-logdir lets the user change the log directory

src/m_misc.c

@@ -2453,3 +2453,76 @@ const char *M_FileError(FILE *fp)
 	else
 		return "end-of-file";
 }
+
+/** Return the number of parts of this path.
+*/
+int M_PathParts(const char *path)
+{
+	int n;
+	const char *p;
+	const char *t;
+	for (n = 0, p = path ;; ++n)
+	{
+		t = p;
+		if (( p = strchr(p, PATHSEP[0]) ))
+			p += strspn(p, PATHSEP);
+		else
+		{
+			if (*t)/* there is something after the final delimiter */
+				n++;
+			break;
+		}
+	}
+	return n;
+}
+
+/** Check whether a path is an absolute path.
+*/
+boolean M_IsPathAbsolute(const char *path)
+{
+#ifdef _WIN32
+	return ( strncmp(&path[1], ":\\", 2) == 0 );
+#else
+	return ( path[0] == '/' );
+#endif
+}
+
+/** I_mkdir for each part of the path.
+*/
+void M_MkdirEach(const char *cpath, int start, int mode)
+{
+	char path[MAX_WADPATH];
+	char *p;
+	char *t;
+	strlcpy(path, cpath, sizeof path);
+#ifdef _WIN32
+	if (strncmp(&path[1], ":\\", 2) == 0)
+		p = &path[3];
+	else
+#endif
+		p = path;
+	for (; start > 0; --start)
+	{
+		p += strspn(p, PATHSEP);
+		if (!( p = strchr(p, PATHSEP[0]) ))
+			return;
+	}
+	p += strspn(p, PATHSEP);
+	for (;;)
+	{
+		t = p;
+		if (( p = strchr(p, PATHSEP[0]) ))
+		{
+			*p = '\0';
+			I_mkdir(path, mode);
+			*p = PATHSEP[0];
+			p += strspn(p, PATHSEP);
+		}
+		else
+		{
+			if (*t)
+				I_mkdir(path, mode);
+			break;
+		}
+	}
+}

src/m_misc.h

@@ -96,6 +96,10 @@ void M_SetupMemcpy(void);
 
 const char *M_FileError(FILE *handle);
 
+int     M_PathParts      (const char *path);
+boolean M_IsPathAbsolute (const char *path);
+void    M_MkdirEach      (const char *path, int start, int mode);
+
 // counting bits, for weapon ammo code, usually
 FUNCMATH UINT8 M_CountBits(UINT32 num, UINT8 size);
 

src/sdl/i_main.c

@@ -20,6 +20,7 @@
 #include "../doomdef.h"
 #include "../m_argv.h"
 #include "../d_main.h"
+#include "../m_misc.h"/* path shit */
 #include "../i_system.h"
 
 #ifdef __GNUC__
@@ -134,6 +135,8 @@ int main(int argc, char **argv)
 		time_t my_time;
 		struct tm * timeinfo;
 		const char *format;
+		const char *reldir;
+		int left;
 
 		logdir = D_Home();
 
@@ -145,24 +148,37 @@ int main(int argc, char **argv)
 		else
 			format = "log-%Y-%m-%d_%H-%M-%S.txt";
 
-		strftime(logfile, sizeof logfile, format, timeinfo);
+		if (M_CheckParm("-logdir") && M_IsNextParm())
+			reldir = M_GetNextParm();
+		else
+			reldir = "logs";
 
+		if (M_IsPathAbsolute(reldir))
+		{
+			left = snprintf(logfile, sizeof logfile,
+					"%s"PATHSEP, reldir);
+		}
+		else
 #ifdef DEFAULTDIR
 		if (logdir)
 		{
-			// Create dirs here because D_SRB2Main() is too late.
-			I_mkdir(va("%s%s"DEFAULTDIR, logdir, PATHSEP), 0755);
-			I_mkdir(va("%s%s"DEFAULTDIR"%slogs",logdir, PATHSEP, PATHSEP), 0755);
-			logstream = fopen(va("%s%s"DEFAULTDIR"%slogs%s%s",logdir, PATHSEP, PATHSEP, PATHSEP, logfile), "wt");
+			left = snprintf(logfile, sizeof logfile,
+					"%s"PATHSEP DEFAULTDIR PATHSEP"%s"PATHSEP, logdir, reldir);
 		}
 		else
-#endif
+#endif/*DEFAULTDIR*/
 		{
-			I_mkdir("."PATHSEP"logs"PATHSEP, 0755);
-			logstream = fopen(va("."PATHSEP"logs"PATHSEP"%s", logfile), "wt");
+			left = snprintf(logfile, sizeof logfile,
+					"."PATHSEP"%s"PATHSEP, reldir);
 		}
+#endif/*LOGMESSAGES*/
+
+		M_MkdirEach(logfile, M_PathParts(logdir) - 1, 0755);
+
+		strftime(&logfile[left], sizeof logfile - left, format, timeinfo);
+
+		logstream = fopen(logfile, "wt");
 	}
-#endif
 
 	//I_OutputMsg("I_StartupSystem() ...\n");
 	I_StartupSystem();