fvwmorg · ThomasAdam · Jun 7, 2020 · Jun 7, 2020
diff --git a/doc/fvwm/environment.xml b/doc/fvwm/environment.xml
@@ -20,6 +20,14 @@ are the following:
 	option is given.</para>
     </listitem>
   </varlistentry>
+  <varlistentry>
+    <term><envar>FVWM3_LOGFILE</envar></term>
+    <listitem>
+      <para>Used to determine the path and filename to log debug information
+	      from fvwm3.
+      </para>
+    </listitem>
+  </varlistentry>
   <varlistentry>
     <term><envar>FVWM_MODULEDIR</envar></term>
     <listitem>

diff --git a/fvwm/fvwm3.c b/fvwm/fvwm3.c
@@ -24,9 +24,6 @@
 #ifdef HAVE_FCNTL_H
 #include <fcntl.h>
 #endif
-#ifdef HAVE_GETPWUID
-#  include <pwd.h>
-#endif
 #if HAVE_SYS_SYSTEMINFO_H
 /* Solaris has sysinfo instead of gethostname.  */
 #include <sys/systeminfo.h>
@@ -49,6 +46,7 @@
 #include "libs/FRenderInit.h"
 #include "libs/charmap.h"
 #include "libs/wcontext.h"
+#include "libs/getpwuid.h"
 #include "fvwm.h"
 #include "externs.h"
 #include "cursor.h"
@@ -122,7 +120,7 @@ static char l_g_bits[] =
 static char s_g_bits[] =
 {0x01, 0x02, 0x04, 0x08};
 
-static char *home_dir;
+static const char *home_dir;
 
 static volatile sig_atomic_t fvwmRunState = FVWM_RUNNING;
 
@@ -1790,17 +1788,7 @@ int main(int argc, char **argv)
 	flib_putenv("FVWM_MODULEDIR", "FVWM_MODULEDIR=" FVWM_MODULEDIR);
 
 	/* Figure out user's home directory */
-	home_dir = getenv("HOME");
-#ifdef HAVE_GETPWUID
-	if (home_dir == NULL)
-	{
-		struct passwd* pw = getpwuid(getuid());
-		if (pw != NULL)
-		{
-			home_dir = fxstrdup(pw->pw_dir);
-		}
-	}
-#endif
+	home_dir = find_home_dir();
 	if (home_dir == NULL)
 	{
 		home_dir = "/"; /* give up and use root dir */

diff --git a/libs/Makefile.am b/libs/Makefile.am
@@ -14,8 +14,8 @@ libfvwm3_a_SOURCES = \
 	PictureUtils.h Rectangles.h Strings.h System.h Target.h WinMagic.h \
 	XError.h XResource.h charmap.h defaults.h envvar.h fio.h flist.h fqueue.h \
 	fsm.h ftime.h fvwm_sys_stat.h fvwmlib.h fvwmrect.h fvwmsignal.h \
-	gravity.c gravity.h lang-strings.h log.h modifiers.h queue.h safemalloc.h \
-	setpgrp.h strlcpy.h timeout.h vpacket.h wcontext.h wild.h \
+	gravity.c gravity.h getpwuid.h lang-strings.h log.h modifiers.h queue.h \
+	safemalloc.h setpgrp.h strlcpy.h timeout.h vpacket.h wcontext.h wild.h \
 	\
 	BidiJoin.c Flocale.c PictureUtils.c FScreen.c Graphics.c \
 	PictureGraphics.c Bindings.c FlocaleCharset.c Parse.c \
@@ -26,7 +26,7 @@ libfvwm3_a_SOURCES = \
 	fvwmrect.c FRenderInit.c safemalloc.c  FBidi.c \
 	wild.c Grab.c Event.c ClientMsg.c setpgrp.c FShape.c \
 	FGettext.c Rectangles.c timeout.c flist.c charmap.c wcontext.c \
-	modifiers.c fsm.c FTips.c fio.c fvwmlib3.c strlcpy.c
+	modifiers.c fsm.c FTips.c fio.c fvwmlib3.c strlcpy.c getpwuid.c
 
 libfvwm3_a_LIBADD = @LIBOBJS@
 

diff --git a/libs/getpwuid.c b/libs/getpwuid.c
@@ -0,0 +1,74 @@
+/* This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see: <http://www.gnu.org/licenses/>
+ */
+
+#include "config.h"
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "safemalloc.h"
+#include "getpwuid.h"
+
+const char
+*find_home_dir(void)
+{
+	struct passwd		*pw;
+	const char		*home;
+
+	home = getenv("HOME");
+	if (home == NULL || *home == '\0') {
+		pw = getpwuid(getuid());
+		if (pw != NULL)
+			home = pw->pw_dir;
+		else
+			home = NULL;
+	}
+
+	return (home);
+}
+
+const char *
+expand_path(const char *path)
+{
+	char			*expanded, *name;
+	const char		*end, *value, *home;
+
+	home = find_home_dir();
+
+	if (strncmp(path, "~/", 2) == 0) {
+		if (home == NULL)
+			return (NULL);
+		xasprintf(&expanded, "%s%s", home, path + 1);
+		return (expanded);
+	}
+
+	if (*path == '$') {
+		end = strchr(path, '/');
+		if (end == NULL)
+			name = fxstrdup(path + 1);
+		else
+			name = strndup(path + 1, end - path - 1);
+		value = getenv(name);
+		free(name);
+		if (value == NULL)
+			return (NULL);
+		if (end == NULL)
+			end = "";
+		xasprintf(&expanded, "%s%s", value, end);
+		return (expanded);
+	}
+
+	return (fxstrdup(path));
+}
diff --git a/libs/getpwuid.h b/libs/getpwuid.h
@@ -0,0 +1,25 @@
+/* This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see: <http://www.gnu.org/licenses/>
+ */
+
+#ifndef FVWM_GETPWUID_H
+#define FVWM_GETPWUID_H
+
+#ifdef HAVE_GETPWUID
+#  include <pwd.h>
+#endif
+
+const char	*find_home_dir(void);
+const char	*expand_path(const char *);
+
+#endif
diff --git a/libs/log.c b/libs/log.c
@@ -28,6 +28,7 @@
 #include <unistd.h>
 
 #include "fvwmlib.h"
+#include "getpwuid.h"
 #include "log.h"
 
 static FILE	*log_file;
@@ -46,17 +47,32 @@ log_set_level(int ll)
 void
 log_open(void)
 {
-	char	*path = "fvwm3-output.log";
+	char		*path = fxstrdup(FVWM3_LOGFILE_DEFAULT);
+
+	if (getenv("FVWM3_LOGFILE")) {
+		const char	*expanded_path;
+
+		free(path);
+		path = getenv("FVWM3_LOGFILE");
+		expanded_path = expand_path(path);
+
+		path = fxstrdup(expanded_path);
+		free((char *)expanded_path);
+	}
 
 	if (log_level == 0)
 		return;
 	log_close();
 
 	log_file = fopen(path, "a");
-	if (log_file == NULL)
+	if (log_file == NULL) {
+		free(path);
 		return;
+	}
 
 	setvbuf(log_file, NULL, _IOLBF, 0);
+
+	free(path);
 }
 
 /* Toggle logging. */

diff --git a/libs/log.h b/libs/log.h
@@ -2,6 +2,7 @@
 #define _LOG_H
 
 #define printflike(a, b) __attribute__ ((format (printf, a, b)))
+#define FVWM3_LOGFILE_DEFAULT "fvwm3-output.log"
 
 void	log_set_level(int);
 int	log_get_level(void);