hush: initial stab at brace expansion support

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
This commit is contained in:
Denys Vlasenko 2009-11-16 05:49:36 +01:00
parent d8389ad760
commit 5b2db97703

View File

@ -2003,6 +2003,130 @@ static int o_get_last_ptr(o_string *o, int n)
return ((int)(ptrdiff_t)list[n-1]) + string_start;
}
#undef 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
/* Return pointer to next closing brace or to comma */
static const char *next_brace_sub(const char *cp)
{
unsigned depth = 0;
cp++;
while (*cp != '\0') {
if (*cp == '\\') {
if (*++cp == '\0')
break;
cp++;
continue;
}
/*{*/ if ((*cp == '}' && depth-- == 0) || (*cp == ',' && depth == 0))
break;
if (*cp++ == '{') /*}*/
depth++;
}
return *cp != '\0' ? cp : NULL;
}
static int glob_brace(const char *pattern, int flags, glob_t *pglob)
{
const char *begin;
char *alt_start;
const char *p;
const char *next;
const char *rest;
size_t rest_len;
char *onealt;
debug_printf_glob("glob_brace('%s')\n", pattern);
begin = pattern;
while (1) {
if (*begin == '\0')
goto do_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;
}
/*{*/ if (*next == '}') {
/* "{abc}" with no commas - illegal
* brace expr, disregard and skip it */
begin = next + 1;
continue;
}
break;
}
if (*begin == '\\' && begin[1] != '\0')
begin++;
begin++;
}
debug_printf_glob("begin:%s\n", begin);
debug_printf_glob("next:%s\n", next);
/* Now find the end of the whole brace expression */
rest = next;
/*{*/ while (*rest != '}') {
rest = next_brace_sub(rest);
if (rest == NULL) {
/* An illegal expression */
goto do_glob;
}
debug_printf_glob("rest:%s\n", rest);
}
rest_len = strlen(++rest) + 1;
/* 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);
/* We have a brace expression. BEGIN points to the opening {,
* NEXT points past the terminator of the first element, and REST
* points past the final }. We will accumulate result names from
* recursive runs for each brace alternative in the buffer using
* GLOB_APPEND. */
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;
/*{*/ if (*next == '}') {
/* We saw the last entry */
break;
}
p = next + 1;
next = next_brace_sub(next);
}
/* We found some entries */
return 0;
do_glob:
return glob(pattern, flags, NULL, pglob);
}
#endif
/* o_glob performs globbing on last list[], saving each result
* as a new list[]. */
static int o_glob(o_string *o, int n)
@ -2024,17 +2148,22 @@ static int o_glob(o_string *o, int n)
}
memset(&globdata, 0, sizeof(globdata));
//TODO: can use GLOB_BRACE | GLOB_TILDE here:
#ifdef HUSH_BRACE_EXP
gr = glob_brace(pattern, GLOB_NOCHECK, &globdata);
debug_printf_glob("glob_brace('%s'):%d\n", pattern, gr);
#else
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("out of memory during glob");
bb_error_msg_and_die(bb_msg_memory_exhausted);
if (gr == GLOB_NOMATCH) {
globfree(&globdata);
goto literal;
}
if (gr != 0) { /* GLOB_ABORTED ? */
/* TODO: testcase for bad glob pattern behavior */
if (gr != 0) {
/* 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);
}
if (globdata.gl_pathv && globdata.gl_pathv[0]) {