From 50a00de6e4aa6337b17a179019ec7689a2cc6b6d Mon Sep 17 00:00:00 2001 From: Laurent Bercot Date: Fri, 15 Jun 2018 12:36:00 +0000 Subject: Down signal customization: add ./down-signal file and s6-svc -r --- NEWS | 4 ++++ doc/s6-svc.html | 14 +++++++++++--- doc/servicedir.html | 32 ++++++++++++++++-------------- doc/upgrade.html | 6 ++++++ src/supervision/s6-supervise.c | 44 ++++++++++++++++++++++++++++++------------ src/supervision/s6-svc.c | 5 +++-- 6 files changed, 74 insertions(+), 31 deletions(-) diff --git a/NEWS b/NEWS index 1996769..c96a861 100644 --- a/NEWS +++ b/NEWS @@ -8,6 +8,10 @@ In 2.7.2.0 *shallow readiness*, i.e. readiness will be reported when s6-svscan is ready to receive s6-svscanctl commands; it does *not* mean all the services started at s6-svscan launch will be ready. + - New optional file in a service directory: down-signal. It allows you to +customize the signal sent by s6-svc -d (and now s6-svc -r too). + - New s6-svc option: -r. Sends the signal defined in the down-signal file +(still SIGTERM by default). In 2.7.1.1 diff --git a/doc/s6-svc.html b/doc/s6-svc.html index 22a4f68..c1e617f 100644 --- a/doc/s6-svc.html +++ b/doc/s6-svc.html @@ -28,7 +28,7 @@ knowing their PIDs, and without using horrible hacks such as .pid files.

Interface 

-     s6-svc [ -wu | -wU | -wd | -wD | -wr | -wR ] [ -T timeout ] [ -abqhkti12pcyoduxO ] servicedir
+     s6-svc [ -wu | -wU | -wd | -wD | -wr | -wR ] [ -T timeout ] [ -abqhkti12pcyoduxOr ] servicedir

@@ -55,7 +55,10 @@ a command, or 100 if no s6-supervise process is running on servicedir.

  • -y : send a SIGWINCH to the supervised process
  • -o : once. Equivalent to "-uO".
  • -d : down. If the supervised process is up, send it -a SIGTERM and a SIGCONT. Do not restart it.
    • +a SIGTERM (by default) then a SIGCONT (to make sure even stopped processes +receive the signal aimed to kill them) and do not restart it. +The SIGTERM default can be changed by editing the ./down-signal +file in the service directory.
  • -u : up. If the supervised process is down, start it. Automatically restart it when it dies.
  • -x : exit. When the service is asked to be down and @@ -71,6 +74,11 @@ stdin, stdout and stderr redirected to /dev/null.
  • -O : mark the service to run once at most. iow: do not restart the supervised process when it dies. If it is down when the command is received, do not even start it.
    • +
  • -r : If the service is up, restart it, by sending it a +signal to kill it and letting s6-supervise +start it again. By default, the signal is a SIGTERM; this can be configured +via the ./down-signal file in the service +directory.
  • -T timeout : if the -wstate option has been given, -T specifies a timeout (in milliseconds) after which s6-svc will exit 1 with an error message if @@ -106,7 +114,7 @@ service directory. Traditionally, this makes web servers reload their configuration file.

    -
     s6-svc -t /service/sshd
    +
     s6-svc -r /service/sshd

    Kill (and automatically restart, if the wanted state of the service is up) the process represented by the /service/sshd service directory - diff --git a/doc/servicedir.html b/doc/servicedir.html index 29236e7..2e6a937 100644 --- a/doc/servicedir.html +++ b/doc/servicedir.html @@ -40,7 +40,7 @@ for historical and compatibility reasons.) A service directory foo may contain the following elements:

