123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178179180181182183184185186187188189190191192193194195196197198199200201202203204205206207208209210211212213214215216217218219220221222223224225226227228229230231232233234235236237238239240241242243244245246247248249250251252253254255256257258259260261262263264265266267268269270271272273274275276277278279280281282283284285286287288289290291292293294295296297298299300301302303304305306307308309310311312313314315316317318319320321322323324325326327328329330331332333334335336337338339340341342343344345346347348349350351352353354355356357358359360361362363364365366367368369370371372373374375376377378379380381382383384385386387388389390391392393394395396397398399400401402403404405406407408409410411412413414415416417418419420421422423424425426427428429430431432433434435436437438439440441442443444445446447448449450451452453454455456457458459460461462463464465466467468469470471472473474475476477478479480481482483484485486487488489490491492493494495496497498499500501502503504505506507508509510511512513514515516517518519520521522523524525526527528529530531532533534535536537538539540541542543544545546547548549550551552553554555556557558559560561562563564565566567568569570571572573574575576577578579580581582583584585586587588589590591592593594595596597598599600601602603604605606607608609610611612613614615616617618619620621622623624625626627628629630631632633634635636637638639640641642643644645646647648649650651652653654655656657658659660661662663664665666667668669670671672673674675676677678679680681682683684685686687688689690691692693694695696697698699700701702703704705706707708709710711712713714715716717718719720721722723724725726727728729730731732733734735736737738739740741742743744745746747748749750751752753754755756757758759760761762763764765766767768769770771772773774775776777778779780781782783784785786787788789790791792793794795796797798799800801802803804805806807808809810811812813814815816817818819820821822823824825826827828829830831832833834835836837838839840841842843844845846847848849850851852853854855856857858859860861862863864865866867868869870871872873874875876877878879880881882883884885886887888889890891892893894895896897898899900901902903904905906907908909910911912913914915916917918919920921922923924925926927928929930931932933934935936937938939940941942943944945946947948949950951952953954955956957958959960961962963964965966967968969970971972973974975976977978979980981982983984985986987988989990991992993994995996997998999100010011002100310041005100610071008100910101011101210131014101510161017101810191020102110221023102410251026102710281029103010311032103310341035103610371038103910401041104210431044104510461047104810491050105110521053105410551056105710581059106010611062106310641065106610671068106910701071107210731074107510761077107810791080108110821083108410851086108710881089109010911092109310941095109610971098109911001101110211031104110511061107110811091110111111121113111411151116111711181119112011211122112311241125112611271128112911301131113211331134113511361137113811391140114111421143114411451146114711481149115011511152115311541155115611571158115911601161116211631164116511661167116811691170117111721173117411751176117711781179118011811182118311841185118611871188118911901191119211931194119511961197119811991200120112021203120412051206120712081209121012111212121312141215121612171218121912201221122212231224122512261227122812291230123112321233123412351236123712381239124012411242124312441245124612471248124912501251125212531254125512561257125812591260126112621263126412651266126712681269127012711272127312741275127612771278127912801281128212831284128512861287128812891290129112921293129412951296129712981299130013011302130313041305130613071308130913101311131213131314131513161317131813191320132113221323132413251326132713281329133013311332133313341335133613371338133913401341134213431344134513461347134813491350135113521353135413551356135713581359136013611362136313641365136613671368136913701371137213731374137513761377137813791380138113821383138413851386138713881389139013911392139313941395139613971398139914001401140214031404140514061407140814091410141114121413141414151416141714181419142014211422142314241425142614271428142914301431143214331434143514361437143814391440144114421443144414451446144714481449145014511452145314541455145614571458145914601461146214631464146514661467146814691470147114721473147414751476147714781479148014811482148314841485148614871488148914901491149214931494149514961497149814991500150115021503150415051506150715081509151015111512151315141515151615171518151915201521152215231524152515261527152815291530153115321533153415351536153715381539154015411542154315441545154615471548154915501551155215531554155515561557155815591560156115621563156415651566156715681569157015711572157315741575157615771578157915801581158215831584158515861587158815891590159115921593159415951596159715981599160016011602160316041605160616071608160916101611161216131614161516161617161816191620162116221623162416251626162716281629163016311632163316341635163616371638163916401641164216431644164516461647164816491650165116521653165416551656165716581659166016611662166316641665166616671668166916701671167216731674167516761677167816791680168116821683168416851686 |
