src/getty-generator/getty-generator.c

   1 /*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
   2
   3 /***
   4   This file is part of systemd.
   5
   6   Copyright 2010 Lennart Poettering
   7
   8   systemd is free software; you can redistribute it and/or modify it
   9   under the terms of the GNU Lesser General Public License as published by
  10   the Free Software Foundation; either version 2.1 of the License, or
  11   (at your option) any later version.
  12
  13   systemd is distributed in the hope that it will be useful, but
  14   WITHOUT ANY WARRANTY; without even the implied warranty of
  15   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  16   Lesser General Public License for more details.
  17
  18   You should have received a copy of the GNU Lesser General Public License
  19   along with systemd; If not, see <http://www.gnu.org/licenses/>.
  20 ***/
  21
  22 #include <string.h>
  23 #include <errno.h>
  24 #include <unistd.h>
  25
  26 #include "log.h"
  27 #include "util.h"
  28 #include "mkdir.h"
  29 #include "unit-name.h"
  30 #include "virt.h"
  31
  32 static const char *arg_dest = "/tmp";
  33
  34 static int add_symlink(const char *fservice, const char *tservice) {
  35         char *from = NULL, *to = NULL;
  36         int r;
  37
  38         assert(fservice);
  39         assert(tservice);
  40
  41         from = strappend(SYSTEM_DATA_UNIT_PATH "/", fservice);
  42         to = join(arg_dest,"/getty.target.wants/", tservice, NULL);
  43
  44         if (!from || !to) {
  45                 log_error("Out of memory");
  46                 r = -ENOMEM;
  47                 goto finish;
  48         }
  49
  50         mkdir_parents_label(to, 0755);
  51
  52         r = symlink(from, to);
  53         if (r < 0) {
  54                 if (errno == EEXIST)
  55                         /* In case console=hvc0 is passed this will very likely result in EEXIST */
  56                         r = 0;
  57                 else {
  58                         log_error("Failed to create symlink from %s to %s: %m", from, to);
  59                         r = -errno;
  60                 }
  61         }
  62
  63 finish:
  64
  65         free(from);
  66         free(to);
  67
  68         return r;
  69 }
  70
  71 static int add_serial_getty(const char *tty) {
  72         char *n;
  73         int r;
  74
  75         assert(tty);
  76
  77         log_debug("Automatically adding serial getty for /dev/%s.", tty);
  78
  79         n = unit_name_replace_instance("serial-getty@.service", tty);
  80         if (!n) {
  81                 log_error("Out of memory");
  82                 return -ENOMEM;
  83         }
  84
  85         r = add_symlink("serial-getty@.service", n);
  86         free(n);
  87
  88         return r;
  89 }
  90
  91 int main(int argc, char *argv[]) {
  92
  93         static const char virtualization_consoles[] =
  94                 "hvc0\0"
  95                 "xvc0\0"
  96                 "hvsi0\0";
  97
  98         int r = EXIT_SUCCESS;
  99         char *active;
 100         const char *j;
 101
 102         if (argc > 1 && argc != 4) {
 103                 log_error("This program takes three or no arguments.");
 104                 return EXIT_FAILURE;
 105         }
 106
 107         if (argc > 1)
 108                 arg_dest = argv[1];
 109
 110         log_set_target(LOG_TARGET_SAFE);
 111         log_parse_environment();
 112         log_open();
 113
 114         umask(0022);
 115
 116         if (detect_container(NULL) > 0) {
 117                 log_debug("Automatically adding console shell.");
 118
 119                 if (add_symlink("console-getty.service", "console-getty.service") < 0)
 120                         r = EXIT_FAILURE;
 121
 122                 /* Don't add any further magic if we are in a container */
 123                 goto finish;
 124         }
 125
 126         if (read_one_line_file("/sys/class/tty/console/active", &active) >= 0) {
 127                 const char *tty;
 128
 129                 tty = strrchr(active, ' ');
 130                 if (tty)
 131                         tty ++;
 132                 else
 133                         tty = active;
 134
 135                 /* Automatically add in a serial getty on the kernel
 136                  * console */
 137                 if (tty_is_vc(tty))
 138                         free(active);
 139                 else {
 140                         int k;
 141
 142                         /* We assume that gettys on virtual terminals are
 143                          * started via manual configuration and do this magic
 144                          * only for non-VC terminals. */
 145
 146                         k = add_serial_getty(tty);
 147                         free(active);
 148
 149                         if (k < 0) {
 150                                 r = EXIT_FAILURE;
 151                                 goto finish;
 152                         }
 153                 }
 154         }
 155
 156         /* Automatically add in a serial getty on the first
 157          * virtualizer console */
 158         NULSTR_FOREACH(j, virtualization_consoles) {
 159                 char *p;
 160                 int k;
 161
 162                 if (asprintf(&p, "/sys/class/tty/%s", j) < 0) {
 163                         log_error("Out of memory");
 164                         r = EXIT_FAILURE;
 165                         goto finish;
 166                 }
 167
 168                 k = access(p, F_OK);
 169                 free(p);
 170
 171                 if (k < 0)
 172                         continue;
 173
 174                 k = add_serial_getty(j);
 175                 if (k < 0) {
 176                         r = EXIT_FAILURE;
 177                         goto finish;
 178                 }
 179         }
 180
 181 finish:
 182         return r;
 183 }