log: minimize includes in log.h

log.h really should only include the bare minimum of other headers, as
it is really pulled into pretty much everything else and already in
itself one of the most basic pieces of code we have.

Let's hence drop inclusion of:

1. sd-id128.h because it's entirely unneeded in current log.h
2. errno.h, dito.
3. sys/signalfd.h which we can replace by a simple struct forward
   declaration
4. process-util.h which was needed for getpid_cached() which we now hide
   in a funciton log_emergency_level() instead, which nicely abstracts
   the details away.
5. sys/socket.h which was needed for struct iovec, but a simple struct
   forward declaration suffices for that too.

Ultimately this actually makes our source tree larger (since users of
the functionality above must now include it themselves, log.h won't do
that for them), but I think it helps to untangle our web of includes a
tiny bit.

(Background: I'd like to isolate the generic bits of src/basic/ enough
so that we can do a git submodule import into casync for it)

7 files changed, 20 insertions, 5 deletions

diff --git a/src/libelogind/sd-bus/bus-control.c b/src/libelogind/sd-bus/bus-control.c
index c6e3bf99f..819128cbd 100644
--- a/src/libelogind/sd-bus/bus-control.c
+++ b/src/libelogind/sd-bus/bus-control.c
@@ -33,6 +33,7 @@
 #include "bus-message.h"
 #include "bus-util.h"
 #include "capability-util.h"
+//#include "process-util.h"
 #include "stdio-util.h"
 #include "string-util.h"
 #include "strv.h"
diff --git a/src/libelogind/sd-bus/bus-gvariant.c b/src/libelogind/sd-bus/bus-gvariant.c
index 6a990a02c..8730a924c 100644
--- a/src/libelogind/sd-bus/bus-gvariant.c
+++ b/src/libelogind/sd-bus/bus-gvariant.c
@@ -18,6 +18,11 @@
   along with systemd; If not, see <http://www.gnu.org/licenses/>.
 ***/
 
+//#include <errno.h>
+//#include <string.h>
+
+//#include "sd-bus.h"
+
 #include "bus-gvariant.h"
 #include "bus-signature.h"
 #include "bus-type.h"
diff --git a/src/libelogind/sd-bus/bus-signature.c b/src/libelogind/sd-bus/bus-signature.c
index d16461f4a..ba9708c7b 100644
--- a/src/libelogind/sd-bus/bus-signature.c
+++ b/src/libelogind/sd-bus/bus-signature.c
@@ -20,6 +20,8 @@
 
 #include <util.h>
 
+//#include "sd-bus.h"
+
 #include "bus-signature.h"
 #include "bus-type.h"
 
diff --git a/src/libelogind/sd-bus/bus-socket.c b/src/libelogind/sd-bus/bus-socket.c
index bc64779d3..bd0895f27 100644
--- a/src/libelogind/sd-bus/bus-socket.c
+++ b/src/libelogind/sd-bus/bus-socket.c
@@ -38,6 +38,7 @@
 #include "macro.h"
 #include "missing.h"
 //#include "path-util.h"
+//#include "process-util.h"
 #include "selinux-util.h"
 #include "signal-util.h"
 #include "stdio-util.h"
@@ -620,10 +621,13 @@ static void bus_get_peercred(sd_bus *b) {
 
         /* Get the list of auxiliary groups of the peer */
         r = getpeergroups(b->input_fd, &b->groups);
-        if (r >= 0)
+        if (r < 0) {
+                if (!IN_SET(r, -EOPNOTSUPP, -ENOPROTOOPT))
+                        log_debug_errno(r, "Failed to determine peer groups list: %m");
+
+                b->n_groups = (size_t) -1;
+        } else
                 b->n_groups = (size_t) r;
-        else if (!IN_SET(r, -EOPNOTSUPP, -ENOPROTOOPT))
-                log_debug_errno(r, "Failed to determine peer's group list: %m");
 }
 
 static int bus_socket_start_auth_client(sd_bus *b) {
diff --git a/src/libelogind/sd-bus/bus-type.c b/src/libelogind/sd-bus/bus-type.c
index 817040b1a..c580faaf9 100644
--- a/src/libelogind/sd-bus/bus-type.c
+++ b/src/libelogind/sd-bus/bus-type.c
@@ -18,6 +18,10 @@
   along with systemd; If not, see <http://www.gnu.org/licenses/>.
 ***/
 
+//#include <errno.h>
+
+//#include "sd-bus.h"
+
 #include "bus-type.h"
 
 bool bus_type_is_valid(char c) {
diff --git a/src/libelogind/sd-bus/bus-type.h b/src/libelogind/sd-bus/bus-type.h
index ae272b1e6..834f09777 100644
--- a/src/libelogind/sd-bus/bus-type.h
+++ b/src/libelogind/sd-bus/bus-type.h
@@ -22,8 +22,6 @@
 
 #include <stdbool.h>
 
-#include "sd-bus.h"
-
 #include "macro.h"
 
 bool bus_type_is_valid(char c) _const_;
diff --git a/src/libelogind/sd-bus/sd-bus.c b/src/libelogind/sd-bus/sd-bus.c
index 0668df2c1..0a43324b9 100644
--- a/src/libelogind/sd-bus/sd-bus.c
+++ b/src/libelogind/sd-bus/sd-bus.c
@@ -50,6 +50,7 @@
 #include "macro.h"
 #include "missing.h"
 #include "parse-util.h"
+//#include "process-util.h"
 #include "string-util.h"
 #include "strv.h"
 #include "util.h"