/*
This file is taken from lighttpd 1.4.10 (http://www.lighttpd.net/)

Copyright (c) 2004, Jan Kneschke, incremental
 All rights reserved.

Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are met:

- Redistributions of source code must retain the above copyright notice, this
  list of conditions and the following disclaimer.

- Redistributions in binary form must reproduce the above copyright notice,
  this list of conditions and the following disclaimer in the documentation
  and/or other materials provided with the distribution.

- Neither the name of the 'incremental' nor the names of its contributors may
  be used to endorse or promote products derived from this software without
  specific prior written permission.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" 
AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 
IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 
ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE 
LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 
CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 
SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 
INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 
CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 
ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF 
THE POSSIBILITY OF SUCH DAMAGE.
*/

#include <sys/types.h>
#include <sys/time.h>
#include <sys/stat.h>

#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <stdio.h>
#include <unistd.h>
#include <fcntl.h>

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif


#ifdef HAVE_PWD_H
#include <grp.h>
#include <pwd.h>
#endif

#ifdef HAVE_GETOPT_H
#include <getopt.h>
#endif

#define FCGI_LISTENSOCK_FILENO 0

#ifndef UNIX_PATH_MAX
# define UNIX_PATH_MAX 108
#endif

#include "sys-socket.h"

#ifdef HAVE_SYS_WAIT_H
#include <sys/wait.h>
#endif

/* for solaris 2.5 and netbsd 1.3.x */
#ifndef HAVE_SOCKLEN_T
typedef int socklen_t;
#endif

#ifdef HAVE_SYS_UN_H
int fcgi_spawn_connection(char *appPath, char *addr, unsigned short port, const char *unixsocket, int child_count, int pid_fd, int nofork) {
	int fcgi_fd;
	int socket_type, status;
	struct timeval tv = { 0, 100 * 1000 };

	struct sockaddr_un fcgi_addr_un;
	struct sockaddr_in fcgi_addr_in;
	struct sockaddr *fcgi_addr;

	socklen_t servlen;

	if (child_count < 2) {
		child_count = 5;
	}

	if (child_count > 256) {
		child_count = 256;
	}


	if (unixsocket) {
		memset(&fcgi_addr, 0, sizeof(fcgi_addr));

		fcgi_addr_un.sun_family = AF_UNIX;
		strcpy(fcgi_addr_un.sun_path, unixsocket);

#ifdef SUN_LEN
		servlen = SUN_LEN(&fcgi_addr_un);
#else
		/* stevens says: */
		servlen = strlen(fcgi_addr_un.sun_path) + sizeof(fcgi_addr_un.sun_family);
#endif
		socket_type = AF_UNIX;
		fcgi_addr = (struct sockaddr *) &fcgi_addr_un;
	} else {
		fcgi_addr_in.sin_family = AF_INET;
                if (addr != NULL) {
                        fcgi_addr_in.sin_addr.s_addr = inet_addr(addr);
                } else {
                        fcgi_addr_in.sin_addr.s_addr = htonl(INADDR_ANY);
                }
		fcgi_addr_in.sin_port = htons(port);
		servlen = sizeof(fcgi_addr_in);

		socket_type = AF_INET;
		fcgi_addr = (struct sockaddr *) &fcgi_addr_in;
	}

	if (-1 == (fcgi_fd = socket(socket_type, SOCK_STREAM, 0))) {
		fprintf(stderr, "%s.%d\n",
			__FILE__, __LINE__);
		return -1;
	}

	if (-1 == connect(fcgi_fd, fcgi_addr, servlen)) {
		/* server is not up, spawn in  */
		pid_t child;
		int val;

		if (unixsocket) unlink(unixsocket);

		close(fcgi_fd);

		/* reopen socket */
		if (-1 == (fcgi_fd = socket(socket_type, SOCK_STREAM, 0))) {
			fprintf(stderr, "%s.%d\n",
				__FILE__, __LINE__);
			return -1;
		}

		val = 1;
		if (setsockopt(fcgi_fd, SOL_SOCKET, SO_REUSEADDR, &val, sizeof(val)) < 0) {
			fprintf(stderr, "%s.%d\n",
				__FILE__, __LINE__);
			return -1;
		}

		/* create socket */
		if (-1 == bind(fcgi_fd, fcgi_addr, servlen)) {
			fprintf(stderr, "%s.%d: bind failed: %s\n",
				__FILE__, __LINE__,
				strerror(errno));
			return -1;
		}

		if (-1 == listen(fcgi_fd, 1024)) {
			fprintf(stderr, "%s.%d: fd = -1\n",
				__FILE__, __LINE__);
			return -1;
		}

		if (!nofork) {
			child = fork();
		} else {
			child = 0;
		}

		switch (child) {
		case 0: {
			char cgi_childs[64];
			char *b;

			int i = 0;

