readlink null termination problem

Christopher Faylor cgf-no-personal-reply-please@cygwin.com
Tue Jan 6 01:30:00 GMT 2004


On Tue, Jan 06, 2004 at 08:17:14AM +0800, peter garrone wrote:
>I was having a problem with mkcramfs on cygwin creating symbolic links 
>for the compressed linux filesystem.
>
>mkcramfs uses malloc to allocate a buffer that it sends to the readlink function in cygwin path.cc
>That function uses memcpy to do a copy of the link into a buffer.
>Neither mkcramfs or readlink is null-terminating the string representing the link.
>
>Probably both are at fault. I have fixed my problem by zeroing the buffer in mkcramfs
> before calling readlink, but it would probably be beneficial if readlink terminates
> the returned string, if there is room.

NAME
       readlink - read value of a symbolic link

SYNOPSIS
       #include <unistd.h>

       int readlink(const char *path, char *buf, size_t bufsiz);

DESCRIPTION
       readlink  places  the  contents of the symbolic link path in the buffer
       buf, which has size bufsiz.  readlink does not append a  NUL  character
       to  buf.   It will truncate the contents (to a length of bufsiz charac-
       ters), in case the buffer is too small to hold all of the contents.

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