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- /* Copyright (C) 2014 Stony Brook University
- This file is part of Graphene Library OS.
- Graphene Library OS is free software: you can redistribute it and/or
- modify it under the terms of the GNU Lesser General Public License
- as published by the Free Software Foundation, either version 3 of the
- License, or (at your option) any later version.
- Graphene Library OS is distributed in the hope that it will be useful,
- but WITHOUT ANY WARRANTY; without even the implied warranty of
- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- GNU Lesser General Public License for more details.
- You should have received a copy of the GNU Lesser General Public License
- along with this program. If not, see <http://www.gnu.org/licenses/>. */
- /*
- * fs.c
- *
- * This file contains codes for implementation of 'str' filesystem.
- */
- #include <asm/fcntl.h>
- #include <asm/mman.h>
- #include <asm/prctl.h>
- #include <asm/unistd.h>
- #include <errno.h>
- #include <linux/fcntl.h>
- #include <linux/stat.h>
- #include <pal.h>
- #include <pal_error.h>
- #include <shim_fs.h>
- #include <shim_internal.h>
- #include <shim_profile.h>
- int str_open(struct shim_handle* hdl, struct shim_dentry* dent, int flags) {
- struct shim_str_data* data = dent->data;
- /* when str file is opened, it must have a data */
- if (!dent->data)
- return -ENOENT;
- REF_INC(data->ref_count);
- hdl->dentry = dent;
- hdl->flags = flags;
- return 0;
- }
- int str_dput(struct shim_dentry* dent) {
- struct shim_str_data* data = dent->data;
- if (!data || REF_DEC(data->ref_count) > 1)
- return 0;
- if (data->str) {
- free(data->str);
- data->str = NULL;
- }
- data->len = 0;
- data->buf_size = 0;
- free(dent->data);
- dent->data = NULL;
- return 0;
- }
- int str_close(struct shim_handle* hdl) {
- if (hdl->flags & (O_WRONLY | O_RDWR)) {
- int ret = str_flush(hdl);
- if (ret < 0)
- return ret;
- }
- str_dput(hdl->dentry);
- return 0;
- }
- ssize_t str_read(struct shim_handle* hdl, void* buf, size_t count) {
- ssize_t ret = 0;
- if (!(hdl->acc_mode & MAY_READ)) {
- ret = -EACCES;
- goto out;
- }
- struct shim_str_handle* strhdl = &hdl->info.str;
- assert(hdl->dentry);
- assert(strhdl->data);
- struct shim_str_data* data = strhdl->data;
- if (!data->str) {
- debug("str_data has no str\n");
- ret = -EACCES;
- goto out;
- }
- if (!strhdl->ptr)
- strhdl->ptr = data->str;
- off_t offset = strhdl->ptr - data->str;
- size_t remain = data->len - offset;
- if (count >= remain) {
- memcpy(buf, strhdl->ptr, remain);
- strhdl->ptr += remain;
- ret = remain;
- goto out;
- }
- memcpy(buf, strhdl->ptr, count);
- strhdl->ptr += count;
- ret = count;
- out:
- return ret;
- }
- ssize_t str_write(struct shim_handle* hdl, const void* buf, size_t count) {
- if (!(hdl->acc_mode & MAY_WRITE))
- return -EACCES;
- struct shim_str_handle* strhdl = &hdl->info.str;
- assert(hdl->dentry);
- assert(strhdl->data);
- struct shim_str_data* data = strhdl->data;
- if (!data->str || strhdl->ptr + count > data->str + data->buf_size) {
- int newlen = 0;
- if (data->str) {
- newlen = data->buf_size * 2;
- while (strhdl->ptr + count > data->str + newlen) {
- newlen *= 2;
- }
- } else {
- newlen = count;
- }
- char* newbuf = malloc(newlen);
- if (!newbuf)
- return -ENOMEM;
- if (data->str) {
- memcpy(newbuf, data->str, data->len);
- free(data->str);
- }
- strhdl->ptr = newbuf + (strhdl->ptr - data->str);
- data->str = newbuf;
- data->buf_size = newlen;
- }
- memcpy(strhdl->ptr, buf, count);
- strhdl->ptr += count;
- data->dirty = true;
- if (strhdl->ptr >= data->str + data->len)
- data->len = strhdl->ptr - data->str;
- return count;
- }
- off_t str_seek(struct shim_handle* hdl, off_t offset, int whence) {
- struct shim_str_handle* strhdl = &hdl->info.str;
- assert(hdl->dentry);
- assert(strhdl->data);
- struct shim_str_data* data = strhdl->data;
- switch (whence) {
- case SEEK_SET:
- if (offset < 0)
- return -EINVAL;
- strhdl->ptr = data->str;
- if (strhdl->ptr > data->str + data->len)
- strhdl->ptr = data->str + data->len;
- break;
- case SEEK_CUR:
- if (offset >= 0) {
- strhdl->ptr += offset;
- if (strhdl->ptr > data->str + data->len)
- strhdl->ptr = data->str + data->len;
- } else {
- strhdl->ptr -= offset;
- if (strhdl->ptr < data->str)
- strhdl->ptr = data->str;
- }
- break;
- case SEEK_END:
- if (offset < 0)
- return -EINVAL;
- strhdl->ptr = data->str + data->len - offset;
- if (strhdl->ptr < data->str)
- strhdl->ptr = data->str;
- break;
- }
- return strhdl->ptr - data->str;
- }
- int str_flush(struct shim_handle* hdl) {
- struct shim_str_handle* strhdl = &hdl->info.str;
- assert(hdl->dentry);
- assert(strhdl->data);
- struct shim_str_data* data = strhdl->data;
- if (!data->dirty)
- return 0;
- if (!data->modify)
- return -EACCES;
- return data->modify(hdl);
- }
- struct shim_fs_ops str_fs_ops = {
- .close = &str_close,
- .read = &str_read,
- .write = &str_write,
- .seek = &str_seek,
- .flush = &str_flush,
- };
- struct shim_d_ops str_d_ops = {
- .open = &str_open,
- .dput = &str_dput,
- };
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