- // SPDX-License-Identifier: GPL-2.0
- /*
- * linux/fs/read_write.c
- *
- * Copyright (C) 1991, 1992 Linus Torvalds
- */
- #include <linux/slab.h>
- #include <linux/stat.h>
- #include <linux/sched/xacct.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 <linux/mount.h>
- #include <linux/fs.h>
- #include "internal.h"
- #include <linux/uaccess.h>
- #include <asm/unistd.h>
- 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 bool 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 ((unsigned long long)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 ((unsigned long long)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);
- /**
- * no_seek_end_llseek - llseek implementation for fixed-sized devices
- * @file: file structure to seek on
- * @offset: file offset to seek to
- * @whence: type of seek
- *
- */
- loff_t no_seek_end_llseek(struct file *file, loff_t offset, int whence)
- {
- switch (whence) {
- case SEEK_SET: case SEEK_CUR:
- return generic_file_llseek_size(file, offset, whence,
- OFFSET_MAX, 0);
- default:
- return -EINVAL;
- }
- }
- EXPORT_SYMBOL(no_seek_end_llseek);
- /**
- * no_seek_end_llseek_size - llseek implementation for fixed-sized devices
- * @file: file structure to seek on
- * @offset: file offset to seek to
- * @whence: type of seek
- * @size: maximal offset allowed
- *
- */
- loff_t no_seek_end_llseek_size(struct file *file, loff_t offset, int whence, loff_t size)
- {
- switch (whence) {
- case SEEK_SET: case SEEK_CUR:
- return generic_file_llseek_size(file, offset, whence,
- size, 0);
- default:
- return -EINVAL;
- }
- }
- EXPORT_SYMBOL(no_seek_end_llseek_size);
- /**
- * 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;
- inode_lock(inode);
- 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:
- inode_unlock(inode);
- 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 off_t ksys_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;
- }
- SYSCALL_DEFINE3(lseek, unsigned int, fd, off_t, offset, unsigned int, whence)
- {
- return ksys_lseek(fd, offset, whence);
- }
- #ifdef CONFIG_COMPAT
- COMPAT_SYSCALL_DEFINE3(lseek, unsigned int, fd, compat_off_t, offset, unsigned int, whence)
- {
- return ksys_lseek(fd, offset, whence);
- }
- #endif
- #if !defined(CONFIG_64BIT) || defined(CONFIG_COMPAT) || \
- defined(__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
- int rw_verify_area(int read_write, struct file *file, const loff_t *ppos, size_t count)
- {
- struct inode *inode;
- int retval = -EINVAL;
- inode = file_inode(file);
- if (unlikely((ssize_t) count < 0))
- return retval;
- /*
- * ranged mandatory locking does not apply to streams - it makes sense
- * only for files where position has a meaning.
- */
- if (ppos) {
- loff_t 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(inode, file, pos, pos + count - 1,
- read_write == READ ? F_RDLCK : F_WRLCK);
- if (retval < 0)
- return retval;
- }
- }
- return security_file_permission(file,
- read_write == READ ? MAY_READ : MAY_WRITE);
- }
- 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 ? *ppos : 0);
- iov_iter_init(&iter, READ, &iov, 1, len);
- ret = call_read_iter(filp, &kiocb, &iter);
- BUG_ON(ret == -EIOCBQUEUED);
- if (ppos)
- *ppos = kiocb.ki_pos;
- return ret;
- }
- static int warn_unsupported(struct file *file, const char *op)
- {
- pr_warn_ratelimited(
- "kernel %s not supported for file %pD4 (pid: %d comm: %.20s)\n",
- op, file, current->pid, current->comm);
- return -EINVAL;
- }
- ssize_t __kernel_read(struct file *file, void *buf, size_t count, loff_t *pos)
- {
- struct kvec iov = {
- .iov_base = buf,
- .iov_len = min_t(size_t, count, MAX_RW_COUNT),
- };
- struct kiocb kiocb;
- struct iov_iter iter;
- ssize_t ret;
- if (WARN_ON_ONCE(!(file->f_mode & FMODE_READ)))
- return -EINVAL;
- if (!(file->f_mode & FMODE_CAN_READ))
- return -EINVAL;
- /*
- * Also fail if ->read_iter and ->read are both wired up as that
- * implies very convoluted semantics.
