From 1dce27c5aa6770e9d195f2bb7db1db3d4dde5591 Mon Sep 17 00:00:00 2001 From: David Howells Date: Thu, 16 Feb 2012 17:49:42 +0000 Subject: 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 Link: http://lkml.kernel.org/r/20120216174942.23314.1364.stgit@warthog.procyon.org.uk Signed-off-by: H. Peter Anvin Cc: Al Viro --- fs/fcntl.c | 18 +++++++++--------- 1 file changed, 9 insertions(+), 9 deletions(-) (limited to 'fs/fcntl.c') diff --git a/fs/fcntl.c b/fs/fcntl.c index 22764c7c8382..75e7c1f3a080 100644 --- a/fs/fcntl.c +++ b/fs/fcntl.c @@ -32,20 +32,20 @@ void set_close_on_exec(unsigned int fd, int flag) 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 @@ SYSCALL_DEFINE3(dup3, unsigned int, oldfd, unsigned int, newfd, int, flags) 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) -- cgit v1.2.3