beanstalkd.c

   1 /* beanstalk - fast, general-purpose work queue */
   2
   3 /* Copyright (C) 2007 Keith Rarick and Philotic Inc.
   4
   5  * This program is free software: you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation, either version 3 of the License, or
   8  * (at your option) any later version.
   9
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  * GNU General Public License for more details.
  14
  15  * You should have received a copy of the GNU General Public License
  16  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  17  */
  18
  19 #include <signal.h>
  20 #include <stdio.h>
  21 #include <stdlib.h>
  22 #include <errno.h>
  23 #include <sys/stat.h>
  24 #include <sys/resource.h>
  25 #include <sys/socket.h>
  26 #include <netinet/in.h>
  27 #include <arpa/inet.h>
  28 #include <sys/types.h>
  29 #include <unistd.h>
  30 #include <pwd.h>
  31 #include <event.h>
  32
  33 #include "net.h"
  34 #include "util.h"
  35 #include "prot.h"
  36
  37 static char *user = NULL;
  38 static int detach = 0;
  39 static int port = 11300;
  40 static struct in_addr host_addr = { INADDR_ANY };
  41
  42 static void
  43 nullfd(int fd, int flags)
  44 {
  45     int r;
  46
  47     close(fd);
  48     r = open("/dev/null", flags);
  49     if (r != fd) twarn("open(\"/dev/null\")"), exit(1);
  50 }
  51
  52 static void
  53 dfork()
  54 {
  55     pid_t p;
  56
  57     p = fork();
  58     if (p == -1) exit(1);
  59     if (p) exit(0);
  60 }
  61
  62 static void
  63 daemonize()
  64 {
  65     chdir("/");
  66     nullfd(0, O_RDONLY);
  67     nullfd(1, O_WRONLY);
  68     nullfd(2, O_WRONLY);
  69     umask(0);
  70     dfork();
  71     setsid();
  72     dfork();
  73 }
  74
  75 static void
  76 su(const char *user) {
  77     int r;
  78     struct passwd *pwent;
  79
  80     errno = 0;
  81     pwent = getpwnam(user);
  82     if (errno) twarn("getpwnam(\"%s\")", user), exit(32);
  83     if (!pwent) twarnx("getpwnam(\"%s\"): no such user", user), exit(33);
  84
  85     r = setgid(pwent->pw_gid);
  86     if (r == -1) twarn("setgid(%d \"%s\")", pwent->pw_gid, user), exit(34);
  87
  88     r = setuid(pwent->pw_uid);
  89     if (r == -1) twarn("setuid(%d \"%s\")", pwent->pw_uid, user), exit(34);
  90 }
  91
  92 void
  93 exit_cleanly(int sig)
  94 {
  95     exit(0);
  96 }
  97
  98
  99 static void
 100 set_sig_handlers()
 101 {
 102     int r;
 103     struct sigaction sa;
 104
 105     sa.sa_handler = SIG_IGN;
 106     sa.sa_flags = 0;
 107     r = sigemptyset(&sa.sa_mask);
 108     if (r == -1) twarn("sigemptyset()"), exit(111);
 109
 110     r = sigaction(SIGPIPE, &sa, 0);
 111     if (r == -1) twarn("sigaction(SIGPIPE)"), exit(111);
 112
 113     sa.sa_handler = enter_drain_mode;
 114     r = sigaction(SIGUSR1, &sa, 0);
 115     if (r == -1) twarn("sigaction(SIGUSR1)"), exit(111);
 116
 117     sa.sa_handler = exit_cleanly;
 118     r = sigaction(SIGINT, &sa, 0);
 119     if (r == -1) twarn("sigaction(SIGINT)"), exit(111);
 120 }
 121
 122 /* This is a workaround for a mystifying workaround in libevent's epoll
 123  * implementation. The epoll_init() function creates an epoll fd with space to
 124  * handle RLIMIT_NOFILE - 1 fds, accompanied by the following puzzling comment:
 125  * "Solaris is somewhat retarded - it's important to drop backwards
 126  * compatibility when making changes. So, don't dare to put rl.rlim_cur here."
