Add pseudo devices

etc/make/conf.mk

@@ -65,7 +65,8 @@ OBJS+=$(O)/sys/debug.o \
 	  $(O)/sys/net/arp.o \
 	  $(O)/sys/net/in.o \
 	  $(O)/sys/net/netdev.o \
-	  $(O)/sys/vfs/devfs.o
+	  $(O)/sys/vfs/devfs.o \
+	  $(O)/sys/vfs/pseudo.o
 DIRS+=$(O)/sys/vfs/ext2 \
 	  $(O)/sys/net \
 	  $(O)/sys/blk

include/sys/chr.h

@@ -2,7 +2,6 @@
 #include "sys/types.h"
 
 struct chrdev {
-    char name[64];
     void *dev_data;
 
     // TODO: maybe something like flush()

include/sys/dev.h

@@ -13,6 +13,7 @@ enum dev_class {
 #define DEV_BLOCK_HDx       2
 #define DEV_BLOCK_RAM       3
 #define DEV_BLOCK_PART      127
+#define DEV_BLOCK_PSEUDO    128
 
 struct dev_entry {
     char dev_name[64];

sys/dev.c

@@ -51,7 +51,7 @@ static int dev_post_add(struct dev_entry *ent) {
 
         blk->ent = ent;
 
-        if (ent->dev_subclass != DEV_BLOCK_PART) {
+        if (ent->dev_subclass < DEV_BLOCK_PART) {
             if (blk_enumerate_partitions((struct blkdev *) ent->dev) != 0) {
                 return -1;
             }

sys/tty.c

@@ -17,7 +17,6 @@ static ssize_t tty_write(struct chrdev *tty, const void *buf, size_t pos, size_t
 static ssize_t tty_read(struct chrdev *tty, void *buf, size_t pos, size_t lim);
 
 static struct chrdev _dev_tty0 = {
-    .name = "tty0",
     .dev_data = DEV_DATA_TTY(0),
     .write = tty_write,
     .read = tty_read

sys/vfs/pseudo.c

@@ -0,0 +1,61 @@
+#include "sys/string.h"
+#include "sys/panic.h"
+#include "sys/attr.h"
+#include "sys/blk.h"
+#include "sys/dev.h"
+
+#define DEV_ZERO        0
+#define DEV_NULL        1
+
+static ssize_t pseudo_write(struct blkdev *dev, const void *buf, size_t pos, size_t lim);
+static ssize_t pseudo_read(struct blkdev *dev, void *buf, size_t pos, size_t lim);
+
+static struct blkdev _dev_null = {
+    .dev_data = (void *) DEV_NULL,
+    .write = pseudo_write,
+    .read = pseudo_read
+};
+static struct dev_entry _ent_null = {
+    .dev = &_dev_null,
+    .dev_class = DEV_CLASS_BLOCK,
+    .dev_subclass = DEV_BLOCK_PSEUDO,
+    .dev_name = "null"
+};
+static struct blkdev _dev_zero = {
+    .dev_data = (void *) DEV_ZERO,
+    .write = pseudo_write,
+    .read = pseudo_read
+};
+static struct dev_entry _ent_zero = {
+    .dev = &_dev_zero,
+    .dev_class = DEV_CLASS_BLOCK,
+    .dev_subclass = DEV_BLOCK_PSEUDO,
+    .dev_name = "zero"
+};
+
+static ssize_t pseudo_write(struct blkdev *dev, const void *buf, size_t pos, size_t lim) {
+    switch ((uint64_t) dev->dev_data) {
+    case DEV_NULL:
+    case DEV_ZERO:
+        return lim;
+    default:
+        panic("Unexpected dev id: %p\n", dev->dev_data);
+    }
+}
+
+static ssize_t pseudo_read(struct blkdev *dev, void *buf, size_t pos, size_t lim) {
+    switch ((uint64_t) dev->dev_data) {
+    case DEV_ZERO:
+        memset(buf, 0, lim);
+        return lim;
+    case DEV_NULL:
+        return 0;
+    default:
+        panic("Unexpected dev id: %p\n", dev->dev_data);
+    }
+}
+
+static __init void pseudo_init(void) {
+    dev_entry_add(&_ent_null);
+    dev_entry_add(&_ent_zero);
+}