Enrico Fraccaroli
94 lines
2.2 KiB
C
94 lines
2.2 KiB
C
/// MentOS, The Mentoring Operating system project
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/// @file open.c
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/// @brief
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/// @copyright (c) 2014-2021 This file is distributed under the MIT License.
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/// See LICENSE.md for details.
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#include "process/scheduler.h"
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#include "process/process.h"
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#include "system/printk.h"
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#include "fcntl.h"
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#include "system/syscall.h"
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#include "string.h"
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#include "limits.h"
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#include "io/debug.h"
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#include "sys/errno.h"
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#include "stdio.h"
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#include "fs/vfs.h"
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int sys_open(const char *pathname, int flags, mode_t mode)
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{
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// Get the current task.
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task_struct *task = scheduler_get_current_process();
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// Search for an unused fd.
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int fd;
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for (fd = 0; fd < task->max_fd; ++fd) {
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if (!task->fd_list[fd].file_struct) {
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break;
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}
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}
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// Check if there is not fd available.
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if (fd >= MAX_OPEN_FD) {
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return -EMFILE;
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}
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// If fd limit is reached, try to allocate more
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if (fd == task->max_fd) {
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if (!vfs_extend_task_fd_list(task)) {
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pr_err("Failed to extend the file descriptor list.\n");
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return -EMFILE;
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}
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}
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// Try to open the file.
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vfs_file_t *file = vfs_open(pathname, flags, mode);
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if (file == NULL) {
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return -errno;
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}
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// Set the file descriptor id.
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task->fd_list[fd].file_struct = file;
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if (!bitmask_check(flags, O_APPEND)) {
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// Reset the offset.
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task->fd_list[fd].file_struct->f_pos = 0;
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} else {
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stat_t stat;
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// Stat the file.
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file->fs_operations->stat_f(file, &stat);
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// Point at the last character
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task->fd_list[fd].file_struct->f_pos = stat.st_size;
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}
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// Set the flags.
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task->fd_list[fd].flags_mask = flags;
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// Return the file descriptor and increment it.
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return fd;
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}
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int sys_close(int fd)
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{
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// Get the current task.
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task_struct *task = scheduler_get_current_process();
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// Check the current FD.
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if (fd < 0 || fd >= task->max_fd) {
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return -EMFILE;
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}
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// Get the file.
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vfs_file_t *file = task->fd_list[fd].file_struct;
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if (file == NULL) {
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return -1;
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}
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// Remove the reference to the file.
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task->fd_list[fd].file_struct = NULL;
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// Call the close function.
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return vfs_close(file);
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}
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