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run: add new --pipe option for including "systemd-run" commands in shell pipelines

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In this mode, we'll directly connect stdin/stdout/stderr of the invoked
service with whatever systemd-run itself is invoked on. This allows
inclusion of "systemd-run" commands in shell pipelines, as unlike
"--pty" this means EOF of stdin/stdout/stderr are propagated
independently.

If --pty and --pipe are combined systemd-run will automatically pick the
right choice for the context it is invoked in, i.e. --pty when invoked
on a TTY, and --pipe otherwise.
This commit is contained in:
Lennart Poettering 2017-09-08 15:38:40 +02:00
parent c13ee7cc8b
commit 5dca7739e8
3 changed files with 83 additions and 25 deletions
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3
TODO
View File

@ -27,9 +27,6 @@ Features:
* dissect: when we discover squashfs, don't claim we had a "writable" partition
in systemd-dissect
* systemd-run should have a way how to connect a pair of pipes to
stdout/stderr/stdin of the invoked service
* set LockPersonality= on all our services
* Add AddUser= setting to unit files, similar to DynamicUser=1 which however

25
man/systemd-run.xml
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@ -219,14 +219,31 @@
<term><option>--pty</option></term>
<term><option>-t</option></term>
<listitem><para>When invoking the command, the transient service connects its standard input and output to the
terminal <command>systemd-run</command> is invoked on, via a pseudo TTY device. This allows running binaries
that expect interactive user input as services, such as interactive command shells.</para>
<listitem><para>When invoking the command, the transient service connects its standard input, output and error
to the terminal <command>systemd-run</command> is invoked on, via a pseudo TTY device. This allows running
binaries that expect interactive user input/output as services, such as interactive command shells.</para>
<para>Note that
<citerefentry><refentrytitle>machinectl</refentrytitle><manvolnum>1</manvolnum></citerefentry>'s
<command>shell</command> command is usually a better alternative for requesting a new, interactive login
session on the local host or a local container.</para></listitem>
session on the local host or a local container.</para>
<para>See below for details on how this switch combines with <option>--pipe</option>.</para></listitem>
</varlistentry>
<varlistentry>
<term><option>--pipe</option></term>
<term><option>-P</option></term>
<listitem><para>If specified, standard input, output, and error of the transient service are inherited from the
<command>systemd-run</command> command itself. Use this option in order to use <command>systemd-run</command>
within shell pipelines. Note that this mode is not suitable for interactive command shells and similar, as the
service process will not be made TTY controller when invoked on a terminal. Use <option>--pty</option> instead
in that case.</para>
<para>When both <option>--pipe</option> and <option>--pty</option> are used in combination the more appropriate
option is automatically determined and used. Specifically, when invoked with standard input, output and error
connected to a TTY <option>--pty</option> is used, and otherwise <option>--pipe</option>.</para></listitem>
</varlistentry>
<varlistentry>

