On Sat, 2008-02-09 at 20:01 +0800, Eugene Teo wrote:
> This patch extends /proc/<pid>/fdinfo/<fd> to report information about open
> files, and pathname. This information can be useful to know when debugging an
> application.
>
> For each file descriptor, the information is provided in the following format:
>
> kerndev: ~/code/kernel# cat /proc/`pgrep pickup`/fdinfo/6
> mode: 0622
> dev: 253,0
> ino: 21463057
These are already available via 'stat /proc/<pid>/fd/<fd>'
> uid: 89
> gid: 89
AFAICS file->f_[ug]id are only used by the netfilter code, but I guess
it wouldn't hurt to show them here. But please add fields at the end of
the file, instead of the beggining.
> rdev: 0,0
This is in struct stat too.
> pos: 0
> flags: 04002 FD_CLOEXEC # if close-on-exec flag is set
FD_CLOEXEC should be on a separate line, because it's not an O_FOO flag.
> path: /var/spool/postfix/public/pickup
readlink /proc/<pid>/fd/<fd>
Thanks,
Miklos
>
> You can also use this to find out more information about locked open files:
>
> kerndev: /proc# cat /proc/locks
> 1: POSIX ADVISORY WRITE 2663 fd:00:21398205 0 EOF
> ^^^^ ^^^^^^^^
> 2: FLOCK ADVISORY WRITE 2654 fd:00:21398203 0 EOF
> 3: FLOCK ADVISORY WRITE 2564 fd:00:21463056 0 EOF
> 4: FLOCK ADVISORY WRITE 2266 fd:00:21398151 0 EOF
> kerndev: /proc# cd 2663/fdinfo/
> kerndev: /proc/2663/fdinfo# grep 21398205 * -B2 -A6
> ^^^^
> 3-mode: 0644
> 3-dev: 253,0
> 3:ino: 21398205
> ^^^^^^^^
> 3-uid: 0
> 3-gid: 0
> 3-rdev: 0,0
> 3-pos: 5
> 3-flags: 02 FD_CLOEXEC
> 3-path: /var/run/atd.pid
>
> Signed-off-by: Eugene Teo <[EMAIL PROTECTED]>
> ---
> fs/proc/base.c | 47 +++++++++++++++++++++++++++++++++++++++++------
> 1 files changed, 41 insertions(+), 6 deletions(-)
>
> diff --git a/fs/proc/base.c b/fs/proc/base.c
> index c59852b..dde617f 100644
> --- a/fs/proc/base.c
> +++ b/fs/proc/base.c
> @@ -1402,7 +1402,7 @@ out:
> return ~0U;
> }
>
> -#define PROC_FDINFO_MAX 64
> +#define PROC_FDINFO_MAX 256
>
> static int proc_fd_info(struct inode *inode, struct dentry **dentry,
> struct vfsmount **mnt, char *info)
> @@ -1411,6 +1411,7 @@ static int proc_fd_info(struct inode *inode, struct
> dentry **dentry,
> struct files_struct *files = NULL;
> struct file *file;
> int fd = proc_fd(inode);
> + int ret = -ENOENT;
>
> if (task) {
> files = get_files_struct(task);
> @@ -1424,24 +1425,58 @@ static int proc_fd_info(struct inode *inode, struct
> dentry **dentry,
> spin_lock(&files->file_lock);
> file = fcheck_files(files, fd);
> if (file) {
> + ret = 0;
> +
> if (mnt)
> *mnt = mntget(file->f_path.mnt);
> if (dentry)
> *dentry = dget(file->f_path.dentry);
> - if (info)
> + /* called by proc_fdinfo_read() */
> + if (info) {
> + struct fdtable *fdt = files_fdtable(files);
> + struct dentry *d = dget(file->f_path.dentry);
> + struct vfsmount *v = mntget(file->f_path.mnt);
> + char *page = (char
> *)__get_free_page(GFP_TEMPORARY);
> + int gcoe = FD_ISSET(fd, fdt->close_on_exec);
> + int dev_nr = d->d_inode->i_sb->s_dev;
> + int rdev_nr = d->d_inode->i_rdev;
> +
> + if (!page) {
> + ret = -ENOMEM;
> + goto out;
> + }
> +
> snprintf(info, PROC_FDINFO_MAX,
> + "mode:\t0%o\n"
> + "dev:\t%d,%d\n"
> + "ino:\t%ld\n"
> + "uid:\t%d\n"
> + "gid:\t%d\n"
> + "rdev:\t%d,%d\n"
> "pos:\t%lli\n"
> - "flags:\t0%o\n",
> + "flags:\t0%o %s\n"
> + "path:\t%s\n",
> + d->d_inode->i_mode & 0777,
> + MAJOR(dev_nr), MINOR(dev_nr),
> + d->d_inode->i_ino,
> + file->f_uid, file->f_gid,
> + MAJOR(rdev_nr), MINOR(rdev_nr),
> (long long) file->f_pos,
> - file->f_flags);
> + file->f_flags, gcoe ? "FD_CLOEXEC" :
> "",
> + d_path(d, v, page, PAGE_SIZE));
> + free_page((unsigned long)page);
> +out:
> + mntput(v);
> + dput(d);
> + }
> spin_unlock(&files->file_lock);
> put_files_struct(files);
> - return 0;
> + return ret;
> }
> spin_unlock(&files->file_lock);
> put_files_struct(files);
> }
> - return -ENOENT;
> + return ret;
> }
>
> static int proc_fd_link(struct inode *inode, struct dentry **dentry,
>
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