From: Junio C Hamano <junkio@cox.net>
Date: Wed, 11 Jan 2006 00:42:44 GMT
Subject: Re: [PATCH 2/2] Remember and use GIT_EXEC_PATH on exec()'s
Message-ID: <7vd5iz4mt7.fsf@assigned-by-dhcp.cox.net>
In-Reply-To: <1136924980.11717.603.camel@brick.watson.ibm.com>

Michal Ostrowski <mostrows@watson.ibm.com> writes:

> How about searching for executables in the following places, and in this
> order:
>
> 1. --exec-path setting, if any
> 2. GIT_EXEC_PATH env var, if set
> 3. PATH (never modified)
> 4. Value of ${bindir} at build time

My preference is to first do this to the Makefile:

-- >8 --
diff --git a/Makefile b/Makefile
index 5817e86..b1e3055 100644
--- a/Makefile
+++ b/Makefile
@@ -71,6 +71,7 @@ ALL_LDFLAGS = $(LDFLAGS)
 
 prefix = $(HOME)
 bindir = $(prefix)/bin
+gitexecdir = $(prefix)/bin
 template_dir = $(prefix)/share/git-core/templates/
 GIT_PYTHON_DIR = $(prefix)/share/git-core/python
 # DESTDIR=
@@ -144,7 +145,7 @@ PROGRAMS = \
 	git-describe$X
 
 # what 'all' will build and 'install' will install.
-ALL_PROGRAMS = $(PROGRAMS) $(SIMPLE_PROGRAMS) $(SCRIPTS) git$X
+ALL_PROGRAMS = $(PROGRAMS) $(SIMPLE_PROGRAMS) $(SCRIPTS)
 
 # Backward compatibility -- to be removed after 1.0
 PROGRAMS += git-ssh-pull$X git-ssh-push$X
@@ -368,13 +369,13 @@ LIB_OBJS += $(COMPAT_OBJS)
 export prefix TAR INSTALL DESTDIR SHELL_PATH template_dir
 ### Build rules
 
-all: $(ALL_PROGRAMS)
+all: $(ALL_PROGRAMS) git$X
 
 all:
 	$(MAKE) -C templates
 
 git$X: git.c $(LIB_FILE)
-	$(CC) -DGIT_EXEC_PATH='"$(bindir)"' -DGIT_VERSION='"$(GIT_VERSION)"' \
+	$(CC) -DGIT_EXEC_PATH='"$(gitexecdir)"' -DGIT_VERSION='"$(GIT_VERSION)"' \
 		$(CFLAGS) $(COMPAT_CFLAGS) -o $@ $(filter %.c,$^) $(LIB_FILE)
 
 $(patsubst %.sh,%,$(SCRIPT_SH)) : % : %.sh
@@ -470,7 +471,9 @@ check:
 
 install: all
 	$(INSTALL) -d -m755 $(call shellquote,$(DESTDIR)$(bindir))
-	$(INSTALL) $(ALL_PROGRAMS) $(call shellquote,$(DESTDIR)$(bindir))
+	$(INSTALL) -d -m755 $(call shellquote,$(DESTDIR)$(gitexecdir))
+	$(INSTALL) $(ALL_PROGRAMS) $(call shellquote,$(DESTDIR)$(gitexecdir))
+	$(INSTALL) git$X $(call shellquote,$(DESTDIR)$(bindir))
 	$(MAKE) -C templates install
 	$(INSTALL) -d -m755 $(call shellquote,$(DESTDIR)$(GIT_PYTHON_DIR))
 	$(INSTALL) $(PYMODULES) $(call shellquote,$(DESTDIR)$(GIT_PYTHON_DIR))

-- 8< --

and then make the rule for git things:

 1. --exec-path
 2. GIT_EXEC_PATH environment
 3. $(gitexecdir)

in this order.  Non git things should just use $PATH without
looking at anything else --- as long as a hook script calls a git
wrapper (i.e. "git foo" not "git-foo") I think things should
work fine.

> ...  The patch I sent out this morning
> attempts to do this.  (I'll append again to avoid confusion with
> previous patches)...

> +		if (flags & RUN_GIT_CMD) {
> +			execv_git_cmd(argv);
> +		} else {
> +			execvp(argv[0], (char *const*) argv);
>  		}

This bit sounds good, but if you were to go this route I'd
suggest to rename your exec_git_cmd() to execl_git_cmd() (and
terminate the vararg list with NULL) for naming consistency.
execv_git_cmd() is good---we do not *want* execvp_git_cmd(),
because we do not run git subcommand using PATH.