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authorLennart Poettering <lennart@poettering.net>2015-10-07 23:07:39 +0200
committerLennart Poettering <lennart@poettering.net>2015-10-08 12:55:15 +0200
commita34ceba66fc0e856d8f76f340389a4768b57a365 (patch)
treeb34ee4cf6eda0d1fef3df2235c58252b96958c69 /src/core
parent66cb2fde7b0ab6603775ad13c30c004f5fd88f0c (diff)
core: add support for setting stdin/stdout/stderr for transient services
When starting a transient service, allow setting stdin/stdout/stderr fds for it, by passing them in via the bus. This also simplifies some of the serialization code for units.
Diffstat (limited to 'src/core')
-rw-r--r--src/core/automount.c15
-rw-r--r--src/core/busname.c13
-rw-r--r--src/core/dbus-service.c32
-rw-r--r--src/core/execute.c113
-rw-r--r--src/core/execute.h19
-rw-r--r--src/core/mount.c3
-rw-r--r--src/core/service.c96
-rw-r--r--src/core/service.h4
-rw-r--r--src/core/socket.c3
-rw-r--r--src/core/swap.c3
-rw-r--r--src/core/unit.c65
-rw-r--r--src/core/unit.h8
12 files changed, 278 insertions, 96 deletions
diff --git a/src/core/automount.c b/src/core/automount.c
index 8173a6cbe8..e0535ec201 100644
--- a/src/core/automount.c
+++ b/src/core/automount.c
@@ -774,8 +774,9 @@ static int automount_stop(Unit *u) {
static int automount_serialize(Unit *u, FILE *f, FDSet *fds) {
Automount *a = AUTOMOUNT(u);
- void *p;
Iterator i;
+ void *p;
+ int r;
assert(a);
assert(f);
@@ -790,15 +791,9 @@ static int automount_serialize(Unit *u, FILE *f, FDSet *fds) {
SET_FOREACH(p, a->expire_tokens, i)
unit_serialize_item_format(u, f, "expire-token", "%u", PTR_TO_UINT(p));
- if (a->pipe_fd >= 0) {
- int copy;
-
- copy = fdset_put_dup(fds, a->pipe_fd);
- if (copy < 0)
- return copy;
-
- unit_serialize_item_format(u, f, "pipe-fd", "%i", copy);
- }
+ r = unit_serialize_item_fd(u, f, fds, "pipe-fd", a->pipe_fd);
+ if (r < 0)
+ return r;
return 0;
}
diff --git a/src/core/busname.c b/src/core/busname.c
index ba353ab660..38becfc119 100644
--- a/src/core/busname.c
+++ b/src/core/busname.c
@@ -656,6 +656,7 @@ static int busname_stop(Unit *u) {
static int busname_serialize(Unit *u, FILE *f, FDSet *fds) {
BusName *n = BUSNAME(u);
+ int r;
assert(n);
assert(f);
@@ -667,15 +668,9 @@ static int busname_serialize(Unit *u, FILE *f, FDSet *fds) {
if (n->control_pid > 0)
unit_serialize_item_format(u, f, "control-pid", PID_FMT, n->control_pid);
- if (n->starter_fd >= 0) {
- int copy;
-
- copy = fdset_put_dup(fds, n->starter_fd);
- if (copy < 0)
- return copy;
-
- unit_serialize_item_format(u, f, "starter-fd", "%i", copy);
- }
+ r = unit_serialize_item_fd(u, f, fds, "starter-fd", n->starter_fd);
+ if (r < 0)
+ return r;
return 0;
}
diff --git a/src/core/dbus-service.c b/src/core/dbus-service.c
index 3436342bef..b636f8ba6a 100644
--- a/src/core/dbus-service.c
+++ b/src/core/dbus-service.c
@@ -19,6 +19,7 @@
along with systemd; If not, see <http://www.gnu.org/licenses/>.