    -
  • An optional executable file named finish. Like run, +
    • +
  • An optional executable file named finish. Like run, it can be any executable file. This finish script, if present, is executed everytime the run script dies. Generally, its main purpose is to clean up non-volatile data such as the filesystem after the supervised process has been killed. If the foo service is supposed to be up, -foo/run is restarted -after foo/finish dies. +foo/run is restarted after foo/finish dies.
    • -
  • A directory named supervise. It is automatically created by +
  • A directory named supervise. It is automatically created by s6-supervise if it does not exist. This is where s6-supervise stores its information. The directory must be writable.
    • -
  • An optional, empty, regular file named down. If such a file exists, +
  • An optional, empty, regular file named down. If such a file exists, the default state of the service is considered down, not up: s6-supervise will not automatically start it until it receives a s6-svc -u command. If no down file exists, the default state of the service is up.
    • -
  • An optional, empty, regular file named nosetsid. If such a file exists, +
  • An optional, empty, regular file named nosetsid. If such a file exists, s6-supervise will not make the service a process group and session leader; the service will be run in the same process group as s6-supervise. If no nosetsid file exists, the service has its own process group and is started as a session leader.
    • -
  • An optional regular file named notification-fd. If such a file +
  • An optional regular file named notification-fd. If such a file exists, it means that the service supports readiness notification. The file must only contain an unsigned integer, which is the number of the file descriptor that @@ -128,7 +127,7 @@ notification from the service and broadcast readiness, i.e. any s6-svlisten1 -U or s6-svlisten -U processes will be triggered.
    • -
  • An optional regular file named timeout-kill. If such a file +
  • An optional regular file named timeout-kill. If such a file exists, it must only contain an unsigned integer t. If t is nonzero, then on receipt of a s6-svc -d command, which sends a SIGTERM and a SIGCONT to the service, a timeout of t @@ -137,25 +136,30 @@ milliseconds, then it is sent a SIGKILL. If timeout-kill does not exist, or contains 0 or an invalid value, then the service is never forcibly killed (unless, of course, a s6-svc -k command is sent).
    • -
  • An optional regular file named timeout-finish. If such a file +
  • An optional regular file named timeout-finish. If such a file exists, it must only contain an unsigned integer, which is the number of milliseconds after which the ./finish script, if it exists, will be killed with a SIGKILL. The default is 5000: finish scripts are killed if they're still alive after 5 seconds. A value of 0 allows finish scripts to run forever.
    • -
  • An optional regular file named max-death-tally. If such a file +
  • An optional regular file named max-death-tally. If such a file exists, it must only contain an unsigned integer, which is the maximum number of service death events that s6-supervise will keep track of. If the service dies more than this number of times, the oldest events will be forgotten. Tracking death events is useful, for instance, when throttling service restarts. The value cannot be greater than 4096. If the file does not exist, a default of 100 is used.
    • -
  • A fifodir named event. It is automatically +
  • An optional regular file named down-signal. If such a file +exists, it must only contain the name or number of a signal, followed by a +newline. This signal will be used to kill the supervised process when a +s6-svc -d or s6-svc -r +command is used. If the file does not exist, SIGTERM will be used by default.
    • +
  • A fifodir named event. It is automatically created by s6-supervise if it does not exist. foo/event is the rendez-vous point for listeners, where s6-supervise will send notifications when the service goes up or down.
    • -
  • An optional service directory named log. If it exists and foo +
  • An optional service directory named log. If it exists and foo is in a scandir, and s6-svscan runs on that scandir, then two services are monitored: foo and foo/log. A pipe is open and maintained between foo and diff --git a/doc/upgrade.html b/doc/upgrade.html index 4ea789c..428e41f 100644 --- a/doc/upgrade.html +++ b/doc/upgrade.html @@ -25,6 +25,12 @@ s6-ipcserver-socketbinder.
  • -d notif option added to s6-svscan.
    • +
  • New optional ./down-signal file in a +service directory, to tell +s6-supervise to use another signal than +SIGTERM when bringing the service down.
    • +
  • New -r option added to s6-svc, to +restart the service via the signal defined in ./down-signal.

