diff options
Diffstat (limited to 'gl/mkdtemp.c')
-rw-r--r-- | gl/mkdtemp.c | 208 |
1 files changed, 208 insertions, 0 deletions
diff --git a/gl/mkdtemp.c b/gl/mkdtemp.c new file mode 100644 index 0000000..4cf86a0 --- /dev/null +++ b/gl/mkdtemp.c @@ -0,0 +1,208 @@ +/* Copyright (C) 1999, 2001-2003, 2006 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + 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, 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/>. */ + +/* Extracted from misc/mkdtemp.c and sysdeps/posix/tempname.c. */ + +#include <config.h> + +/* Specification. */ +#include "mkdtemp.h" + +#include <errno.h> +#ifndef __set_errno +# define __set_errno(Val) errno = (Val) +#endif + +#include <stddef.h> +#include <stdint.h> +#include <stdlib.h> +#include <string.h> + +#include <stdio.h> +#ifndef TMP_MAX +# define TMP_MAX 238328 +#endif + +#include <unistd.h> + +#if HAVE_GETTIMEOFDAY || _LIBC +# if HAVE_SYS_TIME_H || _LIBC +# include <sys/time.h> +# endif +#else +# if HAVE_TIME_H || _LIBC +# include <time.h> +# endif +#endif + +#include <sys/stat.h> +#if !defined S_ISDIR && defined S_IFDIR +# define S_ISDIR(mode) (((mode) & S_IFMT) == S_IFDIR) +#endif +#if !S_IRUSR && S_IREAD +# define S_IRUSR S_IREAD +#endif +#if !S_IRUSR +# define S_IRUSR 00400 +#endif +#if !S_IWUSR && S_IWRITE +# define S_IWUSR S_IWRITE +#endif +#if !S_IWUSR +# define S_IWUSR 00200 +#endif +#if !S_IXUSR && S_IEXEC +# define S_IXUSR S_IEXEC +#endif +#if !S_IXUSR +# define S_IXUSR 00100 +#endif + +#ifdef __MINGW32__ +# include <io.h> +#endif + +#if !_LIBC +# define __getpid getpid +# define __gettimeofday gettimeofday +# define __mkdir mkdir +#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 + +/* These are the characters used in temporary filenames. */ +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 is: + __GT_DIR: create a directory, which will be mode 0700. + + We use a clever algorithm to get hard-to-predict names. */ +static int +gen_tempname (char *tmpl) +{ + int len; + char *XXXXXX; + static uint64_t value; + uint64_t random_time_bits; + unsigned int count; + int fd = -1; + int save_errno = errno; + + /* 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 +# if HAVE_GETTIMEOFDAY || _LIBC + { + struct timeval tv; + __gettimeofday (&tv, NULL); + random_time_bits = ((uint64_t) tv.tv_usec << 16) ^ tv.tv_sec; + } +# else + random_time_bits = time (NULL); +# endif +#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]; + +#ifdef MKDIR_TAKES_ONE_ARG + fd = mkdir (tmpl); +#else + fd = __mkdir (tmpl, S_IRUSR | S_IWUSR | S_IXUSR); +#endif + + 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; +} + +/* Generate a unique temporary directory from TEMPLATE. + The last six characters of TEMPLATE must be "XXXXXX"; + they are replaced with a string that makes the filename unique. + The directory is created, mode 700, and its name is returned. + (This function comes from OpenBSD.) */ +char * +mkdtemp (char *template) +{ + if (gen_tempname (template)) + return NULL; + else + return template; +} |