diff options
Diffstat (limited to 'sys/kern/kern_descrip.c')
| -rw-r--r-- | sys/kern/kern_descrip.c | 233 |
1 files changed, 233 insertions, 0 deletions
diff --git a/sys/kern/kern_descrip.c b/sys/kern/kern_descrip.c new file mode 100644 index 0000000..adc5027 --- /dev/null +++ b/sys/kern/kern_descrip.c @@ -0,0 +1,233 @@ +/* + * Copyright (c) 2023-2024 Ian Marco Moffett and the Osmora Team. + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions are met: + * + * 1. Redistributions of source code must retain the above copyright notice, + * this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * 3. Neither the name of Hyra nor the names of its + * contributors may be used to endorse or promote products derived from + * this software without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" + * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE + * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR + * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF + * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS + * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN + * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) + * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE + * POSSIBILITY OF SUCH DAMAGE. + */ + +#include <sys/atomic.h> +#include <sys/errno.h> +#include <sys/proc.h> +#include <sys/limits.h> +#include <sys/namei.h> +#include <sys/filedesc.h> +#include <sys/systm.h> +#include <vm/dynalloc.h> +#include <string.h> + +/* + * 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. + */ +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; +} + +/* + * Fetch a file descriptor from a file descriptor + * number. + * + * @fdno: File descriptor to fetch + */ +struct filedesc * +fd_get(unsigned int fdno) +{ + struct proc *td = this_td(); + + if (fdno > PROC_MAX_FILEDES) { + return NULL; + } + + return td->fds[fdno]; +} + +/* + * Close a file descriptor with a file + * descriptor number. + * + * @fd: File descriptor number to close. + */ +int +fd_close(unsigned int fd) +{ + struct filedesc *filedes; + struct proc *td; + + 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; +} + +/* + * Read bytes from a file using a file + * descriptor number. + * + * @fd: File descriptor number. + * @buf: Buffer to read into. + * @count: Number of bytes to read. + */ +int +fd_read(unsigned int fd, void *buf, size_t count) +{ + char *kbuf = NULL; + struct filedesc *filedes; + struct sio_txn sio; + scret_t retval = 0; + + 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; +} + +/* + * 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; + char pathbuf[PATH_MAX]; + struct filedesc *filedes; + struct nameidata nd; + + 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; +} |