--- /dev/null
+/*
+ * linux/fs/file.c
+ *
+ * Copyright (C) 1998-1999, Stephen Tweedie and Bill Hawes
+ *
+ * Manage the dynamic fd arrays in the process files_struct.
+ */
+
+#include <linux/syscalls.h>
+#include <linux/export.h>
+#include <linux/fs.h>
+#include <linux/mm.h>
+#include <linux/mmzone.h>
+#include <linux/time.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+#include <linux/vmalloc.h>
+#include <linux/file.h>
+#include <linux/fdtable.h>
+#include <linux/bitops.h>
+#include <linux/interrupt.h>
+#include <linux/spinlock.h>
+#include <linux/rcupdate.h>
+#include <linux/workqueue.h>
+
+int sysctl_nr_open __read_mostly = 1024*1024;
+int sysctl_nr_open_min = BITS_PER_LONG;
+/* our max() is unusable in constant expressions ;-/ */
+#define __const_max(x, y) ((x) < (y) ? (x) : (y))
+int sysctl_nr_open_max = __const_max(INT_MAX, ~(size_t)0/sizeof(void *)) &
+ -BITS_PER_LONG;
+
+static void *alloc_fdmem(size_t size)
+{
+ /*
+ * Very large allocations can stress page reclaim, so fall back to
+ * vmalloc() if the allocation size will be considered "large" by the VM.
+ */
+ if (size <= (PAGE_SIZE << PAGE_ALLOC_COSTLY_ORDER)) {
+ void *data = kmalloc(size, GFP_KERNEL|__GFP_NOWARN|__GFP_NORETRY);
+ if (data != NULL)
+ return data;
+ }
+ return vmalloc(size);
+}
+
+static void __free_fdtable(struct fdtable *fdt)
+{
+ kvfree(fdt->fd);
+ kvfree(fdt->open_fds);
+ kfree(fdt);
+}
+
+static void free_fdtable_rcu(struct rcu_head *rcu)
+{
+ __free_fdtable(container_of(rcu, struct fdtable, rcu));
+}
+
+/*
+ * Expand the fdset in the files_struct. Called with the files spinlock
+ * held for write.
+ */
+static void copy_fdtable(struct fdtable *nfdt, struct fdtable *ofdt)
+{
+ unsigned int cpy, set;
+
+ BUG_ON(nfdt->max_fds < ofdt->max_fds);
+
+ cpy = ofdt->max_fds * sizeof(struct file *);
+ set = (nfdt->max_fds - ofdt->max_fds) * sizeof(struct file *);
+ memcpy(nfdt->fd, ofdt->fd, cpy);
+ memset((char *)(nfdt->fd) + cpy, 0, set);
+
+ cpy = ofdt->max_fds / BITS_PER_BYTE;
+ set = (nfdt->max_fds - ofdt->max_fds) / BITS_PER_BYTE;
+ memcpy(nfdt->open_fds, ofdt->open_fds, cpy);
+ memset((char *)(nfdt->open_fds) + cpy, 0, set);
+ memcpy(nfdt->close_on_exec, ofdt->close_on_exec, cpy);
+ memset((char *)(nfdt->close_on_exec) + cpy, 0, set);
+}
+
+static struct fdtable * alloc_fdtable(unsigned int nr)
+{
+ struct fdtable *fdt;
+ void *data;
+
+ /*
+ * Figure out how many fds we actually want to support in this fdtable.
+ * Allocation steps are keyed to the size of the fdarray, since it
+ * grows far faster than any of the other dynamic data. We try to fit
+ * the fdarray into comfortable page-tuned chunks: starting at 1024B
+ * and growing in powers of two from there on.
+ */
+ nr /= (1024 / sizeof(struct file *));
+ nr = roundup_pow_of_two(nr + 1);
+ nr *= (1024 / sizeof(struct file *));
+ /*
+ * Note that this can drive nr *below* what we had passed if sysctl_nr_open
+ * had been set lower between the check in expand_files() and here. Deal
+ * with that in caller, it's cheaper that way.
+ *
+ * We make sure that nr remains a multiple of BITS_PER_LONG - otherwise
+ * bitmaps handling below becomes unpleasant, to put it mildly...
