/*-
 * Copyright (c) 2005-2006 Robert N. M. Watson
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. 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.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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/mman.h>
#include <sys/socket.h>
#include <sys/uio.h>
#include <sys/utsname.h>
#include <sys/wait.h>

#include <netinet/in.h>

#include <arpa/inet.h>

#include <err.h>
#include <errno.h>
#include <fcntl.h>
#include <limits.h>
#include <pthread.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sysexits.h>
#include <unistd.h>

static int      threaded;               /* 1 for threaded, 0 for forked. */

/*
 * Simple, multi-threaded/multi-process HTTP server.  Very dumb.
 *
 * If a path is specified as an argument, only that file is served.  If no
 * path is specified, httpd will create one file to send per server thread.
 */
#define THREADS         128
#define BUFFER          1024
#define FILESIZE        1024

#define HTTP_OK         "HTTP/1.1 200 OK\n"
#define HTTP_SERVER1    "Server rwatson_httpd/1.0 ("
#define HTTP_SERVER2    ")\n"
#define HTTP_CONNECTION "Connection: close\n"
#define HTTP_CONTENT    "Content-Type: text/html\n\n"

/*
 * In order to support both multi-threaded and multi-process operation but
 * use a single shared memory statistics model, we create a page-aligned
 * statistics buffer.  For threaded operation, it's just shared memory due to
 * threading; for multi-process operation, we mark it as INHERIT_SHARE, so we
 * must put it in page-aligned memory that isn't shared with other memory, or
 * risk accidental sharing of other statep.
 */
static struct state {
        struct httpd_thread_statep {
                pthread_t       hts_thread;     /* Multi-thread. */
                pid_t           hts_pid;        /* Multi-process. */
                int             hts_fd;
        } hts[THREADS];

        const char      *path;
        int              data_file;
        int              listen_sock;
        struct utsname   utsname;
} *statep;

/*
 * Borrowed from sys/param.h.
 */
#define roundup(x, y)   ((((x)+((y)-1))/(y))*(y))       /* to any y */

/*
 * Given an open client socket, process its request.  No notion of timeout.
 */
static int
http_serve(int sock, int fd)
{
        struct iovec header_iovec[6];
        struct sf_hdtr sf_hdtr;
        char buffer[BUFFER];
        ssize_t len;
        int i, ncount;

        /* Read until \n\n.  Not very smart. */
        ncount = 0;
        while (1) {
                len = recv(sock, buffer, BUFFER, 0);
                if (len < 0) {
                        warn("recv");
                        return (-1);
                }
                if (len == 0)
                        return (-1);
                for (i = 0; i < len; i++) {
                        switch (buffer[i]) {
                        case '\n':
                                ncount++;
                                break;

                        case '\r':
                                break;

                        default:
                                ncount = 0;
                        }
                }
                if (ncount == 2)
                        break;
        }

        bzero(&sf_hdtr, sizeof(sf_hdtr));
        bzero(&header_iovec, sizeof(header_iovec));
        header_iovec[0].iov_base = HTTP_OK;
        header_iovec[0].iov_len = strlen(HTTP_OK);
        header_iovec[1].iov_base = HTTP_SERVER1;
        header_iovec[1].iov_len = strlen(HTTP_SERVER1);
        header_iovec[2].iov_base = statep->utsname.sysname;
        header_iovec[2].iov_len = strlen(statep->utsname.sysname);
        header_iovec[3].iov_base = HTTP_SERVER2;
        header_iovec[3].iov_len = strlen(HTTP_SERVER2);
        header_iovec[4].iov_base = HTTP_CONNECTION;
        header_iovec[4].iov_len = strlen(HTTP_CONNECTION);
        header_iovec[5].iov_base = HTTP_CONTENT;
        header_iovec[5].iov_len = strlen(HTTP_CONTENT);
        sf_hdtr.headers = header_iovec;
        sf_hdtr.hdr_cnt = 6;
        sf_hdtr.trailers = NULL;
        sf_hdtr.trl_cnt = 0;

        if (sendfile(fd, sock, 0, 0, &sf_hdtr, NULL, 0) < 0)
                warn("sendfile");

        return (0);
}

static void *
httpd_worker(void *arg)
{
        struct httpd_thread_statep *htsp;
        int sock;

        htsp = arg;

