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author | David S. Miller <davem@davemloft.net> | 2010-03-15 23:23:54 (GMT) |
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committer | David S. Miller <davem@davemloft.net> | 2010-03-15 23:23:54 (GMT) |
commit | 4961e02f1999e1c3468c09b2669c94d7c3ae82a8 (patch) | |
tree | 44c15abb09d7ba5e17a9aba95ee246648b1c1a8a /Documentation/cgroups/cgroup_event_listener.c | |
parent | d14a0ebda7d3daede1a99c01527affb9ceaa4c22 (diff) | |
parent | a3d3203e4bb40f253b1541e310dc0f9305be7c84 (diff) | |
download | linux-fsl-qoriq-4961e02f1999e1c3468c09b2669c94d7c3ae82a8.tar.xz |
Merge branch 'master' of /home/davem/src/GIT/linux-2.6/
Diffstat (limited to 'Documentation/cgroups/cgroup_event_listener.c')
-rw-r--r-- | Documentation/cgroups/cgroup_event_listener.c | 110 |
1 files changed, 110 insertions, 0 deletions
diff --git a/Documentation/cgroups/cgroup_event_listener.c b/Documentation/cgroups/cgroup_event_listener.c new file mode 100644 index 0000000..8c2bfc4 --- /dev/null +++ b/Documentation/cgroups/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 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); +} |