From a03343c2acbc382a59a176713d5e33387b82f6a9 Mon Sep 17 00:00:00 2001
From: Daris A Nevil <daris@nevil.org>
Date: Tue, 18 Feb 2020 14:26:06 +0000
Subject: [PATCH] Remove 8K limit for single access.log line (#332)

The function logfilePrintf() currently limits a single line
to no more than 8K characters.  It allocates an 8K buffer
on the stack, which is not safe. This PR eliminates
the 8K limit, and moves the buffer to the heap.
---
 src/log/File.cc | 21 ++++++---------------
 src/log/File.h  |  2 +-
 2 files changed, 7 insertions(+), 16 deletions(-)

diff --git a/src/log/File.cc b/src/log/File.cc
index 42a873909c9..36cf4ca3c4d 100644
--- a/src/log/File.cc
+++ b/src/log/File.cc
@@ -17,6 +17,7 @@
 #include "log/ModSyslog.h"
 #include "log/ModUdp.h"
 #include "log/TcpLogger.h"
+#include "sbuf/SBuf.h"
 
 CBDATA_CLASS_INIT(Logfile);
 
@@ -103,7 +104,7 @@ logfileRotate(Logfile * lf, int16_t rotateCount)
 }
 
 void
-logfileWrite(Logfile * lf, char *buf, size_t len)
+logfileWrite(Logfile * lf, const char *buf, size_t len)
 {
     lf->f_linewrite(lf, buf, len);
 }
@@ -112,21 +113,11 @@ void
 logfilePrintf(Logfile * lf, const char *fmt,...)
 {
     va_list args;
-    char buf[8192];
-    int s;
-
     va_start(args, fmt);
-
-    s = vsnprintf(buf, 8192, fmt, args);
-
-    if (s > 8192) {
-        s = 8192;
-
-        if (fmt[strlen(fmt) - 1] == '\n')
-            buf[8191] = '\n';
-    }
-
-    logfileWrite(lf, buf, (size_t) s);
+    static SBuf sbuf;
+    sbuf.clear();
+    sbuf.vappendf(fmt, args); // Throws on overflow. TODO: handle that better
+    logfileWrite(lf, sbuf.c_str(), sbuf.length());
     va_end(args);
 }
 
diff --git a/src/log/File.h b/src/log/File.h
index cc4ff9c049a..5f034fb79ac 100644
--- a/src/log/File.h
+++ b/src/log/File.h
@@ -66,7 +66,7 @@ class Logfile
 Logfile *logfileOpen(const char *path, size_t bufsz, int);
 void logfileClose(Logfile * lf);
 void logfileRotate(Logfile * lf, int16_t rotateCount);
-void logfileWrite(Logfile * lf, char *buf, size_t len);
+void logfileWrite(Logfile * lf, const char *buf, size_t len);
 void logfileFlush(Logfile * lf);
 void logfilePrintf(Logfile * lf, const char *fmt,...) PRINTF_FORMAT_ARG2;
 void logfileLineStart(Logfile * lf);