+ */
+ if (unlikely(nr > sysctl_nr_open))
+ nr = ((sysctl_nr_open - 1) | (BITS_PER_LONG - 1)) + 1;
+
+ fdt = kmalloc(sizeof(struct fdtable), GFP_KERNEL);
+ if (!fdt)
+ goto out;
+ fdt->max_fds = nr;
+ data = alloc_fdmem(nr * sizeof(struct file *));
+ if (!data)
+ goto out_fdt;
+ fdt->fd = data;
+
+ data = alloc_fdmem(max_t(size_t,
+ 2 * nr / BITS_PER_BYTE, L1_CACHE_BYTES));
+ if (!data)
+ goto out_arr;
+ fdt->open_fds = data;
+ data += nr / BITS_PER_BYTE;
+ fdt->close_on_exec = data;
+
+ return fdt;
+
+out_arr:
+ kvfree(fdt->fd);
+out_fdt:
+ kfree(fdt);
+out:
+ return NULL;
+}
+
+/*
+ * Expand the file descriptor table.
+ * This function will allocate a new fdtable and both fd array and fdset, of
+ * the given size.
+ * Return <0 error code on error; 1 on successful completion.
+ * The files->file_lock should be held on entry, and will be held on exit.
+ */
+static int expand_fdtable(struct files_struct *files, int nr)
+ __releases(files->file_lock)
+ __acquires(files->file_lock)
+{
+ struct fdtable *new_fdt, *cur_fdt;
+
+ spin_unlock(&files->file_lock);
+ new_fdt = alloc_fdtable(nr);
+ spin_lock(&files->file_lock);
+ if (!new_fdt)
+ return -ENOMEM;
+ /*
+ * extremely unlikely race - sysctl_nr_open decreased between the check in
+ * caller and alloc_fdtable(). Cheaper to catch it here...
+ */
+ if (unlikely(new_fdt->max_fds <= nr)) {
+ __free_fdtable(new_fdt);
+ return -EMFILE;
+ }
+ /*
+ * Check again since another task may have expanded the fd table while
+ * we dropped the lock
+ */
+ cur_fdt = files_fdtable(files);
+ if (nr >= cur_fdt->max_fds) {
+ /* Continue as planned */
+ copy_fdtable(new_fdt, cur_fdt);
+ rcu_assign_pointer(files->fdt, new_fdt);
+ if (cur_fdt != &files->fdtab)
+ call_rcu(&cur_fdt->rcu, free_fdtable_rcu);
+ } else {
+ /* Somebody else expanded, so undo our attempt */
+ __free_fdtable(new_fdt);
+ }
+ return 1;
+}
+
+/*
+ * Expand files.
+ * This function will expand the file structures, if the requested size exceeds
+ * the current capacity and there is room for expansion.
+ * Return <0 error code on error; 0 when nothing done; 1 when files were
+ * expanded and execution may have blocked.
+ * The files->file_lock should be held on entry, and will be held on exit.
+ */
+static int expand_files(struct files_struct *files, int nr)
+{
+ struct fdtable *fdt;
+
+ fdt = files_fdtable(files);
+
+ /* Do we need to expand? */
+ if (nr < fdt->max_fds)
+ return 0;
+
+ /* Can we expand? */
+ if (nr >= sysctl_nr_open)
+ return -EMFILE;
+
+ /* All good, so we try */
+ return expand_fdtable(files, nr);
+}
+
+static inline void __set_close_on_exec(int fd, struct fdtable *fdt)
+{
+ __set_bit(fd, fdt->close_on_exec);
+}
+
+static inline void __clear_close_on_exec(int fd, struct fdtable *fdt)
+{
+ __clear_bit(fd, fdt->close_on_exec);
+}
+
+static inline void __set_open_fd(int fd, struct fdtable *fdt)
+{
+ __set_bit(fd, fdt->open_fds);
+}
+
+static inline void __clear_open_fd(int fd, struct fdtable *fdt)
+{
+ __clear_bit(fd, fdt->open_fds);
+}
+
+static int count_open_files(struct fdtable *fdt)
+{
+ int size = fdt->max_fds;
+ int i;
+
+ /* Find the last open fd */
+ for (i = size / BITS_PER_LONG; i > 0; ) {
+ if (fdt->open_fds[--i])
+ break;
+ }
+ i = (i + 1) * BITS_PER_LONG;
+ return i;
+}
+
+/*
+ * Allocate a new files structure and copy contents from the
+ * passed in files structure.
