X-Git-Url: http://ftp.safe.ca/?a=blobdiff_plain;f=fs%2Ffile.c;h=34bb7f71d99404e8b91a4bfb0654505d1e537318;hb=f534116308a0d553641725c4619814337758784f;hp=7b3887e054d0bcb5e0e187c8e1e42691c4fadcd0;hpb=eceea0b3df05ed262ae32e0c6340cc7a3626632d;p=safe%2Fjmp%2Flinux-2.6

diff --git a/fs/file.c b/fs/file.c
index 7b3887e..34bb7f7 100644
--- a/fs/file.c
+++ b/fs/file.c
@@ -6,9 +6,11 @@
  *  Manage the dynamic fd arrays in the process files_struct.
  */
 
+#include <linux/module.h>
 #include <linux/fs.h>
 #include <linux/mm.h>
 #include <linux/time.h>
+#include <linux/sched.h>
 #include <linux/slab.h>
 #include <linux/vmalloc.h>
 #include <linux/file.h>
@@ -250,9 +252,18 @@ int expand_files(struct files_struct *files, int nr)
 	struct fdtable *fdt;
 
 	fdt = files_fdtable(files);
+
+	/*
+	 * N.B. For clone tasks sharing a files structure, this test
+	 * will limit the total number of files that can be opened.
+	 */
+	if (nr >= rlimit(RLIMIT_NOFILE))
+		return -EMFILE;
+
 	/* Do we need to expand? */
 	if (nr < fdt->max_fds)
 		return 0;
+
 	/* Can we expand? */
 	if (nr >= sysctl_nr_open)
 		return -EMFILE;
@@ -423,3 +434,63 @@ struct files_struct init_files = {
 	},
 	.file_lock	= __SPIN_LOCK_UNLOCKED(init_task.file_lock),
 };
+
+/*
+ * allocate a file descriptor, mark it busy.
+ */
+int alloc_fd(unsigned start, unsigned flags)
+{
+	struct files_struct *files = current->files;
+	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->fds_bits,
+					   fdt->max_fds, fd);
+
+	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;
+
+	FD_SET(fd, fdt->open_fds);
+	if (flags & O_CLOEXEC)
+		FD_SET(fd, fdt->close_on_exec);
+	else
+		FD_CLR(fd, fdt->close_on_exec);
+	error = fd;
+#if 1
+	/* Sanity check */
+	if (rcu_dereference_raw(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;
+}
+
+int get_unused_fd(void)
+{
+	return alloc_fd(0, 0);
+}
+EXPORT_SYMBOL(get_unused_fd);