mirror_zfs/udev/zvol_id.c
rilysh 86737c5927
Avoid computing strlen() inside loops
Compiling with -O0 (no proper optimizations), strlen() call
in loops for comparing the size, isn't being called/initialized
before the actual loop gets started, which causes n-numbers of
strlen() calls (as long as the string is). Keeping the length
before entering in the loop is a good idea.

On some places, even with -O2, both GCC and Clang can't
recognize this pattern, which seem to happen in an array
of char pointer.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Alexander Motin <mav@FreeBSD.org>
Signed-off-by: rilysh <nightquick@proton.me>
Closes #16584
2024-10-02 09:10:06 -07:00

91 lines
2.4 KiB
C

/*
* CDDL HEADER START
*
* The contents of this file are subject to the terms of the
* Common Development and Distribution License (the "License").
* You may not use this file except in compliance with the License.
*
* You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
* or https://opensource.org/licenses/CDDL-1.0.
* See the License for the specific language governing permissions
* and limitations under the License.
*
* When distributing Covered Code, include this CDDL HEADER in each
* file and include the License file at usr/src/OPENSOLARIS.LICENSE.
* If applicable, add the following below this CDDL HEADER, with the
* fields enclosed by brackets "[]" replaced with your own identifying
* information: Portions Copyright [yyyy] [name of copyright owner]
*
* CDDL HEADER END
*/
/*
* Copyright (c) 2011, Fajar A. Nugraha. All rights reserved.
* Use is subject to license terms.
*/
#include <ctype.h>
#include <errno.h>
#include <fcntl.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <sys/fs/zfs.h>
#include <sys/ioctl.h>
#include <sys/stat.h>
#if defined(ZFS_ASAN_ENABLED)
/*
* zvol_id is invoked by udev with the help of ptrace()
* making sanitized binary with leak detection croak
* because of tracing mechanisms collision
*/
extern const char *__asan_default_options(void);
const char *__asan_default_options(void) {
return ("abort_on_error=true:halt_on_error=true:"
"allocator_may_return_null=true:disable_coredump=false:"
"detect_stack_use_after_return=true:detect_leaks=false");
}
#endif
int
main(int argc, const char *const *argv)
{
if (argc != 2 || strncmp(argv[1], "/dev/zd", 7) != 0) {
fprintf(stderr, "usage: %s /dev/zdX\n", argv[0]);
return (1);
}
const char *dev_name = argv[1];
size_t i, len;
int fd;
struct stat sb;
if ((fd = open(dev_name, O_RDONLY|O_CLOEXEC)) == -1 ||
fstat(fd, &sb) != 0) {
fprintf(stderr, "%s: %s\n", dev_name, strerror(errno));
return (1);
}
char zvol_name[MAXNAMELEN + strlen("-part") + 10];
if (ioctl(fd, BLKZNAME, zvol_name) == -1) {
fprintf(stderr, "%s: BLKZNAME: %s\n",
dev_name, strerror(errno));
return (1);
}
const char *dev_part = strrchr(dev_name, 'p');
len = strlen(zvol_name);
if (dev_part != NULL) {
sprintf(zvol_name + len, "-part%s", dev_part + 1);
len = strlen(zvol_name);
}
for (i = 0; i < len; ++i)
if (isblank(zvol_name[i]))
zvol_name[i] = '+';
puts(zvol_name);
return (0);
}