/* $Id$ */


#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <asm/page.h>
#include <unistd.h>
#include <stdio.h>
#include <string.h>

#include "maps.h"
#include "common.h"
#include "hook.h"


struct range
  {
    void *start;
    void *end;
  };
/* FIXME: Dynamic allocation.  */
static struct range ranges[PAGE_SIZE * 8 / sizeof (struct range)];
static struct range *ranges_static_end = ranges;
static struct range *ranges_end = ranges;	/* = ranges_static_end */


/* Returns 0 on readable start..end-1.  */
/* TODO: Sort + binary search.  */
INTERNAL int maps_verify (void *start, void *end)
{
  int changed;

  do
    {
      struct range *range;

      changed = 0;
      for (range = ranges; start < end && range < ranges_end; range++)
	if (start >= range->start && start < range->end)
	  {
	    start = range->end;
	    changed = 1;
	  }
    }
  while (start < end && changed);

  if (start < end)
    return -1;
  /* Success.  */
  return 0;
}

INTERNAL void maps_static_setup (void *start, void *end)
{
  if (ranges_static_end >= ranges + N_ELEMENTS (ranges))
    return;

  ranges_static_end->start = start;
  ranges_static_end->end = end;
  ranges_static_end++;

  if (debug >= 1)
    fprintf (stderr,"static: %p - %p\n", start, end);
}

INTERNAL void maps_read (void)
{
  int fd;
  ssize_t bytes_read;
  char *s;

  /* Reset.  */
  ranges_end = ranges_static_end;

  /* Do not use level 3 I/O as it may be too SIGSEGV intrusive.  */
  fd = open (MAPS_FILENAME, O_RDONLY);
  if (fd == -1)
    return;
  bytes_read = read (fd, ranges_end, (char *) ranges + sizeof (ranges)
				     - (char *) ranges_end - 1);
  if (close (fd))
    return;
  if (bytes_read <= 0)
    return;
  s = (char *) ranges_end;
  s[bytes_read] = 0;

  while (*s)
    {
      unsigned long start, end;
      char prot_read, prot_write, prot_exec, prot_mayshare;
      int offset, i;
      const char *vdso_name = " [vdso]";
      const size_t vdso_len = strlen (vdso_name);

      i = sscanf (s, "%lx-%lx %c%c%c%c %n", &start, &end, &prot_read,
		  &prot_write, &prot_exec, &prot_mayshare, &offset);
      if (i != 6)
        break;
      s += offset;
      /* Reuse the trailing absolute pathname?
         Currently we use the relative one from dl_iterate_phdr(3).  */
      while (*s && *s != '\n')
        s++;
      /* Skip [vdso] entry to discard its dl_iterate_phdr(3) which has the
	 same name as the main executable - "".  */
      if (s >= (char *) ranges + vdso_len
	  && memcmp (s - vdso_len, vdso_name, vdso_len) == 0)
	continue;
      if (prot_read != 'r')
        continue;
      if (prot_write != '-')
        continue;
      if (prot_exec != 'x')
        continue;
      if (prot_mayshare != 'p')
        continue;
      ranges_end->start = (void *) start;
      ranges_end->end = (void *) end;
      ranges_end++;

      if (debug >= 1)
	fprintf (stderr,"range: %p - %p\n", (void *) start, (void *) end);

      if (ranges_end >= ranges + N_ELEMENTS (ranges))
	return;
    }
}