kernel: build /kdev/ on the fly

5 files changed, 87 insertions, 50 deletions

diff --git a/src/kernel/arch/amd64/driver/fsroot.c b/src/kernel/arch/amd64/driver/fsroot.c
index ed7e88c..0eef12f 100644
--- a/src/kernel/arch/amd64/driver/fsroot.c
+++ b/src/kernel/arch/amd64/driver/fsroot.c
@@ -2,59 +2,90 @@
 #include <camellia/fsutil.h>
 #include <kernel/arch/amd64/driver/driver.h>
 #include <kernel/arch/amd64/driver/util.h>
+#include <kernel/malloc.h>
 #include <kernel/panic.h>
 #include <kernel/proc.h>
 #include <kernel/util.h>
+#include <kernel/vfs/mount.h>
 #include <kernel/vfs/request.h>
 #include <shared/mem.h>
 
-static long handle(VfsReq *req) {
-	// TODO document directory read format
-	// TODO don't hardcode
-	static const char base[] = "kdev/";
-	static const char dir[] =
-		"com1\0"
-		"ps2/\0"
-		"ata/\0"
-		"eth\0"
-		"video/";
-	const char *id;
-	int len;
+enum {
+	Hbase,
+	Hkdev,
+};
+
+static int
+get_kdev(char *lst)
+{
+	int len = 0;
+	for (VfsMount *m = vfs_mount_seed(); m; m = m->prev) {
+		if (m->prefix_len == 0) {
+			continue; /* that's us */
+		}
+		assert(m->prefix_len > 6);
+		assert(memcmp(m->prefix, "/kdev/", 6) == 0);
+		len += m->prefix_len - 6 + 1;
+		if (lst) {
+			memcpy(lst, m->prefix + 6, m->prefix_len - 6);
+			lst += m->prefix_len - 6;
+			*lst++ = '\0';
+		}
+	}
+	return len;
+}
+
+static long
+handle(VfsReq *req)
+{
+	static char *kdev = NULL;
+	static int kdev_len = 0;
+	const char *lst = NULL;
+	int len = 0;
 
 	if (!req->caller) return -1;
 	if (req->type != VFSOP_OPEN) {
-		/* otherwise, uninitialized, to cause compiler warnings if used */
-		/* this operates under the assumption that base and dir never change
-		 * but even if they do, that will just result in a crash. */
-		id = (void *__force)req->id;
-		if (id == base) {
-			len = sizeof base;
-		} else if (id == dir) {
-			len = sizeof dir;
-		} else {
-			kprintf("%p %p %p\n", base, dir, id);
+		switch ((uintptr_t __force)req->id) {
+		case Hbase:
+			lst = "kdev/";
+			len = strlen(lst) + 1;
+			break;
+		case Hkdev:
+			if (!kdev) {
+				kdev_len = get_kdev(NULL);
+				kdev = kmalloc(kdev_len);
+				get_kdev(kdev);
+			}
+			lst = kdev;
+			len = kdev_len;
+			break;
+		default:
 			assert(false);
 		}
 	}
 
 	switch (req->type) {
-		case VFSOP_OPEN:
-			if (reqpathcmp(req, "/")) return (long)base;
-			if (reqpathcmp(req, "/kdev/")) return (long)dir;
-			return -ENOENT;
-
-		case VFSOP_READ:
-			return req_readcopy(req, id, len);
-		// TODO getsize for the other kernel provided directories
-		case VFSOP_GETSIZE:
-			return len;
-		default:
-			return -ENOSYS;
+	case VFSOP_OPEN:
+		if (reqpathcmp(req, "/")) return Hbase;
+		if (reqpathcmp(req, "/kdev/")) return Hkdev;
+		return -ENOENT;
+	case VFSOP_READ:
+		return req_readcopy(req, lst, len);
+	case VFSOP_GETSIZE:
+		return len;
+	default:
+		return -ENOSYS;
 	}
 }
 
-static void accept(VfsReq *req) {
+static void
+accept(VfsReq *req)
+{
 	vfsreq_finish_short(req, handle(req));
 }
 
