common-main: call git_extract_argv0_path()

Every program which links against libgit.a must call this
function, or risk hitting an assert() in system_path() that
checks whether we have configured argv0_path (though only
when RUNTIME_PREFIX is defined, so essentially only on
Windows).

Looking at the diff, you can see that putting it into the
common main() saves us having to do it individually in each
of the external commands. But what you can't see are the
cases where we _should_ have been doing so, but weren't
(e.g., git-credential-store, and all of the t/helper test
programs).

This has been an accident-waiting-to-happen for a long time,
but wasn't triggered until recently because it involves one
of those programs actually calling system_path(). That
happened with git-credential-store in v2.8.0 with ae5f677
(lazily load core.sharedrepository, 2016-03-11). The
program:

  - takes a lock file, which...

  - opens a tempfile, which...

  - calls adjust_shared_perm to fix permissions, which...

  - lazy-loads the config (as of ae5f677), which...

  - calls system_path() to find the location of
    /etc/gitconfig

On systems with RUNTIME_PREFIX, this means credential-store
reliably hits that assert() and cannot be used.

We never noticed in the test suite, because we set
GIT_CONFIG_NOSYSTEM there, which skips the system_path()
lookup entirely.  But if we were to tweak git_config() to
find /etc/gitconfig even when we aren't going to open it,
then the test suite shows multiple failures (for
credential-store, and for some other test helpers). I didn't
include that tweak here because it's way too specific to
this particular call to be worth carrying around what is
essentially dead code.

The implementation is fairly straightforward, with one
exception: there is exactly one caller (git.c) that actually
cares about the result of the function, and not the
side-effect of setting up argv0_path. We can accommodate
that by simply replacing the value of argv[0] in the array
we hand down to cmd_main().

Signed-off-by: Jeff King <peff@peff.net>

12 files changed, 4 insertions, 19 deletions

diff --git a/common-main.c b/common-main.c
index 80d59566e3..87964b62db 100644
--- a/common-main.c
+++ b/common-main.c
@@ -1,6 +1,9 @@
 #include "git-compat-util.h"
+#include "exec_cmd.h"
 
 int main(int argc, const char **argv)
 {
+	argv[0] = git_extract_argv0_path(argv[0]);
+
 	return cmd_main(argc, argv);
 }
diff --git a/daemon.c b/daemon.c
index 4326cd0314..d33ee5a146 100644
--- a/daemon.c
+++ b/daemon.c
@@ -1,6 +1,5 @@
 #include "cache.h"
 #include "pkt-line.h"
-#include "exec_cmd.h"
 #include "run-command.h"
 #include "strbuf.h"
 #include "string-list.h"
@@ -1204,8 +1203,6 @@ int cmd_main(int argc, const char **argv)
 
 	git_setup_gettext();
 
-	git_extract_argv0_path(argv[0]);
-
 	for (i = 1; i < argc; i++) {
 		const char *arg = argv[i];
 		const char *v;
diff --git a/fast-import.c b/fast-import.c
index 7cb7434e7e..f12cd00e09 100644
--- a/fast-import.c
+++ b/fast-import.c
@@ -164,7 +164,6 @@ Format of STDIN stream:
 #include "refs.h"
 #include "csum-file.h"
 #include "quote.h"
-#include "exec_cmd.h"
 #include "dir.h"
 #include "run-command.h"
 
@@ -3449,8 +3448,6 @@ int cmd_main(int argc, const char **argv)
 {
 	unsigned int i;
 
-	git_extract_argv0_path(argv[0]);
-
 	git_setup_gettext();
 
 	if (argc == 2 && !strcmp(argv[1], "-h"))
diff --git a/git.c b/git.c
index e2444046f5..3b4e12d7c6 100644
--- a/git.c
+++ b/git.c
@@ -635,7 +635,7 @@ int cmd_main(int argc, const char **argv)
 	const char *cmd;
 	int done_help = 0;
 
