From 77ebaecf895b8b863e3e80382bd6ec0e18305dcd Mon Sep 17 00:00:00 2001
From: chatty
Date: Tue, 27 Jul 1993 13:51:56 +0000
Subject: Incorporated changes from mbl@prl and mbl@europarc

---
 comm/error.cc | 118 +++++++++++++++++++++++++++++++++++++++++++++++++++++-----
 1 file changed, 108 insertions(+), 10 deletions(-)

(limited to 'comm/error.cc')

diff --git a/comm/error.cc b/comm/error.cc
index fc02eb9..aed7c0b 100644
--- a/comm/error.cc
+++ b/comm/error.cc
@@ -17,7 +17,12 @@
 #include <stdlib.h>
 #include <string.h>
 #include <unistd.h>
+#ifdef sun
+extern "C" int rename (const char*, const char*);
+#endif
 #include <stdio.h>
+#include <sys/file.h>
+#include "ccu/Time.h"
 
 /*?class UchERROR
 The set of global functions described here are designed to handle errors.
@@ -60,8 +65,13 @@ char* ErrorTable [] = {
 	"Subclass should implement virtual member",	// ErrShouldImplement
 };
 
-static char ProgName [128], LogFile [128];
+static char ProgName [256], LogFile [256];
 static bool LogOn =FALSE;
+static int  LogFd = -1;
+static off_t LogSize = 0;
+static off_t LogHalf = 0;
+
+#define LOG_HALF	25000
 
 static errtype
 DefaultHandler (errtype how, const char* /*who*/, const char* /*what*/, const char* msg)
@@ -82,7 +92,7 @@ HandleError (errtype how, const char* who, const char* what)
 	
 	char *msg = MakeErrorString (how, who, what);
 	
-	if (how >= ErrLog && LogOn) {
+	if (how >= ErrLog) {
 		LogMessage (msg);
 		if (how == ErrLog)
 			return TRUE;
@@ -133,20 +143,77 @@ ProgramName (const char* name)
 /*?
 Set the log file name.
 All messages are appended to the logfile.
-If \var{reset} is TRUE, the file is cleared.
-NOTE : logging is not currently implemented.
+If \var{reset} is TRUE, the file is renamed to \var{file\~}.
+If this fails, the file is simply cleared.
+If the \com{LOGDIR} environment variable is defined, and if \var{file}
+does not start with \com{/} or \com{./}, the value of \com{LOGDIR} is
+prepended to \var{file}, followed by a slash if necessary.
+Otherwise, the directory \com{$HOME/.log} is used.
 ?*/
 void
 LogfileName (const char* file, bool reset)
 {
 	if (file) {
-		strncpy (LogFile, file, sizeof (LogFile) -1);
+		if (LogOn && LogFd >= 0)
+			close (LogFd);
+		if (*file == '/' || strncmp (file, "./", 2) == 0) {
+			LogFile [0] = '\0';
+		} else {
+			// try $LOGDIR
+			char* dir = getenv ("LOGDIR");
+			if (dir) {
+				strcpy (LogFile, dir);
+			} else {
+				// try $HOME/.log
+				char* home = getenv ("HOME");
+				if (home) {
+					strcpy (LogFile, home);
+					strcat (LogFile, "/.log");
+					if (access (LogFile, F_OK) != 0) {
+						// try to create the directory
+						if (mkdir (LogFile, 0755) != 0) {
+							Error (ErrWarn, "LogFileName", "logging to /tmp directory");
+							strcpy (LogFile, "/tmp");
+						}
+					}
+				}
+			}
+			if (LogFile [strlen (LogFile) - 1] != '/')
+				strcat (LogFile, "/");
+		}
+			
+		strcat (LogFile, file);
 		LogOn = TRUE;
+		int flags = O_RDWR | O_CREAT;
 		if (reset) {
-			// to do: clear logfile
+			flags |= O_TRUNC;
+			// try to save previous version in LogFile~
+			if (access (LogFile, F_OK) == 0) {
+				char old [256];
+				strcpy (old, LogFile);
+				strcat (old, "~");
+				rename (LogFile, old);
+			}
+		}
+		LogFd = open (LogFile, flags, 0644);
+		if (LogFd < 0) {
+			SysError (ErrWarn, "LogfileName");
+			LogOn = FALSE;
+		} else {
+			LogHalf = 0;
+			if (reset)
+				LogSize = 0;
+			else {
+				LogSize = lseek (LogFd, 0L, 2 /*SEEK_END*/);
+				LogSize += write (LogFd, "\n", 1);
+			}
+			LogMessage ("-------- logging started --------\n");
 		}
-	} else
+	} else {
+		if (LogOn && LogFd >= 0)
+			close (LogFd);
 		LogOn = FALSE;
+	}
 }
 
 /*?nodoc?*/
@@ -158,12 +225,43 @@ CleanUp (CleanUpProc)
 
 /*?
 Append a message to the logfile, if one has been specified.
-NOTE : logging is not currently implemented.
 ?*/
 void
-LogMessage (const char*)
+LogMessage (const char* msg)
 {
-	// to be done
+	if (! LogOn || LogFd < 0)
+		return;
+
+	CcuTimeStamp now;
+	// format of time: Sun Sep 16 01:03:52 1973\n\0
+	//                 123456789012345678901234
+	LogSize += write (LogFd, now.AsString (), 20); // strip year 
+	LogSize += write (LogFd, msg, strlen (msg));
+	
+	// limit the size of the log file
+	if (LogSize > LOG_HALF && LogHalf == 0)
+		LogHalf = LogSize;
+	
+	if (LogSize < 2 * LOG_HALF)
+		return;
+	
+	// copy bytes from LogHalf to LogSize to beginning of file
+	off_t src, dst;
+	int n;
+	char buf [4096];
+	lseek (LogFd, 0L, 0 /*SEEK_SET*/);
+	write (LogFd, "...\n", 4);
+	for (src = LogHalf, dst = 4; src < LogSize; src += n, dst += n) {
+		lseek (LogFd, src, 0 /*SEEK_SET*/);
+		n = read (LogFd, buf, sizeof (buf));
+		if (n <= 0)
+			break;
+		lseek (LogFd, dst, 0 /*SEEK_SET*/);
+		write (LogFd, buf, n);
+	}
+	lseek (LogFd, dst, 0 /*SEEK_SET*/);
+//////	ftruncate (LogFd, dst); /////// this seems not to be a POSIX call
+	LogHalf = LogSize = dst;
 }
 
 /*?
-- 
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