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

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/elogind/units/ instead of
   cgroupfs xattrs. This substantially relaxes requirements of elogind
   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/elogind/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

diff --git a/src/basic/log.c b/src/basic/log.c
index 04d85e7ea8d55ae002ad3575ccdf5385450fa5d2..3367f8424b2c76b497925d61d155807422af0441 100644 (file)
--- a/src/basic/log.c
+++ b/src/basic/log.c
@@ -863,8 +863,8 @@ int log_oom_internal(LogRealm realm, const char *file, int line, const char *fun
 
 int log_format_iovec(
                 struct iovec *iovec,
-                unsigned iovec_len,
-                unsigned *n,
+                size_t iovec_len,
+                size_t *n,
                 bool newline_separator,
                 int error,
                 const char *format,
@@ -945,7 +945,7 @@ int log_struct_internal(
                 if (journal_fd >= 0) {
                         char header[LINE_MAX];
                         struct iovec iovec[17] = {};
-                        unsigned n = 0, i;
+                        size_t n = 0, i;
                         int r;
                         struct msghdr mh = {
                                 .msg_iov = iovec,

diff --git a/src/basic/log.h b/src/basic/log.h
index c4d089b19f92e24a0f2241486b9545cda1244b52..7b67fd45bcfebc9ea3c1c03a79011a471769cd16 100644 (file)
--- a/src/basic/log.h
+++ b/src/basic/log.h
@@ -182,8 +182,8 @@ int log_oom_internal(
 
 int log_format_iovec(
                 struct iovec *iovec,
-                unsigned iovec_len,
-                unsigned *n,
+                size_t iovec_len,
+                size_t *n,
                 bool newline_separator,
                 int error,
                 const char *format,

diff --git a/src/shared/conf-parser.c b/src/shared/conf-parser.c
index b95cd0fd582cbf80342d927da98fc27df034e0e6..59fa4d81e6285fc1a050795df7d5ddb8909ad503 100644 (file)
--- a/src/shared/conf-parser.c
+++ b/src/shared/conf-parser.c
@@ -851,7 +851,6 @@ int config_parse_log_facility(
                 void *data,
                 void *userdata) {
 
-
         int *o = data, x;
 
         assert(filename);
@@ -883,7 +882,6 @@ int config_parse_log_level(
                 void *data,
                 void *userdata) {
 
-
         int *o = data, x;
 
         assert(filename);
@@ -897,7 +895,11 @@ int config_parse_log_level(
                 return 0;
         }
 
-        *o = (*o & LOG_FACMASK) | x;
+        if (*o < 0) /* if it wasn't initialized so far, assume zero facility */
+                *o = x;
+        else
+                *o = (*o & LOG_FACMASK) | x;
+
         return 0;
 }