cygheap.cc

cygwin, 著名的在win32下模拟unix操作系统的东东

/* cygheap.cc: Cygwin heap manager.

   Copyright 2000, 2001, 2002 Red Hat, Inc.

   This file is part of Cygwin.

   This software is a copyrighted work licensed under the terms of the
   Cygwin license.  Please consult the file "CYGWIN_LICENSE" for
   details. */

#include "winsup.h"
#include <string.h>
#include <errno.h>
#include <assert.h>
#include <stdlib.h>
#include "security.h"
#include "fhandler.h"
#include "path.h"
#include "dtable.h"
#include "cygerrno.h"
#include "cygheap.h"
#include "child_info.h"
#include "heap.h"
#include "sync.h"
#include "shared_info.h"

init_cygheap NO_COPY *cygheap;
void NO_COPY *cygheap_max;

static NO_COPY muto *cygheap_protect;

struct cygheap_entry
  {
    int type;
    struct cygheap_entry *next;
    char data[0];
  };

#define NBUCKETS (sizeof (cygheap->buckets) / sizeof (cygheap->buckets[0]))
#define N0 ((_cmalloc_entry *) NULL)
#define to_cmalloc(s) ((_cmalloc_entry *) (((char *) (s)) - (int) (N0->data)))

#define CFMAP_OPTIONS (SEC_RESERVE | PAGE_READWRITE)
#define MVMAP_OPTIONS (FILE_MAP_WRITE)

extern "C" {
static void __stdcall _cfree (void *ptr) __attribute__((regparm(1)));
}

inline static void
init_cheap ()
{
  cygheap = (init_cygheap *) VirtualAlloc ((void *) &_cygheap_start, CYGHEAPSIZE, MEM_RESERVE, PAGE_NOACCESS);
  if (!cygheap)
    {
      MEMORY_BASIC_INFORMATION m;
      if (!VirtualQuery ((LPCVOID) &_cygheap_start, &m, sizeof m))
	system_printf ("couldn't get memory info, %E");
      system_printf ("Couldn't reserve space for cygwin's heap, %E");
      api_fatal ("AllocationBase %p, BaseAddress %p, RegionSize %p, State %p\n",
		 m.AllocationBase, m.BaseAddress, m.RegionSize, m.State);
    }
  cygheap_max = cygheap;
}

static void dup_now (void *, child_info *, unsigned) __attribute__ ((regparm(3)));
static void
dup_now (void *newcygheap, child_info *ci, unsigned n)
{
  if (!VirtualAlloc (newcygheap, n, MEM_COMMIT, PAGE_READWRITE))
    api_fatal ("couldn't allocate new cygwin heap %p, %d for child, %E",
	       newcygheap, n);
  memcpy (newcygheap, cygheap, n);
}

void *__stdcall
cygheap_setup_for_child (child_info *ci, bool dup_later)
{
  void *newcygheap;
  cygheap_protect->acquire ();
  unsigned n = (char *) cygheap_max - (char *) cygheap;
  unsigned size = CYGHEAPSIZE;
  if (size < n)
    size = n + (128 * 1024);
  ci->cygheap_h = CreateFileMapping (INVALID_HANDLE_VALUE, &sec_none,
				     CFMAP_OPTIONS, 0, size, NULL);
  if (!ci->cygheap_h)
    api_fatal ("Couldn't create heap for child, size %d, %E", CYGHEAPSIZE);
  newcygheap = MapViewOfFileEx (ci->cygheap_h, MVMAP_OPTIONS, 0, 0, 0, NULL);
  ProtectHandle1INH (ci->cygheap_h, passed_cygheap_h);
  if (!dup_later)
    dup_now (newcygheap, ci, n);
  cygheap_protect->release ();
  ci->cygheap = cygheap;
  ci->cygheap_max = cygheap_max;
  return newcygheap;
}

void __stdcall
cygheap_setup_for_child_cleanup (void *newcygheap, child_info *ci,
				 bool dup_it_now)
{
  if (dup_it_now)
    {
      /* NOTE: There is an assumption here that cygheap_max has not changed
	 between the time that cygheap_setup_for_child was called and now.
	 Make sure that this is a correct assumption.  */
      cygheap_protect->acquire ();
      dup_now (newcygheap, ci, (char *) cygheap_max - (char *) cygheap);
      cygheap_protect->release ();
    }
  UnmapViewOfFile (newcygheap);
  ForceCloseHandle1 (ci->cygheap_h, passed_cygheap_h);
}

