src/ttyinit.c

   1 #include <sys/time.h>
   2 #include <sys/resource.h>
   3
   4 //#define K8STERM_DEBUG_EXEC
   5
   6
   7 ////////////////////////////////////////////////////////////////////////////////
   8 // tty init
   9 /*
  10 static void dump (char c) {
  11   static int col;
  12   //
  13   fprintf(stderr, " %02x '%c' ", c, isprint(c)?c:'.');
  14   if (++col % 10 == 0) fprintf(stderr, "\n");
  15 }
  16 */
  17
  18 typedef struct {
  19   char **args;
  20   int argc;
  21 } ExecData;
  22
  23
  24 static void execsh_free (ExecData *ed) {
  25   if (!ed) return;
  26   if (ed->args) {
  27     for (int f = 0; f < ed->argc; ++f) free(ed->args[f]);
  28     free(ed->args);
  29   }
  30   memset(ed, 0, sizeof(*ed));
  31 }
  32
  33
  34 static int execsh_prepare (ExecData *ed, const char *str) {
  35   if (!ed) return -1;
  36   #ifdef K8STERM_DEBUG_EXEC
  37   FILE *fo = stderr; //fopen("/tmp/z_k8sterm_exec_debug.log", "w");
  38   #endif
  39
  40   memset(ed, 0, sizeof(*ed));
  41   char **args;
  42   int argc;
  43   if (str == NULL) {
  44     char *envshell = getenv("SHELL");
  45     if (envshell == NULL) envshell = "/bin/sh";
  46     K8T_DEFAULT(envshell, opt_shell);
  47     setenv("TERM", opt_term, 1);
  48     //args = (opt_cmd ? opt_cmd : (char *[]){envshell, "-i", NULL});
  49     if (opt_cmd && opt_cmd_count > 0) {
  50       #ifdef K8STERM_DEBUG_EXEC
  51       if (fo) fprintf(fo, "EXECSH: executing `opt_cmd` (%d): <%s>\n", opt_cmd_count, opt_cmd[0]);
  52       #endif
  53       args = calloc(opt_cmd_count+1, sizeof(char*));
  54       if (!args) return -1;
  55       argc = opt_cmd_count;
  56       for (int f = 0; f < opt_cmd_count; ++f) {
  57         #ifdef K8STERM_DEBUG_EXEC
  58         if (fo) fprintf(fo, "EXECSH:   arg #%d of %d: <%s>\n", f, opt_cmd_count, opt_cmd[f]);
  59         #endif
  60         args[f] = strdup(opt_cmd[f]);
  61         if (!args[f]) {
  62           for (int c = 0; c < f; ++c) free(args[c]);
  63           free(args);
  64           return -1;
  65         }
  66       }
  67       args[argc] = NULL;
  68     } else {
  69       args = calloc(3, sizeof(char*));
  70       if (!args) return -1;
  71       #ifdef K8STERM_DEBUG_EXEC
  72       if (fo) fprintf(fo, "EXECSH: executing `opt_cmd` shell: <%s>\n", envshell);
  73       #endif
  74       argc = 2;
  75       args[0] = strdup(envshell);
  76       if (!args[0]) { free(args); return -1; }
  77       args[1] = strdup("-i");
  78       if (!args[1]) { free(args[0]); free(args); return -1; }
  79       args[2] = NULL;
  80     }
  81   } else {
  82     #ifdef K8STERM_DEBUG_EXEC
  83     if (fo) fprintf(fo, "EXECSH: executing `str`: <%s>\n", str);
  84     #endif
  85     argc = 0;
  86     args = calloc(32768, sizeof(char *));
  87     if (args == NULL) return -1;
  88     while (*str) {
  89       if (argc >= 32766) break;
  90       const char *b;
  91       while (*str && isspace(*str)) ++str;
  92       if (!str[0]) break;
  93       b = str;
  94       while (*str && !isspace(*str)) {
  95         if (*str++ == '\\') {
  96           if (*str) ++str;
  97         }
  98       }
  99       args[argc] = calloc(str-b+1, 1);
