set to 0.  Also work around trailing slash bugs.  */
+
+int
+rpl_mknod (char const *name, mode_t mode, dev_t dev)
+{
+# if MKFIFO_TRAILING_SLASH_BUG
+  /* Trailing slash only makes sense for directories.  Of course,
+     using mknod to create a directory is not very portable, so it may
+     still fail later on.  */
+  if (!S_ISDIR (mode))
+    {
+      size_t len = strlen (name);
+      if (len && name[len - 1] == '/')
+        {
+          struct stat st;
+          if (stat (name, &st) == 0)
+            errno = EEXIST;
+          return -1;
+        }
+    }
+# endif
+# if MKNOD_FIFO_BUG
+  /* POSIX requires mknod to create fifos for non-privileged
+     processes, but BSD implementations fail with EPERM.  */
+  if (S_ISFIFO (mode) && dev == 0)
+    return mkfifo (name, mode & ~S_IFIFO);
+# endif
+  return mknod (name, mode, dev);
+}
+
+#endif /* HAVE_MKNOD */
--- a/lib/sys_stat.in.h	Wed Nov 11 13:22:04 2009 -0700
+++ b/lib/sys_stat.in.h	Wed Nov 11 13:23:04 2009 -0700
@@ -454,6 +454,23 @@
 #endif
 
 
+#if @GNULIB_MKNOD@
+# if @REPLACE_MKNOD@
+#  undef mknod
+#  define mknod rpl_mknod
+# endif
+# if !@HAVE_MKNOD@ || @REPLACE_MKNOD@
+int mknod (char const *file, mode_t mode, dev_t dev);
+# endif
+#elif defined GNULIB_POSIXCHECK
+# undef mknod
+# define mknod(n,m,d)                                                   \
+    (GL_LINK_WARNING ("mknod is not portable - "                        \
+                      "use gnulib module mknod for portability"),       \
+     mknod (n, m, d))
+#endif
+
+
 #if @GNULIB_MKNODAT@
 # if !@HAVE_MKNODAT@
 int mknodat (int fd, char const *file, mode_t mode, dev_t dev);
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/m4/mknod.m4	Wed Nov 11 13:23:04 2009 -0700
@@ -0,0 +1,45 @@
+# serial 1
+# See if we need to provide mknod replacement.
+
+dnl Copyright (C) 2009 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+# Written by Eric Blake.
+
+AC_DEFUN([gl_FUNC_MKNOD],
+[
+  AC_REQUIRE([gl_SYS_STAT_H_DEFAULTS])
+  AC_REQUIRE([gl_FUNC_MKFIFO])
+  AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
+  AC_CHECK_FUNCS_ONCE([mknod])
+  if test $ac_cv_func_mknod = no; then
+    HAVE_MKNOD=0
+    AC_LIBOBJ([mknod])
+  else
+    dnl Detect BSD bug, where mknod requires root privileges to create fifo.
+    AC_CACHE_CHECK([whether mknod can create fifo without root privileges],
+      [gl_cv_func_mknod_works],
+      [AC_RUN_IFELSE(
+         [AC_LANG_PROGRAM(
+           [[#include <sys/stat.h>
+             #include <unistd.h>
+]], [[/* Indeterminate for super-user, assume no.  Why are you running
+         configure as root, anyway?  */
+      if (!geteuid ()) return 1;
+      if (mknod ("conftest.fifo", S_IFIFO | 0600, 0)) return 2;]])],
+         [gl_cv_func_mknod_works=yes], [gl_cv_func_mknod_works=no],
+         [gl_cv_func_mknod_works="guessing no"])
+       rm -f conftest.fifo])
+    if test "$gl_cv_func_mknod_works" != yes; then
+      AC_DEFINE([MKNOD_FIFO_BUG], [1], [Define to 1 if mknod cannot create
+        a fifo without super-user privileges])
+    fi
+    dnl Systems that mishandle trailing slash on mkfifo also goof on mknod.
