blob: 5866ad020bba1a58c3a71c38f929930834e2ddb4 [file] [log] [blame]
/*
* Copyright (c) 2018 Linaro Limited
*
* SPDX-License-Identifier: Apache-2.0
*/
/**
* @file
* @brief File descriptor table
*
* This file provides generic file descriptor table implementation, suitable
* for any I/O object implementing POSIX I/O semantics (i.e. read/write +
* aux operations).
*/
#include <errno.h>
#include <fcntl.h>
#include <kernel.h>
#include <misc/fdtable.h>
struct fd_entry {
void *obj;
const struct fd_op_vtable *vtable;
};
/* A few magic values for fd_entry::obj used in the code. */
#define FD_OBJ_RESERVED (void *)1
#define FD_OBJ_STDIN (void *)0x10
#define FD_OBJ_STDOUT (void *)0x11
#define FD_OBJ_STDERR (void *)0x12
#ifdef CONFIG_POSIX_API
static const struct fd_op_vtable stdinout_fd_op_vtable;
#endif
static struct fd_entry fdtable[CONFIG_POSIX_MAX_FDS] = {
#ifdef CONFIG_POSIX_API
/*
* Predefine entries for stdin/stdout/stderr. Object pointer
* is unused and just should be !0 (random different values
* are used to posisbly help with debugging).
*/
{FD_OBJ_STDIN, &stdinout_fd_op_vtable},
{FD_OBJ_STDOUT, &stdinout_fd_op_vtable},
{FD_OBJ_STDERR, &stdinout_fd_op_vtable},
#endif
};
static K_MUTEX_DEFINE(fdtable_lock);
static int _find_fd_entry(void)
{
int fd;
for (fd = 0; fd < ARRAY_SIZE(fdtable); fd++) {
if (fdtable[fd].obj == NULL) {
return fd;
}
}
errno = ENFILE;
return -1;
}
static int _check_fd(int fd)
{
if (fd < 0 || fd >= ARRAY_SIZE(fdtable) || fdtable[fd].obj == NULL) {
errno = EBADF;
return -1;
}
return 0;
}
void *z_get_fd_obj(int fd, const struct fd_op_vtable *vtable, int err)
{
struct fd_entry *fd_entry;
if (_check_fd(fd) < 0) {
return NULL;
}
fd_entry = &fdtable[fd];
if (vtable != NULL && fd_entry->vtable != vtable) {
errno = err;
return NULL;
}
return fd_entry->obj;
}
void *z_get_fd_obj_and_vtable(int fd, const struct fd_op_vtable **vtable)
{
struct fd_entry *fd_entry;
if (_check_fd(fd) < 0) {
return NULL;
}
fd_entry = &fdtable[fd];
*vtable = fd_entry->vtable;
return fd_entry->obj;
}
int z_reserve_fd(void)
{
int fd;
(void)k_mutex_lock(&fdtable_lock, K_FOREVER);
fd = _find_fd_entry();
if (fd >= 0) {
/* Mark entry as used, z_finalize_fd() will fill it in. */
fdtable[fd].obj = FD_OBJ_RESERVED;
}
k_mutex_unlock(&fdtable_lock);
return fd;
}
void z_finalize_fd(int fd, void *obj, const struct fd_op_vtable *vtable)
{
/* Assumes fd was already bounds-checked. */
fdtable[fd].obj = obj;
fdtable[fd].vtable = vtable;
}
void z_free_fd(int fd)
{
/* Assumes fd was already bounds-checked. */
fdtable[fd].obj = NULL;
}
int z_alloc_fd(void *obj, const struct fd_op_vtable *vtable)
{
int fd;
fd = z_reserve_fd();
if (fd >= 0) {
z_finalize_fd(fd, obj, vtable);
}
return fd;
}
#ifdef CONFIG_POSIX_API
ssize_t read(int fd, void *buf, size_t sz)
{
if (_check_fd(fd) < 0) {
return -1;
}
return fdtable[fd].vtable->read(fdtable[fd].obj, buf, sz);
}
ssize_t write(int fd, const void *buf, size_t sz)
{
if (_check_fd(fd) < 0) {
return -1;
}
return fdtable[fd].vtable->write(fdtable[fd].obj, buf, sz);
}
int close(int fd)
{
int res;
if (_check_fd(fd) < 0) {
return -1;
}
res = z_fdtable_call_ioctl(fdtable[fd].vtable, fdtable[fd].obj, ZFD_IOCTL_CLOSE);
z_free_fd(fd);
return res;
}
int fsync(int fd)
{
if (_check_fd(fd) < 0) {
return -1;
}
return z_fdtable_call_ioctl(fdtable[fd].vtable, fdtable[fd].obj, ZFD_IOCTL_FSYNC);
}
off_t lseek(int fd, off_t offset, int whence)
{
if (_check_fd(fd) < 0) {
return -1;
}
return z_fdtable_call_ioctl(fdtable[fd].vtable, fdtable[fd].obj, ZFD_IOCTL_LSEEK,
offset, whence);
}
int ioctl(int fd, unsigned long request, ...)
{
va_list args;
int res;
if (_check_fd(fd) < 0) {
return -1;
}
va_start(args, request);
res = fdtable[fd].vtable->ioctl(fdtable[fd].obj, request, args);
va_end(args);
return res;
}
int fcntl(int fd, int cmd, ...)
{
va_list args;
int res;
if (_check_fd(fd) < 0) {
return -1;
}
/* Handle fdtable commands. */
switch (cmd) {
case F_DUPFD:
/* Not implemented so far. */
errno = EINVAL;
return -1;
}
/* The rest of commands are per-fd, handled by ioctl vmethod. */
va_start(args, cmd);
res = fdtable[fd].vtable->ioctl(fdtable[fd].obj, cmd, args);
va_end(args);
return res;
}
/*
* fd operations for stdio/stdout/stderr
*/
int _impl__zephyr_write(const char *buf, int nbytes);
static ssize_t stdinout_read_vmeth(void *obj, void *buffer, size_t count)
{
return 0;
}
static ssize_t stdinout_write_vmeth(void *obj, const void *buffer, size_t count)
{
#if defined(CONFIG_BOARD_NATIVE_POSIX)
return write(1, buffer, count);
#elif defined(CONFIG_NEWLIB_LIBC)
return _impl__zephyr_write(buffer, count);
#else
return 0;
#endif
}
static int stdinout_ioctl_vmeth(void *obj, unsigned int request, va_list args)
{
errno = EINVAL;
return -1;
}
static const struct fd_op_vtable stdinout_fd_op_vtable = {
.read = stdinout_read_vmeth,
.write = stdinout_write_vmeth,
.ioctl = stdinout_ioctl_vmeth,
};
#endif /* CONFIG_POSIX_API */