From 1dce27c5aa6770e9d195f2bb7db1db3d4dde5591 Mon Sep 17 00:00:00 2001 From: David Howells Date: Thu, 16 Feb 2012 17:49:42 +0000 Subject: [PATCH] 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 --- Documentation/filesystems/files.txt | 4 +-- arch/powerpc/platforms/cell/spufs/coredump.c | 2 +- drivers/staging/android/binder.c | 10 +++---- fs/autofs4/dev-ioctl.c | 2 +- fs/exec.c | 4 +-- fs/fcntl.c | 18 ++++++------ fs/file.c | 8 +++--- fs/open.c | 4 +-- fs/proc/base.c | 2 +- include/linux/fdtable.h | 30 ++++++++++++++++++++ 10 files changed, 57 insertions(+), 27 deletions(-) diff --git a/Documentation/filesystems/files.txt b/Documentation/filesystems/files.txt index ac2facc50d2a..46dfc6b038c3 100644 --- a/Documentation/filesystems/files.txt +++ b/Documentation/filesystems/files.txt @@ -113,8 +113,8 @@ the fdtable structure - if (fd >= 0) { /* locate_fd() may have expanded fdtable, load the ptr */ fdt = files_fdtable(files); - FD_SET(fd, fdt->open_fds); - FD_CLR(fd, fdt->close_on_exec); + __set_open_fd(fd, fdt); + __clear_close_on_exec(fd, fdt); spin_unlock(&files->file_lock); ..... diff --git a/arch/powerpc/platforms/cell/spufs/coredump.c b/arch/powerpc/platforms/cell/spufs/coredump.c index 03c5fce2a5b3..c2c5b078ba80 100644 --- a/arch/powerpc/platforms/cell/spufs/coredump.c +++ b/arch/powerpc/platforms/cell/spufs/coredump.c @@ -122,7 +122,7 @@ static struct spu_context *coredump_next_context(int *fd) struct spu_context *ctx = NULL; for (; *fd < fdt->max_fds; (*fd)++) { - if (!FD_ISSET(*fd, fdt->open_fds)) + if (!fd_is_open(*fd, fdt)) continue; file = fcheck(*fd); diff --git a/drivers/staging/android/binder.c b/drivers/staging/android/binder.c index 7491801a661c..35dd9c370e55 100644 --- a/drivers/staging/android/binder.c +++ b/drivers/staging/android/binder.c @@ -408,11 +408,11 @@ int task_get_unused_fd_flags(struct binder_proc *proc, int flags) goto repeat; } - 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); files->next_fd = fd + 1; #if 1 /* Sanity check */ @@ -453,7 +453,7 @@ static void task_fd_install( 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; } @@ -479,7 +479,7 @@ static long task_close_fd(struct binder_proc *proc, unsigned int fd) 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/autofs4/dev-ioctl.c b/fs/autofs4/dev-ioctl.c index 76741d8d7786..3dfd615afb6b 100644 --- a/fs/autofs4/dev-ioctl.c +++ b/fs/autofs4/dev-ioctl.c @@ -230,7 +230,7 @@ static void autofs_dev_ioctl_fd_install(unsigned int fd, struct file *file) 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 92ce83a11e90..22cc38d9e79f 100644 --- a/fs/exec.c +++ b/fs/exec.c @@ -2078,8 +2078,8 @@ static int umh_pipe_setup(struct subprocess_info *info, struct cred *new) 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 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) diff --git a/fs/file.c b/fs/file.c index 4c6992d8f3ba..114fea0a2cec 100644 --- a/fs/file.c +++ b/fs/file.c @@ -366,7 +366,7 @@ struct files_struct *dup_fd(struct files_struct *oldf, int *errorp) * 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 @@ int alloc_fd(unsigned start, unsigned flags) 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 77becc041149..5720854156db 100644 --- a/fs/open.c +++ b/fs/open.c @@ -836,7 +836,7 @@ EXPORT_SYMBOL(dentry_open); 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 @@ SYSCALL_DEFINE1(close, unsigned int, fd) 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 d4548dd49b02..db6ab4b36a0b 100644 --- a/fs/proc/base.c +++ b/fs/proc/base.c @@ -1754,7 +1754,7 @@ static int proc_fd_info(struct inode *inode, struct path *path, char *info) 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) { diff --git a/include/linux/fdtable.h b/include/linux/fdtable.h index 82163c4b32c9..7675da2c18f7 100644 --- a/include/linux/fdtable.h +++ b/include/linux/fdtable.h @@ -38,6 +38,36 @@ struct fdtable { struct fdtable *next; }; +static inline void __set_close_on_exec(int fd, struct fdtable *fdt) +{ + FD_SET(fd, fdt->close_on_exec); +} + +static inline void __clear_close_on_exec(int fd, struct fdtable *fdt) +{ + FD_CLR(fd, fdt->close_on_exec); +} + +static inline bool close_on_exec(int fd, const struct fdtable *fdt) +{ + return FD_ISSET(fd, fdt->close_on_exec); +} + +static inline void __set_open_fd(int fd, struct fdtable *fdt) +{ + FD_SET(fd, fdt->open_fds); +} + +static inline void __clear_open_fd(int fd, struct fdtable *fdt) +{ + FD_CLR(fd, fdt->open_fds); +} + +static inline bool fd_is_open(int fd, const struct fdtable *fdt) +{ + return FD_ISSET(fd, fdt->open_fds); +} + /* * Open file table structure */ -- GitLab