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core/service: support sd_notify() MAINPIDFD=1 and MAINPIDFDID= (#34932)

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This commit is contained in:
Lennart Poettering
2024-10-30 08:45:25 +01:00
committed by GitHub
parent eae9e74f35 c3ecb747f1
commit 5c11f6e0a9
6 changed files with 183 additions and 79 deletions
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src/core/service.c
+89 -27
View File
@@ -4540,6 +4540,72 @@ static bool service_notify_message_authorized(Service *s, PidRef *pid) {
}
}
static int service_notify_message_parse_new_pid(
Unit *u,
char * const *tags,
FDSet *fds,
PidRef *ret) {
_cleanup_(pidref_done) PidRef pidref = PIDREF_NULL;
const char *e;
int r;
assert(u);
assert(ret);
/* MAINPIDFD=1 always takes precedence */
if (strv_contains(tags, "MAINPIDFD=1")) {
unsigned n_fds = fdset_size(fds);
if (n_fds != 1)
return log_unit_warning_errno(u, SYNTHETIC_ERRNO(EINVAL),
"Got MAINPIDFD=1 with %s fd, ignoring.", n_fds == 0 ? "no" : "more than one");
r = pidref_set_pidfd_consume(&pidref, ASSERT_FD(fdset_steal_first(fds)));
if (r < 0)
return log_unit_warning_errno(u, r, "Failed to create reference to received new main pidfd: %m");
goto finish;
}
e = strv_find_startswith(tags, "MAINPID=");
if (!e) {
*ret = PIDREF_NULL;
return 0;
}
r = pidref_set_pidstr(&pidref, e);
if (r < 0)
return log_unit_warning_errno(u, r, "Failed to parse MAINPID=%s field in notification message, ignoring: %m", e);
e = strv_find_startswith(tags, "MAINPIDFDID=");
if (!e)
goto finish;
uint64_t pidfd_id;
r = safe_atou64(e, &pidfd_id);
if (r < 0)
return log_unit_warning_errno(u, r, "Failed to parse MAINPIDFDID= in notification message, refusing: %s", e);
r = pidref_acquire_pidfd_id(&pidref);
if (r < 0) {
if (!ERRNO_IS_NEG_NOT_SUPPORTED(r))
log_unit_warning_errno(u, r,
"Failed to acquire pidfd id of process " PID_FMT ", not validating MAINPIDFDID=%" PRIu64 ": %m",
pidref.pid, pidfd_id);
goto finish;
}
if (pidref.fd_id != pidfd_id)
return log_unit_warning_errno(u, SYNTHETIC_ERRNO(ESRCH),
"PIDFD ID of process " PID_FMT " (%" PRIu64 ") mismatches with received MAINPIDFDID=%" PRIu64 ", not changing main PID.",
pidref.pid, pidref.fd_id, pidfd_id);
finish:
*ret = TAKE_PIDREF(pidref);
return 1;
}
static void service_notify_message(
Unit *u,
PidRef *pidref,
@@ -4565,38 +4631,34 @@ static void service_notify_message(
bool notify_dbus = false;
const char *e;
/* Interpret MAINPID= */
e = strv_find_startswith(tags, "MAINPID=");
if (e && IN_SET(s->state, SERVICE_START, SERVICE_START_POST, SERVICE_RUNNING,
SERVICE_RELOAD, SERVICE_RELOAD_SIGNAL, SERVICE_RELOAD_NOTIFY,
SERVICE_STOP, SERVICE_STOP_SIGTERM)) {
/* Interpret MAINPID= (+ MAINPIDFDID=) / MAINPIDFD=1 */
_cleanup_(pidref_done) PidRef new_main_pid = PIDREF_NULL;
_cleanup_(pidref_done) PidRef new_main_pid = PIDREF_NULL;
r = service_notify_message_parse_new_pid(u, tags, fds, &new_main_pid);
if (r > 0 &&
IN_SET(s->state, SERVICE_START, SERVICE_START_POST, SERVICE_RUNNING,
