common: command: Add support for $ auto-completion

Add the dollar_complete() function to auto-complete arguments starting
with a '$' and use it in the cmd_auto_complete() path such that all
args starting with a $ can be auto-completed based on the available env
vars.

Signed-off-by: Boris Brezillon <boris.brezillon@bootlin.com>
[trini: Fix some linking problems]
Signed-off-by: Tom Rini <trini@konsulko.com>

common/command.c

@@ -142,23 +142,38 @@ int cmd_usage(const cmd_tbl_t *cmdtp)
 }
 
 #ifdef CONFIG_AUTO_COMPLETE
+static char env_complete_buf[512];
 
 int var_complete(int argc, char * const argv[], char last_char, int maxv, char *cmdv[])
 {
-	static char tmp_buf[512];
 	int space;
 
 	space = last_char == '\0' || isblank(last_char);
 
 	if (space && argc == 1)
-		return env_complete("", maxv, cmdv, sizeof(tmp_buf), tmp_buf);
+		return env_complete("", maxv, cmdv, sizeof(env_complete_buf),
+				    env_complete_buf, false);
 
 	if (!space && argc == 2)
-		return env_complete(argv[1], maxv, cmdv, sizeof(tmp_buf), tmp_buf);
+		return env_complete(argv[1], maxv, cmdv,
+				    sizeof(env_complete_buf),
+				    env_complete_buf, false);
 
 	return 0;
 }
 
+static int dollar_complete(int argc, char * const argv[], char last_char,
+			   int maxv, char *cmdv[])
+{
+	/* Make sure the last argument starts with a $. */
+	if (argc < 1 || argv[argc - 1][0] != '$' ||
+	    last_char == '\0' || isblank(last_char))
+		return 0;
+
+	return env_complete(argv[argc - 1], maxv, cmdv, sizeof(env_complete_buf),
+			    env_complete_buf, true);
+}
+
 /*************************************************************************************/
 
 int complete_subcmdv(cmd_tbl_t *cmdtp, int count, int argc,
@@ -357,9 +372,14 @@ int cmd_auto_complete(const char *const prompt, char *buf, int *np, int *colp)
 	/* separate into argv */
 	argc = make_argv(tmp_buf, sizeof(argv)/sizeof(argv[0]), argv);
 
-	/* do the completion and return the possible completions */
-	i = complete_cmdv(argc, argv, last_char,
-			  sizeof(cmdv) / sizeof(cmdv[0]), cmdv);
+	/* first try a $ completion */
+	i = dollar_complete(argc, argv, last_char,
+			    sizeof(cmdv) / sizeof(cmdv[0]), cmdv);
+	if (!i) {
+		/* do the completion and return the possible completions */
+		i = complete_cmdv(argc, argv, last_char,
+				  sizeof(cmdv) / sizeof(cmdv[0]), cmdv);
+	}
 
 	/* no match; bell and out */
 	if (i == 0) {

env/common.c

@@ -240,32 +240,76 @@ void env_relocate(void)
 	}
 }
 
-#if defined(CONFIG_AUTO_COMPLETE) && !defined(CONFIG_SPL_BUILD)
-int env_complete(char *var, int maxv, char *cmdv[], int bufsz, char *buf)
+#ifdef CONFIG_AUTO_COMPLETE
+int env_complete(char *var, int maxv, char *cmdv[], int bufsz, char *buf,
+		 bool dollar_comp)
 {
 	ENTRY *match;
 	int found, idx;
 
+	if (dollar_comp) {
+		/*
+		 * When doing $ completion, the first character should
+		 * obviously be a '$'.
+		 */
+		if (var[0] != '$')
+			return 0;
+
+		var++;
+
+		/*
+		 * The second one, if present, should be a '{', as some
+		 * configuration of the u-boot shell expand ${var} but not
+		 * $var.
+		 */
+		if (var[0] == '{')
+			var++;
+		else if (var[0] != '\0')
+			return 0;
+	}
+
 	idx = 0;
 	found = 0;
 	cmdv[0] = NULL;
 
+
 	while ((idx = hmatch_r(var, idx, &match, &env_htab))) {
 		int vallen = strlen(match->key) + 1;
 
-		if (found >= maxv - 2 || bufsz < vallen)
+		if (found >= maxv - 2 ||
+		    bufsz < vallen + (dollar_comp ? 3 : 0))
 			break;
 
 		cmdv[found++] = buf;
+
+		/* Add the '${' prefix to each var when doing $ completion. */
+		if (dollar_comp) {
+			strcpy(buf, "${");
+			buf += 2;
+			bufsz -= 3;
+		}
+
 		memcpy(buf, match->key, vallen);
 		buf += vallen;
 		bufsz -= vallen;
+
+		if (dollar_comp) {
+			/*
+			 * This one is a bit odd: vallen already contains the
+			 * '\0' character but we need to add the '}' suffix,
+			 * hence the buf - 1 here. strcpy() will add the '\0'
+			 * character just after '}'. buf is then incremented
+			 * to account for the extra '}' we just added.
+			 */
+			strcpy(buf - 1, "}");
+			buf++;
+		}
 	}
 
 	qsort(cmdv, found, sizeof(cmdv[0]), strcmp_compar);
 
 	if (idx)
-		cmdv[found++] = "...";
+		cmdv[found++] = dollar_comp ? "${...}" : "...";
 
 	cmdv[found] = NULL;
 	return found;

include/common.h

@@ -248,7 +248,8 @@ static inline int env_set_addr(const char *varname, const void *addr)
 }
 
 #ifdef CONFIG_AUTO_COMPLETE
-int env_complete(char *var, int maxv, char *cmdv[], int maxsz, char *buf);
+int env_complete(char *var, int maxv, char *cmdv[], int maxsz, char *buf,
+		 bool dollar_comp);
 #endif
 int get_env_id (void);
 

lib/Makefile

@@ -41,7 +41,6 @@ obj-y += ldiv.o
 obj-$(CONFIG_MD5) += md5.o
 obj-y += net_utils.o
 obj-$(CONFIG_PHYSMEM) += physmem.o
-obj-y += qsort.o
 obj-y += rc4.o
 obj-$(CONFIG_SUPPORT_EMMC_RPMB) += sha256.o
 obj-$(CONFIG_RBTREE)	+= rbtree.o
@@ -67,7 +66,6 @@ obj-$(CONFIG_$(SPL_)LZ4) += lz4_wrapper.o
 
 obj-$(CONFIG_LIBAVB) += libavb/
 
-obj-$(CONFIG_$(SPL_TPL_)SAVEENV) += qsort.o
 obj-$(CONFIG_$(SPL_TPL_)OF_LIBFDT) += libfdt/
 ifneq ($(CONFIG_$(SPL_TPL_)BUILD)$(CONFIG_$(SPL_TPL_)OF_PLATDATA),yy)
 obj-$(CONFIG_$(SPL_TPL_)OF_CONTROL) += fdtdec_common.o
@@ -80,6 +78,7 @@ obj-$(CONFIG_$(SPL_TPL_)HASH_SUPPORT) += crc16.o
 obj-$(CONFIG_SPL_NET_SUPPORT) += net_utils.o
 endif
 obj-$(CONFIG_ADDR_MAP) += addr_map.o
+obj-y += qsort.o
 obj-y += hashtable.o
 obj-y += errno.o
 obj-y += display_options.o