summaryrefslogtreecommitdiffstats
path: root/fs/file.c
diff options
context:
space:
mode:
Diffstat (limited to 'fs/file.c')
-rw-r--r--fs/file.c121
1 files changed, 110 insertions, 11 deletions
diff --git a/fs/file.c b/fs/file.c
index 4fb111735d1d..4cb9ef4d8571 100644
--- a/fs/file.c
+++ b/fs/file.c
@@ -10,6 +10,7 @@
#include <linux/syscalls.h>
#include <linux/export.h>
#include <linux/fs.h>
+#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/sched/signal.h>
#include <linux/slab.h>
@@ -18,6 +19,7 @@
#include <linux/bitops.h>
#include <linux/spinlock.h>
#include <linux/rcupdate.h>
+#include <linux/close_range.h>
#include <net/sock.h>
unsigned int sysctl_nr_open __read_mostly = 1024*1024;
@@ -265,12 +267,22 @@ static unsigned int count_open_files(struct fdtable *fdt)
return i;
}
+static unsigned int sane_fdtable_size(struct fdtable *fdt, unsigned int max_fds)
+{
+ unsigned int count;
+
+ count = count_open_files(fdt);
+ if (max_fds < NR_OPEN_DEFAULT)
+ max_fds = NR_OPEN_DEFAULT;
+ return min(count, max_fds);
+}
+
/*
* 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 *dup_fd(struct files_struct *oldf, unsigned int max_fds, int *errorp)
{
struct files_struct *newf;
struct file **old_fds, **new_fds;
@@ -297,7 +309,7 @@ struct files_struct *dup_fd(struct files_struct *oldf, int *errorp)
spin_lock(&oldf->file_lock);
old_fdt = files_fdtable(oldf);
- open_files = count_open_files(old_fdt);
+ open_files = sane_fdtable_size(old_fdt, max_fds);
/*
* Check whether we need to allocate a larger fd array and fd set.
@@ -328,7 +340,7 @@ struct files_struct *dup_fd(struct files_struct *oldf, int *errorp)
*/
spin_lock(&oldf->file_lock);
old_fdt = files_fdtable(oldf);
- open_files = count_open_files(old_fdt);
+ open_files = sane_fdtable_size(old_fdt, max_fds);
}
copy_fd_bitmaps(new_fdt, old_fdt, open_files);
@@ -625,12 +637,9 @@ void fd_install(unsigned int fd, struct file *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)
+static struct file *pick_file(struct files_struct *files, unsigned fd)
{
- struct file *file;
+ struct file *file = NULL;
struct fdtable *fdt;
spin_lock(&files->file_lock);
@@ -642,15 +651,105 @@ int __close_fd(struct files_struct *files, unsigned fd)
goto out_unlock;
rcu_assign_pointer(fdt->fd[fd], NULL);
__put_unused_fd(files, fd);
- spin_unlock(&files->file_lock);
- return filp_close(file, files);
out_unlock:
spin_unlock(&files->file_lock);
- return -EBADF;
+ return file;
+}
+
+/*
+ * The same warnings as for __alloc_fd()/__fd_install() apply here...
+ */
+int __close_fd(struct files_struct *files, unsigned fd)
+{
+ struct file *file;
+
+ file = pick_file(files, fd);
+ if (!file)
+ return -EBADF;
+
+ return filp_close(file, files);
}
EXPORT_SYMBOL(__close_fd); /* for ksys_close() */
+/**
+ * __close_range() - Close all file descriptors in a given range.
+ *
+ * @fd: starting file descriptor to close
+ * @max_fd: last file descriptor to close
+ *
+ * This closes a range of file descriptors. All file descriptors
+ * from @fd up to and including @max_fd are closed.
+ */
+int __close_range(unsigned fd, unsigned max_fd, unsigned int flags)
+{
+ unsigned int cur_max;
+ struct task_struct *me = current;
+ struct files_struct *cur_fds = me->files, *fds = NULL;
+
+ if (flags & ~CLOSE_RANGE_UNSHARE)
+ return -EINVAL;
+
+ if (fd > max_fd)
+ return -EINVAL;
+
+ rcu_read_lock();
+ cur_max = files_fdtable(cur_fds)->max_fds;
+ rcu_read_unlock();
+
+ /* cap to last valid index into fdtable */
+ cur_max--;
+
+ if (flags & CLOSE_RANGE_UNSHARE) {
+ int ret;
+ unsigned int max_unshare_fds = NR_OPEN_MAX;
+
+ /*
+ * If the requested range is greater than the current maximum,
+ * we're closing everything so only copy all file descriptors
+ * beneath the lowest file descriptor.
+ */
+ if (max_fd >= cur_max)
+ max_unshare_fds = fd;
+
+ ret = unshare_fd(CLONE_FILES, max_unshare_fds, &fds);
+ if (ret)
+ return ret;
+
+ /*
+ * We used to share our file descriptor table, and have now
+ * created a private one, make sure we're using it below.
+ */
+ if (fds)
+ swap(cur_fds, fds);
+ }
+
+ max_fd = min(max_fd, cur_max);
+ while (fd <= max_fd) {
+ struct file *file;
+
+ file = pick_file(cur_fds, fd++);
+ if (!file)
+ continue;
+
+ filp_close(file, cur_fds);
+ cond_resched();
+ }
+
+ if (fds) {
+ /*
+ * We're done closing the files we were supposed to. Time to install
+ * the new file descriptor table and drop the old one.
+ */
+ task_lock(me);
+ me->files = cur_fds;
+ task_unlock(me);
+ put_files_struct(fds);
+ }
+
+ return 0;
+}
+
/*
* variant of __close_fd that gets a ref on the file for later fput.
* The caller must ensure that filp_close() called on the file, and then