kumar@gtenmc.UUCP (S.Kumar) (09/15/90)
A Unix question
Is there a way to get the filename in UNIX given the file descriptor.
(in a given process)
I think the crash program provides a list of inodes for the filenames
which the process has opened.
Is there any call in unix which would do the job (and if not why not)?
I don't mind an external suid program which takes the pid and fd
and gets the filename.
Is it possible at all to do that ?
(This would be very useful to me to find out the filename which
tmpfile() has created which I could then pass to other programs)
Fri Sep 14 15:53:41 PDT 1990
Thanks in advance ,
S. Kumarbrnstnd@kramden.acf.nyu.edu (Dan Bernstein) (09/15/90)
In article <870@gtenmc.UUCP> kumar@gtenmc.UUCP (S.Kumar) writes: > A Unix question > Is there a way to get the filename in UNIX given the file descriptor. > (in a given process) Not reliably. A file descriptor may be associated with several different filenames, or none at all. The filenames may be hidden inside directories that you can't read. They may change at any time. > I think the crash program provides a list of inodes for the filenames > which the process has opened. Filenames can change; how do you know it's the same file as when the process was running? A root process can search the filesystem and (unreliably, unless the disks are unmounted) find a file with a given inode, but that's slow and really suitable only for administrative duties. ---Dan
allbery@NCoast.ORG (Brandon S. Allbery KB8JRR/KT) (09/18/90)
As quoted from <870@gtenmc.UUCP> by kumar@gtenmc.UUCP (S.Kumar): +--------------- | (This would be very useful to me to find out the filename which | tmpfile() has created which I could then pass to other programs) +--------------- Someone else answered your question; I'll address this. You're doing this wrong.... (1) tmpfile() creates a named file, then unlinks it. By the time you get control back from tmpfile(), the file it creates doesn't *have* a name. (2) In any case, what you want is bass-ackwards. You have to do major work to get the filename from a file descriptor (that is, if it *has* one; pipes, un-"bind"-ed (AF_UNIX) sockets, etc. need not apply). It's much easier to do it in the proper order: char tf_name[L_tmpnam]; FILE *tf_fp; tmpnam(tf_name); tf_fp = fopen(tf_name, "w"); Much easier, no? ++Brandon -- Me: Brandon S. Allbery VHF/UHF: KB8JRR/KT on 220, 2m, 440 Internet: allbery@NCoast.ORG Packet: KB8JRR @ WA8BXN America OnLine: KB8JRR AMPR: KB8JRR.AmPR.ORG [44.70.4.88] uunet!usenet.ins.cwru.edu!ncoast!allbery Delphi: ALLBERY