diff options
Diffstat (limited to 'fs/open.c')
| -rw-r--r-- | fs/open.c | 1076 |
1 files changed, 1076 insertions, 0 deletions
diff --git a/fs/open.c b/fs/open.c new file mode 100644 index 000000000000..963bd81a44c8 --- /dev/null +++ b/fs/open.c @@ -0,0 +1,1076 @@ +/* + * linux/fs/open.c + * + * Copyright (C) 1991, 1992 Linus Torvalds + */ + +#include <linux/string.h> +#include <linux/mm.h> +#include <linux/utime.h> +#include <linux/file.h> +#include <linux/smp_lock.h> +#include <linux/quotaops.h> +#include <linux/dnotify.h> +#include <linux/module.h> +#include <linux/slab.h> +#include <linux/tty.h> +#include <linux/namei.h> +#include <linux/backing-dev.h> +#include <linux/security.h> +#include <linux/mount.h> +#include <linux/vfs.h> +#include <asm/uaccess.h> +#include <linux/fs.h> +#include <linux/pagemap.h> +#include <linux/syscalls.h> + +#include <asm/unistd.h> + +int vfs_statfs(struct super_block *sb, struct kstatfs *buf) +{ + int retval = -ENODEV; + + if (sb) { + retval = -ENOSYS; + if (sb->s_op->statfs) { + memset(buf, 0, sizeof(*buf)); + retval = security_sb_statfs(sb); + if (retval) + return retval; + retval = sb->s_op->statfs(sb, buf); + if (retval == 0 && buf->f_frsize == 0) + buf->f_frsize = buf->f_bsize; + } + } + return retval; +} + +EXPORT_SYMBOL(vfs_statfs); + +static int vfs_statfs_native(struct super_block *sb, struct statfs *buf) +{ + struct kstatfs st; + int retval; + + retval = vfs_statfs(sb, &st); + if (retval) + return retval; + + if (sizeof(*buf) == sizeof(st)) + memcpy(buf, &st, sizeof(st)); + else { + if (sizeof buf->f_blocks == 4) { + if ((st.f_blocks | st.f_bfree | st.f_bavail) & + 0xffffffff00000000ULL) + return -EOVERFLOW; + /* + * f_files and f_ffree may be -1; it's okay to stuff + * that into 32 bits + */ + if (st.f_files != -1 && + (st.f_files & 0xffffffff00000000ULL)) + return -EOVERFLOW; + if (st.f_ffree != -1 && + (st.f_ffree & 0xffffffff00000000ULL)) + return -EOVERFLOW; + } + + buf->f_type = st.f_type; + buf->f_bsize = st.f_bsize; + buf->f_blocks = st.f_blocks; + buf->f_bfree = st.f_bfree; + buf->f_bavail = st.f_bavail; + buf->f_files = st.f_files; + buf->f_ffree = st.f_ffree; + buf->f_fsid = st.f_fsid; + buf->f_namelen = st.f_namelen; + buf->f_frsize = st.f_frsize; + memset(buf->f_spare, 0, sizeof(buf->f_spare)); + } + return 0; +} + +static int vfs_statfs64(struct super_block *sb, struct statfs64 *buf) +{ + struct kstatfs st; + int retval; + + retval = vfs_statfs(sb, &st); + if (retval) + return retval; + + if (sizeof(*buf) == sizeof(st)) + memcpy(buf, &st, sizeof(st)); + else { + buf->f_type = st.f_type; + buf->f_bsize = st.f_bsize; + buf->f_blocks = st.f_blocks; + buf->f_bfree = st.f_bfree; + buf->f_bavail = st.f_bavail; + buf->f_files = st.f_files; + buf->f_ffree = st.f_ffree; + buf->f_fsid = st.f_fsid; + buf->f_namelen = st.f_namelen; + buf->f_frsize = st.f_frsize; + memset(buf->f_spare, 0, sizeof(buf->f_spare)); + } + return 0; +} + +asmlinkage long sys_statfs(const char __user * path, struct statfs __user * buf) +{ + struct nameidata nd; + int error; + + error = user_path_walk(path, &nd); + if (!error) { + struct statfs tmp; + error = vfs_statfs_native(nd.dentry->d_inode->i_sb, &tmp); + if (!error && copy_to_user(buf, &tmp, sizeof(tmp))) + error = -EFAULT; + path_release(&nd); + } + return error; +} + + +asmlinkage long sys_statfs64(const char __user *path, size_t sz, struct statfs64 __user *buf) +{ + struct nameidata nd; + long error; + + if (sz != sizeof(*buf)) + return -EINVAL; + error = user_path_walk(path, &nd); + if (!error) { + struct statfs64 tmp; + error = vfs_statfs64(nd.dentry->d_inode->i_sb, &tmp); + if (!error && copy_to_user(buf, &tmp, sizeof(tmp))) + error = -EFAULT; + path_release(&nd); + } + return error; +} + + +asmlinkage long sys_fstatfs(unsigned int fd, struct statfs __user * buf) +{ + struct file * file; + struct statfs tmp; + int error; + + error = -EBADF; + file = fget(fd); + if (!file) + goto out; + error = vfs_statfs_native(file->f_dentry->d_inode->i_sb, &tmp); + if (!error && copy_to_user(buf, &tmp, sizeof(tmp))) + error = -EFAULT; + fput(file); +out: + return error; +} + +asmlinkage long sys_fstatfs64(unsigned int fd, size_t sz, struct statfs64 __user *buf) +{ + struct file * file; + struct statfs64 tmp; + int error; + + if (sz != sizeof(*buf)) + return -EINVAL; + + error = -EBADF; + file = fget(fd); + if (!file) + goto out; + error = vfs_statfs64(file->f_dentry->d_inode->i_sb, &tmp); + if (!error && copy_to_user(buf, &tmp, sizeof(tmp))) + error = -EFAULT; + fput(file); +out: + return error; +} + +int do_truncate(struct dentry *dentry, loff_t length) +{ + int err; + struct iattr newattrs; + + /* Not pretty: "inode->i_size" shouldn't really be signed. But it is. */ + if (length < 0) + return -EINVAL; + + newattrs.ia_size = length; + newattrs.ia_valid = ATTR_SIZE | ATTR_CTIME; + + down(&dentry->d_inode->i_sem); + err = notify_change(dentry, &newattrs); + up(&dentry->d_inode->i_sem); + return err; +} + +static inline long do_sys_truncate(const char __user * path, loff_t length) +{ + struct nameidata nd; + struct inode * inode; + int error; + + error = -EINVAL; + if (length < 0) /* sorry, but loff_t says... */ + goto out; + + error = user_path_walk(path, &nd); + if (error) + goto out; + inode = nd.dentry->d_inode; + + /* For directories it's -EISDIR, for other non-regulars - -EINVAL */ + error = -EISDIR; + if (S_ISDIR(inode->i_mode)) + goto dput_and_out; + + error = -EINVAL; + if (!S_ISREG(inode->i_mode)) + goto dput_and_out; + + error = permission(inode,MAY_WRITE,&nd); + if (error) + goto dput_and_out; + + error = -EROFS; + if (IS_RDONLY(inode)) + goto dput_and_out; + + error = -EPERM; + if (IS_IMMUTABLE(inode) || IS_APPEND(inode)) + goto dput_and_out; + + /* + * Make sure that there are no leases. + */ + error = break_lease(inode, FMODE_WRITE); + if (error) + goto dput_and_out; + + error = get_write_access(inode); + if (error) + goto dput_and_out; + + error = locks_verify_truncate(inode, NULL, length); + if (!error) { + DQUOT_INIT(inode); + error = do_truncate(nd.dentry, length); + } + put_write_access(inode); + +dput_and_out: + path_release(&nd); +out: + return error; +} + +asmlinkage long sys_truncate(const char __user * path, unsigned long length) +{ + /* on 32-bit boxen it will cut the range 2^31--2^32-1 off */ + return do_sys_truncate(path, (long)length); +} + +static inline long do_sys_ftruncate(unsigned int fd, loff_t length, int small) +{ + struct inode * inode; + struct dentry *dentry; + struct file * file; + int error; + + error = -EINVAL; + if (length < 0) + goto out; + error = -EBADF; + file = fget(fd); + if (!file) + goto out; + + /* explicitly opened as large or we are on 64-bit box */ + if (file->f_flags & O_LARGEFILE) + small = 0; + + dentry = file->f_dentry; + inode = dentry->d_inode; + error = -EINVAL; + if (!S_ISREG(inode->i_mode) || !