[PATCH 3/3] daemon: free listen_addr before returning
From: Jeff King <hidden>
Date: 2023-10-05 21:33:32
Subsystem:
the rest · Maintainer:
Linus Torvalds
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 <redacted>
---
Diff is a little messy due to indentation. Viewing with "-w" makes it
more clear, or just viewing the post-image.
daemon.c | 37 ++++++++++++++++++++----------------
t/t5811-proto-disable-git.sh | 2 ++
2 files changed, 23 insertions(+), 16 deletions(-)
diff --git a/daemon.c b/daemon.c
index f5e597114b..17d331b2f3 100644
--- a/daemon.c
+++ b/daemon.c@@ -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()); - 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]); - /* 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); + } - return serve(&listen_addr, listen_port, cred); + string_list_clear(&listen_addr, 0); + return ret; }
diff --git a/t/t5811-proto-disable-git.sh b/t/t5811-proto-disable-git.sh
index 8ac6b2a1d0..ed773e7432 100755
--- a/t/t5811-proto-disable-git.sh
+++ b/t/t5811-proto-disable-git.sh@@ -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"
--
2.42.0.836.g4b88bf80c5