From a24be5cbc5231df3b4a6484df743426188535eb8 Mon Sep 17 00:00:00 2001
From: Matheus <matheusuky@gmail.com>
Date: Sun, 11 Aug 2024 13:06:46 -0300
Subject: [PATCH] fs: binding of pipes to vnodes

---
 kernel-src/fs/ext2.c               | 18 +++++++++++++++---
 kernel-src/fs/pipefs.c             | 17 +++++++++++++++++
 kernel-src/fs/tmpfs.c              | 19 +++++++++++++++----
 kernel-src/include/kernel/pipefs.h |  1 +
 kernel-src/include/kernel/vfs.h    |  6 +++++-
 5 files changed, 53 insertions(+), 8 deletions(-)

diff --git a/kernel-src/fs/ext2.c b/kernel-src/fs/ext2.c
index 8c698eed..1fa7e432 100644
--- a/kernel-src/fs/ext2.c
+++ b/kernel-src/fs/ext2.c
@@ -10,6 +10,7 @@
 #include <logging.h>
 #include <util.h>
 #include <kernel/vmmcache.h>
+#include <kernel/pipefs.h>
 
 #define INODE_ROOT 2
 
@@ -1052,9 +1053,20 @@ static void freeinode(ext2fs_t *fs, inode_t *inode, int id) {
 static int ext2_open(vnode_t **vnodep, int flags, cred_t *cred) {
 	vnode_t *vnode = *vnodep;
 	int type = vnode->type;
-	// TODO these types of files
-	__assert(type == V_TYPE_REGULAR || type == V_TYPE_DIR || type == V_TYPE_LINK);
-	return 0;
+	// TODO device files
+	__assert(type == V_TYPE_REGULAR || type == V_TYPE_DIR || type == V_TYPE_LINK || type == V_TYPE_FIFO);
+
+	int error = 0;
+	if (type == V_TYPE_FIFO) {
+		VOP_LOCK(*vnodep);
+		vnode_t *fifo;
+		error = pipefs_getbinding(*vnodep, &fifo);
+		VOP_UNLOCK(*vnodep);
+		if (error == 0)
+			*vnodep = fifo;
+	}
+
+	return error;
 }
 
 static int ext2_close(vnode_t *vnode, int flags, cred_t *cred) {
diff --git a/kernel-src/fs/pipefs.c b/kernel-src/fs/pipefs.c
index 20f9a152..3ee3404e 100644
--- a/kernel-src/fs/pipefs.c
+++ b/kernel-src/fs/pipefs.c
@@ -399,3 +399,20 @@ int pipefs_newpipe(vnode_t **nodep) {
 
 	return 0;
 }
+
+// assumes node is locked upon calling
+int pipefs_getbinding(vnode_t *node, vnode_t **pipep) {
+	__assert(node->type == V_TYPE_FIFO);
+
+	if (node->fifobinding) {
+		*pipep = node->fifobinding;
+		return 0;
+	}
+
+	int error = pipefs_newpipe(pipep);
+	if (error)
+		return error;
+
+	node->fifobinding = *pipep;
+	return error;
+}
diff --git a/kernel-src/fs/tmpfs.c b/kernel-src/fs/tmpfs.c
index 96a91301..ab86d9bb 100644
--- a/kernel-src/fs/tmpfs.c
+++ b/kernel-src/fs/tmpfs.c
@@ -13,6 +13,7 @@
 #include <arch/cpu.h>
 #include <string.h>
 #include <kernel/vmmcache.h>
+#include <kernel/pipefs.h>
 
 static scache_t *nodecache;
 static tmpfsnode_t *newnode(vfs_t *vfs, int type);
@@ -158,18 +159,28 @@ static int tmpfs_open(vnode_t **nodep, int flag, cred_t *cred) {
 	vnode_t *node = *nodep;
 	tmpfsnode_t *tmpnode = (tmpfsnode_t *)node;
 
+	int error = 0;
 	if (node->type == V_TYPE_CHDEV || node->type == V_TYPE_BLKDEV) {
 		vnode_t *devnode;
-		int err = devfs_getnode(node, tmpnode->attr.rdevmajor, tmpnode->attr.rdevminor, &devnode);
-		if (err)
-			return err;
+		error = devfs_getnode(node, tmpnode->attr.rdevmajor, tmpnode->attr.rdevminor, &devnode);
+		if (error)
+			return error;
 
 		VOP_RELEASE(node);
 		VOP_HOLD(devnode);
 		*nodep = devnode; 
 	}
 
-	return 0;
+	if (node->type == V_TYPE_FIFO) {
+		VOP_LOCK(*nodep);
+		vnode_t *fifo;
+		error = pipefs_getbinding(*nodep, &fifo);
+		VOP_UNLOCK(*nodep);
+		if (error == 0)
+			*nodep = fifo;
+	}
+
+	return error;
 }
 
 static int tmpfs_close(vnode_t *node, int flag, cred_t *cred) {
diff --git a/kernel-src/include/kernel/pipefs.h b/kernel-src/include/kernel/pipefs.h
index 8dc1c106..8902ed08 100644
--- a/kernel-src/include/kernel/pipefs.h
+++ b/kernel-src/include/kernel/pipefs.h
@@ -18,5 +18,6 @@ typedef struct pipenode_t {
 
 void pipefs_init();
 int pipefs_newpipe(vnode_t **nodep);
+int pipefs_getbinding(vnode_t *node, vnode_t **pipep);
 
 #endif
diff --git a/kernel-src/include/kernel/vfs.h b/kernel-src/include/kernel/vfs.h
index 96fd9b74..ce60f419 100644
--- a/kernel-src/include/kernel/vfs.h
+++ b/kernel-src/include/kernel/vfs.h
@@ -78,7 +78,11 @@ typedef struct vnode_t {
 	int type;
 	vfs_t *vfs;
 	vfs_t *vfsmounted;
-	void *socketbinding;
+	union {
+		void *socketbinding;
+		void *fifobinding;
+	};
+
 	struct page_t *pages;
 } vnode_t;