- */
- if (unlikely(!file->f_op->read_iter || file->f_op->read))
- return warn_unsupported(file, "read");
- init_sync_kiocb(&kiocb, file);
- kiocb.ki_pos = pos ? *pos : 0;
- iov_iter_kvec(&iter, READ, &iov, 1, iov.iov_len);
- ret = file->f_op->read_iter(&kiocb, &iter);
- if (ret > 0) {
- if (pos)
- *pos = kiocb.ki_pos;
- fsnotify_access(file);
- add_rchar(current, ret);
- }
- inc_syscr(current);
- return ret;
- }
- ssize_t kernel_read(struct file *file, void *buf, size_t count, loff_t *pos)
- {
- ssize_t ret;
- ret = rw_verify_area(READ, file, pos, count);
- if (ret)
- return ret;
- return __kernel_read(file, buf, count, pos);
- }
- EXPORT_SYMBOL_NS(kernel_read, ANDROID_GKI_VFS_EXPORT_ONLY);
- 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(buf, count)))
- return -EFAULT;
- ret = rw_verify_area(READ, file, pos, count);
- if (ret)
- return ret;
- if (count > MAX_RW_COUNT)
- count = MAX_RW_COUNT;
- if (file->f_op->read)
- ret = file->f_op->read(file, buf, count, pos);
- else if (file->f_op->read_iter)
- ret = new_sync_read(file, buf, count, pos);
- else
- ret = -EINVAL;
- if (ret > 0) {
- fsnotify_access(file);
- add_rchar(current, ret);
- }
- inc_syscr(current);
- return ret;
- }
- 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 ? *ppos : 0);
- iov_iter_init(&iter, WRITE, &iov, 1, len);
- ret = call_write_iter(filp, &kiocb, &iter);
- BUG_ON(ret == -EIOCBQUEUED);
- if (ret > 0 && ppos)
- *ppos = kiocb.ki_pos;
- return ret;
- }
- /* caller is responsible for file_start_write/file_end_write */
- ssize_t __kernel_write(struct file *file, const void *buf, size_t count, loff_t *pos)
- {
- struct kvec iov = {
- .iov_base = (void *)buf,
- .iov_len = min_t(size_t, count, MAX_RW_COUNT),
- };
- struct kiocb kiocb;
- struct iov_iter iter;
- ssize_t ret;
- if (WARN_ON_ONCE(!(file->f_mode & FMODE_WRITE)))
- return -EBADF;
- if (!(file->f_mode & FMODE_CAN_WRITE))
- return -EINVAL;
- /*
- * Also fail if ->write_iter and ->write are both wired up as that
- * implies very convoluted semantics.
- */
- if (unlikely(!file->f_op->write_iter || file->f_op->write))
- return warn_unsupported(file, "write");
- init_sync_kiocb(&kiocb, file);
- kiocb.ki_pos = pos ? *pos : 0;
- iov_iter_kvec(&iter, WRITE, &iov, 1, iov.iov_len);
- ret = file->f_op->write_iter(&kiocb, &iter);
- if (ret > 0) {
- if (pos)
- *pos = kiocb.ki_pos;
- fsnotify_modify(file);
- add_wchar(current, ret);
- }
- inc_syscw(current);
- return ret;
- }
- /*
- * This "EXPORT_SYMBOL_GPL()" is more of a "EXPORT_SYMBOL_DONTUSE()",
- * but autofs is one of the few internal kernel users that actually
- * wants this _and_ can be built as a module. So we need to export
- * this symbol for autofs, even though it really isn't appropriate
- * for any other kernel modules.
- */
- EXPORT_SYMBOL_GPL(__kernel_write);
- ssize_t kernel_write(struct file *file, const void *buf, size_t count,
- loff_t *pos)
- {
- ssize_t ret;
- ret = rw_verify_area(WRITE, file, pos, count);
- if (ret)
- return ret;
- file_start_write(file);
- ret = __kernel_write(file, buf, count, pos);
- file_end_write(file);
- return ret;
- }
- EXPORT_SYMBOL_NS(kernel_write, ANDROID_GKI_VFS_EXPORT_ONLY);
- 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(buf, count)))
- return -EFAULT;
- ret = rw_verify_area(WRITE, file, pos, count);
- if (ret)
- return ret;
- if (count > MAX_RW_COUNT)
- count = MAX_RW_COUNT;
- file_start_write(file);
- if (file->f_op->write)
- ret = file->f_op->write(file, buf, count, pos);
- else if (file->f_op->write_iter)
- ret = new_sync_write(file, buf, count, pos);
- else
- ret = -EINVAL;
- if (ret > 0) {
- fsnotify_modify(file);
- add_wchar(current, ret);
- }
- inc_syscw(current);
- file_end_write(file);
- return ret;
- }
- /* file_ppos returns &file->f_pos or NULL if file is stream */
- static inline loff_t *file_ppos(struct file *file)
- {
- return file->f_mode & FMODE_STREAM ? NULL : &file->f_pos;
- }
- ssize_t ksys_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, *ppos = file_ppos(f.file);
- if (ppos) {
- pos = *ppos;
- ppos = &pos;
- }
- ret = vfs_read(f.file, buf, count, ppos);
- if (ret >= 0 && ppos)
- f.file->f_pos = pos;
- fdput_pos(f);
- }
- return ret;
- }
