diff options
author | Greg Thelen <gthelen@google.com> | 2013-01-07 11:50:17 -0800 |
---|---|---|
committer | Tejun Heo <tj@kernel.org> | 2013-01-08 10:00:44 -0800 |
commit | 799105d514384b80cbe3182dbcb4ed30aa07e1f5 (patch) | |
tree | a268f0a96609fb09408fb77fd5474489cbb63c76 | |
parent | 92e015b1cfc24e3cb072385f25171b8599cc7ef3 (diff) | |
download | talos-op-linux-799105d514384b80cbe3182dbcb4ed30aa07e1f5.tar.gz talos-op-linux-799105d514384b80cbe3182dbcb4ed30aa07e1f5.zip |
cgroups: fix cgroup_event_listener error handling
The error handling in cgroup_event_listener.c did not correctly deal
with either an error opening either <control_file> or
cgroup.event_control. Due to an uninitialized variable the program
exit code was undefined if either of these opens failed.
This patch simplifies and corrects cgroup_event_listener.c error
handling by:
1. using err*() rather than printf(),exit()
2. depending on process exit to close open files
With this patch failures always return non-zero error.
Signed-off-by: Greg Thelen <gthelen@google.com>
Acked-by: Li Zefan <lizefan@huawei.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
-rw-r--r-- | tools/cgroup/cgroup_event_listener.c | 72 |
1 files changed, 22 insertions, 50 deletions
diff --git a/tools/cgroup/cgroup_event_listener.c b/tools/cgroup/cgroup_event_listener.c index 3e082f96dc12..4eb5507205c9 100644 --- a/tools/cgroup/cgroup_event_listener.c +++ b/tools/cgroup/cgroup_event_listener.c @@ -5,6 +5,7 @@ */ #include <assert.h> +#include <err.h> #include <errno.h> #include <fcntl.h> #include <libgen.h> @@ -15,7 +16,7 @@ #include <sys/eventfd.h> -#define USAGE_STR "Usage: cgroup_event_listener <path-to-control-file> <args>\n" +#define USAGE_STR "Usage: cgroup_event_listener <path-to-control-file> <args>" int main(int argc, char **argv) { @@ -26,49 +27,33 @@ int main(int argc, char **argv) char line[LINE_MAX]; int ret; - if (argc != 3) { - fputs(USAGE_STR, stderr); - return 1; - } + if (argc != 3) + errx(1, "%s", USAGE_STR); cfd = open(argv[1], O_RDONLY); - if (cfd == -1) { - fprintf(stderr, "Cannot open %s: %s\n", argv[1], - strerror(errno)); - goto out; - } + if (cfd == -1) + err(1, "Cannot open %s", argv[1]); ret = snprintf(event_control_path, PATH_MAX, "%s/cgroup.event_control", dirname(argv[1])); - if (ret >= PATH_MAX) { - fputs("Path to cgroup.event_control is too long\n", stderr); - goto out; - } + if (ret >= PATH_MAX) + errx(1, "Path to cgroup.event_control is too long"); event_control = open(event_control_path, O_WRONLY); - if (event_control == -1) { - fprintf(stderr, "Cannot open %s: %s\n", event_control_path, - strerror(errno)); - goto out; - } + if (event_control == -1) + err(1, "Cannot open %s", event_control_path); efd = eventfd(0, 0); - if (efd == -1) { - perror("eventfd() failed"); - goto out; - } + if (efd == -1) + err(1, "eventfd() failed"); ret = snprintf(line, LINE_MAX, "%d %d %s", efd, cfd, argv[2]); - if (ret >= LINE_MAX) { - fputs("Arguments string is too long\n", stderr); - goto out; - } + if (ret >= LINE_MAX) + errx(1, "Arguments string is too long"); ret = write(event_control, line, strlen(line) + 1); - if (ret == -1) { - perror("Cannot write to cgroup.event_control"); - goto out; - } + if (ret == -1) + err(1, "Cannot write to cgroup.event_control"); while (1) { uint64_t result; @@ -77,34 +62,21 @@ int main(int argc, char **argv) if (ret == -1) { if (errno == EINTR) continue; - perror("Cannot read from eventfd"); - break; + err(1, "Cannot read from eventfd"); } assert(ret == sizeof(result)); ret = access(event_control_path, W_OK); if ((ret == -1) && (errno == ENOENT)) { - puts("The cgroup seems to have removed."); - ret = 0; - break; - } - - if (ret == -1) { - perror("cgroup.event_control " - "is not accessible any more"); + puts("The cgroup seems to have removed."); break; } + if (ret == -1) + err(1, "cgroup.event_control is not accessible any more"); + printf("%s %s: crossed\n", argv[1], argv[2]); } -out: - if (efd >= 0) - close(efd); - if (event_control >= 0) - close(event_control); - if (cfd >= 0) - close(cfd); - - return (ret != 0); + return 0; } |