***/
+#include "async.h"
#include "strv.h"
#include "path-util.h"
#include "unit.h"
@@ -120,6 +121,37 @@ static int bus_service_set_transient_property(
return 1;
+ } else if (STR_IN_SET(name,
+ "StandardInputFileDescriptor",
+ "StandardOutputFileDescriptor",
+ "StandardErrorFileDescriptor")) {
+ int fd;
+
+ r = sd_bus_message_read(message, "h", &fd);
+ if (r < 0)
+ return r;
+
+ if (mode != UNIT_CHECK) {
+ int copy;
+
+ copy = fcntl(fd, F_DUPFD_CLOEXEC, 3);
+ if (copy < 0)
+ return -errno;
+
+ if (streq(name, "StandardInputFileDescriptor")) {
+ asynchronous_close(s->stdin_fd);
+ s->stdin_fd = copy;
+ } else if (streq(name, "StandardOutputFileDescriptor")) {
+ asynchronous_close(s->stdout_fd);
+ s->stdout_fd = copy;
+ } else {
+ asynchronous_close(s->stderr_fd);
+ s->stderr_fd = copy;
+ }
+ }
+
+ return 1;
+
} else if (streq(name, "ExecStart")) {
unsigned n = 0;
diff --git a/src/core/execute.c b/src/core/execute.c
index f5baad05f3..80ad87d4e4 100644
--- a/src/core/execute.c
+++ b/src/core/execute.c
@@ -359,12 +359,28 @@ static int fixup_output(ExecOutput std_output, int socket_fd) {
return std_output;
}
-static int setup_input(const ExecContext *context, int socket_fd, bool apply_tty_stdin) {
+static int setup_input(
+ const ExecContext *context,
+ const ExecParameters *params,
+ int socket_fd) {
+
ExecInput i;
assert(context);
+ assert(params);
+
+ if (params->stdin_fd >= 0) {
+ if (dup2(params->stdin_fd, STDIN_FILENO) < 0)
+ return -errno;
+
+ /* Try to make this the controlling tty, if it is a tty, and reset it */
+ (void) ioctl(STDIN_FILENO, TIOCSCTTY, context->std_input == EXEC_INPUT_TTY_FORCE);
+ (void) reset_terminal_fd(STDIN_FILENO, true);
+
+ return STDIN_FILENO;
+ }
- i = fixup_input(context->std_input, socket_fd, apply_tty_stdin);
+ i = fixup_input(context->std_input, socket_fd, params->apply_tty_stdin);
switch (i) {
@@ -401,16 +417,40 @@ static int setup_input(const ExecContext *context, int socket_fd, bool apply_tty
}
}
-static int setup_output(Unit *unit, const ExecContext *context, int fileno, int socket_fd, const char *ident, bool apply_tty_stdin, uid_t uid, gid_t gid) {
+static int setup_output(
+ Unit *unit,
+ const ExecContext *context,
+ const ExecParameters *params,
+ int fileno,
+ int socket_fd,
+ const char *ident,
+ uid_t uid, gid_t gid) {
+
ExecOutput o;
ExecInput i;
int r;
assert(unit);
assert(context);
+ assert(params);
assert(ident);
- i = fixup_input(context->std_input, socket_fd, apply_tty_stdin);
+ if (fileno == STDOUT_FILENO && params->stdout_fd >= 0) {
+
+ if (dup2(params->stdout_fd, STDOUT_FILENO) < 0)
+ return -errno;
+
+ return STDOUT_FILENO;
+ }
+
+ if (fileno == STDERR_FILENO && params->stderr_fd >= 0) {
+ if (dup2(params->stderr_fd, STDERR_FILENO) < 0)
+ return -errno;
+
+ return STDERR_FILENO;
+ }
+
+ i = fixup_input(context->std_input, socket_fd, params->apply_tty_stdin);
o = fixup_output(context->std_output, socket_fd);
if (fileno == STDERR_FILENO) {
@@ -1324,6 +1364,44 @@ static bool exec_needs_mount_namespace(
return false;
}
+static int close_remaining_fds(
+ const ExecParameters *params,
+ ExecRuntime *runtime,
+ int socket_fd,
+ int *fds, unsigned n_fds) {
+
+ unsigned n_dont_close = 0;
+ int dont_close[n_fds + 7];
+
+ assert(params);
+
