src/debug-generator/debug-generator.c

   1 /* SPDX-License-Identifier: LGPL-2.1+ */
   2 /***
   3   This file is part of systemd.
   4
   5   Copyright 2014 Lennart Poettering
   6 ***/
   7
   8 #include "alloc-util.h"
   9 #include "mkdir.h"
  10 #include "parse-util.h"
  11 #include "proc-cmdline.h"
  12 #include "special.h"
  13 #include "string-util.h"
  14 #include "strv.h"
  15 #include "unit-name.h"
  16 #include "util.h"
  17
  18 static char *arg_default_unit = NULL;
  19 static const char *arg_dest = "/tmp";
  20 static char **arg_mask = NULL;
  21 static char **arg_wants = NULL;
  22 static bool arg_debug_shell = false;
  23
  24 static int parse_proc_cmdline_item(const char *key, const char *value, void *data) {
  25         int r;
  26
  27         assert(key);
  28
  29         if (streq(key, "systemd.mask")) {
  30                 char *n;
  31
  32                 if (proc_cmdline_value_missing(key, value))
  33                         return 0;
  34
  35                 r = unit_name_mangle(value, UNIT_NAME_MANGLE_WARN, &n);
  36                 if (r < 0)
  37                         return log_error_errno(r, "Failed to glob unit name: %m");
  38
  39                 r = strv_consume(&arg_mask, n);
  40                 if (r < 0)
  41                         return log_oom();
  42
  43         } else if (streq(key, "systemd.wants")) {
  44                 char *n;
  45
  46                 if (proc_cmdline_value_missing(key, value))
  47                         return 0;
  48
  49                 r = unit_name_mangle(value, UNIT_NAME_MANGLE_WARN, &n);
  50                 if (r < 0)
  51                         return log_error_errno(r, "Failed to glob unit name: %m");
  52
  53                 r = strv_consume(&arg_wants, n);
  54                 if (r < 0)
  55                         return log_oom();
  56
  57         } else if (proc_cmdline_key_streq(key, "systemd.debug_shell")) {
  58
  59                 if (value) {
  60                         r = parse_boolean(value);
  61                         if (r < 0)
  62                                 log_error("Failed to parse systemd.debug_shell= argument '%s', ignoring.", value);
  63                         else
  64                                 arg_debug_shell = r;
  65                 } else
  66                         arg_debug_shell = true;
  67
  68         } else if (streq(key, "systemd.unit")) {
  69
  70                 if (proc_cmdline_value_missing(key, value))
  71                         return 0;
  72
  73                 r = free_and_strdup(&arg_default_unit, value);
  74                 if (r < 0)
  75                         return log_error_errno(r, "Failed to set default unit %s: %m", value);
  76
  77         } else if (!value) {
  78                 const char *target;
  79
  80                 target = runlevel_to_target(key);
  81                 if (target) {
  82                         r = free_and_strdup(&arg_default_unit, target);
  83                         if (r < 0)
  84                                 return log_error_errno(r, "Failed to set default unit %s: %m", target);
  85                 }
  86         }
  87
  88         return 0;
  89 }
  90
  91 static int generate_mask_symlinks(void) {
  92         char **u;
  93         int r = 0;
  94
  95         if (strv_isempty(arg_mask))
  96                 return 0;
  97
  98         STRV_FOREACH(u, arg_mask) {
  99                 _cleanup_free_ char *p = NULL;
 100
 101                 p = strjoin(arg_dest, "/", *u);
 102                 if (!p)
 103                         return log_oom();
 104
 105                 if (symlink("/dev/null", p) < 0)
 106                         r = log_error_errno(errno,
 107                                             "Failed to create mask symlink %s: %m",
 108                                             p);
 109         }
 110
 111         return r;
 112 }
 113
 114 static int generate_wants_symlinks(void) {
 115         char **u;
 116         int r = 0;
 117
 118         if (strv_isempty(arg_wants))
 119                 return 0;
 120
 121         STRV_FOREACH(u, arg_wants) {
 122                 _cleanup_free_ char *p = NULL, *f = NULL;
 123                 const char *target = arg_default_unit ?: SPECIAL_DEFAULT_TARGET;
 124
 125                 p = strjoin(arg_dest, "/", target, ".wants/", *u);
 126                 if (!p)
 127                         return log_oom();
 128
 129                 f = strappend(SYSTEM_DATA_UNIT_PATH "/", *u);
 130                 if (!f)
 131                         return log_oom();
 132
 133                 mkdir_parents_label(p, 0755);
 134
 135                 if (symlink(f, p) < 0)
 136                         r = log_error_errno(errno,
 137                                             "Failed to create wants symlink %s: %m",
 138                                             p);
 139         }
 140
 141         return r;
 142 }
 143
 144 int main(int argc, char *argv[]) {
 145         int r, q;
 146
 147         if (argc > 1 && argc != 4) {
 148                 log_error("This program takes three or no arguments.");
 149                 return EXIT_FAILURE;
 150         }
 151
 152         if (argc > 1)
 153                 arg_dest = argv[2];
 154
 155         log_set_prohibit_ipc(true);
 156         log_set_target(LOG_TARGET_AUTO);
 157         log_parse_environment();
 158         log_open();
 159
 160         umask(0022);
 161
 162         r = proc_cmdline_parse(parse_proc_cmdline_item, NULL, 0);
 163         if (r < 0)
 164                 log_warning_errno(r, "Failed to parse kernel command line, ignoring: %m");
 165
 166         if (arg_debug_shell) {
 167                 r = strv_extend(&arg_wants, "debug-shell.service");
 168                 if (r < 0) {
 169                         r = log_oom();
 170                         goto finish;
 171                 }
 172         }
 173
 174         r = generate_mask_symlinks();
 175
 176         q = generate_wants_symlinks();
 177         if (q < 0)
 178                 r = q;
 179
 180 finish:
 181         arg_default_unit = mfree(arg_default_unit);
 182
 183         return r < 0 ? EXIT_FAILURE : EXIT_SUCCESS;
 184 }