linux/tools/testing/selftests/proc/thread-self.c
Alexey Dobriyan 2cd36fb329 proc: test /proc/thread-self symlink
Same story: I have WIP patch to make it faster, so better have a test
as well.

Link: http://lkml.kernel.org/r/20180627195209.GC18113@avx2
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Shuah Khan <shuahkh@osg.samsung.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-08-22 10:52:45 -07:00

65 lines
1.7 KiB
C

/*
* Copyright © 2018 Alexey Dobriyan <adobriyan@gmail.com>
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
// Test that /proc/thread-self gives correct TGID/PID.
#undef NDEBUG
#include <assert.h>
#include <sched.h>
#include <stdio.h>
#include <unistd.h>
#include <sys/mman.h>
#include <sys/wait.h>
#include "proc.h"
int f(void *arg)
{
char buf1[64], buf2[64];
pid_t pid, tid;
ssize_t rv;
pid = sys_getpid();
tid = sys_gettid();
snprintf(buf1, sizeof(buf1), "%u/task/%u", pid, tid);
rv = readlink("/proc/thread-self", buf2, sizeof(buf2));
assert(rv == strlen(buf1));
buf2[rv] = '\0';
assert(streq(buf1, buf2));
if (arg)
exit(0);
return 0;
}
int main(void)
{
const int PAGE_SIZE = sysconf(_SC_PAGESIZE);
pid_t pid;
void *stack;
/* main thread */
f((void *)0);
stack = mmap(NULL, 2 * PAGE_SIZE, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0);
assert(stack != MAP_FAILED);
/* side thread */
pid = clone(f, stack + PAGE_SIZE, CLONE_THREAD|CLONE_SIGHAND|CLONE_VM, (void *)1);
assert(pid > 0);
pause();
return 0;
}