+ 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;
+
+ if (socket_fd >= 0)
+ dont_close[n_dont_close++] = socket_fd;
+ if (n_fds > 0) {
+ memcpy(dont_close + n_dont_close, fds, sizeof(int) * n_fds);
+ n_dont_close += n_fds;
+ }
+
+ if (params->bus_endpoint_fd >= 0)
+ dont_close[n_dont_close++] = params->bus_endpoint_fd;
+
+ if (runtime) {
+ if (runtime->netns_storage_socket[0] >= 0)
+ dont_close[n_dont_close++] = runtime->netns_storage_socket[0];
+ if (runtime->netns_storage_socket[1] >= 0)
+ dont_close[n_dont_close++] = runtime->netns_storage_socket[1];
+ }
+
+ return close_all_fds(dont_close, n_dont_close);
+}
+
static int exec_child(
Unit *unit,
ExecCommand *command,
@@ -1339,8 +1417,6 @@ static int exec_child(
_cleanup_strv_free_ char **our_env = NULL, **pam_env = NULL, **final_env = NULL, **final_argv = NULL;
_cleanup_free_ char *mac_selinux_context_net = NULL;
const char *username = NULL, *home = NULL, *shell = NULL, *wd;
- unsigned n_dont_close = 0;
- int dont_close[n_fds + 4];
uid_t uid = UID_INVALID;
gid_t gid = GID_INVALID;
int i, r;
@@ -1380,22 +1456,7 @@ static int exec_child(
log_forget_fds();
- if (socket_fd >= 0)
- dont_close[n_dont_close++] = socket_fd;
- if (n_fds > 0) {
- memcpy(dont_close + n_dont_close, fds, sizeof(int) * n_fds);
- n_dont_close += n_fds;
- }
- if (params->bus_endpoint_fd >= 0)
- dont_close[n_dont_close++] = params->bus_endpoint_fd;
- if (runtime) {
- if (runtime->netns_storage_socket[0] >= 0)
- dont_close[n_dont_close++] = runtime->netns_storage_socket[0];
- if (runtime->netns_storage_socket[1] >= 0)
- dont_close[n_dont_close++] = runtime->netns_storage_socket[1];
- }
-
- r = close_all_fds(dont_close, n_dont_close);
+ r = close_remaining_fds(params, runtime, socket_fd, fds, n_fds);
if (r < 0) {
*exit_status = EXIT_FDS;
return r;
@@ -1451,21 +1512,21 @@ static int exec_child(
/* If a socket is connected to STDIN/STDOUT/STDERR, we
* must sure to drop O_NONBLOCK */
if (socket_fd >= 0)
- fd_nonblock(socket_fd, false);
+ (void) fd_nonblock(socket_fd, false);
- r = setup_input(context, socket_fd, params->apply_tty_stdin);
+ r = setup_input(context, params, socket_fd);
if (r < 0) {
*exit_status = EXIT_STDIN;
return r;
}
- r = setup_output(unit, context, STDOUT_FILENO, socket_fd, basename(command->path), params->apply_tty_stdin, uid, gid);
+ r = setup_output(unit, context, params, STDOUT_FILENO, socket_fd, basename(command->path), uid, gid);
if (r < 0) {
*exit_status = EXIT_STDOUT;
return r;
}
- r = setup_output(unit, context, STDERR_FILENO, socket_fd, basename(command->path), params->apply_tty_stdin, uid, gid);
+ r = setup_output(unit, context, params, STDERR_FILENO, socket_fd, basename(command->path), uid, gid);
if (r < 0) {
*exit_status = EXIT_STDERR;
return r;
diff --git a/src/core/execute.h b/src/core/execute.h
index f1c37116fd..f8995a4203 100644
--- a/src/core/execute.h
+++ b/src/core/execute.h
@@ -208,23 +208,22 @@ struct ExecContext {
struct ExecParameters {
char **argv;
+ char **environment;
int *fds;
char **fd_names;
unsigned n_fds;
- char **environment;
-
- bool apply_permissions;
- bool apply_chroot;
- bool apply_tty_stdin;
+ bool apply_permissions:1;
+ bool apply_chroot:1;
+ bool apply_tty_stdin:1;
- bool confirm_spawn;
- bool selinux_context_net;
