/* * linux/fs/read_write.c * * Copyright (C) 1991, 1992 Linus Torvalds */ #include #include #include #include #include #include #include #include #include #include #include #include #include "internal.h" #include #include typedef ssize_t (*io_fn_t)(struct file *, char __user *, size_t, loff_t *); typedef ssize_t (*iov_fn_t)(struct kiocb *, const struct iovec *, unsigned long, loff_t); typedef ssize_t (*iter_fn_t)(struct kiocb *, struct iov_iter *); const struct file_operations generic_ro_fops = { .llseek = generic_file_llseek, .read = new_sync_read, .read_iter = generic_file_read_iter, .mmap = generic_file_readonly_mmap, .splice_read = generic_file_splice_read, }; EXPORT_SYMBOL(generic_ro_fops); static inline int unsigned_offsets(struct file *file) { return file->f_mode & FMODE_UNSIGNED_OFFSET; } /** * vfs_setpos - update the file offset for lseek * @file: file structure in question * @offset: file offset to seek to * @maxsize: maximum file size * * This is a low-level filesystem helper for updating the file offset to * the value specified by @offset if the given offset is valid and it is * not equal to the current file offset. * * Return the specified offset on success and -EINVAL on invalid offset. */ loff_t vfs_setpos(struct file *file, loff_t offset, loff_t maxsize) { if (offset < 0 && !unsigned_offsets(file)) return -EINVAL; if (offset > maxsize) return -EINVAL; if (offset != file->f_pos) { file->f_pos = offset; file->f_version = 0; } return offset; } EXPORT_SYMBOL(vfs_setpos); /** * generic_file_llseek_size - generic llseek implementation for regular files * @file: file structure to seek on * @offset: file offset to seek to * @whence: type of seek * @size: max size of this file in file system * @eof: offset used for SEEK_END position * * This is a variant of generic_file_llseek that allows passing in a custom * maximum file size and a custom EOF position, for e.g. hashed directories * * Synchronization: * SEEK_SET and SEEK_END are unsynchronized (but atomic on 64bit platforms) * SEEK_CUR is synchronized against other SEEK_CURs, but not read/writes. * read/writes behave like SEEK_SET against seeks. */ loff_t generic_file_llseek_size(struct file *file, loff_t offset, int whence, loff_t maxsize, loff_t eof) { switch (whence) { case SEEK_END: offset += eof; break; case SEEK_CUR: /* * Here we special-case the lseek(fd, 0, SEEK_CUR) * position-querying operation. Avoid rewriting the "same" * f_pos value back to the file because a concurrent read(), * write() or lseek() might have altered it */ if (offset == 0) return file->f_pos; /* * f_lock protects against read/modify/write race with other * SEEK_CURs. Note that parallel writes and reads behave * like SEEK_SET. */ spin_lock(&file->f_lock); offset = vfs_setpos(file, file->f_pos + offset, maxsize); spin_unlock(&file->f_lock); return offset; case SEEK_DATA: /* * In the generic case the entire file is data, so as long as * offset isn't at the end of the file then the offset is data. */ if (offset >= eof) return -ENXIO; break; case SEEK_HOLE: /* * There is a virtual hole at the end of the file, so as long as * offset isn't i_size or larger, return i_size. */ if (offset >= eof) return -ENXIO; offset = eof; break; } return vfs_setpos(file, offset, maxsize); } EXPORT_SYMBOL(generic_file_llseek_size); /** * generic_file_llseek - generic llseek implementation for regular files * @file: file structure to seek on * @offset: file offset to seek to * @whence: type of seek * * This is a generic implemenation of ->llseek useable for all normal local * filesystems. It just updates the file offset to the value specified by * @offset and @whence. */ loff_t