coredump: handle ENOBUFS and EMSGSIZE the same way

Depending on the runtime configuration, e.g. sysctls
net.core.wmem_default= and net.core.rmem_default and on the actual
message size, sendmsg() can fail also with ENOBUFS. E.g. alloc_skb()
failure caused by net.core.[rw]mem_default=64MiB and huge fdinfo list
from process that has 90k opened FDs.

We should handle this case in the same way as EMSGSIZE and drop part of
the message.

mkosi/mkosi.conf.d/centos-fedora/mkosi.conf

@@ -9,7 +9,6 @@ PrepareScripts=systemd.prepare
 VolatilePackages=
         systemd
         systemd-container
-        systemd-devel
         systemd-journal-remote
         systemd-libs
         systemd-networkd

mkosi/mkosi.conf.d/debian-ubuntu/mkosi.conf

@@ -12,10 +12,8 @@ VolatilePackages=
         libnss-resolve
         libnss-systemd
         libpam-systemd
-        libsystemd-dev
         libsystemd-shared
         libsystemd0
-        libudev-dev
         systemd
         systemd-container
         systemd-coredump

mkosi/mkosi.conf.d/opensuse/mkosi.conf

@@ -17,7 +17,6 @@ VolatilePackages=
         libudev1
         systemd
         systemd-container
-        systemd-devel
         systemd-doc
         systemd-experimental
         systemd-homed
@@ -71,6 +70,7 @@ Packages=
         pam
         patterns-base-minimal_base
         perf
+        policycoreutils
         pkgconf
         procps4
         psmisc
@@ -81,6 +81,8 @@ Packages=
         quota
         rsync
         sed
+        selinux-policy
+        selinux-policy-targeted
         shadow
         softhsm
         squashfs

src/coredump/coredump-send.c

@@ -45,7 +45,7 @@ int coredump_send(const struct iovec_wrapper *iovw, int input_fd, PidRef *pidref
                         if (sendmsg(fd, &mh, MSG_NOSIGNAL) >= 0)
                                 break;
 
-                        if (errno == EMSGSIZE && mh.msg_iov[0].iov_len > 0) {
+                        if (IN_SET(errno, EMSGSIZE, ENOBUFS) && mh.msg_iov[0].iov_len > 0) {
                                 /* This field didn't fit? That's a pity. Given that this is
                                  * just metadata, let's truncate the field at half, and try
                                  * again. We append three dots, in order to show that this is