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git/credential-cache.c
Jeff King 3f2e2297b9 add an extra level of indirection to main() 
There are certain startup tasks that we expect every git
process to do. In some cases this is just to improve the
quality of the program (e.g., setting up gettext()). In
others it is a requirement for using certain functions in
libgit.a (e.g., system_path() expects that you have called
git_extract_argv0_path()).

Most commands are builtins and are covered by the git.c
version of main(). However, there are still a few external
commands that use their own main(). Each of these has to
remember to include the correct startup sequence, and we are
not always consistent.

Rather than just fix the inconsistencies, let's make this
harder to get wrong by providing a common main() that can
run this standard startup.

We basically have two options to do this:

 - the compat/mingw.h file already does something like this by
   adding a #define that replaces the definition of main with a
   wrapper that calls mingw_startup().

   The upside is that the code in each program doesn't need
   to be changed at all; it's rewritten on the fly by the
   preprocessor.

   The downside is that it may make debugging of the startup
   sequence a bit more confusing, as the preprocessor is
   quietly inserting new code.

 - the builtin functions are all of the form cmd_foo(),
   and git.c's main() calls them.

   This is much more explicit, which may make things more
   obvious to somebody reading the code. It's also more
   flexible (because of course we have to figure out _which_
   cmd_foo() to call).

   The downside is that each of the builtins must define
   cmd_foo(), instead of just main().

This patch chooses the latter option, preferring the more
explicit approach, even though it is more invasive. We
introduce a new file common-main.c, with the "real" main. It
expects to call cmd_main() from whatever other objects it is
linked against.

We link common-main.o against anything that links against
libgit.a, since we know that such programs will need to do
this setup. Note that common-main.o can't actually go inside
libgit.a, as the linker would not pick up its main()
function automatically (it has no callers).

The rest of the patch is just adjusting all of the various
external programs (mostly in t/helper) to use cmd_main().
I've provided a global declaration for cmd_main(), which
means that all of the programs also need to match its
signature. In particular, many functions need to switch to
"const char **" instead of "char **" for argv. This effect
ripples out to a few other variables and functions, as well.

This makes the patch even more invasive, but the end result
is much better. We should be treating argv strings as const
anyway, and now all programs conform to the same signature
(which also matches the way builtins are defined).

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-07-01 15:09:10 -07:00

124 lines
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#include "cache.h"
#include "credential.h"
#include "string-list.h"
#include "parse-options.h"
#include "unix-socket.h"
#include "run-command.h"
#define FLAG_SPAWN 0x1
#define FLAG_RELAY 0x2
static int send_request(const char *socket, const struct strbuf *out)
{
int got_data = 0;
int fd = unix_stream_connect(socket);
if (fd < 0)
return -1;
if (write_in_full(fd, out->buf, out->len) < 0)
die_errno("unable to write to cache daemon");
shutdown(fd, SHUT_WR);
while (1) {
char in[1024];
int r;
r = read_in_full(fd, in, sizeof(in));
if (r == 0)
break;
if (r < 0)
die_errno("read error from cache daemon");
write_or_die(1, in, r);
got_data = 1;
}
close(fd);
return got_data;
}
static void spawn_daemon(const char *socket)
{
struct child_process daemon = CHILD_PROCESS_INIT;
const char *argv[] = { NULL, NULL, NULL };
char buf[128];
int r;
argv[0] = "git-credential-cache--daemon";
argv[1] = socket;
daemon.argv = argv;
daemon.no_stdin = 1;
daemon.out = -1;
if (start_command(&daemon))
die_errno("unable to start cache daemon");
r = read_in_full(daemon.out, buf, sizeof(buf));
if (r < 0)
die_errno("unable to read result code from cache daemon");
if (r != 3 || memcmp(buf, "ok\n", 3))
die("cache daemon did not start: %.*s", r, buf);
close(daemon.out);
}
static void do_cache(const char *socket, const char *action, int timeout,
int flags)
{
struct strbuf buf = STRBUF_INIT;
strbuf_addf(&buf, "action=%s\n", action);
strbuf_addf(&buf, "timeout=%d\n", timeout);
if (flags & FLAG_RELAY) {
if (strbuf_read(&buf, 0, 0) < 0)
die_errno("unable to relay credential");
}
if (send_request(socket, &buf) < 0) {
if (errno != ENOENT && errno != ECONNREFUSED)
die_errno("unable to connect to cache daemon");
if (flags & FLAG_SPAWN) {
spawn_daemon(socket);
if (send_request(socket, &buf) < 0)
die_errno("unable to connect to cache daemon");
}
}
strbuf_release(&buf);
}
int cmd_main(int argc, const char **argv)
{
char *socket_path = NULL;
int timeout = 900;
const char *op;
const char * const usage[] = {
"git credential-cache [<options>] <action>",
NULL
};
struct option options[] = {
OPT_INTEGER(0, "timeout", &timeout,
"number of seconds to cache credentials"),
OPT_STRING(0, "socket", &socket_path, "path",
"path of cache-daemon socket"),
OPT_END()
};
argc = parse_options(argc, argv, NULL, options, usage, 0);
if (!argc)
usage_with_options(usage, options);
op = argv[0];
if (!socket_path)
socket_path = expand_user_path("~/.git-credential-cache/socket");
if (!socket_path)
die("unable to find a suitable socket path; use --socket");
if (!strcmp(op, "exit"))
do_cache(socket_path, op, timeout, 0);
else if (!strcmp(op, "get") || !strcmp(op, "erase"))
do_cache(socket_path, op, timeout, FLAG_RELAY);
else if (!strcmp(op, "store"))
do_cache(socket_path, op, timeout, FLAG_RELAY|FLAG_SPAWN);
else
; /* ignore unknown operation */
return 0;
}
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