generic_file_llseek(struct file *file, loff_t offset, int whence) { struct inode *inode = file->f_mapping->host; return generic_file_llseek_size(file, offset, whence, inode->i_sb->s_maxbytes, i_size_read(inode)); } EXPORT_SYMBOL(generic_file_llseek); /** * fixed_size_llseek - llseek implementation for fixed-sized devices * @file: file structure to seek on * @offset: file offset to seek to * @whence: type of seek * @size: size of the file * */ loff_t fixed_size_llseek(struct file *file, loff_t offset, int whence, loff_t size) { switch (whence) { case SEEK_SET: case SEEK_CUR: case SEEK_END: return generic_file_llseek_size(file, offset, whence, size, size); default: return -EINVAL; } } EXPORT_SYMBOL(fixed_size_llseek); /** * noop_llseek - No Operation Performed llseek implementation * @file: file structure to seek on * @offset: file offset to seek to * @whence: type of seek * * This is an implementation of ->llseek useable for the rare special case when * userspace expects the seek to succeed but the (device) file is actually not * able to perform the seek. In this case you use noop_llseek() instead of * falling back to the default implementation of ->llseek. */ loff_t noop_llseek(struct file *file, loff_t offset, int whence) { return file->f_pos; } EXPORT_SYMBOL(noop_llseek); loff_t no_llseek(struct file *file, loff_t offset, int whence) { return -ESPIPE; } EXPORT_SYMBOL(no_llseek); loff_t default_llseek(struct file *file, loff_t offset, int whence) { struct inode *inode = file_inode(file); loff_t retval; mutex_lock(&inode->i_mutex); switch (whence) { case SEEK_END: offset += i_size_read(inode); break; case SEEK_CUR: if (offset == 0) { retval = file->f_pos; goto out; } offset += file->f_pos; break; case SEEK_DATA: /* * In the generic case the entire file is data, so as * long as offset isn't at the end of the file then the * offset is data. */ if (offset >= inode->i_size) { retval = -ENXIO; goto out; } break; case SEEK_HOLE: /* * There is a virtual hole at the end of the file, so * as long as offset isn't i_size or larger, return * i_size. */ if (offset >= inode->i_size) { retval = -ENXIO; goto out; } offset = inode->i_size; break; } retval = -EINVAL; if (offset >= 0 || unsigned_offsets(file)) { if (offset != file->f_pos) { file->f_pos = offset; file->f_version = 0; } retval = offset; } out: mutex_unlock(&inode->i_mutex); return retval; } EXPORT_SYMBOL(default_llseek); loff_t vfs_llseek(struct file *file, loff_t offset, int whence) { loff_t (*fn)(struct file *, loff_t, int); fn = no_llseek; if (file->f_mode & FMODE_LSEEK) { if (file->f_op->llseek) fn = file->f_op->llseek; } return fn(file, offset, whence); } EXPORT_SYMBOL(vfs_llseek); static inline struct fd fdget_pos(int fd) { return __to_fd(__fdget_pos(fd)); } static inline void fdput_pos(struct fd f) { if (f.flags & FDPUT_POS_UNLOCK) mutex_unlock(&f.file->f_pos_lock); fdput(f); } SYSCALL_DEFINE3(lseek, unsigned int, fd, off_t, offset, unsigned int, whence) { off_t retval; struct fd f = fdget_pos(fd); if (!f.file) return -EBADF; retval = -EINVAL; if (whence <= SEEK_MAX) { loff_t res = vfs_llseek(f.file, offset, whence); retval = res; if (res != (loff_t)retval) retval = -EOVERFLOW; /* LFS: should only happen on 32 bit platforms */ } fdput_pos(f); return retval; } #ifdef CONFIG_COMPAT COMPAT_SYSCALL_DEFINE3(lseek, unsigned int, fd, compat_off_t, offset, unsigned int, whence) { return sys_lseek(fd, offset, whence); } #endif #ifdef __ARCH_WANT_SYS_LLSEEK SYSCALL_DEFINE5(llseek, unsigned int, fd, unsigned long, offset_high, unsigned long, offset_low, loff_t __user *, result, unsigned int, whence) { int retval; struct fd f = fdget_pos(fd); loff_t offset; if (!f.file) return -EBADF; retval = -EINVAL; if (whence > SEEK_MAX) goto out_putf; offset = vfs_llseek(f.file, ((loff_t) offset_high << 32) | offset_low, whence); retval = (int)offset; if (offset >= 0) { retval = -EFAULT; if (!copy_to_user(result, &offset, sizeof(offset))) retval = 0; } out_putf: fdput_pos(f); return retval; } #endif ssize_t vfs_iter_read(struct file *file, struct iov_iter *iter, loff_t *ppos) { struct kiocb kiocb; ssize_t ret; if (!file->f_op->read_iter) return -EINVAL; init_sync_kiocb(&kiocb, file); kiocb.ki_pos = *ppos; iter->type |= READ; ret = file->f_op->read_iter(&kiocb, iter); BUG_ON(ret == -EIOCBQUEUED); if (ret > 0) *ppos = kiocb.ki_pos; return ret; } EXPORT_SYMBOL(vfs_iter_read); ssize_t vfs_iter_write(struct file *file, struct iov_iter *iter, loff_t *ppos) { struct kiocb kiocb; ssize_t ret; if (!file->f_op->write_iter) return -EINVAL; init_sync_kiocb(&kiocb, file); kiocb.ki_pos = *ppos; iter->type |= WRITE; ret = file->f_op->write_iter(&kiocb, iter); BUG_ON(ret == -EIOCBQUEUED); if (ret > 0) *ppos = kiocb.ki_pos; return ret; } EXPORT_SYMBOL(vfs_iter_write); /* * rw_verify_area doesn't like huge counts. We limit * them to something that fits in "int" so that others * won't have to do range checks all the time. */ int rw_verify_area(int read_write, struct file *file, const loff_t *ppos, size_t count) { struct inode *inode; loff_t pos; int retval = -EINVAL; inode = file_inode(file); if (unlikely((ssize_t) count < 0)) return retval; pos = *ppos; if (unlikely(pos < 0)) { if (!unsigned_offsets(file)) return retval; if (count >= -pos) /* both values are in 0..LLONG_MAX */ return -EOVERFLOW; } else if (unlikely((loff_t) (pos + count) < 0)) { if (!unsigned_offsets(file)) return retval; } if (unlikely(inode->i_flctx && mandatory_lock(inode))) { retval = locks_mandatory_area( read_write == READ ? FLOCK_VERIFY_READ : FLOCK_VERIFY_WRITE, inode, file, pos, count); if (retval < 0) return retval; } retval = security_file_permission(file, read_write == READ ? MAY_READ : MAY_WRITE); if (retval) return retval; return count > MAX_RW_COUNT ? MAX_RW_COUNT : count; } ssize_t do_sync_read(struct file *filp, char __user *buf, size_t len, loff_t *ppos) { struct iovec iov = { .iov_base = buf, .iov_len = len }; struct kiocb kiocb; ssize_t ret; init_sync_kiocb(&kiocb, filp); kiocb.ki_pos = *ppos; ret = filp->f_op->aio_read(&kiocb, &iov, 1, kiocb.ki_pos); BUG_ON(ret == -EIOCBQUEUED); *ppos = kiocb.ki_pos; return ret; } EXPORT_SYMBOL(do_sync_read); ssize_t new_sync_read(struct file *filp, char __user *buf, size_t len, loff_t *ppos) { struct iovec iov = { .iov_base = buf, .iov_len = len }; struct kiocb kiocb; struct iov_iter iter; ssize_t ret; init_sync_kiocb(&kiocb, filp); kiocb.ki_pos = *ppos; iov_iter_init(&iter, READ, &iov, 1, len); ret = filp->f_op->read_iter(&kiocb, &iter); BUG_ON(ret == -EIOCBQUEUED); *ppos = kiocb.ki_pos; return ret; } EXPORT_SYMBOL(new_sync_read); ssize_t __vfs_read(struct file *file, char __user *buf, size_t count, loff_t *pos) { ssize_t ret; if (file->f_op->read) ret = file->f_op->read(file, buf, count, pos); else if (file->f_op->aio_read) ret = do_sync_read(file, buf, count, pos); else if (file->f_op->read_iter) ret = new_sync_read(file, buf, count, pos); else ret = -EINVAL; return ret; } ssize_t vfs_read(struct file *file, char __user *buf, size_t count, loff_t *pos) { ssize_t ret; if (!(file->f_mode & FMODE_READ)) return -EBADF; if (!