lkml.org 
[lkml]   [2012]   [Feb]   [20]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    Date
    From
    Subject[tip:core/types] Wrap accesses to the fd_sets in struct fdtable
    Commit-ID:  1dce27c5aa6770e9d195f2bb7db1db3d4dde5591
    Gitweb: http://git.kernel.org/tip/1dce27c5aa6770e9d195f2bb7db1db3d4dde5591
    Author: David Howells <dhowells@redhat.com>
    AuthorDate: Thu, 16 Feb 2012 17:49:42 +0000
    Committer: H. Peter Anvin <hpa@zytor.com>
    CommitDate: Sun, 19 Feb 2012 10:30:52 -0800

    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>
    ---
    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 ac2facc..46dfc6b 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 03c5fce..c2c5b07 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 7491801..35dd9c3 100644
    --- a/drivers/staging/android/binder.c
    +++ b/drivers/staging/android/binder.c
    @@ -408,11 +408,11 @@ repeat:
    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 76741d8..3dfd615 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 92ce83a..22cc38d 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 22764c7..75e7c1f 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 4c6992d..114fea0 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 @@ repeat:
    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 @@ 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 d4548dd..db6ab4b 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 82163c4..7675da2 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
    */

    \
     
     \ /
      Last update: 2012-02-20 22:17    [W:0.057 / U:58.936 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site