(file->f_mode & FMODE_WRITE)) + goto out_putf; + + error = -EINVAL; + /* Cannot ftruncate over 2^31 bytes without large file support */ + if (small && length > MAX_NON_LFS) + goto out_putf; + + error = -EPERM; + if (IS_APPEND(inode)) + goto out_putf; + + error = locks_verify_truncate(inode, file, length); + if (!error) + error = do_truncate(dentry, length); +out_putf: + fput(file); +out: + return error; +} + +asmlinkage long sys_ftruncate(unsigned int fd, unsigned long length) +{ + return do_sys_ftruncate(fd, length, 1); +} + +/* LFS versions of truncate are only needed on 32 bit machines */ +#if BITS_PER_LONG == 32 +asmlinkage long sys_truncate64(const char __user * path, loff_t length) +{ + return do_sys_truncate(path, length); +} + +asmlinkage long sys_ftruncate64(unsigned int fd, loff_t length) +{ + return do_sys_ftruncate(fd, length, 0); +} +#endif + +#ifdef __ARCH_WANT_SYS_UTIME + +/* + * sys_utime() can be implemented in user-level using sys_utimes(). + * Is this for backwards compatibility? If so, why not move it + * into the appropriate arch directory (for those architectures that + * need it). + */ + +/* If times==NULL, set access and modification to current time, + * must be owner or have write permission. + * Else, update from *times, must be owner or super user. + */ +asmlinkage long sys_utime(char __user * filename, struct utimbuf __user * times) +{ + int error; + struct nameidata nd; + struct inode * inode; + struct iattr newattrs; + + error = user_path_walk(filename, &nd); + if (error) + goto out; + inode = nd.dentry->d_inode; + + error = -EROFS; + if (IS_RDONLY(inode)) + goto dput_and_out; + + /* Don't worry, the checks are done in inode_change_ok() */ + newattrs.ia_valid = ATTR_CTIME | ATTR_MTIME | ATTR_ATIME; + if (times) { + error = -EPERM; + if (IS_APPEND(inode) || IS_IMMUTABLE(inode)) + goto dput_and_out; + + error = get_user(newattrs.ia_atime.tv_sec, ×->actime); + newattrs.ia_atime.tv_nsec = 0; + if (!error) + error = get_user(newattrs.ia_mtime.tv_sec, ×->modtime); + newattrs.ia_mtime.tv_nsec = 0; + if (error) + goto dput_and_out; + + newattrs.ia_valid |= ATTR_ATIME_SET | ATTR_MTIME_SET; + } else { + error = -EACCES; + if (IS_IMMUTABLE(inode)) + goto dput_and_out; + + if (current->fsuid != inode->i_uid && + (error = permission(inode,MAY_WRITE,&nd)) != 0) + goto dput_and_out; + } + down(&inode->i_sem); + error = notify_change(nd.dentry, &newattrs); + up(&inode->i_sem); +dput_and_out: + path_release(&nd); +out: + return error; +} + +#endif + +/* If times==NULL, set access and modification to current time, + * must be owner or have write permission. + * Else, update from *times, must be owner or super user. + */ +long do_utimes(char __user * filename, struct timeval * times) +{ + int error; + struct nameidata nd; + struct inode * inode; + struct iattr newattrs; + + error = user_path_walk(filename, &nd); + + if (error) + goto out; + inode = nd.dentry->d_inode; + + error = -EROFS; + if (IS_RDONLY(inode)) + goto dput_and_out; + + /* Don't worry, the checks are done in inode_change_ok() */ + newattrs.ia_valid = ATTR_CTIME | ATTR_MTIME | ATTR_ATIME; + if (times) { + error = -EPERM; + if (IS_APPEND(inode) || IS_IMMUTABLE(inode)) + goto dput_and_out; + + newattrs.ia_atime.tv_sec = times[0].tv_sec; + newattrs.ia_atime.tv_nsec = times[0].tv_usec * 1000; + newattrs.ia_mtime.tv_sec = times[1].tv_sec; + newattrs.ia_mtime.tv_nsec = times[1].tv_usec * 1000; + newattrs.ia_valid |= ATTR_ATIME_SET | ATTR_MTIME_SET; + } else { + error = -EACCES; + if (IS_IMMUTABLE(inode)) + goto dput_and_out; + + if (current->fsuid != inode->i_uid && + (error = permission(inode,MAY_WRITE,&nd)) != 0) + goto