X-Git-Url: https://git.tokkee.org/?a=blobdiff_plain;f=strbuf.c;h=09c43ae59a7d4715c26f13d72ca37bc759d1c76d;hb=294e15fc19b5ba370b703d003920d000a4f5547a;hp=9b3c4457f229041784edfa65218aa09de7a5eff8;hpb=1b6d0ae58822ca35ce325dab978c35f0265f7227;p=git.git

diff --git a/strbuf.c b/strbuf.c
index 9b3c4457f..09c43ae59 100644
--- a/strbuf.c
+++ b/strbuf.c
@@ -30,8 +30,10 @@ void strbuf_init(struct strbuf *sb, size_t hint)
 {
 	sb->alloc = sb->len = 0;
 	sb->buf = strbuf_slopbuf;
-	if (hint)
+	if (hint) {
 		strbuf_grow(sb, hint);
+		sb->buf[0] = '\0';
+	}
 }
 
 void strbuf_release(struct strbuf *sb)
@@ -63,7 +65,8 @@ void strbuf_attach(struct strbuf *sb, void *buf, size_t len, size_t alloc)
 
 void strbuf_grow(struct strbuf *sb, size_t extra)
 {
-	if (sb->len + extra + 1 <= sb->len)
+	if (unsigned_add_overflows(extra, 1) ||
+	    unsigned_add_overflows(sb->len, extra + 1))
 		die("you want to use way too much memory");
 	if (!sb->alloc)
 		sb->buf = NULL;
@@ -152,7 +155,7 @@ int strbuf_cmp(const struct strbuf *a, const struct strbuf *b)
 void strbuf_splice(struct strbuf *sb, size_t pos, size_t len,
 				   const void *data, size_t dlen)
 {
-	if (pos + len < pos)
+	if (unsigned_add_overflows(pos, len))
 		die("you want to use way too much memory");
 	if (pos > sb->len)
 		die("`pos' is too far after the end of the buffer");
@@ -194,24 +197,29 @@ void strbuf_adddup(struct strbuf *sb, size_t pos, size_t len)
 
 void strbuf_addf(struct strbuf *sb, const char *fmt, ...)
 {
-	int len;
 	va_list ap;
+	va_start(ap, fmt);
+	strbuf_vaddf(sb, fmt, ap);
+	va_end(ap);
+}
+
+void strbuf_vaddf(struct strbuf *sb, const char *fmt, va_list ap)
+{
+	int len;
+	va_list cp;
 
 	if (!strbuf_avail(sb))
 		strbuf_grow(sb, 64);
-	va_start(ap, fmt);
-	len = vsnprintf(sb->buf + sb->len, sb->alloc - sb->len, fmt, ap);
-	va_end(ap);
+	va_copy(cp, ap);
+	len = vsnprintf(sb->buf + sb->len, sb->alloc - sb->len, fmt, cp);
+	va_end(cp);
 	if (len < 0)
-		die("your vsnprintf is broken");
+		die("BUG: your vsnprintf is broken (returned %d)", len);
 	if (len > strbuf_avail(sb)) {
 		strbuf_grow(sb, len);
-		va_start(ap, fmt);
 		len = vsnprintf(sb->buf + sb->len, sb->alloc - sb->len, fmt, ap);
-		va_end(ap);
-		if (len > strbuf_avail(sb)) {
-			die("this should not happen, your snprintf is broken");
-		}
+		if (len > strbuf_avail(sb))
+			die("BUG: your vsnprintf is broken (insatiable)");
 	}
 	strbuf_setlen(sb, sb->len + len);
 }