[LTP] [PATCH v1] Rewrite process_vm_writev02.c using new LTP API
Cyril Hrubis
chrubis@suse.cz
Wed Feb 9 13:25:58 CET 2022
Hi!
> +/* \
^
Here as well.
> + * [Description]
> *
> - * This program is free software; you can redistribute it and/or modify
> - * it under the terms of the GNU General Public License as published by
> - * the Free Software Foundation; either version 2 of the License, or
> - * (at your option) any later version.
> - *
> - * This program is distributed in the hope that it will be useful,
> - * but WITHOUT ANY WARRANTY; without even the implied warranty of
> - * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
> - * the GNU General Public License for more details.
> - *
> - * You should have received a copy of the GNU General Public License
> - * along with this program; if not, write to the Free Software
> - * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
> + * Fork two children, the first one allocates a chunk of memory and the
> + * other one call process_vm_writev to write known data into the first
> + * child. Then first child verifies that the data is as expected.
> */
>
> -#define _GNU_SOURCE
> +#include <stdlib.h>
> #include <sys/types.h>
> #include <sys/uio.h>
> -#include <sys/wait.h>
> -#include <errno.h>
> -#include <stdio.h>
> -#include <stdlib.h>
> -#include <string.h>
> -#include <unistd.h>
> -#include <limits.h>
> -
> -#include "test.h"
> -#include "safe_macros.h"
> +#include "tst_test.h"
> #include "lapi/syscalls.h"
>
> -char *TCID = "process_vm_writev02";
> -int TST_TOTAL = 1;
> -
> -#define PADDING_SIZE 10
> -#define DEFAULT_CHAR 53
> +static uintptr_t *data_ptr;
> +static char *str_buffsize;
> +static int bufsize = 100000;
>
> -static int sflag;
> -static char *sz_opt;
> -static option_t options[] = {
> - {"s:", &sflag, &sz_opt},
> - {NULL, NULL, NULL}
> -};
> +static void child_alloc_and_verify(int buffsize)
> +{
> + char foo[buffsize];
> + int i;
> + int err;
>
> -static long bufsz;
> -static int pipe_fd[2];
> -static pid_t pids[2];
> + tst_res(TINFO, "child 0: allocate memory");
>
> -static void child_init_and_verify(void);
> -static void child_write(void);
> -static void setup(void);
> -static void cleanup(void);
> -static void help(void);
> + memset(foo, 'a', buffsize);
> + *data_ptr = (uintptr_t)foo;
>
> -int main(int argc, char **argv)
> -{
> - int lc, status;
> -
> - tst_parse_opts(argc, argv, options, &help);
> -
> - setup();
> - for (lc = 0; TEST_LOOPING(lc); lc++) {
> - tst_count = 0;
> -
> - SAFE_PIPE(cleanup, pipe_fd);
> -
> - /* the start of child_init_and_verify and child_write is
> - * already synchronized via pipe */
> - pids[0] = fork();
> - switch (pids[0]) {
> - case -1:
> - tst_brkm(TBROK | TERRNO, cleanup, "fork #0");
> - case 0:
> - child_init_and_verify();
> - exit(0);
> - default:
> - break;
> - }
> -
> - pids[1] = fork();
> - switch (pids[1]) {
> - case -1:
> - tst_brkm(TBROK | TERRNO, cleanup, "fork #1");
> - case 0:
> - child_write();
> - exit(0);
> - }
> -
> - /* wait until child_write writes into
> - * child_init_and_verify's VM */
> - SAFE_WAITPID(cleanup, pids[1], &status, 0);
> - if (!WIFEXITED(status) || WEXITSTATUS(status) != 0)
> - tst_resm(TFAIL, "child 1 returns %d", status);
> -
