Merge branch 'dj/runtime-prefix'

This topic branch first reverts a couple of conflicting patches and then
cherry-picks Dan Jacques' patches to support RUNTIME_PREFIX also on
other platforms than Windows. The original patches are already well
under way into the next Git version, and we just take them early to give
it a bit more testing.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>

.gitignore

@@ -3,6 +3,7 @@
 /GIT-LDFLAGS
 /GIT-PREFIX
 /GIT-PERL-DEFINES
+/GIT-PERL-HEADER
 /GIT-PYTHON-VARS
 /GIT-SCRIPT-DEFINES
 /GIT-USER-AGENT

Makefile

@@ -434,6 +434,29 @@ all::
 #
 # When cross-compiling, define HOST_CPU as the canonical name of the CPU on
 # which the built Git will run (for instance "x86_64").
+#
+# Define RUNTIME_PREFIX to configure Git to resolve its ancillary tooling and
+# support files relative to the location of the runtime binary, rather than
+# hard-coding them into the binary. Git installations built with RUNTIME_PREFIX
+# can be moved to arbitrary filesystem locations. RUNTIME_PREFIX also causes
+# Perl scripts to use a modified entry point header allowing them to resolve
+# support files at runtime.
+#
+# When using RUNTIME_PREFIX, define HAVE_BSD_KERN_PROC_SYSCTL if your platform
+# supports the KERN_PROC BSD sysctl function.
+#
+# When using RUNTIME_PREFIX, define PROCFS_EXECUTABLE_PATH if your platform
+# mounts a "procfs" filesystem capable of resolving the path of the current
+# executable. If defined, this must be the canonical path for the "procfs"
+# current executable path.
+#
+# When using RUNTIME_PREFIX, define HAVE_NS_GET_EXECUTABLE_PATH if your platform
+# supports calling _NSGetExecutablePath to retrieve the path of the running
+# executable.
+#
+# When using RUNTIME_PREFIX, define HAVE_WPGMPTR if your platform offers
+# the global variable _wpgmptr containing the absolute path of the current
+# executable (this is the case on Windows).
 
 GIT-VERSION-FILE: FORCE
 	@$(SHELL_PATH) ./GIT-VERSION-GEN
@@ -471,6 +494,8 @@ ARFLAGS = rcs
 #   mandir
 #   infodir
 #   htmldir
+#   localedir
+#   perllibdir
 # This can help installing the suite in a relocatable way.
 
 prefix = $(HOME)
@@ -494,7 +519,10 @@ pathsep = :
 
 mandir_relative = $(patsubst $(prefix)/%,%,$(mandir))
 infodir_relative = $(patsubst $(prefix)/%,%,$(infodir))
+gitexecdir_relative = $(patsubst $(prefix)/%,%,$(gitexecdir))
+localedir_relative = $(patsubst $(prefix)/%,%,$(localedir))
 htmldir_relative = $(patsubst $(prefix)/%,%,$(htmldir))
+perllibdir_relative = $(patsubst $(prefix)/%,%,$(perllibdir))
 
 export prefix bindir sharedir sysconfdir gitwebdir perllibdir localedir
 
@@ -1653,10 +1681,27 @@ ifdef HAVE_BSD_SYSCTL
 	BASIC_CFLAGS += -DHAVE_BSD_SYSCTL
 endif
 
+ifdef HAVE_BSD_KERN_PROC_SYSCTL
+	BASIC_CFLAGS += -DHAVE_BSD_KERN_PROC_SYSCTL
+endif
+
 ifdef HAVE_GETDELIM
 	BASIC_CFLAGS += -DHAVE_GETDELIM
 endif
 
+ifneq ($(PROCFS_EXECUTABLE_PATH),)
+	procfs_executable_path_SQ = $(subst ','\'',$(PROCFS_EXECUTABLE_PATH))
+	BASIC_CFLAGS += '-DPROCFS_EXECUTABLE_PATH="$(procfs_executable_path_SQ)"'
+endif
+
+ifdef HAVE_NS_GET_EXECUTABLE_PATH
+	BASIC_CFLAGS += -DHAVE_NS_GET_EXECUTABLE_PATH
+endif
+
+ifdef HAVE_WPGMPTR
+	BASIC_CFLAGS += -DHAVE_WPGMPTR
+endif
+
 ifeq ($(TCLTK_PATH),)
 NO_TCLTK = NoThanks
 endif
@@ -1741,10 +1786,12 @@ mandir_relative_SQ = $(subst ','\'',$(mandir_relative))
 infodir_relative_SQ = $(subst ','\'',$(infodir_relative))
 perllibdir_SQ = $(subst ','\'',$(perllibdir))
 localedir_SQ = $(subst ','\'',$(localedir))
+localedir_relative_SQ = $(subst ','\'',$(localedir_relative))
 gitexecdir_SQ = $(subst ','\'',$(gitexecdir))
 template_dir_SQ = $(subst ','\'',$(template_dir))
 htmldir_relative_SQ = $(subst ','\'',$(htmldir_relative))
 prefix_SQ = $(subst ','\'',$(prefix))
+perllibdir_relative_SQ = $(subst ','\'',$(perllibdir_relative))
 gitwebdir_SQ = $(subst ','\'',$(gitwebdir))
 
