From 09812eb764b440651f3ff4cb5d37bd343f800560 Mon Sep 17 00:00:00 2001 From: Lennart Poettering Date: Sun, 22 Dec 2013 22:14:05 +0100 Subject: sd-daemon: introduce sd_watchdog_enabled() for parsing $WATCHDOG_USEC Also, introduce a new environment variable named $WATCHDOG_PID which cotnains the PID of the process that is supposed to send the keep-alive events. This is similar how $LISTEN_FDS and $LISTEN_PID work together, and protects against confusing processes further down the process tree due to inherited environment. --- src/core/execute.c | 18 ++++++-- src/core/execute.h | 1 + src/core/mount.c | 1 + src/core/service.c | 9 +--- src/core/socket.c | 1 + src/core/swap.c | 1 + src/libsystemd-bus/sd-event.c | 11 +---- src/libsystemd-daemon/libsystemd-daemon.sym | 5 +++ src/libsystemd-daemon/sd-daemon.c | 66 +++++++++++++++++++++++++++++ src/systemd/sd-daemon.h | 21 ++++++++- 10 files changed, 114 insertions(+), 20 deletions(-) (limited to 'src') diff --git a/src/core/execute.c b/src/core/execute.c index 4265717895..9b33ec0ec5 100644 --- a/src/core/execute.c +++ b/src/core/execute.c @@ -1020,6 +1020,7 @@ static void do_idle_pipe_dance(int idle_pipe[4]) { static int build_environment( ExecContext *c, unsigned n_fds, + usec_t watchdog_usec, const char *home, const char *username, const char *shell, @@ -1032,7 +1033,7 @@ static int build_environment( assert(c); assert(ret); - our_env = new(char*, 8); + our_env = new0(char*, 10); if (!our_env) return -ENOMEM; @@ -1046,6 +1047,16 @@ static int build_environment( our_env[n_env++] = x; } + if (watchdog_usec > 0) { + if (asprintf(&x, "WATCHDOG_PID=%lu", (unsigned long) getpid()) < 0) + return -ENOMEM; + our_env[n_env++] = x; + + if (asprintf(&x, "WATCHDOG_USEC=%llu", (unsigned long long) watchdog_usec) < 0) + return -ENOMEM; + our_env[n_env++] = x; + } + if (home) { x = strappend("HOME=", home); if (!x) @@ -1084,7 +1095,7 @@ static int build_environment( } our_env[n_env++] = NULL; - assert(n_env <= 8); + assert(n_env <= 10); *ret = our_env; our_env = NULL; @@ -1104,6 +1115,7 @@ int exec_spawn(ExecCommand *command, CGroupControllerMask cgroup_supported, const char *cgroup_path, const char *unit_id, + usec_t watchdog_usec, int idle_pipe[4], ExecRuntime *runtime, pid_t *ret) { @@ -1560,7 +1572,7 @@ int exec_spawn(ExecCommand *command, } } - err = build_environment(context, n_fds, home, username, shell, &our_env); + err = build_environment(context, n_fds, watchdog_usec, home, username, shell, &our_env); if (r < 0) { r = EXIT_MEMORY; goto fail_child; diff --git a/src/core/execute.h b/src/core/execute.h index bd3db0b633..989373f481 100644 --- a/src/core/execute.h +++ b/src/core/execute.h @@ -181,6 +181,7 @@ int exec_spawn(ExecCommand *command, CGroupControllerMask cgroup_mask, const char *cgroup_path, const char *unit_id, + usec_t watchdog_usec, int pipe_fd[2], ExecRuntime *runtime, pid_t *ret); diff --git a/src/core/mount.c b/src/core/mount.c index 2b7934e404..09efa1b6e0 100644 --- a/src/core/mount.c +++ b/src/core/mount.c @@ -787,6 +787,7 @@ static int mount_spawn(Mount *m, ExecCommand *c, pid_t *_pid) { UNIT(m)->manager->cgroup_supported, UNIT(m)->cgroup_path, UNIT(m)->id, + 0, NULL, m->exec_runtime, &pid); diff --git a/src/core/service.c b/src/core/service.c index 87eaa29378..4eb3d9e668 100644 --- a/src/core/service.c +++ b/src/core/service.c @@ -1750,7 +1750,7 @@ static int service_spawn( if (r < 0) goto fail; - our_env = new0(char*, 5); + our_env = new0(char*, 4); if (!our_env) { r = -ENOMEM; goto fail; @@ -1768,12 +1768,6 @@ static int service_spawn( goto fail; } - if (s->watchdog_usec > 0) - if (asprintf(our_env + n_env++, "WATCHDOG_USEC=%llu", (unsigned long long) s->watchdog_usec) < 0) { - r = -ENOMEM; - goto fail; - } - if (UNIT(s)->manager->running_as != SYSTEMD_SYSTEM) if (asprintf(our_env + n_env++, "MANAGERPID=%lu", (unsigned long) getpid()) < 0) { r = -ENOMEM; @@ -1804,6 +1798,7 @@ static int service_spawn( UNIT(s)->manager->cgroup_supported, path, UNIT(s)->id, + s->watchdog_usec, s->type == SERVICE_IDLE ? UNIT(s)->manager->idle_pipe : NULL, s->exec_runtime, &pid); diff --git a/src/core/socket.c b/src/core/socket.c index 2442221355..31fc2a2526 100644 --- a/src/core/socket.c +++ b/src/core/socket.c @@ -1254,6 +1254,7 @@ static int socket_spawn(Socket *s, ExecCommand *c, pid_t *_pid) { UNIT(s)->manager->cgroup_supported, UNIT(s)->cgroup_path, UNIT(s)->id, + 0, NULL, s->exec_runtime, &pid); diff --git a/src/core/swap.c b/src/core/swap.c