Hello,
I cloned smatch (ca3d9889352dabbd3dcd403cce3e702a56c7d2b2), and tried to run
it on my illumos-based [1] laptop. There was one quick hack I had to do to
get it to run because `uname -m` is "i86pc" on both 32-bit and 64-bit x86.
(The machine is i86pc.) `uname -p` spits out "i386" on both 32-bit and 64-bit.
(The processor is i386 compatible.)
diff --git a/cgcc b/cgcc
index c075e5f..26d10f0 100755
--- a/cgcc
+++ b/cgcc
@@ -271,7 +271,7 @@ sub add_specs {
chomp $os;
return &add_specs (lc $os);
} elsif ($spec eq 'host_arch_specs') {
- my $arch = `uname -m`;
+ my $arch = `uname -p`;
chomp $arch;
if ($arch =~ /^(i.?86|athlon)$/i) {
return &add_specs ('i86');
Anyway, it builds and runs fine. At this point. It does however run into
something it doesn't know how to deal with. Specifically, if I include
unistd.h, I get:
/usr/include/unistd.h:565:26: error: attribute '__returns_twice__': unknown attribute
This is because of:
extern pid_t vfork(void) __RETURNS_TWICE;
It looks like there are other functions that are annotated with the same
attribute (getcontext, setjmp, etc.).
While I'm writing this email, I might as well point out a false positive
smatch told me about. I have a program that takes an year and month as a 6
digit number (e.g., 201501) and I want double check that it's valid. (The
first 4 digits look like a year and the last two digits look like a month
number.) Later on, I use the month part to index into an array of month
names. Here's a simplified test case:
#include <stdio.h>
#include <unistd.h>
static int validate_arch_id(int arch)
{
int y = arch / 100;
int m = arch % 100;
return (m >= 1) && (m <= 12) && (y >= 1970) && (y < 2100);
}
int main(int argc, char **argv)
{
static const char *months[12] = {
"January", "February", "March", "April", "May", "June",
"July", "August", "September", "October", "November",
"December",
};
int arch = 201201; /* test */
if (!validate_arch_id(arch))
arch = 197001;
printf("%s\n", months[(arch % 100) - 1]);
return 0;
}
I get the following error:
test.c:25 main() error: buffer overflow 'months' 12 <= 98
Obviously, smatch doesn't realize that given the validation and optional
assignment to 197001, it will never overflow.
Jeff.
[1] an opensolaris fork
--
Bad pun of the week: The formula 1 control computer suffered from a race
condition
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