Date: Mon, 27 Jul 2009 09:25:19 -0800 From: Mel Flynn <mel.flynn+fbsd.questions@mailing.thruhere.net> To: freebsd-questions@freebsd.org Subject: Re: How to find what symlink points to? Message-ID: <200907270925.19456.mel.flynn%2Bfbsd.questions@mailing.thruhere.net> In-Reply-To: <771031.86846.qm@web57007.mail.re3.yahoo.com> References: <771031.86846.qm@web57007.mail.re3.yahoo.com>
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On Monday 27 July 2009 05:45:13 Unga wrote:
> > > Hi all
> > >
> > > I need to remove some unwanted symlinks on /dev using
> >
> > a C program.
> >
> > > The "struct dirent" only shows the symlink name, how
> >
> > do I find what that
> >
> > > symlink points to for verification purpose?
> >
> > By using the readlink(2) system call.
>
> But readlink(2) fails with errno set to 2. Can readlink(2) use with dev
> nodes?
Works for me. errno 2 is ENOENT ("No such file or directory"). I would inspect
if your request path points to the right location.
% ./rl /dev/stderr
/dev/stderr => fd/2
% cat rl.c
#include <sys/types.h>
#include <sys/param.h>
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <err.h>
int main(int argc, char **argv)
{
char path[MAXPATHLEN], buf[MAXPATHLEN+1];
ssize_t res;
if( argc != 2 )
exit(67);
(void)strlcpy(path, argv[1], sizeof(path));
res = readlink(path, buf, sizeof(buf));
if( res < 0 )
err(EXIT_FAILURE, "readlink()");
buf[MAXPATHLEN] = '\0';
printf("%s => %s\n", path, buf);
return (0);
}
--
Mel
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