    • in 2.7.1.1

    diff --git a/src/supervision/s6-supervise.c b/src/supervision/s6-supervise.c index 9d821bd..bdc4730 100644 --- a/src/supervision/s6-supervise.c +++ b/src/supervision/s6-supervise.c @@ -30,7 +30,7 @@ typedef enum trans_e trans_t, *trans_t_ref ; enum trans_e { V_TIMEOUT, V_CHLD, V_TERM, V_HUP, V_QUIT, - V_a, V_b, V_q, V_h, V_k, V_t, V_i, V_1, V_2, V_f, V_F, V_p, V_c, V_y, + V_a, V_b, V_q, V_h, V_k, V_t, V_i, V_1, V_2, V_f, V_F, V_p, V_c, V_y, V_r, V_o, V_d, V_u, V_x, V_O, V_X } ; @@ -71,16 +71,22 @@ static inline void announce (void) strerr_warnwu1sys("write status file") ; } -static int read_uint (char const *file, unsigned int *fd) +static int read_file (char const *file, char *buf, size_t n) { - char buf[UINT_FMT + 1] ; - ssize_t r = openreadnclose_nb(file, buf, UINT_FMT) ; + ssize_t r = openreadnclose_nb(file, buf, n) ; if (r < 0) { if (errno != ENOENT) strerr_warnwu2sys("open ", file) ; return 0 ; } buf[byte_chr(buf, r, '\n')] = 0 ; + return 1 ; +} + +static int read_uint (char const *file, unsigned int *fd) +{ + char buf[UINT_FMT + 1] ; + if (!read_file(file, buf, UINT_FMT)) return 0 ; if (!uint0_scan(buf, fd)) { strerr_warnw2x("invalid ", file) ; @@ -89,6 +95,15 @@ static int read_uint (char const *file, unsigned int *fd) return 1 ; } +static inline int read_downsig (void) +{ + int sig = SIGTERM ; + char buf[16] ; + if (read_file("down-signal", buf, 15) && !sig0_scan(buf, &sig)) + strerr_warnw1x("invalid down-signal") ; + return sig ; +} + static void set_down_and_ready (char const *s, unsigned int n) { status.pid = 0 ; @@ -188,6 +203,11 @@ static void killy (void) kill(status.pid, SIGWINCH) ; } +static void killr (void) +{ + kill(status.pid, read_downsig()) ; +} + static void failcoe (int fd) { int e = errno ; @@ -430,7 +450,7 @@ static void up_d (void) tain_t tto ; unsigned int timeout ; status.flagwantup = 0 ; - killt() ; + killr() ; killc() ; if (!read_uint("timeout-kill", &timeout)) timeout = 0 ; if (timeout && tain_from_millisecs(&tto, timeout)) @@ -505,22 +525,22 @@ static void lastfinish_z (void) bail() ; } -static action_t_ref const actions[5][25] = +static action_t_ref const actions[5][26] = { { &downtimeout, &nop, &bail, &bail, &bail, - &nop, &nop, &nop, &nop, &nop, &nop, &nop, &nop, &nop, &nop, &nop, &nop, &nop, &nop, + &nop, &nop, &nop, &nop, &nop, &nop, &nop, &nop, &nop, &nop, &nop, &nop, &nop, &nop, &nop, &down_o, &down_d, &down_u, &bail, &down_O, &bail }, { &uptimeout, &up_z, &up_term, &up_x, &up_X, - &killa, &killb, &killq, &killh, &killk, &killt, &killi, &kill1, &kill2, &nop, &nop, &killp, &killc, &killy, + &killa, &killb, &killq, &killh, &killk, &killt, &killi, &kill1, &kill2, &nop, &nop, &killp, &killc, &killy, &killr, &up_o, &up_d, &up_u, &up_x, &up_o, &up_X }, { &finishtimeout, &finish_z, &finish_x, &finish_x, &finish_X, - &nop, &nop, &nop, &nop, &nop, &nop, &nop, &nop, &nop, &nop, &nop, &nop, &nop, &nop, + &nop, &nop, &nop, &nop, &nop, &nop, &nop, &nop, &nop, &nop, &nop, &nop, &nop, &nop, &nop, &up_o, &down_d, &finish_u, &finish_x, &up_o, &finish_X }, { &uptimeout, &lastup_z, &up_d, &nop, &closethem, - &killa, &killb, &killq, &killh, &killk, &killt, &killi, &kill1, &kill2, &nop, &nop, &killp, &killc, &killy, + &killa, &killb, &killq, &killh, &killk, &killt, &killi, &kill1, &kill2, &nop, &nop, &killp, &killc, &killy, &killr, &up_o, &up_d, &nop, &nop, &up_o, &closethem }, { &finishtimeout, &lastfinish_z, &nop, &nop, &closethem, - &nop, &nop, &nop, &nop, &nop, &nop, &nop, &nop, &nop, &nop, &nop, &nop, &nop, &nop, + &nop, &nop, &nop, &nop, &nop, &nop, &nop, &nop, &nop, &nop, &nop, &nop, &nop, &nop, &nop, &nop, &nop, &nop, &nop, &nop, &closethem } } ; @@ -600,7 +620,7 @@ static inline void handle_control (int fd) else if (!r) break ; else { - size_t pos = byte_chr("abqhkti12fFpcyoduxOX", 20, c) ; + size_t pos = byte_chr("abqhkti12fFpcyroduxOX", 20, c) ; if (pos < 20) (*actions[state][V_a + pos])() ; } } diff --git a/src/supervision/s6-svc.c b/src/supervision/s6-svc.c index d844b20..2166551 100644 --- a/src/supervision/s6-svc.c +++ b/src/supervision/s6-svc.c @@ -10,7 +10,7 @@ #include #include -#define USAGE "s6-svc [ -wu | -wU | -wd | -wD | -wr | -wR ] [ -T timeout ] [ -abqhkti12pcoduxOX ] servicedir" +#define USAGE "s6-svc [ -wu | -wU | -wd | -wD | -wr | -wR ] [ -T timeout ] [ -abqhkti12pcyroduxOX ] servicedir" #define dieusage() strerr_dieusage(100, USAGE) #define DATASIZE 63 @@ -41,13 +41,14 @@ int main (int argc, char const *const *argv, char const *const *envp) case '2' : case 'p' : case 'c' : + case 'y' : + case 'r' : case 'o' : case 'd' : case 'u' : case 'x' : case 'O' : case 'X' : - case 'y' : { if (datalen >= DATASIZE) strerr_dief1x(100, "too many commands") ; data[datalen++] = opt ; -- cgit v1.2.3