diff options
Diffstat (limited to 'src/minutils/s6-uevent-spawner.c')
| -rw-r--r-- | src/minutils/s6-uevent-spawner.c | 234 |
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 ; +} |