 SHELL_PATH_SQ = $(subst ','\'',$(SHELL_PATH))
@@ -1755,6 +1802,31 @@ TCLTK_PATH_SQ = $(subst ','\'',$(TCLTK_PATH))
 DIFF_SQ = $(subst ','\'',$(DIFF))
 PERLLIB_EXTRA_SQ = $(subst ','\'',$(PERLLIB_EXTRA))
 
+# RUNTIME_PREFIX's resolution logic requires resource paths to be expressed
+# relative to each other and share an installation path.
+#
+# This is a dependency in:
+# - Git's binary RUNTIME_PREFIX logic in (see "exec_cmd.c").
+# - The runtime prefix Perl header (see
+#   "perl/header_templates/runtime_prefix.template.pl").
+ifdef RUNTIME_PREFIX
+
+ifneq ($(filter /%,$(firstword $(gitexecdir_relative))),)
+$(error RUNTIME_PREFIX requires a relative gitexecdir, not: $(gitexecdir))
+endif
+
+ifneq ($(filter /%,$(firstword $(localedir_relative))),)
+$(error RUNTIME_PREFIX requires a relative localedir, not: $(localedir))
+endif
+
+ifndef NO_PERL
+ifneq ($(filter /%,$(firstword $(perllibdir_relative))),)
+$(error RUNTIME_PREFIX requires a relative perllibdir, not: $(perllibdir))
+endif
+endif
+
+endif
+
 # We must filter out any object files from $(GITLIBS),
 # as it is typically used like:
 #
@@ -1975,27 +2047,44 @@ git.res: git.rc GIT-VERSION-FILE GIT-PREFIX
 # This makes sure we depend on the NO_PERL setting itself.
 $(SCRIPT_PERL_GEN): GIT-BUILD-OPTIONS
 
-ifndef NO_PERL
-$(SCRIPT_PERL_GEN):
+# Used for substitution in Perl modules. Disabled when using RUNTIME_PREFIX
+# since the locale directory is injected.
+perl_localedir_SQ = $(localedir_SQ)
 
+ifndef NO_PERL
+PERL_HEADER_TEMPLATE = perl/header_templates/fixed_prefix.template.pl
 PERL_DEFINES = $(PERL_PATH_SQ):$(PERLLIB_EXTRA_SQ):$(perllibdir_SQ)
-$(SCRIPT_PERL_GEN): % : %.perl GIT-PERL-DEFINES GIT-VERSION-FILE
+
+PERL_DEFINES := $(PERL_PATH_SQ) $(PERLLIB_EXTRA_SQ) $(perllibdir_SQ)
+PERL_DEFINES += $(RUNTIME_PREFIX)
+
+# Support Perl runtime prefix. In this mode, a different header is installed
+# into Perl scripts.
+ifdef RUNTIME_PREFIX
+
+PERL_HEADER_TEMPLATE = perl/header_templates/runtime_prefix.template.pl
+
+# Don't export a fixed $(localedir) path; it will be resolved by the Perl header
+# at runtime.
+perl_localedir_SQ =
+
+endif
+
+PERL_DEFINES += $(gitexecdir) $(perllibdir) $(localedir)
+
+$(SCRIPT_PERL_GEN): % : %.perl GIT-PERL-DEFINES GIT-PERL-HEADER GIT-VERSION-FILE
 	$(QUIET_GEN)$(RM) $@ $@+ && \
-	INSTLIBDIR='$(perllibdir_SQ)' && \
-	INSTLIBDIR_EXTRA='$(PERLLIB_EXTRA_SQ)' && \
-	INSTLIBDIR="$$INSTLIBDIR$${INSTLIBDIR_EXTRA:+:$$INSTLIBDIR_EXTRA}" && \
 	sed -e '1{' \
 	    -e '	s|#!.*perl|#!$(PERL_PATH_SQ)|' \
-	    -e '	h' \
-	    -e '	s=.*=use lib (split(/$(pathsep)/, $$ENV{GITPERLLIB} || "'"$$INSTLIBDIR"'"));=' \
-	    -e '	H' \
-	    -e '	x' \
+	    -e '	rGIT-PERL-HEADER' \
+	    -e '	G' \
 	    -e '}' \
 	    -e 's/@@GIT_VERSION@@/$(GIT_VERSION)/g' \
 	    $< >$@+ && \
 	chmod +x $@+ && \
 	mv $@+ $@
 
