BUG FIX for getwd()

[Vadim Antonov avg@postman.ncube.com]

----FORWARDED MESSAGE----
From: markw@kira (Mark Wiley)
Subject: This is too much fun to keep to myself ...

If you call getwd with a buffer which it too small to contain
the current working directory, it returns 0 and places the message
'buffer too small' in the buffer EVEN if the buffer is too small
to contain that message.

Sigh.

Markw
-------------------------

The fix is appended, although the right way
to do things would be to change the way the
error message is returned (it should be in errstr...)

--vadim

File /sys/src/libc/9sys/getwd.c:

naiad% diff getwd.c.old getwd.c
14c14
< getwd(char *s , int size)
---
> getwd(char *s , int size0)
18a19
>       int size;
19a21
>       size = size0;
22c24
<               strcpy(s, "stat of / failed");
---
>               strncpy(s, "stat of / failed", size0);
29c31
<                       strcpy(s, "stat of . failed");
---
>                       strncpy(s, "stat of . failed", size0);
51c53
<                       strcpy(s, "chdir .. failed");
---
>                       strncpy(s, "chdir .. failed", size0);
65c67
<                       strcpy(s, "buffer too small");
---
>                       strncpy(s, "buffer too small", size0);
77c79
<               strcpy(s, "failed to return to .");
---
>               strncpy(s, "failed to return to .", size0);