Template Version: @(#)sac_nextcase 1.68 02/23/09 SMI
This information is Copyright 2009 Sun Microsystems
1. Introduction
1.1. Project/Component Working Name:
pfiles offset
1.2. Name of Document Author/Supplier:
Author: Daniel Mick
1.3 Date of This Document:
13 November, 2009
4. Technical Description
PROBLEM:
pfiles(1) prints various information about open files in a process
(the manpage describes it as fstat(2) and fcntl(2) information, as well
as network endpoints, socket options, and the file path, if available).
Occasionally it would be useful to see the file offset for files that
support seek; for example, for long-running processes that process large
files sequentially, it can be useful to discover the current position
in the file to estimate time to completion. The information is readily
available, and easy to output.
pfiles(1) output is currently classified as Uncommitted.
PROPOSAL:
Add a new "offset:" output field to pfiles (in verbose mode, that is,
lacking the -n switch). The field would be printed for any file that
responds to lseek() with a valid offset, appearing just after the
pathname (if any). Several output formats were proposed and discussed;
locating just after all the other field:value items would be consistent,
but would almost certainly cause linewrap, and it seems a shame to
waste an entire line on one new field. Also, there's some value in
having the offset near the pathname, as that's likely the reference
field of interest for the offset.
As an example: here is output from a login ksh process before the change:
5968: ksh
Current rlimit: 256 file descriptors
0: S_IFCHR mode:0620 dev:387,0 ino:1560118988 uid:23805 gid:7 rdev:24,3
O_RDWR|O_LARGEFILE
/dev/pts/3
1: S_IFCHR mode:0620 dev:387,0 ino:1560118988 uid:23805 gid:7 rdev:24,3
O_RDWR|O_LARGEFILE
/dev/pts/3
2: S_IFCHR mode:0620 dev:387,0 ino:1560118988 uid:23805 gid:7 rdev:24,3
O_RDWR|O_LARGEFILE
/dev/pts/3
3: S_IFCHR mode:0620 dev:387,0 ino:1560118988 uid:23805 gid:7 rdev:24,3
O_RDWR|O_LARGEFILE
/dev/pts/3
10: S_IFCHR mode:0620 dev:387,0 ino:1560118988 uid:23805 gid:7 rdev:24,3
O_RDWR|O_LARGEFILE FD_CLOEXEC
/dev/pts/3
63: S_IFREG mode:0600 dev:400,1 ino:254311 uid:23805 gid:10 size:23938
O_RDWR|O_APPEND|O_CREAT|O_LARGEFILE FD_CLOEXEC
/home/dmick/.sh_history
and here is the proposed pfiles output:
5968: ksh
Current rlimit: 256 file descriptors
0: S_IFCHR mode:0620 dev:387,0 ino:1560118988 uid:23805 gid:7 rdev:24,3
O_RDWR|O_LARGEFILE
/dev/pts/3 offset:32577
1: S_IFCHR mode:0620 dev:387,0 ino:1560118988 uid:23805 gid:7 rdev:24,3
O_RDWR|O_LARGEFILE
/dev/pts/3 offset:32577
2: S_IFCHR mode:0620 dev:387,0 ino:1560118988 uid:23805 gid:7 rdev:24,3
O_RDWR|O_LARGEFILE
/dev/pts/3 offset:32577
3: S_IFCHR mode:0620 dev:387,0 ino:1560118988 uid:23805 gid:7 rdev:24,3
O_RDWR|O_LARGEFILE
/dev/pts/3 offset:32577
10: S_IFCHR mode:0620 dev:387,0 ino:1560118988 uid:23805 gid:7 rdev:24,3
O_RDWR|O_LARGEFILE FD_CLOEXEC
/dev/pts/3 offset:32577
63: S_IFREG mode:0600 dev:400,1 ino:254311 uid:23805 gid:10 size:24000
O_RDWR|O_APPEND|O_CREAT|O_LARGEFILE FD_CLOEXEC
/home/dmick/.sh_history offset:24000
