tinyweb.c

/*
 * Copyright (c) 2013-2014 Intel Corporation, All Rights Reserved
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms and conditions of the GNU General Public License,
 * version 2, as published by the Free Software Foundation.
 *
 * This program is distributed in the hope it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
 * more details.

Authors:
        Wang, Jing J <jing.j.wang@intel.com>
*/

#define _XOPEN_SOURCE 600  // For PATH_MAX on linux

#include <sys/stat.h>
#include <stdio.h>
#include <stdlib.h>
#include <signal.h>
#include <string.h>
#include <errno.h>
#include <limits.h>
#include <stddef.h>
#include <stdarg.h>
#include <ctype.h>
#include <dlfcn.h>
#include "mongoose.h"

#include <sys/wait.h>
#include <unistd.h>
#include <sys/stat.h>

#define DIRSEP '/'
#define WINCDECL

#define MAX_OPTIONS 40
#define MAX_CONF_FILE_LINE_SIZE (8 * 1024)
extern void websocket_ready_handler(struct mg_connection *);
extern int websocket_data_handler(struct mg_connection *, int, char *, size_t);
static int exit_flag;
static char server_name[40];        // Set by init_server_name()
static char config_file[PATH_MAX];  // Set by process_command_line_arguments()
static struct mg_context *ctx;      // Set by start_server()
#if !defined(CONFIG_FILE)
#define CONFIG_FILE "mongoose.conf"
#endif /* !CONFIG_FILE */
static void WINCDECL signal_handler(int sig_num) {
    exit_flag = sig_num;
}

static void die(const char *fmt, ...) {
  va_list ap;
  char msg[200];

  va_start(ap, fmt);
  vsnprintf(msg, sizeof(msg), fmt, ap);
  va_end(ap);

  fprintf(stderr, "%s\n", msg);

  exit(EXIT_FAILURE);
}

static void show_usage_and_exit(void) {
  const char **names;
  int i;

  fprintf(stderr, "Tinyweb version %s (c) jing wang, built on %s\n",
          mg_version(), __DATE__);
  fprintf(stderr, "Usage:\n");
  fprintf(stderr, "  tinyweb -A <htpasswd_file> <realm> <user> <passwd>\n");
  fprintf(stderr, "  tinyweb [config_file]\n");
  fprintf(stderr, "  tinyweb [-option value ...]\n");
  fprintf(stderr, "\nOPTIONS:\n");

  names = mg_get_valid_option_names();
  for (i = 0; names[i] != NULL; i += 2) {
    fprintf(stderr, "  -%s %s\n",
            names[i], names[i + 1] == NULL ? "<empty>" : names[i + 1]);
  }
  exit(EXIT_FAILURE);
}

static void verify_document_root(const char *root) {
  const char *p, *path;
  char buf[PATH_MAX];
  struct stat st;

  path = root;
  if ((p = strchr(root, ',')) != NULL && (size_t) (p - root) < sizeof(buf)) {
    memcpy(buf, root, p - root);
    buf[p - root] = '\0';
    path = buf;
  }

  if (stat(path, &st) != 0 || !S_ISDIR(st.st_mode)) {
    die("Invalid root directory: [%s]: %s", root, strerror(errno));
  }
}

static char *sdup(const char *str) {
  char *p;
  if ((p = (char *) malloc(strlen(str) + 1)) != NULL) {
    strcpy(p, str);
  }
  return p;
}

static void set_option(char **options, const char *name, const char *value) {
  int i;

  if (!strcmp(name, "document_root") || !(strcmp(name, "r"))) {
    verify_document_root(value);
  }

  for (i = 0; i < MAX_OPTIONS - 3; i++) {
    if (options[i] == NULL) {
      options[i] = sdup(name);
      options[i + 1] = sdup(value);
      options[i + 2] = NULL;
      break;
    }
  }

  if (i == MAX_OPTIONS - 3) {
    die("%s", "Too many options specified");
  }
}

static void process_command_line_arguments(char *argv[], char **options) {
  char line[MAX_CONF_FILE_LINE_SIZE], opt[sizeof(line)], val[sizeof(line)], *p;
  FILE *fp = NULL;
  size_t i, cmd_line_opts_start = 1, line_no = 0;

  options[0] = NULL;

  // Should we use a config file ?
  if (argv[1] != NULL && argv[1][0] != '-') {
    snprintf(config_file, sizeof(config_file), "%s", argv[1]);
    cmd_line_opts_start = 2;
  } else if ((p = strrchr(argv[0], DIRSEP)) == NULL) {
    // No command line flags specified. Look where binary lives
    snprintf(config_file, sizeof(config_file), "%s", CONFIG_FILE);
  } else {
    snprintf(config_file, sizeof(config_file), "%.*s%c%s",
             (int) (p - argv[0]), argv[0], DIRSEP, CONFIG_FILE);
  }

  fp = fopen(config_file, "r");

