From c8401c591fac7fd98349e05e595cdbe861998a90 Mon Sep 17 00:00:00 2001
From: Laslo Hunhold <dev@frign.de>
Date: Mon, 5 Mar 2018 00:59:37 +0100
Subject: [PATCH] Add esnprintf() and refactor some code

The (size_t) discards the case where the return value of snprintf is < 0. This
is rather unlikely, but we'll keep it in mind anyway.
---
 http.c | 12 ++++++------
 util.c | 13 +++++++++++++
 util.h |  1 +
 3 files changed, 20 insertions(+), 6 deletions(-)

diff --git a/http.c b/http.c
index cf08ada..98dfb00 100644
--- a/http.c
+++ b/http.c
@@ -346,8 +346,8 @@ http_send_response(int fd, struct request *r)
 
 		/* if we have a vhost prefix, prepend it to the target */
 		if (s.vhost[i].prefix) {
-			if ((size_t)snprintf(realtarget, sizeof(realtarget), "%s%s",
-			    s.vhost[i].prefix, realtarget) >= sizeof(realtarget)) {
+			if (esnprintf(realtarget, sizeof(realtarget), "%s%s",
+			              s.vhost[i].prefix, realtarget)) {
 				return http_send_status(fd, S_REQUEST_TOO_LARGE);
 			}
 		}
@@ -363,8 +363,8 @@ http_send_response(int fd, struct request *r)
 			}
 
 			/* swap out target prefix */
-			if ((size_t)snprintf(tmptarget, sizeof(tmptarget), "%s%s",
-			    s.map[i].to, realtarget + len) >= sizeof(tmptarget)) {
+			if (esnprintf(tmptarget, sizeof(tmptarget), "%s%s",
+			              s.map[i].to, realtarget + len)) {
 				return http_send_status(fd, S_REQUEST_TOO_LARGE);
 			}
 			memcpy(realtarget, tmptarget, sizeof(realtarget));
@@ -441,8 +441,8 @@ http_send_response(int fd, struct request *r)
 
 	if (S_ISDIR(st.st_mode)) {
 		/* append docindex to target */
-		if ((size_t)snprintf(realtarget, sizeof(realtarget), "%s%s",
-		    r->target, s.docindex) >= sizeof(realtarget)) {
+		if (esnprintf(realtarget, sizeof(realtarget), "%s%s",
+		              r->target, s.docindex)) {
 			return http_send_status(fd, S_REQUEST_TOO_LARGE);
 		}
 
diff --git a/util.c b/util.c
index 1fe9db8..d3db040 100644
--- a/util.c
+++ b/util.c
@@ -61,6 +61,19 @@ timestamp(time_t t, char buf[TIMESTAMP_LEN])
 	return buf;
 }
 
+int
+esnprintf(char *str, size_t size, const char *fmt, ...)
+{
+	va_list ap;
+	int ret;
+
+	va_start(ap, fmt);
+	ret = vsnprintf(str, size, fmt, ap);
+	va_end(ap);
+
+	return (ret < 0 || (size_t)ret >= size);
+}
+
 #define	INVALID  1
 #define	TOOSMALL 2
 #define	TOOLARGE 3
diff --git a/util.h b/util.h
index 1f9e107..8408ce3 100644
--- a/util.h
+++ b/util.h
@@ -49,6 +49,7 @@ void die(const char *, ...);
 #define TIMESTAMP_LEN 30
 
 char *timestamp(time_t, char buf[TIMESTAMP_LEN]);
+int esnprintf(char *, size_t, const char *, ...);
 
 void *reallocarray(void *, size_t, size_t);
 long long strtonum(const char *, long long, long long, const char **);