index 79862e5b87..e0627db965 100644 --- a/src/core/swap.c +++ b/src/core/swap.c @@ -645,6 +645,7 @@ static int swap_spawn(Swap *s, ExecCommand *c, pid_t *_pid) { UNIT(s)->manager->cgroup_supported, UNIT(s)->cgroup_path, UNIT(s)->id, + 0, NULL, s->exec_runtime, &pid); diff --git a/src/libsystemd-bus/sd-event.c b/src/libsystemd-bus/sd-event.c index a1baac52aa..bfc798ca6e 100644 --- a/src/libsystemd-bus/sd-event.c +++ b/src/libsystemd-bus/sd-event.c @@ -2164,17 +2164,10 @@ _public_ int sd_event_set_watchdog(sd_event *e, int b) { if (b) { struct epoll_event ev = {}; - const char *env; - env = getenv("WATCHDOG_USEC"); - if (!env) - return false; - - r = safe_atou64(env, &e->watchdog_period); - if (r < 0) + r = sd_watchdog_enabled(false, &e->watchdog_period); + if (r <= 0) return r; - if (e->watchdog_period <= 0) - return -EIO; /* Issue first ping immediately */ sd_notify(false, "WATCHDOG=1"); diff --git a/src/libsystemd-daemon/libsystemd-daemon.sym b/src/libsystemd-daemon/libsystemd-daemon.sym index f440238931..aa9be51c6a 100644 --- a/src/libsystemd-daemon/libsystemd-daemon.sym +++ b/src/libsystemd-daemon/libsystemd-daemon.sym @@ -25,3 +25,8 @@ global: local: *; }; + +LIBSYSTEMD_DAEMON_209 { +global: + sd_watchdog_enabled; +} LIBSYSTEMD_DAEMON_31; diff --git a/src/libsystemd-daemon/sd-daemon.c b/src/libsystemd-daemon/sd-daemon.c index 485b301023..94230c9ed6 100644 --- a/src/libsystemd-daemon/sd-daemon.c +++ b/src/libsystemd-daemon/sd-daemon.c @@ -518,3 +518,69 @@ _sd_export_ int sd_booted(void) { return !!S_ISDIR(st.st_mode); #endif } + +_sd_export_ int sd_watchdog_enabled(int unset_environment, uint64_t *usec) { + +#if defined(DISABLE_SYSTEMD) || !defined(__linux__) + return 0; +#else + unsigned long long ll; + unsigned long l; + const char *e; + char *p = NULL; + int r; + + e = getenv("WATCHDOG_PID"); + if (!e) { + r = 0; + goto finish; + } + + errno = 0; + l = strtoul(e, &p, 10); + if (errno > 0) { + r = -errno; + goto finish; + } + if (!p || p == e || *p || l <= 0) { + r = -EINVAL; + goto finish; + } + + /* Is this for us? */ + if (getpid() != (pid_t) l) { + r = 0; + goto finish; + } + + e = getenv("WATCHDOG_USEC"); + if (!e) { + r = -EINVAL; + goto finish; + } + + errno = 0; + ll = strtoull(e, &p, 10); + if (errno > 0) { + r = -errno; + goto finish; + } + if (!p || p == e || *p || l <= 0) { + r = -EINVAL; + goto finish; + } + + if (usec) + *usec = ll; + + r = 1; + +finish: + if (unset_environment) { + unsetenv("WATCHDOG_PID"); + unsetenv("WATCHDOG_USEC"); + } + + return r; +#endif +} diff --git a/src/systemd/sd-daemon.h b/src/systemd/sd-daemon.h index daa3f4c857..43deb8cc7d 100644 --- a/src/systemd/sd-daemon.h +++ b/src/systemd/sd-daemon.h @@ -186,6 +186,8 @@ int sd_is_socket_unix(int fd, int type, int listening, const char *path, size_t the file descriptor is a POSIX Message Queue of the specified name, 0 otherwise. If path is NULL a message queue name check is not done. Returns a negative errno style error code on failure. + + See sd_is_mq(3) for more information. */ int sd_is_mq(int fd, const char *path); @@ -220,7 +222,8 @@ int sd_is_mq(int fd, const char *path); WATCHDOG=1 Tells systemd to update the watchdog timestamp. Services using this feature should do this in regular intervals. A watchdog framework can use the - timestamps to detect failed services. + timestamps to detect failed services. Also see + sd_watchdog_enabled() below. Daemons can choose to send additional variables. However, it is recommended to prefix variable names not listed above with X_. @@ -275,6 +278,22 @@ int sd_notifyf(int unset_environment, const char *format, ...) _sd_printf_attr_( */ int sd_booted(void); +/* + Returns > 0 if the service manager expects watchdog keep-alive + events to be sent regularly via sd_notify(0, "WATCHDOG=1"). Returns + 0 if it does not expect this. If the usec argument is non-NULL + returns the watchdog timeout in µs after which the service manager + will act on a process that has not sent a watchdog keep alive + message. This function is useful to implement services that + recognize automatically if they are being run under supervision of + systemd with WatchdogSec= set. It is recommended for clients to + generate keep-alive pings via sd_notify(0, "WATCHDOG=1") every half + of the returned time. + + See sd_watchdog_enabled(3) for more information. +*/ +int sd_watchdog_enabled(int unset_environment, uint64_t *usec); + #ifdef __cplusplus } #endif -- cgit v1.2.3-54-g00ecf