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/* Copyright (C) 1991,92,93,94,95,96,97,98,99 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Library General Public License as
published by the Free Software Foundation; either version 2 of the
License, or (at your option) any later version.
The GNU C Library 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
Library General Public License for more details.
You should have received a copy of the GNU Library General Public
License along with the GNU C Library; see the file COPYING.LIB. If not,
see <http://www.gnu.org/licenses/>. */
/* March 11, 2002 Manuel Novoa III
*
* Modify code to remove dependency on libgcc long long arith support funcs.
*/
/* June 6, 2004 Erik Andersen
*
* Don't use brain damaged getpid() based randomness.
*/
/* April 15, 2005 Mike Frysinger
*
* Use brain damaged getpid() if real random fails.
*/
#include <stddef.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <fcntl.h>
#include <unistd.h>
#include <assert.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/time.h>
#include "tempname.h"
/* Return nonzero if DIR is an existent directory. */
static int direxists (const char *dir)
{
struct stat buf;
return stat(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; */
/* dir and pfx lengths should always fit into an int,
so don't bother using size_t here. Especially since
the printf func requires an int for precision (%*s). */
int dlen, plen;
if (!pfx || !pfx[0])
{
pfx = "file";
plen = 4;
}
else
{
plen = strlen (pfx);
if (plen > 5)
plen = 5;
}
/* Disable support for $TMPDIR */
#if 0
if (try_tmpdir)
{
d = __secure_getenv ("TMPDIR");
if (d != NULL && direxists (d))
dir = d;
else if (dir != NULL && direxists (dir))
/* nothing */ ;
else
dir = NULL;
}
#endif
if (dir == NULL)
{
if (direxists (P_tmpdir))
dir = P_tmpdir;
else if (strcmp (P_tmpdir, "/tmp") != 0 && direxists ("/tmp"))
dir = "/tmp";
else
{
__set_errno (ENOENT);
return -1;
}
}
dlen = strlen (dir);
while (dlen > 1 && dir[dlen - 1] == '/')
dlen--; /* remove trailing slashes */
/* check we have room for "${dir}/${pfx}XXXXXX\0" */
if (tmpl_len < (size_t)dlen + 1 + plen + 6 + 1)
{
__set_errno (EINVAL);
return -1;
}
sprintf (tmpl, "%.*s/%.*sXXXXXX", dlen, dir, plen, pfx);
return 0;
}
/* These are the characters used in temporary filenames. */
static const char letters[] =
"abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";
#define NUM_LETTERS (62)
static unsigned int fillrand(unsigned char *buf, unsigned int len)
{
int fd;
unsigned int result = -1;
fd = open("/dev/urandom", O_RDONLY);
if (fd < 0) {
fd = open("/dev/random", O_RDONLY | O_NONBLOCK);
}
if (fd >= 0) {
result = read(fd, buf, len);
close(fd);
}
return result;
}
static void brain_damaged_fillrand(unsigned char *buf, unsigned int len)
{
unsigned int i, k;
struct timeval tv;
uint32_t high, low, rh;
static uint64_t value;
gettimeofday(&tv, NULL);
value += ((uint64_t) tv.tv_usec << 16) ^ tv.tv_sec ^ getpid();
low = value & UINT32_MAX;
high = value >> 32;
for (i = 0; i < len; ++i) {
rh = high % NUM_LETTERS;
high /= NUM_LETTERS;
#define L ((UINT32_MAX % NUM_LETTERS + 1) % NUM_LETTERS)
k = (low % NUM_LETTERS) + (L * rh);
#undef L
#define H ((UINT32_MAX / NUM_LETTERS) + ((UINT32_MAX % NUM_LETTERS + 1) / NUM_LETTERS))
low = (low / NUM_LETTERS) + (H * rh) + (k / NUM_LETTERS);
#undef H
k %= NUM_LETTERS;
buf[i] = letters[k];
}
}
/* Generate a temporary file name based on TMPL. TMPL must match the
rules for mk[s]temp[s] (i.e. end in "prefixXXXXXXsuffix"). 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. mode argument is ignored.
__GT_FILE: create the file using open(O_CREAT|O_EXCL)
and return a read-write fd with given mode.
__GT_BIGFILE: same as __GT_FILE but use open64().
__GT_DIR: create a directory with given mode.
*/
int attribute_hidden __gen_tempname (char *tmpl, int kind, int flags,
int suffixlen, mode_t mode)
{
char *XXXXXX;
unsigned int i;
int fd, save_errno = errno;
unsigned char randomness[6];
size_t len;
len = strlen (tmpl);
/* This is where the Xs start. */
XXXXXX = tmpl + len - 6 - suffixlen;
if (len < 6 || suffixlen < 0 || suffixlen > len - 6
|| strncmp (XXXXXX, "XXXXXX", 6))
{
__set_errno (EINVAL);
return -1;
}
for (i = 0; i < TMP_MAX; ++i) {
unsigned char j;
/* Get some random data. */
if (fillrand(randomness, sizeof(randomness)) != sizeof(randomness)) {
/* if random device nodes failed us, lets use the braindamaged ver */
brain_damaged_fillrand(randomness, sizeof(randomness));
}
for (j = 0; j < sizeof(randomness); ++j)
XXXXXX[j] = letters[randomness[j] % NUM_LETTERS];
switch (kind) {
case __GT_NOCREATE:
{
struct stat st;
if (stat (tmpl, &st) < 0) {
if (errno == ENOENT) {
fd = 0;
goto restore_and_ret;
} else
/* Give up now. */
return -1;
} else
fd = 0;
}
case __GT_FILE:
fd = open (tmpl, O_RDWR | O_CREAT | O_EXCL | flags, mode);
break;
case __GT_BIGFILE:
fd = open64 (tmpl, O_RDWR | O_CREAT | O_EXCL | flags, mode);
break;
case __GT_DIR:
fd = mkdir (tmpl, mode);
break;
default:
fd = -1;
assert (! "invalid KIND in __gen_tempname");
}
if (fd >= 0) {
restore_and_ret:
__set_errno (save_errno);
return fd;
}
else if (errno != EEXIST)
/* Any other error will apply also to other names we might
try, and there are 2^32 or so of them, so give up now. */
return -1;
}
/* We got out of the loop because we ran out of combinations to try. */
__set_errno (EEXIST);
return -1;
}
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