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

@@ -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);
 }
 

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);