(file->f_mode & FMODE_CAN_READ)) return -EINVAL; if (unlikely(!access_ok(VERIFY_WRITE, buf, count))) return -EFAULT; ret = rw_verify_area(READ, file, pos, count); if (ret >= 0) { count = ret; ret = __vfs_read(file, buf, count, pos); if (ret > 0) { fsnotify_access(file); add_rchar(current, ret); } inc_syscr(current); } return ret; } EXPORT_SYMBOL(vfs_read); ssize_t do_sync_write(struct file *filp, const char __user *buf, size_t len, loff_t *ppos) { struct iovec iov = { .iov_base = (void __user *)buf, .iov_len = len }; struct kiocb kiocb; ssize_t ret; init_sync_kiocb(&kiocb, filp); kiocb.ki_pos = *ppos; ret = filp->f_op->aio_write(&kiocb, &iov, 1, kiocb.ki_pos); BUG_ON(ret == -EIOCBQUEUED); *ppos = kiocb.ki_pos; return ret; } EXPORT_SYMBOL(do_sync_write); ssize_t new_sync_write(struct file *filp, const char __user *buf, size_t len, loff_t *ppos) { struct iovec iov = { .iov_base = (void __user *)buf, .iov_len = len }; struct kiocb kiocb; struct iov_iter iter; ssize_t ret; init_sync_kiocb(&kiocb, filp); kiocb.ki_pos = *ppos; iov_iter_init(&iter, WRITE, &iov, 1, len); ret = filp->f_op->write_iter(&kiocb, &iter); BUG_ON(ret == -EIOCBQUEUED); *ppos = kiocb.ki_pos; return ret; } EXPORT_SYMBOL(new_sync_write); ssize_t __vfs_write(struct file *file, const char __user *p, size_t count, loff_t *pos) { if (file->f_op->write) return file->f_op->write(file, p, count, pos); else if (file->f_op->aio_write) return do_sync_write(file, p, count, pos); else if (file->f_op->write_iter) return new_sync_write(file, p, count, pos); else return -EINVAL; } EXPORT_SYMBOL(__vfs_write); ssize_t __kernel_write(struct file *file, const char *buf, size_t count, loff_t *pos) { mm_segment_t old_fs; const char __user *p; ssize_t ret; if (!(file->f_mode & FMODE_CAN_WRITE)) return -EINVAL; old_fs = get_fs(); set_fs(get_ds()); p = (__force const char __user *)buf; if (count > MAX_RW_COUNT) count = MAX_RW_COUNT; ret = __vfs_write(file, p, count, pos); set_fs(old_fs); if (ret > 0) { fsnotify_modify(file); add_wchar(current, ret); } inc_syscw(current); return ret; } EXPORT_SYMBOL(__kernel_write); ssize_t vfs_write(struct file *file, const char __user *buf, size_t count, loff_t *pos) { ssize_t ret; if (!(file->f_mode & FMODE_WRITE)) return -EBADF; if (!(file->f_mode & FMODE_CAN_WRITE)) return -EINVAL; if (unlikely(!access_ok(VERIFY_READ, buf, count))) return -EFAULT; ret = rw_verify_area(WRITE, file, pos, count); if (ret >= 0) { count = ret; file_start_write(file); ret = __vfs_write(file, buf, count, pos); if (ret > 0) { fsnotify_modify(file); add_wchar(current, ret); } inc_syscw(current); file_end_write(file); } return ret; } EXPORT_SYMBOL(vfs_write); static inline loff_t file_pos_read(struct file *file) { return file->f_pos; } static inline void file_pos_write(struct file *file, loff_t pos) { file->f_pos = pos; } SYSCALL_DEFINE3(read, unsigned int, fd, char __user *, buf, size_t, count) { struct fd f = fdget_pos(fd); ssize_t ret = -EBADF; if (f.file) { loff_t pos = file_pos_read(f.file); ret = vfs_read(f.file, buf, count, &pos); if (ret >= 0) file_pos_write(f.file, pos); fdput_pos(f); } return ret; } SYSCALL_DEFINE3(write, unsigned int, fd, const char __user *, buf, size_t, count) { struct fd f = fdget_pos(fd); ssize_t ret = -EBADF; if (f.file) { loff_t pos = file_pos_read(f.file); ret = vfs_write(f.file, buf, count, &pos); if (ret >= 0) file_pos_write(f.file, pos); fdput_pos(f); } return ret; } SYSCALL_DEFINE4(pread64, unsigned int, fd, char __user *, buf, size_t, count, loff_t, pos) { struct fd f; ssize_t ret = -EBADF; if (pos < 0) return -EINVAL; f = fdget(fd); if (f.file) { ret = -ESPIPE; if (f.file->f_mode & FMODE_PREAD) ret = vfs_read(f.file, buf, count, &pos); fdput(f); } return ret; } SYSCALL_DEFINE4(pwrite64, unsigned int, fd, const char __user *, buf, size_t, count, loff_t, pos) { struct fd f; ssize_t ret = -EBADF; if (pos < 0) return -EINVAL; f = fdget(fd); if (f.file) { ret = -ESPIPE; if (f.file->f_mode & FMODE_PWRITE) ret = vfs_write(f.file, buf, count, &pos); fdput(f); } return ret; } /* * Reduce an iovec's length in-place. Return the resulting number of segments */ unsigned long iov_shorten(struct iovec *iov, unsigned long nr_segs, size_t to) { unsigned long seg = 0; size_t len = 0; while (seg < nr_segs) { seg++; if (len + iov->iov_len >= to) { iov->iov_len = to - len; break; } len += iov->iov_len; iov++; } return seg; } EXPORT_SYMBOL(iov_shorten); static ssize_t do_iter_readv_writev(struct file *filp, struct iov_iter *iter, loff_t *ppos, iter_fn_t fn) { struct kiocb kiocb; ssize_t ret; init_sync_kiocb(&kiocb, filp); kiocb.ki_pos = *ppos; ret = fn(&kiocb, iter); BUG_ON(ret == -EIOCBQUEUED); *ppos = kiocb.ki_pos; return ret; } static ssize_t do_sync_readv_writev(struct file *filp, struct iov_iter *iter, loff_t *ppos, iov_fn_t fn) { struct kiocb kiocb; ssize_t ret; init_sync_kiocb(&kiocb, filp); kiocb.ki_pos = *ppos; ret = fn(&kiocb, iter->iov, iter->nr_segs, kiocb.ki_pos); BUG_ON(ret == -EIOCBQUEUED); *ppos = kiocb.ki_pos; return ret; } /* Do it by hand, with file-ops */ static ssize_t do_loop_readv_writev(struct file *filp, struct iov_iter *iter, loff_t *ppos, io_fn_t fn) { ssize_t ret = 0; while (iov_iter_count(iter)) { struct iovec iovec = iov_iter_iovec(iter); ssize_t nr; nr = fn(filp, iovec.iov_base, iovec.iov_len, ppos); if (nr < 0) { if (!ret) ret = nr; break; } ret += nr; if (nr != iovec.iov_len) break; iov_iter_advance(iter, nr); } return ret; } /* A write operation does a read from user space and vice versa */ #define vrfy_dir(type) ((type) == READ ? VERIFY_WRITE : VERIFY_READ) ssize_t rw_copy_check_uvector(int type, const struct iovec __user * uvector, unsigned long nr_segs, unsigned long fast_segs, struct iovec *fast_pointer, struct iovec **ret_pointer) { unsigned long seg; ssize_t ret; struct iovec *iov = fast_pointer; /* * SuS says "The readv() function *may* fail if the iovcnt argument * was less than or equal to 0, or greater than {IOV_MAX}. Linux has * traditionally returned zero for zero segments, so... */ if (nr_segs == 0) { ret = 0; goto out; } /* * First get the "struct iovec" from user memory and * verify all the pointers */ if (nr_segs > UIO_MAXIOV) { ret = -EINVAL; goto out; } if (nr_segs > fast_segs) { iov = kmalloc(nr_segs*sizeof(struct iovec), GFP_KERNEL); if (iov == NULL) { ret = -ENOMEM; goto out; } } if (copy_from_user(iov, uvector, nr_segs*sizeof(*uvector))) { ret = -EFAULT; goto out; } /* * According to the Single Unix Specification we should return EINVAL * if an element length is < 0 when cast to ssize_t or if the * total length would overflow the ssize_t return value of the * system call. * * Linux caps all read/write calls to MAX_RW_COUNT, and avoids the * overflow case. */ ret = 0; for (seg = 0; seg < nr_segs; seg++) { void __user *buf = iov[seg].iov_base; ssize_t len = (ssize_t)iov[seg].iov_len; /* see if we we're about to use an invalid len or if * it's about to overflow ssize_t */ if (len < 0) { ret = -EINVAL; goto out; } if (type >= 0 && unlikely(!access_ok(vrfy_dir(type), buf, len))) { ret = -EFAULT; goto out; } if (len > MAX_RW_COUNT - ret) { len = MAX_RW_COUNT - ret; iov[seg].iov_len = len; } ret += len; } out: *ret_pointer = iov; return ret; } static ssize_t do_readv_writev(int type, struct file *file, const struct iovec __user * uvector, unsigned long nr_segs, loff_t *pos) { size_t tot_len; struct iovec iovstack[UIO_FASTIOV]; struct iovec *iov = iovstack; struct iov_iter iter; ssize_t ret; io_fn_t fn; iov_fn_t fnv; iter_fn_t iter_fn; ret = import_iovec(type, uvector, nr_segs, ARRAY_SIZE(iovstack), &iov, &iter); if (ret < 0) return ret; tot_len = iov_iter_count(&iter); if (!tot_len) goto out; ret = rw_verify_area(type, file, pos, tot_len); if (ret < 0) goto out; fnv = NULL; if (type == READ) { fn = file->f_op->read; fnv = file->f_op->aio_read; iter_fn = file->f_op->read_iter; } else { fn = (io_fn_t)file->f_op->write; fnv = file->f_op->aio_write; iter_fn = file->f_op->write_iter; file_start_write(file); } if (iter_fn) ret = do_iter_readv_writev(file, &iter, pos, iter_fn); else if (fnv) ret = do_sync_readv_writev(file, &iter, pos, fnv); else ret = do_loop_readv_writev(file, &iter, pos, fn); if (type != READ) file_end_write(file); out: kfree(iov); if ((ret + (type == READ)) > 0) { if (type == READ) fsnotify_access(file); else fsnotify_modify(file); } return ret; } ssize_t vfs_readv(struct file *file, const struct iovec __user *vec, unsigned long vlen, loff_t *pos) { if (!(file->f_mode & FMODE_READ)) return -EBADF; if (!(file->f_mode & FMODE_CAN_READ)) return -EINVAL; return do_readv_writev(READ, file, vec, vlen, pos); } EXPORT_SYMBOL(vfs_readv); ssize_t vfs_writev(struct file *file, const struct iovec __user *vec, unsigned long vlen, loff_t *pos) { if (!(file->f_mode & FMODE_WRITE)) return -EBADF; if (!(file->f_mode & FMODE_CAN_WRITE)) return -EINVAL; return do_readv_writev(WRITE, file, vec, vlen, pos); } EXPORT_SYMBOL(vfs_writev); SYSCALL_DEFINE3(readv, unsigned long, fd, const struct iovec __user *, vec, unsigned long, vlen) { struct fd f = fdget_pos(fd); ssize_t ret = -EBADF; if (f.file) { loff_t pos = file_pos_read(f.file); ret = vfs_readv(f.file, vec, vlen, &pos); if (ret >= 0) file_pos_write(f.file, pos); fdput_pos(f); } if (ret > 0) add_rchar(current, ret); inc_syscr(current); return ret; } SYSCALL_DEFINE3(writev, unsigned long, fd, const struct iovec __user *, vec, unsigned long, vlen) { struct fd f = fdget_pos(fd); ssize_t ret = -EBADF; if (f.file) { loff_t pos = file_pos_read(f.file); ret = vfs_writev(f.file, vec, vlen, &pos); if (ret >= 0) file_pos_write(f.file, pos); fdput_pos(f); } if (ret > 0) add_wchar(current, ret); inc_syscw(current); return ret; } static inline loff_t pos_from_hilo(unsigned long high, unsigned long low) { #define HALF_LONG_BITS (BITS_PER_LONG / 2) return (((loff_t)high << HALF_LONG_BITS) << HALF_LONG_BITS) | low; } SYSCALL_DEFINE5(preadv, unsigned long, fd, const struct iovec __user *, vec, unsigned long, vlen, unsigned long, pos_l, unsigned long, pos_h) { loff_t pos = pos_from_hilo(pos_h, pos_l); struct fd f; ssize_t ret = -EBADF; if (pos < 0) return -EINVAL; f = fdget(fd); if (f.file) { ret = -ESPIPE; if (f.file->f_mode & FMODE_PREAD) ret = vfs_readv(f.file, vec, vlen, &pos); fdput(f); } if (ret > 0) add_rchar(current, ret); inc_syscr(current); return ret; } SYSCALL_DEFINE5(pwritev, unsigned long, fd, const struct iovec __user *, vec, unsigned long, vlen, unsigned long, pos_l, unsigned long, pos_h) { loff_t pos = pos_from_hilo(pos_h, pos_l); struct fd f; ssize_t ret = -EBADF; if (pos < 0) return -EINVAL; f = fdget(fd); if (f.file) { ret = -ESPIPE; if (f.file->f_mode & FMODE_PWRITE) ret = vfs_writev(f.file, vec, vlen, &pos); fdput(f); } if (ret > 0) add_wchar(current, ret); inc_syscw(current); return ret; } #ifdef CONFIG_COMPAT static ssize_t compat_do_readv_writev(int type, struct file *file, const struct compat_iovec __user *uvector, unsigned long nr_segs, loff_t *pos) { compat_ssize_t tot_len; struct iovec iovstack[UIO_FASTIOV]; struct iovec *iov = iovstack; struct iov_iter iter; ssize_t ret; io_fn_t fn; iov_fn_t fnv; iter_fn_t iter_fn; ret = compat_import_iovec(type, uvector, nr_segs, UIO_FASTIOV, &iov, &iter); if (ret < 0) return ret; tot_len = iov_iter_count(&iter); if (!tot_len) goto out; ret = rw_verify_area(type, file, pos, tot_len); if (ret < 0) goto out; fnv = NULL; if (type == READ) { fn = file->f_op->read; fnv = file->f_op->aio_read; iter_fn = file->f_op->read_iter; } else { fn = (io_fn_t)file->f_op->write; fnv = file->f_op->aio_write; iter_fn = file->f_op->write_iter; file_start_write(file); } if (iter_fn) ret = do_iter_readv_writev(file, &iter, pos, iter_fn); else if (fnv) ret = do_sync_readv_writev(file, &iter, pos, fnv); else ret = do_loop_readv_writev(file, &iter, pos, fn); if (type != READ) file_end_write(file); out: kfree(iov); if ((ret + (type == READ)) > 0) { if (type == READ) fsnotify_access(file); else fsnotify_modify(file); } return ret; } static size_t compat_readv(struct file *file, const struct compat_iovec __user *vec, unsigned long vlen, loff_t *pos) { ssize_t ret = -EBADF; if (!(file->f_mode & FMODE_READ)) goto out; ret = -EINVAL; if (!(file->f_mode & FMODE_CAN_READ)) goto out; ret = compat_do_readv_writev(READ, file, vec, vlen, pos); out: if (ret > 0) add_rchar(current, ret); inc_syscr(current); return ret; } COMPAT_SYSCALL_DEFINE3(readv, compat_ulong_t, fd, const struct compat_iovec __user *,vec, compat_ulong_t, vlen) { struct fd f = fdget_pos(fd); ssize_t ret; loff_t pos; if (!f.file) return -EBADF; pos = f.file->f_pos; ret = compat_readv(f.file, vec, vlen, &pos); if (ret >= 0) f.file->f_pos = pos; fdput_pos(f); return ret; } static long __compat_sys_preadv64(unsigned long fd, const struct compat_iovec __user *vec, unsigned long vlen, loff_t pos) { struct fd f; ssize_t ret; if (pos < 0) return -EINVAL; f = fdget(fd); if (!f.file) return -EBADF; ret = -ESPIPE; if (f.file->f_mode & FMODE_PREAD) ret = compat_readv(f.file, vec, vlen, &pos); fdput(f); return ret; } #ifdef __ARCH_WANT_COMPAT_SYS_PREADV64 COMPAT_SYSCALL_DEFINE4(preadv64, unsigned long, fd, const struct compat_iovec __user *,vec, unsigned long, vlen, loff_t, pos) { return __compat_sys_preadv64(fd, vec, vlen, pos); } #endif COMPAT_SYSCALL_DEFINE5(preadv, compat_ulong_t, fd, const struct compat_iovec __user *,vec, compat_ulong_t, vlen, u32, pos_low, u32, pos_high) { loff_t pos = ((loff_t)pos_high << 32) | pos_low; return __compat_sys_preadv64(fd, vec, vlen, pos); } static size_t compat_writev(struct file *file, const struct compat_iovec __user *vec, unsigned long vlen, loff_t *pos) { ssize_t ret = -EBADF; if (!(file->f_mode & FMODE_WRITE)) goto out; ret = -EINVAL; if (!(file->f_mode & FMODE_CAN_WRITE)) goto out; ret = compat_do_readv_writev(WRITE, file, vec, vlen, pos); out: if (ret > 0) add_wchar(current, ret); inc_syscw(current); return ret; } COMPAT_SYSCALL_DEFINE3(writev, compat_ulong_t, fd, const struct compat_iovec __user *, vec, compat_ulong_t, vlen) { struct fd f = fdget_pos(fd); ssize_t ret; loff_t pos; if (!f.file) return -EBADF; pos = f.file->f_pos; ret = compat_writev(f.file, vec, vlen, &pos); if (ret >= 0) f.file->f_pos = pos; fdput_pos(f); return ret; } static long __compat_sys_pwritev64(unsigned long fd, const struct compat_iovec __user *vec, unsigned long vlen, loff_t pos) { struct fd f; ssize_t ret; if (pos < 0) return -EINVAL; f = fdget(fd); if (!f.file) return -EBADF; ret = -ESPIPE; if (f.file->f_mode & FMODE_PWRITE) ret = compat_writev(f.file, vec, vlen, &pos); fdput(f); return ret; } #ifdef __ARCH_WANT_COMPAT_SYS_PWRITEV64 COMPAT_SYSCALL_DEFINE4(pwritev64, unsigned long, fd, const struct compat_iovec __user *,vec, unsigned long, vlen, loff_t, pos) { return __compat_sys_pwritev64(fd, vec, vlen, pos); } #endif COMPAT_SYSCALL_DEFINE5(pwritev, compat_ulong_t, fd, const struct compat_iovec __user *,vec, compat_ulong_t, vlen, u32, pos_low, u32, pos_high) { loff_t pos = ((loff_t)pos_high << 32) | pos_low; return __compat_sys_pwritev64(fd, vec, vlen, pos); } #endif static ssize_t do_sendfile(int out_fd, int in_fd, loff_t *ppos, size_t count, loff_t max) { struct fd in, out; struct inode *in_inode, *out_inode; loff_t pos; loff_t out_pos; ssize_t retval; int fl; /* * Get input file, and verify that it is ok.. */ retval = -EBADF; in = fdget(in_fd); if (!in.file) goto out; if (!