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 static const char *env_lookup(struct grub2_script *script,
  23                 const char *name)
  24 {
  25         struct env_entry *entry;
  26
  27         list_for_each_entry(&script->environment, entry, list)
  28                 if (!strcmp(entry->name, name))
  29                         return entry->value;
  30
  31         return NULL;
  32 }
  33
  34 static bool expand_var(struct grub2_script *script, struct grub2_word *word)
  35 {
  36         const char *val;
  37
  38         val = env_lookup(script, word->var.name);
  39         if (!val)
  40                 val = "";
  41
  42         word->type = GRUB2_WORD_TEXT;
  43         word->text = talloc_strdup(script, val);
  44
  45         return true;
  46 }
  47
  48 /* iterate through the words in an argv, looking for GRUB2_WORD_VAR expansions.
  49  *
  50  * Once that's done, we may (if split == true) have to split the word to create
  51  * new argv items
  52  */
  53 static void process_expansions(struct grub2_script *script,
  54                 struct grub2_argv *argv)
  55 {
  56         struct grub2_word *top_word, *word;
  57
  58         list_for_each_entry(&argv->words, top_word, argv_list) {
  59                 /* expand vars and squash the list of words into the top struct.
  60                  * todo: splitting
  61                  */
  62                 for (word = top_word; word; word = word->next) {
  63                         if (word->type == GRUB2_WORD_VAR)
  64                                 expand_var(script, word);
  65
  66                         if (word == top_word)
  67                                 continue;
  68
  69                         top_word->text = talloc_asprintf_append(top_word->text,
  70                                         "%s", word->text);
  71                 }
  72                 top_word->next = NULL;
  73         }
  74 }
  75
  76 int statements_execute(struct grub2_script *script,
  77                 struct grub2_statements *stmts)
  78 {
  79         struct grub2_statement *stmt;
  80         int rc = 0;
  81
  82         list_for_each_entry(&stmts->list, stmt, list) {
  83                 if (stmt->exec)
  84                         rc = stmt->exec(script, stmt);
  85         }
  86         return rc;
  87 }
  88
  89 int statement_simple_execute(struct grub2_script *script,
  90                 struct grub2_statement *statement)
  91 {
  92         struct grub2_statement_simple *st = to_stmt_simple(statement);
  93
  94         if (!st->argv)
  95                 return 0;
  96
  97         process_expansions(script, st->argv);
  98
  99         return 0;
 100 }
 101
 102 int statement_if_execute(struct grub2_script *script,
 103                 struct grub2_statement *statement)
 104 {
 105         struct grub2_statement_if *st = to_stmt_if(statement);
 106         struct grub2_statements *case_stmts;
 107         int rc;
 108
 109         rc = st->condition->exec(script, st->condition);
 110
 111         if (rc == 0)
 112                 case_stmts = st->true_case;
 113         else
 114                 case_stmts = st->false_case;
 115
 116         if (case_stmts)
 117                 statements_execute(script, case_stmts);
 118         else
 119                 rc = 0;
 120
 121         return rc;
 122 }
 123
 124 int statement_menuentry_execute(struct grub2_script *script,
 125                 struct grub2_statement *statement)
 126 {
 127         struct grub2_statement_menuentry *st = to_stmt_menuentry(statement);
 128
 129         process_expansions(script, st->argv);
 130         statements_execute(script, st->statements);
 131
 132         return 0;
 133 }
 134
 135 static void init_env(struct grub2_script *script)
 136 {
 137         struct env_entry *env;
 138
 139         list_init(&script->environment);
 140
 141         env = talloc(script, struct env_entry);
 142         env->name = talloc_strdup(env, "prefix");
 143         env->value = talloc_strdup(env, "/");
 144
 145         list_add(&script->environment, &env->list);
 146 }
 147
 148
 149 void script_execute(struct grub2_script *script)
 150 {
 151         statements_execute(script, script->statements);
 152 }
 153
 154 struct grub2_script *create_script(void *ctx)
 155 {
 156         struct grub2_script *script;
 157
 158         script = talloc(ctx, struct grub2_script);
 159
 160         init_env(script);
 161
 162         return script;
 163 }
 164