diff options
author | André Fabian Silva Delgado <emulatorman@parabola.nu> | 2015-08-05 17:04:01 -0300 |
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committer | André Fabian Silva Delgado <emulatorman@parabola.nu> | 2015-08-05 17:04:01 -0300 |
commit | 57f0f512b273f60d52568b8c6b77e17f5636edc0 (patch) | |
tree | 5e910f0e82173f4ef4f51111366a3f1299037a7b /fs/read_write.c |
Initial import
Diffstat (limited to 'fs/read_write.c')
-rw-r--r-- | fs/read_write.c | 1353 |
1 files changed, 1353 insertions, 0 deletions
diff --git a/fs/read_write.c b/fs/read_write.c new file mode 100644 index 000000000..8ace6ec15 --- /dev/null +++ b/fs/read_write.c @@ -0,0 +1,1353 @@ +/* + * linux/fs/read_write.c + * + * Copyright (C) 1991, 1992 Linus Torvalds + */ + +#include <linux/slab.h> +#include <linux/stat.h> +#include <linux/fcntl.h> +#include <linux/file.h> +#include <linux/uio.h> +#include <linux/fsnotify.h> +#include <linux/security.h> +#include <linux/export.h> +#include <linux/syscalls.h> +#include <linux/pagemap.h> +#include <linux/splice.h> +#include <linux/compat.h> +#include "internal.h" + +#include <asm/uaccess.h> +#include <asm/unistd.h> + +typedef ssize_t (*io_fn_t)(struct file *, char __user *, size_t, 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_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; +} + +static 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; +} + +ssize_t __vfs_read(struct file *file, char __user *buf, size_t count, + loff_t *pos) +{ + if (file->f_op->read) + return file->f_op->read(file, buf, count, pos); + else if (file->f_op->read_iter) + return new_sync_read(file, buf, count, pos); + else + return -EINVAL; +} +EXPORT_SYMBOL(__vfs_read); + +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); + +static 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); + if (ret > 0) + *ppos = kiocb.ki_pos; + return ret; +} + +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->write_iter) + return new_sync_write(file, p, count, pos); + else + return -EINVAL; +} +EXPORT_SYMBOL(__vfs_write); + +vfs_readf_t vfs_readf(struct file *file) +{ + const struct file_operations *fop = file->f_op; + + if (fop->read) + return fop->read; + if (fop->read_iter) + return new_sync_read; + return ERR_PTR(-ENOSYS); +} +EXPORT_SYMBOL(vfs_readf); + +vfs_writef_t vfs_writef(struct file *file) +{ + const struct file_operations *fop = file->f_op; + + if (fop->write) + return fop->write; + if (fop->write_iter) + return new_sync_write; + return ERR_PTR(-ENOSYS); +} +EXPORT_SYMBOL(vfs_writef); + +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; +} + +/* 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; + 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; + + if (type == READ) { + fn = file->f_op->read; + iter_fn = file->f_op->read_iter; + } else { + fn = (io_fn_t)file->f_op->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 + 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; + 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; + + if (type == READ) { + fn = file->f_op->read; + iter_fn = file->f_op->read_iter; + } else { + fn = (io_fn_t)file->f_op->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 + 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 |