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core/exec-invoke: make fd array sizing less error-prone

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History has clearly shown that we're terrible at keeping
the size of the dont_close array up-to-date. Hence let's
step away from a hardcoded max size for that, instead
always collect all fds in the array initializer and
let compiler figure it out, taking advantage of the fact
that close_all_fds() gracefully handles invalid fds in
the 'except' array.
This commit is contained in:
Mike Yuan
2026-03-01 13:55:39 +01:00
parent f2e7ba1074
commit eb8df25a37
1 changed files with 27 additions and 47 deletions
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src/core/exec-invoke.c
+27 -47
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@@ -4274,68 +4274,48 @@ out:
return r;
}
static void append_socket_pair(int *array, size_t *n, const int pair[static 2]) {
assert(array);
assert(n);
assert(pair);
#define FD_PAIR_CONDITION(cond, pair) \
(cond) ? pair[0] : -EBADF, (cond) ? pair[1] : -EBADF
if (pair[0] >= 0)
array[(*n)++] = pair[0];
if (pair[1] >= 0)
array[(*n)++] = pair[1];
}
#define FD_PAIR(pair) FD_PAIR_CONDITION(true, pair)
static int close_remaining_fds(
const ExecParameters *params,
const ExecRuntime *runtime,
int socket_fd,
const int *fds,
const int fds[],
size_t n_fds) {
size_t n_dont_close = 0;
int dont_close[n_fds + 18];
assert(params);
assert(runtime);
assert(fds || n_fds == 0);
if (params->stdin_fd >= 0)
dont_close[n_dont_close++] = params->stdin_fd;
if (params->stdout_fd >= 0)
dont_close[n_dont_close++] = params->stdout_fd;
if (params->stderr_fd >= 0)
dont_close[n_dont_close++] = params->stderr_fd;
/* fds listed here shall be closed before second close_all_fds() call to avoid double close! */
int static_fds[] = {
params->stdin_fd, params->stdout_fd, params->stderr_fd,
socket_fd,
FD_PAIR(runtime->ephemeral_storage_socket),
FD_PAIR_CONDITION(runtime->shared, runtime->shared->userns_storage_socket),
FD_PAIR_CONDITION(runtime->shared, runtime->shared->netns_storage_socket),
FD_PAIR_CONDITION(runtime->shared, runtime->shared->ipcns_storage_socket),
FD_PAIR_CONDITION(runtime->dynamic_creds && runtime->dynamic_creds->user,
runtime->dynamic_creds->user->storage_socket),
FD_PAIR_CONDITION(runtime->dynamic_creds && runtime->dynamic_creds->group,
runtime->dynamic_creds->group->storage_socket),
params->user_lookup_fd,
params->pidref_transport_fd,
};
if (socket_fd >= 0)
dont_close[n_dont_close++] = socket_fd;
_cleanup_free_ int *accum_fds = NULL;
if (n_fds > 0) {
memcpy(dont_close + n_dont_close, fds, sizeof(int) * n_fds);
n_dont_close += n_fds;
accum_fds = new(int, ELEMENTSOF(static_fds) + n_fds);
if (!accum_fds)
return -ENOMEM;
memcpy(mempcpy_typesafe(accum_fds, static_fds, ELEMENTSOF(static_fds)), fds, sizeof(int) * n_fds);
}
append_socket_pair(dont_close, &n_dont_close, runtime->ephemeral_storage_socket);
if (runtime->shared) {
append_socket_pair(dont_close, &n_dont_close, runtime->shared->userns_storage_socket);
append_socket_pair(dont_close, &n_dont_close, runtime->shared->netns_storage_socket);
append_socket_pair(dont_close, &n_dont_close, runtime->shared->ipcns_storage_socket);
}
if (runtime->dynamic_creds) {
if (runtime->dynamic_creds->user)
append_socket_pair(dont_close, &n_dont_close, runtime->dynamic_creds->user->storage_socket);
if (runtime->dynamic_creds->group)
append_socket_pair(dont_close, &n_dont_close, runtime->dynamic_creds->group->storage_socket);
}
if (params->user_lookup_fd >= 0)
dont_close[n_dont_close++] = params->user_lookup_fd;
if (params->pidref_transport_fd >= 0)
dont_close[n_dont_close++] = params->pidref_transport_fd;
assert(n_dont_close <= ELEMENTSOF(dont_close));
return close_all_fds(dont_close, n_dont_close);
return close_all_fds(accum_fds ?: static_fds, ELEMENTSOF(static_fds) + n_fds);
}
static int send_user_lookup(