Hi Ron,
I manned for the call and is not available in my linux box.
May be I can download that.Thanks for the response.
regards-
kaushal.
On Fri, 2005-04-15 at 07:15, Ron Michael Khu wrote:
> Hmm..
> Im not familiar with the implementation of lsof... but I do know that
> with pstat_getproc-related functions like pstat_getfile2(),
> it is possible to retrieve information on all the open files of a
> certain process(given it's PID). It is even possible to
> retrieve information about how many threads a particular process has
> created.
>
> BTW, the attached source code is from the HP/UX man page for
> pstat_getfile2(), I dont know if the pstat functions
> of hp/ux is the same or is supported in linux.
>
> And like Mr. Ozgur([EMAIL PROTECTED]), I dont know how to retrieve
> the filename given only a filedescriptor...
> because with pstat_getfile2() Im passing PID's.
>
> -Ron
>
>
> ,kaushal wrote:
>
> >Hi Steve,
> > Thanks for the response.But how will lsof work for a particular PID.If
> >lsof can print all the files by their names then why can't any c
> >program?The idea was to prove that the file /dev/pts/9 or some no. is
> >opened by the bash and to it are the stdin,stdout and stderr
> >associated.For that ,the fds 0,1,and 2 are supposed to point to the same
> >file /dev/pts/9 or say /dev/tty3 ....
> >This can be proved using lsof -p <PID OF THE BASH> .But how to prove
> >that from within a c program?This lead to the sol if we can get the
> >filename from the file descriptor and print it on the screen.
> >
> >regards-
> >kaushal.
> >On Thu, 2005-04-14 at 16:07, Steve Graegert wrote:
> >
> >
> >>On 4/14/05, kaushal <[EMAIL PROTECTED]> wrote:
> >>
> >>
> >>>Hello all,
> >>> How can I get the filename/pathname given the open file
> >>> descriptor?Does
> >>>fstat provide this feature internally?Can somebody give the code snippet
> >>>for this.
> >>>
> >>>
> >>There is no such thing. It is not possible to obtain a FD's filename
> >>reliably. Unless you are absolutely sure that this particular FD
> >>points to a file (or directory) and not to a socket, pipe or
> >>something similar, you will not be able to use fstat reliably. Which
> >>of stat's fields are suggesting to be helpful reagarding to your
> >>problem? st_ino? How would you locate a file based on its file ID?
> >>This would require scanning the complete file system (and probably
> >>more than one). Another problem is, that an FD might be associated
> >>with other files at the same time or files can be stored inside a
> >>directory that you can't read due to lack of sufficient permissions.
> >>What you are looking for is some kind of reverse lookup to unwind the
> >>many-to-one relationship of files and inodes.
> >>
> >>A couple of years ago Floyd Davidson suggested some code that may
> >>point you to the right direction (not tested):
> >>
> >>/* A demo program to locate file names related to an inode number */
> >>
> >>#include <stdio.h>
> >>#include <stdlib.h>
> >>#include <unistd.h>
> >>#include <string.h>
> >>#include <sys/stat.h>
> >>#include <dirent.h>
> >>#include <limits.h>
> >>
> >>void scan_list(char *curdir, struct dirent **ptr_nl, int dirs);
> >>int file_select(const struct dirent *nl);
> >>
> >>ino_t inode;
> >>char curdir[PATH_MAX] = "."; /* default search directory */
> >>
> >>int
> >>main(int argc, char **argv)
> >>{
> >> struct dirent **namelist;
> >> struct stat st;
> >>
> >> if (argc < 2 || argc > 3) {
> >> fprintf(stderr,"usage: %s inode [directory]\n", argv[0]);
> >> exit(EXIT_FAILURE);
> >> }
> >> inode = strtoul(argv[1], NULL, 10);
> >> if (!inode) {
> >> fprintf(stderr,"Error: invalid inode\n");
> >> exit(EXIT_FAILURE);
> >> }
> >> if (argc == 3 && !lstat(argv[2], &st) && S_ISDIR(st.st_mode)) {
> >> strcpy(curdir, argv[2]);
> >> }
> >>
> >> scan_list(curdir, namelist,
> >> scandir(curdir, &namelist, file_select, alphasort));
> >> return EXIT_SUCCESS;
> >>}
> >>
> >>/*
> >> * returns 1 for directories, otherwise 0
> >> * and displays any filename which matches inode.
