daemon: free listen_addr before returning

We build up a string list of listen addresses from the command-line
arguments, but never free it. This causes t5811 to complain of a leak
(though curiously it seems to do so only when compiled with gcc, not
with clang).

To handle this correctly, we have to do a little refactoring:

  - there are two exit points from the main function, depending on
    whether we are entering the main loop or serving a single client
    (since rather than a traditional fork model, we re-exec ourselves
    with the extra "--serve" argument to accommodate Windows).

    We don't need --listen at all in the --serve case, of course, but it
    is passed along by the parent daemon, which simply copies all of the
    command-line options it got.

  - we just "return serve()" to run the main loop, giving us no chance
    to do any cleanup

So let's use a "ret" variable to store the return code, and give
ourselves a single exit point at the end. That gives us one place to do
cleanup.

Note that this code also uses the "use a no-dup string-list, but
allocate strings we add to it" trick, meaning string_list_clear() will
not realize it should free them. We can fix this by switching to a "dup"
string-list, but using the "append_nodup" function to add to it (this is
preferable to tweaking the strdup_strings flag before clearing, as it
puts all the subtle memory-ownership code together).

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This commit is contained in:
Jeff King 2023-10-05 17:33:26 -04:00 committed by Junio C Hamano
parent 8ef8da4842
commit badf2fe1c3
2 changed files with 24 additions and 17 deletions

View file

@ -1243,19 +1243,20 @@ static int serve(struct string_list *listen_addr, int listen_port,
int cmd_main(int argc, const char **argv)
{
int listen_port = 0;
struct string_list listen_addr = STRING_LIST_INIT_NODUP;
struct string_list listen_addr = STRING_LIST_INIT_DUP;
int serve_mode = 0, inetd_mode = 0;
const char *pid_file = NULL, *user_name = NULL, *group_name = NULL;
int detach = 0;
struct credentials *cred = NULL;
int i;
int ret;
for (i = 1; i < argc; i++) {
const char *arg = argv[i];
const char *v;
if (skip_prefix(arg, "--listen=", &v)) {
string_list_append(&listen_addr, xstrdup_tolower(v));
string_list_append_nodup(&listen_addr, xstrdup_tolower(v));
continue;
}
if (skip_prefix(arg, "--port=", &v)) {
@ -1437,22 +1438,26 @@ int cmd_main(int argc, const char **argv)
die_errno("failed to redirect stderr to /dev/null");
}
if (inetd_mode || serve_mode)
return execute();
if (inetd_mode || serve_mode) {
ret = execute();
} else {
if (detach) {
if (daemonize())
die("--detach not supported on this platform");
}
if (detach) {
if (daemonize())
die("--detach not supported on this platform");
if (pid_file)
write_file(pid_file, "%"PRIuMAX, (uintmax_t) getpid());
/* prepare argv for serving-processes */
strvec_push(&cld_argv, argv[0]); /* git-daemon */
strvec_push(&cld_argv, "--serve");
for (i = 1; i < argc; ++i)
strvec_push(&cld_argv, argv[i]);
ret = serve(&listen_addr, listen_port, cred);
}
if (pid_file)
write_file(pid_file, "%"PRIuMAX, (uintmax_t) getpid());
/* prepare argv for serving-processes */
strvec_push(&cld_argv, argv[0]); /* git-daemon */
strvec_push(&cld_argv, "--serve");
for (i = 1; i < argc; ++i)
strvec_push(&cld_argv, argv[i]);
return serve(&listen_addr, listen_port, cred);
string_list_clear(&listen_addr, 0);
return ret;
}

View file

@ -1,6 +1,8 @@
#!/bin/sh
test_description='test disabling of git-over-tcp in clone/fetch'
TEST_PASSES_SANITIZE_LEAK=true
. ./test-lib.sh
. "$TEST_DIRECTORY/lib-proto-disable.sh"
. "$TEST_DIRECTORY/lib-git-daemon.sh"