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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 'proc' filesystem.
- */
- #define __KERNEL__
- #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_handle.h>
- #include <shim_internal.h>
- #include <shim_thread.h>
- #include <shim_utils.h>
- extern const struct proc_nm_ops nm_thread;
- extern const struct proc_fs_ops fs_thread;
- extern const struct proc_dir dir_thread;
- extern const struct proc_nm_ops nm_ipc_thread;
- extern const struct proc_fs_ops fs_ipc_thread;
- extern const struct proc_dir dir_ipc_thread;
- extern const struct proc_fs_ops fs_meminfo;
- extern const struct proc_fs_ops fs_cpuinfo;
- const struct proc_dir proc_root = {
- .size = 5,
- .ent =
- {
- {
- .name = "self",
- .fs_ops = &fs_thread,
- .dir = &dir_thread,
- },
- {
- .nm_ops = &nm_thread,
- .fs_ops = &fs_thread,
- .dir = &dir_thread,
- },
- {
- .nm_ops = &nm_ipc_thread,
- .fs_ops = &fs_ipc_thread,
- .dir = &dir_ipc_thread,
- },
- {
- .name = "meminfo",
- .fs_ops = &fs_meminfo,
- },
- {
- .name = "cpuinfo",
- .fs_ops = &fs_cpuinfo,
- },
- },
- };
- #define PROC_INO_BASE 1
- static int proc_root_mode(const char* name, mode_t* mode) {
- __UNUSED(name); // We know this is /proc
- *mode = 0555;
- return 0;
- }
- static int proc_root_stat(const char* name, struct stat* buf) {
- __UNUSED(name); // We know this is /proc
- memset(buf, 0, sizeof(struct stat));
- buf->st_dev = buf->st_ino = 1;
- buf->st_mode = 0555 | S_IFDIR;
- buf->st_uid = 0;
- buf->st_gid = 0;
- buf->st_size = 4096;
- return 0;
- }
- static int proc_root_open(struct shim_handle* hdl, const char* name, int flags) {
- __UNUSED(hdl); // this is a placeholder function
- __UNUSED(name); // We know this is /proc
- if (flags & (O_WRONLY | O_RDWR))
- return -EISDIR;
- // Don't really need to do any work here, but keeping as a placeholder,
- // just in case.
- return 0;
- }
- struct proc_fs_ops fs_proc_root = {
- .open = &proc_root_open,
- .mode = &proc_root_mode,
- .stat = &proc_root_stat,
- };
- const struct proc_ent proc_root_ent = {
- .name = "",
- .fs_ops = &fs_proc_root,
- .dir = &proc_root,
- };
- static inline int token_len(const char* str, const char** next_str) {
- const char* t = str;
- while (*t && *t != '/') {
- t++;
- }
- if (next_str)
- *next_str = *t ? t + 1 : NULL;
- return t - str;
- }
- static int proc_match_name(const char* trim_name, const struct proc_ent** found_ent) {
- if (!trim_name || !trim_name[0]) {
- *found_ent = &proc_root_ent;
- return 0;
- }
- const char* token = trim_name;
- const char* next_token = NULL;
- const struct proc_dir* dir = &proc_root;
- const struct proc_ent* ent = NULL;
- if (*token == '/')
- token++;
- while (token) {
- int tlen = token_len(token, &next_token);
- for (ent = dir->ent; ent < dir->ent + dir->size; ent++) {
- if (ent->name && !memcmp(ent->name, token, tlen))
- break;
- if (ent->nm_ops && ent->nm_ops->match_name && ent->nm_ops->match_name(trim_name))
- break;
- }
- if (ent == dir->ent + dir->size) {
- /* couldn't find any entry corresponding to token */
- return -ENOENT;
- }
- if (!next_token) {
- /* found the entry, break out of the while loop */
- break;
- }
- if (!ent->dir) {
- /* still have tokens left, but current entry doesn't have subdirs/files */
- return -ENOENT;
- }
- dir = ent->dir;
- token = next_token;
- }
- *found_ent = ent;
- return 0;
- }
- static int proc_mode(struct shim_dentry* dent, mode_t* mode) {
- if (qstrempty(&dent->rel_path)) {
- dent->ino = PROC_INO_BASE;
- *mode = 0555 | S_IFDIR;
- return 0;
- }
- /* don't care about forced or not */
- const char* rel_path = qstrgetstr(&dent->rel_path);
- const struct proc_ent* ent;
- int ret = proc_match_name(rel_path, &ent);
- if (ret < 0)
- return ret;
- if (!ent->fs_ops || !ent->fs_ops->mode)
- return -EACCES;
- return ent->fs_ops->mode(rel_path, mode);
- }
- static int proc_lookup(struct shim_dentry* dent) {
- if (qstrempty(&dent->rel_path)) {
- dent->ino = PROC_INO_BASE;
- dent->state |= DENTRY_ISDIRECTORY;
- return 0;
- }
- /* don't care about forced or not */
- const struct proc_ent* ent = NULL;
- int ret = proc_match_name(qstrgetstr(&dent->rel_path), &ent);
