static void msg_write_response(int fd, rtsp_message *resp) {
char pkt[1024];
int pktfree = sizeof(pkt);
char *p = pkt;
int i, n;
n = snprintf(p, pktfree,
"RTSP/1.0 %d %s\r\n", resp->respcode,
resp->respcode==200 ? "OK" : "Error");
debug(1, "sending response: %s", pkt);
pktfree -= n;
p += n;
for (i=0; i<resp->nheaders; i++) {
debug(2, " %s: %s\n", resp->name[i], resp->value[i]);
n = snprintf(p, pktfree, "%s: %s\r\n", resp->name[i], resp->value[i]);
pktfree -= n;
p += n;
if (pktfree <= 0)
die("Attempted to write overlong RTSP packet");
}
if (pktfree < 3)
die("Attempted to write overlong RTSP packet");
strcpy(p, "\r\n");
write_unchecked(fd, pkt, p-pkt+2);
}
/*
* Do a fork followed by a execvp, handling execvp errors correctly.
* Return the pid of the new process upon success, or -1 if something failed.
* Check errno for error details.
*/
static int fork_execvp(const char *file, char *const argv[]) {
int execpipe[2];
int pid = 0;
if (pipe(execpipe) < 0) {
return -1;
}
if (fcntl(execpipe[1], F_SETFD, fcntl(execpipe[1], F_GETFD) | FD_CLOEXEC) < 0) {
close(execpipe[0]);
close(execpipe[1]);
return -1;
}
pid = fork();
if (pid < 0) {
close(execpipe[0]);
close(execpipe[1]);
return -1;
}
else if(pid == 0) { // Child
close(execpipe[0]); // Close the read end
execvp(file, argv);
// If we reach this point then execve has failed.
// Write erno's value into the pipe and exit.
write_unchecked(execpipe[1], &errno, sizeof(errno));
_exit(-1);
return 0; // Just to make the compiler happy.
}
else { // Parent
close(execpipe[1]); // Close the write end
int childErrno;
// Block until child closes the pipe or sends errno.
if(read(execpipe[0], &childErrno, sizeof(childErrno)) == sizeof(childErrno)) { // We received errno
errno = childErrno;
return -1;
}
else { // Child closed the pipe. execvp was successful.
return pid;
}
}
}