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/* ISC license. */
#include <unistd.h>
#include <errno.h>
#include <skalibs/uint.h>
#include <skalibs/sgetopt.h>
#include <skalibs/strerr2.h>
#include <skalibs/allreadwrite.h>
#include <skalibs/tai.h>
#include <skalibs/iopause.h>
#include <skalibs/djbunix.h>
#include <s6/ftrigw.h>
#define USAGE "s6-notifywhenup [ -d fd ] [ -e fifodir ] [ -f ] [ -t timeout ] prog..."
#define dieusage() strerr_dieusage(100, USAGE)
static int run_child (int fd, char const *fifodir, unsigned int timeout)
{
char dummy[4096] ;
iopause_fd x = { .fd = fd, .events = IOPAUSE_READ } ;
tain_t deadline ;
int haswritten = 0 ;
register int r = 0 ;
if (!tain_now_g()) strerr_diefu1sys(111, "tain_now") ;
tain_from_millisecs(&deadline, timeout) ;
tain_add_g(&deadline, &deadline) ;
while (!r)
{
register int r = iopause_g(&x, 1, &deadline) ;
if (r < 0) strerr_diefu1sys(111, "iopause") ;
if (!r) return 99 ;
while (r > 0)
{
r = sanitize_read(fd_read(fd, dummy, 4096)) ;
if (r > 0) haswritten = 1 ;
}
}
if (errno != EPIPE) strerr_diefu1sys(111, "read from parent") ;
if (haswritten) ftrigw_notify(fifodir, 'U') ;
return 0 ;
}
int main (int argc, char const *const *argv, char const *const *envp)
{
unsigned int fd = 1 ;
char const *fifodir = "event" ;
int df = 1 ;
unsigned int timeout = 0 ;
PROG = "s6-notifywhenup" ;
{
subgetopt_t l = SUBGETOPT_ZERO ;
for (;;)
{
register int opt = subgetopt_r(argc, argv, "d:e:ft:", &l) ;
if (opt == -1) break ;
switch (opt)
{
case 'd' : if (!uint0_scan(l.arg, &fd)) dieusage() ; break ;
case 'e' : fifodir = l.arg ; break ;
case 'f' : df = 0 ; break ;
case 't' : if (!uint0_scan(l.arg, &timeout)) dieusage() ; break ;
default : dieusage() ;
}
}
argc -= l.ind ; argv += l.ind ;
}
if (!argc) dieusage() ;
{
int p[2] ;
pid_t pid ;
if (pipe(p) < 0) strerr_diefu1sys(111, "pipe") ;
pid = df ? doublefork() : fork() ;
if (pid < 0) strerr_diefu1sys(111, df ? "doublefork" : "fork") ;
else if (pid)
{
PROG = "s6-notifywhenup (child)" ;
fd_close(p[1]) ;
return run_child(p[0], fifodir, timeout) ;
}
fd_close(p[0]) ;
if (fd_move((int)fd, p[1]) < 0) strerr_diefu1sys(111, "fd_move") ;
}
pathexec_run(argv[0], argv, envp) ;
strerr_dieexec(111, argv[1]) ;
}
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