Hi!
> +static int timed_read_kmsg(int fd, int timeout_sec)
> +{
> + int child, status, ret = 0;
> + int pipefd[2];
> + char msg[MAX_MSGSIZE];
> +
> + if (pipe(pipefd) != 0)
> + tst_brkm(TBROK|TERRNO, cleanup, "pipe failed");
> +
> + child = fork();
> + switch (child) {
> + case -1:
> + tst_brkm(TBROK|TERRNO, cleanup, "failed to fork");
> + case 0:
> + /* child does all the reading and keeps writing to
> + * pipe to let parent know that it didn't block */
> + SAFE_CLOSE(NULL, pipefd[0]);
There is a problem with calling the SAFE_ macros from child processes.
The SAFE_ macros use tst_brkm() interface to halt program execution (in
case of failure) which is not supposed to be used from child and may
lead to unexpected results.
> +static void test_seek(void)
> +{
> + int k, j = NUM_READ_RETRY, fd;
> + char msg[MAX_MSGSIZE];
> + unsigned long seqno[2];
> +
> + /* 1. read() after SEEK_SET 0 returns same (first) message */
> + tst_resm(TINFO, "TEST: seek SEEK_SET 0");
> +
> + fd = open("/dev/kmsg", O_RDONLY | O_NONBLOCK);
> + if (fd < 0)
> + tst_brkm(TBROK|TERRNO, cleanup, "failed to open /dev/kmsg");
> +
> + while (j) {
> + for (k = 0; k < 2; k++) {
> + TEST(read(fd, msg, sizeof(msg)));
> + if (TEST_RETURN == -1) {
> + if (errno == EPIPE)
> + break;
> + else
> + tst_brkm(TBROK|TTERRNO, cleanup,
> + "failed to read /dev/kmsg");
> + }
> + if (get_msg_fields(msg, NULL, &seqno[k]) != 0)
> + tst_resm(TFAIL, "failed to parse seqid: %s",
> + msg);
> + if (k == 0)
> + if (lseek(fd, 0, SEEK_SET) == -1)
> + tst_resm(TFAIL|TERRNO,
> + "SEEK_SET 0 failed");
> + }
> +
> + if (TEST_RETURN != -1)
> + break;
> +
> + /* give a second to whoever overwrote first message to finish */
> + sleep(1);
> + j--;
> +
> + /* read returned EPIPE, reopen fd and try again */
> + SAFE_CLOSE(cleanup, fd);
> + fd = open("/dev/kmsg", O_RDONLY | O_NONBLOCK);
> + if (fd < 0)
> + tst_brkm(TBROK|TERRNO, cleanup,
> + "failed to open /dev/kmsg");
I guess that the comment says something different than the code, there
is no read involved here.
Acked with change from SAFE_CLOSE() to close() in the child process.
--
Cyril Hrubis
[email protected]
------------------------------------------------------------------------------
This SF.net email is sponsored by Windows:
Build for Windows Store.
http://p.sf.net/sfu/windows-dev2dev
_______________________________________________
Ltp-list mailing list
[email protected]
https://lists.sourceforge.net/lists/listinfo/ltp-list
