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https://github.com/Zenithsiz/ftmemsim-valgrind.git
synced 2026-02-09 05:10:23 +00:00
f05d0d0969
Bug caused by the following problem: for each mmap, Valgrind reads the 1st 1024 bytes to detect if this is an mmap-ed file containing debug info to decode. Reading this 1Kb is done with VG_(pread). VG_(pread) should be the equivalent of syscall pread but on linux, it is implemented as a seek+read. The patch implements VG_(pread) in terms of the underlying pread syscall. Test mmap_fcntl_bug.c completed to also verify the fd current position before and after the mmap. tested on linux x86/amd64/ppc32/ppc64/s390. (not tested on Darwin) (manually tested on arm-android) git-svn-id: svn://svn.valgrind.org/valgrind/trunk@12504
79 lines
2.0 KiB
C
79 lines
2.0 KiB
C
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/* Test program to demonstrate valgrind breaking fcntl locks during
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* mmap. Feed it a r/w file, such as its own source code. */
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/* See bug 280965. */
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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 <sys/mman.h>
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#include <sys/types.h>
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#include <sys/wait.h>
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#include <err.h>
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int main(int argc, char *argv[])
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{
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struct flock fl;
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const char *file = /* argv[1]; */
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"mmap_fcntl_bug.c";
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int fd, status;
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off_t initial;
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if (!file)
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errx(1, "Usage: %s <normal-file>", argv[0]);
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fd = open(file, O_RDWR);
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if (fd < 0)
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err(1, "Opening %s", file);
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// reproduce bug 297991: mmap interferes with fd position
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initial = lseek(fd, 123, SEEK_SET);
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if (123 != initial)
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err(1, "initial off_t differs from 123 (TEST FAILED)");
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if (lseek(fd, 0, SEEK_CUR) != 123)
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err(1, "zero offset from initial differs from 123 (TEST FAILED)");
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fl.l_type = F_WRLCK;
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fl.l_whence = SEEK_SET;
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fl.l_start = 0;
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fl.l_len = 1;
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/* I'm assuming noone else tries to lock this! */
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if (fcntl(fd, F_SETLK, &fl) != 0)
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err(1, "Locking %s", file);
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/* If under valgrind, mmap re-opens and closes file, screwing us */
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if (mmap(NULL, getpagesize(), PROT_READ|PROT_WRITE, MAP_PRIVATE, fd, 0) == MAP_FAILED)
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err(1, "mmap of %s", file);
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if (lseek(fd, 0, SEEK_CUR) != 123)
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errx(1, "zero offset from initial after mmap differs from 123 (TEST FAILED)");
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switch (fork()) {
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case 0:
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/* Child. Lock should fail. */
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if (fcntl(fd, F_SETLK, &fl) == 0)
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exit(1);
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exit(0);
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case -1:
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err(1, "Fork failed");
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}
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if (wait(&status) == -1)
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err(1, "Child vanished?");
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if (!WIFEXITED(status))
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errx(1, "Child died with signal %i", WTERMSIG(status));
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switch (WEXITSTATUS(status)) {
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case 1:
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errx(1, "Child got lock, we must have dropped it (TEST FAILED)");
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case 0:
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fprintf(stderr, "Child exited with zero (TEST PASSED).\n");
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return 0;
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default:
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errx(1, "Child weird exit status %i", WEXITSTATUS(status));
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}
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}
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