+PERL_DEFINES := $(subst $(space),:,$(PERL_DEFINES))
 GIT-PERL-DEFINES: FORCE
 	@FLAGS='$(PERL_DEFINES)'; \
 	    if test x"$$FLAGS" != x"`cat $@ 2>/dev/null`" ; then \
@@ -2003,6 +2092,19 @@ GIT-PERL-DEFINES: FORCE
 		echo "$$FLAGS" >$@; \
 	    fi
 
+GIT-PERL-HEADER: $(PERL_HEADER_TEMPLATE) GIT-PERL-DEFINES Makefile
+	$(QUIET_GEN)$(RM) $@ && \
+	INSTLIBDIR='$(perllibdir_SQ)' && \
+	INSTLIBDIR_EXTRA='$(PERLLIB_EXTRA_SQ)' && \
+	INSTLIBDIR="$$INSTLIBDIR$${INSTLIBDIR_EXTRA:+:$$INSTLIBDIR_EXTRA}" && \
+	sed -e 's=@@PATHSEP@@=$(pathsep)=g' \
+	    -e 's=@@INSTLIBDIR@@='$$INSTLIBDIR'=g' \
+	    -e 's=@@PERLLIBDIR@@='$(perllibdir_SQ)'=g' \
+	    -e 's=@@PERLLIBDIR_REL@@=$(perllibdir_relative_SQ)=g' \
+	    -e 's=@@GITEXECDIR_REL@@=$(gitexecdir_relative_SQ)=g' \
+	    -e 's=@@LOCALEDIR_REL@@=$(localedir_relative_SQ)=g' \
+	    $< >$@+ && \
+	mv $@+ $@
 
 .PHONY: gitweb
 gitweb:
@@ -2147,6 +2249,7 @@ endif
 exec_cmd.sp exec_cmd.s exec_cmd.o: GIT-PREFIX
 exec_cmd.sp exec_cmd.s exec_cmd.o: EXTRA_CPPFLAGS = \
 	'-DGIT_EXEC_PATH="$(gitexecdir_SQ)"' \
+	'-DGIT_LOCALE_PATH="$(localedir_relative_SQ)"' \
 	'-DBINDIR="$(bindir_relative_SQ)"' \
 	'-DFALLBACK_RUNTIME_PREFIX="$(prefix_SQ)"'
 
@@ -2164,7 +2267,7 @@ attr.sp attr.s attr.o: EXTRA_CPPFLAGS = \
 
 gettext.sp gettext.s gettext.o: GIT-PREFIX
 gettext.sp gettext.s gettext.o: EXTRA_CPPFLAGS = \
-	-DGIT_LOCALE_PATH='"$(localedir_SQ)"'
+	-DGIT_LOCALE_PATH='"$(localedir_relative_SQ)"'
 
 http-push.sp http.sp http-walker.sp remote-curl.sp imap-send.sp: SPARSE_FLAGS += \
 	-DCURL_DISABLE_TYPECHECK
@@ -2324,7 +2427,7 @@ endif
 
 perl/build/lib/%.pm: perl/%.pm
 	$(QUIET_GEN)mkdir -p $(dir $@) && \
-	sed -e 's|@@LOCALEDIR@@|$(localedir_SQ)|g' \
+	sed -e 's|@@LOCALEDIR@@|$(perl_localedir_SQ)|g' \
 	    -e 's|@@NO_PERL_CPAN_FALLBACKS@@|$(NO_PERL_CPAN_FALLBACKS_SQ)|g' \
 	< $< > $@
 