+ * errorp will be valid only when the returned files_struct is NULL.
+ */
+struct files_struct *dup_fd(struct files_struct *oldf, int *errorp)
+{
+ struct files_struct *newf;
+ struct file **old_fds, **new_fds;
+ int open_files, size, i;
+ struct fdtable *old_fdt, *new_fdt;
+
+ *errorp = -ENOMEM;
+ newf = kmem_cache_alloc(files_cachep, GFP_KERNEL);
+ if (!newf)
+ goto out;
+
+ atomic_set(&newf->count, 1);
+
+ spin_lock_init(&newf->file_lock);
+ newf->next_fd = 0;
+ new_fdt = &newf->fdtab;
+ new_fdt->max_fds = NR_OPEN_DEFAULT;
+ new_fdt->close_on_exec = newf->close_on_exec_init;
+ new_fdt->open_fds = newf->open_fds_init;
+ new_fdt->fd = &newf->fd_array[0];
+
+ spin_lock(&oldf->file_lock);
+ old_fdt = files_fdtable(oldf);
+ open_files = count_open_files(old_fdt);
+
+ /*
+ * Check whether we need to allocate a larger fd array and fd set.
+ */
+ while (unlikely(open_files > new_fdt->max_fds)) {
+ spin_unlock(&oldf->file_lock);
+
+ if (new_fdt != &newf->fdtab)
+ __free_fdtable(new_fdt);
+
+ new_fdt = alloc_fdtable(open_files - 1);
+ if (!new_fdt) {
+ *errorp = -ENOMEM;
+ goto out_release;
+ }
+
+ /* beyond sysctl_nr_open; nothing to do */
+ if (unlikely(new_fdt->max_fds < open_files)) {
+ __free_fdtable(new_fdt);
+ *errorp = -EMFILE;
+ goto out_release;
+ }
+
+ /*
+ * Reacquire the oldf lock and a pointer to its fd table
+ * who knows it may have a new bigger fd table. We need
+ * the latest pointer.
+ */
+ spin_lock(&oldf->file_lock);
+ old_fdt = files_fdtable(oldf);
+ open_files = count_open_files(old_fdt);
+ }
+
+ old_fds = old_fdt->fd;
+ new_fds = new_fdt->fd;
+
+ memcpy(new_fdt->open_fds, old_fdt->open_fds, open_files / 8);
+ memcpy(new_fdt->close_on_exec, old_fdt->close_on_exec, open_files / 8);
+
+ for (i = open_files; i != 0; i--) {
+ struct file *f = *old_fds++;
+ if (f) {
+ get_file(f);
+ } else {
+ /*
+ * The fd may be claimed in the fd bitmap but not yet
+ * instantiated in the files array if a sibling thread
+ * is partway through open(). So make sure that this
+ * fd is available to the new process.
+ */
+ __clear_open_fd(open_files - i, new_fdt);
+ }
+ rcu_assign_pointer(*new_fds++, f);
+ }
+ spin_unlock(&oldf->file_lock);
+
+ /* compute the remainder to be cleared */
+ size = (new_fdt->max_fds - open_files) * sizeof(struct file *);
+
+ /* This is long word aligned thus could use a optimized version */
+ memset(new_fds, 0, size);
+
+ if (new_fdt->max_fds > open_files) {
+ int left = (new_fdt->max_fds - open_files) / 8;
+ int start = open_files / BITS_PER_LONG;
+
+ memset(&new_fdt->open_fds[start], 0, left);
+ memset(&new_fdt->close_on_exec[start], 0, left);
+ }
+
+ rcu_assign_pointer(newf->fdt, new_fdt);
+
+ return newf;
+
+out_release:
+ kmem_cache_free(files_cachep, newf);
+out:
+ return NULL;
+}
+
+static struct fdtable *close_files(struct files_struct * files)
+{
+ /*
+ * It is safe to dereference the fd table without RCU or
+ * ->file_lock because this is the last reference to the
+ * files structure.