dput_and_out; + } + down(&inode->i_sem); + error = notify_change(nd.dentry, &newattrs); + up(&inode->i_sem); +dput_and_out: + path_release(&nd); +out: + return error; +} + +asmlinkage long sys_utimes(char __user * filename, struct timeval __user * utimes) +{ + struct timeval times[2]; + + if (utimes && copy_from_user(×, utimes, sizeof(times))) + return -EFAULT; + return do_utimes(filename, utimes ? times : NULL); +} + + +/* + * access() needs to use the real uid/gid, not the effective uid/gid. + * We do this by temporarily clearing all FS-related capabilities and + * switching the fsuid/fsgid around to the real ones. + */ +asmlinkage long sys_access(const char __user * filename, int mode) +{ + struct nameidata nd; + int old_fsuid, old_fsgid; + kernel_cap_t old_cap; + int res; + + if (mode & ~S_IRWXO) /* where's F_OK, X_OK, W_OK, R_OK? */ + return -EINVAL; + + old_fsuid = current->fsuid; + old_fsgid = current->fsgid; + old_cap = current->cap_effective; + + current->fsuid = current->uid; + current->fsgid = current->gid; + + /* + * Clear the capabilities if we switch to a non-root user + * + * FIXME: There is a race here against sys_capset. The + * capabilities can change yet we will restore the old + * value below. We should hold task_capabilities_lock, + * but we cannot because user_path_walk can sleep. + */ + if (current->uid) + cap_clear(current->cap_effective); + else + current->cap_effective = current->cap_permitted; + + res = __user_walk(filename, LOOKUP_FOLLOW|LOOKUP_ACCESS, &nd); + if (!res) { + res = permission(nd.dentry->d_inode, mode, &nd); + /* SuS v2 requires we report a read only fs too */ + if(!res && (mode & S_IWOTH) && IS_RDONLY(nd.dentry->d_inode) + && !special_file(nd.dentry->d_inode->i_mode)) + res = -EROFS; + path_release(&nd); + } + + current->fsuid = old_fsuid; + current->fsgid = old_fsgid; + current->cap_effective = old_cap; + + return res; +} + +asmlinkage long sys_chdir(const char __user * filename) +{ + struct nameidata nd; + int error; + + error = __user_walk(filename, LOOKUP_FOLLOW|LOOKUP_DIRECTORY, &nd); + if (error) + goto out; + + error = permission(nd.dentry->d_inode,MAY_EXEC,&nd); + if (error) + goto dput_and_out; + + set_fs_pwd(current->fs, nd.mnt, nd.dentry); + +dput_and_out: + path_release(&nd); +out: + return error; +} + +asmlinkage long sys_fchdir(unsigned int fd) +{ + struct file *file; + struct dentry *dentry; + struct inode *inode; + struct vfsmount *mnt; + int error; + + error = -EBADF; + file = fget(fd); + if (!file) + goto out; + + dentry = file->f_dentry; + mnt = file->f_vfsmnt; + inode = dentry->d_inode; + + error = -ENOTDIR; + if (!S_ISDIR(inode->i_mode)) + goto out_putf; + + error = permission(inode, MAY_EXEC, NULL); + if (!error) + set_fs_pwd(current->fs, mnt, dentry); +out_putf: + fput(file); +out: + return error; +} + +asmlinkage long sys_chroot(const char __user * filename) +{ + struct nameidata nd; + int error; + + error = __user_walk(filename, LOOKUP_FOLLOW | LOOKUP_DIRECTORY | LOOKUP_NOALT, &nd); + if (error) + goto out; + + error = permission(nd.dentry->d_inode,MAY_EXEC,&nd); + if (error) + goto dput_and_out; + + error = -EPERM; + if (!capable(CAP_SYS_CHROOT)) + goto dput_and_out; + + set_fs_root(current->fs, nd.mnt, nd.dentry); + set_fs_altroot(); + error = 0; +dput_and_out: + path_release(&nd); +out: + return error; +} + +asmlinkage long sys_fchmod(unsigned int fd, mode_t mode) +{ + struct inode * inode; + struct dentry * dentry; + struct file * file; + int err = -EBADF; + struct