[U-Boot] [PATCH] fix redundant environment for serial flash

[thomas.langer at lantiq.com]

This patch fixes problems in the handling of redundant environment in env_sf.c

The major problem are double calls of free() on the allocated buffers,
which damages the internal data of malloc and crashes on next call.

In addition, the selection of the active environment had errors and compiler 
warnings, which are corrected by this patch.

Signed-off-by: Thomas Langer <thomas.langer at lantiq.com>
---
This patch is done and tested against the version 2010.12 and 
applies also cleanly against the u-boot/master.

--- a/common/env_sf.c
+++ b/common/env_sf.c
@@ -59,7 +59,6 @@ DECLARE_GLOBAL_DATA_PTR;
 extern uchar default_environment[];
 
 char * env_name_spec = "SPI Flash";
-env_t *env_ptr;
 
 static struct spi_flash *env_flash;
 
@@ -79,7 +78,7 @@ int saveenv(void)
 	char	*saved_buffer = NULL;
 	u32	sector = 1;
 	int	ret;
-	char	flag = OBSOLETE_FLAG, new_flag = ACTIVE_FLAG;
+	char	flag = OBSOLETE_FLAG;
 
 	if (!env_flash) {
 		env_flash = spi_flash_probe(CONFIG_ENV_SPI_BUS,
@@ -159,7 +158,7 @@ int saveenv(void)
 
 	gd->env_valid = (gd->env_valid == 2 ? 1 : 2);
 
-	printf("Valid environment: %d\n", gd->env_valid);
+	printf("Valid environment: %d\n", (int)gd->env_valid);
 
  done:
 	if (saved_buffer)
@@ -174,25 +173,20 @@ void env_relocate_spec(void)
 	env_t *tmp_env1 = NULL;
 	env_t *tmp_env2 = NULL;
 	env_t *ep = NULL;
-	uchar flag1, flag2;
-	/* current_env is set only in case both areas are valid! */
-	int current_env = 0;
 
 	tmp_env1 = (env_t *)malloc(CONFIG_ENV_SIZE);
 	tmp_env2 = (env_t *)malloc(CONFIG_ENV_SIZE);
 
 	if (!tmp_env1 || !tmp_env2) {
-		free(tmp_env1);
-		free(tmp_env2);
 		set_default_env("!malloc() failed");
-		return;
+		goto out;
 	}
 
 	env_flash = spi_flash_probe(CONFIG_ENV_SPI_BUS, CONFIG_ENV_SPI_CS,
 			CONFIG_ENV_SPI_MAX_HZ, CONFIG_ENV_SPI_MODE);
 	if (!env_flash) {
 		set_default_env("!spi_flash_probe() failed");
-		return;
+		goto out;
 	}
 
 	ret = spi_flash_read(env_flash, CONFIG_ENV_OFFSET,
@@ -204,33 +198,30 @@ void env_relocate_spec(void)
 
 	if (crc32(0, tmp_env1->data, ENV_SIZE) == tmp_env1->crc)
 		crc1_ok = 1;
-	flag1 = tmp_env1->flags;
 
 	ret = spi_flash_read(env_flash, CONFIG_ENV_OFFSET_REDUND,
 				CONFIG_ENV_SIZE, tmp_env2);
 	if (!ret) {
 		if (crc32(0, tmp_env2->data, ENV_SIZE) == tmp_env2->crc)
 			crc2_ok = 1;
-		flag2 = tmp_env2->flags;
 	}
 
 	if (!crc1_ok && !crc2_ok) {
-		free(tmp_env1);
-		free(tmp_env2);
 		set_default_env("!bad CRC");
-		return;
+		goto err_read;
 	} else if (crc1_ok && !crc2_ok) {
 		gd->env_valid = 1;
-		ep = tmp_env1;
 	} else if (!crc1_ok && crc2_ok) {
+		gd->env_valid = 2;
+	} else if (tmp_env1->flags == ACTIVE_FLAG &&
+		   tmp_env2->flags == OBSOLETE_FLAG) {
 		gd->env_valid = 1;
-	} else if (flag1 == ACTIVE_FLAG && flag2 == OBSOLETE_FLAG) {
-		gd->env_valid = 1;
-	} else if (flag1 == OBSOLETE_FLAG && flag2 == ACTIVE_FLAG) {
+	} else if (tmp_env1->flags == OBSOLETE_FLAG &&
+		   tmp_env2->flags == ACTIVE_FLAG) {
 		gd->env_valid = 2;
-	} else if (flag1 == flag2) {
+	} else if (tmp_env1->flags == tmp_env2->flags) {
 		gd->env_valid = 2;
-	} else if (flag1 == 0xFF) {
+	} else if (tmp_env1->flags == 0xFF) {
 		gd->env_valid = 2;
 	} else {
 		/*
@@ -240,8 +231,6 @@ void env_relocate_spec(void)
 		gd->env_valid = 2;
 	}
 
-	free(env_ptr);
-
 	if (gd->env_valid == 1)
 		ep = tmp_env1;
 	else
@@ -257,10 +246,6 @@ err_read:
 	spi_flash_free(env_flash);
 	env_flash = NULL;
 out:
-	if (tmp_env1)
-		free(tmp_env1);
-	if (tmp_env2)
-		free(tmp_env2);
 	free(tmp_env1);
 	free(tmp_env2);