+ */
+ struct fdtable *fdt = rcu_dereference_raw(files->fdt);
+ int i, j = 0;
+
+ for (;;) {
+ unsigned long set;
+ i = j * BITS_PER_LONG;
+ if (i >= fdt->max_fds)
+ break;
+ set = fdt->open_fds[j++];
+ while (set) {
+ if (set & 1) {
+ struct file * file = xchg(&fdt->fd[i], NULL);
+ if (file) {
+ filp_close(file, files);
+ cond_resched_rcu_qs();
+ }
+ }
+ i++;
+ set >>= 1;
+ }
+ }
+
+ return fdt;
+}
+
+struct files_struct *get_files_struct(struct task_struct *task)
+{
+ struct files_struct *files;
+
+ task_lock(task);
+ files = task->files;
+ if (files)
+ atomic_inc(&files->count);
+ task_unlock(task);
+
+ return files;
+}
+
+void put_files_struct(struct files_struct *files)
+{
+ if (atomic_dec_and_test(&files->count)) {
+ struct fdtable *fdt = close_files(files);
+
+ /* free the arrays if they are not embedded */
+ if (fdt != &files->fdtab)
+ __free_fdtable(fdt);
+ kmem_cache_free(files_cachep, files);
+ }
+}
+
+void reset_files_struct(struct files_struct *files)
+{
+ struct task_struct *tsk = current;
+ struct files_struct *old;
+
+ old = tsk->files;
+ task_lock(tsk);
+ tsk->files = files;
+ task_unlock(tsk);
+ put_files_struct(old);
+}
+
+void exit_files(struct task_struct *tsk)
+{
+ struct files_struct * files = tsk->files;
+
+ if (files) {
+ task_lock(tsk);
+ tsk->files = NULL;
+ task_unlock(tsk);
+ put_files_struct(files);
+ }
+}
+
+struct files_struct init_files = {
+ .count = ATOMIC_INIT(1),
+ .fdt = &init_files.fdtab,
+ .fdtab = {
+ .max_fds = NR_OPEN_DEFAULT,
+ .fd = &init_files.fd_array[0],
+ .close_on_exec = init_files.close_on_exec_init,
+ .open_fds = init_files.open_fds_init,
+ },
+ .file_lock = __SPIN_LOCK_UNLOCKED(init_files.file_lock),
+};
+
+/*
+ * allocate a file descriptor, mark it busy.
+ */
+int __alloc_fd(struct files_struct *files,
+ unsigned start, unsigned end, unsigned flags)
+{
+ unsigned int fd;
+ int error;
+ struct fdtable *fdt;
+
+ spin_lock(&files->file_lock);
+repeat:
+ fdt = files_fdtable(files);
+ fd = start;
+ if (fd < files->next_fd)
+ fd = files->next_fd;
+
+ if (fd < fdt->max_fds)
+ fd = find_next_zero_bit(fdt->open_fds, fdt->max_fds, fd);
+
+ /*
+ * N.B. For clone tasks sharing a files structure, this test
+ * will limit the total number of files that can be opened.
+ */
+ error = -EMFILE;
+ if (fd >= end)
+ goto out;
+
+ error = expand_files(files, fd);
+ if (error < 0)
+ goto out;
+
+ /*
+ * If we needed to expand the fs array we
+ * might have blocked - try again.
+ */
+ if (error)
+ goto repeat;
+
+ if (start <= files->next_fd)
+ files->next_fd = fd + 1;
+
+ __set_open_fd(fd, fdt);
+ if (flags & O_CLOEXEC)
+ __set_close_on_exec(fd, fdt);
+ else
+ __clear_close_on_exec(fd, fdt);
+ error = fd;
+#if 1
+ /* Sanity check */
+ if (rcu_access_pointer(fdt->fd[fd]) != NULL) {
+ printk(KERN_WARNING "alloc_fd: slot %d not NULL!\n", fd);
+ rcu_assign_pointer(fdt->fd[fd], NULL);
+ }
+#endif
+
+out:
+ spin_unlock(&files->file_lock);
+ return error;
+}
+
+static int alloc_fd(unsigned start, unsigned flags)
+{
+ return __alloc_fd(current->files, start, rlimit(RLIMIT_NOFILE), flags);
+}
+
+int get_unused_fd_flags(unsigned flags)
+{
+ return __alloc_fd(current->files, 0, rlimit(RLIMIT_NOFILE), flags);
+}
+EXPORT_SYMBOL(get_unused_fd_flags);
+
+static void __put_unused_fd(struct files_struct *files, unsigned int fd)
+{
+ struct fdtable *fdt = files_fdtable(files);
+ __clear_open_fd(fd, fdt);
+ if (fd < files->next_fd)
+ files->next_fd = fd;
+}
+
+void put_unused_fd(unsigned int fd)
+{
+ struct files_struct *files = current->files;
+ spin_lock(&files->file_lock);
+ __put_unused_fd(files, fd);
+ spin_unlock(&files->file_lock);
+}
+
+EXPORT_SYMBOL(put_unused_fd);
+
+/*
+ * Install a file pointer in the fd array.
