Wrap accesses to the fd_sets in struct fdtable
Wrap accesses to the fd_sets in struct fdtable (for recording open files and
close-on-exec flags) so that we can move away from using fd_sets since we
abuse the fd_set structs by not allocating the full-sized structure under
normal circumstances and by non-core code looking at the internals of the
fd_sets.
The first abuse means that use of FD_ZERO() on these fd_sets is not permitted,
since that cannot be told about their abnormal lengths.
This introduces six wrapper functions for setting, clearing and testing
close-on-exec flags and fd-is-open flags:
void __set_close_on_exec(int fd, struct fdtable *fdt);
void __clear_close_on_exec(int fd, struct fdtable *fdt);
bool close_on_exec(int fd, const struct fdtable *fdt);
void __set_open_fd(int fd, struct fdtable *fdt);
void __clear_open_fd(int fd, struct fdtable *fdt);
bool fd_is_open(int fd, const struct fdtable *fdt);
Note that I've prepended '__' to the names of the set/clear functions because
they require the caller to hold a lock to use them.
Note also that I haven't added wrappers for looking behind the scenes at the
the array. Possibly that should exist too.
Signed-off-by: David Howells <dhowells@redhat.com>
Link: http://lkml.kernel.org/r/20120216174942.23314.1364.stgit@warthog.procyon.org.uk
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/fs/autofs4/dev-ioctl.c b/fs/autofs4/dev-ioctl.c
index 76741d8..3dfd615a 100644
--- a/fs/autofs4/dev-ioctl.c
+++ b/fs/autofs4/dev-ioctl.c
@@ -230,7 +230,7 @@
fdt = files_fdtable(files);
BUG_ON(fdt->fd[fd] != NULL);
rcu_assign_pointer(fdt->fd[fd], file);
- FD_SET(fd, fdt->close_on_exec);
+ __set_close_on_exec(fd, fdt);
spin_unlock(&files->file_lock);
}
diff --git a/fs/exec.c b/fs/exec.c
index 92ce83a..22cc38d 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -2078,8 +2078,8 @@
fd_install(0, rp);
spin_lock(&cf->file_lock);
fdt = files_fdtable(cf);
- FD_SET(0, fdt->open_fds);
- FD_CLR(0, fdt->close_on_exec);
+ __set_open_fd(0, fdt);
+ __clear_close_on_exec(0, fdt);
spin_unlock(&cf->file_lock);
/* and disallow core files too */
diff --git a/fs/fcntl.c b/fs/fcntl.c
index 22764c7c..75e7c1f 100644
--- a/fs/fcntl.c
+++ b/fs/fcntl.c
@@ -32,20 +32,20 @@
spin_lock(&files->file_lock);
fdt = files_fdtable(files);
if (flag)
- FD_SET(fd, fdt->close_on_exec);
+ __set_close_on_exec(fd, fdt);
else
- FD_CLR(fd, fdt->close_on_exec);
+ __clear_close_on_exec(fd, fdt);
spin_unlock(&files->file_lock);
}
-static int get_close_on_exec(unsigned int fd)
+static bool get_close_on_exec(unsigned int fd)
{
struct files_struct *files = current->files;
struct fdtable *fdt;
- int res;
+ bool res;
rcu_read_lock();
fdt = files_fdtable(files);
- res = FD_ISSET(fd, fdt->close_on_exec);
+ res = close_on_exec(fd, fdt);
rcu_read_unlock();
return res;
}
@@ -90,15 +90,15 @@
err = -EBUSY;
fdt = files_fdtable(files);
tofree = fdt->fd[newfd];
- if (!tofree && FD_ISSET(newfd, fdt->open_fds))
+ if (!tofree && fd_is_open(newfd, fdt))
goto out_unlock;
get_file(file);
rcu_assign_pointer(fdt->fd[newfd], file);
- FD_SET(newfd, fdt->open_fds);
+ __set_open_fd(newfd, fdt);
if (flags & O_CLOEXEC)
- FD_SET(newfd, fdt->close_on_exec);
+ __set_close_on_exec(newfd, fdt);
else
- FD_CLR(newfd, fdt->close_on_exec);
+ __clear_close_on_exec(newfd, fdt);
spin_unlock(&files->file_lock);
if (tofree)
diff --git a/fs/file.c b/fs/file.c
index 4c6992d..114fea0 100644
--- a/fs/file.c
+++ b/fs/file.c
@@ -366,7 +366,7 @@
* is partway through open(). So make sure that this
* fd is available to the new process.
*/
- FD_CLR(open_files - i, new_fdt->open_fds);
+ __clear_open_fd(open_files - i, new_fdt);
}
rcu_assign_pointer(*new_fds++, f);
}
@@ -460,11 +460,11 @@
if (start <= files->next_fd)
files->next_fd = fd + 1;
- FD_SET(fd, fdt->open_fds);
+ __set_open_fd(fd, fdt);
if (flags & O_CLOEXEC)
- FD_SET(fd, fdt->close_on_exec);
+ __set_close_on_exec(fd, fdt);
else
- FD_CLR(fd, fdt->close_on_exec);
+ __clear_close_on_exec(fd, fdt);
error = fd;
#if 1
/* Sanity check */
diff --git a/fs/open.c b/fs/open.c
index 77becc0..5720854 100644
--- a/fs/open.c
+++ b/fs/open.c
@@ -836,7 +836,7 @@
static void __put_unused_fd(struct files_struct *files, unsigned int fd)
{
struct fdtable *fdt = files_fdtable(files);
- __FD_CLR(fd, fdt->open_fds);
+ __clear_open_fd(fd, fdt);
if (fd < files->next_fd)
files->next_fd = fd;
}
@@ -1080,7 +1080,7 @@
if (!filp)
goto out_unlock;
rcu_assign_pointer(fdt->fd[fd], NULL);
- FD_CLR(fd, fdt->close_on_exec);
+ __clear_close_on_exec(fd, fdt);
__put_unused_fd(files, fd);
spin_unlock(&files->file_lock);
retval = filp_close(filp, files);
diff --git a/fs/proc/base.c b/fs/proc/base.c
index d4548dd..db6ab4b 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -1754,7 +1754,7 @@
fdt = files_fdtable(files);
f_flags = file->f_flags & ~O_CLOEXEC;
- if (FD_ISSET(fd, fdt->close_on_exec))
+ if (close_on_exec(fd, fdt))
f_flags |= O_CLOEXEC;
if (path) {