discover/grub2: Handle var tokens in lexer

Rather than post-processing to expand variables, use the lexer to
identify variable tokens as a type of grub2_word.

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

diff --git a/discover/grub2/grub2.h b/discover/grub2/grub2.h
index 07a1e6c7fe3517deb46e4786472cab0312a82f64..cbd69dc70188b27cd5ae8c77fc4ce404b3c0de3d 100644 (file)
--- a/discover/grub2/grub2.h
+++ b/discover/grub2/grub2.h
@@ -1,16 +1,23 @@
 #ifndef GRUB2_H
 #define GRUB2_H
 
-#include <regex.h>
 #include <stdbool.h>
 #include <list/list.h>
 
 struct grub2_script;
 
 struct grub2_word {
-       const char              *text;
-       bool                    expand;
-       bool                    split;
+       enum {
+               GRUB2_WORD_TEXT,
+               GRUB2_WORD_VAR,
+       } type;
+       union {
+               char    *text;
+               struct {
+                       const char      *name;
+                       bool            split;
+               } var;
+       };
        struct grub2_word       *next;
        struct list_item        argv_list;
 };
@@ -61,7 +68,6 @@ struct grub2_statement_block {
 struct grub2_script {
        struct grub2_statements *statements;
        struct list             environment;
-       regex_t                 var_re;
 };
 
 struct grub2_parser {
@@ -85,8 +91,11 @@ struct grub2_statement *create_statement_if(struct grub2_parser *parser,
 struct grub2_statement *create_statement_block(struct grub2_parser *parser,
                struct grub2_statements *stmts);
 
-struct grub2_word *create_word(struct grub2_parser *parser, const char *text,
-               bool expand, bool split);
+struct grub2_word *create_word_text(struct grub2_parser *parser,
+               const char *text);
+
+struct grub2_word *create_word_var(struct grub2_parser *parser,
+               const char *name, bool split);
 
 struct grub2_argv *create_argv(struct grub2_parser *parser);
 

diff --git a/discover/grub2/lexer.l b/discover/grub2/lexer.l
index 64eee279a3d0f3311c5c3cfe9770dfb5bd69797d..ab26f4be2e1b465e5522d02299b3703ef3465e5e 100644 (file)
--- a/discover/grub2/lexer.l
+++ b/discover/grub2/lexer.l
@@ -51,15 +51,19 @@ VARNAME ([[:alpha:]][_[:alnum:]]*|[0-9]|[\?@\*#])
 
  /* anything that's not a metachar: return as a plain word */
 {WORD} {
-               yylval->word = create_word(yyget_extra(yyscanner), yytext,
-                                               false, false);
+               yylval->word = create_word_text(yyget_extra(yyscanner), yytext);
                return TOKEN_WORD;
        }
 
 \${VARNAME} |
 \$\{{VARNAME}\} {
-               yylval->word = create_word(yyget_extra(yyscanner), yytext,
-                                               true, true);
+               if (yytext[1] == '{') {
+                       yytext[yyleng-1] = '\0';
+                       yytext++;
+               }
+               yytext++;
+               yylval->word = create_word_var(yyget_extra(yyscanner), yytext,
+                                               true);
                return TOKEN_WORD;
        }
 
@@ -71,8 +75,7 @@ VARNAME ([[:alpha:]][_[:alnum:]]*|[0-9]|[\?@\*#])
                yy_pop_state(yyscanner);
        }
 <sqstring>[^']+ {
-               yylval->word = create_word(yyget_extra(yyscanner), yytext,
-                                               false, false);
+               yylval->word = create_word_text(yyget_extra(yyscanner), yytext);
                return TOKEN_WORD;
        }
 
@@ -83,11 +86,22 @@ VARNAME ([[:alpha:]][_[:alnum:]]*|[0-9]|[\?@\*#])
 <dqstring>\" {
                yy_pop_state(yyscanner);
        }
-<dqstring>([^"]|\\\")+ {
-               yylval->word = create_word(yyget_extra(yyscanner), yytext,
-                                               true, false);
+<dqstring>([^"\$]|\\\")+ {
+               yylval->word = create_word_text(yyget_extra(yyscanner), yytext);
                return TOKEN_WORD;
        }
+<dqstring>\${VARNAME} |
+<dqstring>\$\{{VARNAME}\} {
+               if (yytext[1] == '{') {
+                       yytext[yyleng-1] = '\0';
+                       yytext++;
+               }
+               yytext++;
+               yylval->word = create_word_var(yyget_extra(yyscanner), yytext,
+                                               false);
+               return TOKEN_WORD;
+       }
+
 