iattr newattrs; + + file = fget(fd); + if (!file) + goto out; + + dentry = file->f_dentry; + inode = dentry->d_inode; + + err = -EROFS; + if (IS_RDONLY(inode)) + goto out_putf; + err = -EPERM; + if (IS_IMMUTABLE(inode) || IS_APPEND(inode)) + goto out_putf; + down(&inode->i_sem); + if (mode == (mode_t) -1) + mode = inode->i_mode; + newattrs.ia_mode = (mode & S_IALLUGO) | (inode->i_mode & ~S_IALLUGO); + newattrs.ia_valid = ATTR_MODE | ATTR_CTIME; + err = notify_change(dentry, &newattrs); + up(&inode->i_sem); + +out_putf: + fput(file); +out: + return err; +} + +asmlinkage long sys_chmod(const char __user * filename, mode_t mode) +{ + struct nameidata nd; + struct inode * inode; + int error; + struct iattr newattrs; + + error = user_path_walk(filename, &nd); + if (error) + goto out; + inode = nd.dentry->d_inode; + + error = -EROFS; + if (IS_RDONLY(inode)) + goto dput_and_out; + + error = -EPERM; + if (IS_IMMUTABLE(inode) || IS_APPEND(inode)) + goto dput_and_out; + + down(&inode->i_sem); + if (mode == (mode_t) -1) + mode = inode->i_mode; + newattrs.ia_mode = (mode & S_IALLUGO) | (inode->i_mode & ~S_IALLUGO); + newattrs.ia_valid = ATTR_MODE | ATTR_CTIME; + error = notify_change(nd.dentry, &newattrs); + up(&inode->i_sem); + +dput_and_out: + path_release(&nd); +out: + return error; +} + +static int chown_common(struct dentry * dentry, uid_t user, gid_t group) +{ + struct inode * inode; + int error; + struct iattr newattrs; + + error = -ENOENT; + if (!(inode = dentry->d_inode)) { + printk(KERN_ERR "chown_common: NULL inode\n"); + goto out; + } + error = -EROFS; + if (IS_RDONLY(inode)) + goto out; + error = -EPERM; + if (IS_IMMUTABLE(inode) || IS_APPEND(inode)) + goto out; + newattrs.ia_valid = ATTR_CTIME; + if (user != (uid_t) -1) { + newattrs.ia_valid |= ATTR_UID; + newattrs.ia_uid = user; + } + if (group != (gid_t) -1) { + newattrs.ia_valid |= ATTR_GID; + newattrs.ia_gid = group; + } + if (!S_ISDIR(inode->i_mode)) + newattrs.ia_valid |= ATTR_KILL_SUID|ATTR_KILL_SGID; + down(&inode->i_sem); + error = notify_change(dentry, &newattrs); + up(&inode->i_sem); +out: + return error; +} + +asmlinkage long sys_chown(const char __user * filename, uid_t user, gid_t group) +{ + struct nameidata nd; + int error; + + error = user_path_walk(filename, &nd); + if (!error) { + error = chown_common(nd.dentry, user, group); + path_release(&nd); + } + return error; +} + +asmlinkage long sys_lchown(const char __user * filename, uid_t user, gid_t group) +{ + struct nameidata nd; + int error; + + error = user_path_walk_link(filename, &nd); + if (!error) { + error = chown_common(nd.dentry, user, group); + path_release(&nd); + } + return error; +} + + +asmlinkage long sys_fchown(unsigned int fd, uid_t user, gid_t group) +{ + struct file * file; + int error = -EBADF; + + file = fget(fd); + if (file) { + error = chown_common(file->f_dentry, user, group); + fput(file); + } + return error; +} + +/* + * Note that while the flag value (low two bits) for sys_open means: + * 00 - read-only + * 01 - write-only + * 10 - read-write + * 11 - special + * it is changed into + * 00 - no permissions needed + * 01 - read-permission + * 10 - write-permission + * 11 - read-write + * for the internal routines (ie open_namei()/follow_link() etc). 