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tree-wide: drop support for kernels without pidfd_open() and pidfd_send_signal() (#35971)

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This commit is contained in:
Lennart Poettering
2025-01-16 11:37:17 +01:00
committed by GitHub
parent 39706728e1 e755cde735
commit 9ef559a036
7 changed files with 71 additions and 163 deletions
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src/basic/process-util.c
+31 -40
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@@ -2042,7 +2042,7 @@ int posix_spawn_wrapper(
* issues.
*
* Also, move the newly-created process into 'cgroup' through POSIX_SPAWN_SETCGROUP (clone3())
* if available. Note that CLONE_INTO_CGROUP is only supported on cgroup v2.
* if available.
* returns 1: We're already in the right cgroup
* 0: 'cgroup' not specified or POSIX_SPAWN_SETCGROUP is not supported. The caller
* needs to call 'cg_attach' on their own */
@@ -2061,14 +2061,10 @@ int posix_spawn_wrapper(
_unused_ _cleanup_(posix_spawnattr_destroyp) posix_spawnattr_t *attr_destructor = &attr;
#if HAVE_PIDFD_SPAWN
static enum {
CLONE_ONLY_PID,
CLONE_CAN_PIDFD, /* 5.2 */
CLONE_CAN_CGROUP, /* 5.7 */
} clone_support = CLONE_CAN_CGROUP;
static bool have_clone_into_cgroup = true; /* kernel 5.7+ */
_cleanup_close_ int cgroup_fd = -EBADF;
if (cgroup && clone_support >= CLONE_CAN_CGROUP) {
if (cgroup && have_clone_into_cgroup) {
_cleanup_free_ char *resolved_cgroup = NULL;
r = cg_get_path_and_check(
@@ -2099,47 +2095,41 @@ int posix_spawn_wrapper(
return -r;
#if HAVE_PIDFD_SPAWN
if (clone_support >= CLONE_CAN_PIDFD) {
_cleanup_close_ int pidfd = -EBADF;
_cleanup_close_ int pidfd = -EBADF;
r = pidfd_spawn(&pidfd, path, NULL, &attr, argv, envp);
if (ERRNO_IS_NOT_SUPPORTED(r) && FLAGS_SET(flags, POSIX_SPAWN_SETCGROUP) &&
cg_is_threaded(cgroup) > 0) /* clone3() could also return EOPNOTSUPP if the target cgroup is in threaded mode. */
return -EUCLEAN;
if ((ERRNO_IS_NOT_SUPPORTED(r) || ERRNO_IS_PRIVILEGE(r) || r == E2BIG) &&
FLAGS_SET(flags, POSIX_SPAWN_SETCGROUP)) {
/* Compiled on a newer host, or seccomp&friends blocking clone3()? Fallback, but
* need to disable POSIX_SPAWN_SETCGROUP, which is what redirects to clone3().
* Note that we might get E2BIG here since some kernels (e.g. 5.4) support clone3()
* but not CLONE_INTO_CGROUP. */
r = pidfd_spawn(&pidfd, path, NULL, &attr, argv, envp);
if (ERRNO_IS_NOT_SUPPORTED(r) && FLAGS_SET(flags, POSIX_SPAWN_SETCGROUP) && cg_is_threaded(cgroup) > 0)
return -EUCLEAN; /* clone3() could also return EOPNOTSUPP if the target cgroup is in threaded mode,
turn that into something recognizable */
if ((ERRNO_IS_NOT_SUPPORTED(r) || ERRNO_IS_PRIVILEGE(r) || r == E2BIG) &&
FLAGS_SET(flags, POSIX_SPAWN_SETCGROUP)) {
/* Compiled on a newer host, or seccomp&friends blocking clone3()? Fallback, but
* need to disable POSIX_SPAWN_SETCGROUP, which is what redirects to clone3().
* Note that we might get E2BIG here since some kernels (e.g. 5.4) support clone3()
* but not CLONE_INTO_CGROUP. */
/* CLONE_INTO_CGROUP definitely won't work, hence remember the fact so that we don't
* retry every time. */
assert(clone_support >= CLONE_CAN_CGROUP);
clone_support = CLONE_CAN_PIDFD;
/* CLONE_INTO_CGROUP definitely won't work, hence remember the fact so that we don't
* retry every time. */
have_clone_into_cgroup = false;
flags &= ~POSIX_SPAWN_SETCGROUP;
r = posix_spawnattr_setflags(&attr, flags);
if (r != 0)
return -r;
r = pidfd_spawn(&pidfd, path, NULL, &attr, argv, envp);
}
if (r == 0) {
r = pidref_set_pidfd_consume(ret_pidref, TAKE_FD(pidfd));
if (r < 0)
return r;
return FLAGS_SET(flags, POSIX_SPAWN_SETCGROUP);
}
if (!ERRNO_IS_NOT_SUPPORTED(r) && !ERRNO_IS_PRIVILEGE(r))
flags &= ~POSIX_SPAWN_SETCGROUP;
r = posix_spawnattr_setflags(&attr, flags);
if (r != 0)
return -r;
clone_support = CLONE_ONLY_PID; /* No CLONE_PIDFD either? */
r = pidfd_spawn(&pidfd, path, NULL, &attr, argv, envp);
}
#endif
if (r != 0)
return -r;
r = pidref_set_pidfd_consume(ret_pidref, TAKE_FD(pidfd));
if (r < 0)
return r;
return FLAGS_SET(flags, POSIX_SPAWN_SETCGROUP);
#else
pid_t pid;
r = posix_spawn(&pid, path, NULL, &attr, argv, envp);
if (r != 0)
return -r;
@@ -2149,6 +2139,7 @@ int posix_spawn_wrapper(
return r;
return 0; /* We did not use CLONE_INTO_CGROUP so return 0, the caller will have to move the child */
#endif
}
int proc_dir_open(DIR **ret) {