diff options
| -rw-r--r-- | tools/perf/Documentation/perf-daemon.txt | 3 | ||||
| -rw-r--r-- | tools/perf/builtin-daemon.c | 75 |
2 files changed, 77 insertions, 1 deletions
diff --git a/tools/perf/Documentation/perf-daemon.txt b/tools/perf/Documentation/perf-daemon.txt index 94d5e09a1e17..3c9e265858b2 100644 --- a/tools/perf/Documentation/perf-daemon.txt +++ b/tools/perf/Documentation/perf-daemon.txt @@ -49,7 +49,8 @@ OPTIONS --base=<PATH>:: Base directory path. Each daemon instance is running on top - of base directory. + of base directory. Only one instance of server can run on + top of one directory at the time. All generic options are available also under commands. diff --git a/tools/perf/builtin-daemon.c b/tools/perf/builtin-daemon.c index 324ce43e8ab1..2890573540f7 100644 --- a/tools/perf/builtin-daemon.c +++ b/tools/perf/builtin-daemon.c @@ -2,11 +2,13 @@ #include <internal/lib.h> #include <subcmd/parse-options.h> #include <api/fd/array.h> +#include <api/fs/fs.h> #include <linux/zalloc.h> #include <linux/string.h> #include <linux/limits.h> #include <linux/string.h> #include <string.h> +#include <sys/file.h> #include <signal.h> #include <stdlib.h> #include <time.h> @@ -570,12 +572,18 @@ static int cmd_session_list(struct daemon *daemon, union cmd *cmd, FILE *out) /* output */ csv_sep, daemon->base, SESSION_OUTPUT); + fprintf(out, "%c%s/%s", + /* lock */ + csv_sep, daemon->base, "lock"); + fprintf(out, "\n"); } else { fprintf(out, "[%d:daemon] base: %s\n", getpid(), daemon->base); if (cmd->list.verbose) { fprintf(out, " output: %s/%s\n", daemon->base, SESSION_OUTPUT); + fprintf(out, " lock: %s/lock\n", + daemon->base); } } @@ -906,6 +914,67 @@ static int setup_config(struct daemon *daemon) return daemon->config_real ? 0 : -1; } +#ifndef F_TLOCK +#define F_TLOCK 2 + +#include <sys/file.h> + +static int lockf(int fd, int cmd, off_t len) +{ + if (cmd != F_TLOCK || len != 0) + return -1; + + return flock(fd, LOCK_EX | LOCK_NB); +} +#endif // F_TLOCK + +/* + * Each daemon tries to create and lock BASE/lock file, + * if it's successful we are sure we're the only daemon + * running over the BASE. + * + * Once daemon is finished, file descriptor to lock file + * is closed and lock is released. + */ +static int check_lock(struct daemon *daemon) +{ + char path[PATH_MAX]; + char buf[20]; + int fd, pid; + ssize_t len; + + scnprintf(path, sizeof(path), "%s/lock", daemon->base); + + fd = open(path, O_RDWR|O_CREAT|O_CLOEXEC, 0640); + if (fd < 0) + return -1; + + if (lockf(fd, F_TLOCK, 0) < 0) { + filename__read_int(path, &pid); + fprintf(stderr, "failed: another perf daemon (pid %d) owns %s\n", + pid, daemon->base); + close(fd); + return -1; + } + + scnprintf(buf, sizeof(buf), "%d", getpid()); + len = strlen(buf); + + if (write(fd, buf, len) != len) { + perror("failed: write"); + close(fd); + return -1; + } + + if (ftruncate(fd, len)) { + perror("failed: ftruncate"); + close(fd); + return -1; + } + + return 0; +} + static int go_background(struct daemon *daemon) { int pid, fd; @@ -920,6 +989,9 @@ static int go_background(struct daemon *daemon) if (setsid() < 0) return -1; + if (check_lock(daemon)) + return -1; + umask(0); if (chdir(daemon->base)) { @@ -995,6 +1067,9 @@ static int __cmd_start(struct daemon *daemon, struct option parent_options[], if (setup_server_config(daemon)) return -1; + if (foreground && check_lock(daemon)) + return -1; + if (!foreground) { err = go_background(daemon); if (err) { |