- SYSCALL_DEFINE3(read, unsigned int, fd, char __user *, buf, size_t, count)
- {
- return ksys_read(fd, buf, count);
- }
- ssize_t ksys_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, *ppos = file_ppos(f.file);
- if (ppos) {
- pos = *ppos;
- ppos = &pos;
- }
- ret = vfs_write(f.file, buf, count, ppos);
- if (ret >= 0 && ppos)
- f.file->f_pos = pos;
- fdput_pos(f);
- }
- return ret;
- }
- SYSCALL_DEFINE3(write, unsigned int, fd, const char __user *, buf,
- size_t, count)
- {
- return ksys_write(fd, buf, count);
- }
- ssize_t ksys_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(pread64, unsigned int, fd, char __user *, buf,
- size_t, count, loff_t, pos)
- {
- return ksys_pread64(fd, buf, count, pos);
- }
- ssize_t ksys_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;
- }
- SYSCALL_DEFINE4(pwrite64, unsigned int, fd, const char __user *, buf,
- size_t, count, loff_t, pos)
- {
- return ksys_pwrite64(fd, buf, count, pos);
- }
- static ssize_t do_iter_readv_writev(struct file *filp, struct iov_iter *iter,
- loff_t *ppos, int type, rwf_t flags)
- {
- struct kiocb kiocb;
- ssize_t ret;
- init_sync_kiocb(&kiocb, filp);
- ret = kiocb_set_rw_flags(&kiocb, flags);
- if (ret)
- return ret;
- kiocb.ki_pos = (ppos ? *ppos : 0);
- if (type == READ)
- ret = call_read_iter(filp, &kiocb, iter);
- else
- ret = call_write_iter(filp, &kiocb, iter);
- BUG_ON(ret == -EIOCBQUEUED);
- if (ppos)
- *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, int type, rwf_t flags)
- {
- ssize_t ret = 0;
- if (flags & ~RWF_HIPRI)
- return -EOPNOTSUPP;
- while (iov_iter_count(iter)) {
- struct iovec iovec = iov_iter_iovec(iter);
- ssize_t nr;
- if (type == READ) {
- nr = filp->f_op->read(filp, iovec.iov_base,
- iovec.iov_len, ppos);
- } else {
- nr = filp->f_op->write(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;
- }
- static ssize_t do_iter_read(struct file *file, struct iov_iter *iter,
- loff_t *pos, rwf_t flags)
- {
- size_t tot_len;
- ssize_t ret = 0;
- if (!(file->f_mode & FMODE_READ))
- return -EBADF;
- if (!(file->f_mode & FMODE_CAN_READ))
- return -EINVAL;
- tot_len = iov_iter_count(iter);
- if (!tot_len)
- goto out;
- ret = rw_verify_area(READ, file, pos, tot_len);
- if (ret < 0)
- return ret;
- if (file->f_op->read_iter)
- ret = do_iter_readv_writev(file, iter, pos, READ, flags);
- else
- ret = do_loop_readv_writev(file, iter, pos, READ, flags);
- out:
- if (ret >= 0)
- fsnotify_access(file);
- return ret;
- }
- ssize_t vfs_iocb_iter_read(struct file *file, struct kiocb *iocb,
- struct iov_iter *iter)
- {
- size_t tot_len;
- ssize_t ret = 0;
- if (!file->f_op->read_iter)
- return -EINVAL;
- if (!(file->f_mode & FMODE_READ))
- return -EBADF;
- if (!(file->f_mode & FMODE_CAN_READ))
- return -EINVAL;
- tot_len = iov_iter_count(iter);
- if (!tot_len)
- goto out;
- ret = rw_verify_area(READ, file, &iocb->ki_pos, tot_len);
- if (ret < 0)
- return ret;
- ret = call_read_iter(file, iocb, iter);
- out:
- if (ret >= 0)
- fsnotify_access(file);
- return ret;
- }
- EXPORT_SYMBOL(vfs_iocb_iter_read);
- ssize_t vfs_iter_read(struct file *file, struct iov_iter *iter, loff_t *ppos,
- rwf_t flags)
- {
- if (!file->f_op->read_iter)
- return -EINVAL;
- return do_iter_read(file, iter, ppos, flags);
- }
- EXPORT_SYMBOL(vfs_iter_read);
- static ssize_t do_iter_write(struct file *file, struct iov_iter *iter,
- loff_t *pos, rwf_t flags)
- {
- size_t tot_len;
- ssize_t ret = 0;
- if (!(file->f_mode & FMODE_WRITE))
- return -EBADF;
- if (!(file->f_mode & FMODE_CAN_WRITE))
- return -EINVAL;
- tot_len = iov_iter_count(iter);
- if (!tot_len)
- return 0;
- ret = rw_verify_area(WRITE, file, pos, tot_len);
- if (ret < 0)
- return ret;
- if (file->f_op->write_iter)
- ret = do_iter_readv_writev(file, iter, pos, WRITE, flags);
- else
- ret = do_loop_readv_writev(file, iter, pos, WRITE, flags);
- if (ret > 0)
- fsnotify_modify(file);
- return ret;
- }
- ssize_t vfs_iocb_iter_write(struct file *file, struct kiocb *iocb,
- struct iov_iter *iter)
- {
- size_t tot_len;
- ssize_t ret = 0;
- if (!file->f_op->write_iter)
- return -EINVAL;
- if (!(file->f_mode & FMODE_WRITE))
- return -EBADF;
- if (!(file->f_mode & FMODE_CAN_WRITE))
- return -EINVAL;
- tot_len = iov_iter_count(iter);
