On Sat, 20 Feb 2010 00:28:18 +0200
"Kirill A. Shutemov" <kirill@xxxxxxxxxxxxx> wrote:
> Signed-off-by: Kirill A. Shutemov <kirill@xxxxxxxxxxxxx>
Nice. but please add one-line patch description, at least.
(Because it helps we see merge log rather than patch dump.)
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx>
> ---
> Documentation/cgroups/cgroup_event_listener.c | 102 +++++++++++++++++++++++++
> 1 files changed, 102 insertions(+), 0 deletions(-)
> create mode 100644 Documentation/cgroups/cgroup_event_listener.c
>
> diff --git a/Documentation/cgroups/cgroup_event_listener.c b/Documentation/cgroups/cgroup_event_listener.c
> new file mode 100644
> index 0000000..a8277b2
> --- /dev/null
> +++ b/Documentation/cgroups/cgroup_event_listener.c
> @@ -0,0 +1,102 @@
> +/*
> + * cgroup_event_listener.c - Simple listener of cgroup events
> + *
> + * Copyright (C) Kirill A. Shutemov <kirill@xxxxxxxxxxxxx>
> + */
> +
> +#include <assert.h>
> +#include <errno.h>
> +#include <fcntl.h>
> +#include <libgen.h>
> +#include <limits.h>
> +#include <stdio.h>
> +#include <string.h>
> +#include <unistd.h>
> +
> +#include <sys/eventfd.h>
> +
> +#define USAGE_STR "Usage: cgroup_event_listener <path-to-control-file> <args>\n"
> +
> +int main(int argc, char **argv)
> +{
> + int efd = -1;
> + int cfd = -1;
> + int event_control = -1;
> + char event_control_path[PATH_MAX];
> + int ret;
> +
> + if (argc != 3) {
> + fputs(USAGE_STR, stderr);
> + return 1;
> + }
> +
> + cfd = open(argv[1], O_RDONLY);
> + if (cfd == -1) {
> + fprintf(stderr, "Cannot open %s: %s\n", argv[1],
> + strerror(errno));
> + goto out;
> + }
> +
> + 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;
> + }
> +
> + 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;
> + }
> +
> + efd = eventfd(0, 0);
> + if (efd == -1) {
> + perror("eventfd() failed");
> + goto out;
> + }
> +
> + ret = dprintf(event_control, "%d %d %s", efd, cfd, argv[2]);
> + if (ret == -1) {
> + perror("Cannot write to cgroup.event_control");
> + goto out;
> + }
> +
> + while (1) {
> + uint64_t result;
> +
> + ret = read(efd, &result, sizeof(result));
> + if (ret == -1) {
> + if (errno == EINTR)
> + continue;
> + perror("Cannot read from eventfd");
> + break;
> + }
> + 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 accessable any more");
> + break;
> + }
> +
> + 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);
> +}
> --
> 1.6.6.2
>
>
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