static void do_child(void)
{
int fd, offset;
char buf[FS_BLOCKSIZE];
char *addr = NULL;
/*
* We have changed SIGBUS' handler in parent process by calling
* tst_sig(FORK, DEF_HANDLER, NULL), so here just restore it.
*/
if (signal(SIGBUS, SIG_DFL) == SIG_ERR)
tst_brkm(TBROK | TERRNO, NULL, "signal(SIGBUS) failed");
memset(buf, 'a', FS_BLOCKSIZE);
fd = SAFE_OPEN(NULL, "testfilec", O_RDWR);
SAFE_PWRITE(NULL, 1, fd, buf, FS_BLOCKSIZE, 0);
/*
* In case mremap() may fail because that memory area can not be
* expanded at current virtual address(MREMAP_MAYMOVE is not set),
* we first do a mmap(page_size * 2) operation to reserve some
* free address space.
*/
addr = SAFE_MMAP(NULL, NULL, page_size * 2, PROT_WRITE | PROT_READ,
MAP_PRIVATE_EXCEPT_UCLINUX | MAP_ANONYMOUS, -1, 0);
SAFE_MUNMAP(NULL, addr, page_size * 2);
addr = SAFE_MMAP(NULL, addr, FS_BLOCKSIZE, PROT_WRITE | PROT_READ,
MAP_SHARED, fd, 0);
addr[0] = 'a';
SAFE_FTRUNCATE(NULL, fd, page_size * 2);
addr = mremap(addr, FS_BLOCKSIZE, 2 * page_size, 0);
if (addr == MAP_FAILED)
tst_brkm(TBROK | TERRNO, NULL, "mremap failed unexpectedly");
/*
* Let parent process consume FS free blocks as many as possible, then
* there'll be no free blocks allocated for this new file mmaping for
* offset starting at 1024, 2048, or 3072. If this above kernel bug
* has been fixed, usually child process will killed by SIGBUS signal,
* if not, the data 'A', 'B', 'C' will be silently discarded later when
* kernel writepage is called, that means data corruption.
*/
TST_SAFE_CHECKPOINT_WAKE(NULL, 0);
TST_SAFE_CHECKPOINT_WAIT(NULL, 0);
for (offset = FS_BLOCKSIZE; offset < page_size; offset += FS_BLOCKSIZE)
addr[offset] = 'a';
SAFE_MUNMAP(NULL, addr, 2 * page_size);
SAFE_CLOSE(NULL, fd);
exit(TFAIL);
}
static void verify_pwritev2(unsigned int n)
{
int i;
char preadbuf[CHUNK];
struct tcase *tc = &tcases[n];
SAFE_PWRITE(1, fd, initbuf, sizeof(initbuf), 0);
SAFE_LSEEK(fd, tc->seek_off, SEEK_SET);
TEST(pwritev2(fd, wr_iovec, tc->count, tc->write_off, 0));
if (TST_RET < 0) {
tst_res(TFAIL | TTERRNO, "pwritev2() failed");
return;
}
if (TST_RET != tc->size) {
tst_res(TFAIL, "pwritev2() wrote %li bytes, expected %zi",
TST_RET, tc->size);
return;
}
if (SAFE_LSEEK(fd, 0, SEEK_CUR) != tc->exp_off) {
tst_res(TFAIL, "pwritev2() had changed file offset");
return;
}
memset(preadbuf, 0, CHUNK);
if (tc->write_off != -1)
SAFE_PREAD(1, fd, preadbuf, tc->size, tc->write_off);
else
SAFE_PREAD(1, fd, preadbuf, tc->size, tc->seek_off);
for (i = 0; i < tc->size; i++) {
if (preadbuf[i] != 0x61)
break;
}
if (i != tc->size) {
tst_res(TFAIL, "buffer wrong at %i have %c expected 'a'",
i, preadbuf[i]);
return;
}
tst_res(TPASS, "pwritev2() wrote %zi bytes successfully "
"with content 'a' expectedly ", tc->size);
}