- if (!tot_len)
- return 0;
- ret = rw_verify_area(WRITE, file, &iocb->ki_pos, tot_len);
- if (ret < 0)
- return ret;
- ret = call_write_iter(file, iocb, iter);
- if (ret > 0)
- fsnotify_modify(file);
- return ret;
- }
- EXPORT_SYMBOL(vfs_iocb_iter_write);
- ssize_t vfs_iter_write(struct file *file, struct iov_iter *iter, loff_t *ppos,
- rwf_t flags)
- {
- if (!file->f_op->write_iter)
- return -EINVAL;
- return do_iter_write(file, iter, ppos, flags);
- }
- EXPORT_SYMBOL(vfs_iter_write);
- static ssize_t vfs_readv(struct file *file, const struct iovec __user *vec,
- unsigned long vlen, loff_t *pos, rwf_t flags)
- {
- struct iovec iovstack[UIO_FASTIOV];
- struct iovec *iov = iovstack;
- struct iov_iter iter;
- ssize_t ret;
- ret = import_iovec(READ, vec, vlen, ARRAY_SIZE(iovstack), &iov, &iter);
- if (ret >= 0) {
- ret = do_iter_read(file, &iter, pos, flags);
- kfree(iov);
- }
- return ret;
- }
- static ssize_t vfs_writev(struct file *file, const struct iovec __user *vec,
- unsigned long vlen, loff_t *pos, rwf_t flags)
- {
- struct iovec iovstack[UIO_FASTIOV];
- struct iovec *iov = iovstack;
- struct iov_iter iter;
- ssize_t ret;
- ret = import_iovec(WRITE, vec, vlen, ARRAY_SIZE(iovstack), &iov, &iter);
- if (ret >= 0) {
- file_start_write(file);
- ret = do_iter_write(file, &iter, pos, flags);
- file_end_write(file);
- kfree(iov);
- }
- return ret;
- }
- static ssize_t do_readv(unsigned long fd, const struct iovec __user *vec,
- unsigned long vlen, rwf_t flags)
- {
- struct fd f = fdget_pos(fd);
- ssize_t ret = -EBADF;
- if (f.file) {
- loff_t pos, *ppos = file_ppos(f.file);
- if (ppos) {
- pos = *ppos;
- ppos = &pos;
- }
- ret = vfs_readv(f.file, vec, vlen, ppos, flags);
- if (ret >= 0 && ppos)
- f.file->f_pos = pos;
- fdput_pos(f);
- }
- if (ret > 0)
- add_rchar(current, ret);
- inc_syscr(current);
- return ret;
- }
- static ssize_t do_writev(unsigned long fd, const struct iovec __user *vec,
- unsigned long vlen, rwf_t flags)
- {
- struct fd f = fdget_pos(fd);
- ssize_t ret = -EBADF;
- if (f.file) {
- loff_t pos, *ppos = file_ppos(f.file);
- if (ppos) {
- pos = *ppos;
- ppos = &pos;
- }
- ret = vfs_writev(f.file, vec, vlen, ppos, flags);
- if (ret >= 0 && ppos)
- f.file->f_pos = 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;
- }
- static ssize_t do_preadv(unsigned long fd, const struct iovec __user *vec,
- unsigned long vlen, loff_t pos, rwf_t flags)
- {
- 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, flags);
- fdput(f);
- }
- if (ret > 0)
- add_rchar(current, ret);
- inc_syscr(current);
- return ret;
- }
- static ssize_t do_pwritev(unsigned long fd, const struct iovec __user *vec,
- unsigned long vlen, loff_t pos, rwf_t flags)
- {
- 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, flags);
- fdput(f);
- }
- if (ret > 0)
- add_wchar(current, ret);
- inc_syscw(current);
- return ret;
- }
- SYSCALL_DEFINE3(readv, unsigned long, fd, const struct iovec __user *, vec,
- unsigned long, vlen)
- {
- return do_readv(fd, vec, vlen, 0);
- }
- SYSCALL_DEFINE3(writev, unsigned long, fd, const struct iovec __user *, vec,
- unsigned long, vlen)
- {
- return do_writev(fd, vec, vlen, 0);
- }
- 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);
- return do_preadv(fd, vec, vlen, pos, 0);
- }
- SYSCALL_DEFINE6(preadv2, unsigned long, fd, const struct iovec __user *, vec,
- unsigned long, vlen, unsigned long, pos_l, unsigned long, pos_h,
- rwf_t, flags)
- {
- loff_t pos = pos_from_hilo(pos_h, pos_l);
- if (pos == -1)
- return do_readv(fd, vec, vlen, flags);
- return do_preadv(fd, vec, vlen, pos, flags);
- }
- 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);
- return do_pwritev(fd, vec, vlen, pos, 0);
- }
- SYSCALL_DEFINE6(pwritev2, unsigned long, fd, const struct iovec __user *, vec,
- unsigned long, vlen, unsigned long, pos_l, unsigned long, pos_h,
- rwf_t, flags)
- {
- loff_t pos = pos_from_hilo(pos_h, pos_l);
- if (pos == -1)
- return do_writev(fd, vec, vlen, flags);
- return do_pwritev(fd, vec, vlen, pos, flags);
- }
- /*
- * Various compat syscalls. Note that they all pretend to take a native
- * iovec - import_iovec will properly treat those as compat_iovecs based on
- * in_compat_syscall().
