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72c65ff44b
2000-09-11 Ulrich Drepper <drepper@redhat.com> * sysdeps/posix/tempname.c (__gen_tempname): Use __lxstat and __xstat.
212 lines
5.4 KiB
C
212 lines
5.4 KiB
C
/* Copyright (C) 1991-1999, 2000 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Library General Public License as
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published by the Free Software Foundation; either version 2 of the
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License, or (at your option) any later version.
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The GNU C Library 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 GNU
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Library General Public License for more details.
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You should have received a copy of the GNU Library General Public
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License along with the GNU C Library; see the file COPYING.LIB. If not,
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write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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Boston, MA 02111-1307, USA. */
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#include <stddef.h>
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#include <stdint.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <errno.h>
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#include <sys/types.h>
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#include <sys/stat.h>
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#include <fcntl.h>
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#include <unistd.h>
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#include <sys/time.h>
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#include <assert.h>
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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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/* These are the characters used in temporary filenames. */
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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 match the
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rules for mk[s]temp (i.e. end in "XXXXXX"). 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_BIGFILE: same as __GT_FILE but use open64().
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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 (char *tmpl, int kind)
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{
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int len;
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char *XXXXXX;
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static uint64_t value;
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struct timeval tv;
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int count, fd = -1;
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int save_errno = errno;
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struct stat64 st;
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len = strlen (tmpl);
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if (len < 6 || strcmp (&tmpl[len - 6], "XXXXXX"))
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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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/* This is where the Xs start. */
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XXXXXX = &tmpl[len - 6];
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/* Get some more or less random data. */
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__gettimeofday (&tv, NULL);
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value += ((uint64_t) tv.tv_usec << 16) ^ tv.tv_sec ^ __getpid ();
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for (count = 0; count < TMP_MAX; value += 7777, ++count)
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{
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uint64_t v = value;
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/* Fill in the random bits. */
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XXXXXX[0] = letters[v % 62];
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v /= 62;
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XXXXXX[1] = letters[v % 62];
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v /= 62;
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XXXXXX[2] = letters[v % 62];
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v /= 62;
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XXXXXX[3] = letters[v % 62];
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v /= 62;
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XXXXXX[4] = letters[v % 62];
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v /= 62;
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XXXXXX[5] = letters[v % 62];
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switch (kind)
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{
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case __GT_FILE:
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fd = __open (tmpl, O_RDWR | O_CREAT | O_EXCL, 0600);
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break;
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case __GT_BIGFILE:
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fd = __open64 (tmpl, O_RDWR | O_CREAT | O_EXCL, 0600);
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break;
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case __GT_DIR:
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fd = __mkdir (tmpl, 0700);
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break;
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case __GT_NOCREATE:
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/* This case is backward from the other three. __gen_tempname
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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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return 0;
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}
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else
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/* Give up now. */
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return -1;
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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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return fd;
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}
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else if (errno != EEXIST)
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return -1;
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}
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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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}
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