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99f59aaaf8
* src/mktemp.c (mkstemp_len, mkdtemp_len): Update callers of gen_tempname_len. * gl/lib/tempname.c, gl/lib/tempname.h: Rebase against recently API-modified copy of tempname module in gnulib. Reported by Lluís Batlle.
295 lines
7.6 KiB
C
295 lines
7.6 KiB
C
/* tempname.c - generate the name of a temporary file.
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Copyright (C) 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999,
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2000, 2001, 2002, 2003, 2005, 2006, 2007, 2009 Free Software Foundation,
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Inc.
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This program is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>. */
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/* Extracted from glibc sysdeps/posix/tempname.c. See also tmpdir.c. */
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#if !_LIBC
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# include <config.h>
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# include "tempname.h"
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# include "randint.h"
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#endif
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#include <sys/types.h>
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#include <assert.h>
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#include <errno.h>
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#ifndef __set_errno
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# define __set_errno(Val) errno = (Val)
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#endif
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#include <stdio.h>
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#ifndef P_tmpdir
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# define P_tmpdir "/tmp"
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#endif
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#ifndef TMP_MAX
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# define TMP_MAX 238328
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#endif
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#ifndef __GT_FILE
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# define __GT_FILE 1
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# define __GT_DIR 2
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# define __GT_NOCREATE 3
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#endif
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#include <stdbool.h>
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#include <stddef.h>
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#include <stdlib.h>
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#include <string.h>
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#include <fcntl.h>
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#include <sys/time.h>
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#include <stdint.h>
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#include <unistd.h>
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#include <sys/stat.h>
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#if _LIBC
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# define struct_stat64 struct stat64
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#else
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# define struct_stat64 struct stat
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# define __open open
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# define __gen_tempname gen_tempname
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# define __getpid getpid
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# define __gettimeofday gettimeofday
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# define __mkdir mkdir
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# define __lxstat64(version, file, buf) lstat (file, buf)
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# define __xstat64(version, file, buf) stat (file, buf)
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#endif
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#if ! (HAVE___SECURE_GETENV || _LIBC)
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# define __secure_getenv getenv
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#endif
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#if _LIBC
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/* Return nonzero if DIR is an existent directory. */
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static int
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direxists (const char *dir)
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{
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struct_stat64 buf;
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return __xstat64 (_STAT_VER, dir, &buf) == 0 && S_ISDIR (buf.st_mode);
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}
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/* Path search algorithm, for tmpnam, tmpfile, etc. If DIR is
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non-null and exists, uses it; otherwise uses the first of $TMPDIR,
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P_tmpdir, /tmp that exists. Copies into TMPL a template suitable
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for use with mk[s]temp. Will fail (-1) if DIR is non-null and
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doesn't exist, none of the searched dirs exists, or there's not
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enough space in TMPL. */
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int
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__path_search (char *tmpl, size_t tmpl_len, const char *dir, const char *pfx,
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int try_tmpdir)
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{
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const char *d;
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size_t dlen, plen;
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if (!pfx || !pfx[0])
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{
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pfx = "file";
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plen = 4;
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}
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else
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{
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plen = strlen (pfx);
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if (plen > 5)
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plen = 5;
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}
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if (try_tmpdir)
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{
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d = __secure_getenv ("TMPDIR");
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if (d != NULL && direxists (d))
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dir = d;
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else if (dir != NULL && direxists (dir))
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/* nothing */ ;
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else
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dir = NULL;
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}
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if (dir == NULL)
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{
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if (direxists (P_tmpdir))
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dir = P_tmpdir;
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else if (strcmp (P_tmpdir, "/tmp") != 0 && direxists ("/tmp"))
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dir = "/tmp";
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else
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{
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__set_errno (ENOENT);
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return -1;
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}
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}
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dlen = strlen (dir);
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while (dlen > 1 && dir[dlen - 1] == '/')
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dlen--; /* remove trailing slashes */
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/* check we have room for "${dir}/${pfx}XXXXXX\0" */
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if (tmpl_len < dlen + 1 + plen + 6 + 1)
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{
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__set_errno (EINVAL);
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return -1;
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}
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sprintf (tmpl, "%.*s/%.*sXXXXXX", (int) dlen, dir, (int) plen, pfx);
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return 0;
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}
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#endif /* _LIBC */
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static inline bool
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check_x_suffix (char const *s, size_t len)
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{
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return strspn (s, "X") == len;
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}
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/* These are the characters used in temporary file names. */
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static const char letters[] =
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"abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";
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/* Generate a temporary file name based on TMPL. TMPL must end in a
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a sequence of at least X_SUFFIX_LEN "X"s. The name constructed
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does not exist at the time of the call to __gen_tempname. TMPL is
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overwritten with the result.