- */
- #ifdef CONFIG_COMPAT
- #ifdef __ARCH_WANT_COMPAT_SYS_PREADV64
- COMPAT_SYSCALL_DEFINE4(preadv64, unsigned long, fd,
- const struct iovec __user *, vec,
- unsigned long, vlen, loff_t, pos)
- {
- return do_preadv(fd, vec, vlen, pos, 0);
- }
- #endif
- COMPAT_SYSCALL_DEFINE5(preadv, compat_ulong_t, fd,
- const struct iovec __user *, vec,
- compat_ulong_t, vlen, u32, pos_low, u32, pos_high)
- {
- loff_t pos = ((loff_t)pos_high << 32) | pos_low;
- return do_preadv(fd, vec, vlen, pos, 0);
- }
- #ifdef __ARCH_WANT_COMPAT_SYS_PREADV64V2
- COMPAT_SYSCALL_DEFINE5(preadv64v2, unsigned long, fd,
- const struct iovec __user *, vec,
- unsigned long, vlen, loff_t, pos, rwf_t, flags)
- {
- if (pos == -1)
- return do_readv(fd, vec, vlen, flags);
- return do_preadv(fd, vec, vlen, pos, flags);
- }
- #endif
- COMPAT_SYSCALL_DEFINE6(preadv2, compat_ulong_t, fd,
- const struct iovec __user *, vec,
- compat_ulong_t, vlen, u32, pos_low, u32, pos_high,
- rwf_t, flags)
- {
- loff_t pos = ((loff_t)pos_high << 32) | pos_low;
- if (pos == -1)
- return do_readv(fd, vec, vlen, flags);
- return do_preadv(fd, vec, vlen, pos, flags);
- }
- #ifdef __ARCH_WANT_COMPAT_SYS_PWRITEV64
- COMPAT_SYSCALL_DEFINE4(pwritev64, unsigned long, fd,
- const struct iovec __user *, vec,
- unsigned long, vlen, loff_t, pos)
- {
- return do_pwritev(fd, vec, vlen, pos, 0);
- }
- #endif
- COMPAT_SYSCALL_DEFINE5(pwritev, compat_ulong_t, fd,
- const struct iovec __user *,vec,
- compat_ulong_t, vlen, u32, pos_low, u32, pos_high)
- {
- loff_t pos = ((loff_t)pos_high << 32) | pos_low;
- return do_pwritev(fd, vec, vlen, pos, 0);
- }
- #ifdef __ARCH_WANT_COMPAT_SYS_PWRITEV64V2
- COMPAT_SYSCALL_DEFINE5(pwritev64v2, unsigned long, fd,
- const struct iovec __user *, vec,
- unsigned long, vlen, loff_t, pos, rwf_t, flags)
- {
- if (pos == -1)
- return do_writev(fd, vec, vlen, flags);
- return do_pwritev(fd, vec, vlen, pos, flags);
- }
- #endif
- COMPAT_SYSCALL_DEFINE6(pwritev2, compat_ulong_t, fd,
- const struct iovec __user *,vec,
- compat_ulong_t, vlen, u32, pos_low, u32, pos_high, rwf_t, flags)
- {
- loff_t pos = ((loff_t)pos_high << 32) | pos_low;
- if (pos == -1)
- return do_writev(fd, vec, vlen, flags);
- return do_pwritev(fd, vec, vlen, pos, flags);
- }
- #endif /* CONFIG_COMPAT */
- 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;
- if (count > MAX_RW_COUNT)
- count = MAX_RW_COUNT;
- /*
- * 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;
- 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;
- 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
- /**
- * generic_copy_file_range - copy data between two files
- * @file_in: file structure to read from
- * @pos_in: file offset to read from
- * @file_out: file structure to write data to
- * @pos_out: file offset to write data to
- * @len: amount of data to copy
- * @flags: copy flags
- *
- * This is a generic filesystem helper to copy data from one file to another.
- * It has no constraints on the source or destination file owners - the files
- * can belong to different superblocks and different filesystem types. Short
- * copies are allowed.
