/* 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 . */
/*
* shim_stat.c
*
* Implementation of system call "stat", "lstat", "fstat" and "readlink".
*/
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
int shim_do_stat(const char* file, struct stat* stat) {
if (!file || test_user_string(file))
return -EFAULT;
if (!stat || test_user_memory(stat, sizeof(*stat), true))
return -EFAULT;
int ret;
struct shim_dentry* dent = NULL;
if ((ret = path_lookupat(NULL, file, LOOKUP_ACCESS | LOOKUP_FOLLOW, &dent, NULL)) < 0)
goto out;
struct shim_mount* fs = dent->fs;
if (!fs->d_ops || !fs->d_ops->stat) {
ret = -EACCES;
goto out_dentry;
}
ret = fs->d_ops->stat(dent, stat);
out_dentry:
put_dentry(dent);
out:
return ret;
}
int shim_do_lstat(const char* file, struct stat* stat) {
if (!file || test_user_string(file))
return -EFAULT;
if (!stat || test_user_memory(stat, sizeof(*stat), true))
return -EFAULT;
int ret;
struct shim_dentry* dent = NULL;
if ((ret = path_lookupat(NULL, file, LOOKUP_ACCESS, &dent, NULL)) < 0)
goto out;
struct shim_mount* fs = dent->fs;
if (!fs->d_ops || !fs->d_ops->stat) {
ret = -EACCES;
goto out_dentry;
}
ret = fs->d_ops->stat(dent, stat);
out_dentry:
put_dentry(dent);
out:
return ret;
}
int shim_do_fstat(int fd, struct stat* stat) {
struct shim_handle* hdl = get_fd_handle(fd, NULL, NULL);
if (!hdl)
return -EBADF;
int ret = -EACCES;
struct shim_mount* fs = hdl->fs;
if (!fs || !fs->fs_ops)
goto out;
if (!fs->fs_ops->hstat)
goto out;
ret = fs->fs_ops->hstat(hdl, stat);
out:
put_handle(hdl);
return ret;
}
int shim_do_readlink(const char* file, char* buf, size_t bufsize) {
if (!file || test_user_string(file))
return -EFAULT;
if (!buf || !bufsize || test_user_memory(buf, bufsize, true))
return -EFAULT;
if (bufsize <= 0)
return -EINVAL;
int ret;
struct shim_dentry* dent = NULL;
struct shim_qstr qstr = QSTR_INIT;
if ((ret = path_lookupat(NULL, file, LOOKUP_ACCESS, &dent, NULL)) < 0)
return ret;
ret = -EINVAL;
/* The correct behavior is to return -EINVAL if file is not a
symbolic link */
if (!(dent->state & DENTRY_ISLINK))
goto out;
if (!dent->fs || !dent->fs->d_ops || !dent->fs->d_ops->follow_link)
goto out;
ret = dent->fs->d_ops->follow_link(dent, &qstr);
if (ret < 0)
goto out;
ret = -ENAMETOOLONG;
if (qstr.len >= bufsize)
goto out;
memcpy(buf, qstrgetstr(&qstr), qstr.len);
ret = qstr.len;
out:
put_dentry(dent);
return ret;
}
static int __do_statfs(struct shim_mount* fs, struct statfs* buf) {
__UNUSED(fs);
if (!buf || test_user_memory(buf, sizeof(*buf), true))
return -EFAULT;
memset(buf, 0, sizeof(*buf));
buf->f_bsize = 4096;
buf->f_blocks = 20000000;
buf->f_bfree = 10000000;
buf->f_bavail = 10000000;
debug("statfs: %ld %ld %ld\n", buf->f_blocks, buf->f_bfree, buf->f_bavail);
return 0;
}
int shim_do_statfs(const char* path, struct statfs* buf) {
if (!path || test_user_string(path))
return -EFAULT;
int ret;
struct shim_dentry* dent = NULL;
if ((ret = path_lookupat(NULL, path, LOOKUP_ACCESS | LOOKUP_FOLLOW, &dent, NULL)) < 0)
return ret;
struct shim_mount* fs = dent->fs;
put_dentry(dent);
return __do_statfs(fs, buf);
}
int shim_do_fstatfs(int fd, struct statfs* buf) {
struct shim_handle* hdl = get_fd_handle(fd, NULL, NULL);
if (!hdl)
return -EBADF;
struct shim_mount* fs = hdl->fs;
put_handle(hdl);
return __do_statfs(fs, buf);
}
int shim_do_newfstatat(int dirfd, const char* pathname, struct stat* statbuf, int flags) {
if (flags & ~(AT_EMPTY_PATH | AT_NO_AUTOMOUNT | AT_SYMLINK_NOFOLLOW))
return -EINVAL;
if (test_user_string(pathname))
return -EFAULT;
if (test_user_memory(statbuf, sizeof(*statbuf), true))
return -EFAULT;
int lookup_flags = LOOKUP_ACCESS | LOOKUP_FOLLOW;
if (flags & AT_SYMLINK_NOFOLLOW)
lookup_flags &= ~LOOKUP_FOLLOW;
if (flags & AT_NO_AUTOMOUNT) {
/* Do nothing as automount isn't supported */
debug("ignoring AT_NO_AUTOMOUNT.");
}
if (!*pathname) {
if (!(flags & AT_EMPTY_PATH))
return -ENOENT;
if (dirfd == AT_FDCWD) {
struct shim_dentry* cwd = get_cur_thread()->cwd;
struct shim_d_ops* d_ops = cwd->fs->d_ops;
if (d_ops && d_ops->stat)
return d_ops->stat(cwd, statbuf);
return -EACCES;
}
return shim_do_fstat(dirfd, statbuf);
}
struct shim_dentry* dir = NULL;
if (*pathname != '/') {
int ret = get_dirfd_dentry(dirfd, &dir);
if (ret < 0)
return ret;
}
struct shim_dentry* dent;
int ret = path_lookupat(dir, pathname, lookup_flags, &dent, NULL);
if (ret >= 0) {
struct shim_d_ops* d_ops = dent->fs->d_ops;
if (d_ops && d_ops->stat)
ret = d_ops->stat(dent, statbuf);
else
ret = -EACCES;
put_dentry(dent);
}
if (dir)
put_dentry(dir);
return ret;
}