src/tomd/main.c

   1 /* Copyright (C) 2018 Thomas Balzer */
   2
   3 /* This file is part of tomd. */
   4
   5 /* tomd 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 /* tomd 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 tomd.  If not, see <http://www.gnu.org/licenses/>. */
  17
  18 #include <stddef.h>
  19 #include <stdio.h>
  20 #include <errno.h>
  21 #include <stdlib.h>
  22 #include <unistd.h>
  23 #include <string.h>
  24 #include <sys/un.h>
  25 #include <sys/stat.h>
  26 #include <sys/socket.h>
  27
  28 #include "../../include/macros.h"
  29 #include "../../include/manifest.h"
  30
  31 static void header(void)
  32 {
  33   tomd_p("Tom's Daemon, Copyright (C) 2018 Thomas Balzer");
  34   tomd_p("GPL v3 or later license.");
  35 }
  36
  37 static int sfd;
  38 static char socket_dirname[100];
  39 static char socket_filename[100];
  40
  41 static void gen_socket_filename(void)
  42 {
  43   uid_t this_user_id =
  44     getuid();
  45   sprintf(socket_dirname,
  46           "/run/user/%d/tomd",
  47           this_user_id);
  48   sprintf(socket_filename,
  49           "/run/user/%d/tomd/socket",
  50           this_user_id);
  51
  52   tomd_p("making dir '%s'", socket_dirname);
  53   /* lazy way */
  54   char buf[100];
  55   sprintf(buf, "mkdir -p %s", socket_dirname);
  56   system(buf);
  57   /* if(mkdir(socket_dirname, S_IRWXU) != 0){ */
  58   /*   perror("socket mkdir"); */
  59   /*   exit(EXIT_FAILURE); */
  60   /* } */
  61
  62   tomd_p("removing file '%s'", socket_filename);
  63   if(unlink(socket_filename) != 0){
  64     if(errno == ENOENT){
  65       tomd_p("socket file doesn't exist");
  66     }else{
  67       perror("[tomd] socket unlink");
  68       exit(EXIT_FAILURE);
  69     }
  70   }
  71 }
  72
  73 static void socket_init(void)
  74 {
  75   gen_socket_filename();
  76
  77   /* listen on socket, respond to requests. */
  78   /* perform all registered 'tick' operations */
  79   sfd =
  80     socket(PF_LOCAL,         /* namespace - local unix socket */
  81            SOCK_STREAM,      /* style */
  82            0);               /* protocol */
  83
  84   if(sfd < 0){
  85     perror("[tomd] socket");
  86     exit(EXIT_FAILURE);
  87   }
  88
  89   struct sockaddr_un name;
  90   size_t size;
  91
  92   name.sun_family = AF_LOCAL;
  93   strncpy(name.sun_path,
  94           socket_filename,
  95           sizeof(name.sun_path));
  96
  97   size = SUN_LEN(&name);
  98   tomd_p("attempting to bind to '%s'",
  99          socket_filename);
 100   if(bind(sfd,
 101           (struct sockaddr *) &name,
 102           size) < 0){
 103     perror("[tomd] bind");
 104     exit(EXIT_FAILURE);
 105   }
 106
 107   tomd_p("initialized tomd socket connections");
 108 }
 109
 110 static void init(void)
 111 {
 112   socket_init();
 113   load_jobs();
 114 }
 115
 116 /* These defines are here to improve the local readability */
 117 #define CHDIR            0
 118 #define DONT_CHDIR       1
 119 #define CLOSE_PIPES      0
 120 #define DONT_CLOSE_PIPES 1
 121
 122 static void daemonize(void)
 123 {
 124   /* daemon is in unistd. */
 125   /* arg1 - 0 changes dir to / */
 126   /* arg2 - 0 closes all pipes (/dev/null) */
 127   /* WARNING > THIS BEHAVIOR IS SILENT AND EASY TO MISPLACE THE
 128      PROCESS  */
 129   daemon(DONT_CHDIR, DONT_CLOSE_PIPES);
 130 }
 131
 132 static void run(void)
 133 {
 134   /* loop: */
 135   /*  1 listen */
 136   /*  2 accept/select */
 137   /*  3 handle dgram */
 138   int listen_bool =
 139     listen(sfd,
 140            10); /* max connection limit is 10 for arbitrary reasons */
 141   if(listen_bool == -1){
 142     perror("[tomd] listen");
 143     exit(EXIT_FAILURE);
 144   }
 145
 146   for(;;){
 147     struct sockaddr addr;
 148     socklen_t size;
 149     int accept_sfd =
 150       accept(sfd,
 151              &addr,             /* requester info */
 152              &size);            /* len of requester info */
 153     if(accept_sfd < 0){
 154       perror("[tomd] accept socket");
 155       exit(EXIT_FAILURE);
 156     }
 157
 158     /* int getsockname(accept_sfd, */
 159     /*                 addr, */
 160     /*                 size); */
 161
 162     tomd_p("accepted socket connection from '%s'",
 163            ((struct sockaddr_un *) &addr)->sun_path);
 164
 165     char accept_buf[100] = {};
 166
 167     read(accept_sfd, accept_buf, 100);
 168     tomd_p("got message '%s', accept_buf");
 169     close(accept_sfd);
 170   }
 171 }
 172
 173 static void cleanup(void)
 174 {
 175   if(sfd >= 0){
 176     close(sfd);
 177   }
 178 }
 179
 180 int main(int argc, char **argv)
 181 {
 182   header();
 183   init();
 184   /* daemonize(); */
 185   /* run(); */
 186   cleanup();
 187
 188   return EXIT_SUCCESS;
 189 }