pid_t child_spawn1_internal (char const *prog, char const *const *argv, char const *const *envp, int *p, int to)
{
int e ;
int syncp[2] ;
pid_t pid ;
if (coe(p[0]) < 0 || pipecoe(syncp) < 0)
{
e = errno ;
fd_close(p[1]) ;
fd_close(p[0]) ;
errno = e ;
return 0 ;
}
pid = fork() ;
if (pid < 0)
{
e = errno ;
fd_close(syncp[1]) ;
fd_close(syncp[0]) ;
fd_close(p[1]) ;
fd_close(p[0]) ;
errno = e ;
return 0 ;
}
if (!pid)
{
fd_close(syncp[0]) ;
fd_close(p[!(to & 1)]) ;
if (fd_move(to & 1, p[to & 1]) < 0) goto err ;
if ((to & 2) && (fd_copy(!(to & 1), to & 1) < 0)) goto err ;
sig_blocknone() ;
pathexec_run(prog, argv, envp) ;
err:
e = errno ;
fd_write(syncp[1], (char *)&e, sizeof(e)) ;
_exit(127) ;
}
fd_close(syncp[1]) ;
fd_close(p[to & 1]) ;
syncp[1] = fd_read(syncp[0], (char *)&e, sizeof(e)) ;
if (syncp[1] < 0)
{
e = errno ;
fd_close(syncp[0]) ;
fd_close(p[!(to & 1)]) ;
errno = e ;
return 0 ;
}
fd_close(syncp[0]) ;
if (syncp[1] == sizeof(e))
{
fd_close(p[!(to & 1)]) ;
wait_pid(pid, &syncp[1]) ;
errno = e ;
return 0 ;
}
return pid ;
}
unsigned int NAME (char const *prog, char const *const *argv, char const *const *envp, unsigned int uid, unsigned int gid, int *fds)
{
int p[NPIPES][2] ;
int syncpipe[2] ;
int pid ;
int e ;
if (pipe(p[0]) < 0) return 0 ;
if (pipe(p[1]) < 0) { e = errno ; goto errp0 ; }
#ifdef _CHILD_SPAWN2_
if (pipe(p[2]) < 0) { e = errno ; goto errp1 ; }
#endif
if (pipe(syncpipe) < 0) { e = errno ; goto errp2 ; }
if (coe(syncpipe[1]) < 0) { e = errno ; goto errsp ; }
pid = fork() ;
if (pid < 0) { e = errno ; goto errsp ; }
else if (!pid)
{
unsigned int m = 25 ;
unsigned int n = str_len(PROG) ;
char fmt[25 + UINT_FMT] = "SKACLIENT2_ADDITIONAL_FD" ;
char name[n + 9] ;
byte_copy(name, n, PROG) ;
byte_copy(name + n, 9, " (child)") ;
PROG = name ;
#ifdef _CHILD_SPAWN2_
fmt[m-1] = '=' ;
m += uint_fmt(fmt + m, p[2][1]) ;
fmt[m++] = 0 ;
fd_close(p[2][0]) ;
#endif
fd_close(syncpipe[0]) ;
fd_close(p[1][1]) ;
fd_close(p[0][0]) ;
if ((fd_move(0, p[1][0]) < 0) || (fd_move(1, p[0][1]) < 0)) goto syncdie ;
if (gid && (prot_gid(gid) < 0)) goto syncdie ;
if (uid && (prot_uid(uid) < 0)) goto syncdie ;
/*
XXX: we should unignore signals here, but there's a compromise to be
XXX: found between bloat, API complexity, and theoretical correctness.
XXX: Not sure what The Right Thing is; just not unignoring atm.
XXX: 20130326 edit: The Right Thing is probably to leave the ignore
XXX: status alone, because programs that do actual signal handling
XXX: are likely to use a selfpipe, and selfpipe_finish() restores
XXX: old signal handlers - it knows what to do and we don't. So,
XXX: leave that work to selfpipe_finish().
*/
sig_blocknone() ; /* empty sigprocmask in the child, always */
pathexec_r_name(prog, argv, envp, env_len(envp), fmt, m) ;
syncdie:
{
char c = errno ;
fd_write(syncpipe[1], &c, 1) ;
}
_exit(111) ;
}
{
char c ;
fd_close(syncpipe[1]) ;
#ifdef _CHILD_SPAWN2_
fd_close(p[2][1]) ;
#endif
fd_close(p[1][0]) ;
fd_close(p[0][1]) ;
p[1][0] = fd_read(syncpipe[0], &c, 1) ;
if (p[1][0] < 0) goto killclosewait ;
else if (p[1][0]) { e = c ; goto closewait ; }
}
fd_close(syncpipe[0]) ;
if ((ndelay_on(p[0][0]) < 0) || (coe(p[0][0]) < 0)
|| (ndelay_on(p[1][1]) < 0) || (coe(p[1][1]) < 0)) goto killclosewait ;
#ifdef _CHILD_SPAWN2_
if ((ndelay_on(p[2][0]) < 0) || (coe(p[2][0]) < 0)) goto killclosewait ;
fds[2] = p[2][0] ;
#endif
fds[0] = p[0][0] ;
fds[1] = p[1][1] ;
return (unsigned int)pid ;
errsp:
fd_close(syncpipe[1]) ;
fd_close(syncpipe[0]) ;
errp2:
#ifdef _CHILD_SPAWN2_
fd_close(p[2][1]) ;
fd_close(p[2][0]) ;
errp1:
#endif
fd_close(p[1][1]) ;
fd_close(p[1][0]) ;
errp0:
fd_close(p[0][1]) ;
fd_close(p[0][0]) ;
errno = e ;
return 0 ;
killclosewait:
e = errno ;
kill(pid, SIGKILL) ;
closewait:
#ifdef _CHILD_SPAWN2_
fd_close(p[2][0]) ;
#endif
fd_close(p[1][1]) ;
fd_close(p[0][0]) ;
wait_pid(&syncpipe[1], pid) ;
errno = e ;
return 0 ;
}
