Fix handling of negative return code when storing voicemails in ODBC storage

When storing a voicemail message using an ODBC connection to a database, the
voicemail message is first stored on disk.  The sound file associated with
the message is read into memory before being transmitted to the database.
When this occurs, a failure in the C library's lseek function would cause a
negative value to be passed to the mmap as the size of the memory map to
create.  This would almost certainly cause the creation of the memory map to
fail, resulting in the message being lost.

(issue ASTERISK-19655)
Reported by: Matt Jordan

Review: https://reviewboard.asterisk.org/r/1863

git-svn-id: https://origsvn.digium.com/svn/asterisk/branches/1.8@362201 65c4cc65-6c06-0410-ace0-fbb531ad65f3

apps/app_voicemail.c

@@ -3791,7 +3791,7 @@ static int store_file(const char *dir, const char *mailboxuser, const char *mail
 	int res = 0;
 	int fd = -1;
 	void *fdm = MAP_FAILED;
-	size_t fdlen = -1;
+	off_t fdlen = -1;
 	SQLHSTMT stmt;
 	char sql[PATH_MAX];
 	char msgnums[20];
@@ -3856,11 +3856,14 @@ static int store_file(const char *dir, const char *mailboxuser, const char *mail
 			}
 		}
 		fdlen = lseek(fd, 0, SEEK_END);
-		lseek(fd, 0, SEEK_SET);
+		if (fdlen < 0 || lseek(fd, 0, SEEK_SET) < 0) {
-		printf("Length is %zd\n", fdlen);
+			ast_log(AST_LOG_WARNING, "Failed to process sound file '%s': %s\n", full_fn, strerror(errno));
+			res = -1;
+			break;
+		}
 		fdm = mmap(NULL, fdlen, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
 		if (fdm == MAP_FAILED) {
-			ast_log(AST_LOG_WARNING, "Memory map failed!\n");
+			ast_log(AST_LOG_WARNING, "Memory map failed for sound file '%s'!\n", full_fn);
 			res = -1;
 			break;
 		} 
@@ -4102,8 +4105,7 @@ static int copy(char *infile, char *outfile)
 				close(ifd);
 				close(ofd);
 				unlink(outfile);
-			}
+			} else if (len) {
-			if (len) {
 				res = write(ofd, buf, len);
 				if (errno == ENOMEM || errno == ENOSPC || res != len) {
 					ast_log(AST_LOG_WARNING, "Write failed on %s (%d of %d): %s\n", outfile, res, len, strerror(errno));