Fix gcc 8.1.1 compiler warnings

    CC ../shared.o
../shared.c: In function ‘expand_macro’:
../shared.c:487:3: warning: ‘strncpy’ specified bound depends on the length of the source argument [-Wstringop-overflow=]
   strncpy(name, value, len);
   ^~~~~~~~~~~~~~~~~~~~~~~~~
../shared.c:484:9: note: length computed here
   len = strlen(value);
         ^~~~~~~~~~~~~
../ui-shared.c: In function ‘cgit_repobasename’:
../ui-shared.c:136:2: warning: ‘strncpy’ specified bound 1024 equals destination size [-Wstringop-truncation]
  strncpy(rvbuf, reponame, sizeof(rvbuf));
  ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    CC ../ui-ssdiff.o
../ui-ssdiff.c: In function ‘replace_tabs’:
../ui-ssdiff.c:142:4: warning: ‘strncat’ output truncated copying between 1 and 8 bytes from a string of length 8 [-Wstringop-truncation]
    strncat(result, spaces, 8 - (strlen(result) % 8));
    ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>

1 files changed, 4 insertions, 3 deletions

diff --git a/shared.c b/shared.c

index f7b64cf..609bd2a 100644
--- a/shared.c
+++ b/shared.c
@@ -476,15 +476,16 @@ static int is_token_char(char c)
 static char *expand_macro(char *name, int maxlength)
 {
 	char *value;
-	int len;
+	size_t len;
 
 	len = 0;
 	value = getenv(name);
 	if (value) {
-		len = strlen(value);
+		len = strlen(value) + 1;
 		if (len > maxlength)
 			len = maxlength;
-		strncpy(name, value, len);
+		strlcpy(name, value, len);
+		--len;
 	}
 	return name + len;
 }