/* Called by fork or spawn to reallocate cygwin heap */
void __stdcall
cygheap_fixup_in_child (bool execed)
{
  cygheap = child_proc_info->cygheap;
  cygheap_max = child_proc_info->cygheap_max;
  void *addr = !wincap.map_view_of_file_ex_sucks () ? cygheap : NULL;
  void *newaddr;

  newaddr = MapViewOfFileEx (child_proc_info->cygheap_h, MVMAP_OPTIONS, 0, 0, 0, addr);
  if (newaddr != cygheap)
    {
      if (!newaddr)
	newaddr = MapViewOfFileEx (child_proc_info->cygheap_h, MVMAP_OPTIONS, 0, 0, 0, NULL);
      DWORD n = (DWORD) cygheap_max - (DWORD) cygheap;
      /* Reserve cygwin heap in same spot as parent */
      if (!VirtualAlloc (cygheap, CYGHEAPSIZE, MEM_RESERVE, PAGE_NOACCESS))
	{
	  MEMORY_BASIC_INFORMATION m;
	  memset (&m, 0, sizeof m);
	  if (!VirtualQuery ((LPCVOID) cygheap, &m, sizeof m))
	    system_printf ("couldn't get memory info, %E");

	  system_printf ("Couldn't reserve space for cygwin's heap (%p <%p>) in child, %E", cygheap, newaddr);
	  api_fatal ("m.AllocationBase %p, m.BaseAddress %p, m.RegionSize %p, m.State %p\n",
		     m.AllocationBase, m.BaseAddress, m.RegionSize, m.State);
	}

      /* Allocate same amount of memory as parent */
      if (!VirtualAlloc (cygheap, n, MEM_COMMIT, PAGE_READWRITE))
	api_fatal ("Couldn't allocate space for child's heap %p, size %d, %E",
		   cygheap, n);
      memcpy (cygheap, newaddr, n);
      UnmapViewOfFile (newaddr);
    }

  ForceCloseHandle1 (child_proc_info->cygheap_h, passed_cygheap_h);

  cygheap_init ();
  debug_fixup_after_fork_exec ();

  if (execed)
    {
      cygheap->user_heap.base = NULL;		/* We can allocate the heap anywhere */
      /* Walk the allocated memory chain looking for orphaned memory from
	 previous execs */
      for (_cmalloc_entry *rvc = cygheap->chain; rvc; rvc = rvc->prev)
	{
	  cygheap_entry *ce = (cygheap_entry *) rvc->data;
	  if (!rvc->ptr || rvc->b >= NBUCKETS || ce->type <= HEAP_1_START)
	    continue;
	  else if (ce->type < HEAP_1_MAX)
	    ce->type += HEAP_1_MAX;	/* Mark for freeing after next exec */
	  else
	    _cfree (ce);		/* Marked by parent for freeing in child */
	}
    }
}

#define pagetrunc(x) ((void *) (((DWORD) (x)) & ~(4096 - 1)))

static void *__stdcall
_csbrk (int sbs)
{
  void *prebrk = cygheap_max;
  void *prebrka = pagetrunc (prebrk);
  (char *) cygheap_max += sbs;
  if (!sbs || (prebrk != prebrka && prebrka == pagetrunc (cygheap_max)))
    /* nothing to do */;
  else if (!VirtualAlloc (prebrk, (DWORD) sbs, MEM_COMMIT, PAGE_READWRITE))
    {
      malloc_printf ("couldn't commit memory for cygwin heap, %E");
      __seterrno ();
      (char *) cygheap_max -= sbs;
      return NULL;
    }

  return prebrk;
}

extern "C" void __stdcall
cygheap_init ()
{
  new_muto (cygheap_protect);
  if (!cygheap)
    {
      init_cheap ();
      (void) _csbrk (sizeof (*cygheap));
    }
  if (!cygheap->fdtab)
    cygheap->fdtab.init ();
}