00 is + * used by symlinks. + */ +struct file *filp_open(const char * filename, int flags, int mode) +{ + int namei_flags, error; + struct nameidata nd; + + namei_flags = flags; + if ((namei_flags+1) & O_ACCMODE) + namei_flags++; + if (namei_flags & O_TRUNC) + namei_flags |= 2; + + error = open_namei(filename, namei_flags, mode, &nd); + if (!error) + return dentry_open(nd.dentry, nd.mnt, flags); + + return ERR_PTR(error); +} + +EXPORT_SYMBOL(filp_open); + +struct file *dentry_open(struct dentry *dentry, struct vfsmount *mnt, int flags) +{ + struct file * f; + struct inode *inode; + int error; + + error = -ENFILE; + f = get_empty_filp(); + if (!f) + goto cleanup_dentry; + f->f_flags = flags; + f->f_mode = ((flags+1) & O_ACCMODE) | FMODE_LSEEK | FMODE_PREAD | FMODE_PWRITE; + inode = dentry->d_inode; + if (f->f_mode & FMODE_WRITE) { + error = get_write_access(inode); + if (error) + goto cleanup_file; + } + + f->f_mapping = inode->i_mapping; + f->f_dentry = dentry; + f->f_vfsmnt = mnt; + f->f_pos = 0; + f->f_op = fops_get(inode->i_fop); + file_move(f, &inode->i_sb->s_files); + + if (f->f_op && f->f_op->open) { + error = f->f_op->open(inode,f); + if (error) + goto cleanup_all; + } + f->f_flags &= ~(O_CREAT | O_EXCL | O_NOCTTY | O_TRUNC); + + file_ra_state_init(&f->f_ra, f->f_mapping->host->i_mapping); + + /* NB: we're sure to have correct a_ops only after f_op->open */ + if (f->f_flags & O_DIRECT) { + if (!f->f_mapping->a_ops || !f->f_mapping->a_ops->direct_IO) { + fput(f); + f = ERR_PTR(-EINVAL); + } + } + + return f; + +cleanup_all: + fops_put(f->f_op); + if (f->f_mode & FMODE_WRITE) + put_write_access(inode); + file_kill(f); + f->f_dentry = NULL; + f->f_vfsmnt = NULL; +cleanup_file: + put_filp(f); +cleanup_dentry: + dput(dentry); + mntput(mnt); + return ERR_PTR(error); +} + +EXPORT_SYMBOL(dentry_open); + +/* + * Find an empty file descriptor entry, and mark it busy. + */ +int get_unused_fd(void) +{ + struct files_struct * files = current->files; + int fd, error; + + error = -EMFILE; + spin_lock(&files->file_lock); + +repeat: + fd = find_next_zero_bit(files->open_fds->fds_bits, + files->max_fdset, + files->next_fd); + + /* + * N.B. For clone tasks sharing a files structure, this test + * will limit the total number of files that can be opened. + */ + if (fd >= current->signal->rlim[RLIMIT_NOFILE].rlim_cur) + goto out; + + /* Do we need to expand the fd array or fd set? */ + error = expand_files(files, fd); + if (error < 0) + goto out; + + if (error) { + /* + * If we needed to expand the fs array we + * might have blocked - try again. + */ + error = -EMFILE; + goto repeat; + } + + FD_SET(fd, files->open_fds); + FD_CLR(fd, files->close_on_exec); + files->next_fd = fd + 1; +#if 1 + /* Sanity check */ + if (files->fd[fd] != NULL) { + printk(KERN_WARNING "get_unused_fd: slot %d not NULL!\n", fd); + files->fd[fd] = NULL; + } +#endif + error = fd; + +out: + spin_unlock(&files->file_lock); + return error; +} + +EXPORT_SYMBOL(get_unused_fd); + +static inline void __put_unused_fd(struct files_struct *files, unsigned int fd) +{ + __FD_CLR(fd, files->open_fds); + if (fd < files->next_fd) + files->next_fd = fd; +} + +void fastcall put_unused_fd(unsigned int fd) +{ + struct files_struct *files = current->files; + spin_lock(&files->file_lock); + __put_unused_fd(files, fd); + spin_unlock(&files->file_lock); +} + +EXPORT_SYMBOL(put_unused_fd); + +/* + * Install a file pointer in the fd array. + * + * The VFS is full of places where we drop the files lock between + * setting the open_fds bitmap and installing the file in the file + * array. At any such point, we are vulnerable to a dup2() race + * installing a file in the array before us. We need to detect this and + * fput() the struct file we are about