+    if test $REPLACE_MKFIFO = 1 || test "$gl_cv_func_mknod_works" != yes; then
+      REPLACE_MKNOD=1
+      AC_LIBOBJ([mknod])
+    fi
+  fi
+])
--- a/m4/sys_stat_h.m4	Wed Nov 11 13:22:04 2009 -0700
+++ b/m4/sys_stat_h.m4	Wed Nov 11 13:23:04 2009 -0700
@@ -1,4 +1,4 @@
-# sys_stat_h.m4 serial 20   -*- Autoconf -*-
+# sys_stat_h.m4 serial 21   -*- Autoconf -*-
 dnl Copyright (C) 2006-2009 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -47,6 +47,7 @@
   GNULIB_MKDIRAT=0;     AC_SUBST([GNULIB_MKDIRAT])
   GNULIB_MKFIFO=0;      AC_SUBST([GNULIB_MKFIFO])
   GNULIB_MKFIFOAT=0;    AC_SUBST([GNULIB_MKFIFOAT])
+  GNULIB_MKNOD=0;       AC_SUBST([GNULIB_MKNOD])
   GNULIB_MKNODAT=0;     AC_SUBST([GNULIB_MKNODAT])
   GNULIB_STAT=0;        AC_SUBST([GNULIB_STAT])
   GNULIB_UTIMENSAT=0;   AC_SUBST([GNULIB_UTIMENSAT])
@@ -59,6 +60,7 @@
   HAVE_MKDIRAT=1;       AC_SUBST([HAVE_MKDIRAT])
   HAVE_MKFIFO=1;        AC_SUBST([HAVE_MKFIFO])
   HAVE_MKFIFOAT=1;      AC_SUBST([HAVE_MKFIFOAT])
+  HAVE_MKNOD=1;         AC_SUBST([HAVE_MKNOD])
   HAVE_MKNODAT=1;       AC_SUBST([HAVE_MKNODAT])
   HAVE_UTIMENSAT=1;     AC_SUBST([HAVE_UTIMENSAT])
   REPLACE_FSTAT=0;      AC_SUBST([REPLACE_FSTAT])
@@ -67,6 +69,7 @@
   REPLACE_LSTAT=0;      AC_SUBST([REPLACE_LSTAT])
   REPLACE_MKDIR=0;      AC_SUBST([REPLACE_MKDIR])
   REPLACE_MKFIFO=0;     AC_SUBST([REPLACE_MKFIFO])
+  REPLACE_MKNOD=0;      AC_SUBST([REPLACE_MKNOD])
   REPLACE_STAT=0;       AC_SUBST([REPLACE_STAT])
   REPLACE_UTIMENSAT=0;  AC_SUBST([REPLACE_UTIMENSAT])
 ])
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/modules/mknod	Wed Nov 11 13:23:04 2009 -0700
@@ -0,0 +1,26 @@
+Description:
+mknod(): create various special devices
+
+Files:
+lib/mknod.c
+m4/mknod.m4
+
+Depends-on:
+mkfifo
+stat
+sys_stat
+
+configure.ac:
+gl_FUNC_MKNOD
+gl_UNISTD_MODULE_INDICATOR([mknod])
+
+Makefile.am:
+
+Include:
+<sys/stat.h>
+
+License:
+LGPL
+
+Maintainer:
+Eric Blake
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/modules/mknod-tests	Wed Nov 11 13:23:04 2009 -0700
@@ -0,0 +1,13 @@
+Files:
+tests/test-mkfifo.h
+tests/test-mknod.c
+
+Depends-on:
+stdbool
+symlink
+
+configure.ac:
+
+Makefile.am:
+TESTS += test-mknod
+check_PROGRAMS += test-mknod
--- a/modules/sys_stat	Wed Nov 11 13:22:04 2009 -0700
+++ b/modules/sys_stat	Wed Nov 11 13:23:04 2009 -0700
@@ -35,6 +35,7 @@
 	      -e 's|@''GNULIB_MKDIRAT''@|$(GNULIB_MKDIRAT)|g' \
 	      -e 's|@''GNULIB_MKFIFO''@|$(GNULIB_MKFIFO)|g' \
 	      -e 's|@''GNULIB_MKFIFOAT''@|$(GNULIB_MKFIFOAT)|g' \
+	      -e 's|@''GNULIB_MKNOD''@|$(GNULIB_MKNOD)|g' \
 	      -e 's|@''GNULIB_MKNODAT''@|$(GNULIB_MKNODAT)|g' \
