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/* ISC license. */
#include <skalibs/sysdeps.h>
#if defined(SKALIBS_HASPOSIXSPAWN) && defined(SKALIBS_HASPOSIXSPAWNEARLYRETURN)
#include <errno.h>
#include <signal.h>
#include <sys/wait.h>
#include <skalibs/allreadwrite.h>
#include <skalibs/djbunix.h>
#include "child_spawn-internal.h"
pid_t child_spawn_workaround (pid_t pid, int const *p)
{
siginfo_t si ;
int e ;
ssize_t r ;
char c ;
fd_close(p[1]) ;
r = fd_read(p[0], &c, 1) ;
fd_close(p[0]) ;
if (r == -1) return 0 ;
if (r) return (errno = EILSEQ, 0) ; /* child wrote, wtf */
do e = waitid(P_PID, pid, &si, WEXITED | WNOHANG | WNOWAIT) ;
while (e == -1 && errno == EINTR) ;
if (e == -1) return pid ; /* we're in trouble, but don't leak a child */
if (!si.si_pid) return pid ; /* child is running */
if (si.si_code != CLD_EXITED || si.si_status != 127) return pid ; /* child died after execve(), let caller handle it */
/*
child exited 127, so either execve() failed, which is what we want to catch,
or it raced like a mofo, execve()d and then exited 127 on its own, in which
case, tough luck, it never existed.
*/
wait_pid(pid, 0) ;
return (errno = 0, 0) ;
}
#else
/* avoid empty TUs */
extern int skalibs_child_spawn_workaround_dummy_ ;
#endif
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