| |
| /* Test program to demonstrate valgrind breaking fcntl locks during |
| * mmap. Feed it a r/w file, such as its own source code. */ |
| |
| /* See bug 280965. */ |
| |
| #include <stdio.h> |
| #include <stdlib.h> |
| #include <unistd.h> |
| #include <fcntl.h> |
| #include <sys/mman.h> |
| #include <sys/types.h> |
| #include <sys/wait.h> |
| #include <err.h> |
| |
| int main(int argc, char *argv[]) |
| { |
| struct flock fl; |
| const char *file = /* argv[1]; */ |
| "mmap_fcntl_bug.c"; |
| int fd, status; |
| off_t initial; |
| |
| if (!file) |
| errx(1, "Usage: %s <normal-file>", argv[0]); |
| |
| fd = open(file, O_RDWR); |
| if (fd < 0) |
| err(1, "Opening %s", file); |
| |
| // reproduce bug 297991: mmap interferes with fd position |
| initial = lseek(fd, 123, SEEK_SET); |
| if (123 != initial) |
| err(1, "initial off_t differs from 123 (TEST FAILED)"); |
| if (lseek(fd, 0, SEEK_CUR) != 123) |
| err(1, "zero offset from initial differs from 123 (TEST FAILED)"); |
| |
| fl.l_type = F_WRLCK; |
| fl.l_whence = SEEK_SET; |
| fl.l_start = 0; |
| fl.l_len = 1; |
| |
| /* I'm assuming noone else tries to lock this! */ |
| if (fcntl(fd, F_SETLK, &fl) != 0) |
| err(1, "Locking %s", file); |
| |
| /* If under valgrind, mmap re-opens and closes file, screwing us */ |
| if (mmap(NULL, getpagesize(), PROT_READ|PROT_WRITE, MAP_PRIVATE, fd, 0) == MAP_FAILED) |
| err(1, "mmap of %s", file); |
| if (lseek(fd, 0, SEEK_CUR) != 123) |
| errx(1, "zero offset from initial after mmap differs from 123 (TEST FAILED)"); |
| |
| switch (fork()) { |
| case 0: |
| /* Child. Lock should fail. */ |
| if (fcntl(fd, F_SETLK, &fl) == 0) |
| exit(1); |
| exit(0); |
| case -1: |
| err(1, "Fork failed"); |
| } |
| |
| if (wait(&status) == -1) |
| err(1, "Child vanished?"); |
| |
| if (!WIFEXITED(status)) |
| errx(1, "Child died with signal %i", WTERMSIG(status)); |
| |
| switch (WEXITSTATUS(status)) { |
| case 1: |
| errx(1, "Child got lock, we must have dropped it (TEST FAILED)"); |
| case 0: |
| fprintf(stderr, "Child exited with zero (TEST PASSED).\n"); |
| return 0; |
| default: |
| errx(1, "Child weird exit status %i", WEXITSTATUS(status)); |
| } |
| } |