@@ -2799,7 +2902,7 @@ ifndef NO_TCLTK
 endif
 	$(RM) GIT-VERSION-FILE GIT-CFLAGS GIT-LDFLAGS GIT-BUILD-OPTIONS
 	$(RM) GIT-USER-AGENT GIT-PREFIX
-	$(RM) GIT-SCRIPT-DEFINES GIT-PERL-DEFINES GIT-PYTHON-VARS
+	$(RM) GIT-SCRIPT-DEFINES GIT-PERL-DEFINES GIT-PERL-HEADER GIT-PYTHON-VARS
 ifdef MSVC
 	$(RM) $(patsubst %.o,%.o.pdb,$(OBJECTS))
 	$(RM) $(patsubst %.exe,%.pdb,$(OTHER_PROGRAMS))

cache.h

@@ -428,6 +428,7 @@ static inline enum object_type object_type(unsigned int mode)
 #define GIT_ICASE_PATHSPECS_ENVIRONMENT "GIT_ICASE_PATHSPECS"
 #define GIT_QUARANTINE_ENVIRONMENT "GIT_QUARANTINE_PATH"
 #define GIT_OPTIONAL_LOCKS_ENVIRONMENT "GIT_OPTIONAL_LOCKS"
+#define GIT_TEXT_DOMAIN_DIR_ENVIRONMENT "GIT_TEXTDOMAINDIR"
 
 /*
  * Environment variable used in handshaking the wire protocol.

common-main.c

@@ -32,12 +32,12 @@ int main(int argc, const char **argv)
 	 */
 	sanitize_stdfds();
 
+	git_resolve_executable_dir(argv[0]);
+
 	git_setup_gettext();
 
 	attr_start();
 
-	git_extract_argv0_path(argv[0]);
-
 	restore_sigpipe_to_default();
 
 	return cmd_main(argc, argv);

compat/mingw.c

@@ -3453,7 +3453,7 @@ void mingw_startup(void)
 		die_startup();
 
 	/* determine size of argv and environ conversion buffer */
-	maxlen = wcslen(_wpgmptr);
+	maxlen = wcslen(wargv[0]);
 	for (i = 1; i < argc; i++)
 		maxlen = max(maxlen, wcslen(wargv[i]));
 	for (i = 0; wenv[i]; i++)
@@ -3473,8 +3473,7 @@ void mingw_startup(void)
 	buffer = malloc_startup(maxlen);
 
 	/* convert command line arguments and environment to UTF-8 */
-	__argv[0] = wcstoutfdup_startup(buffer, _wpgmptr, maxlen);
-	for (i = 1; i < argc; i++)
+	for (i = 0; i < argc; i++)
 		__argv[i] = wcstoutfdup_startup(buffer, wargv[i], maxlen);
 	for (i = 0; wenv[i]; i++)
 		environ[i] = wcstoutfdup_startup(buffer, wenv[i], maxlen);

config.mak.uname

@@ -56,6 +56,7 @@ ifeq ($(uname_S),Linux)
 	HAVE_GETDELIM = YesPlease
 	SANE_TEXT_GREP=-a
 	FREAD_READS_DIRECTORIES = UnfortunatelyYes
+	PROCFS_EXECUTABLE_PATH = /proc/self/exe
 endif
 ifeq ($(uname_S),GNU/kFreeBSD)
 	HAVE_ALLOCA_H = YesPlease
@@ -130,6 +131,7 @@ ifeq ($(uname_S),Darwin)
 	BASIC_CFLAGS += -DPROTECT_HFS_DEFAULT=1
 	HAVE_BSD_SYSCTL = YesPlease
 	FREAD_READS_DIRECTORIES = UnfortunatelyYes
+	HAVE_NS_GET_EXECUTABLE_PATH = YesPlease
 endif
 ifeq ($(uname_S),SunOS)
 	NEEDS_SOCKET = YesPlease
@@ -224,6 +226,7 @@ ifeq ($(uname_S),FreeBSD)
 	HAVE_PATHS_H = YesPlease
 	GMTIME_UNRELIABLE_ERRORS = UnfortunatelyYes
 	HAVE_BSD_SYSCTL = YesPlease
+	HAVE_BSD_KERN_PROC_SYSCTL = YesPlease
 	PAGER_ENV = LESS=FRX LV=-c MORE=FRX
 	FREAD_READS_DIRECTORIES = UnfortunatelyYes
 endif
@@ -236,6 +239,8 @@ ifeq ($(uname_S),OpenBSD)
 	BASIC_LDFLAGS += -L/usr/local/lib
 	HAVE_PATHS_H = YesPlease
 	HAVE_BSD_SYSCTL = YesPlease
+	HAVE_BSD_KERN_PROC_SYSCTL = YesPlease
+	PROCFS_EXECUTABLE_PATH = /proc/curproc/file
 endif
 ifeq ($(uname_S),MirBSD)
 	NO_STRCASESTR = YesPlease
@@ -254,6 +259,8 @@ ifeq ($(uname_S),NetBSD)
 	USE_ST_TIMESPEC = YesPlease
 	HAVE_PATHS_H = YesPlease
 	HAVE_BSD_SYSCTL = YesPlease
+	HAVE_BSD_KERN_PROC_SYSCTL = YesPlease
+	PROCFS_EXECUTABLE_PATH = /proc/curproc/exe
 endif
 ifeq ($(uname_S),AIX)
 	DEFAULT_PAGER = more
@@ -388,6 +395,7 @@ ifeq ($(uname_S),Windows)
 	# SNPRINTF_RETURNS_BOGUS = YesPlease
 	NO_SVN_TESTS = YesPlease
 	RUNTIME_PREFIX = YesPlease
+	HAVE_WPGMPTR = YesWeDo
 	NO_ST_BLOCKS_IN_STRUCT_STAT = YesPlease
 	USE_WIN32_MMAP = YesPlease
 	MMAP_PREVENTS_DELETE = UnfortunatelyYes
@@ -556,6 +564,7 @@ ifneq (,$(findstring MINGW,$(uname_S)))
 	NO_MKDTEMP = YesPlease
 	NO_SVN_TESTS = YesPlease
 	RUNTIME_PREFIX = YesPlease
+	HAVE_WPGMPTR = YesWeDo
 	NO_ST_BLOCKS_IN_STRUCT_STAT = YesPlease
 	USE_WIN32_MMAP = YesPlease
 	MMAP_PREVENTS_DELETE = UnfortunatelyYes

