git.ozlabs.org Git - petitboot/blob - discover/grub2/script.c

   1
   2 #include <sys/types.h>
   3 #include <string.h>
   4
   5 #include <talloc/talloc.h>
   6
   7 #include "grub2.h"
   8
   9 #define to_stmt_simple(stmt) \
  10         container_of(stmt, struct grub2_statement_simple, st)
  11 #define to_stmt_if(stmt) \
  12         container_of(stmt, struct grub2_statement_if, st)
  13 #define to_stmt_menuentry(stmt) \
  14         container_of(stmt, struct grub2_statement_menuentry, st)
  15
  16 struct env_entry {
  17         const char              *name;
  18         const char              *value;
  19         struct list_item        list;
  20 };
  21
  22 const char *script_env_get(struct grub2_script *script, const char *name)
  23 {
  24         struct env_entry *entry;
  25
  26         list_for_each_entry(&script->environment, entry, list)
  27                 if (!strcmp(entry->name, name))
  28                         return entry->value;
  29
  30         return NULL;
  31 }
  32
  33 void script_env_set(struct grub2_script *script,
  34                 const char *name, const char *value)
  35 {
  36         struct env_entry *e, *entry = NULL;
  37
  38         list_for_each_entry(&script->environment, e, list) {
  39                 if (!strcmp(e->name, name)) {
  40                         entry = e;
  41                         break;
  42                 }
  43         }
  44
  45         if (!entry) {
  46                 entry = talloc(script, struct env_entry);
  47                 entry->name = name;
  48                 list_add(&script->environment, &entry->list);
  49         }
  50
  51         entry->value = value;
  52 }
  53
  54 static bool expand_var(struct grub2_script *script, struct grub2_word *word)
  55 {
  56         const char *val;
  57
  58         val = script_env_get(script, word->var.name);
  59         if (!val)
  60                 val = "";
  61
  62         word->type = GRUB2_WORD_TEXT;
  63         word->text = talloc_strdup(script, val);
  64
  65         return true;
  66 }
  67
  68 /* iterate through the words in an argv_list, looking for GRUB2_WORD_VAR
  69  * expansions.
  70  *
  71  * Once that's done, we may (if split == true) have to split the word to create
  72  * new argv items
  73  */
  74 static void process_expansions(struct grub2_script *script,
  75                 struct grub2_argv *argv)
  76 {
  77         struct grub2_word *top_word, *word;
  78         int i;
  79
  80         argv->argc = 0;
  81
  82         list_for_each_entry(&argv->words, top_word, argv_list) {
  83                 argv->argc++;
  84
  85                 /* expand vars and squash the list of words into the top struct.
  86                  * todo: splitting
  87                  */
  88                 for (word = top_word; word; word = word->next) {
  89                         if (word->type == GRUB2_WORD_VAR)
  90                                 expand_var(script, word);
  91
  92                         if (word == top_word)
  93                                 continue;
  94
  95                         top_word->text = talloc_asprintf_append(top_word->text,
  96                                         "%s", word->text);
  97                 }
  98                 top_word->next = NULL;
  99         }
 100
 101         argv->argv = talloc_array(script, char *, argv->argc);
 102         i = 0;
 103
 104         list_for_each_entry(&argv->words, word, argv_list)
 105                 argv->argv[i++] = word->text;
 106 }
 107
 108 int statements_execute(struct grub2_script *script,
 109                 struct grub2_statements *stmts)
 110 {
 111         struct grub2_statement *stmt;
 112         int rc = 0;
 113
 114         list_for_each_entry(&stmts->list, stmt, list) {
 115                 if (stmt->exec)
 116                         rc = stmt->exec(script, stmt);
 117         }
 118         return rc;
 119 }
 120
 121 int statement_simple_execute(struct grub2_script *script,
 122                 struct grub2_statement *statement)
 123 {
 124         struct grub2_statement_simple *st = to_stmt_simple(statement);
 125         struct grub2_command *cmd;
 126         int rc;
 127
 128         if (!st->argv)
 129                 return 0;
 130
 131         process_expansions(script, st->argv);
 132
 133         if (!st->argv->argc)
 134                 return 0;
 135
 136         cmd = script_lookup_command(script, st->argv->argv[0]);
 137         if (!cmd) {
 138                 fprintf(stderr, "undefined command '%s'\n", st->argv->argv[0]);
 139                 return 0;
 140         }
 141
 142         rc = cmd->exec(script, st->argv->argc, st->argv->argv);
 143
 144         return rc;
 145 }
 146
 147 int statement_if_execute(struct grub2_script *script,
 148                 struct grub2_statement *statement)
 149 {
 150         struct grub2_statement_if *st = to_stmt_if(statement);
 151         struct grub2_statements *case_stmts;
 152         int rc;
 153
 154         rc = st->condition->exec(script, st->condition);
 155
 156         if (rc == 0)
 157                 case_stmts = st->true_case;
 158         else
 159                 case_stmts = st->false_case;
 160
 161         if (case_stmts)
 162                 statements_execute(script, case_stmts);
 163         else
 164                 rc = 0;
 165
 166         return rc;
 167 }
 168
 169 int statement_menuentry_execute(struct grub2_script *script,
 170                 struct grub2_statement *statement)
 171 {
 172         struct grub2_statement_menuentry *st = to_stmt_menuentry(statement);
 173
 174         process_expansions(script, st->argv);
 175         statements_execute(script, st->statements);
 176
 177         return 0;
 178 }
 179
 180 static void init_env(struct grub2_script *script)
 181 {
 182         struct env_entry *env;
 183
 184         list_init(&script->environment);
 185
 186         env = talloc(script, struct env_entry);
 187         env->name = talloc_strdup(env, "prefix");
 188         env->value = talloc_strdup(env, "/");
 189
 190         list_add(&script->environment, &env->list);
 191 }
 192
 193 struct grub2_command *script_lookup_command(struct grub2_script *script,
 194                 const char *name)
 195 {
 196         struct grub2_command *command;
 197
 198         list_for_each_entry(&script->commands, command, list) {
 199                 if (!strcmp(command->name, name))
 200                         return command;
 201         }
 202
 203         return NULL;
 204 }
 205
 206 void script_register_command(struct grub2_script *script,
 207                 struct grub2_command *command)
 208 {
 209         list_add(&script->commands, &command->list);
 210 }
 211
 212
 213 void script_execute(struct grub2_script *script)
 214 {
 215         statements_execute(script, script->statements);
 216 }
 217
 218 struct grub2_script *create_script(void *ctx)
 219 {
 220         struct grub2_script *script;
 221
 222         script = talloc(ctx, struct grub2_script);
 223
 224         init_env(script);
 225         list_init(&script->commands);
 226         register_builtins(script);
 227
 228         return script;
 229 }
 230