> - /* signal child_init_and_verify to verify its VM now */
> - TST_SAFE_CHECKPOINT_WAKE(cleanup, 0);
> -
> - SAFE_WAITPID(cleanup, pids[0], &status, 0);
> - if (!WIFEXITED(status) || WEXITSTATUS(status) != 0)
> - tst_resm(TFAIL, "child 0 returns %d", status);
> - }
> + TST_CHECKPOINT_WAKE_AND_WAIT(0);
>
> - cleanup();
> - tst_exit();
> -}
> + err = 0;
> + for (i = 0; i < buffsize; i++)
> + if (foo[i] != 'w')
> + err++;
>
> -static void child_init_and_verify(void)
> -{
> - unsigned char *foo;
> - char buf[bufsz];
> - long i, nr_err;
> -
> - foo = SAFE_MALLOC(tst_exit, bufsz);
> - for (i = 0; i < bufsz; i++)
> - foo[i] = DEFAULT_CHAR;
> - tst_resm(TINFO, "child 0: memory allocated.");
> -
> - /* passing addr of string "foo" via pipe */
> - SAFE_CLOSE(tst_exit, pipe_fd[0]);
> - snprintf(buf, bufsz, "%p", foo);
> - SAFE_WRITE(tst_exit, 1, pipe_fd[1], buf, strlen(buf) + 1);
> - SAFE_CLOSE(tst_exit, pipe_fd[1]);
> -
> - /* wait until child_write() is done writing to our VM */
> - TST_SAFE_CHECKPOINT_WAIT(cleanup, 0);
> -
> - nr_err = 0;
> - for (i = 0; i < bufsz; i++) {
> - if (foo[i] != i % 256) {
> -#if DEBUG
> - tst_resm(TFAIL, "child 0: expected %i, got %i for "
> - "byte seq %ld", i % 256, foo[i], i);
> -#endif
> - nr_err++;
> - }
> - }
> - if (nr_err)
> - tst_brkm(TFAIL, tst_exit, "child 0: got %ld incorrect bytes.",
> - nr_err);
> + if (err)
> + tst_res(TFAIL, "child 0: found %d differences from expected data", err);
> else
> - tst_resm(TPASS, "child 0: all bytes are expected.");
> + tst_res(TPASS, "child 0: read back expected data");
> }
>
> -static void child_write(void)
> +static void child_write(int buffsize, pid_t pid_alloc)
> {
> - unsigned char *lp, *rp;
> - char buf[bufsz];
> + char lp[buffsize];
> struct iovec local, remote;
> - long i;
> -
> - /* get addr from pipe */
> - SAFE_CLOSE(tst_exit, pipe_fd[1]);
> - SAFE_READ(tst_exit, 0, pipe_fd[0], buf, bufsz);
> - SAFE_CLOSE(tst_exit, pipe_fd[0]);
> - if (sscanf(buf, "%p", &rp) != 1)
> - tst_brkm(TBROK | TERRNO, tst_exit, "sscanf");
> -
> - lp = SAFE_MALLOC(tst_exit, bufsz + PADDING_SIZE * 2);
> -
> - for (i = 0; i < bufsz + PADDING_SIZE * 2; i++)
> - lp[i] = DEFAULT_CHAR;
> - for (i = 0; i < bufsz; i++)
> - lp[i + PADDING_SIZE] = i % 256;
> -
> - local.iov_base = lp + PADDING_SIZE;
> - local.iov_len = bufsz;
> - remote.iov_base = rp;
> - remote.iov_len = bufsz;
> -
> - tst_resm(TINFO, "child 2: write to the same memory location.");
> - TEST(tst_syscall(__NR_process_vm_writev, pids[0], &local,
> - 1UL, &remote, 1UL, 0UL));
> - if (TEST_RETURN != bufsz)
> - tst_brkm(TFAIL | TTERRNO, tst_exit, "process_vm_readv");
> +
> + tst_res(TINFO, "child 1: write to the same memory location");
> +
> + memset(lp, 'w', buffsize);
> +
> + local.iov_base = lp;
> + local.iov_len = buffsize;
> + remote.iov_base = (void *)*data_ptr;
> + remote.iov_len = buffsize;
> +
> + TEST(tst_syscall(__NR_process_vm_writev, pid_alloc, &local, 1UL, &remote,
> + 1UL, 0UL));
> +
> + if (TST_RET < 0)
> + tst_brk(TBROK, "process_vm_writev: %s", tst_strerrno(-TST_RET));
The tst_syscall() calls libc syscall() which does it's magic and stores
the error into the errno. So this should really just juse TBROK |
TTERRNO flags instead of the tst_strerrno() with invalid value.
