1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
|
#include <sys/types.h>
#include <regex.h>
#include <string.h>
#include <talloc/talloc.h>
#include "grub2.h"
#define to_stmt_simple(stmt) \
container_of(stmt, struct grub2_statement_simple, st)
#define to_stmt_if(stmt) \
container_of(stmt, struct grub2_statement_if, st)
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;
list_for_each_entry(&script->environment, entry, list)
if (!strncmp(entry->name, name, name_len)
&& entry->name[name_len] == '\0')
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, i;
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));
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);
}
}
int statements_execute(struct grub2_script *script,
struct grub2_statements *stmts)
{
struct grub2_statement *stmt;
int rc = 0;
list_for_each_entry(&stmts->list, stmt, list) {
if (stmt->exec)
rc = stmt->exec(script, stmt);
}
return rc;
}
int statement_simple_execute(struct grub2_script *script,
struct grub2_statement *statement)
{
struct grub2_statement_simple *st = to_stmt_simple(statement);
if (!st->argv)
return 0;
process_expansions(script, st->argv);
return 0;
}
int statement_if_execute(struct grub2_script *script,
struct grub2_statement *statement)
{
struct grub2_statement_if *st = to_stmt_if(statement);
struct grub2_statements *case_stmts;
int rc;
rc = st->condition->exec(script, st->condition);
if (rc == 0)
case_stmts = st->true_case;
else
case_stmts = st->false_case;
if (case_stmts)
statements_execute(script, case_stmts);
else
rc = 0;
return rc;
}
static void init_env(struct grub2_script *script)
{
struct env_entry *env;
list_init(&script->environment);
env = talloc(script, struct env_entry);
env->name = talloc_strdup(env, "prefix");
env->value = talloc_strdup(env, "/");
list_add(&script->environment, &env->list);
}
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;
}
|
