From caad8d9443d1e751ba743de660cc1d592faae5d9 Mon Sep 17 00:00:00 2001
From: Ian Moffett <ian@osmora.org>
Date: Mon, 9 Sep 2024 14:12:10 -0400
Subject: kernel: vfs: Refactor fd related code

Signed-off-by: Ian Moffett <ian@osmora.org>
---
 sys/kern/vfs_syscalls.c | 181 ++----------------------------------------------
 1 file changed, 4 insertions(+), 177 deletions(-)

(limited to 'sys/kern/vfs_syscalls.c')

diff --git a/sys/kern/vfs_syscalls.c b/sys/kern/vfs_syscalls.c
index 77070ab..f4c5c59 100644
--- a/sys/kern/vfs_syscalls.c
+++ b/sys/kern/vfs_syscalls.c
@@ -28,82 +28,10 @@
  */
 
 #include <sys/vfs.h>
-#include <sys/vnode.h>
 #include <sys/types.h>
-#include <sys/systm.h>
-#include <sys/errno.h>
-#include <sys/sio.h>
 #include <sys/filedesc.h>
-#include <sys/atomic.h>
-#include <sys/namei.h>
-#include <sys/proc.h>
-#include <sys/limits.h>
-#include <sys/syslog.h>
-#include <vm/dynalloc.h>
-#include <assert.h>
 #include <string.h>
 
-/*
- * Fetch a file descriptor from a file descriptor
- * number.
- *
- * @fdno: File descriptor to fetch
- */
-static struct filedesc *
-fd_get(int fdno)
-{
-    struct proc *td = this_td();
-
-    if (fdno < 0 || fdno > PROC_MAX_FILEDES) {
-        return NULL;
-    }
-
-    return td->fds[fdno];
-}
-
-/*
- * Allocate a file descriptor.
- *
- * @fd_out: Pointer to allocated file descriptor output.
- *
- * This routine will create a new file descriptor
- * table entry.
- *
- * Returns 0 on success.
- */
-static int
-fd_alloc(struct filedesc **fd_out)
-{
-    struct filedesc *fd;
-    struct proc *td = this_td();
-
-    /* Find free fd table entry */
-    for (size_t i = 3; i < PROC_MAX_FILEDES; ++i) {
-        if (td->fds[i] != NULL) {
-            /* In use */
-            continue;
-        }
-
-        fd = dynalloc(sizeof(struct filedesc));
-        memset(fd, 0, sizeof(struct filedesc));
-
-        if (fd == NULL) {
-            return -ENOMEM;
-        }
-
-        fd->refcnt = 1;
-        fd->fdno = i;
-        td->fds[i] = fd;
-
-        if (fd_out != NULL)
-            *fd_out = fd;
-
-        return 0;
-    }
-
-    return -EMFILE;
-}
-
 /*
  * arg0: pathname
  * arg1: oflags
@@ -113,31 +41,7 @@ fd_alloc(struct filedesc **fd_out)
 scret_t
 sys_open(struct syscall_args *scargs)
 {
-    int error;
-    const char *pathname;
-    char pathbuf[PATH_MAX];
-    struct filedesc *filedes;
-    struct nameidata nd;
-
-    pathname = (char *)scargs->arg0;
-    nd.path = pathbuf;
-    nd.flags = 0;
-
-    if (copyinstr(pathname, pathbuf, PATH_MAX) < 0) {
-        return -EFAULT;
-    }
-
-    if ((error = namei(&nd)) < 0) {
-        return error;
-    }
-
-    if ((error = fd_alloc(&filedes)) != 0) {
-        vfs_release_vnode(nd.vp);
-        return error;
-    }
-
-    filedes->vp = nd.vp;
-    return filedes->fdno;
+    return fd_open((char *)scargs->arg0, scargs->arg1);
 }
 
 /*
@@ -146,32 +50,7 @@ sys_open(struct syscall_args *scargs)
 scret_t
 sys_close(struct syscall_args *args)
 {
-    struct filedesc *filedes;
-    struct proc *td;
-    int fd = args->arg0;
-
-    if ((filedes = fd_get(fd)) == NULL) {
-        return -EBADF;
-    }
-
-    /* Return if other threads still hold a ref */
-    if (atomic_dec_int(&filedes->refcnt) > 0) {
-        return 0;
-    }
-
-    td = this_td();
-
-    /*
-     * Each file descriptor structure references a vnode,
-     * we want to reclaim it or at the very least drop
-     * one of its references. After we've cleaned up within
-     * the file descriptor, we can clear it from the fd table
-     * and free up the memory for it.
-     */
-    vfs_release_vnode(filedes->vp);
-    td->fds[fd] = NULL;
-    dynfree(filedes);
-    return 0;
+    return fd_close(args->arg0);
 }
 
 /*
@@ -182,58 +61,6 @@ sys_close(struct syscall_args *args)
 scret_t
 sys_read(struct syscall_args *scargs)
 {
-    int fd;
-    char *buf, *kbuf = NULL;
-    size_t count;
-    struct filedesc *filedes;
-    struct sio_txn sio;
-    scret_t retval = 0;
-
-    fd = scargs->arg0;
-    buf = (char *)scargs->arg1;
-    count = scargs->arg2;
-
-    if (count > SSIZE_MAX) {
-        retval = -EINVAL;
-        goto done;
-    }
-
-    filedes = fd_get(fd);
-    kbuf = dynalloc(count);
-
-    if (kbuf == NULL) {
-        retval = -ENOMEM;
-        goto done;
-    }
-
-    if (filedes == NULL) {
-        retval = -EBADF;
-        goto done;
-    }
-
-    if (filedes->is_dir) {
-        retval = -EISDIR;
-        goto done;
-    }
-
-    sio.len = count;
-    sio.buf = kbuf;
-    sio.offset = filedes->offset;
-
-    if ((count = vfs_vop_read(filedes->vp, &sio)) < 0) {
-        retval = -EIO;
-        goto done;
-    }
-
-    if (copyout(kbuf, buf, count) < 0) {
-        retval = -EFAULT;
-        goto done;
-    }
-
-    retval = count;
-done:
-    if (kbuf != NULL) {
-        dynfree(kbuf);
-    }
-    return retval;
+    return fd_read(scargs->arg0, (void *)scargs->arg1,
+        scargs->arg2);
 }
-- 
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