 
  /* blocks */

diff --git a/discover/grub2/parser-api.c b/discover/grub2/parser-api.c
index 9ccf15eb94ffefdf7fe53ae96f3def672edaab2d..765bd873e2fa4d333062fb5ce9484647593c2db2 100644 (file)
--- a/discover/grub2/parser-api.c
+++ b/discover/grub2/parser-api.c
@@ -68,13 +68,23 @@ void statement_append(struct grub2_statements *stmts,
        list_add_tail(&stmts->list, &stmt->list);
 }
 
-struct grub2_word *create_word(struct grub2_parser *parser, const char *text,
-               bool expand, bool split)
+struct grub2_word *create_word_text(struct grub2_parser *parser,
+               const char *text)
 {
        struct grub2_word *word = talloc(parser, struct grub2_word);
+       word->type = GRUB2_WORD_TEXT;
        word->text = talloc_strdup(word, text);
-       word->expand = expand;
-       word->split = split;
+       word->next = NULL;
+       return word;
+}
+
+struct grub2_word *create_word_var(struct grub2_parser *parser,
+               const char *name, bool split)
+{
+       struct grub2_word *word = talloc(parser, struct grub2_word);
+       word->type = GRUB2_WORD_VAR;
+       word->var.name = talloc_strdup(word, name);
+       word->var.split = split;
        word->next = NULL;
        return word;
 }

diff --git a/discover/grub2/script.c b/discover/grub2/script.c
index 3fee4705622524f34d0139f1861e2cc07b789932..536139418d93b89457743bc35688bb03103e0fb6 100644 (file)
--- a/discover/grub2/script.c
+++ b/discover/grub2/script.c
@@ -1,6 +1,5 @@
 
 #include <sys/types.h>
-#include <regex.h>
 #include <string.h>
 
 #include <talloc/talloc.h>
@@ -19,50 +18,32 @@ struct env_entry {
 };
 
 static const char *env_lookup(struct grub2_script *script,
-               const char *name, int name_len)
+               const char *name)
 {
        struct env_entry *entry;
 
        list_for_each_entry(&script->environment, entry, list)
-               if (!strncmp(entry->name, name, name_len)
-                               && entry->name[name_len] == '\0')
+               if (!strcmp(entry->name, name))
                        return entry->value;
 
        return NULL;
 }
 
-static bool expand_word(struct grub2_script *script, struct grub2_word *word)
+static bool expand_var(struct grub2_script *script, struct grub2_word *word)
 {
-       const char *val, *src;
-       char *dest = NULL;
-       regmatch_t match;
-       int n, i;
+       const char *val;
 
-       src = word->text;
-
-       n = regexec(&script->var_re, src, 1, &match, 0);
-       if (n != 0)
-               return false;
-
-       i = 0;
-       if (src[match.rm_so + 1] == '{')
-               i++;
-
-       val = env_lookup(script, src + match.rm_so + 1 + i,
-                                match.rm_eo - match.rm_so - 1 - (i * 2));
+       val = env_lookup(script, word->var.name);
        if (!val)
                val = "";
 
-       dest = talloc_strndup(script, src, match.rm_so);
-       dest = talloc_asprintf_append(dest, "%s%s", val, src + match.rm_eo);
+       word->type = GRUB2_WORD_TEXT;
+       word->text = talloc_strdup(script, val);
 
-       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.
+/* iterate through the words in an argv, looking for GRUB2_WORD_VAR expansions.
  *
  * Once that's done, we may (if split == true) have to split the word to create
  * new argv items
@@ -70,13 +51,23 @@ static bool expand_word(struct grub2_script *script, struct grub2_word *word)
 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);
+       struct grub2_word *top_word, *word;
+
+       list_for_each_entry(&argv->words, top_word, argv_list) {
+               /* expand vars and squash the list of words into the top struct.
+                * todo: splitting
+                */
+               for (word = top_word; word; word = word->next) {
+                       if (word->type == GRUB2_WORD_VAR)
+                               expand_var(script, word);
+
+                       if (word == top_word)
+                               continue;
+
+                       top_word->text = talloc_asprintf_append(top_word->text,
+                                       "%s", word->text);
+               }
+               top_word->next = NULL;
        }
 }
 
@@ -147,33 +138,12 @@ void script_execute(struct grub2_script *script)
        statements_execute(script, script->statements);
 }
 
-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);
-
        init_env(script);
 
        return script;