diff options
author | Greg Thelen <gthelen@google.com> | 2013-01-05 01:05:17 +0400 |
---|---|---|
committer | Tejun Heo <tj@kernel.org> | 2013-01-07 21:41:28 +0400 |
commit | 92e015b1cfc24e3cb072385f25171b8599cc7ef3 (patch) | |
tree | 465c64f5b337dcdec22adb6cb4aa82c5fe410bca /tools/cgroup | |
parent | 12a9d2fef1d35770d3cdc2cd1faabb83c45bc0fa (diff) |
cgroups: move cgroup_event_listener.c to tools/cgroup
Move the cgroup_event_listener.c tool from Documentation into the new
tools/cgroup directory.
This change involves wiring cgroup_event_listener.c into the tools/
make system so that is can be built with:
$ make tools/cgroup
Signed-off-by: Greg Thelen <gthelen@google.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Diffstat (limited to 'tools/cgroup')
-rw-r--r-- | tools/cgroup/.gitignore | 1 | ||||
-rw-r--r-- | tools/cgroup/Makefile | 11 | ||||
-rw-r--r-- | tools/cgroup/cgroup_event_listener.c | 110 |
3 files changed, 122 insertions, 0 deletions
diff --git a/tools/cgroup/.gitignore b/tools/cgroup/.gitignore new file mode 100644 index 000000000000..633cd9b874f9 --- /dev/null +++ b/tools/cgroup/.gitignore @@ -0,0 +1 @@ +cgroup_event_listener diff --git a/tools/cgroup/Makefile b/tools/cgroup/Makefile new file mode 100644 index 000000000000..b4286196b763 --- /dev/null +++ b/tools/cgroup/Makefile @@ -0,0 +1,11 @@ +# Makefile for cgroup tools + +CC = $(CROSS_COMPILE)gcc +CFLAGS = -Wall -Wextra + +all: cgroup_event_listener +%: %.c + $(CC) $(CFLAGS) -o $@ $^ + +clean: + $(RM) cgroup_event_listener diff --git a/tools/cgroup/cgroup_event_listener.c b/tools/cgroup/cgroup_event_listener.c new file mode 100644 index 000000000000..3e082f96dc12 --- /dev/null +++ b/tools/cgroup/cgroup_event_listener.c @@ -0,0 +1,110 @@ +/* + * cgroup_event_listener.c - Simple listener of cgroup events + * + * Copyright (C) Kirill A. Shutemov <kirill@shutemov.name> + */ + +#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]; + char line[LINE_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 = 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; + } + + ret = write(event_control, line, strlen(line) + 1); + 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 accessible 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); +} |