to overwrite in this case. + * + * It should never happen - if we allow dup2() do it, _really_ bad things + * will follow. + */ + +void fastcall fd_install(unsigned int fd, struct file * file) +{ + struct files_struct *files = current->files; + spin_lock(&files->file_lock); + if (unlikely(files->fd[fd] != NULL)) + BUG(); + files->fd[fd] = file; + spin_unlock(&files->file_lock); +} + +EXPORT_SYMBOL(fd_install); + +asmlinkage long sys_open(const char __user * filename, int flags, int mode) +{ + char * tmp; + int fd, error; + +#if BITS_PER_LONG != 32 + flags |= O_LARGEFILE; +#endif + tmp = getname(filename); + fd = PTR_ERR(tmp); + if (!IS_ERR(tmp)) { + fd = get_unused_fd(); + if (fd >= 0) { + struct file *f = filp_open(tmp, flags, mode); + error = PTR_ERR(f); + if (IS_ERR(f)) + goto out_error; + fd_install(fd, f); + } +out: + putname(tmp); + } + return fd; + +out_error: + put_unused_fd(fd); + fd = error; + goto out; +} +EXPORT_SYMBOL_GPL(sys_open); + +#ifndef __alpha__ + +/* + * For backward compatibility? Maybe this should be moved + * into arch/i386 instead? + */ +asmlinkage long sys_creat(const char __user * pathname, int mode) +{ + return sys_open(pathname, O_CREAT | O_WRONLY | O_TRUNC, mode); +} + +#endif + +/* + * "id" is the POSIX thread ID. We use the + * files pointer for this.. + */ +int filp_close(struct file *filp, fl_owner_t id) +{ + int retval; + + /* Report and clear outstanding errors */ + retval = filp->f_error; + if (retval) + filp->f_error = 0; + + if (!file_count(filp)) { + printk(KERN_ERR "VFS: Close: file count is 0\n"); + return retval; + } + + if (filp->f_op && filp->f_op->flush) { + int err = filp->f_op->flush(filp); + if (!retval) + retval = err; + } + + dnotify_flush(filp, id); + locks_remove_posix(filp, id); + fput(filp); + return retval; +} + +EXPORT_SYMBOL(filp_close); + +/* + * Careful here! We test whether the file pointer is NULL before + * releasing the fd. This ensures that one clone task can't release + * an fd while another clone is opening it. + */ +asmlinkage long sys_close(unsigned int fd) +{ + struct file * filp; + struct files_struct *files = current->files; + + spin_lock(&files->file_lock); + if (fd >= files->max_fds) + goto out_unlock; + filp = files->fd[fd]; + if (!filp) + goto out_unlock; + files->fd[fd] = NULL; + FD_CLR(fd, files->close_on_exec); + __put_unused_fd(files, fd); + spin_unlock(&files->file_lock); + return filp_close(filp, files); + +out_unlock: + spin_unlock(&files->file_lock); + return -EBADF; +} + +EXPORT_SYMBOL(sys_close); + +/* + * This routine simulates a hangup on the tty, to arrange that users + * are given clean terminals at login time. + */ +asmlinkage long sys_vhangup(void) +{ + if (capable(CAP_SYS_TTY_CONFIG)) { + tty_vhangup(current->signal->tty); + return 0; + } + return -EPERM; +} + +/* + * Called when an inode is about to be open. + * We use this to disallow opening large files on 32bit systems if + * the caller didn't specify O_LARGEFILE. On 64bit systems we force + * on this flag in sys_open. + */ +int generic_file_open(struct inode * inode, struct file * filp) +{ + if (!(filp->f_flags & O_LARGEFILE) && i_size_read(inode) > MAX_NON_LFS) + return -EFBIG; + return 0; +} + +EXPORT_SYMBOL(generic_file_open); + +/* + * This is used by subsystems that don't want seekable + * file descriptors + */ +int nonseekable_open(struct inode *inode, struct file *filp) +{ + filp->f_mode &= ~(FMODE_LSEEK | FMODE_PREAD | FMODE_PWRITE); + return 0; +} + +EXPORT_SYMBOL(nonseekable_open); |