			/* is save as we limit to 256 childs */
			sprintf(cgi_childs, "PHP_FCGI_CHILDREN=%d", child_count);

			if(fcgi_fd != FCGI_LISTENSOCK_FILENO) {
				close(FCGI_LISTENSOCK_FILENO);
				dup2(fcgi_fd, FCGI_LISTENSOCK_FILENO);
				close(fcgi_fd);
			}

			/* we don't need the client socket */
			for (i = 3; i < 256; i++) {
				close(i);
			}

			/* create environment */

			putenv(cgi_childs);

			/* fork and replace shell */
			b = malloc(strlen("exec ") + strlen(appPath) + 1);
			strcpy(b, "exec ");
			strcat(b, appPath);

			/* exec the cgi */
			execl("/bin/sh", "sh", "-c", b, NULL);

			exit(errno);

			break;
		}
		case -1:
			/* error */
			break;
		default:
			/* father */

			/* wait */
			select(0, NULL, NULL, NULL, &tv);

			switch (waitpid(child, &status, WNOHANG)) {
			case 0:
				fprintf(stderr, "%s.%d: child spawned successfully: PID: %d\n",
					__FILE__, __LINE__,
					child);

				/* write pid file */
				if (pid_fd != -1) {
					/* assume a 32bit pid_t */
					char pidbuf[12];

					snprintf(pidbuf, sizeof(pidbuf) - 1, "%d", child);

					write(pid_fd, pidbuf, strlen(pidbuf));
					close(pid_fd);
					pid_fd = -1;
				}

				break;
			case -1:
				break;
			default:
				if (WIFEXITED(status)) {
					fprintf(stderr, "%s.%d: child exited with: %d, %s\n",
						__FILE__, __LINE__,
						WEXITSTATUS(status), strerror(WEXITSTATUS(status)));
				} else if (WIFSIGNALED(status)) {
					fprintf(stderr, "%s.%d: child signaled: %d\n",
						__FILE__, __LINE__,
						WTERMSIG(status));
				} else {
					fprintf(stderr, "%s.%d: child died somehow: %d\n",
						__FILE__, __LINE__,
						status);
				}
			}

			break;
		}
	} else {
		fprintf(stderr, "%s.%d: socket is already used, can't spawn\n",
			__FILE__, __LINE__);
		return -1;
	}

	close(fcgi_fd);

	return 0;
}


void show_version () {
	char *b = "spawn-fcgi" "-" PACKAGE_VERSION \
" - spawns fastcgi processes\n"
;
	write(1, b, strlen(b));
}

void show_help () {
	char *b = "spawn-fcgi" "-" PACKAGE_VERSION \
" - spawns fastcgi processes\n" \
"usage:\n" \
" -f <fcgiapp> filename of the fcgi-application\n" \
" -a <addr>    bind to ip address\n" \
" -p <port>    bind to tcp-port\n" \
" -s <path>    bind to unix-domain socket\n" \
" -C <childs>  (PHP only) numbers of childs to spawn (default 5)\n" \
" -P <path>    name of PID-file for spawed process\n" \
" -n           no fork (for daemontools)\n" \
" -v           show version\n" \
" -h           show this help\n" \
"(root only)\n" \
" -c <dir>     chroot to directory\n" \
" -u <user>    change to user-id\n" \
" -g <group>   change to group-id\n" \
;
	write(1, b, strlen(b));
}


int main(int argc, char **argv) {
	char *fcgi_app = NULL, *changeroot = NULL, *username = NULL,
               *groupname = NULL, *unixsocket = NULL, *pid_file = NULL,
                *addr = NULL;
	unsigned short port = 0;
	int child_count = 5;
	int i_am_root, o;
	int pid_fd = -1;
	int nofork = 0;

	i_am_root = (getuid() == 0);