+ bool confirm_spawn:1;
+ bool selinux_context_net:1;
+ bool cgroup_delegate:1;
CGroupMask cgroup_supported;
const char *cgroup_path;
- bool cgroup_delegate;
const char *runtime_prefix;
@@ -234,6 +233,10 @@ struct ExecParameters {
char *bus_endpoint_path;
int bus_endpoint_fd;
+
+ int stdin_fd;
+ int stdout_fd;
+ int stderr_fd;
};
int exec_spawn(Unit *unit,
diff --git a/src/core/mount.c b/src/core/mount.c
index a74f116657..8611129453 100644
--- a/src/core/mount.c
+++ b/src/core/mount.c
@@ -694,6 +694,9 @@ static int mount_spawn(Mount *m, ExecCommand *c, pid_t *_pid) {
.apply_chroot = true,
.apply_tty_stdin = true,
.bus_endpoint_fd = -1,
+ .stdin_fd = -1,
+ .stdout_fd = -1,
+ .stderr_fd = -1,
};
assert(m);
diff --git a/src/core/service.c b/src/core/service.c
index ce3b81398d..1e4f707bf4 100644
--- a/src/core/service.c
+++ b/src/core/service.c
@@ -108,6 +108,7 @@ static void service_init(Unit *u) {
s->type = _SERVICE_TYPE_INVALID;
s->socket_fd = -1;
s->bus_endpoint_fd = -1;
+ s->stdin_fd = s->stdout_fd = s->stderr_fd = -1;
s->guess_main_pid = true;
RATELIMIT_INIT(s->start_limit, u->manager->default_start_limit_interval, u->manager->default_start_limit_burst);
@@ -271,11 +272,15 @@ static void service_release_resources(Unit *u) {
assert(s);
- if (!s->fd_store)
+ if (!s->fd_store && s->stdin_fd < 0 && s->stdout_fd < 0 && s->stderr_fd < 0)
return;
log_unit_debug(u, "Releasing all resources.");
+ s->stdin_fd = safe_close(s->stdin_fd);
+ s->stdout_fd = safe_close(s->stdout_fd);
+ s->stderr_fd = safe_close(s->stderr_fd);
+
while (s->fd_store)
service_fd_store_unlink(s->fd_store);
@@ -1090,11 +1095,13 @@ static int service_spawn(
pid_t pid;
ExecParameters exec_params = {
- .apply_permissions = apply_permissions,
- .apply_chroot = apply_chroot,
- .apply_tty_stdin = apply_tty_stdin,
- .bus_endpoint_fd = -1,
- .selinux_context_net = s->socket_fd_selinux_context_net
+ .apply_permissions = apply_permissions,
+ .apply_chroot = apply_chroot,
+ .apply_tty_stdin = apply_tty_stdin,
+ .bus_endpoint_fd = -1,
+ .stdin_fd = -1,
+ .stdout_fd = -1,
+ .stderr_fd = -1,
};
int r;
@@ -1236,8 +1243,12 @@ static int service_spawn(
exec_params.runtime_prefix = manager_get_runtime_prefix(UNIT(s)->manager);
exec_params.watchdog_usec = s->watchdog_usec;
exec_params.bus_endpoint_path = bus_endpoint_path;
+ exec_params.selinux_context_net = s->socket_fd_selinux_context_net;
if (s->type == SERVICE_IDLE)
exec_params.idle_pipe = UNIT(s)->manager->idle_pipe;
+ exec_params.stdin_fd = s->stdin_fd;
+ exec_params.stdout_fd = s->stdout_fd;
+ exec_params.stderr_fd = s->stderr_fd;
r = exec_spawn(UNIT(s),
c,
@@ -2038,6 +2049,7 @@ _pure_ static bool service_can_reload(Unit *u) {
static int service_serialize(Unit *u, FILE *f, FDSet *fds) {
Service *s = SERVICE(u);
ServiceFDStore *fs;
+ int r;
assert(u);
assert(f);
@@ -2056,12 +2068,9 @@ static int service_serialize(Unit *u, FILE *f, FDSet *fds) {
unit_serialize_item(u, f, "main-pid-known", yes_no(s->main_pid_known));
unit_serialize_item(u, f, "bus-name-good", yes_no(s->bus_name_good));
- if (s->status_text) {
- _cleanup_free_ char *c = NULL;
-
- c = cescape(s->status_text);
- unit_serialize_item(u, f, "status-text", strempty(c));
- }
+ r = unit_serialize_item_escaped(u, f, "status-text", s->status_text);
