1 files changed, 151 insertions, 16 deletions

diff --git a/sys/kern/kern_descrip.c b/sys/kern/kern_descrip.c
index da10f89..0fb026f 100644
--- a/sys/kern/kern_descrip.c
+++ b/sys/kern/kern_descrip.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2023-2024 Ian Marco Moffett and the Osmora Team.
+ * Copyright (c) 2023-2025 Ian Marco Moffett and the Osmora Team.
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
@@ -31,6 +31,7 @@
 #include <sys/errno.h>
 #include <sys/proc.h>
 #include <sys/limits.h>
+#include <sys/fcntl.h>
 #include <sys/namei.h>
 #include <sys/filedesc.h>
 #include <sys/systm.h>
@@ -135,17 +136,20 @@ fd_close(unsigned int fd)
 }
 
 /*
- * Read bytes from a file using a file
+ * Read/write bytes to/from a file using a file
  * descriptor number.
  *
  * @fd: File descriptor number.
- * @buf: Buffer to read into.
+ * @buf: Buffer with data to read/write
  * @count: Number of bytes to read.
+ * @write: Set to 1 for writes
  */
-int
-fd_read(unsigned int fd, void *buf, size_t count)
+static int
+fd_rw(unsigned int fd, void *buf, size_t count, uint8_t write)
 {
     char *kbuf = NULL;
+    ssize_t n;
+    uint32_t seal;
     struct filedesc *filedes;
     struct sio_txn sio;
     scret_t retval = 0;
@@ -156,8 +160,17 @@ fd_read(unsigned int fd, void *buf, size_t count)
     }
 
     filedes = fd_get(fd);
-    kbuf = dynalloc(count);
+    seal = filedes->flags;
+
+    /* Check the seal */
+    if (write && !ISSET(seal, O_ALLOW_WR)) {
+        return -EPERM;
+    }
+    if (!write && ISSET(seal, O_WRONLY)) {
+        return -EPERM;
+    }
 
+    kbuf = dynalloc(count);
     if (kbuf == NULL) {
         retval = -ENOMEM;
         goto done;
@@ -173,46 +186,111 @@ fd_read(unsigned int fd, void *buf, size_t count)
         goto done;
     }
 
+    /* Check if this violates the file seal */
+    if (!ISSET(filedes->flags, O_ALLOW_WR) && write) {
+        return -EPERM;
+    } else if (ISSET(O_RDONLY, filedes->flags) && write) {
+        return -EPERM;
+    }
+
     sio.len = count;
     sio.buf = kbuf;
     sio.offset = filedes->offset;
 
-    if ((count = vfs_vop_read(filedes->vp, &sio)) < 0) {
-        retval = -EIO;
-        goto done;
-    }
+    spinlock_acquire(&filedes->lock);
+    if (write) {
+        /* Copy in user buffer */
+        if (copyin(buf, kbuf, count) < 0) {
+            retval = -EFAULT;
+            goto done;
+        }
 
-    if (copyout(kbuf, buf, count) < 0) {
-        retval = -EFAULT;
-        goto done;
+        /* Call VFS write hook */
+        if ((n = vfs_vop_write(filedes->vp, &sio)) < 0) {
+            retval = n;
+            goto done;
+        }
+    } else {
+        if ((n = vfs_vop_read(filedes->vp, &sio)) < 0) {
+            retval = n;
+            goto done;
+        }
+
+        /* End of file? */
+        if (n == 0) {
+            retval = 0;
+            goto done;
+        }
+
+        if (copyout(kbuf, buf, count) < 0) {
+            retval = -EFAULT;
+            goto done;
+        }
     }
 
+    /* Increment the offset per read */
+    filedes->offset += n;
     retval = count;
 done:
     if (kbuf != NULL) {
         dynfree(kbuf);
     }
+    spinlock_release(&filedes->lock);
     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)
+{
+    return fd_rw(fd, buf, count, 0);
+}
+
+int
+fd_write(unsigned int fd, void *buf, size_t count)
+{
+    return fd_rw(fd, buf, count, 1);
+}
+
 /*
  * Open a file and get a file descriptor
  * number.
  *
  * @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;
@@ -223,7 +301,16 @@ 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;
 }
 
@@ -249,3 +336,51 @@ fd_dup(int fd)
     new_desc->vp = tmp->vp;
     return new_desc->fdno;
 }
+
+off_t
+fd_seek(int fildes, off_t offset, int whence)
+{
+    struct filedesc *tmp;
+    struct vattr attr;
+    struct vop_getattr_args getattr_args;
+
+    tmp = fd_get(fildes);
+    if (tmp == NULL) {
+        return -EBADF;
+    }
+
+    getattr_args.vp = tmp->vp;
+    getattr_args.res = &attr;
+    if ((vfs_vop_getattr(tmp->vp, &getattr_args)) < 0) {
+        return -EPIPE;
+    }
+
+    switch (whence) {
+    case SEEK_SET:
+        tmp->offset = offset;
+        break;
+    case SEEK_CUR:
+        tmp->offset += offset;
+        break;
+    case SEEK_END:
+        tmp->offset = attr.size + offset;
+        break;
+    default:
+        return -EINVAL;
+    }
+
+    return tmp->offset;
+}
+
+/*
+ * Update file offset
+ *
+ * arg0: `filedes'
+ * arg1: `offset'
+ * arg2: `whence'
+ */
+scret_t
+sys_lseek(struct syscall_args *scargs)
+{
+    return fd_seek(scargs->arg0, scargs->arg1, scargs->arg2);
+}