summaryrefslogtreecommitdiff
path: root/src/minutils/s6-uevent-spawner.c
diff options
context:
space:
mode:
Diffstat (limited to 'src/minutils/s6-uevent-spawner.c')
-rw-r--r--src/minutils/s6-uevent-spawner.c234
1 files changed, 234 insertions, 0 deletions
diff --git a/src/minutils/s6-uevent-spawner.c b/src/minutils/s6-uevent-spawner.c
new file mode 100644
index 0000000..b074f1f
--- /dev/null
+++ b/src/minutils/s6-uevent-spawner.c
@@ -0,0 +1,234 @@
+/* ISC license. */
+
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <spawn.h>
+#include <signal.h>
+#include <errno.h>
+#include <stdlib.h>
+#include <skalibs/config.h>
+#include <skalibs/allreadwrite.h>
+#include <skalibs/buffer.h>
+#include <skalibs/bytestr.h>
+#include <skalibs/uint.h>
+#include <skalibs/sgetopt.h>
+#include <skalibs/strerr2.h>
+#include <skalibs/tai.h>
+#include <skalibs/iopause.h>
+#include <skalibs/env.h>
+#include <skalibs/stralloc.h>
+#include <skalibs/djbunix.h>
+#include <skalibs/sig.h>
+#include <skalibs/selfpipe.h>
+#include <skalibs/skamisc.h>
+
+#define USAGE "s6-uevent-spawner [ -v verbosity ] [ -l linevar ] [ -t maxlife:maxterm:maxkill ] helperprogram..."
+#define dieusage() strerr_dieusage(100, USAGE)
+#define dienomem() strerr_diefu1sys(111, "build string") ;
+
+static unsigned int cont = 1, state = 0, verbosity = 1 ;
+static pid_t pid ;
+static tain_t lifetto = TAIN_INFINITE_RELATIVE,
+ termtto = TAIN_INFINITE_RELATIVE,
+ killtto = TAIN_INFINITE_RELATIVE,
+ deadline ;
+
+static inline void on_death (void)
+{
+ pid = 0 ;
+ state = 0 ;
+ tain_add_g(&deadline, &tain_infinite_relative) ;
+}
+
+static inline void on_event (char const *const *argv, char const *const *envp, char const *s, unsigned int len)
+{
+ posix_spawnattr_t attr ;
+ posix_spawn_file_actions_t actions ;
+ unsigned int envlen = env_len(envp) ;
+ unsigned int n = envlen + 1 + byte_count(s, len, '\0') ;
+ int e ;
+ char const *v[n] ;
+ if (!env_merge(v, n, envp, envlen, s, len))
+ strerr_diefu1sys(111, "env_merge") ;
+
+ e = posix_spawnattr_init(&attr) ;
+ if (e) { errno = e ; strerr_diefu1sys(111, "posix_spawnattr_init") ; }
+ {
+ sigset_t set ;
+ sigemptyset(&set) ;
+ e = posix_spawnattr_setsigmask(&attr, &set) ;
+ if (e) { errno = e ; strerr_diefu1sys(111, "posix_spawnattr_setsigmask") ; }
+ sigfillset(&set) ;
+ e = posix_spawnattr_setsigdefault(&attr, &set) ;
+ if (e) { errno = e ; strerr_diefu1sys(111, "posix_spawnattr_setsigdefault") ; }
+ }
+ e = posix_spawn_file_actions_init(&actions) ;
+ if (e) { errno = e ; strerr_diefu1sys(111, "posix_spawn_file_actions_init") ; }
+ e = posix_spawn_file_actions_addopen(&actions, 0, "/dev/null", O_RDONLY, S_IRUSR) ;
+ if (e) { errno = e ; strerr_diefu1sys(111, "posix_spawn_file_actions_addopen") ; }
+ e = posix_spawnp(&pid, argv[0], &actions, &attr, (char *const *)argv, (char * const *)v) ;
+ if (e) { errno = e ; strerr_diefu2sys(111, "spawn ", argv[0]) ; }
+ posix_spawn_file_actions_destroy(&actions) ;
+ posix_spawnattr_destroy(&attr) ;
+ state = 1 ;
+ tain_add_g(&deadline, &lifetto) ;
+}
+
+static inline void handle_timeout (void)
+{
+ switch (state)
+ {
+ case 0 :
+ tain_add_g(&deadline, &tain_infinite_relative) ;
+ break ;
+ case 1 :
+ kill(pid, SIGTERM) ;
+ tain_add_g(&deadline, &termtto) ;
+ state++ ;
+ break ;
+ case 2 :
+ kill(pid, SIGKILL) ;
+ tain_add_g(&deadline, &killtto) ;
+ state++ ;
+ break ;
+ case 3 :
+ strerr_dief1x(99, "child resisted SIGKILL - check your kernel logs.") ;
+ default :
+ strerr_dief1x(101, "internal error: inconsistent state. Please submit a bug-report.") ;
+ }
+}
+
+static inline void handle_signals (void)
+{
+ for (;;)
+ {
+ char c = selfpipe_read() ;
+ switch (c)
