src/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 General Public License as published by
  10   the Free Software Foundation; either version 2 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   General Public License for more details.
  17
  18   You should have received a copy of the GNU 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 "unit-name.h"
  29 #include "virt.h"
  30
  31 const char *arg_dest = "/tmp";
  32
  33 static int add_symlink(const char *fservice, const char *tservice) {
  34         char *from = NULL, *to = NULL;
  35         int r;
  36
  37         assert(fservice);
  38         assert(tservice);
  39
  40         asprintf(&from, SYSTEM_DATA_UNIT_PATH "/%s", fservice);
  41         asprintf(&to, "%s/getty.target.wants/%s", arg_dest, tservice);
  42
  43         if (!from || !to) {
  44                 log_error("Out of memory");
  45                 r = -ENOMEM;
  46                 goto finish;
  47         }
  48
  49         mkdir_parents(to, 0755);
  50
  51         r = symlink(from, to);
  52         if (r < 0) {
  53                 if (errno == EEXIST)
  54                         /* In case console=hvc0 is passed this will very likely result in EEXIST */
  55                         r = 0;
  56                 else {
  57                         log_error("Failed to create symlink from %s to %s: %m", from, to);
  58                         r = -errno;
  59                 }
  60         }
  61
  62 finish:
  63
  64         free(from);
  65         free(to);
  66
  67         return r;
  68 }
  69
  70 static int add_serial_getty(const char *tty) {
  71         char *n;
  72         int r;
  73
  74         assert(tty);
  75
  76         log_debug("Automatically adding serial getty for /dev/%s.", tty);
  77
  78         n = unit_name_replace_instance("serial-getty@.service", tty);
  79         if (!n) {
  80                 log_error("Out of memory");
  81                 return -ENOMEM;
  82         }
  83
  84         r = add_symlink("serial-getty@.service", n);
  85         free(n);
  86
  87         return r;
  88 }
  89
  90 int main(int argc, char *argv[]) {
  91
  92         static const char virtualization_consoles[] =
  93                 "hvc0\0"
  94                 "xvc0\0"
  95                 "hvsi0\0";
  96
  97         int r = EXIT_SUCCESS;
  98         char *active;
  99         const char *j;
 100
 101         if (argc > 2) {
 102                 log_error("This program takes one or no arguments.");
 103                 return EXIT_FAILURE;
 104         }
 105
 106         log_set_target(LOG_TARGET_SYSLOG_OR_KMSG);
 107         log_parse_environment();
 108         log_open();
 109
 110         umask(0022);
 111
 112         if (argc > 1)
 113             arg_dest = argv[1];
 114
 115         if (detect_container(NULL) > 0) {
 116                 log_debug("Automatically adding console shell.");
 117
 118                 if (add_symlink("console-shell.service", "console-shell.service") < 0)
 119                         r = EXIT_FAILURE;
 120
 121                 /* Don't add any further magic if we are in a container */
 122                 goto finish;
 123         }
 124
 125         if (read_one_line_file("/sys/class/tty/console/active", &active) >= 0) {
 126                 const char *tty;
 127
 128                 tty = strrchr(active, ' ');
 129                 if (tty)
 130                         tty ++;
 131                 else
 132                         tty = active;
 133
 134                 /* Automatically add in a serial getty on the kernel
 135                  * console */
 136                 if (tty_is_vc(tty))
 137                         free(active);
 138                 else {
 139                         int k;
 140
 141                         /* We assume that gettys on virtual terminals are
 142                          * started via manual configuration and do this magic
 143                          * only for non-VC terminals. */
 144
 145                         k = add_serial_getty(tty);
 146                         free(active);
 147
 148                         if (k < 0) {
 149                                 r = EXIT_FAILURE;
 150                                 goto finish;
 151                         }
 152                 }
 153         }
 154
 155         /* Automatically add in a serial getty on the first
 156          * virtualizer console */
 157         NULSTR_FOREACH(j, virtualization_consoles) {
 158                 char *p;
 159                 int k;
 160
 161                 if (asprintf(&p, "/sys/class/tty/%s", j) < 0) {
 162                         log_error("Out of memory");
 163                         r = EXIT_FAILURE;
 164                         goto finish;
 165                 }
 166
 167                 k = access(p, F_OK);
 168                 free(p);
 169
 170                 if (k < 0)
 171                         continue;
 172
 173                 k = add_serial_getty(j);
 174                 if (k < 0) {
 175                         r = EXIT_FAILURE;
 176                         goto finish;
 177                 }
 178         }
 179
 180 finish:
 181         return r;
 182 }