SERVICE_RELOAD, SERVICE_RELOAD_SIGNAL, SERVICE_RELOAD_NOTIFY,
SERVICE_STOP, SERVICE_STOP_SIGTERM) &&
(!s->main_pid_known || !pidref_equal(&new_main_pid, &s->main_pid))) {
r = pidref_set_pidstr(&new_main_pid, e);
if (r < 0)
log_unit_warning_errno(u, r, "Failed to parse MAINPID=%s field in notification message, ignoring: %m", e);
else if (!s->main_pid_known || !pidref_equal(&new_main_pid, &s->main_pid)) {
r = service_is_suitable_main_pid(s, &new_main_pid, LOG_WARNING);
if (r == 0) {
/* The new main PID is a bit suspicious, which is OK if the sender is privileged. */
r = service_is_suitable_main_pid(s, &new_main_pid, LOG_WARNING);
if (r == 0) {
/* The new main PID is a bit suspicious, which is OK if the sender is privileged. */
if (ucred->uid == 0) {
log_unit_debug(u, "New main PID "PID_FMT" does not belong to service, but we'll accept it as the request to change it came from a privileged process.", new_main_pid.pid);
r = 1;
} else
log_unit_warning(u, "New main PID "PID_FMT" does not belong to service, refusing.", new_main_pid.pid);
}
if (r > 0) {
(void) service_set_main_pidref(s, TAKE_PIDREF(new_main_pid), /* start_timestamp = */ NULL);
if (ucred->uid == 0) {
log_unit_debug(u, "New main PID "PID_FMT" does not belong to service, but we'll accept it as the request to change it came from a privileged process.", new_main_pid.pid);
r = 1;
} else
log_unit_warning(u, "New main PID "PID_FMT" does not belong to service, refusing.", new_main_pid.pid);
}
if (r > 0) {
(void) service_set_main_pidref(s, TAKE_PIDREF(new_main_pid), /* start_timestamp = */ NULL);
r = unit_watch_pidref(UNIT(s), &s->main_pid, /* exclusive= */ false);
if (r < 0)
log_unit_warning_errno(UNIT(s), r, "Failed to watch new main PID "PID_FMT" for service: %m", s->main_pid.pid);
r = unit_watch_pidref(UNIT(s), &s->main_pid, /* exclusive= */ false);
if (r < 0)
log_unit_warning_errno(UNIT(s), r, "Failed to watch new main PID "PID_FMT" for service: %m", s->main_pid.pid);
notify_dbus = true;
}
notify_dbus = true;
}
}
src/notify/notify.c
+48 -26
View File
@@ -28,7 +28,7 @@
static bool arg_ready = false;
static bool arg_reloading = false;
static bool arg_stopping = false;
static pid_t arg_pid = 0;
static PidRef arg_pid = PIDREF_NULL;
static const char *arg_status = NULL;
static bool arg_booted = false;
static uid_t arg_uid = UID_INVALID;
@@ -39,6 +39,7 @@ static char **arg_exec = NULL;
static FDSet *arg_fds = NULL;
static char *arg_fdname = NULL;
STATIC_DESTRUCTOR_REGISTER(arg_pid, pidref_done);
STATIC_DESTRUCTOR_REGISTER(arg_env, strv_freep);
STATIC_DESTRUCTOR_REGISTER(arg_exec, strv_freep);
STATIC_DESTRUCTOR_REGISTER(arg_fds, fdset_freep);
@@ -99,16 +100,24 @@ static pid_t manager_pid(void) {
return pid;
}
static pid_t pid_parent_if_possible(void) {
pid_t parent_pid = getppid();
static int pidref_parent_if_applicable(PidRef *ret) {
_cleanup_(pidref_done) PidRef pidref = PIDREF_NULL;
int r;
assert(ret);
r = pidref_set_parent(&pidref);
