sewardj | 024598e | 2008-09-18 14:43:05 +0000 | [diff] [blame] | 1 | |
| 2 | /* Check basic stack overflow detection. |
| 3 | |
| 4 | It's difficult to get consistent behaviour across all platforms. |
| 5 | For example, x86 w/ gcc-4.3.1 gives |
| 6 | |
| 7 | Expected: stack array "a" in frame 2 back from here |
| 8 | Actual: stack array "beforea" in frame 2 back from here |
| 9 | |
| 10 | whereas amd64 w/ gcc-4.3.1 gives |
| 11 | |
| 12 | Expected: stack array "a" in frame 2 back from here |
| 13 | Actual: unknown |
| 14 | |
| 15 | This happens because on x86 the arrays are placed on the |
| 16 | stack without holes in between, but not so for amd64. I don't |
| 17 | know why. |
| 18 | */ |
| 19 | |
| 20 | |
| 21 | #include <stdio.h> |
| 22 | |
| 23 | __attribute__((noinline)) void foo ( long* sa, int n ) |
| 24 | { |
| 25 | int i; |
| 26 | for (i = 0; i < n; i++) |
| 27 | sa[i] = 0; |
| 28 | } |
| 29 | |
| 30 | __attribute__((noinline)) void bar ( long* sa, int n ) |
| 31 | { |
| 32 | foo(sa, n); |
| 33 | } |
| 34 | |
| 35 | int main ( void ) |
| 36 | { |
| 37 | int i; |
| 38 | long beforea[3]; |
| 39 | long a[7]; |
| 40 | long aftera[3]; |
| 41 | bar(a, 7+1); /* generates error */ |
| 42 | bar(a, 7+0); /* generates no error */ |
| 43 | for (i = 0; i < 7+1; i++) { |
| 44 | a[i] = 0; |
| 45 | } |
njn | efc13c2 | 2009-02-23 06:44:51 +0000 | [diff] [blame] | 46 | {char beforebuf[8]; |
sewardj | 024598e | 2008-09-18 14:43:05 +0000 | [diff] [blame] | 47 | char buf[8]; |
| 48 | char afterbuf[8]; |
| 49 | sprintf(buf, "%d", 123456789); |
| 50 | return 1 & ((a[4] + beforea[1] + aftera[1] + beforebuf[1] |
| 51 | + buf[2] + afterbuf[3]) / 100000) ; |
njn | efc13c2 | 2009-02-23 06:44:51 +0000 | [diff] [blame] | 52 | } |
sewardj | 024598e | 2008-09-18 14:43:05 +0000 | [diff] [blame] | 53 | } |