Copy from gnulib the parts of tempname that we'll modify.

* gl/lib/tempname.c: Copy from gnulib.
* gl/lib/tempname.h: Likewise.
* gl/modules/tempname: Likewise.

Allow GPLv2 on temporarily(?)-imported file from gnulib/libc.
* .x-sc_GPL_version: New file.
* Makefile.am (EXTRA_DIST): Add .x-sc_GPL_version

3 files changed, 383 insertions, 0 deletions

diff --git a/gl/lib/tempname.c b/gl/lib/tempname.c
new file mode 100644
index 000000000..e213600e3
--- /dev/null
+++ b/gl/lib/tempname.c
@@ -0,0 +1,315 @@
+/* tempname.c - generate the name of a temporary file.
+
+   Copyright (C) 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999,
+   2000, 2001, 2002, 2003, 2005, 2006, 2007 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 2, 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, write to the Free Software Foundation,
+   Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.  */
+
+/* Extracted from glibc sysdeps/posix/tempname.c.  See also tmpdir.c.  */
+
+#if !_LIBC
+# include <config.h>
+# include "tempname.h"
+#endif
+
+#include <sys/types.h>
+#include <assert.h>
+
+#include <errno.h>
+#ifndef __set_errno
+# define __set_errno(Val) errno = (Val)
+#endif
+
+#include <stdio.h>
+#ifndef P_tmpdir
+# define P_tmpdir "/tmp"
+#endif
+#ifndef TMP_MAX
+# define TMP_MAX 238328
+#endif
+#ifndef __GT_FILE
+# define __GT_FILE	0
+# define __GT_BIGFILE	1
+# define __GT_DIR	2
+# define __GT_NOCREATE	3
+#endif
+
+#include <stddef.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include <fcntl.h>
+#include <sys/time.h>
+#include <stdint.h>
+#include <unistd.h>
+
+#include <sys/stat.h>
+
+#if _LIBC
+# define struct_stat64 struct stat64
+# define small_open __open
+# define large_open __open64
+#else
+# define struct_stat64 struct stat
+# define small_open open
+# define large_open open
+# define __gen_tempname gen_tempname
+# define __getpid getpid
+# define __gettimeofday gettimeofday
+# define __mkdir mkdir
+# define __lxstat64(version, file, buf) lstat (file, buf)
+# define __xstat64(version, file, buf) stat (file, buf)
+#endif
+
+#if ! (HAVE___SECURE_GETENV || _LIBC)
+# define __secure_getenv getenv
+#endif
+
+#ifdef _LIBC
+# include <hp-timing.h>
+# if HP_TIMING_AVAIL
+#  define RANDOM_BITS(Var) \
+  if (__builtin_expect (value == UINT64_C (0), 0))			      \
+    {									      \
+      /* If this is the first time this function is used initialize	      \
+	 the variable we accumulate the value in to some somewhat	      \
+	 random value.  If we'd not do this programs at startup time	      \
+	 might have a reduced set of possible names, at least on slow	      \
+	 machines.  */							      \
+      struct timeval tv;						      \
+      __gettimeofday (&tv, NULL);					      \
+      value = ((uint64_t) tv.tv_usec << 16) ^ tv.tv_sec;		      \
+    }									      \
+  HP_TIMING_NOW (Var)
+# endif
+#endif
+
+/* Use the widest available unsigned type if uint64_t is not
+   available.  The algorithm below extracts a number less than 62**6
+   (approximately 2**35.725) from uint64_t, so ancient hosts where
+   uintmax_t is only 32 bits lose about 3.725 bits of randomness,
+   which is better than not having mkstemp at all.  */
+#if !defined UINT64_MAX && !defined uint64_t
+# define uint64_t uintmax_t
+#endif
+
+#if _LIBC
+/* Return nonzero if DIR is an existent directory.  */
+static int
+direxists (const char *dir)
+{
+  struct_stat64 buf;
+  return __xstat64 (_STAT_VER, dir, &buf) == 0 && S_ISDIR (buf.st_mode);
+}
+
+/* Path search algorithm, for tmpnam, tmpfile, etc.  If DIR is
