none/tests/amd64/bug156404-amd64.c

   1
   2 /* Check that the main thread's stack, on Linux, is automatically
   3    extended down to the lowest valid address when a syscall happens.
   4    Failure to do so was causing this test to fail on Linux amd64. */
   5
   6 #include <unistd.h>
   7 #include <stdio.h>
   8 #include <stdlib.h>
   9 #include <assert.h>
  10
  11 #include <sys/syscall.h>
  12 #include <unistd.h>
  13
  14 #define VG_STRINGIFZ(__str)  #__str
  15 #define VG_STRINGIFY(__str)  VG_STRINGIFZ(__str)
  16
  17 #if defined(VGO_linux) || defined(VGO_darwin) || defined(VGO_freebsd)
  18 #if !defined(__NR_readlink)
  19 # define __NR_readlink 58
  20 #endif
  21
  22 #define __NR_READLINK        VG_STRINGIFY(__NR_readlink)
  23
  24 extern long my_readlink ( const char* path );
  25 asm(
  26 ".text\n"
  27 ".globl my_readlink\n"
  28 "my_readlink:\n"
  29 "\tsubq    $0x1008,%rsp\n"
  30 "\tmovq    %rdi,%rdi\n"              // path is in rdi
  31 "\tmovq    %rsp,%rsi\n"              // &buf[0] -> rsi
  32 "\tmovl    $0x1000,%edx\n"           // sizeof(buf) in rdx
  33 "\tmovl    $"__NR_READLINK",%eax\n"  // syscall number
  34 "\tsyscall\n"
  35 "\taddq    $0x1008,%rsp\n"
  36 "\tret\n"
  37 ".previous\n"
  38 );
  39
  40 #elif defined(VGO_solaris)
  41 #define __NR_READLINKAT      VG_STRINGIFY(SYS_readlinkat)
  42
  43 extern long my_readlink ( const char* path );
  44 asm(
  45 ".text\n"
  46 ".globl my_readlink\n"
  47 "my_readlink:\n"
  48 "\tsubq    $0x1008,%rsp\n"
  49 "\tmovq    %rdi,%rsi\n"
  50 "\txorq    %rdi,%rdi\n"
  51 "\tmovq    %rsp,%rdx\n"
  52 "\tmovq    $0x1000,%r10\n"
  53 "\tmovl    $"__NR_READLINKAT",%eax\n"
  54 "\tsyscall\n"
  55 "\taddq    $0x1008,%rsp\n"
  56 "\tret\n"
  57 ".previous\n"
  58 );
  59
  60 #else
  61 #error "Unknown OS"
  62 #endif
  63
  64 long recurse ( const char* path, long count )
  65 {
  66    if (count <= 0) {
  67       return my_readlink(path);
  68    } else {
  69       long r = recurse(path, count-1);
  70       return r;
  71    }
  72 }
  73
  74 int main ( void )
  75 {
  76    long i, r;
  77    for (i = 0; i < 2000; i++) {
  78       printf("depth %ld: ", i );
  79       r = recurse( "/proc/self", i );
  80       if (r > 1) r = 1; /* to make the output repeatable */
  81       assert(r >= 1);
  82       printf("r = %ld\n", r);
  83    }
  84    return 0;
  85 }