kernel: vfs: Add support for O_CREAT flag

Add support for the O_CREAT flag which allows file creation upon an
open() call.

Signed-off-by: Ian Moffett <ian@osmora.org>

6 files changed, 48 insertions, 6 deletions

diff --git a/sys/fs/ctlfs.c b/sys/fs/ctlfs.c
index 64d3a1a..9225114 100644
--- a/sys/fs/ctlfs.c
+++ b/sys/fs/ctlfs.c
@@ -380,7 +380,8 @@ static const struct vops ctlfs_vops = {
     .read = ctlfs_read,
     .getattr = NULL,
     .write = NULL,
-    .reclaim = ctlfs_reclaim
+    .reclaim = ctlfs_reclaim,
+    .create = NULL
 };
 
 const struct vfsops g_ctlfs_vfsops = {
diff --git a/sys/fs/devfs.c b/sys/fs/devfs.c
index 0c087f0..293ee0a 100644
--- a/sys/fs/devfs.c
+++ b/sys/fs/devfs.c
@@ -273,7 +273,8 @@ const struct vops g_devfs_vops = {
     .reclaim = devfs_reclaim,
     .read = devfs_read,
     .write = devfs_write,
-    .getattr = devfs_getattr
+    .getattr = devfs_getattr,
+    .create = NULL
 };
 
 const struct vfsops g_devfs_vfsops = {
diff --git a/sys/fs/initramfs.c b/sys/fs/initramfs.c
index c3f9b14..c41deb4 100644
--- a/sys/fs/initramfs.c
+++ b/sys/fs/initramfs.c
@@ -279,7 +279,8 @@ const struct vops g_initramfs_vops = {
     .read = initramfs_read,
     .write = NULL,
     .reclaim = initramfs_reclaim,
-    .getattr = initramfs_getattr
+    .getattr = initramfs_getattr,
+    .create = NULL,
 };
 
 const struct vfsops g_initramfs_vfsops = {
diff --git a/sys/include/sys/fcntl.h b/sys/include/sys/fcntl.h
index 122a378..83d38af 100644
--- a/sys/include/sys/fcntl.h
+++ b/sys/include/sys/fcntl.h
@@ -33,6 +33,7 @@
 #define O_RDONLY    0x0000
 #define O_WRONLY    0x0001
 #define O_RDWR      0x0002
+#define O_CREAT     0x0004
 
 /* Makes seal checking easier */
 #if defined(_KERNEL)
diff --git a/sys/include/sys/vnode.h b/sys/include/sys/vnode.h
index cd71817..1a6b2aa 100644
--- a/sys/include/sys/vnode.h
+++ b/sys/include/sys/vnode.h
@@ -86,6 +86,13 @@ struct vop_lookup_args {
     struct vnode **vpp;     /* Result vnode */
 };
 
+struct vop_create_args {
+    const char *path;       /* Full path */
+    const char *ppath;      /* Parent path */
+    struct vnode *dirvp;    /* Directory vnode */
+    struct vnode **vpp;     /* Result vnode */
+};
+
 /*
  * A field in this structure is unavailable
  * if it has a value of VNOVAL.
@@ -106,6 +113,7 @@ struct vops {
     int(*read)(struct vnode *vp, struct sio_txn *sio);
     int(*write)(struct vnode *vp, struct sio_txn *sio);
     int(*reclaim)(struct vnode *vp);
+    int(*create)(struct vop_create_args *args);
 };
 
 extern struct vnode *g_root_vnode;
diff --git a/sys/kern/kern_descrip.c b/sys/kern/kern_descrip.c
index a2dd667..da67530 100644
--- a/sys/kern/kern_descrip.c
+++ b/sys/kern/kern_descrip.c
@@ -229,6 +229,29 @@ done:
     return retval;
 }
 
+static int
+fd_do_create(const char *path, struct nameidata *ndp)
+{
+    struct vop_create_args cargs;
+    struct vnode *dirvp = ndp->vp;
+    const struct vops *vops = dirvp->vops;
+    int error;
+
+    if (vops->create == NULL) {
+        return -EINVAL;
+    }
+
+    cargs.path = path;
+    cargs.ppath = ndp->path;
+    cargs.dirvp = dirvp;
+    cargs.vpp = &ndp->vp;
+    if ((error = vops->create(&cargs)) < 0) {
+        return error;
+    }
+
+    return 0;
+}
+
 int
 fd_read(unsigned int fd, void *buf, size_t count)
 {
@@ -247,18 +270,17 @@ fd_write(unsigned int fd, void *buf, size_t count)
  *
  * @pathname: Path of file to open.
  * @flags: Flags to use.
- *
- * TODO: Use of flags.
  */
 int
 fd_open(const char *pathname, int flags)
 {
     int error;
+    const struct vops *vops;
     struct filedesc *filedes;
     struct nameidata nd;
 
     nd.path = pathname;
-    nd.flags = 0;
+    nd.flags = ISSET(flags, O_CREAT) ? NAMEI_WANTPARENT : 0;
 
     if ((error = namei(&nd)) < 0) {
         return error;
@@ -269,6 +291,14 @@ fd_open(const char *pathname, int flags)
         return error;
     }
 
+    vops = nd.vp->vops;
+    if (ISSET(flags, O_CREAT) && vops->create != NULL) {
+        error = fd_do_create(pathname, &nd);
+    }
+    if (error < 0) {
+        return error;
+    }
+
     filedes->vp = nd.vp;
     filedes->flags = flags;
     return filedes->fdno;