/* Copyright (C) 1997, 2000 DJ Delorie */

static void *_cmalloc (int size) __attribute ((regparm(1)));
static void *__stdcall _crealloc (void *ptr, int size) __attribute ((regparm(2)));

static void *__stdcall
_cmalloc (int size)
{
  _cmalloc_entry *rvc;
  unsigned b, sz;

  /* Calculate "bit bucket" and size as a power of two. */
  for (b = 3, sz = 8; sz && sz < (size + sizeof (_cmalloc_entry));
       b++, sz <<= 1)
    continue;

  cygheap_protect->acquire ();
  if (cygheap->buckets[b])
    {
      rvc = (_cmalloc_entry *) cygheap->buckets[b];
      cygheap->buckets[b] = rvc->ptr;
      rvc->b = b;
    }
  else
    {
      size = sz + sizeof (_cmalloc_entry);
      rvc = (_cmalloc_entry *) _csbrk (size);
      if (!rvc)
	{
	  cygheap_protect->release ();
	  return NULL;
	}

      rvc->b = b;
      rvc->prev = cygheap->chain;
      cygheap->chain = rvc;
    }
  cygheap_protect->release ();
  return rvc->data;
}

static void __stdcall
_cfree (void *ptr)
{
  cygheap_protect->acquire ();
  _cmalloc_entry *rvc = to_cmalloc (ptr);
  DWORD b = rvc->b;
  rvc->ptr = cygheap->buckets[b];
  cygheap->buckets[b] = (char *) rvc;
  cygheap_protect->release ();
}

static void *__stdcall _crealloc (void *ptr, int size) __attribute__((regparm(2)));
static void *__stdcall
_crealloc (void *ptr, int size)
{
  void *newptr;
  if (ptr == NULL)
    newptr = _cmalloc (size);
  else
    {
      int oldsize = 1 << to_cmalloc (ptr)->b;
      if (size <= oldsize)
	return ptr;
      newptr = _cmalloc (size);
      memcpy (newptr, ptr, oldsize);
      _cfree (ptr);
    }
  return newptr;
}

/* End Copyright (C) 1997 DJ Delorie */

#define sizeof_cygheap(n) ((n) + sizeof (cygheap_entry))

#define N ((cygheap_entry *) NULL)
#define tocygheap(s) ((cygheap_entry *) (((char *) (s)) - (int) (N->data)))

inline static void *
creturn (cygheap_types x, cygheap_entry * c, int len)
{
  if (!c)
    {
      __seterrno ();
      return NULL;
    }
  c->type = x;
  char *cend = ((char *) c + sizeof (*c) + len);
  if (cygheap_max < cend)
    cygheap_max = cend;
  MALLOC_CHECK;
  return (void *) c->data;
}

extern "C" void *__stdcall
cmalloc (cygheap_types x, DWORD n)
{
  cygheap_entry *c;
  MALLOC_CHECK;
  c = (cygheap_entry *) _cmalloc (sizeof_cygheap (n));
  if (!c)
    system_printf ("cmalloc returned NULL");
  return creturn (x, c, n);
}

extern "C" void *__stdcall
crealloc (void *s, DWORD n)
{
  MALLOC_CHECK;
  if (s == NULL)
    return cmalloc (HEAP_STR, n);	// kludge

  assert (!inheap (s));
  cygheap_entry *c = tocygheap (s);
  cygheap_types t = (cygheap_types) c->type;
  c = (cygheap_entry *) _crealloc (c, sizeof_cygheap (n));
  if (!c)
    system_printf ("crealloc returned NULL");
  return creturn (t, c, n);
}

extern "C" void __stdcall
cfree (void *s)
{
  assert (!inheap (s));
  (void) _cfree (tocygheap (s));
  MALLOC_CHECK;
}

extern "C" void __stdcall
cfree_and_set (char *&s, char *what)
{
  if (s && s != almost_null)
    cfree (s);
  s = what;
}

extern "C" void *__stdcall
ccalloc (cygheap_types x, DWORD n, DWORD size)
{
  cygheap_entry *c;
  MALLOC_CHECK;
  n *= size;
  c = (cygheap_entry *) _cmalloc (sizeof_cygheap (n));
  if (c)
    memset (c->data, 0, n);
  if (!c)
    system_printf ("ccalloc returned NULL");
  return creturn (x, c, n);
}

