DragonFly kernel List (threaded) for 2004-06
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Re: Show entire path for checkpointing
:When a program is being checkpointed the checkpoint file is stored in the cwd
:for the program in question, which might be anything. So I have a patch here
:that instead of just showing the filename of the new checkpoint file, it also
:shows the path where it is stored.
:
:http://eirikn.kerneled.org/dragonfly/ckpt-show-entire-path.patch
:
:This patch depends on another patch I have here which separate the __getcwd
:function into a syscall part and a kernel part.
:
:http://eirikn.kerneled.org/dragonfly/split-getcwd-syscall.patch
:
:Any feedback would be great.
:
:--
:Eirik Nygaard
:eirikn@xxxxxxxxxxxx Never let a computer know you're in a hurry.
--- on the check point changes ---
There is an overflow in temp when you added the '/'. You are replacing
the terminating \0 with '/' and not adding a new terminating \0, plus
you may exceed the buffer size. so instead of:
if (ckptfilename[0] != '/') {
if (kern_getcwd(temp, MAXPATHLEN) != 0) { <<< SIZE OVERFLOW
free(temp, M_TEMP); (due to append
return NULL; below).
}
temp[strlen(temp)] = '/'; <<<< BAD
n = strlen(temp); <<<< BAD
}
do this:
if (ckptfilename[0] != '/') {
if (kern_getcwd(temp, MAXPATHLEN - 1) != 0) {
free(temp, M_TEMP);
return NULL;
}
n = strlen(temp);
temp[n++] = '/';
temp[n] = 0;
}
--- on the getcwd() changes ---
#1: since the error path is so short, don't use a 'goto' in your
__getcwd(). Just conditionalize the copyout.
if (error == 0)
error = copyout(...)
#2: Use bcopy() rather then strncpy() to copy-down the path at the end.
strncpy() is not guarenteed to handle overlapping data.
Otherwise it looks good and, with those changes, can be committed.
-Matt
Matthew Dillon
<dillon@xxxxxxxxxxxxx>
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