Study: Few bugs in MySQL database

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lint and char[256]

you know the old function calls

char *inputstring=(char *)malloc(2048);
scanf(INPUTSTREAM,"%s",inputstring);

how many times have you used the same kind of
code as the above. Note by default, you can
overrun program memory by there being a string on
INPUTSTREAM larger than 2048. If you hit the
stack, you can put a return address in there, put
code in the overflow, and next time a subroutine
finishes, you've got control.

When you write quick n dirty code, you do the
above. Later it gets missed. This is why memory
control isn't any good in the hands of most
programmers.

Memory leaks can be tested for by lint and so on,
but if you have a process running for a while,
how do you distinguish from heap that's being
allocated and heap that's been "lost".

I think there is some GNU stdlib which tracks
lost malloc'd memory and when a pointer which is
the last reference to a block is assigned to a
new value, the pointer assignment barfs. I think
the pointers probably have reference counters
built in, and are smart in some way.

Still, write it in java, and you know you havent
got the same problem! (note you can compile java
with gcj, which is just another face of gnuC).

Posted by: hipparchus2001   Posted on: 02/04/05 You are currently: a Guest | Members login | Terms of Use

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