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KIND may be one of:
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__GT_NOCREATE: simply verify that the name does not exist
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at the time of the call.
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__GT_FILE: create the file using open(O_CREAT|O_EXCL)
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and return a read-write fd. The file is mode 0600.
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__GT_DIR: create a directory, which will be mode 0700.
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We use a clever algorithm to get hard-to-predict names. */
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int
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gen_tempname_len (char *tmpl, int flags, int kind, size_t x_suffix_len)
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{
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size_t len;
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char *XXXXXX;
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unsigned int count;
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int fd = -1;
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int save_errno = errno;
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struct_stat64 st;
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struct randint_source *rand_src;
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/* A lower bound on the number of temporary files to attempt to
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generate. The maximum total number of temporary file names that
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can exist for a given template is 62**6. It should never be
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necessary to try all these combinations. Instead if a reasonable
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number of names is tried (we define reasonable as 62**3) fail to
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give the system administrator the chance to remove the problems. */
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#define ATTEMPTS_MIN (62 * 62 * 62)
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/* The number of times to attempt to generate a temporary file. To
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conform to POSIX, this must be no smaller than TMP_MAX. */
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#if ATTEMPTS_MIN < TMP_MAX
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unsigned int attempts = TMP_MAX;
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#else
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unsigned int attempts = ATTEMPTS_MIN;
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#endif
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len = strlen (tmpl);
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if (len < x_suffix_len || ! check_x_suffix (&tmpl[len - x_suffix_len],
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x_suffix_len))
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{
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__set_errno (EINVAL);
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return -1;
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}
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rand_src = randint_all_new (NULL, 8);
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if (! rand_src)
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return -1;
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/* This is where the Xs start. */
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XXXXXX = &tmpl[len - x_suffix_len];
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for (count = 0; count < attempts; ++count)
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{
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size_t i;
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for (i = 0; i < x_suffix_len; i++)
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{
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XXXXXX[i] = letters[randint_genmax (rand_src, sizeof letters - 2)];
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}
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switch (kind)
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{
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case __GT_FILE:
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fd = __open (tmpl,
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(flags & ~0777) | O_RDWR | O_CREAT | O_EXCL,
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S_IRUSR | S_IWUSR);
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break;
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case __GT_DIR:
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fd = __mkdir (tmpl, S_IRUSR | S_IWUSR | S_IXUSR);
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break;
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case __GT_NOCREATE:
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/* This case is backward from the other three. This function
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succeeds if __xstat fails because the name does not exist.
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Note the continue to bypass the common logic at the bottom
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of the loop. */
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if (__lxstat64 (_STAT_VER, tmpl, &st) < 0)
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{
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if (errno == ENOENT)
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{
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__set_errno (save_errno);
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fd = 0;
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goto done;
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}
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else
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{
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/* Give up now. */
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fd = -1;
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goto done;
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}
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}
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continue;
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default:
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assert (! "invalid KIND in __gen_tempname");
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}
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if (fd >= 0)
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{
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__set_errno (save_errno);
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goto done;
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}
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else if (errno != EEXIST)
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{
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fd = -1;
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goto done;
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}
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}
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randint_all_free (rand_src);
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/* We got out of the loop because we ran out of combinations to try. */
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__set_errno (EEXIST);
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return -1;
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done:
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{
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int saved_errno = errno;
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randint_all_free (rand_src);
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__set_errno (saved_errno);
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}
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return fd;
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}
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int
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__gen_tempname (char *tmpl, int flags, int kind)
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{
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return gen_tempname_len (tmpl, flags, kind, 6);
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}
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