  // If config file was set in command line and open failed, die
  if (cmd_line_opts_start == 2 && fp == NULL) {
    die("Cannot open config file %s: %s", config_file, strerror(errno));
  }

  // Load config file settings first
  if (fp != NULL) {
    fprintf(stderr, "Loading config file %s\n", config_file);

    // Loop over the lines in config file
    while (fgets(line, sizeof(line), fp) != NULL) {
      line_no++;

      // Ignore empty lines and comments
      for (i = 0; isspace(* (unsigned char *) &line[i]); ) i++;
      if (line[i] == '#' || line[i] == '\0') {
        continue;
      }

      if (sscanf(line, "%s %[^\r\n#]", opt, val) != 2) {
        printf("%s: line %d is invalid, ignoring it:\n %s",
               config_file, (int) line_no, line);
      } else {
        set_option(options, opt, val);
      }
    }

    (void) fclose(fp);
  }

  // If we're under MacOS and started by launchd, then the second
  // argument is process serial number, -psn_.....
  // In this case, don't process arguments at all.
  if (argv[1] == NULL || memcmp(argv[1], "-psn_", 5) != 0) {
    // Handle command line flags.
    // They override config file and default settings.
    for (i = cmd_line_opts_start; argv[i] != NULL; i += 2) {
      if (argv[i][0] != '-' || argv[i + 1] == NULL) {
        show_usage_and_exit();
      }
      set_option(options, &argv[i][1], argv[i + 1]);
    }
  }
}

static void init_server_name(void) {
  snprintf(server_name, sizeof(server_name), "Tinyweb server v. %s",
           mg_version());
}

static int log_message(const struct mg_connection *conn, const char *message) {
  (void) conn;
  printf("%s\n", message);
  return 0;
}

static void start_server(int argc, char *argv[]) {
  struct mg_callbacks callbacks;
  char *options[MAX_OPTIONS];
  int i;

  // Edit passwords file if -A option is specified
  if (argc > 1 && !strcmp(argv[1], "-A")) {
    if (argc != 6) {
      show_usage_and_exit();
    }
    exit(mg_modify_passwords_file(argv[2], argv[3], argv[4], argv[5]) ?
         EXIT_SUCCESS : EXIT_FAILURE);
  }

  // Show usage if -h or --help options are specified
  if (argc == 2 && (!strcmp(argv[1], "-h") || !strcmp(argv[1], "--help"))) {
    show_usage_and_exit();
  }

  /* Update config based on command line arguments */
  process_command_line_arguments(argv, options);

  /* Setup signal handler: quit on Ctrl-C */
  signal(SIGTERM, signal_handler);
  signal(SIGINT, signal_handler);

  /* Start Tinyweb server */
  memset(&callbacks, 0, sizeof(callbacks));
  callbacks.websocket_ready = websocket_ready_handler;
  callbacks.websocket_data = websocket_data_handler;

  callbacks.log_message = &log_message;
  ctx = mg_start(&callbacks, NULL, (const char **) options);
  for (i = 0; options[i] != NULL; i++) {
    free(options[i]);
  }

  if (ctx == NULL) {
    die("%s", "Failed to start Tinyweb.");
  }
}

int main(int argc, char *argv[]) {
  signal(SIGCHLD, SIG_IGN);
  signal(SIGHUP, SIG_IGN);
  pid_t pid = 0;
  pid = fork();
  if (pid < 0) {
    fprintf(stderr, "fork failed!\n");
    exit(1);
  }
  if (pid > 0) {
    sleep(1);
    exit(0);
  }
  umask(0);
  setsid();
  chdir("/");

  init_server_name();
  start_server(argc, argv);
  pid = getpid();
  printf("%s started on port(s) %s with document root [%s], pid [%d]\n",
         server_name, mg_get_option(ctx, "listening_ports"),
         mg_get_option(ctx, "document_root"), pid);

  char *pidfile = (char *)mg_get_option(ctx, "pidfile");
  if (*pidfile) {
    FILE *fp = fopen(pidfile, "w+");
    fprintf(fp, "%d", pid);
    fclose(fp);
  }

  while (exit_flag == 0) {
    sleep(1);
  }
  printf("Exiting on signal %d, waiting for all threads to finish...",
         exit_flag);
  printf("%s", " done.\n");
  fflush(stdout);
  mg_stop(ctx);
  return EXIT_SUCCESS;
}