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
  14 struct env_entry {
  15         const char              *name;
  16         const char              *value;
  17         struct list_item        list;
  18 };
  19
  20 static const char *env_lookup(struct grub2_script *script,
  21                 const char *name)
  22 {
  23         struct env_entry *entry;
  24
  25         list_for_each_entry(&script->environment, entry, list)
  26                 if (!strcmp(entry->name, name))
  27                         return entry->value;
  28
  29         return NULL;
  30 }
  31
  32 static bool expand_var(struct grub2_script *script, struct grub2_word *word)
  33 {
  34         const char *val;
  35
  36         val = env_lookup(script, word->var.name);
  37         if (!val)
  38                 val = "";
  39
  40         word->type = GRUB2_WORD_TEXT;
  41         word->text = talloc_strdup(script, val);
  42
  43         return true;
  44 }
  45
  46 /* iterate through the words in an argv, looking for GRUB2_WORD_VAR expansions.
  47  *
  48  * Once that's done, we may (if split == true) have to split the word to create
  49  * new argv items
  50  */
  51 static void process_expansions(struct grub2_script *script,
  52                 struct grub2_argv *argv)
  53 {
  54         struct grub2_word *top_word, *word;
  55
  56         list_for_each_entry(&argv->words, top_word, argv_list) {
  57                 /* expand vars and squash the list of words into the top struct.
  58                  * todo: splitting
  59                  */
  60                 for (word = top_word; word; word = word->next) {
  61                         if (word->type == GRUB2_WORD_VAR)
  62                                 expand_var(script, word);
  63
  64                         if (word == top_word)
  65                                 continue;
  66
  67                         top_word->text = talloc_asprintf_append(top_word->text,
  68                                         "%s", word->text);
  69                 }
  70                 top_word->next = NULL;
  71         }
  72 }
  73
  74 int statements_execute(struct grub2_script *script,
  75                 struct grub2_statements *stmts)
  76 {
  77         struct grub2_statement *stmt;
  78         int rc = 0;
  79
  80         list_for_each_entry(&stmts->list, stmt, list) {
  81                 if (stmt->exec)
  82                         rc = stmt->exec(script, stmt);
  83         }
  84         return rc;
  85 }
  86
  87 int statement_simple_execute(struct grub2_script *script,
  88                 struct grub2_statement *statement)
  89 {
  90         struct grub2_statement_simple *st = to_stmt_simple(statement);
  91
  92         if (!st->argv)
  93                 return 0;
  94
  95         process_expansions(script, st->argv);
  96
  97         return 0;
  98 }
  99
 100 int statement_if_execute(struct grub2_script *script,
 101                 struct grub2_statement *statement)
 102 {
 103         struct grub2_statement_if *st = to_stmt_if(statement);
 104         struct grub2_statements *case_stmts;
 105         int rc;
 106
 107         rc = st->condition->exec(script, st->condition);
 108
 109         if (rc == 0)
 110                 case_stmts = st->true_case;
 111         else
 112                 case_stmts = st->false_case;
 113
 114         if (case_stmts)
 115                 statements_execute(script, case_stmts);
 116         else
 117                 rc = 0;
 118
 119         return rc;
 120 }
 121
 122 static void init_env(struct grub2_script *script)
 123 {
 124         struct env_entry *env;
 125
 126         list_init(&script->environment);
 127
 128         env = talloc(script, struct env_entry);
 129         env->name = talloc_strdup(env, "prefix");
 130         env->value = talloc_strdup(env, "/");
 131
 132         list_add(&script->environment, &env->list);
 133 }
 134
 135
 136 void script_execute(struct grub2_script *script)
 137 {
 138         statements_execute(script, script->statements);
 139 }
 140
 141 struct grub2_script *create_script(void *ctx)
 142 {
 143         struct grub2_script *script;
 144
 145         script = talloc(ctx, struct grub2_script);
 146
 147         init_env(script);
 148
 149         return script;
 150 }
 151