src/condition.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 <stdlib.h>
  23 #include <errno.h>
  24 #include <string.h>
  25 #include <unistd.h>
  26
  27 #include "util.h"
  28 #include "condition.h"
  29
  30 Condition* condition_new(ConditionType type, const char *parameter, bool negate) {
  31         Condition *c;
  32
  33         c = new0(Condition, 1);
  34         c->type = type;
  35         c->negate = negate;
  36
  37         if (parameter)
  38                 if (!(c->parameter = strdup(parameter))) {
  39                         free(c);
  40                         return NULL;
  41                 }
  42
  43         return c;
  44 }
  45
  46 void condition_free(Condition *c) {
  47         assert(c);
  48
  49         free(c->parameter);
  50         free(c);
  51 }
  52
  53 void condition_free_list(Condition *first) {
  54         Condition *c, *n;
  55
  56         LIST_FOREACH_SAFE(conditions, c, n, first)
  57                 condition_free(c);
  58 }
  59
  60 static bool test_kernel_command_line(const char *parameter) {
  61         char *line, *w, *state, *word = NULL;
  62         bool equal;
  63         int r;
  64         size_t l, pl;
  65         bool found = false;
  66
  67         assert(parameter);
  68
  69         if ((r = read_one_line_file("/proc/cmdline", &line)) < 0) {
  70                 log_warning("Failed to read /proc/cmdline, ignoring: %s", strerror(-r));
  71                 return false;
  72         }
  73
  74         equal = !!strchr(parameter, '=');
  75         pl = strlen(parameter);
  76
  77         FOREACH_WORD_QUOTED(w, l, line, state) {
  78
  79                 free(word);
  80                 if (!(word = strndup(w, l)))
  81                         break;
  82
  83                 if (equal) {
  84                         if (streq(word, parameter)) {
  85                                 found = true;
  86                                 break;
  87                         }
  88                 } else {
  89                         if (startswith(word, parameter) && (word[pl] == '=' || word[pl] == 0)) {
  90                                 found = true;
  91                                 break;
  92                         }
  93                 }
  94
  95         }
  96
  97         free(word);
  98         free(line);
  99
 100         return found;
 101 }
 102
 103 static bool test_virtualization(const char *parameter) {
 104         int r, b;
 105         const char *id;
 106
 107         assert(parameter);
 108
 109         if ((r = detect_virtualization(&id)) < 0) {
 110                 log_warning("Failed to detect virtualization, ignoring: %s", strerror(-r));
 111                 return false;
 112         }
 113
 114         b = parse_boolean(parameter);
 115
 116         if (r > 0 && b > 0)
 117                 return true;
 118
 119         if (r == 0 && b == 0)
 120                 return true;
 121
 122         return streq(parameter, id);
 123 }
 124
 125 bool condition_test(Condition *c) {
 126         assert(c);
 127
 128         switch(c->type) {
 129
 130         case CONDITION_PATH_EXISTS:
 131                 return (access(c->parameter, F_OK) >= 0) == !c->negate;
 132
 133         case CONDITION_DIRECTORY_NOT_EMPTY: {
 134                 int k;
 135
 136                 k = dir_is_empty(c->parameter);
 137                 return !(k == -ENOENT || k > 0) == !c->negate;
 138         }
 139
 140         case CONDITION_KERNEL_COMMAND_LINE:
 141                 return test_kernel_command_line(c->parameter) == !c->negate;
 142
 143         case CONDITION_VIRTUALIZATION:
 144                 return test_virtualization(c->parameter) == !c->negate;
 145
 146         case CONDITION_NULL:
 147                 return !c->negate;
 148
 149         default:
 150                 assert_not_reached("Invalid condition type.");
 151         }
 152 }
 153
 154 bool condition_test_list(Condition *first) {
 155         Condition *c;
 156
 157         /* If the condition list is empty, then it is true */
 158         if (!first)
 159                 return true;
 160
 161         /* Otherwise, if any of the conditions apply we return true */
 162         LIST_FOREACH(conditions, c, first)
 163                 if (condition_test(c))
 164                         return true;
 165
 166         return false;
 167 }
 168
 169 void condition_dump(Condition *c, FILE *f, const char *prefix) {
 170         assert(c);
 171         assert(f);
 172
 173         if (!prefix)
 174                 prefix = "";
 175
 176         fprintf(f,
 177                 "%s%s: %s%s\n",
 178                 prefix,
 179                 condition_type_to_string(c->type),
 180                 c->negate ? "!" : "",
 181                 c->parameter);
 182 }
 183
 184 void condition_dump_list(Condition *first, FILE *f, const char *prefix) {
 185         Condition *c;
 186
 187         LIST_FOREACH(conditions, c, first)
 188                 condition_dump(c, f, prefix);
 189 }
 190
 191 static const char* const condition_type_table[_CONDITION_TYPE_MAX] = {
 192         [CONDITION_KERNEL_COMMAND_LINE] = "ConditionKernelCommandLine",
 193         [CONDITION_PATH_EXISTS] = "ConditionPathExists",
 194         [CONDITION_NULL] = "ConditionNull"
 195 };
 196
 197 DEFINE_STRING_TABLE_LOOKUP(condition_type, ConditionType);