src/slave.c

   1 #define _XOPEN_SOURCE 700
   2 #define _GNU_SOURCE
   3
   4
   5
   6 #include "slave.h"
   7 #include <assert.h>
   8
   9 #include "network.h"
  10 #include "daemon.h"
  11 #include "log.h"
  12 #include <errno.h>
  13 #include <pty.h>
  14 #include <fcntl.h>
  15 #include <string.h>
  16
  17 #include <pthread.h>
  18 #include <syslog.h>
  19 #include <signal.h>
  20 #include <unistd.h>
  21 #include <sys/types.h>
  22 #include <sys/wait.h>
  23 #include <sys/socket.h>
  24 #include <netinet/tcp.h>
  25
  26
  27
  28 Slave * slave;
  29
  30 char name[BUFSIZ];
  31
  32 void Slave_shell(int i, char * shell);
  33 void Slave_cleanup();
  34
  35
  36 void Slave_main(Options * o)
  37 {
  38
  39
  40         setbuf(stdin, NULL); setbuf(stdout, NULL); setbuf(stderr, NULL);
  41
  42         dup2(fileno(stdout), fileno(stderr)); // yes, this works, apparently
  43
  44         slave = (Slave*)(calloc(o->nCPU, sizeof(slave)));
  45         atexit(Slave_cleanup);
  46
  47
  48         if (strcmp(o->master_addr, "-") != 0)
  49         {
  50                 if (fork() != 0)
  51                         exit(EXIT_SUCCESS);
  52
  53                 //log_print(2, "Slave_main", "Using unsecured networking; connect to %s:%d", o->master_addr, o->port);
  54                 //log_print(2, "Slave_main", "Connecting to %s:%d", o->master_addr, o->port);
  55                 int net_fd = Network_client(o->master_addr, o->port, 100);
  56                 dup2(net_fd, fileno(stdin));
  57                 dup2(net_fd, fileno(stdout));
  58                 dup2(net_fd, fileno(stderr));
  59
  60         }
  61         else
  62         {
  63                 o->master_addr = "localhost";
  64                 //log_print(2, "Slave_main", "Using port forwarding; connect to %s", o->master_addr);
  65         }
  66
  67         char buffer[BUFSIZ];
  68
  69         fgets(name, sizeof(name), stdin);
  70         name[strlen(name)-1] = '\0';
  71         //log_print(2, "Slave_main", "Got name %s", name);
  72
  73         fprintf(stdout, "%d\n", o->nCPU);
  74         //log_print(2, "Slave_main", "Wrote nCPU %d", o->nCPU);
  75
  76
  77         int port = 0;
  78         for (int i = 0; i < o->nCPU; ++i)
  79         {
  80                 //log_print(2, "Slave_main", "Waiting for port number...");
  81                 fgets(buffer, sizeof(buffer), stdin);
  82
  83                 buffer[strlen(buffer)-1] = '\0';
  84                 sscanf(buffer, "%d", &port);
  85                 //log_print(2, "Slave_main", "Port number %d", port);
  86                 slave[i].in = Network_client(o->master_addr, port,20);
  87                 //log_print(2, "Slave_main", "Connected to %s:%d\n", o->master_addr, port);
  88                 slave[i].out = slave[i].in;
  89
  90                 Slave_shell(i, o->shell);
  91         }
  92
  93
  94         Slave_loop(o);
  95
  96         exit(EXIT_SUCCESS);
  97 }
  98
  99 void Slave_shell(int i, char * shell)
 100 {
 101         slave[i].pid = fork();
 102
 103
 104
 105         if (slave[i].pid == 0)
 106         {
 107                 dup2(slave[i].in, fileno(stdin));
 108                 dup2(slave[i].out, fileno(stdout));
 109                 //dup2(error_socket[1], fileno(stderr));
 110
 111                 execlp(shell, shell, NULL);
 112         }
 113
 114         // if the input is a network socket, this message gets sent to the master
 115         // which will then echo it back to the socket and hence the shell
 116         FILE * f = fdopen(slave[i].in, "w"); setbuf(f, NULL);
 117         fprintf(f, "name=\"%s:%d\"\n", name,i);
 118 }
 119
 120 void Slave_loop(Options * o)
 121 {
 122         fd_set readSet;
 123         struct timeval tv;
 124         tv.tv_sec = 0;
 125         tv.tv_usec = 100000;
 126
 127         int p = -1; int s = 0;
 128         char buffer[BUFSIZ];
 129         while (true)
 130         {
 131                 FD_ZERO(&readSet);
 132                 FD_SET(fileno(stdin), &readSet);
 133                 p = waitpid(-1, &s, 0);
 134                 if (p == -1)
 135                 {
 136                         //log_print(0, "Slave_loop", "waitpid : %s", strerror(errno));
 137                         continue;
 138                 }
 139
 140                 //log_print(3, "Slave_loop", "Detected child %d exiting...", p);
 141
 142                 // check for an exit command from the master
 143                 select(fileno(stdin) + 1, &readSet, NULL, NULL, &tv);
 144
 145                 if (FD_ISSET(fileno(stdin), &readSet))
 146                 {
 147                         fgets(buffer, sizeof(buffer), stdin);
 148                         if (strcmp(buffer, "exit\n") == 0)
 149                         {
 150                                 log_print(2, "Slave_loop", "Received notification of exit.\n");
 151                                 exit(EXIT_SUCCESS);
 152                         }
 153                 }
 154
 155                 int i = 0;
 156                 for (i = 0; i < o->nCPU; ++i)
 157                 {
 158                         if (slave[i].pid == p) break;
 159                 }
 160                 if (i >= o->nCPU)
 161                         error("Slave_loop", "No child matches pid %d", p);
 162
 163
 164
 165                 fprintf(stderr,"Unexpected exit of slave %s:%d", name, i);
 166                 if (WIFSIGNALED(s))
 167                 {
 168                         int sig = WTERMSIG(s);
 169                         fprintf(stderr," due to %s", strsignal(sig));
 170                         if (sig == SIGKILL)
 171                         {
 172                                 fprintf(stderr," - %s committing suicide\n", name);
 173                                 kill(getpid(), sig);
 174                         }
 175                 }
 176                 else
 177                 {
 178                         fprintf(stderr," return code %d.", s);
 179                 }
 180
 181
 182                 // cancel any tasks at the master for this slave
 183                 static int len = -1;
 184                 if (len < 0)
 185                         len = strlen(o->end);
 186                 write(slave[i].out, o->end, len);
 187
 188                 Slave_shell(i, o->shell);
 189
 190
 191         }
 192 }
 193
 194 void Slave_cleanup()
 195 {
 196         for (int i = 0; i < options.nCPU; ++i)
 197         {
 198                 kill(slave[i].pid, SIGTERM);
 199         }
 200         sleep(1);
 201         for (int i = 0; i < options.nCPU; ++i)
 202         {
 203                 kill(slave[i].pid, SIGKILL);
 204         }
 205         free(slave);
 206 }
 207
 208