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

1 files changed, 14 insertions, 18 deletions

diff --git a/main/strcompat.c b/main/strcompat.c
index 03c304144..dcd84d876 100644
--- a/main/strcompat.c
+++ b/main/strcompat.c
@@ -68,12 +68,12 @@ int setenv(const char *name, const char *value, int overwrite)
 	unsigned char *buf;
 	int buflen;
 
-	buflen = strlen(name) + strlen(value) + 2;
-	buf = alloca(buflen);
-
 	if (!overwrite && getenv(name))
 		return 0;
 
+	buflen = strlen(name) + strlen(value) + 2;
+	buf = ast_alloca(buflen);
+
 	snprintf(buf, buflen, "%s=%s", name, value);
 
 	return putenv(buf);
@@ -105,23 +105,19 @@ static char *upper(const char *orig, char *buf, int bufsize)
 char *strcasestr(const char *haystack, const char *needle)
 {
 	char *u1, *u2;
+	char *offset;
 	int u1len = strlen(haystack) + 1, u2len = strlen(needle) + 1;
 
-	u1 = alloca(u1len);
-	u2 = alloca(u2len);
-	if (u1 && u2) {
-		char *offset;
-		if (u2len > u1len) {
-			/* Needle bigger than haystack */
-			return NULL;
-		}
-		offset = strstr(upper(haystack, u1, u1len), upper(needle, u2, u2len));
-		if (offset) {
-			/* Return the offset into the original string */
-			return ((char *)((unsigned long)haystack + (unsigned long)(offset - u1)));
-		} else {
-			return NULL;
-		}
+	if (u2len > u1len) {
+		/* Needle bigger than haystack */
+		return NULL;
+	}
+	u1 = ast_alloca(u1len);
+	u2 = ast_alloca(u2len);
+	offset = strstr(upper(haystack, u1, u1len), upper(needle, u2, u2len));
+	if (offset) {
+		/* Return the offset into the original string */
+		return ((char *)((unsigned long)haystack + (unsigned long)(offset - u1)));
 	} else {
 		return NULL;
 	}