+ if (r < 0)
+ return r;
/* FIXME: There's a minor uncleanliness here: if there are
* multiple commands attached here, we will start from the
@@ -2069,25 +2078,22 @@ static int service_serialize(Unit *u, FILE *f, FDSet *fds) {
if (s->control_command_id >= 0)
unit_serialize_item(u, f, "control-command", service_exec_command_to_string(s->control_command_id));
- if (s->socket_fd >= 0) {
- int copy;
-
- copy = fdset_put_dup(fds, s->socket_fd);
- if (copy < 0)
- return copy;
-
- unit_serialize_item_format(u, f, "socket-fd", "%i", copy);
- }
-
- if (s->bus_endpoint_fd >= 0) {
- int copy;
-
- copy = fdset_put_dup(fds, s->bus_endpoint_fd);
- if (copy < 0)
- return copy;
+ r = unit_serialize_item_fd(u, f, fds, "stdin-fd", s->stdin_fd);
+ if (r < 0)
+ return r;
+ r = unit_serialize_item_fd(u, f, fds, "stdout-fd", s->stdout_fd);
+ if (r < 0)
+ return r;
+ r = unit_serialize_item_fd(u, f, fds, "stderr-fd", s->stderr_fd);
+ if (r < 0)
+ return r;
- unit_serialize_item_format(u, f, "endpoint-fd", "%i", copy);
- }
+ r = unit_serialize_item_fd(u, f, fds, "socket-fd", s->socket_fd);
+ if (r < 0)
+ return r;
+ r = unit_serialize_item_fd(u, f, fds, "endpoint-fd", s->bus_endpoint_fd);
+ if (r < 0)
+ return r;
LIST_FOREACH(fd_store, fs, s->fd_store) {
_cleanup_free_ char *c = NULL;
@@ -2116,8 +2122,7 @@ static int service_serialize(Unit *u, FILE *f, FDSet *fds) {
if (dual_timestamp_is_set(&s->watchdog_timestamp))
dual_timestamp_serialize(f, "watchdog-timestamp", &s->watchdog_timestamp);
- if (s->forbid_restart)
- unit_serialize_item(u, f, "forbid-restart", yes_no(s->forbid_restart));
+ unit_serialize_item(u, f, "forbid-restart", yes_no(s->forbid_restart));
return 0;
}
@@ -2288,6 +2293,33 @@ static int service_deserialize_item(Unit *u, const char *key, const char *value,
log_unit_debug(u, "Failed to parse forbid-restart value: %s", value);
else
s->forbid_restart = b;
+ } else if (streq(key, "stdin-fd")) {
+ int fd;
+
+ if (safe_atoi(value, &fd) < 0 || fd < 0 || !fdset_contains(fds, fd))
+ log_unit_debug(u, "Failed to parse stdin-fd value: %s", value);
+ else {
+ asynchronous_close(s->stdin_fd);
+ s->stdin_fd = fdset_remove(fds, fd);
+ }
+ } else if (streq(key, "stdout-fd")) {
+ int fd;
+
+ if (safe_atoi(value, &fd) < 0 || fd < 0 || !fdset_contains(fds, fd))
+ log_unit_debug(u, "Failed to parse stdout-fd value: %s", value);
+ else {
+ asynchronous_close(s->stdout_fd);
+ s->stdout_fd = fdset_remove(fds, fd);
+ }
+ } else if (streq(key, "stderr-fd")) {
+ int fd;
+
+ if (safe_atoi(value, &fd) < 0 || fd < 0 || !fdset_contains(fds, fd))
+ log_unit_debug(u, "Failed to parse stderr-fd value: %s", value);
+ else {
+ asynchronous_close(s->stderr_fd);
+ s->stderr_fd = fdset_remove(fds, fd);
+ }
} else
log_unit_debug(u, "Unknown serialization key: %s", key);
diff --git a/src/core/service.h b/src/core/service.h
index 61bb44fbcf..e765668247 100644
--- a/src/core/service.h
+++ b/src/core/service.h
@@ -195,6 +195,10 @@ struct Service {
char *usb_function_descriptors;
char *usb_function_strings;
+
+ int stdin_fd;
+ int stdout_fd;
+ int stderr_fd;
};
extern const UnitVTable service_vtable;
diff --git a/src/core/socket.c b/src/core/socket.c
index 6300b20f3e..e42ed62ef1 100644
--- a/src/core/socket.c