        while (1) {
                sock = accept(statep->listen_sock, NULL, NULL);
                if (sock < 0)
                        continue;
                (void)http_serve(sock, htsp->hts_fd);
                close(sock);
        }
}

static void
killall(void)
{
        int i;

        for (i = 0; i < THREADS; i++) {
                if (statep->hts[i].hts_pid != 0)
                        (void)kill(statep->hts[i].hts_pid, SIGTERM);
        }
}

static void
usage(void)
{

        fprintf(stderr, "httpd [-t] port [path]\n");
        exit(EX_USAGE);
}

int
main(int argc, char *argv[])
{
        u_char filebuffer[FILESIZE];
        char temppath[PATH_MAX];
        struct sockaddr_in sin;
        int ch, error, i;
        char *pagebuffer;
        ssize_t len;
        pid_t pid;


        while ((ch = getopt(argc, argv, "t")) != -1) {
                switch (ch) {
                case 't':
                        threaded = 1;
                        break;

                default:
                        usage();
                }
        }
        argc -= optind;
        argv += optind;

        if (argc != 1 && argc != 2)
                usage();

        len = roundup(sizeof(struct state), getpagesize());
        pagebuffer = mmap(NULL, len, PROT_READ | PROT_WRITE, MAP_ANON, -1, 0);
        if (pagebuffer == MAP_FAILED)
                err(-1, "mmap");
        if (minherit(pagebuffer, len, INHERIT_SHARE) < 0)
                err(-1, "minherit");
        statep = (struct state *)pagebuffer;

        if (uname(&statep->utsname) < 0)
                err(-1, "utsname");

        statep->listen_sock = socket(PF_INET, SOCK_STREAM, 0);
        if (statep->listen_sock < 0)
                err(-1, "socket(PF_INET, SOCK_STREAM)");

        bzero(&sin, sizeof(sin));
        sin.sin_len = sizeof(sin);
        sin.sin_family = AF_INET;
        sin.sin_port = htons(atoi(argv[0]));

        /*
         * If a path is specified, use it.  Otherwise, create temporary files
         * with some data for each thread.
         */
        statep->path = argv[1];
        if (statep->path != NULL) {
                statep->data_file = open(statep->path, O_RDONLY);
                if (statep->data_file < 0)
                        err(-1, "open: %s", statep->path);
                for (i = 0; i < THREADS; i++)
                        statep->hts[i].hts_fd = statep->data_file;
        } else {
                memset(filebuffer, 'A', FILESIZE - 1);
                filebuffer[FILESIZE - 1] = '\n';
                for (i = 0; i < THREADS; i++) {
                        snprintf(temppath, PATH_MAX, "/tmp/httpd.XXXXXXXXXXX");
                        statep->hts[i].hts_fd = mkstemp(temppath);
                        if (statep->hts[i].hts_fd < 0)
                                err(-1, "mkstemp");
                        (void)unlink(temppath);
                        len = write(statep->hts[i].hts_fd, filebuffer,
                            FILESIZE);
                        if (len < 0)
                                err(-1, "write");
                        if (len < FILESIZE)
                                errx(-1, "write: short");
                }
        }

        if (bind(statep->listen_sock, (struct sockaddr *)&sin,
            sizeof(sin)) < 0)
                err(-1, "bind");

        if (listen(statep->listen_sock, -1) < 0)
                err(-1, "listen");

        for (i = 0; i < THREADS; i++) {
                if (threaded) {
                        if (pthread_create(&statep->hts[i].hts_thread, NULL,
                            httpd_worker, &statep->hts[i]) != 0)
                                err(-1, "pthread_create");
                } else {
                        pid = fork();
                        if (pid < 0) {
                                error = errno;
                                killall();
                                errno = error;
                                err(-1, "fork");
                        }
                        if (pid == 0)
                                httpd_worker(&statep->hts[i]);
                        statep->hts[i].hts_pid = pid;
                }
        }

        for (i = 0; i < THREADS; i++) {
                if (threaded) {
                        if (pthread_join(statep->hts[i].hts_thread, NULL)
                            != 0)
                                err(-1, "pthread_join");
                } else {
                        pid = waitpid(statep->hts[i].hts_pid, NULL, 0);
                        if (pid == statep->hts[i].hts_pid)
                                statep->hts[i].hts_pid = 0;
                }
        }
        if (!threaded)
                killall();
        return (0);
}