-	cmd = git_extract_argv0_path(argv[0]);
+	cmd = argv[0];
 	if (!cmd)
 		cmd = "git-help";
 
diff --git a/http-backend.c b/http-backend.c
index 411c835a5c..5375cbc83c 100644
--- a/http-backend.c
+++ b/http-backend.c
@@ -642,7 +642,6 @@ int cmd_main(int argc, const char **argv)
 
 	git_setup_gettext();
 
-	git_extract_argv0_path(argv[0]);
 	set_die_routine(die_webcgi);
 	set_die_is_recursing_routine(die_webcgi_recursing);
 
diff --git a/http-fetch.c b/http-fetch.c
index eb559eb83b..244cd0db5d 100644
--- a/http-fetch.c
+++ b/http-fetch.c
@@ -24,8 +24,6 @@ int cmd_main(int argc, const char **argv)
 
 	git_setup_gettext();
 
-	git_extract_argv0_path(argv[0]);
-
 	while (arg < argc && argv[arg][0] == '-') {
 		if (argv[arg][1] == 't') {
 			get_tree = 1;
diff --git a/http-push.c b/http-push.c
index df20e44ba4..3a5fecfaa1 100644
--- a/http-push.c
+++ b/http-push.c
@@ -1711,8 +1711,6 @@ int cmd_main(int argc, const char **argv)
 
 	git_setup_gettext();
 
-	git_extract_argv0_path(argv[0]);
-
 	repo = xcalloc(1, sizeof(*repo));
 
 	argv++;
diff --git a/imap-send.c b/imap-send.c
index 890e1cbb64..125b2183a7 100644
--- a/imap-send.c
+++ b/imap-send.c
@@ -1500,8 +1500,6 @@ int cmd_main(int argc, const char **argv)
 	int total;
 	int nongit_ok;
 
-	git_extract_argv0_path(argv[0]);
-
 	git_setup_gettext();
 
 	setup_git_directory_gently(&nongit_ok);
diff --git a/remote-curl.c b/remote-curl.c
index a068340487..d39f4cf8a6 100644
--- a/remote-curl.c
+++ b/remote-curl.c
@@ -991,7 +991,6 @@ int cmd_main(int argc, const char **argv)
 
 	git_setup_gettext();
 
-	git_extract_argv0_path(argv[0]);
 	setup_git_directory_gently(&nongit);
 	if (argc < 2) {
 		error("remote-curl: usage: git remote-curl <remote> [<url>]");
diff --git a/remote-testsvn.c b/remote-testsvn.c
index 32631eb14a..f87bf851ba 100644
--- a/remote-testsvn.c
+++ b/remote-testsvn.c
@@ -292,7 +292,6 @@ int cmd_main(int argc, const char **argv)
 	static struct remote *remote;
 	const char *url_in;
 
-	git_extract_argv0_path(argv[0]);
 	setup_git_directory();
 	if (argc < 2 || argc > 3) {
 		usage("git-remote-svn <remote-name> [<url>]");
diff --git a/shell.c b/shell.c
index 3dd7fdcfe6..ca00807d7e 100644
--- a/shell.c
+++ b/shell.c
@@ -147,8 +147,6 @@ int cmd_main(int argc, const char **argv)
 
 	git_setup_gettext();
 
-	git_extract_argv0_path(argv[0]);
-
 	/*
 	 * Always open file descriptors 0/1/2 to avoid clobbering files
 	 * in die().  It also avoids messing up when the pipes are dup'ed
diff --git a/upload-pack.c b/upload-pack.c
index 80dda752e6..681fd2f2bc 100644
--- a/upload-pack.c
+++ b/upload-pack.c
@@ -839,7 +839,6 @@ int cmd_main(int argc, const char **argv)
 	git_setup_gettext();
 
 	packet_trace_identity("upload-pack");
-	git_extract_argv0_path(argv[0]);
 	check_replace_refs = 0;
 
 	argc = parse_options(argc, argv, NULL, options, upload_pack_usage, 0);