       while(-1 != (o = getopt(argc, argv, "c:f:g:hna:p:u:vC:s:P:"))) {
		switch(o) {
		case 'f': fcgi_app = optarg; break;
               case 'a': addr = optarg;/* ip addr */ break;
		case 'p': port = strtol(optarg, NULL, 10);/* port */ break;
		case 'C': child_count = strtol(optarg, NULL, 10);/*  */ break;
		case 's': unixsocket = optarg; /* unix-domain socket */ break;
		case 'c': if (i_am_root) { changeroot = optarg; }/* chroot() */ break;
		case 'u': if (i_am_root) { username = optarg; } /* set user */ break;
		case 'g': if (i_am_root) { groupname = optarg; } /* set group */ break;
		case 'n': nofork = 1; break;
		case 'P': pid_file = optarg; /* PID file */ break;
		case 'v': show_version(); return 0;
		case 'h': show_help(); return 0;
		default:
			show_help();
			return -1;
		}
	}

	if (fcgi_app == NULL || (port == 0 && unixsocket == NULL)) {
		show_help();
		return -1;
	}

	if (unixsocket && port) {
		fprintf(stderr, "%s.%d: %s\n",
			__FILE__, __LINE__,
			"either a unix domain socket or a tcp-port, but not both\n");

		return -1;
	}

	if (unixsocket && strlen(unixsocket) > UNIX_PATH_MAX - 1) {
		fprintf(stderr, "%s.%d: %s\n",
			__FILE__, __LINE__,
			"path of the unix socket is too long\n");

		return -1;
	}

	/* UID handling */
	if (!i_am_root && (geteuid() == 0 || getegid() == 0)) {
		/* we are setuid-root */

		fprintf(stderr, "%s.%d: %s\n",
			__FILE__, __LINE__,
			"Are you nuts ? Don't apply a SUID bit to this binary\n");

		return -1;
	}

	if (pid_file &&
	    (-1 == (pid_fd = open(pid_file, O_WRONLY | O_CREAT | O_EXCL | O_TRUNC, S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH)))) {
		struct stat st;
		if (errno != EEXIST) {
			fprintf(stderr, "%s.%d: opening pid-file '%s' failed: %s\n",
				__FILE__, __LINE__,
				pid_file, strerror(errno));

			return -1;
		}

		/* ok, file exists */

		if (0 != stat(pid_file, &st)) {
			fprintf(stderr, "%s.%d: stating pid-file '%s' failed: %s\n",
				__FILE__, __LINE__,
				pid_file, strerror(errno));

			return -1;
		}

		/* is it a regular file ? */

		if (!S_ISREG(st.st_mode)) {
			fprintf(stderr, "%s.%d: pid-file exists and isn't regular file: '%s'\n",
				__FILE__, __LINE__,
				pid_file);

			return -1;
		}

		if (-1 == (pid_fd = open(pid_file, O_WRONLY | O_CREAT | O_TRUNC, S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH))) {
			fprintf(stderr, "%s.%d: opening pid-file '%s' failed: %s\n",
				__FILE__, __LINE__,
				pid_file, strerror(errno));

			return -1;
		}
	}

	if (i_am_root) {
		struct group *grp = NULL;
		struct passwd *pwd = NULL;

		/* set user and group */

		if (username) {
			if (NULL == (pwd = getpwnam(username))) {
				fprintf(stderr, "%s.%d: %s, %s\n",
					__FILE__, __LINE__,
					"can't find username", username);
				return -1;
			}

			if (pwd->pw_uid == 0) {
				fprintf(stderr, "%s.%d: %s\n",
					__FILE__, __LINE__,
					"I will not set uid to 0\n");
				return -1;
			}
		}

		if (groupname) {
			if (NULL == (grp = getgrnam(groupname))) {
				fprintf(stderr, "%s.%d: %s %s\n",
					__FILE__, __LINE__,
					"can't find groupname",
					groupname);
				return -1;
			}
			if (grp->gr_gid == 0) {
				fprintf(stderr, "%s.%d: %s\n",
					__FILE__, __LINE__,
					"I will not set gid to 0\n");
				return -1;
			}
		}

		if (changeroot) {
			if (-1 == chroot(changeroot)) {
				fprintf(stderr, "%s.%d: %s %s\n",
					__FILE__, __LINE__,
					"chroot failed: ", strerror(errno));
				return -1;
			}
			if (-1 == chdir("/")) {
				fprintf(stderr, "%s.%d: %s %s\n",
					__FILE__, __LINE__,
					"chdir failed: ", strerror(errno));
				return -1;
			}
		}

		/* drop root privs */
		if (groupname) {
			setgid(grp->gr_gid);
		}
		if (username) {
			if (groupname) {
				initgroups(username, grp->gr_gid);
			}
			setuid(pwd->pw_uid);
		}
	}

       return fcgi_spawn_connection(fcgi_app, addr, port, unixsocket, child_count, pid_fd, nofork);
}
#else
int main() {
	return -1;
}
#endif