+   non-null and exists, uses it; otherwise uses the first of $TMPDIR,
+   P_tmpdir, /tmp that exists.  Copies into TMPL a template suitable
+   for use with mk[s]temp.  Will fail (-1) if DIR is non-null and
+   doesn't exist, none of the searched dirs exists, or there's not
+   enough space in TMPL. */
+int
+__path_search (char *tmpl, size_t tmpl_len, const char *dir, const char *pfx,
+	       int try_tmpdir)
+{
+  const char *d;
+  size_t dlen, plen;
+
+  if (!pfx || !pfx[0])
+    {
+      pfx = "file";
+      plen = 4;
+    }
+  else
+    {
+      plen = strlen (pfx);
+      if (plen > 5)
+	plen = 5;
+    }
+
+  if (try_tmpdir)
+    {
+      d = __secure_getenv ("TMPDIR");
+      if (d != NULL && direxists (d))
+	dir = d;
+      else if (dir != NULL && direxists (dir))
+	/* nothing */ ;
+      else
+	dir = NULL;
+    }
+  if (dir == NULL)
+    {
+      if (direxists (P_tmpdir))
+	dir = P_tmpdir;
+      else if (strcmp (P_tmpdir, "/tmp") != 0 && direxists ("/tmp"))
+	dir = "/tmp";
+      else
+	{
+	  __set_errno (ENOENT);
+	  return -1;
+	}
+    }
+
+  dlen = strlen (dir);
+  while (dlen > 1 && dir[dlen - 1] == '/')
+    dlen--;			/* remove trailing slashes */
+
+  /* check we have room for "${dir}/${pfx}XXXXXX\0" */
+  if (tmpl_len < dlen + 1 + plen + 6 + 1)
+    {
+      __set_errno (EINVAL);
+      return -1;
+    }
+
+  sprintf (tmpl, "%.*s/%.*sXXXXXX", (int) dlen, dir, (int) plen, pfx);
+  return 0;
+}
+#endif /* _LIBC */
+
+/* These are the characters used in temporary file names.  */
+static const char letters[] =
+"abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";
+
+/* Generate a temporary file name based on TMPL.  TMPL must match the
+   rules for mk[s]temp (i.e. end in "XXXXXX").  The name constructed
+   does not exist at the time of the call to __gen_tempname.  TMPL is
+   overwritten with the result.
+
+   KIND may be one of:
+   __GT_NOCREATE:	simply verify that the name does not exist
+			at the time of the call.
+   __GT_FILE:		create the file using open(O_CREAT|O_EXCL)
+			and return a read-write fd.  The file is mode 0600.
+   __GT_BIGFILE:	same as __GT_FILE but use open64().
+   __GT_DIR:		create a directory, which will be mode 0700.
+
+   We use a clever algorithm to get hard-to-predict names. */
+int
+__gen_tempname (char *tmpl, int kind)
+{
+  int len;
+  char *XXXXXX;
+  static uint64_t value;
+  uint64_t random_time_bits;
+  unsigned int count;
+  int fd = -1;
+  int save_errno = errno;
+  struct_stat64 st;
+
+  /* A lower bound on the number of temporary files to attempt to
+     generate.  The maximum total number of temporary file names that
+     can exist for a given template is 62**6.  It should never be
+     necessary to try all these combinations.  Instead if a reasonable
+     number of names is tried (we define reasonable as 62**3) fail to
+     give the system administrator the chance to remove the problems.  */
+#define ATTEMPTS_MIN (62 * 62 * 62)
+
+  /* The number of times to attempt to generate a temporary file.  To
+     conform to POSIX, this must be no smaller than TMP_MAX.  */
+#if ATTEMPTS_MIN < TMP_MAX
+  unsigned int attempts = TMP_MAX;
+#else
+  unsigned int attempts = ATTEMPTS_MIN;
+#endif
+
+  len = strlen (tmpl);
+  if (len < 6 || strcmp (&tmpl[len - 6], "XXXXXX"))
+    {
+      __set_errno (EINVAL);
+      return -1;
+    }
+
+  /* This is where the Xs start.  */
+  XXXXXX = &tmpl[len - 6];
+
+  /* Get some more or less random data.  */
+#ifdef RANDOM_BITS
+  RANDOM_BITS (random_time_bits);