if (r < 0)
return log_debug_errno(r, "Failed to create reference to our parent process: %m");
/* Don't send from PID 1 or the service manager's PID (which might be distinct from 1, if we are a
* --user service). That'd just be confusing for the service manager. */
if (parent_pid <= 1 ||
parent_pid == manager_pid())
return getpid_cached();
if (pidref.pid <= 1 ||
pidref.pid == manager_pid())
return pidref_set_self(ret);
return parent_pid;
*ret = TAKE_PIDREF(pidref);
return 0;
}
static int parse_argv(int argc, char *argv[]) {
@@ -175,17 +184,18 @@ static int parse_argv(int argc, char *argv[]) {
break;
case ARG_PID:
pidref_done(&arg_pid);
if (isempty(optarg) || streq(optarg, "auto"))
arg_pid = pid_parent_if_possible();
r = pidref_parent_if_applicable(&arg_pid);
else if (streq(optarg, "parent"))
arg_pid = getppid();
r = pidref_set_parent(&arg_pid);
else if (streq(optarg, "self"))
arg_pid = getpid_cached();
else {
r = parse_pid(optarg, &arg_pid);
if (r < 0)
return log_error_errno(r, "Failed to parse PID %s.", optarg);
}
r = pidref_set_self(&arg_pid);
else
r = pidref_set_pidstr(&arg_pid, optarg);
if (r < 0)
return log_error_errno(r, "Failed to refer to --pid='%s': %m", optarg);
break;
@@ -276,7 +286,7 @@ static int parse_argv(int argc, char *argv[]) {
if (arg_fdname && fdset_isempty(arg_fds))
return log_error_errno(SYNTHETIC_ERRNO(EINVAL), "No file descriptors passed, but --fdname= set, refusing.");
bool have_env = arg_ready || arg_stopping || arg_reloading || arg_status || arg_pid > 0 || !fdset_isempty(arg_fds);
bool have_env = arg_ready || arg_stopping || arg_reloading || arg_status || pidref_is_set(&arg_pid) || !fdset_isempty(arg_fds);
size_t n_arg_env;
if (do_exec) {
@@ -326,9 +336,10 @@ static int parse_argv(int argc, char *argv[]) {
}
static int run(int argc, char* argv[]) {
_cleanup_free_ char *status = NULL, *cpid = NULL, *msg = NULL, *monotonic_usec = NULL, *fdn = NULL;
_cleanup_free_ char *status = NULL, *main_pid = NULL, *main_pidfd_id = NULL, *msg = NULL,
*monotonic_usec = NULL, *fdn = NULL;
_cleanup_strv_free_ char **final_env = NULL;
const char *our_env[9];
const char *our_env[10];
size_t i = 0;
int r;
@@ -371,11 +382,22 @@ static int run(int argc, char* argv[]) {
our_env[i++] = status;
}
if (arg_pid > 0) {
if (asprintf(&cpid, "MAINPID="PID_FMT, arg_pid) < 0)
if (pidref_is_set(&arg_pid)) {
if (asprintf(&main_pid, "MAINPID="PID_FMT, arg_pid.pid) < 0)
return log_oom();
our_env[i++] = cpid;
our_env[i++] = main_pid;
r = pidref_acquire_pidfd_id(&arg_pid);
if (r < 0)
log_debug_errno(r, "Unable to acquire pidfd id of new main pid " PID_FMT ", ignoring: %m",
arg_pid.pid);
else {
if (asprintf(&main_pidfd_id, "MAINPIDFDID=%" PRIu64, arg_pid.fd_id) < 0)
return log_oom();
our_env[i++] = main_pidfd_id;
}
}
if (!fdset_isempty(arg_fds)) {
@@ -415,11 +437,11 @@ static int run(int argc, char* argv[]) {
/* If --pid= is explicitly specified, use it as source pid. Otherwise, pretend the message originates
* from our parent, i.e. --pid=auto */
