Clean up and ensure proper usage of alloca()

This replaces all calls to alloca() with ast_alloca() which calls gcc's
__builtin_alloca() to avoid BSD semantics and removes all NULL checks
on memory allocated via ast_alloca() and ast_strdupa().

(closes issue ASTERISK-20125)
Review: https://reviewboard.asterisk.org/r/2032/
Patch-by: Walter Doekes (wdoekes)
........

Merged revisions 370642 from http://svn.asterisk.org/svn/asterisk/branches/1.8
........

Merged revisions 370643 from http://svn.asterisk.org/svn/asterisk/branches/10


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@370655 65c4cc65-6c06-0410-ace0-fbb531ad65f3

5 files changed, 24 insertions, 26 deletions

diff --git a/funcs/func_channel.c b/funcs/func_channel.c
index 699f3b660..bd3367df2 100644
--- a/funcs/func_channel.c
+++ b/funcs/func_channel.c
@@ -684,7 +684,7 @@ static int func_mchan_read(struct ast_channel *chan, const char *function,
 			     char *data, struct ast_str **buf, ssize_t len)
 {
 	struct ast_channel *mchan = ast_channel_get_by_name(ast_channel_linkedid(chan));
-	char *template = alloca(4 + strlen(data));
+	char *template = ast_alloca(4 + strlen(data));
 	sprintf(template, "${%s}", data); /* SAFE */
 	ast_str_substitute_variables(buf, len, mchan ? mchan : chan, template);
 	if (mchan) {
diff --git a/funcs/func_cut.c b/funcs/func_cut.c
index 762dd61fe..4b6dc9d48 100644
--- a/funcs/func_cut.c
+++ b/funcs/func_cut.c
@@ -119,7 +119,7 @@ static int sort_internal(struct ast_channel *chan, char *data, char *buffer, siz
 			count++;
 	}
 
-	sortable_keys = alloca(count * sizeof(struct sortable_keys));
+	sortable_keys = ast_alloca(count * sizeof(struct sortable_keys));
 
 	memset(sortable_keys, 0, count * sizeof(struct sortable_keys));
 
@@ -170,9 +170,8 @@ static int cut_internal(struct ast_channel *chan, char *data, struct ast_str **b
 	/* Check arguments */
 	if (args.argc < 3) {
 		return ERROR_NOARG;
-	} else if (!(var_expr = alloca(strlen(args.varname) + 4))) {
-		return ERROR_NOMEM;
 	}
+	var_expr = ast_alloca(strlen(args.varname) + 4);
 
 	/* Get the value of the variable named in the 1st argument */
 	snprintf(var_expr, strlen(args.varname) + 4, "${%s}", args.varname);
diff --git a/funcs/func_global.c b/funcs/func_global.c
index e16b60ac1..0a4b89dae 100644
--- a/funcs/func_global.c
+++ b/funcs/func_global.c
@@ -148,7 +148,7 @@ static int shared_read(struct ast_channel *chan, const char *cmd, char *data, ch
 	AST_STANDARD_APP_ARGS(args, data);
 
 	if (!ast_strlen_zero(args.chan)) {
-		char *prefix = alloca(strlen(args.chan) + 2);
+		char *prefix = ast_alloca(strlen(args.chan) + 2);
 		sprintf(prefix, "%s-", args.chan);
 		if (!(c_ref = ast_channel_get_by_name(args.chan)) && !(c_ref = ast_channel_get_by_name_prefix(prefix, strlen(prefix)))) {
 			ast_log(LOG_ERROR, "Channel '%s' not found!  Variable '%s' will be blank.\n", args.chan, args.var);
@@ -206,7 +206,7 @@ static int shared_write(struct ast_channel *chan, const char *cmd, char *data, c
 	AST_STANDARD_APP_ARGS(args, data);
 
 	if (!ast_strlen_zero(args.chan)) {
-		char *prefix = alloca(strlen(args.chan) + 2);
+		char *prefix = ast_alloca(strlen(args.chan) + 2);
 		sprintf(prefix, "%s-", args.chan);
 		if (!(c_ref = ast_channel_get_by_name(args.chan)) && !(c_ref = ast_channel_get_by_name_prefix(prefix, strlen(prefix)))) {
 			ast_log(LOG_ERROR, "Channel '%s' not found!  Variable '%s' not set to '%s'.\n", args.chan, args.var, value);
diff --git a/funcs/func_logic.c b/funcs/func_logic.c
index 21f08a13f..e371f7ec1 100644
--- a/funcs/func_logic.c
+++ b/funcs/func_logic.c
@@ -250,17 +250,15 @@ static int import_helper(struct ast_channel *chan, const char *cmd, char *data,
 		struct ast_channel *chan2;
 
