diff options
author | André Fabian Silva Delgado <emulatorman@parabola.nu> | 2015-08-05 17:04:01 -0300 |
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committer | André Fabian Silva Delgado <emulatorman@parabola.nu> | 2015-08-05 17:04:01 -0300 |
commit | 57f0f512b273f60d52568b8c6b77e17f5636edc0 (patch) | |
tree | 5e910f0e82173f4ef4f51111366a3f1299037a7b /tools/cgroup/cgroup_event_listener.c |
Initial import
Diffstat (limited to 'tools/cgroup/cgroup_event_listener.c')
-rw-r--r-- | tools/cgroup/cgroup_event_listener.c | 82 |
1 files changed, 82 insertions, 0 deletions
diff --git a/tools/cgroup/cgroup_event_listener.c b/tools/cgroup/cgroup_event_listener.c new file mode 100644 index 000000000..4eb550720 --- /dev/null +++ b/tools/cgroup/cgroup_event_listener.c @@ -0,0 +1,82 @@ +/* + * cgroup_event_listener.c - Simple listener of cgroup events + * + * Copyright (C) Kirill A. Shutemov <kirill@shutemov.name> + */ + +#include <assert.h> +#include <err.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>" + +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) + errx(1, "%s", USAGE_STR); + + cfd = open(argv[1], O_RDONLY); + 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) + errx(1, "Path to cgroup.event_control is too long"); + + event_control = open(event_control_path, O_WRONLY); + if (event_control == -1) + err(1, "Cannot open %s", event_control_path); + + efd = eventfd(0, 0); + if (efd == -1) + err(1, "eventfd() failed"); + + ret = snprintf(line, LINE_MAX, "%d %d %s", efd, cfd, argv[2]); + if (ret >= LINE_MAX) + errx(1, "Arguments string is too long"); + + ret = write(event_control, line, strlen(line) + 1); + if (ret == -1) + err(1, "Cannot write to cgroup.event_control"); + + while (1) { + uint64_t result; + + ret = read(efd, &result, sizeof(result)); + if (ret == -1) { + if (errno == EINTR) + continue; + 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."); + break; + } + + if (ret == -1) + err(1, "cgroup.event_control is not accessible any more"); + + printf("%s %s: crossed\n", argv[1], argv[2]); + } + + return 0; +} |