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authorDenys Vlasenko <vda.linux@googlemail.com>2009-11-17 02:35:31 (GMT)
committer Denys Vlasenko <vda.linux@googlemail.com>2009-11-17 02:35:31 (GMT)
commitf3e2818895a6f570a365001f625946a1b75c085a (patch)
tree8bd5ba3dad83b32439be4f7e166aa0eb6ab6384e
parent160746b60398a8a018e1791e259504f9d97a1b33 (diff)
downloadbusybox-f3e2818895a6f570a365001f625946a1b75c085a.tar.gz
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hush: improve HUSH_BRACE_EXP code (still disabled). ~0 bytes
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
-rw-r--r--shell/hush.c225
-rw-r--r--shell/hush_test/hush-parsing/brace2.right3
-rwxr-xr-xshell/hush_test/hush-parsing/brace2.tests5
3 files changed, 171 insertions, 62 deletions
diff --git a/shell/hush.c b/shell/hush.c
index 24134fd..2d6f55b 100644
--- a/shell/hush.c
+++ b/shell/hush.c
@@ -889,18 +889,6 @@ static void cmdedit_update_prompt(void);
/* Utility functions
*/
-static int glob_needed(const char *s)
-{
- while (*s) {
- if (*s == '\\')
- s++;
- if (*s == '*' || *s == '[' || *s == '?')
- return 1;
- s++;
- }
- return 0;
-}
-
static int is_well_formed_var_name(const char *s, char terminator)
{
if (!s || !(isalpha(*s) || *s == '_'))
@@ -1856,13 +1844,31 @@ static void o_addblock_duplicate_backslash(o_string *o, const char *str, int len
}
}
+#undef HUSH_BRACE_EXP
+/*
+ * HUSH_BRACE_EXP code needs corresponding quoting on variable expansion side.
+ * Currently, "v='{q,w}'; echo $v" erroneously expands braces in $v.
+ * Apparently, on unquoted $v bash still does globbing
+ * ("v='*.txt'; echo $v" prints all .txt files),
+ * but NOT brace expansion! Thus, there should be TWO independent
+ * quoting mechanisms on $v expansion side: one protects
+ * $v from brace expansion, and other additionally protects "$v" against globbing.
+ * We have only second one.
+ */
+
+#ifdef HUSH_BRACE_EXP
+# define MAYBE_BRACES "{}"
+#else
+# define MAYBE_BRACES ""
+#endif
+
/* My analysis of quoting semantics tells me that state information
* is associated with a destination, not a source.
*/
static void o_addqchr(o_string *o, int ch)
{
int sz = 1;
- char *found = strchr("*?[\\", ch);
+ char *found = strchr("*?[\\" MAYBE_BRACES, ch);
if (found)
sz++;
o_grow_by(o, sz);
@@ -1878,7 +1884,7 @@ static void o_addqchr(o_string *o, int ch)
static void o_addQchr(o_string *o, int ch)
{
int sz = 1;
- if (o->o_escape && strchr("*?[\\", ch)) {
+ if (o->o_escape && strchr("*?[\\" MAYBE_BRACES, ch)) {
sz++;
o->data[o->length] = '\\';
o->length++;
@@ -1898,7 +1904,7 @@ static void o_addQstr(o_string *o, const char *str, int len)
while (len) {
char ch;
int sz;
- int ordinary_cnt = strcspn(str, "*?[\\");
+ int ordinary_cnt = strcspn(str, "*?[\\" MAYBE_BRACES);
if (ordinary_cnt > len) /* paranoia */
ordinary_cnt = len;
o_addblock(o, str, ordinary_cnt);
@@ -1909,7 +1915,7 @@ static void o_addQstr(o_string *o, const char *str, int len)
ch = *str++;
sz = 1;
- if (ch) { /* it is necessarily one of "*?[\\" */
+ if (ch) { /* it is necessarily one of "*?[\\" MAYBE_BRACES */
sz++;
o->data[o->length] = '\\';
o->length++;
@@ -2003,16 +2009,29 @@ static int o_get_last_ptr(o_string *o, int n)
return ((int)(ptrdiff_t)list[n-1]) + string_start;
}
-#undef HUSH_BRACE_EXP
+#ifdef HUSH_BRACE_EXP
/* There in a GNU extension, GLOB_BRACE, but it is not usable:
* first, it processes even {a} (no commas), second,
* I didn't manage to make it return strings when they don't match
* existing files. Need to re-implement it.
- *
- * This code needs corresponding quoting on variable expansion side.