- if (!ret && ent->dir)
- dent->state |= DENTRY_ISDIRECTORY;
- if (ent && ent->fs_ops && ent->fs_ops->follow_link)
- dent->state |= DENTRY_ISLINK;
- return ret;
- }
- static int proc_mount(const char* uri, void** mount_data) {
- // Arguments for compatibility with other FSes
- __UNUSED(uri);
- __UNUSED(mount_data);
- /* do nothing */
- return 0;
- }
- static int proc_unmount(void* mount_data) {
- // Arguments for compatibility with other FSes
- __UNUSED(mount_data);
- /* do nothing */
- return 0;
- }
- static int proc_open(struct shim_handle* hdl, struct shim_dentry* dent, int flags) {
- const char* rel_path = qstrgetstr(&dent->rel_path);
- if (flags & (O_CREAT | O_EXCL))
- return -EACCES;
- const struct proc_ent* ent;
- int ret;
- if ((ret = proc_match_name(rel_path, &ent)) < 0)
- return ret;
- if (!ent->fs_ops || !ent->fs_ops->open)
- return -EACCES;
- hdl->flags = flags;
- return ent->fs_ops->open(hdl, rel_path, flags);
- }
- static int proc_readdir(struct shim_dentry* dent, struct shim_dirent** dirent) {
- const char* rel_path = qstrgetstr(&dent->rel_path);
- const struct proc_ent* ent;
- int ret;
- if ((ret = proc_match_name(rel_path, &ent)) < 0)
- return ret;
- if (!ent->dir)
- return -ENOTDIR;
- const struct proc_dir* dir = ent->dir;
- HASHTYPE self_hash = hash_path(rel_path, dent->rel_path.len);
- HASHTYPE new_hash;
- struct shim_dirent* buf;
- struct shim_dirent* ptr;
- int buf_size = MAX_PATH;
- retry:
- buf = malloc(buf_size);
- *dirent = ptr = buf;
- struct shim_dirent** last = dirent;
- for (const struct proc_ent* tmp = dir->ent; tmp < dir->ent + dir->size; tmp++) {
- if (tmp->name) {
- int name_len = strlen(tmp->name);
- if ((void*)(ptr + 1) + name_len + 1 > (void*)buf + buf_size)
- goto enlarge;
- new_hash = rehash_name(self_hash, tmp->name, name_len);
- ptr->next = (void*)(ptr + 1) + name_len + 1;
- ptr->ino = new_hash;
- ptr->type =
- tmp->dir ? LINUX_DT_DIR
- : (tmp->fs_ops && tmp->fs_ops->follow_link ? LINUX_DT_LNK : LINUX_DT_REG);
- memcpy(ptr->name, tmp->name, name_len + 1);
- last = &ptr->next;
- ptr = *last;
- continue;
- }
- if (tmp->nm_ops && tmp->nm_ops->list_name) {
- struct shim_dirent* d = ptr;
- int ret = tmp->nm_ops->list_name(rel_path, &ptr, (void*)buf + buf_size - (void*)ptr);
- if (ret == -ENOBUFS)
- goto enlarge;
- if (ret < 0)
- ptr = d;
- else
- for (; d && d != ptr; d = d->next) {
- last = &d->next;
- }
- continue;
- }
- }
- *last = NULL;
- if (!(*dirent))
- free(buf);
- return 0;
- enlarge:
- buf_size *= 2;
- free(buf);
- goto retry;
- }
- static int proc_stat(struct shim_dentry* dent, struct stat* buf) {
- const char* rel_path = qstrgetstr(&dent->rel_path);
- const struct proc_ent* ent;
- int ret;
- if ((ret = proc_match_name(rel_path, &ent)) < 0)
- return ret;
- if (!ent->fs_ops || !ent->fs_ops->stat)
- return -EACCES;
- return ent->fs_ops->stat(rel_path, buf);
- }
- static int proc_follow_link(struct shim_dentry* dent, struct shim_qstr* link) {
- const char* rel_path = qstrgetstr(&dent->rel_path);
- const struct proc_ent* ent;
- int ret;
- if ((ret = proc_match_name(rel_path, &ent)) < 0)
- return ret;
- if (!ent->fs_ops || !ent->fs_ops->follow_link)
- return -EINVAL;
- return ent->fs_ops->follow_link(rel_path, link);
- }
- static int proc_hstat(struct shim_handle* hdl, struct stat* buf) {
- struct shim_dentry* dent = hdl->dentry;
- assert(dent);
- const char* rel_path = qstrgetstr(&dent->rel_path);
- const struct proc_ent* ent;
- int ret;
- if ((ret = proc_match_name(rel_path, &ent)) < 0)
- return ret;
- if (!ent->fs_ops || !ent->fs_ops->stat)
- return -EACCES;
- return ent->fs_ops->stat(rel_path, buf);
- }
- struct shim_fs_ops proc_fs_ops = {
- .mount = &proc_mount,
- .unmount = &proc_unmount,
- .close = &str_close,
- .read = &str_read,
- .write = &str_write,
- .seek = &str_seek,
- .flush = &str_flush,
- .hstat = &proc_hstat,
- };
- struct shim_d_ops proc_d_ops = {
- .open = &proc_open,
- .stat = &proc_stat,
- .mode = &proc_mode,
- .lookup = &proc_lookup,
- .follow_link = &proc_follow_link,
- .readdir = &proc_readdir,
- };
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