On 2/14/22 13:59, Basile Starynkevitch wrote:
Hello,
Mir Immad asked:
Should the analyzer warn for code like this "when open fails" (like strchr
does when 'strchr' returns NULL)
int fd = open("NOFILE", O_RDONLY);
write(fd, "a", 1);
because of the bad file descriptor.
unless it is written like this:
if (!errno)
write(fd, "a", 1);
My opinion is yes, in most cases. BTW, the write should fail for a
read-only file descriptor.
A case (on Linux) where a check is probably not needed: isint
fd=open("/proc/self/exe", O_RDONLY); or int fd=open ("/dev/random",
O_RDONLY); done *near the beginning* of main. There are only
pathological cases where they won't succeed. I suspect that except for
very critical executable, testing such failures is practically useless.
And your analyzer might start from https://github.com/bstarynk/bismon/
or use https://frama-c.com/ <https://frama-c.com/>
PS. My pet project is http://refpersys.org/ (Soon generating code
compiled by GCC). It is not GCC related.
Be of course aware of Rice's theorem
<https://en.wikipedia.org/wiki/Rice%27s_theorem> 😁 so don't expect
writing the ultimate, perfect, static source code (or Gimple code) analyzer.
Cheers
--
Basile Starynkevitch<bas...@starynkevitch.net>
(only mine opinions / les opinions sont miennes uniquement)
92340 Bourg-la-Reine, France
web page: starynkevitch.net/Basile/