- * Currently, "a='{q,w}'; echo $a" erroneously expands braces in $a
*/
-#ifdef HUSH_BRACE_EXP
+
+/* Helper */
+static int glob_needed(const char *s)
+{
+ while (*s) {
+ if (*s == '\\') {
+ if (!s[1])
+ return 0;
+ s += 2;
+ continue;
+ }
+ if (*s == '*' || *s == '[' || *s == '?' || *s == '{')
+ return 1;
+ s++;
+ }
+ return 0;
+}
/* Return pointer to next closing brace or to comma */
static const char *next_brace_sub(const char *cp)
{
@@ -2033,29 +2052,29 @@ static const char *next_brace_sub(const char *cp)
return *cp != '\0' ? cp : NULL;
}
-static int glob_brace(const char *pattern, int flags, glob_t *pglob)
+/* Recursive brace globber. Note: may garble pattern[]. */
+static int glob_brace(char *pattern, o_string *o, int n)
{
+ char *new_pattern_buf;
const char *begin;
- char *alt_start;
- const char *p;
const char *next;
const char *rest;
+ const char *p;
size_t rest_len;
- char *onealt;
debug_printf_glob("glob_brace('%s')\n", pattern);
begin = pattern;
while (1) {
if (*begin == '\0')
- goto do_glob;
+ goto simple_glob;
if (*begin == '{') /*}*/ {
/* Find the first sub-pattern and at the same time
* find the rest after the closing brace */
next = next_brace_sub(begin);
if (next == NULL) {
/* An illegal expression */
- goto do_glob;
+ goto simple_glob;
}
/*{*/ if (*next == '}') {
/* "{abc}" with no commas - illegal
@@ -2078,7 +2097,7 @@ static int glob_brace(const char *pattern, int flags, glob_t *pglob)
rest = next_brace_sub(rest);
if (rest == NULL) {
/* An illegal expression */
- goto do_glob;
+ goto simple_glob;
}
debug_printf_glob("rest:%s\n", rest);
}
@@ -2087,9 +2106,7 @@ static int glob_brace(const char *pattern, int flags, glob_t *pglob)
/* We are sure the brace expression is well-formed */
/* Allocate working buffer large enough for our work */
- onealt = alloca(strlen(pattern));
- /* We know the prefix for all sub-patterns */
- alt_start = mempcpy(onealt, pattern, begin - pattern);
+ new_pattern_buf = xmalloc(strlen(pattern));
/* We have a brace expression. BEGIN points to the opening {,
* NEXT points past the terminator of the first element, and REST
@@ -2099,18 +2116,19 @@ static int glob_brace(const char *pattern, int flags, glob_t *pglob)
p = begin + 1;
while (1) {
- int result;
-
/* Construct the new glob expression */
- memcpy(mempcpy(alt_start, p, next - p), rest, rest_len);
-
- result = glob_brace(onealt, flags, pglob);
- /* If we got an error, return it */
- if (result && result != GLOB_NOMATCH)
- return result;
-
- flags |= GLOB_APPEND;
-
+ memcpy(
+ mempcpy(
+ mempcpy(new_pattern_buf,
+ /* We know the prefix for all sub-patterns */
+ pattern, begin - pattern),
+ p, next - p),
+ rest, rest_len);
+
+ /* Note: glob_brace() may garble new_pattern_buf[].
+ * That's why we re-copy prefix every time (1st memcpy above).
+ */
+ n = glob_brace(new_pattern_buf, o, n);
/*{*/ if (*next == '}') {
/* We saw the last entry */
break;
@@ -2118,17 +2136,96 @@ static int glob_brace(const char *pattern, int flags, glob_t *pglob)
p = next + 1;
next = next_brace_sub(next);
}
+ free(new_pattern_buf);
+ return n;
- /* We found some entries */
- return 0;
+ simple_glob:
+ {
+ int gr;
+ glob_t globdata;
+
+ memset(&globdata, 0, sizeof(globdata));
+ gr = glob(pattern, 0, NULL, &globdata);
+ debug_printf_glob("glob('%s'):%d\n", pattern, gr);
+ if (gr != 0) {
+ if (gr == GLOB_NOMATCH) {
+ globfree(&globdata);
+ /* NB: garbles parameter */
+ unbackslash(pattern);
+ o_addstr_with_NUL(o, pattern);
+ debug_printf_glob("glob pattern '%s' is literal\n", pattern);
+ return o_save_ptr_helper(o, n);
+ }
+ if (gr == GLOB_NOSPACE)
+ bb_error_msg_and_die(bb_msg_memory_exhausted);
+ /* GLOB_ABORTED? Only happens with GLOB_ERR flag,
+ * but we didn't specify it. Paranoia again. */
+ bb_error_msg_and_die("glob error %d on '%s'", gr, pattern);
+ }
+ if (globdata.gl_pathv && globdata.gl_pathv[0]) {
+ char **argv = globdata.gl_pathv;
+ while (1) {
+ o_addstr_with_NUL(o, *argv);
+ n = o_save_ptr_helper(o, n);
+ argv++;
+ if (!*argv)
+ break;
+ }
+ }
+ globfree(&globdata);
+ }
+ return n;
+}
+/* Performs globbing on last list[],
+ * saving each result as a new list[].