+ *
+ * The VFS is full of places where we drop the files lock between
+ * setting the open_fds bitmap and installing the file in the file
+ * array. At any such point, we are vulnerable to a dup2() race
+ * installing a file in the array before us. We need to detect this and
+ * fput() the struct file we are about to overwrite in this case.
+ *
+ * It should never happen - if we allow dup2() do it, _really_ bad things
+ * will follow.
+ *
+ * NOTE: __fd_install() variant is really, really low-level; don't
+ * use it unless you are forced to by truly lousy API shoved down
+ * your throat. 'files' *MUST* be either current->files or obtained
+ * by get_files_struct(current) done by whoever had given it to you,
+ * or really bad things will happen. Normally you want to use
+ * fd_install() instead.
+ */
+
+void __fd_install(struct files_struct *files, unsigned int fd,
+ struct file *file)
+{
+ struct fdtable *fdt;
+ spin_lock(&files->file_lock);
+ fdt = files_fdtable(files);
+ BUG_ON(fdt->fd[fd] != NULL);
+ rcu_assign_pointer(fdt->fd[fd], file);
+ spin_unlock(&files->file_lock);
+}
+
+void fd_install(unsigned int fd, struct file *file)
+{
+ __fd_install(current->files, fd, file);
+}
+
+EXPORT_SYMBOL(fd_install);
+
+/*
+ * The same warnings as for __alloc_fd()/__fd_install() apply here...
+ */
+int __close_fd(struct files_struct *files, unsigned fd)
+{
+ struct file *file;
+ struct fdtable *fdt;
+
+ spin_lock(&files->file_lock);
+ fdt = files_fdtable(files);
+ if (fd >= fdt->max_fds)
+ goto out_unlock;
+ file = fdt->fd[fd];
+ if (!file)
+ goto out_unlock;
+ rcu_assign_pointer(fdt->fd[fd], NULL);
+ __clear_close_on_exec(fd, fdt);
+ __put_unused_fd(files, fd);
+ spin_unlock(&files->file_lock);
+ return filp_close(file, files);
+
+out_unlock:
+ spin_unlock(&files->file_lock);
+ return -EBADF;
+}
+
+void do_close_on_exec(struct files_struct *files)
+{
+ unsigned i;
+ struct fdtable *fdt;
+
+ /* exec unshares first */
+ spin_lock(&files->file_lock);
+ for (i = 0; ; i++) {
+ unsigned long set;
+ unsigned fd = i * BITS_PER_LONG;
+ fdt = files_fdtable(files);
+ if (fd >= fdt->max_fds)
+ break;
+ set = fdt->close_on_exec[i];
+ if (!set)
+ continue;
+ fdt->close_on_exec[i] = 0;
+ for ( ; set ; fd++, set >>= 1) {
+ struct file *file;
+ if (!(set & 1))
+ continue;
+ file = fdt->fd[fd];
+ if (!file)
+ continue;
+ rcu_assign_pointer(fdt->fd[fd], NULL);
+ __put_unused_fd(files, fd);
+ spin_unlock(&files->file_lock);
+ filp_close(file, files);
+ cond_resched();
+ spin_lock(&files->file_lock);
+ }
+
+ }
+ spin_unlock(&files->file_lock);
+}
+
+static struct file *__fget(unsigned int fd, fmode_t mask)
+{
+ struct files_struct *files = current->files;
+ struct file *file;
+
+ rcu_read_lock();
+ file = fcheck_files(files, fd);
+ if (file) {
+ /* File object ref couldn't be taken */
+ if ((file->f_mode & mask) || !get_file_rcu(file))
+ file = NULL;
+ }
+ rcu_read_unlock();
+
+ return file;
+}
+
+struct file *fget(unsigned int fd)
+{
+ return __fget(fd, FMODE_PATH);
+}
+EXPORT_SYMBOL(fget);
+
+struct file *fget_raw(unsigned int fd)
+{
+ return __fget(fd, 0);
+}
+EXPORT_SYMBOL(fget_raw);
+
+/*
+ * Lightweight file lookup - no refcnt increment if fd table isn't shared.