exec_cmd.c

@@ -2,24 +2,52 @@
 #include "exec_cmd.h"
 #include "quote.h"
 #include "argv-array.h"
-#define MAX_ARGS	32
 
-static const char *argv_exec_path;
+#if defined(RUNTIME_PREFIX)
+
+#if defined(HAVE_NS_GET_EXECUTABLE_PATH)
+#include <mach-o/dyld.h>
+#endif
+
+#if defined(HAVE_BSD_KERN_PROC_SYSCTL)
+#include <sys/param.h>
+#include <sys/types.h>
+#include <sys/sysctl.h>
+#endif
+
+#endif /* RUNTIME_PREFIX */
+
+#define MAX_ARGS 32
+
+static const char *system_prefix(void);
 
 #ifdef RUNTIME_PREFIX
-static const char *argv0_path;
+
+/**
+ * When using a runtime prefix, Git dynamically resolves paths relative to its
+ * executable.
+ *
+ * The method for determining the path of the executable is highly
+ * platform-specific.
+ */
+
+/**
+ * Path to the current Git executable. Resolved on startup by
+ * 'git_resolve_executable_dir'.
+ */
+static const char *executable_dirname;
 
 static const char *system_prefix(void)
 {
 	static const char *prefix;
 
-	assert(argv0_path);
-	assert(is_absolute_path(argv0_path));
+	assert(executable_dirname);
+	assert(is_absolute_path(executable_dirname));
 
 	if (!prefix &&
-	    !(prefix = strip_path_suffix(argv0_path, GIT_EXEC_PATH)) &&
-	    !(prefix = strip_path_suffix(argv0_path, BINDIR)) &&
-	    !(prefix = strip_path_suffix(argv0_path, "git"))) {
+	    !(prefix = strip_path_suffix(executable_dirname, GIT_EXEC_PATH)) &&
+	    !(prefix = strip_path_suffix(executable_dirname, BINDIR)) &&
+	    !(prefix = strip_path_suffix(executable_dirname, "git"))) {
 		prefix = FALLBACK_RUNTIME_PREFIX;
 		trace_printf("RUNTIME_PREFIX requested, "
 				"but prefix computation failed.  "
@@ -28,27 +56,201 @@ static const char *system_prefix(void)
 	return prefix;
 }
 
-void git_extract_argv0_path(const char *argv0)
+/*
+ * Resolves the executable path from argv[0], only if it is absolute.
+ *
+ * Returns 0 on success, -1 on failure.
+ */
+static int git_get_exec_path_from_argv0(struct strbuf *buf, const char *argv0)
 {
 	const char *slash;
 
 	if (!argv0 || !*argv0)
-		return;
+		return -1;
 
 	slash = find_last_dir_sep(argv0);
+	if (slash) {
+		trace_printf("trace: resolved executable path from argv0: %s\n",
+			     argv0);
+		strbuf_add_absolute_path(buf, argv0);
+		return 0;
+	}
+	return -1;
+}
 
