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Bug #4180 is_link returns false when target doesnt exist (should return true)
Submitted: 2000-04-18 13:26 UTC Modified: 2002-10-01 15:03 UTC
From: dfarmer at evoke dot com Assigned:
Status: Closed Package: *General Issues
PHP Version: 3.0.14 OS: Linux 2.2.12-29.4smp #1 SMP Tue
Private report: No CVE-ID: None
 [2000-04-18 13:26 UTC] dfarmer at evoke dot com

It appears that is_link is incorrect when testing a symbolic link file whose target does not exist.


returns false when the link points to a non-existant target.  I believe it should return true based on the following C code:

#include <sys/stat.h>
#include <unistd.h>
#include <stdio.h>

main(int argc, char **argv)
    struct stat buf;
    char * file_name = argv[1];
    lstat(file_name, &buf);
    if (S_ISLNK(buf.st_mode))
        printf("file is a link\n");
        printf("file is not a link\n");

This prints "file is a link" even when the target doesn't exist.   

This is an issue because you can't tell when the symlink already exists even if it is incorrect.  I've tried lstat (returns 0 length array), fileexists (false), etc.   symlink fails on the creation of the link because it is there.  It seems like the only way to detect this condition is to have a successful readlink call combined with a false file_exists or symlink call.   

The ChangeLog for 3.0.15 and 3.0.16 doesn't address this issue as being fixed.


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 [2000-10-11 11:40 UTC]
Olivier Cahange <> reports this bug as being fixed in 4.0.3RC1
 [2000-10-11 12:58 UTC]
Minor typo in bug report number / forgot to engage brain :)
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