env: re-add support for auto-completion

Currently, only basic completion is supported (no globs), but this is
what we had previously.

Signed-off-by: Mike Frysinger <vapier@gentoo.org>

common/command.c

@@ -162,7 +162,6 @@ int cmd_usage(cmd_tbl_t *cmdtp)
 
 int var_complete(int argc, char * const argv[], char last_char, int maxv, char *cmdv[])
 {
-#if 0 /* need to reimplement */
 	static char tmp_buf[512];
 	int space;
 
@@ -173,7 +172,7 @@ int var_complete(int argc, char * const argv[], char last_char, int maxv, char *
 
 	if (!space && argc == 2)
 		return env_complete(argv[1], maxv, cmdv, sizeof(tmp_buf), tmp_buf);
-#endif
+
 	return 0;
 }
 

common/env_common.c

@@ -246,42 +246,32 @@ void env_relocate (void)
 	}
 }
 
-#if 0 /* need to reimplement - def CONFIG_AUTO_COMPLETE */
+#ifdef CONFIG_AUTO_COMPLETE
 int env_complete(char *var, int maxv, char *cmdv[], int bufsz, char *buf)
 {
-	int i, nxt, len, vallen, found;
-	const char *lval, *rval;
+	ENTRY *match;
+	int found, idx;
 
+	idx = 0;
 	found = 0;
 	cmdv[0] = NULL;
 
-	len = strlen(var);
-	/* now iterate over the variables and select those that match */
-	for (i=0; env_get_char(i) != '\0'; i=nxt+1) {
+	while ((idx = hmatch_r(var, idx, &match, &env_htab))) {
+		int vallen = strlen(match->key) + 1;
 
-		for (nxt=i; env_get_char(nxt) != '\0'; ++nxt)
-			;
-
-		lval = (char *)env_get_addr(i);
-		rval = strchr(lval, '=');
-		if (rval != NULL) {
-			vallen = rval - lval;
-			rval++;
-		} else
-			vallen = strlen(lval);
-
-		if (len > 0 && (vallen < len || memcmp(lval, var, len) != 0))
-			continue;
-
-		if (found >= maxv - 2 || bufsz < vallen + 1) {
-			cmdv[found++] = "...";
+		if (found >= maxv - 2 || bufsz < vallen)
 			break;
-		}
+
 		cmdv[found++] = buf;
-		memcpy(buf, lval, vallen); buf += vallen; bufsz -= vallen;
-		*buf++ = '\0'; bufsz--;
+		memcpy(buf, match->key, vallen);
+		buf += vallen;
+		bufsz -= vallen;
 	}
 
+	qsort(cmdv, found, sizeof(cmdv[0]), strcmp_compar);
+
+	if (idx)
+		cmdv[found++] = "...";
 	cmdv[found] = NULL;
 	return found;
 }

include/common.h

@@ -632,6 +632,7 @@ static inline IPaddr_t getenv_IPaddr (char *var)
 /* lib/qsort.c */
 void qsort(void *base, size_t nmemb, size_t size,
 	   int(*compar)(const void *, const void *));
+int strcmp_compar(const void *, const void *);
 
 /* lib/time.c */
 void	udelay        (unsigned long);

include/search.h

@@ -74,6 +74,13 @@ extern void hdestroy_r(struct hsearch_data *__htab);
 extern int hsearch_r(ENTRY __item, ACTION __action, ENTRY ** __retval,
 		     struct hsearch_data *__htab);
 
+/*
+ * Search for an entry matching `MATCH'.  Otherwise, Same semantics
+ * as hsearch_r().
+ */
+extern int hmatch_r(const char *__match, int __last_idx, ENTRY ** __retval,
+		    struct hsearch_data *__htab);
+
 /* Search and delete entry matching ITEM.key in internal hash table. */
 extern int hdelete_r(const char *__key, struct hsearch_data *__htab);
 

lib/hashtable.c

@@ -202,6 +202,26 @@ void hdestroy_r(struct hsearch_data *htab)
  *   example for functions like hdelete().
  */
 
+int hmatch_r(const char *match, int last_idx, ENTRY ** retval,
+	     struct hsearch_data *htab)
+{
+	unsigned int idx;
+	size_t key_len = strlen(match);
+
+	for (idx = last_idx + 1; idx < htab->size; ++idx) {
+		if (!htab->table[idx].used)
+			continue;
+		if (!strncmp(match, htab->table[idx].entry.key, key_len)) {
+			*retval = &htab->table[idx].entry;
+			return idx;
+		}
+	}
+
+	__set_errno(ESRCH);
+	*retval = NULL;
+	return 0;
+}
+
 int hsearch_r(ENTRY item, ACTION action, ENTRY ** retval,
 	      struct hsearch_data *htab)
 {

lib/qsort.c

@@ -16,6 +16,7 @@
  * bcc and gcc. */
 
 #include <linux/types.h>
+#include <exports.h>
 #if 0
 #include <assert.h>
 #else
@@ -67,3 +68,8 @@ void qsort(void  *base,
 		} while (wgap);
 	}
 }
+
+int strcmp_compar(const void *p1, const void *p2)
+{
+	return strcmp(*(const char **)p1, *(const char **)p2);
+}