+++ b/src/core/socket.c
@@ -1505,6 +1505,9 @@ static int socket_spawn(Socket *s, ExecCommand *c, pid_t *_pid) {
.apply_chroot = true,
.apply_tty_stdin = true,
.bus_endpoint_fd = -1,
+ .stdin_fd = -1,
+ .stdout_fd = -1,
+ .stderr_fd = -1,
};
assert(s);
diff --git a/src/core/swap.c b/src/core/swap.c
index 1f94d32318..f42d151075 100644
--- a/src/core/swap.c
+++ b/src/core/swap.c
@@ -597,6 +597,9 @@ static int swap_spawn(Swap *s, ExecCommand *c, pid_t *_pid) {
.apply_chroot = true,
.apply_tty_stdin = true,
.bus_endpoint_fd = -1,
+ .stdin_fd = -1,
+ .stdout_fd = -1,
+ .stderr_fd = -1,
};
assert(s);
diff --git a/src/core/unit.c b/src/core/unit.c
index 33c0317ce0..423caa9562 100644
--- a/src/core/unit.c
+++ b/src/core/unit.c
@@ -2624,6 +2624,62 @@ int unit_serialize(Unit *u, FILE *f, FDSet *fds, bool serialize_jobs) {
return 0;
}
+int unit_serialize_item(Unit *u, FILE *f, const char *key, const char *value) {
+ assert(u);
+ assert(f);
+ assert(key);
+
+ if (!value)
+ return 0;
+
+ fputs(key, f);
+ fputc('=', f);
+ fputs(value, f);
+ fputc('\n', f);
+
+ return 1;
+}
+
+int unit_serialize_item_escaped(Unit *u, FILE *f, const char *key, const char *value) {
+ _cleanup_free_ char *c = NULL;
+
+ assert(u);
+ assert(f);
+ assert(key);
+
+ if (!value)
+ return 0;
+
+ c = cescape(value);
+ if (!c)
+ return -ENOMEM;
+
+ fputs(key, f);
+ fputc('=', f);
+ fputs(c, f);
+ fputc('\n', f);
+
+ return 1;
+}
+
+int unit_serialize_item_fd(Unit *u, FILE *f, FDSet *fds, const char *key, int fd) {
+ int copy;
+
+ assert(u);
+ assert(f);
+ assert(key);
+
+ if (fd < 0)
+ return 0;
+
+ copy = fdset_put_dup(fds, fd);
+ if (copy < 0)
+ return copy;
+
+ fprintf(f, "%s=%i\n", key, copy);
+ return 1;
+}
+
void unit_serialize_item_format(Unit *u, FILE *f, const char *key, const char *format, ...) {
va_list ap;
@@ -2642,15 +2698,6 @@ void unit_serialize_item_format(Unit *u, FILE *f, const char *key, const char *f
fputc('\n', f);
}
-void unit_serialize_item(Unit *u, FILE *f, const char *key, const char *value) {
- assert(u);
- assert(f);
- assert(key);
- assert(value);
-
- fprintf(f, "%s=%s\n", key, value);
-}
-
int unit_deserialize(Unit *u, FILE *f, FDSet *fds) {
ExecRuntime **rt = NULL;
size_t offset;
diff --git a/src/core/unit.h b/src/core/unit.h
index e8d5f86eca..a4a1b011fc 100644
--- a/src/core/unit.h
+++ b/src/core/unit.h
@@ -533,11 +533,15 @@ char *unit_dbus_path(Unit *u);
int unit_load_related_unit(Unit *u, const char *type, Unit **_found);
bool unit_can_serialize(Unit *u) _pure_;
+
int unit_serialize(Unit *u, FILE *f, FDSet *fds, bool serialize_jobs);
-void unit_serialize_item_format(Unit *u, FILE *f, const char *key, const char *value, ...) _printf_(4,5);
-void unit_serialize_item(Unit *u, FILE *f, const char *key, const char *value);
int unit_deserialize(Unit *u, FILE *f, FDSet *fds);
+int unit_serialize_item(Unit *u, FILE *f, const char *key, const char *value);
+int unit_serialize_item_escaped(Unit *u, FILE *f, const char *key, const char *value);
+int unit_serialize_item_fd(Unit *u, FILE *f, FDSet *fds, const char *key, int fd);
+void unit_serialize_item_format(Unit *u, FILE *f, const char *key, const char *value, ...) _printf_(4,5);
+
int unit_add_node_link(Unit *u, const char *what, bool wants);
int unit_coldplug(Unit *u);