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core: implement /run/systemd/units/-based path for passing unit info from PID 1 to journald

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And let's make use of it to implement two new unit settings with it:

1. LogLevelMax= is a new per-unit setting that may be used to configure
   log priority filtering: set it to LogLevelMax=notice and only
   messages of level "notice" and lower (i.e. more important) will be
   processed, all others are dropped.

2. LogExtraFields= is a new per-unit setting for configuring per-unit
   journal fields, that are implicitly included in every log record
   generated by the unit's processes. It takes field/value pairs in the
   form of FOO=BAR.

Also, related to this, one exisiting unit setting is ported to this new
facility:

3. The invocation ID is now pulled from /run/systemd/units/ instead of
   cgroupfs xattrs. This substantially relaxes requirements of systemd
   on the kernel version and the privileges it runs with (specifically,
   cgroupfs xattrs are not available in containers, since they are
   stored in kernel memory, and hence are unsafe to permit to lesser
   privileged code).

/run/systemd/units/ is a new directory, which contains a number of files
and symlinks encoding the above information. PID 1 creates and manages
these files, and journald reads them from there.

Note that this is supposed to be a direct path between PID 1 and the
journal only, due to the special runtime environment the journal runs
in. Normally, today we shouldn't introduce new interfaces that (mis-)use
a file system as IPC framework, and instead just an IPC system, but this
is very hard to do between the journal and PID 1, as long as the IPC
system is a subject PID 1 manages, and itself a client to the journal.

This patch cleans up a couple of types used in journal code:
specifically we switch to size_t for a couple of memory-sizing values,
as size_t is the right choice for everything that is memory.

