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core: only apply NonBlocking= to fds passed via socket activation

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Make sure to only apply the O_NONBLOCK flag to the fds passed via socket
activation.

Previously the flag was also applied to the fds which came from the fd store
but this was incorrect since services, after being restarted, expect that these
passed fds have their flags unchanged and can be reused as before.

The documentation was a bit unclear about this so clarify it.
This commit is contained in:
Franck Bui 2017-05-12 11:32:53 +02:00
parent fbcc7f4168
commit 9b1419111a
4 changed files with 33 additions and 20 deletions
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17
man/systemd.service.xml
View File

@ -782,15 +782,14 @@
<varlistentry>
<term><varname>NonBlocking=</varname></term>
<listitem><para>Set the <constant>O_NONBLOCK</constant> flag
for all file descriptors passed via socket-based activation.
If true, all file descriptors >= 3 (i.e. all except stdin,
stdout, and stderr) will have the
<constant>O_NONBLOCK</constant> flag set and hence are in
non-blocking mode. This option is only useful in conjunction
with a socket unit, as described in
<citerefentry><refentrytitle>systemd.socket</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
Defaults to false.</para></listitem>
<listitem><para>Set the <constant>O_NONBLOCK</constant> flag for all file descriptors passed via socket-based
activation. If true, all file descriptors >= 3 (i.e. all except stdin, stdout, stderr), excluding those passed
in via the file descriptor storage logic (see <varname>FileDescriptorStoreMax=</varname> for details), will
have the <constant>O_NONBLOCK</constant> flag set and hence are in non-blocking mode. This option is only
useful in conjunction with a socket unit, as described in
<citerefentry><refentrytitle>systemd.socket</refentrytitle><manvolnum>5</manvolnum></citerefentry> and has no
effect on file descriptors which were previously saved in the file-descriptor store for example. Defaults to
false.</para></listitem>
</varlistentry>
<varlistentry>

21
src/core/execute.c
View File

@ -157,7 +157,7 @@ static int shift_fds(int fds[], unsigned n_fds) {
return 0;
}
static int flags_fds(const int fds[], unsigned n_fds, bool nonblock) {
static int flags_fds(const int fds[], unsigned n_fds, unsigned n_socket_fds, bool nonblock) {
unsigned i;
int r;
@ -166,13 +166,16 @@ static int flags_fds(const int fds[], unsigned n_fds, bool nonblock) {
assert(fds);
/* Drops/Sets O_NONBLOCK and FD_CLOEXEC from the file flags */
/* Drops/Sets O_NONBLOCK and FD_CLOEXEC from the file flags.
* O_NONBLOCK only applies to socket activation though. */
for (i = 0; i < n_fds; i++) {
r = fd_nonblock(fds[i], nonblock);
if (r < 0)
return r;
if (i < n_socket_fds) {
r = fd_nonblock(fds[i], nonblock);
if (r < 0)
return r;
}
/* We unconditionally drop FD_CLOEXEC from the fds,
* since after all we want to pass these fds to our
@ -2242,6 +2245,7 @@ static int exec_child(
int socket_fd,
int named_iofds[3],
int *fds, unsigned n_fds,
unsigned n_socket_fds,
char **files_env,
int user_lookup_fd,
int *exit_status,
@ -2669,7 +2673,7 @@ static int exec_child(
if (r >= 0)
r = shift_fds(fds, n_fds);
if (r >= 0)
r = flags_fds(fds, n_fds, context->non_blocking);
r = flags_fds(fds, n_fds, n_socket_fds, context->non_blocking);
if (r < 0) {
*exit_status = EXIT_FDS;
return r;
@ -2909,7 +2913,8 @@ int exec_spawn(Unit *unit,
pid_t *ret) {
_cleanup_strv_free_ char **files_env = NULL;
int *fds = NULL; unsigned n_fds = 0;
int *fds = NULL;
unsigned n_fds = 0, n_socket_fds = 0;
_cleanup_free_ char *line = NULL;
int socket_fd, r;
int named_iofds[3] = { -1, -1, -1 };
@ -2942,6 +2947,7 @@ int exec_spawn(Unit *unit,
socket_fd = -1;
fds = params->fds;
n_fds = params->n_fds;
n_socket_fds = params->n_socket_fds;
}
r = exec_context_named_iofds(unit, context, params, named_iofds);
@ -2980,6 +2986,7 @@ int exec_spawn(Unit *unit,
socket_fd,
named_iofds,
fds, n_fds,
n_socket_fds,
files_env,
unit->manager->user_lookup_fds[1],
&exit_status,

1
src/core/execute.h
View File

@ -247,6 +247,7 @@ struct ExecParameters {
int *fds;
char **fd_names;
unsigned n_fds;
unsigned n_socket_fds;
ExecFlags flags;
bool selinux_context_net:1;

14
src/core/service.c
View File

@ -1068,14 +1068,16 @@ static int service_coldplug(Unit *u) {
return 0;
}
static int service_collect_fds(Service *s, int **fds, char ***fd_names) {
static int service_collect_fds(Service *s, int **fds, char ***fd_names, unsigned *n_socket_fds) {
_cleanup_strv_free_ char **rfd_names = NULL;
_cleanup_free_ int *rfds = NULL;
int rn_fds = 0, r;
unsigned rn_socket_fds = 0;
int rn_fds = 0, r;
assert(s);
assert(fds);
assert(fd_names);
assert(n_socket_fds);
if (s->socket_fd >= 0) {
@ -1138,6 +1140,8 @@ static int service_collect_fds(Service *s, int **fds, char ***fd_names) {
}
}
rn_socket_fds = rn_fds;
if (s->n_fd_store > 0) {
ServiceFDStore *fs;
char **nl;
@ -1169,6 +1173,7 @@ static int service_collect_fds(Service *s, int **fds, char ***fd_names) {
*fds = rfds;
*fd_names = rfd_names;
*n_socket_fds = rn_socket_fds;
rfds = NULL;
rfd_names = NULL;
@ -1204,7 +1209,7 @@ static int service_spawn(
_cleanup_strv_free_ char **final_env = NULL, **our_env = NULL, **fd_names = NULL;
_cleanup_free_ int *fds = NULL;
unsigned n_fds = 0, n_env = 0;
unsigned n_fds = 0, n_socket_fds = 0, n_env = 0;
const char *path;
pid_t pid;
@ -1248,7 +1253,7 @@ static int service_spawn(
s->exec_context.std_output == EXEC_OUTPUT_SOCKET ||
s->exec_context.std_error == EXEC_OUTPUT_SOCKET) {
r = service_collect_fds(s, &fds, &fd_names);
r = service_collect_fds(s, &fds, &fd_names, &n_socket_fds);
if (r < 0)
return r;
@ -1348,6 +1353,7 @@ static int service_spawn(
exec_params.fds = fds;
exec_params.fd_names = fd_names;
exec_params.n_fds = n_fds;
exec_params.n_socket_fds = n_socket_fds;
exec_params.confirm_spawn = manager_get_confirm_spawn(UNIT(s)->manager);
exec_params.cgroup_supported = UNIT(s)->manager->cgroup_supported;
exec_params.cgroup_path = path;