+ *
+ * You can use this instead of fget if you satisfy all of the following
+ * conditions:
+ * 1) You must call fput_light before exiting the syscall and returning control
+ * to userspace (i.e. you cannot remember the returned struct file * after
+ * returning to userspace).
+ * 2) You must not call filp_close on the returned struct file * in between
+ * calls to fget_light and fput_light.
+ * 3) You must not clone the current task in between the calls to fget_light
+ * and fput_light.
+ *
+ * The fput_needed flag returned by fget_light should be passed to the
+ * corresponding fput_light.
+ */
+static unsigned long __fget_light(unsigned int fd, fmode_t mask)
+{
+ struct files_struct *files = current->files;
+ struct file *file;
+
+ if (atomic_read(&files->count) == 1) {
+ file = __fcheck_files(files, fd);
+ if (!file || unlikely(file->f_mode & mask))
+ return 0;
+ return (unsigned long)file;
+ } else {
+ file = __fget(fd, mask);
+ if (!file)
+ return 0;
+ return FDPUT_FPUT | (unsigned long)file;
+ }
+}
+unsigned long __fdget(unsigned int fd)
+{
+ return __fget_light(fd, FMODE_PATH);
+}
+EXPORT_SYMBOL(__fdget);
+
+unsigned long __fdget_raw(unsigned int fd)
+{
+ return __fget_light(fd, 0);
+}
+
+unsigned long __fdget_pos(unsigned int fd)
+{
+ unsigned long v = __fdget(fd);
+ struct file *file = (struct file *)(v & ~3);
+
+ if (file && (file->f_mode & FMODE_ATOMIC_POS)) {
+ if (file_count(file) > 1) {
+ v |= FDPUT_POS_UNLOCK;
+ mutex_lock(&file->f_pos_lock);
+ }
+ }
+ return v;
+}
+
+/*
+ * We only lock f_pos if we have threads or if the file might be
+ * shared with another process. In both cases we'll have an elevated
+ * file count (done either by fdget() or by fork()).
+ */
+
+void set_close_on_exec(unsigned int fd, int flag)
+{
+ struct files_struct *files = current->files;
+ struct fdtable *fdt;
+ spin_lock(&files->file_lock);
+ fdt = files_fdtable(files);
+ if (flag)
+ __set_close_on_exec(fd, fdt);
+ else
+ __clear_close_on_exec(fd, fdt);
+ spin_unlock(&files->file_lock);
+}
+
+bool get_close_on_exec(unsigned int fd)
+{
+ struct files_struct *files = current->files;
+ struct fdtable *fdt;
+ bool res;
+ rcu_read_lock();
+ fdt = files_fdtable(files);
+ res = close_on_exec(fd, fdt);
+ rcu_read_unlock();
+ return res;
+}
+
+static int do_dup2(struct files_struct *files,
+ struct file *file, unsigned fd, unsigned flags)
+__releases(&files->file_lock)
+{
+ struct file *tofree;
+ struct fdtable *fdt;
+
+ /*
+ * We need to detect attempts to do dup2() over allocated but still
+ * not finished descriptor. NB: OpenBSD avoids that at the price of
+ * extra work in their equivalent of fget() - they insert struct
+ * file immediately after grabbing descriptor, mark it larval if
+ * more work (e.g. actual opening) is needed and make sure that
+ * fget() treats larval files as absent. Potentially interesting,
+ * but while extra work in fget() is trivial, locking implications
+ * and amount of surgery on open()-related paths in VFS are not.
+ * FreeBSD fails with -EBADF in the same situation, NetBSD "solution"
+ * deadlocks in rather amusing ways, AFAICS. All of that is out of
+ * scope of POSIX or SUS, since neither considers shared descriptor
+ * tables and this condition does not arise without those.