+#ifdef PROCFS_EXECUTABLE_PATH
+/*
+ * Resolves the executable path by examining a procfs symlink.
+ *
+ * Returns 0 on success, -1 on failure.
+ */
+static int git_get_exec_path_procfs(struct strbuf *buf)
+{
+	if (strbuf_realpath(buf, PROCFS_EXECUTABLE_PATH, 0)) {
+		trace_printf(
+			"trace: resolved executable path from procfs: %s\n",
+			buf->buf);
+		return 0;
+	}
+	return -1;
+}
+#endif /* PROCFS_EXECUTABLE_PATH */
+
+#ifdef HAVE_BSD_KERN_PROC_SYSCTL
+/*
+ * Resolves the executable path using KERN_PROC_PATHNAME BSD sysctl.
+ *
+ * Returns 0 on success, -1 on failure.
+ */
+static int git_get_exec_path_bsd_sysctl(struct strbuf *buf)
+{
+	int mib[4];
+	char path[MAXPATHLEN];
+	size_t cb = sizeof(path);
+
+	mib[0] = CTL_KERN;
+	mib[1] = KERN_PROC;
+	mib[2] = KERN_PROC_PATHNAME;
+	mib[3] = -1;
+	if (!sysctl(mib, 4, path, &cb, NULL, 0)) {
+		trace_printf(
+			"trace: resolved executable path from sysctl: %s\n",
+			path);
+		strbuf_addstr(buf, path);
+		return 0;
+	}
+	return -1;
+}
+#endif /* HAVE_BSD_KERN_PROC_SYSCTL */
+
+#ifdef HAVE_NS_GET_EXECUTABLE_PATH
+/*
+ * Resolves the executable path by querying Darwin application stack.
+ *
+ * Returns 0 on success, -1 on failure.
+ */
+static int git_get_exec_path_darwin(struct strbuf *buf)
+{
+	char path[PATH_MAX];
+	uint32_t size = sizeof(path);
+	if (!_NSGetExecutablePath(path, &size)) {
+		trace_printf(
+			"trace: resolved executable path from Darwin stack: %s\n",
+			path);
+		strbuf_addstr(buf, path);
+		return 0;
+	}
+	return -1;
+}
+#endif /* HAVE_NS_GET_EXECUTABLE_PATH */
+
+#ifdef HAVE_WPGMPTR
+/*
+ * Resolves the executable path by using the global variable _wpgmptr.
+ *
+ * Returns 0 on success, -1 on failure.
+ */
+static int git_get_exec_path_wpgmptr(struct strbuf *buf)
+{
+	int len = wcslen(_wpgmptr) * 3 + 1;
+	strbuf_grow(buf, len);
+	len = xwcstoutf(buf->buf, _wpgmptr, len);
+	if (len < 0)
+		return -1;
+	buf->len += len;
+	return 0;
+}
+#endif /* HAVE_WPGMPTR */
+
+/*
+ * Resolves the absolute path of the current executable.
+ *
+ * Returns 0 on success, -1 on failure.
+ */
+static int git_get_exec_path(struct strbuf *buf, const char *argv0)
+{
+	/*
+	 * Identifying the executable path is operating system specific.
+	 * Selectively employ all available methods in order of preference,
+	 * preferring highly-available authoritative methods over
+	 * selectively-available or non-authoritative methods.
+	 *
+	 * All cases fall back on resolving against argv[0] if there isn't a
+	 * better functional method. However, note that argv[0] can be
+	 * used-supplied on many operating systems, and is not authoritative
+	 * in those cases.
+	 *
+	 * Each of these functions returns 0 on success, so evaluation will stop
+	 * after the first successful method.
+	 */
+	if (
+#ifdef HAVE_BSD_KERN_PROC_SYSCTL
+		git_get_exec_path_bsd_sysctl(buf) &&
+#endif /* HAVE_BSD_KERN_PROC_SYSCTL */
+
+#ifdef HAVE_NS_GET_EXECUTABLE_PATH
+		git_get_exec_path_darwin(buf) &&
+#endif /* HAVE_NS_GET_EXECUTABLE_PATH */
+
+#ifdef PROCFS_EXECUTABLE_PATH
+		git_get_exec_path_procfs(buf) &&
+#endif /* PROCFS_EXECUTABLE_PATH */
+
+#ifdef HAVE_WPGMPTR
+		git_get_exec_path_wpgmptr(buf) &&
+#endif /* HAVE_WPGMPTR */
+
+		git_get_exec_path_from_argv0(buf, argv0)) {
+		return -1;
+	}
+
+	if (strbuf_normalize_path(buf)) {
+		trace_printf("trace: could not normalize path: %s\n", buf->buf);
+		return -1;
+	}
+
+	return 0;
+}
+
+void git_resolve_executable_dir(const char *argv0)
+{
+	struct strbuf buf = STRBUF_INIT;
+	char *resolved;
+	const char *slash;
+
+	if (git_get_exec_path(&buf, argv0)) {
+		trace_printf(
+			"trace: could not determine executable path from: %s\n",
+			argv0);
+		strbuf_release(&buf);
+		return;
+	}
+
+	resolved = strbuf_detach(&buf, NULL);
+	slash = find_last_dir_sep(resolved);
 	if (slash)
-		argv0_path = xstrndup(argv0, slash - argv0);
+		resolved[slash - resolved] = '\0';
+
+	executable_dirname = resolved;
+	trace_printf("trace: resolved executable dir: %s\n",
+		     executable_dirname);
 }
 
