/contrib/groff/src/libs/libgroff/tmpname.cpp
https://bitbucket.org/freebsd/freebsd-head/ · C++ · 116 lines · 65 code · 21 blank · 30 comment · 8 complexity · 04900b5ef967a21642050d7fa92d3b77 MD5 · raw file
- /* Copyright (C) 2001, 2003, 2004 Free Software Foundation, Inc.
- Written by Werner Lemberg (wl@gnu.org)
- This file is part of groff.
- groff 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.
- groff 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 groff; see the file COPYING. If not, write to the Free Software
- Foundation, 51 Franklin St - Fifth Floor, Boston, MA 02110-1301, USA. */
- /* This file is heavily based on the function __gen_tempname() in the
- file tempname.c which is part of the fileutils package. */
- #include "lib.h"
- #include <stddef.h>
- #include <stdlib.h>
- #include <errno.h>
- #include <time.h>
- #include "posix.h"
- #include "nonposix.h"
- #ifndef TMP_MAX
- # define TMP_MAX 238328
- #endif
- #if HAVE_SYS_TIME_H
- # include <sys/time.h>
- #endif
- #ifdef HAVE_GETTIMEOFDAY
- #ifdef NEED_DECLARATION_GETTIMEOFDAY
- extern "C" {
- int gettimeofday(struct timeval *, void *);
- }
- #endif
- #endif
- #if HAVE_CC_INTTYPES_H
- # include <inttypes.h>
- #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";
- int gen_tempname(char *tmpl, int dir)
- {
- static uint64_t value;
- size_t len = strlen(tmpl);
- if (len < 6 || strcmp(&tmpl[len - 6], "XXXXXX"))
- return -1; /* EINVAL */
- /* This is where the Xs start. */
- char *XXXXXX = &tmpl[len - 6];
- /* Get some more or less random data. */
- #if HAVE_GETTIMEOFDAY
- timeval tv;
- gettimeofday(&tv, NULL);
- uint64_t random_time_bits = ((uint64_t)tv.tv_usec << 16) ^ tv.tv_sec;
- #else
- uint64_t random_time_bits = time(NULL);
- #endif
- value += random_time_bits ^ getpid();
- for (int count = 0; count < TMP_MAX; 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];
- int fd = dir ? mkdir(tmpl, S_IRUSR | S_IWUSR | S_IXUSR)
- : open(tmpl, O_RDWR | O_CREAT | O_EXCL, S_IRUSR | S_IWUSR);
- if (fd >= 0)
- return fd;
- else if (errno != EEXIST)
- return -1;
- }
- /* We got out of the loop because we ran out of combinations to try. */
- return -1; /* EEXIST */
- }