From 8b2c7c224f3ff45c5404501034bdc2e01612eef0 Mon Sep 17 00:00:00 2001
From: Leo C <erbl259-lmu@yahoo.de>
Date: Thu, 26 Jul 2018 17:44:46 +0200
Subject: [PATCH] heap.c: Eliminate malloc/free in envlist_import() and
 _do_env_set()

---
 avr/env.c | 112 +++++++++++++++++++++++++++++++++++++++---------------
 1 file changed, 82 insertions(+), 30 deletions(-)

diff --git a/avr/env.c b/avr/env.c
index 1ec0c8e..6bbd99c 100644
--- a/avr/env.c
+++ b/avr/env.c
@@ -132,6 +132,55 @@ static char *envlist_search(const MEMX char *name)
 	return NULL;
 }
 
+static char *env_item_insert_name(char *pos, const char *name, int len)
+{
+	char *dstp = pos + len + 1;
+	char *end = pos;
+	while (*end++ != 0)
+		while (*end++ != 0);
+
+	if (end > env_list + ENV_SIZE)
+		return NULL;
+
+	memmove(dstp, pos, end - pos);
+	strcpy(pos, name);
+	memset(pos + strlen(name), '=', dstp - pos - strlen(name));
+	*(dstp - 1) = '\0';
+
+	return pos;
+}
+
+
+static char *envlist_alloc(const char *name, int len)
+{
+	char *lp;
+	int rc;
+
+
+	for (lp = env_list; *lp != 0; ++lp) {
+
+		rc = envcmp(lp, name);
+		if (rc >= 0)
+			break;
+
+		/* rc <  0 : check next place */
+		while (*lp != 0)
+			++lp;
+	}
+
+	/* rc == 0 : entry found, replace */
+	if (rc == 0)
+		env_item_delete(lp);
+
+	/* rc >  0 : entry not in list, insert */
+	/* *lp == 0 : entry not in list, insert */
+
+	lp = env_item_insert_name(lp, name, len);
+
+	return lp;
+}
+
+#if 0
 static char *env_item_insert(char *pos, const char *envstr)
 {
 	char *dstp = pos + strlen(envstr) + 1;
@@ -148,14 +197,11 @@ static char *env_item_insert(char *pos, const char *envstr)
 	return pos;
 }
 
-
 static char *envlist_enter(const char *ep)
 {
 	char *lp;
-	size_t len = strchr(ep, '=') - ep;
 	int rc;
 
-
 	for (lp = env_list; *lp != 0; ++lp) {
 
 		rc = envcmp(lp, ep);
@@ -178,7 +224,7 @@ static char *envlist_enter(const char *ep)
 
 	return lp;
 }
-
+#endif
 
 static
 int envlist_delete(const MEMX char *name)
@@ -194,31 +240,40 @@ int envlist_delete(const MEMX char *name)
 static
 int envlist_import(uint8_t flags)
 {
-	uint16_t index;
-	int len;
-	char *ep;
-
 	if ((flags & ENVLIST_DELETE) != 0)
 		envlist_clear();
 
-	for (index = 0; env_get_char(index) != '\0'; ) {
-		for (len = 0; env_get_char(index + len) != '\0'; ++len) {
+	for (uint_fast16_t index = 0; env_get_char(index) != '\0'; ) {
+		char name[CONFIG_SYS_ENV_NAMELEN+1];
+		uint_fast8_t nlen = 0;
+		size_t len;
+		char ch;
+		for (len = 0; (ch = env_get_char(index + len)) != '\0'; ++len) {
 			if ((index + len) >= ENV_SIZE)
 				return -1;
+			if (nlen == 0) {
+				if (ch == '=') {
+					nlen = len;
+					name[nlen] = '\0';
+				} else {
+					if (len > CONFIG_SYS_ENV_NAMELEN)
+						return -1;
+					name[len] = ch;
+				}
+			}
 		}
 
-		ep = (char *) malloc(len+1);
+		char *ep = envlist_alloc(name, len);
 		if (ep == NULL) {
-			printf_P(PSTR("## Can't malloc %d bytes\n"), len+1);
+			printf_P(PSTR("## Error inserting \"%s\" variable.\n"),	name);
 			return 1;
 		}
-		char *p = ep;
+
+		index += nlen;
+		char *p = ep + nlen;
 		while ((*p++ = env_get_char(index++)) != '\0')
 			;
-		envlist_enter(ep);
-		free(ep);
 	}
-
 	return 0;
 }
 
@@ -479,27 +534,24 @@ command_ret_t _do_env_set(uint_fast8_t flag UNUSED, int argc, char * const argv[
 	}
 
 	/* Insert / replace new value */
-	len += 1;
+
 	for (int_fast8_t i = 2; i < argc; ++i)
 		len += strlen(argv[i]) + 1;
 
-	char *envstr = malloc(len);
-	if (envstr == NULL) {
-		printf_P(PSTR("## Can't malloc %d bytes\n"), len);
+	char *pos = envlist_alloc(name, len);
+	if (pos == NULL) {
+		printf_P(PSTR("## Error inserting \"%s\" variable.\n"),	name);
 		return CMD_RET_FAILURE;
 	}
-	strcpy(envstr, name);
-	strcat_P(envstr, PSTR("="));
-	for (int_fast8_t i = 2; i < argc; ++i) {
-		strcat(envstr, argv[i]);
-		if (i < argc-1)
-			strcat_P(envstr, PSTR(" "));
-	}
 
-	if (envlist_enter(envstr) == NULL) {
-		printf_P(PSTR("## Error inserting \"%s\" variable.\n"),	name);
-		return CMD_RET_FAILURE;
+	char *vp = pos + strlen(name) + 1;
+	for (int_fast8_t i = 2; i < argc; ++i) {
+		char *ap = argv[i];
+		while ((*vp++ = *ap++) != '\0');
+		//if (i < argc-1)
+		*(vp-1) = ' ';
 	}
+	*(vp-1) = '\0';
 
 	return CMD_RET_SUCCESS;
 }
-- 
2.39.2