 127  * This is presumably to work around a bug in Solaris, but it has the
 128  * unfortunate side-effect of causing epoll_ctl() (and, therefore, event_add())
 129  * to fail for a valid fd if we have hit the limit of open fds. That makes it
 130  * hard to provide reasonable behavior in that situation. So, let's reduce the
 131  * real value of RLIMIT_NOFILE by one, after epoll_init() has run. */
 132 static void
 133 nudge_fd_limit()
 134 {
 135     int r;
 136     struct rlimit rl;
 137
 138     r = getrlimit(RLIMIT_NOFILE, &rl);
 139     if (r != 0) twarn("getrlimit(RLIMIT_NOFILE)"), exit(2);
 140
 141     rl.rlim_cur--;
 142
 143     r = setrlimit(RLIMIT_NOFILE, &rl);
 144     if (r != 0) twarn("setrlimit(RLIMIT_NOFILE)"), exit(2);
 145 }
 146
 147 static void
 148 usage(char *msg, char *arg)
 149 {
 150     if (arg) warnx("%s: %s", msg, arg);
 151     fprintf(stderr, "Use: %s [OPTIONS]\n"
 152             "\n"
 153             "Options:\n"
 154             " -d       detach\n"
 155             " -l ADDR  listen on address (default is 0.0.0.0)\n"
 156             " -p PORT  listen on port (default is 11300)\n"
 157             " -u USER  become user and group\n"
 158             " -z SIZE  set the maximum job size\n"
 159             " -h       show this help\n",
 160             progname);
 161     exit(arg ? 5 : 0);
 162 }
 163
 164 static size_t
 165 parse_size_t(char *str)
 166 {
 167     char r, x;
 168     size_t size;
 169
 170     r = sscanf(str, "%zu%c", &size, &x);
 171     if (1 != r) usage("invalid size", str);
 172     return size;
 173 }
 174
 175 static int
 176 parse_port(char *portstr)
 177 {
 178     int port;
 179     char *end;
 180
 181     errno = 0;
 182     port = strtol(portstr, &end, 10);
 183     if (end == portstr) usage("invalid port", portstr);
 184     if (end[0] != 0) usage("invalid port", portstr);
 185     if (errno) usage("invalid port", portstr);
 186
 187    return port;
 188 }
 189
 190 static struct in_addr
 191 parse_host(char *hoststr)
 192 {
 193     int r;
 194     struct in_addr addr;
 195
 196     r = inet_aton(hoststr, &addr);
 197     if (!r) usage("invalid address", hoststr);
 198
 199     return addr;
 200 }
 201
 202 static void
 203 opts(int argc, char **argv)
 204 {
 205     int i;
 206
 207     for (i = 1; i < argc; ++i) {
 208         if (argv[i][0] != '-') usage("unknown option", argv[i]);
 209         if (argv[i][1] == 0 || argv[i][2] != 0) usage("unknown option",argv[i]);
 210         switch (argv[i][1]) {
 211             case 'd':
 212                 detach = 1;
 213                 break;
 214             case 'p':
 215                 port = parse_port(argv[++i]);
 216                 break;
 217             case 'l':
 218                 host_addr = parse_host(argv[++i]);
 219                 break;
 220             case 'z':
 221                 job_data_size_limit = parse_size_t(argv[++i]);
 222                 break;
 223             case 'u':
 224                 user = argv[++i];
 225                 break;
 226             case 'h':
 227                 usage(NULL, NULL);
 228             default:
 229                 usage("unknown option", argv[i]);
 230         }
 231     }
 232 }
 233
 234 int
 235 main(int argc, char **argv)
 236 {
 237     int r;
 238
 239     progname = argv[0];
 240     opts(argc, argv);
 241
 242     job_init();
 243     prot_init();
 244
 245     r = make_server_socket(host_addr, port);
 246     if (r == -1) twarnx("make_server_socket()"), exit(111);
 247
 248     if (user) su(user);
 249     if (detach) daemonize();
 250     event_init();
 251     set_sig_handlers();
 252     nudge_fd_limit();
 253
 254     unbrake((evh) h_accept);
 255
 256     event_dispatch();
 257     twarnx("got here for some reason");
 258     return 0;
 259 }