u-boot/fs/semihostingfs.c
Sean Anderson f676b45151 fs: Add semihosting filesystem
This adds a filesystem which is backed by the host's filesystem. It is
modeled off of sandboxfs, which has very similar aims. Semihosting
doesn't support listing directories (except with SYS_SYSTEM), so neither
do we. it's possible to optimize a bit for the common case of reading a
whole file by omitting a call to smh_seek, but this is left as a future
optimization.

Signed-off-by: Sean Anderson <sean.anderson@seco.com>
2022-04-01 15:03:13 -04:00

115 lines
2.1 KiB
C

// SPDX-License-Identifier: GPL-2.0+
/*
* Copyright (C) 2022, Sean Anderson <sean.anderson@seco.com>
* Copyright (c) 2012, Google Inc.
*/
#include <common.h>
#include <fs.h>
#include <malloc.h>
#include <os.h>
#include <semihosting.h>
#include <semihostingfs.h>
int smh_fs_set_blk_dev(struct blk_desc *rbdd, struct disk_partition *info)
{
/*
* Only accept a NULL struct blk_desc for the semihosting, which is when
* hostfs interface is used
*/
return !!rbdd;
}
static int smh_fs_read_at(const char *filename, loff_t pos, void *buffer,
loff_t maxsize, loff_t *actread)
{
long fd, size, ret;
fd = smh_open(filename, MODE_READ | MODE_BINARY);
if (fd < 0)
return fd;
ret = smh_seek(fd, pos);
if (ret < 0) {
smh_close(fd);
return ret;
}
if (!maxsize) {
size = smh_flen(fd);
if (ret < 0) {
smh_close(fd);
return size;
}
maxsize = size;
}
size = smh_read(fd, buffer, maxsize);
smh_close(fd);
if (size < 0)
return size;
*actread = size;
return 0;
}
static int smh_fs_write_at(const char *filename, loff_t pos, void *buffer,
loff_t towrite, loff_t *actwrite)
{
long fd, size, ret;
fd = smh_open(filename, MODE_READ | MODE_BINARY | MODE_PLUS);
if (fd < 0)
return fd;
ret = smh_seek(fd, pos);
if (ret < 0) {
smh_close(fd);
return ret;
}
ret = smh_write(fd, buffer, towrite, &size);
smh_close(fd);
*actwrite = size;
return ret;
}
int smh_fs_size(const char *filename, loff_t *result)
{
long fd, size;
fd = smh_open(filename, MODE_READ | MODE_BINARY);
if (fd < 0)
return fd;
size = smh_flen(fd);
smh_close(fd);
if (size < 0)
return size;
*result = size;
return 0;
}
int smh_fs_read(const char *filename, void *buf, loff_t offset, loff_t len,
loff_t *actread)
{
int ret;
ret = smh_fs_read_at(filename, offset, buf, len, actread);
if (ret)
printf("** Unable to read file %s **\n", filename);
return ret;
}
int smh_fs_write(const char *filename, void *buf, loff_t offset,
loff_t len, loff_t *actwrite)
{
int ret;
ret = smh_fs_write_at(filename, offset, buf, len, actwrite);
if (ret)
printf("** Unable to write file %s **\n", filename);
return ret;
}