+#else
+  {
+    struct timeval tv;
+    __gettimeofday (&tv, NULL);
+    random_time_bits = ((uint64_t) tv.tv_usec << 16) ^ tv.tv_sec;
+  }
+#endif
+  value += random_time_bits ^ __getpid ();
+
+  for (count = 0; count < attempts; value += 7777, ++count)
+    {
+      uint64_t v = value;
+
+      /* Fill in the random bits.  */
+      XXXXXX[0] = letters[v % 62];
+      v /= 62;
+      XXXXXX[1] = letters[v % 62];
+      v /= 62;
+      XXXXXX[2] = letters[v % 62];
+      v /= 62;
+      XXXXXX[3] = letters[v % 62];
+      v /= 62;
+      XXXXXX[4] = letters[v % 62];
+      v /= 62;
+      XXXXXX[5] = letters[v % 62];
+
+      switch (kind)
+	{
+	case __GT_FILE:
+	  fd = small_open (tmpl, O_RDWR | O_CREAT | O_EXCL, S_IRUSR | S_IWUSR);
+	  break;
+
+	case __GT_BIGFILE:
+	  fd = large_open (tmpl, O_RDWR | O_CREAT | O_EXCL, S_IRUSR | S_IWUSR);
+	  break;
+
+	case __GT_DIR:
+	  fd = __mkdir (tmpl, S_IRUSR | S_IWUSR | S_IXUSR);
+	  break;
+
+	case __GT_NOCREATE:
+	  /* This case is backward from the other three.  __gen_tempname
+	     succeeds if __xstat fails because the name does not exist.
+	     Note the continue to bypass the common logic at the bottom
+	     of the loop.  */
+	  if (__lxstat64 (_STAT_VER, tmpl, &st) < 0)
+	    {
+	      if (errno == ENOENT)
+		{
+		  __set_errno (save_errno);
+		  return 0;
+		}
+	      else
+		/* Give up now. */
+		return -1;
+	    }
+	  continue;
+
+	default:
+	  assert (! "invalid KIND in __gen_tempname");
+	}
+
+      if (fd >= 0)
+	{
+	  __set_errno (save_errno);
+	  return fd;
+	}
+      else if (errno != EEXIST)
+	return -1;
+    }
+
+  /* We got out of the loop because we ran out of combinations to try.  */
+  __set_errno (EEXIST);
+  return -1;
+}
diff --git a/gl/lib/tempname.h b/gl/lib/tempname.h
new file mode 100644
index 000000000..c51fa6942
--- /dev/null
+++ b/gl/lib/tempname.h
@@ -0,0 +1,40 @@
+/* Create a temporary file or directory.
+
+   Copyright (C) 2006 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 2, 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, write to the Free Software Foundation,
+   Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.  */
+
+/* header written by Eric Blake */
+
+/* In gnulib, always prefer large files.  GT_FILE maps to
+   __GT_BIGFILE, not __GT_FILE, for a reason.  */
+#define GT_FILE		1
+#define GT_DIR		2
+#define GT_NOCREATE	3
+
+/* Generate a temporary file name based on TMPL.  TMPL must match the
+   rules for mk[s]temp (i.e. end in "XXXXXX").  The name constructed
+   does not exist at the time of the call to gen_tempname.  TMPL is
+   overwritten with the result.
+
+   KIND may be one of:
+   GT_NOCREATE:		simply verify that the name does not exist
+			at the time of the call.
+   GT_FILE:		create a large file using open(O_CREAT|O_EXCL)
+			and return a read-write fd.  The file is mode 0600.
+   GT_DIR:		create a directory, which will be mode 0700.
+
+   We use a clever algorithm to get hard-to-predict names. */
+extern int gen_tempname (char *tmpl, int kind);
diff --git a/gl/modules/tempname b/gl/modules/tempname
new file mode 100644
index 000000000..af689de6f
--- /dev/null
+++ b/gl/modules/tempname
@@ -0,0 +1,28 @@
+Description:
+gen_tempname() function: create a private temporary file or directory.
+
+Files:
+lib/tempname.c
+lib/tempname.h
+m4/tempname.m4
+
+Depends-on:
+extensions
+gettimeofday
+stdint
+sys_stat
+sys_time
+
+configure.ac:
+gl_FUNC_GEN_TEMPNAME
+
+Makefile.am:
+
+Include:
+"tempname.h"
+
+License:
+LGPL
+
+Maintainer:
+Eric Blake and Jim Meyering