systemd/log-target-null-instead-kmsg.patch

---
 src/journal/journald-kmsg.c |   16 +++++++++++++++-
 src/libudev/libudev-util.c  |   16 +++++++++++++++-
 src/shared/log.c            |   16 +++++++++++++++-
 src/shared/util.c           |    6 +++++-
 4 files changed, 50 insertions(+), 4 deletions(-)

Index: systemd-210/src/journal/journald-kmsg.c
===================================================================
--- systemd-210.orig/src/journal/journald-kmsg.c
+++ systemd-210/src/journal/journald-kmsg.c
@@ -391,12 +391,24 @@ static int dispatch_dev_kmsg(sd_event_so
         return server_read_dev_kmsg(s);
 }
 
+static int parse_proc_cmdline_word(const char *word) {
+        if (streq(word, "systemd.log_target=null"))
+                return -115;
+
+        return 0;
+}
+
 int server_open_dev_kmsg(Server *s) {
         int r;
 
         assert(s);
 
-        s->dev_kmsg_fd = open("/dev/kmsg", O_RDWR|O_CLOEXEC|O_NONBLOCK|O_NOCTTY);
+        if (parse_proc_cmdline(parse_proc_cmdline_word) == -115) {
+                s->dev_kmsg_fd = open("/dev/null", O_RDWR|O_CLOEXEC|O_NONBLOCK|O_NOCTTY);
+        } else {
+                s->dev_kmsg_fd = open("/dev/kmsg", O_RDWR|O_CLOEXEC|O_NONBLOCK|O_NOCTTY);
+        }
+
         if (s->dev_kmsg_fd < 0) {
                 log_full(errno == ENOENT ? LOG_DEBUG : LOG_WARNING,
                          "Failed to open /dev/kmsg, ignoring: %m");
Index: systemd-210/src/libudev/libudev-util.c
===================================================================
--- systemd-210.orig/src/libudev/libudev-util.c
+++ systemd-210/src/libudev/libudev-util.c
@@ -416,6 +416,13 @@ uint64_t util_string_bloom64(const char
         return bits;
 }
 
+static int parse_proc_cmdline_word(const char *word) {
+        if (streq(word, "systemd.log_target=null"))
+                return -115;
+
+        return 0;
+}
+
 ssize_t print_kmsg(const char *fmt, ...)
 {
         _cleanup_close_ int fd = -1;
@@ -424,7 +431,12 @@ ssize_t print_kmsg(const char *fmt, ...)
         ssize_t len;
         ssize_t ret;
 
-        fd = open("/dev/kmsg", O_WRONLY|O_NOCTTY|O_CLOEXEC);
+        if (parse_proc_cmdline(parse_proc_cmdline_word) == -115) {
+                fd = open("/dev/null", O_WRONLY|O_NOCTTY|O_CLOEXEC);
+        } else {
+                fd = open("/dev/kmsg", O_WRONLY|O_NOCTTY|O_CLOEXEC);
+        }
+
         if (fd < 0)
                 return -errno;
 
Index: systemd-210/src/shared/log.c
===================================================================
--- systemd-210.orig/src/shared/log.c
+++ systemd-210/src/shared/log.c
@@ -92,12 +92,24 @@ void log_close_kmsg(void) {
         kmsg_fd = -1;
 }
 
+static int parse_proc_cmdline_word(const char *word) {
+        if (streq(word, "systemd.log_target=null"))
+                return -115;
+
+        return 0;
+}
+
 static int log_open_kmsg(void) {
 
         if (kmsg_fd >= 0)
                 return 0;
 
-        kmsg_fd = open("/dev/kmsg", O_WRONLY|O_NOCTTY|O_CLOEXEC);
+        if (parse_proc_cmdline(parse_proc_cmdline_word) == -115) {
+                kmsg_fd = open("/dev/null", O_WRONLY|O_NOCTTY|O_CLOEXEC);
+        } else {
+                kmsg_fd = open("/dev/kmsg", O_WRONLY|O_NOCTTY|O_CLOEXEC);
+        }
+
         if (kmsg_fd < 0)
                 return -errno;
 
Index: systemd-210/src/shared/util.c
===================================================================
--- systemd-210.orig/src/shared/util.c
+++ systemd-210/src/shared/util.c
@@ -6069,7 +6069,11 @@ int parse_proc_cmdline(int (*parse_word)
 
                 r = parse_word(word);
                 if (r < 0) {
-                        log_error("Failed on cmdline argument %s: %s", word, strerror(-r));
+                        if (r == -115) {
+                                log_error("Warning: %s set, redirecting messages to /dev/null.", word);
+                        } else {
+                                log_error("Failed on cmdline argument %s: %s", word, strerror(-r));
+                        }
                         return r;
                 }
         }