 #else
 
+/*
+ * When not using a runtime prefix, Git uses a hard-coded path.
+ */
 static const char *system_prefix(void)
 {
 	return FALLBACK_RUNTIME_PREFIX;
 }
 
-void git_extract_argv0_path(const char *argv0)
+/*
+ * This is called during initialization, but No work needs to be done here when
+ * runtime prefix is not being used.
+ */
+void git_resolve_executable_dir(const char *argv0)
 {
 }
 
@@ -65,32 +267,28 @@ char *system_path(const char *path)
 	return strbuf_detach(&d, NULL);
 }
 
-void git_set_argv_exec_path(const char *exec_path)
+static const char *exec_path_value;
+
+void git_set_exec_path(const char *exec_path)
 {
-	argv_exec_path = exec_path;
+	exec_path_value = exec_path;
 	/*
 	 * Propagate this setting to external programs.
 	 */
 	setenv(EXEC_PATH_ENVIRONMENT, exec_path, 1);
 }
 
-
-/* Returns the highest-priority, location to look for git programs. */
+/* Returns the highest-priority location to look for git programs. */
 const char *git_exec_path(void)
 {
-	static char *cached_exec_path;
-
-	if (argv_exec_path)
-		return argv_exec_path;
-
-	if (!cached_exec_path) {
+	if (!exec_path_value) {
 		const char *env = getenv(EXEC_PATH_ENVIRONMENT);
 		if (env && *env)
-			cached_exec_path = xstrdup(env);
+			exec_path_value = xstrdup(env);
 		else
-			cached_exec_path = system_path(GIT_EXEC_PATH);
+			exec_path_value = system_path(GIT_EXEC_PATH);
 	}
-	return cached_exec_path;
+	return exec_path_value;
 }
 
 static void add_path(struct strbuf *out, const char *path)
@@ -103,10 +301,12 @@ static void add_path(struct strbuf *out, const char *path)
 
 void setup_path(void)
 {
+	const char *exec_path = git_exec_path();
 	const char *old_path = getenv("PATH");
 	struct strbuf new_path = STRBUF_INIT;
 
-	add_path(&new_path, git_exec_path());
+	git_set_exec_path(exec_path);
+	add_path(&new_path, exec_path);
 
 	if (old_path)
 		strbuf_addstr(&new_path, old_path);
@@ -125,7 +325,8 @@ const char **prepare_git_cmd(struct argv_array *out, const char **argv)
 	return out->argv;
 }
 
-int execv_git_cmd(const char **argv) {
+int execv_git_cmd(const char **argv)
+{
 	struct argv_array nargv = ARGV_ARRAY_INIT;
 
 	prepare_git_cmd(&nargv, argv);
@@ -140,8 +341,7 @@ int execv_git_cmd(const char **argv) {
 	return -1;
 }
 
-
-int execl_git_cmd(const char *cmd,...)
+int execl_git_cmd(const char *cmd, ...)
 {
 	int argc;
 	const char *argv[MAX_ARGS + 1];

exec_cmd.h

@@ -3,8 +3,8 @@
 
 struct argv_array;
 
