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/* ISC license. */
#include <unistd.h>
#include <errno.h>
#include <signal.h>
#include <skalibs/allreadwrite.h>
#include <skalibs/sgetopt.h>
#include <skalibs/strerr2.h>
#include <skalibs/types.h>
#include <skalibs/tai.h>
#include <skalibs/iopause.h>
#include <skalibs/djbunix.h>
#include <skalibs/exec.h>
#include <s6/config.h>
#define USAGE "s6-setlock [ -r | -w ] [ -n | -N | -t timeout ] lockfile prog..."
#define dieusage() strerr_dieusage(100, USAGE)
int main (int argc, char const *const *argv)
{
unsigned int nb = 0, ex = 1 ;
unsigned int timeout = 0 ;
PROG = "s6-setlock" ;
for (;;)
{
int opt = subgetopt(argc, argv, "nNrwt:") ;
if (opt == -1) break ;
switch (opt)
{
case 'n' : nb = 1 ; break ;
case 'N' : nb = 0 ; break ;
case 'r' : ex = 0 ; break ;
case 'w' : ex = 1 ; break ;
case 't' : if (!uint0_scan(subgetopt_here.arg, &timeout)) dieusage() ; nb = 2 ; break ;
default : dieusage() ;
}
}
argc -= subgetopt_here.ind ; argv += subgetopt_here.ind ;
if (argc < 2) dieusage() ;
if (nb < 2)
{
int r, fd ;
if (ex)
{
fd = open_create(argv[0]) ;
if (fd < 0) strerr_diefu3sys(111, "open ", argv[0], " for writing") ;
}
else
{
fd = open_read(argv[0]) ;
if (fd < 0)
{
if (errno != ENOENT) strerr_diefu3sys(111, "open ", argv[0], " for reading") ;
fd = open_create(argv[0]) ;
if (fd < 0) strerr_diefu2sys(111, "create ", argv[0]) ;
close(fd) ;
fd = open_read(argv[0]) ;
if (fd < 0) strerr_diefu3sys(111, "open ", argv[0], " for reading") ;
}
}
r = fd_lock(fd, ex, nb) ;
if (!r) errno = EBUSY ;
if (r < 1) strerr_diefu2sys(1, "lock ", argv[0]) ;
}
else
{
char const *cargv[4] = { "s6lockd-helper", ex ? "w" : "r", argv[0], 0 } ;
char const *nullenv = { 0 } ;
iopause_fd x = { .events = IOPAUSE_READ } ;
tain_t deadline ;
int p[2] = { 0, 1 } ;
pid_t pid ;
char c ;
tain_now_set_stopwatch_g() ;
tain_from_millisecs(&deadline, timeout) ;
tain_add_g(&deadline, &deadline) ;
pid = child_spawn2(S6_LIBEXECPREFIX "s6lockd-helper", cargv, &nullenv, p) ;
if (!pid) strerr_diefu2sys(111, "spawn ", S6_LIBEXECPREFIX "s6lockd-helper") ;
x.fd = p[0] ;
for (;;)
{
ssize_t rr ;
int r = iopause_g(&x, 1, &deadline) ;
if (r < 0) strerr_diefu1sys(111, "iopause") ;
if (!r)
{
kill(pid, SIGTERM) ;
errno = ETIMEDOUT ;
strerr_diefu1sys(1, "acquire lock") ;
}
rr = sanitize_read(fd_read(p[0], &c, 1)) ;
if (rr < 0) strerr_diefu1sys(111, "read ack from helper") ;
if (rr) break ;
}
if (c != '!') strerr_dief1x(111, "helper sent garbage ack") ;
fd_close(p[0]) ;
if (uncoe(p[1]) < 0) strerr_diefu1sys(111, "uncoe fd to helper") ;
}
xexec(argv+1) ;
}
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