> >> */
> >>int
> >>file_select(const struct dirent *nl)
> >>{
> >> struct stat st;
> >> char curfile[PATH_MAX];
> >>
> >> sprintf(curfile, "%s/%s", curdir, nl->d_name);
> >> if (0 == lstat(curfile, &st)) {
> >> /* report a matching inode number */
> >> if (st.st_ino == inode) {
> >> printf(" %6lu %-20s \n", (unsigned long) st.st_ino, curfile);
> >> }
> >> /* skip these directories */
> >> if (!strcmp(nl->d_name, ".") || !strcmp(nl->d_name, "..")) {
> >> return 0;
> >> }
> >> /* otherwise list all directories */
> >> if (S_ISDIR(st.st_mode)) {
> >> return 1;
> >> }
> >> } return 0;
> >>}
> >>
> >>/* descend through all directories */
> >>void
> >>scan_list(char *olddir, struct dirent **ptr_nl, int dirs)
> >>{
> >> char savedir[PATH_MAX];
> >> int i;
> >> struct dirent **namelist;
> >>
> >> if (dirs > 0) {
> >> for (i = 0; i < dirs; ++i) {
> >> strcpy(savedir, curdir);
> >> sprintf(curdir,"%s/%s", olddir, ptr_nl[i]->d_name);
> >> scan_list(curdir, namelist,
> >> scandir(curdir, &namelist, file_select, alphasort));
> >> strcpy(curdir, savedir);
> >> }
> >> }
> >>}
> >>
> >>/* End of demo program */
> >>
> >>Kind Regards
> >>
> >> \Steve
> >>
> >>--
> >>
> >>Steve Graegert <[EMAIL PROTECTED]>
> >>Independent Software Consultant {C/C++ && Java && .NET}
> >>Mobile: +49 (176) 21 24 88 69
> >>Office: +49 (9131) 71 26 40 9
> >>
> >>
> >
> >-
> >To unsubscribe from this list: send the line "unsubscribe
> >linux-c-programming" in
> >the body of a message to [EMAIL PROTECTED]
> >More majordomo info at http://vger.kernel.org/majordomo-info.html
> >
> >
> >
> >
>
>
> ______________________________________________________________________
> #include <sys/param.h>
> #include <sys/pstat.h>
> #include <sys/unistd.h>
> #include <stdio.h>
>
> int main( int argc, char *argv[] )
> {
> #define BURST ((size_t)10)
> struct pst_fileinfo2 psf[BURST];
> int i, count;
> int idx = 0; /* index within the context */
>
> if ( argc != 2 )
> {
> printf( "args: <pid>\n" );
> exit( 1 );
> }
> pid_t target = atoi( argv[1] );
>
> (void)printf("Open files for process PID %d\n", target);
>
> /* loop until all fetched */
> while ((count = pstat_getfile2(psf, sizeof(struct pst_fileinfo2),
> BURST, idx, target)) > 0) {
> /* process them (max of BURST) at a time */
> for (i = 0; i < count; i++) {
> (void)printf("fd #%d\tFSid %x:%x\tfileid %d\n",
> psf[i].psf_fd,
> psf[i].psf_id.psf_fsid.psfs_id,
> psf[i].psf_id.psf_fsid.psfs_type,
> psf[i].psf_id.psf_fileid);
> }
>
> /*
> * Now go back and do it again, using the
> * next index after the current 'burst'
> */
> idx = psf[count-1].psf_fd + 1;
> }
> if (count == -1)
> perror("pstat_getfile2()");
>
> #undef BURST
> }
>
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