 		if ((chan2 = ast_channel_get_by_name(args.channel))) {
-			char *s = alloca(strlen(args.varname) + 4);
-			if (s) {
-				sprintf(s, "${%s}", args.varname);
-				ast_channel_lock(chan2);
-				if (buf) {
-					pbx_substitute_variables_helper(chan2, s, buf, len);
-				} else {
-					ast_str_substitute_variables(str, len, chan2, s);
-				}
-				ast_channel_unlock(chan2);
+			char *s = ast_alloca(strlen(args.varname) + 4);
+			sprintf(s, "${%s}", args.varname);
+			ast_channel_lock(chan2);
+			if (buf) {
+				pbx_substitute_variables_helper(chan2, s, buf, len);
+			} else {
+				ast_str_substitute_variables(str, len, chan2, s);
 			}
+			ast_channel_unlock(chan2);
 			chan2 = ast_channel_unref(chan2);
 		}
 	}
diff --git a/funcs/func_strings.c b/funcs/func_strings.c
index 5bf687b52..2ba1d535b 100644
--- a/funcs/func_strings.c
+++ b/funcs/func_strings.c
@@ -456,7 +456,7 @@ static int function_fieldqty_helper(struct ast_channel *chan, const char *cmd,
 	if (args.delim) {
 		ast_get_encoded_char(args.delim, delim, &delim_used);
 
-		varsubst = alloca(strlen(args.varname) + 4);
+		varsubst = ast_alloca(strlen(args.varname) + 4);
 
 		sprintf(varsubst, "${%s}", args.varname);
 		ast_str_substitute_variables(&str, 0, chan, varsubst);
@@ -522,7 +522,7 @@ static int function_fieldnum_helper(struct ast_channel *chan, const char *cmd,
 		ast_log(LOG_ERROR, "Usage: FIELDNUM(<listname>,<delimiter>,<fieldvalue>)\n");
 		res = -1;
 	} else {
-		varsubst = alloca(strlen(args.varname) + 4);
+		varsubst = ast_alloca(strlen(args.varname) + 4);
 		sprintf(varsubst, "${%s}", args.varname);
 
 		ast_str_substitute_variables(&str, 0, chan, varsubst);
@@ -606,7 +606,7 @@ static int listfilter(struct ast_channel *chan, const char *cmd, char *parse, ch
 		return -1;
 	}
 
-	varsubst = alloca(strlen(args.listname) + 4);
+	varsubst = ast_alloca(strlen(args.listname) + 4);
 	sprintf(varsubst, "${%s}", args.listname);
 
 	/* If we don't lock the channel, the variable could disappear out from underneath us. */
@@ -636,7 +636,7 @@ static int listfilter(struct ast_channel *chan, const char *cmd, char *parse, ch
 	}
 
 	dlen = strlen(args.delimiter);
-	delim = alloca(dlen + 1);
+	delim = ast_alloca(dlen + 1);
 	ast_get_encoded_str(args.delimiter, delim, dlen + 1);
 
 	if ((dlen = strlen(delim)) == 0) {
@@ -819,7 +819,7 @@ static int replace(struct ast_channel *chan, const char *cmd, char *data, struct
 		return -1;
 	}
 
-	varsubst = alloca(strlen(args.varname) + 4);
+	varsubst = ast_alloca(strlen(args.varname) + 4);
 	sprintf(varsubst, "${%s}", args.varname);
 	ast_str_substitute_variables(&str, 0, chan, varsubst);
 
@@ -906,7 +906,7 @@ static int strreplace(struct ast_channel *chan, const char *cmd, char *data, str
 	find_size = strlen(args.find_string);
 
 	/* set varsubstr to the matching variable */
-	varsubstr = alloca(strlen(args.varname) + 4);
+	varsubstr = ast_alloca(strlen(args.varname) + 4);
 	sprintf(varsubstr, "${%s}", args.varname);
 	ast_str_substitute_variables(&str, 0, chan, varsubstr);
 
@@ -1026,9 +1026,10 @@ static int array(struct ast_channel *chan, const char *cmd, char *var,
 	char *origvar = "", *value2, varname[256];
 	int i, ishash = 0;
 
-	value2 = ast_strdupa(value);
-	if (!var || !value2)
+	if (!var) {
 		return -1;
+	}
+	value2 = ast_strdupa(value);
 
 	if (!strcmp(cmd, "HASH")) {
 		const char *var2 = pbx_builtin_getvar_helper(chan, "~ODBCFIELDS~");
@@ -1544,7 +1545,7 @@ static int shift_pop(struct ast_channel *chan, const char *cmd, char *data, stru
 		return -1;
 	}
 
-	varsubst = alloca(strlen(args.var) + 4);
+	varsubst = ast_alloca(strlen(args.var) + 4);
 	sprintf(varsubst, "${%s}", args.var);
 	ast_str_substitute_variables(&before, 0, chan, varsubst);
 
@@ -1608,7 +1609,7 @@ static int unshift_push(struct ast_channel *chan, const char *cmd, char *data, c
 		ast_get_encoded_char(args.delimiter, delimiter, &unused);
 	}
 
-	varsubst = alloca(strlen(args.var) + 4);
+	varsubst = ast_alloca(strlen(args.var) + 4);
 	sprintf(varsubst, "${%s}", args.var);
 	ast_str_substitute_variables(&previous_value, 0, chan, varsubst);