+ */
+static int o_glob(o_string *o, int n)
+{
+ char *pattern, *copy;
+
+ debug_printf_glob("start o_glob: n:%d o->data:%p\n", n, o->data);
+ if (!o->data)
+ return o_save_ptr_helper(o, n);
+ pattern = o->data + o_get_last_ptr(o, n);
+ debug_printf_glob("glob pattern '%s'\n", pattern);
+ if (!glob_needed(pattern)) {
+ /* unbackslash last string in o in place, fix length */
+ o->length = unbackslash(pattern) - o->data;
+ debug_printf_glob("glob pattern '%s' is literal\n", pattern);
+ return o_save_ptr_helper(o, n);
+ }
- do_glob:
- return glob(pattern, flags, NULL, pglob);
+ copy = xstrdup(pattern);
+ /* "forget" pattern in o */
+ o->length = pattern - o->data;
+ n = glob_brace(copy, o, n);
+ free(copy);
+ if (DEBUG_GLOB)
+ debug_print_list("o_glob returning", o, n);
+ return n;
}
-#endif
-/* o_glob performs globbing on last list[], saving each result
- * as a new list[]. */
+#else
+
+/* Helper */
+static int glob_needed(const char *s)
+{
+ while (*s) {
+ if (*s == '\\') {
+ if (!s[1])
+ return 0;
+ s += 2;
+ continue;
+ }
+ if (*s == '*' || *s == '[' || *s == '?')
+ return 1;
+ s++;
+ }
+ return 0;
+}
+/* Performs globbing on last list[],
+ * saving each result as a new list[].
+ */
static int o_glob(o_string *o, int n)
{
glob_t globdata;
@@ -2142,33 +2239,35 @@ static int o_glob(o_string *o, int n)
debug_printf_glob("glob pattern '%s'\n", pattern);
if (!glob_needed(pattern)) {
literal:
+ /* unbackslash last string in o in place, fix length */
o->length = unbackslash(pattern) - o->data;
debug_printf_glob("glob pattern '%s' is literal\n", pattern);
return o_save_ptr_helper(o, n);
}
memset(&globdata, 0, sizeof(globdata));
-#ifdef HUSH_BRACE_EXP
- gr = glob_brace(pattern, GLOB_NOCHECK, &globdata);
- debug_printf_glob("glob_brace('%s'):%d\n", pattern, gr);
-#else
+ /* Can't use GLOB_NOCHECK: it does not unescape the string.
+ * If we glob "*.\*" and don't find anything, we need
+ * to fall back to using literal "*.*", but GLOB_NOCHECK
+ * will return "*.\*"!
+ */
gr = glob(pattern, 0, NULL, &globdata);
debug_printf_glob("glob('%s'):%d\n", pattern, gr);
-#endif
- if (gr == GLOB_NOSPACE)
- bb_error_msg_and_die(bb_msg_memory_exhausted);
- if (gr == GLOB_NOMATCH) {
- globfree(&globdata);
- goto literal;
- }
if (gr != 0) {
+ if (gr == GLOB_NOMATCH) {
+ globfree(&globdata);
+ goto literal;
+ }
+ if (gr == GLOB_NOSPACE)
+ bb_error_msg_and_die(bb_msg_memory_exhausted);
/* GLOB_ABORTED? Only happens with GLOB_ERR flag,
* but we didn't specify it. Paranoia again. */
- bb_error_msg("glob(3) error %d on '%s'", gr, pattern);
+ bb_error_msg_and_die("glob error %d on '%s'", gr, pattern);
}
if (globdata.gl_pathv && globdata.gl_pathv[0]) {
char **argv = globdata.gl_pathv;
- o->length = pattern - o->data; /* "forget" pattern */
+ /* "forget" pattern in o */
+ o->length = pattern - o->data;
while (1) {
o_addstr_with_NUL(o, *argv);
n = o_save_ptr_helper(o, n);
@@ -2183,6 +2282,8 @@ static int o_glob(o_string *o, int n)
return n;
}
+#endif
+
/* If o->o_glob == 1, glob the string so far remembered.
* Otherwise, just finish current list[] and start new */
static int o_save_ptr(o_string *o, int n)
diff --git a/shell/hush_test/hush-parsing/brace2.right b/shell/hush_test/hush-parsing/brace2.right
new file mode 100644
index 0000000..37a9666
--- /dev/null
+++ b/shell/hush_test/hush-parsing/brace2.right
@@ -0,0 +1,3 @@
+{q,w}
+{q,w}
+Done
diff --git a/shell/hush_test/hush-parsing/brace2.tests b/shell/hush_test/hush-parsing/brace2.tests
new file mode 100755
index 0000000..ef75f0b
--- /dev/null
+++ b/shell/hush_test/hush-parsing/brace2.tests
@@ -0,0 +1,5 @@
+v='{q,w}'
+# Should not brace-expand v value
+echo $v
+echo "$v"
+echo Done