extern "C" char *__stdcall
cstrdup (const char *s)
{
  MALLOC_CHECK;
  char *p = (char *) cmalloc (HEAP_STR, strlen (s) + 1);
  if (!p)
    return NULL;
  strcpy (p, s);
  MALLOC_CHECK;
  return p;
}

extern "C" char *__stdcall
cstrdup1 (const char *s)
{
  MALLOC_CHECK;
  char *p = (char *) cmalloc (HEAP_1_STR, strlen (s) + 1);
  if (!p)
    return NULL;
  strcpy (p, s);
  MALLOC_CHECK;
  return p;
}

bool
init_cygheap::etc_changed ()
{
  bool res = 0;

  if (!etc_changed_h)
    {
      path_conv pwd ("/etc");
      etc_changed_h = FindFirstChangeNotification (pwd, FALSE,
					      FILE_NOTIFY_CHANGE_LAST_WRITE);
      if (etc_changed_h == INVALID_HANDLE_VALUE)
	system_printf ("Can't open /etc for checking, %E", (char *) pwd,
		       etc_changed_h);
      else if (!DuplicateHandle (hMainProc, etc_changed_h, hMainProc,
				 &etc_changed_h, 0, TRUE,
				 DUPLICATE_SAME_ACCESS | DUPLICATE_CLOSE_SOURCE))
	{
	  system_printf ("Can't inherit /etc handle, %E", (char *) pwd,
			 etc_changed_h);
	  etc_changed_h = INVALID_HANDLE_VALUE;
	}
    }

   if (etc_changed_h != INVALID_HANDLE_VALUE
       && WaitForSingleObject (etc_changed_h, 0) == WAIT_OBJECT_0)
     {
       (void) FindNextChangeNotification (etc_changed_h);
       res = 1;
     }

  return res;
}

void
cygheap_root::set (const char *posix, const char *native)
{
  if (*posix == '/' && posix[1] == '\0')
    {
      if (m)
	{
	  cfree (m);
	  m = NULL;
	}
      return;
    }
  if (!m)
    m = (struct cygheap_root_mount_info *) ccalloc (HEAP_MOUNT, 1, sizeof (*m));
  strcpy (m->posix_path, posix);
  m->posix_pathlen = strlen (posix);
  if (m->posix_pathlen >= 1 && m->posix_path[m->posix_pathlen - 1] == '/')
    m->posix_path[--m->posix_pathlen] = '\0';

  strcpy (m->native_path, native);
  m->native_pathlen = strlen (native);
  if (m->native_pathlen >= 1 && m->native_path[m->native_pathlen - 1] == '\\')
    m->native_path[--m->native_pathlen] = '\0';
}

cygheap_user::~cygheap_user ()
{
#if 0
  if (pname)
    cfree (pname);
  if (plogsrv)
    cfree (plogsrv - 2);
  if (pdomain)
    cfree (pdomain);
  if (psid)
    cfree (psid);
#endif
}

void
cygheap_user::set_name (const char *new_name)
{
  bool allocated = !!pname;

  if (allocated)
    {
      if (strcasematch (new_name, pname))
	return;
      cfree (pname);
    }

  pname = cstrdup (new_name ? new_name : "");
  if (!allocated)
    return;		/* Initializing.  Don't bother with other stuff. */

  cfree_and_set (homedrive);
  cfree_and_set (homepath);
  cfree_and_set (plogsrv);
  cfree_and_set (pdomain);
  cfree_and_set (pwinname);
}

BOOL
cygheap_user::set_sid (PSID new_sid)
{
  if (new_sid)
    {
      if (!psid)
	psid = cmalloc (HEAP_STR, MAX_SID_LEN);
      if (psid)
	return CopySid (MAX_SID_LEN, psid, new_sid);
    }
  return FALSE;
}

BOOL
cygheap_user::set_orig_sid ()
{
  if (psid)
    {
      if (!orig_psid) orig_psid = cmalloc (HEAP_STR, MAX_SID_LEN);
      if (orig_psid)
	  return CopySid (MAX_SID_LEN, orig_psid, psid);
    }
  return FALSE;
}