From 9a3eec7d4d7fbf7f6983facc66af03f568007df1 Mon Sep 17 00:00:00 2001
From: Michal Moskal <michal@moskal.me>
Date: Tue, 25 Jul 2017 19:09:32 +0100
Subject: [PATCH] dmesg logging

---
 brick/ins              |  3 ++-
 brick/uf2daemon/main.c | 28 +++++++++++++++++++++++++---
 brick/uf2daemon/uf2.h  | 15 ++++-----------
 3 files changed, 31 insertions(+), 15 deletions(-)

diff --git a/brick/ins b/brick/ins
index abeb7604..5d4370b2 100755
--- a/brick/ins
+++ b/brick/ins
@@ -1,7 +1,8 @@
 #!/bin/sh
 set -ex
+echo Y > /sys/module/printk/parameters/time
 cd /mnt/ramdisk/prjs/ko
-echo 3 > /proc/sys/kernel/printk
+#echo 3 > /proc/sys/kernel/printk
 insmod ./nbd.ko
 sleep 1
 ./uf2d > /tmp/uf2d.log 2> /tmp/uf2derr.log
diff --git a/brick/uf2daemon/main.c b/brick/uf2daemon/main.c
index 0910baf0..b207827e 100644
--- a/brick/uf2daemon/main.c
+++ b/brick/uf2daemon/main.c
@@ -16,6 +16,7 @@
 #include <sys/stat.h>
 #include <unistd.h>
 #include <sys/wait.h>
+#include <stdarg.h>
 
 #include "uf2.h"
 
@@ -26,6 +27,27 @@ uint64_t ntohll(uint64_t a) {
 }
 #define htonll ntohll
 
+void mylog(const char *fmt, ...) {
+    va_list args;
+    char *p;
+
+    va_start(args, fmt);
+    vasprintf(&p, fmt, args);
+    vprintf(fmt, args);
+    va_end(args);
+
+    int len = strlen(p) + 1;
+    p[len - 1] = '\n';
+
+#ifdef X86
+    write(2, p, len);
+#else
+    int fd = open("/dev/kmsg", O_WRONLY);
+    write(fd, p, len);
+    close(fd);
+#endif
+}
+
 void readAll(int fd, void *dst, uint32_t length) {
     while (length) {
         int curr = read(fd, dst, length);
@@ -71,7 +93,7 @@ void startclient() {
 
 void handleread(int off, int len) {
     uint8_t buf[512];
-    //LOG("read @%d len=%d", off, len);
+    // LOG("read @%d len=%d", off, len);
     reply.error = 0; //  htonl(EPERM);
     writeAll(sock, &reply, sizeof(struct nbd_reply));
     for (int i = 0; i < len; ++i) {
@@ -82,7 +104,7 @@ void handleread(int off, int len) {
 
 void handlewrite(int off, int len) {
     uint8_t buf[512];
-    //LOG("write @%d len=%d", off, len);
+    // LOG("write @%d len=%d", off, len);
     for (int i = 0; i < len; ++i) {
         readAll(sock, buf, 512);
         write_block(off + i, buf);
@@ -121,7 +143,7 @@ void runNBD() {
     reply.error = htonl(0);
 
     for (;;) {
-        //nbd_ioctl(BLKFLSBUF, 0); // flush buffers - we don't want the kernel to cache the writes
+        // nbd_ioctl(BLKFLSBUF, 0); // flush buffers - we don't want the kernel to cache the writes
         int nread = read(sock, &request, sizeof(request));
 
         if (nread < 0) {
diff --git a/brick/uf2daemon/uf2.h b/brick/uf2daemon/uf2.h
index 168ce081..25431c38 100644
--- a/brick/uf2daemon/uf2.h
+++ b/brick/uf2daemon/uf2.h
@@ -25,8 +25,7 @@ void write_block(uint32_t block_no, uint8_t *data);
 
 #define CONCAT_1(a, b) a##b
 #define CONCAT_0(a, b) CONCAT_1(a, b)
-#define STATIC_ASSERT(e)                                                       \
-  enum { CONCAT_0(_static_assert_, __LINE__) = 1 / ((e) ? 1 : 0) }
+#define STATIC_ASSERT(e) enum { CONCAT_0(_static_assert_, __LINE__) = 1 / ((e) ? 1 : 0) }
 
 extern const char infoUf2File[];
 
@@ -34,20 +33,14 @@ void readAll(int fd, void *dst, uint32_t length);
 
 STATIC_ASSERT(sizeof(UF2_Block) == 512);
 
+void mylog(const char *fmt, ...);
 
 #define FAIL(args...)                                                                              \
     do {                                                                                           \
-        fprintf(stderr, args);                                                                     \
-        fprintf(stderr, "\n");                                                                     \
+        mylog(args);                                                                                 \
         exit(1);                                                                                   \
     } while (0)
 
-#define LOG(args...)                                                                               \
-    do {                                                                                           \
-        fprintf(stderr, args);                                                                     \
-        fprintf(stderr, "\n");                                                                     \
-        fflush(stderr);                                                                            \
-    } while (0)
-
+#define LOG mylog
 
 #endif