+ {
+ case -1 : strerr_diefu1sys(111, "selfpipe_read") ;
+ case 0 : return ;
+ case SIGCHLD :
+ if (!pid) wait_reap() ;
+ else
+ {
+ int wstat ;
+ int r = wait_pid_nohang(pid, &wstat) ;
+ if (r < 0)
+ if (errno != ECHILD) strerr_diefu1sys(111, "wait_pid_nohang") ;
+ else break ;
+ else if (!r) break ;
+ on_death() ;
+ }
+ break ;
+ default :
+ strerr_dief1x(101, "internal error: inconsistent signal handling. Please submit a bug-report.") ;
+ }
+ }
+}
+
+static inline void handle_stdin (stralloc *sa, char const *linevar, char const *const *argv, char const *const *envp)
+{
+ for (;;)
+ {
+ unsigned int start ;
+ register int r ;
+ if (!sa->len && linevar)
+ if (!stralloc_cats(sa, linevar) || !stralloc_catb(sa, "=", 1))
+ dienomem() ;
+ start = sa->len ;
+ r = sanitize_read(skagetln(buffer_0, sa, 0)) ;
+ if (r < 0)
+ {
+ cont = 0 ;
+ if (errno != EPIPE && verbosity) strerr_warnwu1sys("read from stdin") ;
+ }
+ if (r <= 0) break ;
+ if (sa->len == start + 1)
+ {
+ start = linevar ? 0 : str_len(sa->s) + 1 ;
+ if (start >= sa->len)
+ {
+ if (verbosity) strerr_warnw1x("empty event!") ;
+ }
+ else on_event(argv, envp, sa->s + start, sa->len - 1 - start) ;
+ sa->len = 0 ;
+ }
+ }
+}
+
+static inline int make_ttos (char const *s)
+{
+ unsigned int tlife = 0, tterm = 0, tkill = 0, pos = 0 ;
+ pos += uint_scan(s + pos, &tlife) ;
+ if (s[pos] && s[pos++] != ':') return 0 ;
+ if (!tlife) return 1 ;
+ tain_from_millisecs(&lifetto, tlife) ;
+ pos += uint_scan(s + pos, &tterm) ;
+ if (s[pos] && s[pos++] != ':') return 0 ;
+ if (!tterm) return 1 ;
+ tain_from_millisecs(&termtto, tterm) ;
+ tain_add(&termtto, &termtto, &lifetto) ;
+ pos += uint_scan(s + pos, &tkill) ;
+ if (s[pos]) return 0 ;
+ if (!tkill) return 1 ;
+ tain_from_millisecs(&killtto, tkill) ;
+ tain_add(&killtto, &killtto, &termtto) ;
+ return 1 ;
+}
+
+int main (int argc, char const *const *argv, char const *const *envp)
+{
+ iopause_fd x[2] = { { .events = IOPAUSE_READ }, { .fd = 0, .events = IOPAUSE_READ } } ;
+ char const *linevar = 0 ;
+ stralloc sa = STRALLOC_ZERO ;
+ PROG = "s6-uevent-spawner" ;
+ {
+ subgetopt_t l = SUBGETOPT_ZERO ;
+ for (;;)
+ {
+ register int opt = subgetopt_r(argc, argv, "l:v:t:", &l) ;
+ if (opt == -1) break ;
+ switch (opt)
+ {
+ case 'l' : linevar = optarg ; break ;
+ case 'v' : if (!uint0_scan(l.arg, &verbosity)) dieusage() ; break ;
+ case 't' : if (!make_ttos(l.arg)) dieusage() ; break ;
+ default : dieusage() ;
+ }
+ }
+ argc -= l.ind ; argv += l.ind ;
+ if (!argc) strerr_dieusage(100, USAGE) ;
+ }
+ if (linevar && linevar[str_chr(linevar, '=')])
+ strerr_dief2x(100, "invalid variable: ", linevar) ;
+
+ x[0].fd = selfpipe_init() ;
+ if (x[0].fd == -1) strerr_diefu1sys(111, "init selfpipe") ;
+ if (sig_ignore(SIGPIPE) < 0) strerr_diefu1sys(111, "ignore SIGPIPE") ;
+ if (selfpipe_trap(SIGCHLD) < 0) strerr_diefu1sys(111, "trap SIGCHLD") ;
+ if (setenv("PATH", SKALIBS_DEFAULTPATH, 0) < 0)
+ strerr_diefu1sys(111, "setenv PATH") ;
+
+ tain_now_g() ;
+ tain_add_g(&deadline, &tain_infinite_relative) ;
+ if (verbosity >= 2) strerr_warni1x("starting") ;
+
+ while (cont || pid)
+ {
+ register int r = iopause_g(x, 1 + (!pid && cont), &deadline) ;
+ if (r < 0) strerr_diefu1sys(111, "iopause") ;
+ else if (!r) handle_timeout() ;
+ else
+ {
+ if (x[0].revents & IOPAUSE_EXCEPT)
+ strerr_diefu1x(111, "iopause: trouble with selfpipe") ;
+ if (x[0].revents & IOPAUSE_READ) handle_signals() ;
+ else if (!pid && cont && (x[1].revents & IOPAUSE_READ))
+ handle_stdin(&sa, linevar, argv, envp) ;
+ }
+ }
+ if (verbosity >= 2) strerr_warni1x("exiting") ;
+ return 0 ;
+}
generated by cgit v1.2.3 (git 2.25.1) at 2024-09-20 03:46:05 +0000