From 10a9a05cd89ed234062b5464c41efc8b8c78ae79 Mon Sep 17 00:00:00 2001
From: James R <justsomejames2@gmail.com>
Date: Mon, 23 Dec 2019 18:20:04 -0800
Subject: [PATCH] symlink latest-log.txt on nix, copy to the real log file
 everywhere else

(cherry picked from commit 25525a6aae84581ac03ca3089950ad4ff25b8512)
---
 src/doomdef.h      |  1 +
 src/sdl/i_main.c   | 40 +++++++++++++++++++++++++++++-----------
 src/sdl/i_system.c | 45 +++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 75 insertions(+), 11 deletions(-)

diff --git a/src/doomdef.h b/src/doomdef.h
index bb21e3d0f..a3e473acc 100644
--- a/src/doomdef.h
+++ b/src/doomdef.h
@@ -138,6 +138,7 @@
 
 #ifdef LOGMESSAGES
 extern FILE *logstream;
+extern char logfilename[1024];
 #endif
 
 //#define DEVELOP // Disable this for release builds to remove excessive cheat commands and enable MD5 checking and stuff, all in one go. :3
diff --git a/src/sdl/i_main.c b/src/sdl/i_main.c
index 932861353..0550b8e02 100644
--- a/src/sdl/i_main.c
+++ b/src/sdl/i_main.c
@@ -23,10 +23,14 @@
 #include "../m_misc.h"/* path shit */
 #include "../i_system.h"
 
-#ifdef __GNUC__
+#if defined (__GNUC__) || defined (__unix__)
 #include <unistd.h>
 #endif
 
+#ifdef __unix__
+#include <errno.h>
+#endif
+
 #include "time.h" // For log timestamps
 
 #ifdef HAVE_SDL
@@ -48,6 +52,7 @@ extern int SDL_main(int argc, char *argv[]);
 
 #ifdef LOGMESSAGES
 FILE *logstream = NULL;
+char logfilename[1024];
 #endif
 
 #ifndef DOXYGEN
@@ -117,7 +122,6 @@ int main(int argc, char **argv)
 #endif
 {
 	const char *logdir = NULL;
-	char logfile[MAX_WADPATH];
 	myargc = argc;
 	myargv = argv; /// \todo pull out path to exe from this string
 
@@ -157,7 +161,7 @@ int main(int argc, char **argv)
 
 		if (fileabs)
 		{
-			strftime(logfile, sizeof logfile, format, timeinfo);
+			strftime(logfilename, sizeof logfilename, format, timeinfo);
 		}
 		else
 		{
@@ -168,32 +172,46 @@ int main(int argc, char **argv)
 
 			if (M_IsPathAbsolute(reldir))
 			{
-				left = snprintf(logfile, sizeof logfile,
+				left = snprintf(logfilename, sizeof logfilename,
 						"%s"PATHSEP, reldir);
 			}
 			else
 #ifdef DEFAULTDIR
 			if (logdir)
 			{
-				left = snprintf(logfile, sizeof logfile,
+				left = snprintf(logfilename, sizeof logfilename,
 						"%s"PATHSEP DEFAULTDIR PATHSEP"%s"PATHSEP, logdir, reldir);
 			}
 			else
 #endif/*DEFAULTDIR*/
 			{
-				left = snprintf(logfile, sizeof logfile,
+				left = snprintf(logfilename, sizeof logfilename,
 						"."PATHSEP"%s"PATHSEP, reldir);
 			}
 #endif/*LOGMESSAGES*/
 
-			strftime(&logfile[left], sizeof logfile - left, format, timeinfo);
+			strftime(&logfilename[left], sizeof logfilename - left,
+					format, timeinfo);
 		}
 
-		M_MkdirEachUntil(logfile,
+		M_MkdirEachUntil(logfilename,
 				M_PathParts(logdir) - 1,
-				M_PathParts(logfile) - 1, 0755);
+				M_PathParts(logfilename) - 1, 0755);
 
-		logstream = fopen(logfile, "wt");
+#ifdef __unix__
+		logstream = fopen(logfilename, "w");
+#ifdef DEFAULTDIR
+		if (symlink(logfilename,
+					va("%s/"DEFAULTDIR"/latest-log.txt", logdir)) == -1)
+#else
+		if (symlink(logfilename, va("%s/latest-log.txt", logdir)) == -1)
+#endif/*DEFAULTDIR*/
+		{
+			I_OutputMsg("Error symlinking latest-log.txt: %s\n", strerror(errno));
+		}
+#else/*__unix__*/
+		logstream = fopen("latest-log.txt", "wt+");
+#endif/*__unix__*/
 	}
 
 	//I_OutputMsg("I_StartupSystem() ...\n");
@@ -222,7 +240,7 @@ int main(int argc, char **argv)
 	D_SRB2Main();
 #ifdef LOGMESSAGES
 	if (!M_CheckParm("-nolog"))
-		CONS_Printf("Logfile: %s\n", logfile);
+		CONS_Printf("Logfile: %s\n", logfilename);
 #endif
 	CONS_Printf("Entering main game loop...\n");
 	// never return
diff --git a/src/sdl/i_system.c b/src/sdl/i_system.c
index f75a42117..2ccdec5c4 100644
--- a/src/sdl/i_system.c
+++ b/src/sdl/i_system.c
@@ -3268,6 +3268,48 @@ void I_RemoveExitFunc(void (*func)())
 	}
 }
 
+#ifndef __unix__
+static void Shittycopyerror(const char *name)
+{
+	I_OutputMsg(
+			"Error copying log file: %s: %s\n",
+			name,
+			strerror(errno)
+	);
+}
+
+static void Shittylogcopy(void)
+{
+	char buf[8192];
+	FILE *fp;
+	int n;
+	if (fseek(logstream, 0, SEEK_SET) == -1)
+	{
+		Shittycopyerror("fseek");
+	}
+	else if (( fp = fopen(logfilename, "wt") ))
+	{
+		while (( n = fread(buf, 1, sizeof buf, logstream) ))
+		{
+			if (fwrite(buf, 1, n, fp) < n)
+			{
+				Shittycopyerror("fwrite");
+				break;
+			}
+		}
+		if (ferror(logstream))
+		{
+			Shittycopyerror("fread");
+		}
+		fclose(fp);
+	}
+	else
+	{
+		Shittycopyerror(logfilename);
+	}
+}
+#endif/*__unix__*/
+
 //
 //  Closes down everything. This includes restoring the initial
 //  palette and video mode, and removing whatever mouse, keyboard, and
@@ -3286,6 +3328,9 @@ void I_ShutdownSystem(void)
 	if (logstream)
 	{
 		I_OutputMsg("I_ShutdownSystem(): end of logstream.\n");
+#ifndef __unix__
+		Shittylogcopy();
+#endif
 		fclose(logstream);
 		logstream = NULL;
 	}