vis: also lookup Lua support files relative to the binary location

This simplifies deployment of vis on remote systems without root
access. The idea is to extract a statically linked binary together with
the lexer syntax files into some directory, adjust $PATH to include it
and have everything just work.

For now this uses /proc/self/exe and thus only works on Linux based
systems.

5 files changed, 23 insertions, 5 deletions

diff --git a/GNUmakefile b/GNUmakefile
index f6e57d7..4773324 100644
--- a/GNUmakefile
+++ b/GNUmakefile
@@ -147,7 +147,7 @@ local: clean dependencies
 		CFLAGS_TERMKEY=	LDFLAGS_TERMKEY=-ltermkey \
 		CFLAGS_LUA="-DLUA_COMPAT_5_1 -DLUA_COMPAT_5_2 -DLUA_COMPAT_ALL" \
 		LDFLAGS_LUA="-llua -lm -ldl"
-	@echo Run with: LD_LIBRARY_PATH=$(DEPS_LIB) VIS_PATH=. ./vis
+	@echo Run with: LD_LIBRARY_PATH=$(DEPS_LIB) ./vis
 
 standalone: clean dependency/sources/install-libmusl
 	PATH=$(DEPS_BIN):$$PATH PKG_CONFIG_PATH= PKG_CONFIG_LIBDIR= $(MAKE) \
@@ -160,6 +160,5 @@ standalone: clean dependency/sources/install-libmusl
 		LDFLAGS_LUA="-llua -lm -ldl" \
 		CONFIG_ACL=0 CFLAGS_ACL= LDFLAGS_ACL= \
 		CONFIG_SELINUX=0 CFLAGS_SELINUX= LDFLAGS_SELINUX=
-	@echo Run with: VIS_PATH=. ./vis
 
 .PHONY: standalone dependencies dependencies-full local
\ No newline at end of file
diff --git a/README.md b/README.md
index 367d020..9fb3e00 100644
--- a/README.md
+++ b/README.md
@@ -47,8 +47,7 @@ In order to build vis you will need a C99 compiler as well as:
 
 Assuming these dependencies are met, execute:
 
-    $ ./configure && make
-    $ VIS_PATH=. ./vis config.h
+    $ ./configure && make && sudo make install
 
 By default the `configure` script will try to auto detect support for
 Lua. See `configure --help` for a list of supported options. You can
diff --git a/lexers/README.md b/lexers/README.md
index a7d25c2..34ca587 100644
--- a/lexers/README.md
+++ b/lexers/README.md
@@ -9,6 +9,7 @@ based lexers from the [Scintillua](http://foicica.com/scintillua/) project.
 Vis searches the lexers in the following locations:
 
  * `$VIS_PATH/lexers`
+ * `./lexers` relative to the binary location (using `/proc/self/exe`)
  * `$XDG_CONFIG_HOME/vis/lexers`
  * `/usr/local/share/vis/lexers`
  * `/usr/share/vis/lexers`
diff --git a/vis-lua.c b/vis-lua.c
index 35dbe95..c25f64d 100644
--- a/vis-lua.c
+++ b/vis-lua.c
@@ -1,6 +1,9 @@
 #include <stdarg.h>
 #include <stdio.h>
 #include <string.h>
+#include <limits.h>
+#include <unistd.h>
+#include <libgen.h>
 #include <sys/types.h>
 #include <pwd.h>
 
@@ -823,6 +826,7 @@ void vis_lua_start(Vis *vis) {
 
 	/* extends lua's package.path with:
 	 * - $VIS_PATH/{,lexers}
+	 * - {,lexers} relative to the binary location
 	 * - $XDG_CONFIG_HOME/vis/{,lexers} (defaulting to $HOME/.config/vis/{,lexers})
 	 * - /usr/local/share/vis/{,lexers}
 	 * - /usr/share/vis/{,lexers}
@@ -841,6 +845,19 @@ void vis_lua_start(Vis *vis) {
 		paths++;
 	}
 
+	char exe[PATH_MAX];
+	ssize_t len = readlink("/proc/self/exe", exe, sizeof(exe)-1);
+	if (len > 0) {
+		exe[len] = '\0';
+		char *exe_path = dirname(exe);
+		lua_pushstring(L, exe_path);
+		lua_pushstring(L, "/?.lua;");
+		lua_pushstring(L, exe_path);
+		lua_pushstring(L, "/lexers/?.lua;");
+		lua_concat(L, 4);
+		paths++;
+	}
+
 	/* try to get users home directory */
 	const char *home = getenv("HOME");
 	if (!home || !*home) {
diff --git a/vis.1 b/vis.1
index 4aafd4e..b655921 100644
--- a/vis.1
+++ b/vis.1
@@ -24,7 +24,9 @@ Defaults (in this order) to:
 .RS
 .RS
 .TP
-.B  $XDG_CONFIG_HOME/vis
+The location of the vis binary
+.TP
+.B $XDG_CONFIG_HOME/vis
 where
 .B $XDG_CONFIG_HOME
 refers to