Also this could be converted into TST_EXP_POSSITIVE_SILENT() call
followed by a check if the TST_RET mathces bufsize and doing pass/fail
based on that.
> + if (TST_RET != buffsize)
> + tst_brk(TBROK, "process_vm_writev: expected %d bytes but got %ld",
> + buffsize, TST_RET);
> }
>
> static void setup(void)
> {
> - tst_require_root();
> -
> /* Just a sanity check of the existence of syscall */
> tst_syscall(__NR_process_vm_writev, getpid(), NULL, 0UL, NULL, 0UL, 0UL);
>
> - bufsz =
> - sflag ? SAFE_STRTOL(NULL, sz_opt, 1, LONG_MAX - PADDING_SIZE * 2)
> - : 100000;
> + if (tst_parse_int(str_buffsize, &bufsize, 1, INT_MAX))
> + tst_brk(TBROK, "Invalid buffer size '%s'", str_buffsize);
>
> - tst_tmpdir();
> - TST_CHECKPOINT_INIT(cleanup);
> -
> - TEST_PAUSE;
> + data_ptr = SAFE_MMAP(NULL, sizeof(uintptr_t), PROT_READ | PROT_WRITE,
> + MAP_SHARED | MAP_ANONYMOUS, -1, 0);
> }
>
> static void cleanup(void)
> {
> - tst_rmdir();
> + if (data_ptr)
> + SAFE_MUNMAP(data_ptr, sizeof(uintptr_t));
> }
>
> -static void help(void)
> +static void run(void)
> {
> - printf(" -s NUM Set the size of total buffer size.\n");
> + pid_t pid_alloc;
> + pid_t pid_write;
> + int status;
> +
> + pid_alloc = SAFE_FORK();
> + if (!pid_alloc) {
> + child_alloc_and_verify(bufsize);
> + return;
> + }
> +
> + /* wait until child_alloc_and_verify has allocated VM */
I do not think that these comments add too much value, I would have just
removed them. It's pretty clear which chekpoint we are waiting for here.
> + TST_CHECKPOINT_WAIT(0);
> +
> + pid_write = SAFE_FORK();
> + if (!pid_write) {
> + child_write(bufsize, pid_alloc);
> + return;
> + }
> +
> + /* wait until pid_write reads from child_alloc_and_verify's VM */
And for which children we are waiting here.
> + SAFE_WAITPID(pid_write, &status, 0);
> + if (!WIFEXITED(status) || WEXITSTATUS(status) != 0)
> + tst_res(TFAIL, "child 1: returns %d", status);
Can we use the tst_strstatus() here instead of the raw number here? And
also this is more likely TBROK instead of TFAIL if the process segfaults
of something. So maybe:
tst_res(TBROK, "child write: %s", tst_strstatus(status));
> + /* child_alloc_and_verify is free to exit now */
And here.
> + TST_CHECKPOINT_WAKE(0);
> +
> + SAFE_WAITPID(pid_alloc, &status, 0);
> + if (!WIFEXITED(status) || WEXITSTATUS(status) != 0)
> + tst_res(TFAIL, "child 0: returns %d", status);
We don't have to wait for the second child, the library will coolect it
just fine.
> }
> +
> +static struct tst_test test = {
> + .test_all = run,
> + .setup = setup,
> + .cleanup = cleanup,
> + .forks_child = 1,
> + .needs_checkpoints = 1,
> + .options = (struct tst_option[]) {
> + {"s:", &str_buffsize, "Total buffer size (default 100000)"},
> + {},
> + },
> +};
> --
> 2.34.1
>
>
> --
> Mailing list info: https://lists.linux.it/listinfo/ltp
--
Cyril Hrubis
chrubis@suse.cz
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