On Mon, Jun 09, 2014 at 07:37:53PM +0800, Eryu Guan wrote:
> getcwd(2) may return "/" instead of the correct cwd on buggy kernel.
What buggy kernel are we talking about here? In what conditions may
that bug happen?
> Regression test for:
> ede4ceb prepend_path() needs to reinitialize dentry/vfsmount/mnt on restarts
> f650080 __dentry_path() fixes
Al's commits don't tell you anything about the context of the bug
being fixed...
....
> diff --git a/src/t_getcwd.c b/src/t_getcwd.c
> new file mode 100644
> index 0000000..891de75
> --- /dev/null
> +++ b/src/t_getcwd.c
> @@ -0,0 +1,90 @@
> +#include <sys/types.h>
> +#include <sys/wait.h>
> +#include <errno.h>
> +#include <fcntl.h>
> +#include <signal.h>
> +#include <stdio.h>
> +#include <stdlib.h>
> +#include <string.h>
> +#include <unistd.h>
> +
> +#define TIMEOUT 60
Does it need to run for 60 seconds? If we keep adding tests that run
one timeouts measured in minutes, we're going to blow out the
runtime of the test suite to being unmanageable pretty quickly.
> +#define BUF_SIZE 256
> +
> +static sig_atomic_t end;
> +
> +void test_getcwd(char *init_cwd)
> +{
> + int i = 0;
> + char cur_cwd[BUF_SIZE];
> + while (!end) {
> + getcwd(cur_cwd, BUF_SIZE);
> + if (strncmp(init_cwd, cur_cwd, BUF_SIZE)) {
> + printf("[%u] %s != %s\n", i, init_cwd, cur_cwd);
> + break;
> + }
> + i++;
> + }
> +}
So this runs in a tight loop checking if it's working dir
changes? This should return an error if the $CWD changes...
> +void do_rename(char *prefix)
> +{
> + int i = 0;
> + int fd;
> + char c_name[BUF_SIZE];
> + char n_name[BUF_SIZE];
> +
> + strncpy(c_name, prefix, BUF_SIZE);
> +
> + fd = open(c_name, O_CREAT | O_RDWR);
> + if (fd < 0) {
> + fprintf(stderr, "failed to create file %s: %s\n",
> + c_name, strerror(errno));
> + exit(1);
> + }
> + close(fd);
> +
> + while (1) {
> + i++;
> + snprintf(n_name, BUF_SIZE, "%s%u", prefix, i);
> + rename(c_name, n_name);
> + strncpy(c_name, n_name, BUF_SIZE);
> + }
> +}
And the child process sits in a tight loop renaming a file in $CWD
until it is killed?
> +void sigproc(int sig)
> +{
> + end = 1;
> +}
> +
> +int main(int argc, char *argv[])
> +{
> + char init_cwd[BUF_SIZE];
> + pid_t pid;
> + int status;
> + int ret = 1;
> +
> + getcwd(init_cwd, BUF_SIZE);
> +
> + if (signal(SIGALRM, sigproc) == SIG_ERR) {
> + perror("signal failed");
> + exit(1);
> + }
> +
> + alarm(TIMEOUT);
> +
> + pid = fork();
> + if (pid < 0) {
> + perror("fork failed");
> + exit(1);
> + } else if (pid == 0) {
> + do_rename("testfile");
> + } else {
> + test_getcwd(init_cwd);
> + ret = !end;
ret = test_getcwd(init_cwd);
> + kill(pid, SIGTERM);
> + waitpid(pid, &status, 0);
> + }
> +
> + exit(ret);
> +}
> diff --git a/tests/generic/028 b/tests/generic/028
> new file mode 100755
> index 0000000..12216df
> --- /dev/null
> +++ b/tests/generic/028
> @@ -0,0 +1,54 @@
> +#! /bin/bash
> +# FS QA Test No. generic/028
> +#
> +# Regression test for
> +# ede4ceb prepend_path() needs to reinitialize dentry/vfsmount/mnt on restarts
> +# f650080 __dentry_path() fixes
Needs a better description.
> +
> +rm -f $seqres.full
$seqres.full is not used by the test, so no need to remove it.
> --- a/tests/generic/group
> +++ b/tests/generic/group
> @@ -30,6 +30,7 @@
> 025 auto quick
> 026 acl quick auto
> 027 auto enospc
> +028 auto
If this test doesn't need to run for 60s, then it could also be a
quick test...
Cheers,
Dave.
--
Dave Chinner
david@xxxxxxxxxxxxx
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