+ */
+ fdt = files_fdtable(files);
+ tofree = fdt->fd[fd];
+ if (!tofree && fd_is_open(fd, fdt))
+ goto Ebusy;
+ get_file(file);
+ rcu_assign_pointer(fdt->fd[fd], file);
+ __set_open_fd(fd, fdt);
+ if (flags & O_CLOEXEC)
+ __set_close_on_exec(fd, fdt);
+ else
+ __clear_close_on_exec(fd, fdt);
+ spin_unlock(&files->file_lock);
+
+ if (tofree)
+ filp_close(tofree, files);
+
+ return fd;
+
+Ebusy:
+ spin_unlock(&files->file_lock);
+ return -EBUSY;
+}
+
+int replace_fd(unsigned fd, struct file *file, unsigned flags)
+{
+ int err;
+ struct files_struct *files = current->files;
+
+ if (!file)
+ return __close_fd(files, fd);
+
+ if (fd >= rlimit(RLIMIT_NOFILE))
+ return -EBADF;
+
+ spin_lock(&files->file_lock);
+ err = expand_files(files, fd);
+ if (unlikely(err < 0))
+ goto out_unlock;
+ return do_dup2(files, file, fd, flags);
+
+out_unlock:
+ spin_unlock(&files->file_lock);
+ return err;
+}
+
+SYSCALL_DEFINE3(dup3, unsigned int, oldfd, unsigned int, newfd, int, flags)
+{
+ int err = -EBADF;
+ struct file *file;
+ struct files_struct *files = current->files;
+
+ if ((flags & ~O_CLOEXEC) != 0)
+ return -EINVAL;
+
+ if (unlikely(oldfd == newfd))
+ return -EINVAL;
+
+ if (newfd >= rlimit(RLIMIT_NOFILE))
+ return -EBADF;
+
+ spin_lock(&files->file_lock);
+ err = expand_files(files, newfd);
+ file = fcheck(oldfd);
+ if (unlikely(!file))
+ goto Ebadf;
+ if (unlikely(err < 0)) {
+ if (err == -EMFILE)
+ goto Ebadf;
+ goto out_unlock;
+ }
+ return do_dup2(files, file, newfd, flags);
+
+Ebadf:
+ err = -EBADF;
+out_unlock:
+ spin_unlock(&files->file_lock);
+ return err;
+}
+
+SYSCALL_DEFINE2(dup2, unsigned int, oldfd, unsigned int, newfd)
+{
+ if (unlikely(newfd == oldfd)) { /* corner case */
+ struct files_struct *files = current->files;
+ int retval = oldfd;
+
+ rcu_read_lock();
+ if (!fcheck_files(files, oldfd))
+ retval = -EBADF;
+ rcu_read_unlock();
+ return retval;
+ }
+ return sys_dup3(oldfd, newfd, 0);
+}
+
+SYSCALL_DEFINE1(dup, unsigned int, fildes)
+{
+ int ret = -EBADF;
+ struct file *file = fget_raw(fildes);
+
+ if (file) {
+ ret = get_unused_fd_flags(0);
+ if (ret >= 0)
+ fd_install(ret, file);
+ else
+ fput(file);
+ }
+ return ret;
+}
+
+int f_dupfd(unsigned int from, struct file *file, unsigned flags)
+{
+ int err;
+ if (from >= rlimit(RLIMIT_NOFILE))
+ return -EINVAL;
+ err = alloc_fd(from, flags);
+ if (err >= 0) {
+ get_file(file);
+ fd_install(err, file);
+ }
+ return err;
+}
+
+int iterate_fd(struct files_struct *files, unsigned n,
+ int (*f)(const void *, struct file *, unsigned),
+ const void *p)
+{
+ struct fdtable *fdt;
+ int res = 0;
+ if (!files)
+ return 0;
+ spin_lock(&files->file_lock);
+ for (fdt = files_fdtable(files); n < fdt->max_fds; n++) {
+ struct file *file;
+ file = rcu_dereference_check_fdtable(files, fdt->fd[n]);
+ if (!file)
+ continue;
+ res = f(p, file, n);
+ if (res)
+ break;
+ }
+ spin_unlock(&files->file_lock);
+ return res;
+}
+EXPORT_SYMBOL(iterate_fd);
Code Review / kvmfornfv.git / blobdiff