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/* 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 = 0 ;
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') ;
pid_t mypid ;
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(&mypid, 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 ;
pid = mypid ;
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 (;;)
{
int 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)
{
while (!pid)
{
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("read an 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 = l.arg ; 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) ;
if (ndelay_on(0) < 0) strerr_diefu1sys(111, "set stdin nonblocking") ;
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 ;
if (buffer_len(buffer_0))
handle_stdin(&sa, linevar, argv, envp) ;
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 (cont && !pid && x[1].revents & IOPAUSE_READ)
handle_stdin(&sa, linevar, argv, envp) ;
}
}
if (verbosity >= 2) strerr_warni1x("exiting") ;
return 0 ;
}
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