- *
- * This should be called from the @file_out filesystem, as per the
- * ->copy_file_range() method.
- *
- * Returns the number of bytes copied or a negative error indicating the
- * failure.
- */
- ssize_t generic_copy_file_range(struct file *file_in, loff_t pos_in,
- struct file *file_out, loff_t pos_out,
- size_t len, unsigned int flags)
- {
- return do_splice_direct(file_in, &pos_in, file_out, &pos_out,
- len > MAX_RW_COUNT ? MAX_RW_COUNT : len, 0);
- }
- EXPORT_SYMBOL(generic_copy_file_range);
- static ssize_t do_copy_file_range(struct file *file_in, loff_t pos_in,
- struct file *file_out, loff_t pos_out,
- size_t len, unsigned int flags)
- {
- /*
- * Although we now allow filesystems to handle cross sb copy, passing
- * a file of the wrong filesystem type to filesystem driver can result
- * in an attempt to dereference the wrong type of ->private_data, so
- * avoid doing that until we really have a good reason. NFS defines
- * several different file_system_type structures, but they all end up
- * using the same ->copy_file_range() function pointer.
- */
- if (file_out->f_op->copy_file_range &&
- file_out->f_op->copy_file_range == file_in->f_op->copy_file_range)
- return file_out->f_op->copy_file_range(file_in, pos_in,
- file_out, pos_out,
- len, flags);
- return generic_copy_file_range(file_in, pos_in, file_out, pos_out, len,
- flags);
- }
- /*
- * Performs necessary checks before doing a file copy
- *
- * Can adjust amount of bytes to copy via @req_count argument.
- * Returns appropriate error code that caller should return or
- * zero in case the copy should be allowed.
- */
- static int generic_copy_file_checks(struct file *file_in, loff_t pos_in,
- struct file *file_out, loff_t pos_out,
- size_t *req_count, unsigned int flags)
- {
- struct inode *inode_in = file_inode(file_in);
- struct inode *inode_out = file_inode(file_out);
- uint64_t count = *req_count;
- loff_t size_in;
- int ret;
- ret = generic_file_rw_checks(file_in, file_out);
- if (ret)
- return ret;
- /* Don't touch certain kinds of inodes */
- if (IS_IMMUTABLE(inode_out))
- return -EPERM;
- if (IS_SWAPFILE(inode_in) || IS_SWAPFILE(inode_out))
- return -ETXTBSY;
- /* Ensure offsets don't wrap. */
- if (pos_in + count < pos_in || pos_out + count < pos_out)
- return -EOVERFLOW;
- /* Shorten the copy to EOF */
- size_in = i_size_read(inode_in);
- if (pos_in >= size_in)
- count = 0;
- else
- count = min(count, size_in - (uint64_t)pos_in);
- ret = generic_write_check_limits(file_out, pos_out, &count);
- if (ret)
- return ret;
- /* Don't allow overlapped copying within the same file. */
- if (inode_in == inode_out &&
- pos_out + count > pos_in &&
- pos_out < pos_in + count)
- return -EINVAL;
- *req_count = count;
- return 0;
- }
- /*
- * copy_file_range() differs from regular file read and write in that it
- * specifically allows return partial success. When it does so is up to
- * the copy_file_range method.
- */
- ssize_t vfs_copy_file_range(struct file *file_in, loff_t pos_in,
- struct file *file_out, loff_t pos_out,
- size_t len, unsigned int flags)
- {
- ssize_t ret;
- if (flags != 0)
- return -EINVAL;
- ret = generic_copy_file_checks(file_in, pos_in, file_out, pos_out, &len,
- flags);
- if (unlikely(ret))
- return ret;
- ret = rw_verify_area(READ, file_in, &pos_in, len);
- if (unlikely(ret))
- return ret;
- ret = rw_verify_area(WRITE, file_out, &pos_out, len);
- if (unlikely(ret))
- return ret;
- if (len == 0)
- return 0;
- file_start_write(file_out);
- /*
- * Try cloning first, this is supported by more file systems, and
- * more efficient if both clone and copy are supported (e.g. NFS).