Fixes: #4089
Fixes: #3041
Fixes: #4441
This commit is contained in:
Lennart Poettering
2017-11-16 12:40:17 +01:00
parent 4d14b2bd35
commit d3070fbdf6
27 changed files with 767 additions and 88 deletions
Download Patch File Download Diff File Expand all files Collapse all files
src/core/dbus-execute.c
+128 -1
View File
@@ -26,15 +26,17 @@
#include "af-list.h"
#include "alloc-util.h"
#include "bus-util.h"
#include "capability-util.h"
#include "cap-list.h"
#include "capability-util.h"
#include "dbus-execute.h"
#include "env-util.h"
#include "errno-list.h"
#include "execute.h"
#include "fd-util.h"
#include "fileio.h"
#include "io-util.h"
#include "ioprio.h"
#include "journal-util.h"
#include "missing.h"
#include "mount-util.h"
#include "namespace.h"
@@ -771,6 +773,37 @@ static int property_get_bind_paths(
return sd_bus_message_close_container(reply);
}
static int property_get_log_extra_fields(
sd_bus *bus,
const char *path,
const char *interface,
const char *property,
sd_bus_message *reply,
void *userdata,
sd_bus_error *error) {
ExecContext *c = userdata;
size_t i;
int r;
assert(bus);
assert(c);
assert(property);
assert(reply);
r = sd_bus_message_open_container(reply, 'a', "ay");
if (r < 0)
return r;
for (i = 0; i < c->n_log_extra_fields; i++) {
r = sd_bus_message_append_array(reply, 'y', c->log_extra_fields[i].iov_base, c->log_extra_fields[i].iov_len);
if (r < 0)
return r;
}
return sd_bus_message_close_container(reply);
}
const sd_bus_vtable bus_exec_vtable[] = {
SD_BUS_VTABLE_START(0),
SD_BUS_PROPERTY("Environment", "as", NULL, offsetof(ExecContext, environment), SD_BUS_VTABLE_PROPERTY_CONST),
@@ -838,6 +871,8 @@ const sd_bus_vtable bus_exec_vtable[] = {
SD_BUS_PROPERTY("SyslogLevelPrefix", "b", bus_property_get_bool, offsetof(ExecContext, syslog_level_prefix), SD_BUS_VTABLE_PROPERTY_CONST),
SD_BUS_PROPERTY("SyslogLevel", "i", property_get_syslog_level, 0, SD_BUS_VTABLE_PROPERTY_CONST),
SD_BUS_PROPERTY("SyslogFacility", "i", property_get_syslog_facility, 0, SD_BUS_VTABLE_PROPERTY_CONST),
SD_BUS_PROPERTY("LogLevelMax", "i", bus_property_get_int, offsetof(ExecContext, log_level_max), SD_BUS_VTABLE_PROPERTY_CONST),
SD_BUS_PROPERTY("LogExtraFields", "aay", property_get_log_extra_fields, 0, SD_BUS_VTABLE_PROPERTY_CONST),
SD_BUS_PROPERTY("SecureBits", "i", bus_property_get_int, offsetof(ExecContext, secure_bits), SD_BUS_VTABLE_PROPERTY_CONST),
SD_BUS_PROPERTY("CapabilityBoundingSet", "t", property_get_capability_bounding_set, 0, SD_BUS_VTABLE_PROPERTY_CONST),
SD_BUS_PROPERTY("AmbientCapabilities", "t", property_get_ambient_capabilities, 0, SD_BUS_VTABLE_PROPERTY_CONST),
@@ -1137,6 +1172,98 @@ int bus_exec_context_set_transient_property(
}
return 1;
} else if (streq(name, "LogLevelMax")) {
int32_t level;
r = sd_bus_message_read(message, "i", &level);
if (r < 0)
return r;
if (!log_level_is_valid(level))
return sd_bus_error_setf(error, SD_BUS_ERROR_INVALID_ARGS, "Maximum log level value out of range");
if (mode != UNIT_CHECK) {
c->log_level_max = level;
unit_write_drop_in_private_format(u, mode, name, "LogLevelMax=%i", level);
}
return 1;
} else if (streq(name, "LogExtraFields")) {
size_t n = 0;
r = sd_bus_message_enter_container(message, 'a', "ay");
if (r < 0)
return r;
for (;;) {
_cleanup_free_ void *copy = NULL;
struct iovec *t;
const char *eq;
const void *p;
size_t sz;
/* Note that we expect a byte array for each field, instead of a string. That's because on the
* lower-level journal fields can actually contain binary data and are not restricted to text,
* and we should not "lose precision" in our types on the way. That said, I am pretty sure
* actually encoding binary data as unit metadata is not a good idea. Hence we actually refuse
* any actual binary data, and only accept UTF-8. This allows us to eventually lift this
* limitation, should a good, valid usecase arise. */
r = sd_bus_message_read_array(message, 'y', &p, &sz);
if (r < 0)
return r;
if (r == 0)
break;
if (memchr(p, 0, sz))
return sd_bus_error_setf(error, SD_BUS_ERROR_INVALID_ARGS, "Journal field contains zero byte");
eq = memchr(p, '=', sz);
if (!eq)
return sd_bus_error_setf(error, SD_BUS_ERROR_INVALID_ARGS, "Journal field contains no '=' character");
if (!journal_field_valid(p, eq - (const char*) p, false))
return sd_bus_error_setf(error, SD_BUS_ERROR_INVALID_ARGS, "Journal field invalid");
if (mode != UNIT_CHECK) {
t = realloc_multiply(c->log_extra_fields, sizeof(struct iovec), c->n_log_extra_fields+1);
if (!t)
return -ENOMEM;
c->log_extra_fields = t;
}
copy = malloc(sz + 1);
if (!copy)
return -ENOMEM;
memcpy(copy, p, sz);
((uint8_t*) copy)[sz] = 0;
if (!utf8_is_valid(copy))
return sd_bus_error_setf(error, SD_BUS_ERROR_INVALID_ARGS, "Journal field is not valid UTF-8");
if (mode != UNIT_CHECK) {
c->log_extra_fields[c->n_log_extra_fields++] = IOVEC_MAKE(copy, sz);
unit_write_drop_in_private_format(u, mode, name, "LogExtraFields=%s", (char*) copy);
copy = NULL;
}
n++;
}
r = sd_bus_message_exit_container(message);
if (r < 0)
return r;
if (mode != UNIT_CHECK && n == 0) {
exec_context_free_log_extra_fields(c);
unit_write_drop_in_private(u, mode, name, "LogExtraFields=");
}
return 1;
} else if (streq(name, "SecureBits")) {
int n;