 	      -e 's|@''GNULIB_STAT''@|$(GNULIB_STAT)|g' \
 	      -e 's|@''GNULIB_UTIMENSAT''@|$(GNULIB_UTIMENSAT)|g' \
@@ -46,6 +47,7 @@
 	      -e 's|@''HAVE_MKDIRAT''@|$(HAVE_MKDIRAT)|g' \
 	      -e 's|@''HAVE_MKFIFO''@|$(HAVE_MKFIFO)|g' \
 	      -e 's|@''HAVE_MKFIFOAT''@|$(HAVE_MKFIFOAT)|g' \
+	      -e 's|@''HAVE_MKNOD''@|$(HAVE_MKNOD)|g' \
 	      -e 's|@''HAVE_MKNODAT''@|$(HAVE_MKNODAT)|g' \
 	      -e 's|@''HAVE_UTIMENSAT''@|$(HAVE_UTIMENSAT)|g' \
 	      -e 's|@''REPLACE_FSTAT''@|$(REPLACE_FSTAT)|g' \
@@ -54,6 +56,7 @@
 	      -e 's|@''REPLACE_LSTAT''@|$(REPLACE_LSTAT)|g' \
 	      -e 's|@''REPLACE_MKDIR''@|$(REPLACE_MKDIR)|g' \
 	      -e 's|@''REPLACE_MKFIFO''@|$(REPLACE_MKFIFO)|g' \
+	      -e 's|@''REPLACE_MKNOD''@|$(REPLACE_MKNOD)|g' \
 	      -e 's|@''REPLACE_STAT''@|$(REPLACE_STAT)|g' \
 	      -e 's|@''REPLACE_UTIMENSAT''@|$(REPLACE_UTIMENSAT)|g' \
 	      -e '/definition of GL_LINK_WARNING/r $(LINK_WARNING_H)' \
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/tests/test-mknod.c	Wed Nov 11 13:23:04 2009 -0700
@@ -0,0 +1,62 @@
+/* Tests of mknod.
+   Copyright (C) 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 Eric Blake <ebb9@byu.net>, 2009.  */
+
+#include <config.h>
+
+#include <sys/stat.h>
+
+#include <fcntl.h>
+#include <errno.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+#define ASSERT(expr) \
+  do                                                                         \
+    {                                                                        \
+      if (!(expr))                                                           \
+        {                                                                    \
+          fprintf (stderr, "%s:%d: assertion failed\n", __FILE__, __LINE__);  \
+          fflush (stderr);                                                   \
+          abort ();                                                          \
+        }                                                                    \
+    }                                                                        \
+  while (0)
+
+#define BASE "test-mknod.t"
+
+#include "test-mkfifo.h"
+
+/* Wrapper around mknod, to create fifos.  */
+static int
+do_mknod (char const *name, mode_t mode)
+{
+  return mknod (name, mode | S_IFIFO, 0);
+}
+
+int
+main (void)
+{
+  /* Remove any leftovers from a previous partial run.  */
+  ASSERT (system ("rm -rf " BASE "*") == 0);
+
+  /* We can only portably test creation of fifos.  Anything else
+     requires root privileges and knowledge of device numbers.  */
+  return test_mkfifo (do_mknod, true);
+}