mirror of
https://github.com/alsa-project/alsa-utils
synced 2024-09-19 17:49:59 +02:00
888275e66c
sprintf() is a bit dangerous unless you explicitly know your type size and want to keep it in sync always. Its safer to just use snprintf() and ensure your string doesn't overflow and is NULL terminated. Signed-off-by: Doug Goldstein <cardoe@cardoe.com> Signed-off-by: Takashi Iwai <tiwai@suse.de>
124 lines
2.7 KiB
C
124 lines
2.7 KiB
C
/*
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* Advanced Linux Sound Architecture Control Program
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* Copyright (c) by Jaroslav Kysela <perex@perex.cz>
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*
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*
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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 2 of the License, or
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* (at your option) any later version.
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*
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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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*
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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, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*
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*/
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#include "aconfig.h"
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#include "version.h"
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#include <stdio.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include <fcntl.h>
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#include <errno.h>
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#include <string.h>
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#include <sys/stat.h>
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#include "alsactl.h"
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static int state_lock_(const char *file, int lock, int timeout)
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{
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int fd = -1, err = 0;
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struct flock lck;
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struct stat st;
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char lcktxt[12];
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char *nfile;
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if (!do_lock)
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return 0;
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nfile = malloc(strlen(file) + 6);
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if (nfile == NULL) {
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error("No enough memory...");
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return -ENOMEM;
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}
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strcpy(nfile, file);
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strcat(nfile, ".lock");
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lck.l_type = lock ? F_WRLCK : F_UNLCK;
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lck.l_whence = SEEK_SET;
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lck.l_start = 0;
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lck.l_len = 11;
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lck.l_pid = 0;
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if (lock) {
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snprintf(lcktxt, sizeof(lcktxt), "%10li\n", (long)getpid());
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} else {
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snprintf(lcktxt, sizeof(lcktxt), "%10s\n", "");
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}
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while (fd < 0 && timeout-- > 0) {
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fd = open(nfile, O_RDWR);
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if (fd < 0) {
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fd = open(nfile, O_RDWR|O_CREAT|O_EXCL, 0644);
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if (fd < 0) {
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if (errno == EBUSY || errno == EAGAIN) {
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sleep(1);
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timeout--;
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} else {
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err = -errno;
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goto out;
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}
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}
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}
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}
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if (fd < 0 && timeout <= 0) {
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err = -EBUSY;
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goto out;
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}
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if (fstat(fd, &st) < 0) {
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err = -errno;
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goto out;
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}
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if (st.st_size != 11) {
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if (write(fd, lcktxt, 11) != 11) {
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err = -EIO;
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goto out;
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}
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if (lseek(fd, 0, SEEK_SET)) {
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err = -errno;
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goto out;
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}
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}
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while (timeout > 0) {
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if (fcntl(fd, F_SETLK, &lck) < 0) {
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sleep(1);
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timeout--;
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} else {
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break;
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}
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}
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if (timeout <= 0) {
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err = -EBUSY;
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goto out;
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}
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if (write(fd, lcktxt, 11) != 11) {
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err = -EIO;
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goto out;
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}
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out:
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free(nfile);
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return err;
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}
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int state_lock(const char *file, int lock, int timeout)
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{
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int err;
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err = state_lock_(file, lock, timeout);
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if (err < 0)
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error("file %s %slock error: %s", file,
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lock ? "" : "un", strerror(-err));
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return err;
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}
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