void
getfilenoise (datasink *dst, const char *path, cbv cb, size_t maxbytes)
{
int fds[2];
if (pipe (fds) < 0)
fatal ("pipe: %m\n");
pid_t pid = afork ();
if (pid == -1)
(*cb) ();
else if (!pid) {
close (fds[0]);
int fd = open (path, O_RDONLY|O_NONBLOCK, 0);
if (fd < 0) {
fatal ("%s: %m\n", path);
_exit (1);
return;
}
for (;;) {
char buf[1024];
size_t n = read (fd, buf, min (maxbytes, sizeof (buf)));
if (n <= 0)
_exit (0);
v_write (fds[1], buf, n);
maxbytes -= n;
if (!maxbytes)
_exit (0);
}
}
else {
close (fds[1]);
close_on_exec (fds[0]);
getprognoise (dst, fds[0], pid, cb);
}
}
static void
sigcatch (int sig)
{
sigdocheck = 1;
sigcaught[sig] = 1;
selwait.tv_sec = selwait.tv_usec = 0;
/* On some operating systems, select is not a system call but is
* implemented inside libc. This may cause a race condition in
* which select ends up being called with the original (non-zero)
* value of selwait. We avoid the problem by writing to a pipe that
* will wake up the select. */
v_write (sigpipes[1], "", 1);
}
pid_t
spawn (const char *path, char *const *argv,
int in, int out, int err, cbv::ptr postforkcb, char *const *env)
{
int fds[2];
if (pipe (fds) < 0)
return -1;
close_on_exec (fds[0]);
close_on_exec (fds[1]);
pid_t pid = afork ();
if (pid < 0)
return pid;
if (!pid) {
amain_panic = true;
close (fds[0]);
setstdfds (in, out, err);
if (postforkcb)
(*postforkcb) ();
if (env)
execve (path, argv, env);
else
execv (path, argv);
int saved_err = errno;
v_write (fds[1], &saved_err, sizeof (saved_err));
close (fds[1]);
// Since we return a useful errno, there is no need to print
// anything in the child process. Just exit.
_exit (1);
}
close (fds[1]);
int chld_err;
int n = read (fds[0], &chld_err, sizeof (chld_err));
close (fds[0]);
if (n == 0)
return pid;
errno = chld_err;
return -1;
}