src/debug-generator/debug-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 2014 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 "util.h"
  23 #include "strv.h"
  24 #include "unit-name.h"
  25 #include "mkdir.h"
  26
  27 static const char *arg_dest = "/tmp";
  28 static char **arg_mask = NULL;
  29 static bool arg_debug_shell = false;
  30
  31 static int parse_proc_cmdline_item(const char *key, const char *value) {
  32         int r;
  33
  34         if (streq(key, "systemd.mask")) {
  35
  36                 if (!value)
  37                         log_error("Missing argument for systemd.mask= kernel command line parameter.");
  38                 else {
  39                         char *n;
  40
  41                         n = strdup(value);
  42                         if (!n)
  43                                 return log_oom();
  44
  45                         r = strv_consume(&arg_mask, n);
  46                         if (r < 0)
  47                                 return log_oom();
  48                 }
  49         } else if (streq(key, "systemd.debug-shell")) {
  50
  51                 if (value) {
  52                         r = parse_boolean(value);
  53                         if (r < 0)
  54                                 log_error("Failed to parse systemd.debug-shell= argument '%s', ignoring.", value);
  55                         else
  56                                 arg_debug_shell = r;
  57                 } else
  58                         arg_debug_shell = true;
  59         }
  60
  61         return 0;
  62 }
  63
  64 static int generate_mask_symlinks(void) {
  65         char **u;
  66         int r = 0;
  67
  68         if (strv_isempty(arg_mask))
  69                 return 0;
  70
  71         STRV_FOREACH(u, arg_mask) {
  72                 _cleanup_free_ char *m = NULL, *p = NULL;
  73
  74                 m = unit_name_mangle(*u, MANGLE_NOGLOB);
  75                 if (!m)
  76                         return log_oom();
  77
  78                 p = strjoin(arg_dest, "/", m, NULL);
  79                 if (!p)
  80                         return log_oom();
  81
  82                 if (symlink("/dev/null", p) < 0) {
  83                         log_error("Failed to create mask symlink %s: %m", p);
  84                         r = -errno;
  85                 }
  86         }
  87
  88         return r;
  89 }
  90
  91 static int generate_debug_shell_symlink(void) {
  92         const char *p;
  93
  94         if (!arg_debug_shell)
  95                 return 0;
  96
  97         p = strappenda(arg_dest, "/default.target.wants/debug-shell.service");
  98
  99         mkdir_parents_label(p, 0755);
 100
 101         if (symlink(SYSTEM_DATA_UNIT_PATH "/debug-shell.service", p) < 0) {
 102                 log_error("Failed to create %s symlink: %m", p);
 103                 return -errno;
 104         }
 105
 106         return 0;
 107 }
 108
 109 int main(int argc, char *argv[]) {
 110         int r, q;
 111
 112         if (argc > 1 && argc != 4) {
 113                 log_error("This program takes three or no arguments.");
 114                 return EXIT_FAILURE;
 115         }
 116
 117         if (argc > 1)
 118                 arg_dest = argv[2];
 119
 120         log_set_target(LOG_TARGET_SAFE);
 121         log_parse_environment();
 122         log_open();
 123
 124         umask(0022);
 125
 126         if (parse_proc_cmdline(parse_proc_cmdline_item) < 0)
 127                 return EXIT_FAILURE;
 128
 129         r = generate_mask_symlinks();
 130
 131         q = generate_debug_shell_symlink();
 132         if (q < 0)
 133                 r = q;
 134
 135         return r < 0 ? EXIT_FAILURE : EXIT_SUCCESS;
 136
 137 }