if (arg_pid <= 0)
arg_pid = pid_parent_if_possible();
if (!pidref_is_set(&arg_pid))
(void) pidref_parent_if_applicable(&arg_pid);
if (fdset_isempty(arg_fds))
r = sd_pid_notify(arg_pid, /* unset_environment= */ false, msg);
r = sd_pid_notify(arg_pid.pid, /* unset_environment= */ false, msg);
else {
_cleanup_free_ int *a = NULL;
int k;
@@ -428,7 +450,7 @@ static int run(int argc, char* argv[]) {
if (k < 0)
return log_error_errno(k, "Failed to convert file descriptor set to array: %m");
r = sd_pid_notify_with_fds(arg_pid, /* unset_environment= */ false, msg, a, k);
r = sd_pid_notify_with_fds(arg_pid.pid, /* unset_environment= */ false, msg, a, k);
}
if (r < 0)
@@ -440,7 +462,7 @@ static int run(int argc, char* argv[]) {
arg_fds = fdset_free(arg_fds); /* Close before we execute anything */
if (!arg_no_block) {
r = sd_pid_notify_barrier(arg_pid, /* unset_environment= */ false, 5 * USEC_PER_SEC);
r = sd_pid_notify_barrier(arg_pid.pid, /* unset_environment= */ false, 5 * USEC_PER_SEC);
if (r < 0)
return log_error_errno(r, "Failed to invoke barrier: %m");
if (r == 0)
src/shared/fdset.c
+19 -21
View File
@@ -22,7 +22,7 @@
#define MAKE_SET(s) ((Set*) s)
#define MAKE_FDSET(s) ((FDSet*) s)
FDSet *fdset_new(void) {
FDSet* fdset_new(void) {
return MAKE_FDSET(set_new(NULL));
}
@@ -52,12 +52,20 @@ int fdset_new_array(FDSet **ret, const int fds[], size_t n_fds) {
return 0;
}
void fdset_close(FDSet *s, bool async) {
int fdset_steal_first(FDSet *fds) {
void *p;
while ((p = set_steal_first(MAKE_SET(s)))) {
int fd = PTR_TO_FD(p);
p = set_steal_first(MAKE_SET(fds));
if (!p)
return -ENOENT;
return PTR_TO_FD(p);
}
void fdset_close(FDSet *fds, bool async) {
int fd;
while ((fd = fdset_steal_first(fds)) >= 0) {
/* Valgrind's fd might have ended up in this set here, due to fdset_new_fill(). We'll ignore
* all failures here, so that the EBADFD that valgrind will return us on close() doesn't
* influence us */
@@ -144,7 +152,7 @@ bool fdset_contains(FDSet *s, int fd) {
return false;
}
return !!set_get(MAKE_SET(s), FD_TO_PTR(fd));
return set_contains(MAKE_SET(s), FD_TO_PTR(fd));
}
int fdset_remove(FDSet *s, int fd) {
@@ -230,13 +238,13 @@ int fdset_new_fill(
}
int fdset_cloexec(FDSet *fds, bool b) {
void *p;
int r;
assert(fds);
SET_FOREACH(p, MAKE_SET(fds)) {
r = fd_cloexec(PTR_TO_FD(p), b);
int fd;
FDSET_FOREACH(fd, fds) {
r = fd_cloexec(fd, b);
if (r < 0)
return r;
}
@@ -269,7 +277,6 @@ int fdset_new_listen_fds(FDSet **ret, bool unset) {
int fdset_to_array(FDSet *fds, int **ret) {
unsigned j = 0, m;
void *e;
int *a;
assert(ret);
@@ -286,8 +293,9 @@ int fdset_to_array(FDSet *fds, int **ret) {
if (!a)
return -ENOMEM;
SET_FOREACH(e, MAKE_SET(fds))
a[j++] = PTR_TO_FD(e);
int fd;
FDSET_FOREACH(fd, fds)
a[j++] = fd;
assert(j == m);
@@ -322,13 +330,3 @@ int fdset_iterate(FDSet *s, Iterator *i) {
return PTR_TO_FD(p);
}
int fdset_steal_first(FDSet *fds) {
void *p;
p = set_steal_first(MAKE_SET(fds));
if (!p)
return -ENOENT;
return PTR_TO_FD(p);
}