 100       if (!args[argc]) {
 101         for (int f = 0; f < argc; ++f) free(args[f]);
 102         free(args);
 103         return -1;
 104       }
 105       memcpy(args[argc], b, str-b);
 106       #ifdef K8STERM_DEBUG_EXEC
 107       if (fo) fprintf(fo, "EXECSH:   argc=%d; argv=<%s>\n", argc, args[argc]);
 108       #endif
 109       ++argc;
 110     }
 111     args[argc] = NULL;
 112   }
 113   #ifdef K8STERM_DEBUG_EXEC
 114   if (fo && fo != stdout && fo != stderr) fclose(fo);
 115   #endif
 116
 117   ed->args = args;
 118   ed->argc = argc;
 119   if (argc < 1) { execsh_free(ed); return -1; }
 120   return 0;
 121 }
 122
 123
 124 static __attribute__((noreturn)) void execsh (ExecData *ed) {
 125   if (!ed) exit(EXIT_FAILURE);
 126   if (ed->argc == 0) exit(EXIT_FAILURE);
 127   /*
 128   {
 129     extern char **environ;
 130     FILE *fo = fopen("z.log", "a");
 131     for (char **e = environ; *e; ++e) {
 132       fprintf(fo, "[%s]\n", *e);
 133     }
 134     fclose(fo);
 135   }
 136   */
 137   // close FDs
 138   {
 139     struct rlimit r;
 140     getrlimit(RLIMIT_NOFILE, &r);
 141     for (rlim_t f = 3; f < r.rlim_cur; ++f) close(f);
 142   }
 143   execvp(ed->args[0], ed->args);
 144   exit(EXIT_FAILURE);
 145 }
 146
 147
 148 static int k8t_ttyNew (K8Term *term) {
 149   int masterfd = -1;
 150   struct winsize w = {term->row, term->col, 0, 0};
 151   ExecData ed;
 152   if (execsh_prepare(&ed, K8T_DATA(term)->execcmd) != 0) {
 153     fprintf(stderr, "EXEC <%s> failed!\n", K8T_DATA(term)->execcmd);
 154     return -1;
 155   }
 156   switch (K8T_DATA(term)->pid = forkpty(&masterfd, NULL, NULL, &w)) {
 157     case -1: /* error */
 158       execsh_free(&ed);
 159       fprintf(stderr, "fork failed");
 160       if (masterfd != -1) close(masterfd);
 161       return -1;
 162     case 0: /* child */
 163       setsid(); /* create a new process group */
 164       execsh(&ed);
 165       break;
 166     default: /* master */
 167       execsh_free(&ed);
 168       term->cmdfd = masterfd;
 169       term->dead = 0;
 170       k8t_ttyResize(term);
 171       break;
 172   }
 173   return 0;
 174 }
 175
 176 #if 0
 177 static int k8t_ttyNew (K8Term *term) {
 178   int m, s;
 179   struct winsize w = {term->row, term->col, 0, 0};
 180   //
 181   if (openpty(&m, &s, NULL, NULL, &w) < 0) k8t_die("openpty failed: %s", strerror(errno));
 182   term->cmdfd = m;
 183   k8t_ttyResize(term);
 184   term->cmdfd = -1;
 185   switch (K8T_DATA(term)->pid = fork()) {
 186     case -1: /* error */
 187       fprintf(stderr, "fork failed");
 188       return -1;
 189     case 0: /* child */
 190       setsid(); /* create a new process group */
 191       dup2(s, STDIN_FILENO);
 192       dup2(s, STDOUT_FILENO);
 193       dup2(s, STDERR_FILENO);
 194       if (ioctl(s, TIOCSCTTY, NULL) < 0) k8t_die("ioctl TIOCSCTTY failed: %s", strerror(errno));
 195       close(s);
 196       close(m);
 197       execsh(K8T_DATA(term)->execcmd);
 198       break;
 199     default: /* master */
 200       close(s);
 201       term->cmdfd = m;
 202       term->dead = 0;
 203       k8t_ttyResize(term);
 204       break;
 205   }
 206   return 0;
 207 }
 208 #endif