80
src/run/run.c
View File

@ -61,7 +61,12 @@ static int arg_nice = 0;
static bool arg_nice_set = false;
static char **arg_environment = NULL;
static char **arg_property = NULL;
static bool arg_pty = false;
static enum {
ARG_STDIO_NONE, /* The default, as it is for normal services, stdin connected to /dev/null, and stdout+stderr to the journal */
ARG_STDIO_PTY, /* Interactive behaviour, requested by --pty: we allocate a pty and connect it to the TTY we are invoked from */
ARG_STDIO_DIRECT, /* Directly pass our stdin/stdout/stderr to the activated service, useful for usage in shell pipelines, requested by --pipe */
ARG_STDIO_AUTO, /* If --pipe and --pty are used together we use --pty when invoked on a TTY, and --pipe otherwise */
} arg_stdio = ARG_STDIO_NONE;
static usec_t arg_on_active = 0;
static usec_t arg_on_boot = 0;
static usec_t arg_on_startup = 0;
@ -106,7 +111,9 @@ static void help(void) {
" --gid=GROUP Run as system group\n"
" --nice=NICE Nice level\n"
" -E --setenv=NAME=VALUE Set environment\n"
" -t --pty Run service on pseudo tty\n"
" -t --pty Run service on pseudo TTY as STDIN/STDOUT/\n"
" STDERR\n"
" -P --pipe Pass STDIN/STDOUT/STDERR directly to service\n"
" -q --quiet Suppress information messages during runtime\n\n"
"Timer options:\n"
" --on-active=SECONDS Run after SECONDS delay\n"
@ -170,8 +177,9 @@ static int parse_argv(int argc, char *argv[]) {
{ "nice", required_argument, NULL, ARG_NICE },
{ "setenv", required_argument, NULL, 'E' },
{ "property", required_argument, NULL, 'p' },
{ "tty", no_argument, NULL, 't' }, /* deprecated */
{ "tty", no_argument, NULL, 't' }, /* deprecated alias */
{ "pty", no_argument, NULL, 't' },
{ "pipe", no_argument, NULL, 'P' },
{ "quiet", no_argument, NULL, 'q' },
{ "on-active", required_argument, NULL, ARG_ON_ACTIVE },
{ "on-boot", required_argument, NULL, ARG_ON_BOOT },
@ -190,7 +198,7 @@ static int parse_argv(int argc, char *argv[]) {
assert(argc >= 0);
assert(argv);
while ((c = getopt_long(argc, argv, "+hrH:M:E:p:tq", options, NULL)) >= 0)
while ((c = getopt_long(argc, argv, "+hrH:M:E:p:tPq", options, NULL)) >= 0)
switch (c) {
@ -279,8 +287,18 @@ static int parse_argv(int argc, char *argv[]) {
break;
case 't':
arg_pty = true;
case 't': /* --pty */
if (IN_SET(arg_stdio, ARG_STDIO_DIRECT, ARG_STDIO_AUTO)) /* if --pipe is already used, upgrade to auto mode */
arg_stdio = ARG_STDIO_AUTO;
else
arg_stdio = ARG_STDIO_PTY;
break;
case 'P': /* --pipe */
if (IN_SET(arg_stdio, ARG_STDIO_PTY, ARG_STDIO_AUTO)) /* If --pty is already used, upgrade to auto mode */
arg_stdio = ARG_STDIO_AUTO;
else
arg_stdio = ARG_STDIO_DIRECT;
break;
case 'q':
@ -373,6 +391,16 @@ static int parse_argv(int argc, char *argv[]) {
assert_not_reached("Unhandled option");
}
if (arg_stdio == ARG_STDIO_AUTO) {
/* If we both --pty and --pipe are specified we'll automatically pick --pty if we are connected fully
* to a TTY and pick direct fd passing otherwise. This way, we automatically adapt to usage in a shell
* pipeline, but we are neatly interactive with tty-level isolation otherwise. */
arg_stdio = isatty(STDIN_FILENO) && isatty(STDOUT_FILENO) && isatty(STDERR_FILENO) ?
ARG_STDIO_PTY :
ARG_STDIO_DIRECT;
}
if ((optind >= argc) && (!arg_unit || !with_timer())) {
log_error("Command line to execute required.");
return -EINVAL;
@ -393,18 +421,18 @@ static int parse_argv(int argc, char *argv[]) {
return -EINVAL;
}
if (arg_pty && (with_timer() || arg_scope)) {
log_error("--pty is not compatible in timer or --scope mode.");
if (arg_stdio != ARG_STDIO_NONE && (with_timer() || arg_scope)) {
log_error("--pty/--pipe is not compatible in timer or --scope mode.");
return -EINVAL;
}
if (arg_pty && arg_transport == BUS_TRANSPORT_REMOTE) {
log_error("--pty is only supported when connecting to the local system or containers.");
if (arg_stdio != ARG_STDIO_NONE && arg_transport == BUS_TRANSPORT_REMOTE) {
log_error("--pty/--pipe is only supported when connecting to the local system or containers.");
return -EINVAL;
}
if (arg_pty && arg_no_block) {
log_error("--pty is not compatible with --no-block.");
if (arg_stdio != ARG_STDIO_NONE && arg_no_block) {
log_error("--pty/--pipe is not compatible with --no-block.");
return -EINVAL;
}
@ -481,6 +509,7 @@ static int transient_kill_set_properties(sd_bus_message *m) {
}
static int transient_service_set_properties(sd_bus_message *m, char **argv, const char *pty_path) {
bool send_term = false;
int r;
assert(m);
@ -497,7 +526,7 @@ static int transient_service_set_properties(sd_bus_message *m, char **argv, cons
if (r < 0)
return r;
if (arg_wait || arg_pty) {
if (arg_wait || arg_stdio != ARG_STDIO_NONE) {
r = sd_bus_message_append(m, "(sv)", "AddRef", "b", 1);
if (r < 0)
return r;
@ -534,8 +563,6 @@ static int transient_service_set_properties(sd_bus_message *m, char **argv, cons
}
if (pty_path) {
const char *e;
r = sd_bus_message_append(m,
"(sv)(sv)(sv)(sv)",
"StandardInput", "s", "tty",
@ -545,6 +572,23 @@ static int transient_service_set_properties(sd_bus_message *m, char **argv, cons
if (r < 0)
return r;
send_term = true;
} else if (arg_stdio == ARG_STDIO_DIRECT) {
r = sd_bus_message_append(m,
"(sv)(sv)(sv)",
"StandardInputFileDescriptor", "h", STDIN_FILENO,
"StandardOutputFileDescriptor", "h", STDOUT_FILENO,
"StandardErrorFileDescriptor", "h", STDERR_FILENO);
if (r < 0)
return r;
send_term = isatty(STDIN_FILENO) || isatty(STDOUT_FILENO) || isatty(STDERR_FILENO);
}
if (send_term) {
const char *e;
e = getenv("TERM");
if (e) {
char *n;
@ -875,7 +919,7 @@ static int start_transient_service(
assert(argv);
assert(retval);
if (arg_pty) {
if (arg_stdio == ARG_STDIO_PTY) {
if (arg_transport == BUS_TRANSPORT_LOCAL) {
master = posix_openpt(O_RDWR|O_NOCTTY|O_CLOEXEC|O_NDELAY);
@ -1000,7 +1044,7 @@ static int start_transient_service(
if (!arg_quiet)
log_info("Running as unit: %s", service);
if (arg_wait || master >= 0) {
if (arg_wait || arg_stdio != ARG_STDIO_NONE) {
_cleanup_(run_context_free) RunContext c = {};
_cleanup_free_ char *path = NULL;
const char *mt;
@ -1440,7 +1484,7 @@ int main(int argc, char* argv[]) {
/* If --wait is used connect via the bus, unconditionally, as ref/unref is not supported via the limited direct
* connection */
if (arg_wait || arg_pty)
if (arg_wait || arg_stdio != ARG_STDIO_NONE)
r = bus_connect_transport(arg_transport, arg_host, arg_user, &bus);
else
r = bus_connect_transport_systemd(arg_transport, arg_host, arg_user, &bus);