- */
- if (file_in->f_op->remap_file_range &&
- file_inode(file_in)->i_sb == file_inode(file_out)->i_sb) {
- loff_t cloned;
- cloned = file_in->f_op->remap_file_range(file_in, pos_in,
- file_out, pos_out,
- min_t(loff_t, MAX_RW_COUNT, len),
- REMAP_FILE_CAN_SHORTEN);
- if (cloned > 0) {
- ret = cloned;
- goto done;
- }
- }
- ret = do_copy_file_range(file_in, pos_in, file_out, pos_out, len,
- flags);
- WARN_ON_ONCE(ret == -EOPNOTSUPP);
- done:
- if (ret > 0) {
- fsnotify_access(file_in);
- add_rchar(current, ret);
- fsnotify_modify(file_out);
- add_wchar(current, ret);
- }
- inc_syscr(current);
- inc_syscw(current);
- file_end_write(file_out);
- return ret;
- }
- EXPORT_SYMBOL(vfs_copy_file_range);
- SYSCALL_DEFINE6(copy_file_range, int, fd_in, loff_t __user *, off_in,
- int, fd_out, loff_t __user *, off_out,
- size_t, len, unsigned int, flags)
- {
- loff_t pos_in;
- loff_t pos_out;
- struct fd f_in;
- struct fd f_out;
- ssize_t ret = -EBADF;
- f_in = fdget(fd_in);
- if (!f_in.file)
- goto out2;
- f_out = fdget(fd_out);
- if (!f_out.file)
- goto out1;
- ret = -EFAULT;
- if (off_in) {
- if (copy_from_user(&pos_in, off_in, sizeof(loff_t)))
- goto out;
- } else {
- pos_in = f_in.file->f_pos;
- }
- if (off_out) {
- if (copy_from_user(&pos_out, off_out, sizeof(loff_t)))
- goto out;
- } else {
- pos_out = f_out.file->f_pos;
- }
- ret = vfs_copy_file_range(f_in.file, pos_in, f_out.file, pos_out, len,
- flags);
- if (ret > 0) {
- pos_in += ret;
- pos_out += ret;
- if (off_in) {
- if (copy_to_user(off_in, &pos_in, sizeof(loff_t)))
- ret = -EFAULT;
- } else {
- f_in.file->f_pos = pos_in;
- }
- if (off_out) {
- if (copy_to_user(off_out, &pos_out, sizeof(loff_t)))
- ret = -EFAULT;
- } else {
- f_out.file->f_pos = pos_out;
- }
- }
- out:
- fdput(f_out);
- out1:
- fdput(f_in);
- out2:
- return ret;
- }
- /*
- * Don't operate on ranges the page cache doesn't support, and don't exceed the
- * LFS limits. If pos is under the limit it becomes a short access. If it
- * exceeds the limit we return -EFBIG.
- */
- int generic_write_check_limits(struct file *file, loff_t pos, loff_t *count)
- {
- struct inode *inode = file->f_mapping->host;
- loff_t max_size = inode->i_sb->s_maxbytes;
- loff_t limit = rlimit(RLIMIT_FSIZE);
- if (limit != RLIM_INFINITY) {
- if (pos >= limit) {
- send_sig(SIGXFSZ, current, 0);
- return -EFBIG;
- }
- *count = min(*count, limit - pos);
- }
- if (!(file->f_flags & O_LARGEFILE))
- max_size = MAX_NON_LFS;
- if (unlikely(pos >= max_size))
- return -EFBIG;
- *count = min(*count, max_size - pos);
- return 0;
- }
- /*
- * Performs necessary checks before doing a write
- *
- * Can adjust writing position or amount of bytes to write.
- * Returns appropriate error code that caller should return or
- * zero in case that write should be allowed.
- */
- ssize_t generic_write_checks(struct kiocb *iocb, struct iov_iter *from)
- {
- struct file *file = iocb->ki_filp;
- struct inode *inode = file->f_mapping->host;
- loff_t count;
- int ret;
- if (IS_SWAPFILE(inode))
- return -ETXTBSY;
- if (!iov_iter_count(from))
- return 0;
- /* FIXME: this is for backwards compatibility with 2.4 */
- if (iocb->ki_flags & IOCB_APPEND)
- iocb->ki_pos = i_size_read(inode);
- if ((iocb->ki_flags & IOCB_NOWAIT) && !(iocb->ki_flags & IOCB_DIRECT))
- return -EINVAL;
- count = iov_iter_count(from);
- ret = generic_write_check_limits(file, iocb->ki_pos, &count);
- if (ret)
- return ret;
- iov_iter_truncate(from, count);
- return iov_iter_count(from);
- }
- EXPORT_SYMBOL(generic_write_checks);
- /*
- * Performs common checks before doing a file copy/clone
- * from @file_in to @file_out.
- */
- int generic_file_rw_checks(struct file *file_in, struct file *file_out)
- {
- struct inode *inode_in = file_inode(file_in);
- struct inode *inode_out = file_inode(file_out);
- /* Don't copy dirs, pipes, sockets... */
- if (S_ISDIR(inode_in->i_mode) || S_ISDIR(inode_out->i_mode))
- return -EISDIR;
- if (!S_ISREG(inode_in->i_mode) || !S_ISREG(inode_out->i_mode))
- return -EINVAL;
- if (!(file_in->f_mode & FMODE_READ) ||
- !(file_out->f_mode & FMODE_WRITE) ||
- (file_out->f_flags & O_APPEND))
- return -EBADF;
- return 0;
- }
|