(in.file->f_mode & FMODE_READ)) goto fput_in; retval = -ESPIPE; if (!ppos) { pos = in.file->f_pos; } else { pos = *ppos; if (!(in.file->f_mode & FMODE_PREAD)) goto fput_in; } retval = rw_verify_area(READ, in.file, &pos, count); if (retval < 0) goto fput_in; count = retval; /* * Get output file, and verify that it is ok.. */ retval = -EBADF; out = fdget(out_fd); if (!out.file) goto fput_in; if (!(out.file->f_mode & FMODE_WRITE)) goto fput_out; retval = -EINVAL; in_inode = file_inode(in.file); out_inode = file_inode(out.file); out_pos = out.file->f_pos; retval = rw_verify_area(WRITE, out.file, &out_pos, count); if (retval < 0) goto fput_out; count = retval; if (!max) max = min(in_inode->i_sb->s_maxbytes, out_inode->i_sb->s_maxbytes); if (unlikely(pos + count > max)) { retval = -EOVERFLOW; if (pos >= max) goto fput_out; count = max - pos; } fl = 0; #if 0 /* * We need to debate whether we can enable this or not. The * man page documents EAGAIN return for the output at least, * and the application is arguably buggy if it doesn't expect * EAGAIN on a non-blocking file descriptor. */ if (in.file->f_flags & O_NONBLOCK) fl = SPLICE_F_NONBLOCK; #endif file_start_write(out.file); retval = do_splice_direct(in.file, &pos, out.file, &out_pos, count, fl); file_end_write(out.file); if (retval > 0) { add_rchar(current, retval); add_wchar(current, retval); fsnotify_access(in.file); fsnotify_modify(out.file); out.file->f_pos = out_pos; if (ppos) *ppos = pos; else in.file->f_pos = pos; } inc_syscr(current); inc_syscw(current); if (pos > max) retval = -EOVERFLOW; fput_out: fdput(out); fput_in: fdput(in); out: return retval; } SYSCALL_DEFINE4(sendfile, int, out_fd, int, in_fd, off_t __user *, offset, size_t, count) { loff_t pos; off_t off; ssize_t ret; if (offset) { if (unlikely(get_user(off, offset))) return -EFAULT; pos = off; ret = do_sendfile(out_fd, in_fd, &pos, count, MAX_NON_LFS); if (unlikely(put_user(pos, offset))) return -EFAULT; return ret; } return do_sendfile(out_fd, in_fd, NULL, count, 0); } SYSCALL_DEFINE4(sendfile64, int, out_fd, int, in_fd, loff_t __user *, offset, size_t, count) { loff_t pos; ssize_t ret; if (offset) { if (unlikely(copy_from_user(&pos, offset, sizeof(loff_t)))) return -EFAULT; ret = do_sendfile(out_fd, in_fd, &pos, count, 0); if (unlikely(put_user(pos, offset))) return -EFAULT; return ret; } return do_sendfile(out_fd, in_fd, NULL, count, 0); } #ifdef CONFIG_COMPAT COMPAT_SYSCALL_DEFINE4(sendfile, int, out_fd, int, in_fd, compat_off_t __user *, offset, compat_size_t, count) { loff_t pos; off_t off; ssize_t ret; if (offset) { if (unlikely(get_user(off, offset))) return -EFAULT; pos = off; ret = do_sendfile(out_fd, in_fd, &pos, count, MAX_NON_LFS); if (unlikely(put_user(pos, offset))) return -EFAULT; return ret; } return do_sendfile(out_fd, in_fd, NULL, count, 0); } COMPAT_SYSCALL_DEFINE4(sendfile64, int, out_fd, int, in_fd, compat_loff_t __user *, offset, compat_size_t, count) { loff_t pos; ssize_t ret; if (offset) { if (unlikely(copy_from_user(&pos, offset, sizeof(loff_t)))) return -EFAULT; ret = do_sendfile(out_fd, in_fd, &pos, count, 0); if (unlikely(put_user(pos, offset))) return -EFAULT; return ret; } return do_sendfile(out_fd, in_fd, NULL, count, 0); } #endif