-void vfs_root_init(void) { vfs_root_register("", accept); }
+void
+vfs_root_init(void)
+{
+	vfs_root_register("", accept);
+}
diff --git a/src/kernel/arch/amd64/driver/pata.c b/src/kernel/arch/amd64/driver/pata.c
index b0058f8..da8b541 100644
--- a/src/kernel/arch/amd64/driver/pata.c
+++ b/src/kernel/arch/amd64/driver/pata.c
@@ -13,7 +13,7 @@ static const int root_id = 100;
 static void accept(VfsReq *req);
 void pata_init(void) {
 	ata_init();
-	vfs_root_register("/kdev/ata", accept);
+	vfs_root_register("/kdev/ata/", accept);
 }
 
 static void accept(VfsReq *req) {
@@ -23,11 +23,11 @@ static void accept(VfsReq *req) {
 	size_t len;
 	switch (req->type) {
 		case VFSOP_OPEN:
-			     if (reqpathcmp(req, "/"))  ret = root_id;
-			else if (reqpathcmp(req, "/0")) ret = 0;
-			else if (reqpathcmp(req, "/1")) ret = 1;
-			else if (reqpathcmp(req, "/2")) ret = 2;
-			else if (reqpathcmp(req, "/3")) ret = 3;
+			     if (reqpathcmp(req, ""))  ret = root_id;
+			else if (reqpathcmp(req, "0")) ret = 0;
+			else if (reqpathcmp(req, "1")) ret = 1;
+			else if (reqpathcmp(req, "2")) ret = 2;
+			else if (reqpathcmp(req, "3")) ret = 3;
 			else ret = -ENOENT;
 			// TODO don't allow opening nonexistent drives
 			vfsreq_finish_short(req, ret);
@@ -70,6 +70,7 @@ static void accept(VfsReq *req) {
 
 		case VFSOP_GETSIZE:
 			if (id == root_id) {
+				// TODO getsize for all kernel provided directories
 				panic_unimplemented();
 			}
 			vfsreq_finish_short(req, ata_size(id));
diff --git a/src/kernel/arch/amd64/driver/ps2.c b/src/kernel/arch/amd64/driver/ps2.c
index e314477..f2a98a2 100644
--- a/src/kernel/arch/amd64/driver/ps2.c
+++ b/src/kernel/arch/amd64/driver/ps2.c
@@ -58,7 +58,7 @@ void ps2_init(void) {
 	irq_fn[IRQ_PS2KB] = ps2_irq;
 	irq_fn[IRQ_PS2MOUSE] = ps2_irq;
 
-	vfs_root_register("/kdev/ps2", accept);
+	vfs_root_register("/kdev/ps2/", accept);
 }
 
 static void ps2_irq(void) {
@@ -86,10 +86,10 @@ static void accept(VfsReq *req) {
 	int ret;
 	switch (req->type) {
 		case VFSOP_OPEN:
-			     if (reqpathcmp(req, "/"))      ret = H_ROOT;
-			else if (reqpathcmp(req, "/kb"))    ret = H_KB;
-			else if (reqpathcmp(req, "/mouse")) ret = H_MOUSE;
-			else                                ret = -ENOENT;
+			     if (reqpathcmp(req, ""))      ret = H_ROOT;
+			else if (reqpathcmp(req, "kb"))    ret = H_KB;
+			else if (reqpathcmp(req, "mouse")) ret = H_MOUSE;
+			else                               ret = -ENOENT;
 			vfsreq_finish_short(req, ret);
 			break;
 		case VFSOP_READ:
diff --git a/src/kernel/arch/amd64/driver/video.c b/src/kernel/arch/amd64/driver/video.c
index 5a7fc8f..390e8dd 100644
--- a/src/kernel/arch/amd64/driver/video.c
+++ b/src/kernel/arch/amd64/driver/video.c
@@ -21,9 +21,9 @@ static int handle(VfsReq *req) {
 	switch (req->type) {
 		case VFSOP_OPEN:
 			if (!req->input.kern) panic_invalid_state();
-			if (req->input.len == 1) {
+			if (req->input.len == 0) {
 				return H_ROOT;
-			} else if (req->input.len == namelen + 1 && !memcmp(req->input.buf_kern + 1, namebuf, namelen)) {
+			} else if (req->input.len == namelen && !memcmp(req->input.buf_kern, namebuf, namelen)) {
 				return H_FB;
 			} else {
 				return -1;
@@ -65,5 +65,5 @@ void video_init(GfxInfo fb_) {
 	fb = fb_;
 	snprintf(namebuf, sizeof namebuf, "%ux%ux%u", fb.width, fb.height, fb.bpp);
 	namelen = strlen(namebuf);
-	vfs_root_register("/kdev/video", accept);
+	vfs_root_register("/kdev/video/", accept);
 }
diff --git a/src/kernel/vfs/mount.c b/src/kernel/vfs/mount.c
index b4f5b0f..c153c69 100644
--- a/src/kernel/vfs/mount.c
+++ b/src/kernel/vfs/mount.c
@@ -45,6 +45,11 @@ VfsMount *vfs_mount_resolve(
 			break;
 		if (path[top->prefix_len] == '/')
 			break;
+
+		/* Also valid if prefix ends with '/'. Can only happen with kernel-
+		 * provided mounts. */
+		if (top->prefix_len != 0 && path[top->prefix_len-1] == '/')
+			break;
 	}
 	return top;
 }