-extern void git_set_argv_exec_path(const char *exec_path);
-extern void git_extract_argv0_path(const char *path);
+extern void git_set_exec_path(const char *exec_path);
+extern void git_resolve_executable_dir(const char *path);
 extern const char *git_exec_path(void);
 extern void setup_path(void);
 extern const char **prepare_git_cmd(struct argv_array *out, const char **argv);

gettext.c

@@ -2,7 +2,8 @@
  * Copyright (c) 2010 Ævar Arnfjörð Bjarmason
  */
 
-#include "git-compat-util.h"
+#include "cache.h"
+#include "exec_cmd.h"
 #include "gettext.h"
 #include "strbuf.h"
 #include "utf8.h"
@@ -159,15 +160,24 @@ static void init_gettext_charset(const char *domain)
 
 void git_setup_gettext(void)
 {
-	const char *podir = getenv("GIT_TEXTDOMAINDIR");
+	const char *podir = getenv(GIT_TEXT_DOMAIN_DIR_ENVIRONMENT);
+	char *p = NULL;
 
 	if (!podir)
-		podir = GIT_LOCALE_PATH;
+		podir = p = system_path(GIT_LOCALE_PATH);
+
+	if (!is_directory(podir)) {
+		free(p);
+		return;
+	}
+
 	bindtextdomain("git", podir);
 	setlocale(LC_MESSAGES, "");
 	setlocale(LC_TIME, "");
 	init_gettext_charset("git");
 	textdomain("git");
+
+	free(p);
 }
 
 /* return the number of columns of string 's' in current locale */

git.c

@@ -65,7 +65,7 @@ static int handle_options(const char ***argv, int *argc, int *envchanged)
 		 */
 		if (skip_prefix(cmd, "--exec-path", &cmd)) {
 			if (*cmd == '=')
-				git_set_argv_exec_path(cmd + 1);
+				git_set_exec_path(cmd + 1);
 			else {
 				puts(git_exec_path());
 				exit(0);

perl/Git/I18N.pm

@@ -18,7 +18,7 @@ our @EXPORT_OK = @EXPORT;
 
 sub __bootstrap_locale_messages {
 	our $TEXTDOMAIN = 'git';
-	our $TEXTDOMAINDIR = $ENV{GIT_TEXTDOMAINDIR} || '@@LOCALEDIR@@';
+	our $TEXTDOMAINDIR ||= $ENV{GIT_TEXTDOMAINDIR} || '@@LOCALEDIR@@';
 
 	require POSIX;
 	POSIX->import(qw(setlocale));

perl/header_templates/fixed_prefix.template.pl

@@ -0,0 +1 @@
+use lib (split(/@@PATHSEP@@/, $ENV{GITPERLLIB} || '@@INSTLIBDIR@@'));

perl/header_templates/runtime_prefix.template.pl

@@ -0,0 +1,42 @@
+# BEGIN RUNTIME_PREFIX generated code.
+#
+# This finds our Git::* libraries relative to the script's runtime path.
+sub __git_system_path {
+	my ($relpath) = @_;
+	my $gitexecdir_relative = '@@GITEXECDIR_REL@@';
+
+	# GIT_EXEC_PATH is supplied by `git` or the test suite.
+	my $exec_path;
+	if (exists $ENV{GIT_EXEC_PATH}) {
+		$exec_path = $ENV{GIT_EXEC_PATH};
+	} else {
+		# This can happen if this script is being directly invoked instead of run
+		# by "git".
+		require FindBin;
+		$exec_path = $FindBin::Bin;
+	}
+
+	# Trim off the relative gitexecdir path to get the system path.
+	(my $prefix = $exec_path) =~ s/\Q$gitexecdir_relative\E$//;
+
+	require File::Spec;
+	return File::Spec->catdir($prefix, $relpath);
+}
+
+BEGIN {
+	use lib split /@@PATHSEP@@/,
+	(
+		$ENV{GITPERLLIB} ||
+		do {
+			my $perllibdir = __git_system_path('@@PERLLIBDIR_REL@@');
+			(-e $perllibdir) || die("Invalid system path ($relpath): $path");
+			$perllibdir;
+		}
+	);
+
+	# Export the system locale directory to the I18N module. The locale directory
+	# is only installed if NO_GETTEXT is set.
+	$Git::I18N::TEXTDOMAINDIR = __git_system_path('@@LOCALEDIR_REL@@');
+}
+
+# END RUNTIME_PREFIX generated code.

t/t0061-run-command.sh

@@ -149,7 +149,7 @@ test_trace () {
 	expect="$1"
 	shift
 	GIT_TRACE=1 test-run-command "$@" run-command true 2>&1 >/dev/null | \
-		sed 's/.* run_command: //' >actual &&
+		sed -e 's/.* run_command: //' -e '/trace: .*/d' >actual &&
 	echo "$expect true" >expect &&
 	test_cmp expect actual
 }