discover/grub2: Add var expansion code

Still todo: splitting.

Signed-off-by: Jeremy Kerr <jk@ozlabs.org>

diff --git a/discover/grub2/grub2.h b/discover/grub2/grub2.h
index f3ad2e5b48491e30eb5d15c025d8c617e3b13284..33180d49125438519c51b5a905081abe1089ddf7 100644 (file)
--- a/discover/grub2/grub2.h
+++ b/discover/grub2/grub2.h
@@ -1,6 +1,7 @@
 #ifndef GRUB2_H
 #define GRUB2_H
 
+#include <regex.h>
 #include <stdbool.h>
 #include <list/list.h>
 
@@ -57,6 +58,8 @@ struct grub2_statement_block {
 
 struct grub2_script {
        struct grub2_statements *statements;
+       struct list             environment;
+       regex_t                 var_re;
 };
 
 struct grub2_parser {

diff --git a/discover/grub2/script.c b/discover/grub2/script.c
index 71d6cba81a77cfabf37d2fc6bacfcf0d42092973..067b0c9440857f48b0ce4c0ad84c3e3e559484ac 100644 (file)
--- a/discover/grub2/script.c
+++ b/discover/grub2/script.c
@@ -1,12 +1,108 @@
 
+#include <sys/types.h>
+#include <regex.h>
+#include <string.h>
+
 #include <talloc/talloc.h>
 
 #include "grub2.h"
 
+struct env_entry {
+       const char              *name;
+       const char              *value;
+       struct list_item        list;
+};
+
+static const char *env_lookup(struct grub2_script *script,
+               const char *name, int name_len)
+{
+       struct env_entry *entry;
+       const char *str;
+
+       str = talloc_strndup(script, name, name_len);
+       printf("%s: %s\n", __func__, str);
+
+       list_for_each_entry(&script->environment, entry, list)
+               if (!strncmp(entry->name, name, name_len))
+                       return entry->value;
+
+       return NULL;
+}
+
+static bool expand_word(struct grub2_script *script, struct grub2_word *word)
+{
+       const char *val, *src;
+       char *dest = NULL;
+       regmatch_t match;
+       int n;
+
+       src = word->text;
+
+       n = regexec(&script->var_re, src, 1, &match, 0);
+       if (n == 0)
+               return false;
+
+       val = env_lookup(script, src + match.rm_so,
+                                match.rm_eo - match.rm_so);
+       if (val)
+               val = "";
+
+       dest = talloc_strndup(script, src, match.rm_so);
+       dest = talloc_asprintf_append(dest, "%s%s", val, src + match.rm_eo);
+
+       word->text = dest;
+       return true;
+}
+
+/* iterate through the words in an argv, looking for expansions. If a
+ * word is marked with expand == true, then we process any variable
+ * substitutions.
+ *
+ * Once that's done, we may (if split == true) have to split the word to create
+ * new argv items
+ */
+static void process_expansions(struct grub2_script *script,
+               struct grub2_argv *argv)
+{
+       struct grub2_word *word;
+
+       list_for_each_entry(&argv->words, word, argv_list) {
+               if (!word->expand)
+                       continue;
+
+               expand_word(script, word);
+       }
+}
+
+static int script_destroy(void *p)
+{
+       struct grub2_script *script = p;
+       regfree(&script->var_re);
+       return 0;
+}
+
 struct grub2_script *create_script(void *ctx)
 {
        struct grub2_script *script;
+       int rc;
+
        script = talloc(ctx, struct grub2_script);
+
+       rc = regcomp(&script->var_re,
+               "\\$\\{?([[:alpha:]][_[:alnum:]]*|[0-9]|[\\?@\\*#])\\}?",
+                       REG_EXTENDED);
+       if (rc) {
+               char err[200];
+               regerror(rc, &script->var_re, err, sizeof(err));
+               fprintf(stderr, "RE error %d: %s\n", rc, err);
+               talloc_free(script);
+               return NULL;
+
+       }
+       talloc_set_destructor(script, script_destroy);
+
+       list_init(&script->environment);
+
        return script;
 }