static int carbon_write(int fd, char *fmt,...) {
va_list ap;
va_start(ap, fmt);
char ptr[4096];
int rlen;
rlen = vsnprintf(ptr, 4096, fmt, ap);
va_end(ap);
if (rlen < 1) return 0;
if (uwsgi_write_nb(fd, ptr, rlen, u_carbon.timeout)) {
uwsgi_error("carbon_write()");
return 0;
}
return 1;
}
void uwsgi_fork_server(char *socket) {
// map fd 0 to /dev/null to avoid mess
uwsgi_remap_fd(0, "/dev/null");
int fd = bind_to_unix(socket, uwsgi.listen_queue, uwsgi.chmod_socket, uwsgi.abstract_socket);
if (fd < 0) exit(1);
// automatically receive credentials (TODO make something useful with them, like checking the pid is from the Emperor)
if (uwsgi_socket_passcred(fd)) exit(1);
// initialize the event queue
int eq = event_queue_init();
if (uwsgi.has_emperor) {
event_queue_add_fd_read(eq, uwsgi.emperor_fd);
}
event_queue_add_fd_read(eq, fd);
// now start waiting for connections
for(;;) {
int interesting_fd = -1;
int rlen = event_queue_wait(eq, -1, &interesting_fd);
if (rlen <= 0) continue;
if (uwsgi.has_emperor && interesting_fd == uwsgi.emperor_fd) {
char byte;
ssize_t rlen = read(uwsgi.emperor_fd, &byte, 1);
if (rlen > 0) {
uwsgi_log_verbose("received message %d from emperor\n", byte);
}
exit(0);
}
if (interesting_fd != fd) continue;
struct sockaddr_un client_src;
socklen_t client_src_len = 0;
int client_fd = accept(fd, (struct sockaddr *) &client_src, &client_src_len);
if (client_fd < 0) {
uwsgi_error("uwsgi_fork_server()/accept()");
continue;
}
char hbuf[4];
pid_t ppid = -1;
uid_t uid = -1;
gid_t gid = -1;
int fds_count = 8;
size_t remains = 4;
// we can receive up to 8 fds (generally from 1 to 3)
int fds[8];
// we only read 4 bytes header
ssize_t len = uwsgi_recv_cred_and_fds(client_fd, hbuf, remains, &ppid, &uid, &gid, fds, &fds_count);
uwsgi_log_verbose("[uwsgi-fork-server] connection from pid: %d uid: %d gid:%d fds:%d\n", ppid, uid, gid, fds_count);
if (len <= 0 || fds_count < 1) {
uwsgi_error("uwsgi_fork_server()/recvmsg()");
goto end;
}
remains -= len;
if (uwsgi_read_nb(client_fd, hbuf + (4-remains), remains, uwsgi.socket_timeout)) {
uwsgi_error("uwsgi_fork_server()/uwsgi_read_nb()");
goto end;
}
struct uwsgi_header *uh = (struct uwsgi_header *) hbuf;
// this memory area must be freed in the right place !!!
char *body_argv = uwsgi_malloc(uh->_pktsize);
if (uwsgi_read_nb(client_fd, body_argv, uh->_pktsize, uwsgi.socket_timeout)) {
free(body_argv);
uwsgi_error("uwsgi_fork_server()/uwsgi_read_nb()");
goto end;
}
pid_t pid = fork();
if (pid < 0) {
free(body_argv);
int i;
for(i=0;i<fds_count;i++) close(fds[i]);
// error on fork()
uwsgi_error("uwsgi_fork_server()/fork()");
goto end;
}
else if (pid > 0) {
free(body_argv);
// close inherited decriptors
int i;
for(i=0;i<fds_count;i++) close(fds[i]);
// wait for child death...
waitpid(pid, NULL, 0);
goto end;
}
else {
// close Emperor channels
// we do not close others file desctiptor as lot
// of funny tricks could be accomplished with them
if (uwsgi.has_emperor) {
close(uwsgi.emperor_fd);
if (uwsgi.emperor_fd_config > -1) close(uwsgi.emperor_fd_config);
}
// set EMPEROR_FD and FD_CONFIG env vars
char *uef = uwsgi_num2str(fds[0]);
if (setenv("UWSGI_EMPEROR_FD", uef, 1)) {
uwsgi_error("uwsgi_fork_server()/setenv()");
exit(1);
}
free(uef);
int pipe_config = -1;
int on_demand = -1;
if (uh->modifier2 & VASSAL_HAS_CONFIG && fds_count > 1) {
pipe_config = fds[1];
char *uef = uwsgi_num2str(pipe_config);
if (setenv("UWSGI_EMPEROR_FD_CONFIG", uef, 1)) {
uwsgi_error("uwsgi_fork_server()/setenv()");
exit(1);
}
free(uef);
}
if (uh->modifier2 & VASSAL_HAS_ON_DEMAND && fds_count > 1) {
if (pipe_config > -1) {
if (fds_count > 2) {
on_demand = fds[2];
}
}
else {
on_demand = fds[1];
}
}
// dup the on_demand socket to 0 and close it
if (on_demand > -1) {
if (dup2(on_demand, 0) < 0) {
uwsgi_error("uwsgi_fork_server()/dup2()");
exit(1);
}
close(on_demand);
}
// now fork again and die
pid_t new_pid = fork();
if (new_pid < 0) {
uwsgi_error("uwsgi_fork_server()/fork()");
exit(1);
}
else if (new_pid > 0) {
exit(0);
}
else {
// send the pid to the client_fd and close it
struct uwsgi_buffer *ub = uwsgi_buffer_new(uwsgi.page_size);
// leave space for header
ub->pos = 4;
if (uwsgi_buffer_append_keynum(ub, "pid", 3, getpid())) exit(1);
// fix uwsgi header
if (uwsgi_buffer_set_uh(ub, 35, 0)) goto end;
// send_pid()
if (uwsgi_write_nb(client_fd, ub->buf, ub->pos, uwsgi.socket_timeout)) exit(1);
close(client_fd);
uwsgi_log("double fork() and reparenting successful (new pid: %d)\n", getpid());
uwsgi_buffer_destroy(ub);
// now parse the uwsgi packet array and build the argv
struct uwsgi_string_list *usl = NULL, *usl_argv = NULL;
uwsgi_hooked_parse_array(body_argv, uh->_pktsize, parse_argv_hook, &usl_argv);
free(body_argv);
// build new argc/argv
uwsgi.new_argc = 0;
size_t procname_len = 1;
uwsgi_foreach(usl, usl_argv) {
uwsgi.new_argc++;
procname_len += usl->len + 1;
}
char *new_procname = uwsgi_calloc(procname_len);
uwsgi.new_argv = uwsgi_calloc(sizeof(char *) * (uwsgi.new_argc + 1));
int counter = 0;
uwsgi_foreach(usl, usl_argv) {
uwsgi.new_argv[counter] = usl->value;
strcat(new_procname, usl->value);
strcat(new_procname, " ");
counter++;
}
// fix process name
uwsgi_set_processname(new_procname);
free(new_procname);
// this is the only step required to have a consistent environment
uwsgi.fork_socket = NULL;
// this avoids the process to re-exec itself
uwsgi.exit_on_reload = 1;
// fixup the Emperor communication
uwsgi_check_emperor();
// continue with uWSGI startup
return;
}
}
