newlib/winsup/cygwin/cygheap.cc

/* cygheap.cc: Cygwin heap manager.

   Copyright 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007 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 <assert.h>
#include <stdlib.h>
#include "cygerrno.h"
#include "security.h"
#include "path.h"
#include "fhandler.h"
#include "dtable.h"
#include "cygheap.h"
#include "child_info.h"
#include "heap.h"
#include "sync.h"
#include "sigproc.h"
#include "pinfo.h"
#include <unistd.h>

init_cygheap NO_COPY *cygheap;
void NO_COPY *cygheap_max;

extern "C" char  _cygheap_mid[] __attribute__((section(".cygheap")));
extern "C" char  _cygheap_end[];

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)) - (unsigned) (N0->data)))

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

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

/* Called by fork or spawn to reallocate cygwin heap */
void __stdcall
cygheap_fixup_in_child (bool execed)
{
  cygheap_max = child_proc_info->cygheap;
  cygheap = (init_cygheap *) cygheap_max;
  _csbrk ((char *) child_proc_info->cygheap_max - (char *) cygheap);
  child_copy (child_proc_info->parent, false, "cygheap", cygheap, cygheap_max, NULL);
  cygheap_init ();
  debug_fixup_after_fork_exec ();
  if (execed)
    {
      cygheap->hooks.next = NULL;
      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 */
	}
    }
}

int
init_cygheap::manage_console_count (const char *something, int amount, bool avoid_freeing_console)
{
  if (console_count == 0 && amount > 0)
    init_console_handler (true);
  console_count += amount;
  debug_printf ("%s: console_count %d, amount %d, %s, avoid_freeing_console %d",
		something, console_count, amount, myctty (), avoid_freeing_console);
  if (!avoid_freeing_console && amount <= 0 && !console_count && myself->ctty == -1)
    {
      BOOL res = FreeConsole ();
      debug_printf ("freed console, res %d", res);
      init_console_handler (false);
    }
  return console_count;
}

void
init_cygheap::close_ctty ()
{
  debug_printf ("closing cygheap->ctty %p", cygheap->ctty);
  cygheap->ctty->close ();
  cygheap->ctty = NULL;
}

#define nextpage(x) ((char *) (((DWORD) ((char *) x + granmask)) & ~granmask))
#define allocsize(x) ((DWORD) nextpage (x))
#ifdef DEBUGGING
#define somekinda_printf debug_printf
#else
#define somekinda_printf malloc_printf
#endif

static void *__stdcall
_csbrk (int sbs)
{
  void *prebrk = cygheap_max;
  size_t granmask = getpagesize () - 1;
  char *newbase = nextpage (prebrk);
  cygheap_max = (char *) cygheap_max + sbs;
  if (!sbs || (newbase >= cygheap_max) || (cygheap_max <= _cygheap_end))
    /* nothing to do */;
  else
    {
      if (prebrk <= _cygheap_end)
	newbase = _cygheap_end;

      DWORD adjsbs = allocsize ((char *) cygheap_max - newbase);
      if (!VirtualAlloc (newbase, adjsbs, MEM_COMMIT | MEM_RESERVE, PAGE_READWRITE))
	{
	  MEMORY_BASIC_INFORMATION m;
	  if (!VirtualQuery (newbase, &m, sizeof m))
	    system_printf ("couldn't get memory info, %E");
	  somekinda_printf ("Couldn't reserve/commit %d bytes of space for cygwin's heap, %E",
			    adjsbs);
	  somekinda_printf ("AllocationBase %p, BaseAddress %p, RegionSize %p, State %p\n",
			    m.AllocationBase, m.BaseAddress, m.RegionSize, m.State);
	  __seterrno ();
	  cygheap_max = (char *) cygheap_max - sbs;
	  return NULL;
	}
    }

  return prebrk;
}

extern "C" void __stdcall
cygheap_init ()
{
  cygheap_protect.init ("cygheap_protect");
  if (!cygheap)
    {
      cygheap = (init_cygheap *) memset (_cygheap_start, 0, _cygheap_mid - _cygheap_start);
      cygheap_max = cygheap;
      _csbrk (sizeof (*cygheap));
    }
  if (!cygheap->fdtab)
    cygheap->fdtab.init ();
  if (!cygheap->sigs)
    sigalloc ();

  /* TODO: This is plain wrong.  There's a difference between global shared
	   memory and every other global object.  It's still allowed to
	   create any global object from a process not having the
	   SE_CREATE_GLOBAL_NAME privilege.  It's only disallowed to create
	   global shared memory objects when not running in session 0 or
	   when not having the privilege.

	   The end result should look like this:
	   - All objects shared between multiple processes except shared
	     memory should always be created as global objects.
	   - Shared memory only needed locally should stick to being session
	     local.
	   - Every process should always try to create resp. open shared
	     memory as global.
	   - Only if that fails it should try to create the shared memory
	     as local shared memory, or ...
	   - ... the MS suggested workaround is to create a file backed shared
	     memory if a process has not the privilege to create global shared
	     memory.

	   However, this has to be planned carefully, especially given that
	   every single process creates its own (resp. the child's) shared
	   memory area with the process specific information. */
  if (!cygheap->shared_prefix)
    cygheap->shared_prefix = cstrdup (
	    wincap.has_terminal_services ()
	    && (set_privilege (hProcToken, SE_CREATE_GLOBAL_PRIV, true) >= 0
		|| GetLastError () == ERROR_NO_SUCH_PRIVILEGE)
	    ? "Global\\" : "");
}

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

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

static void *__stdcall
_cmalloc (unsigned 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; 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
    {
      rvc = (_cmalloc_entry *) _csbrk (sz + sizeof (_cmalloc_entry));
      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, unsigned size)
{
  void *newptr;
  if (ptr == NULL)
    newptr = _cmalloc (size);
  else
    {
      unsigned 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, unsigned len)
{
  if (!c)
    {
      set_errno (ENOMEM);
      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)
    {
#ifdef DEBUGGING
      system_printf ("cmalloc returned NULL");
      try_to_debug ();
#endif
    }
  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));
#ifdef DEBUGGING
  if (!c)
    system_printf ("crealloc returned NULL");
#endif
  return creturn (t, c, n);
}

extern "C" void __stdcall
cfree (void *s)
{
  assert (!inheap (s));
  _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);
#ifdef DEBUGGING
  if (!c)
    system_printf ("ccalloc returned NULL");
#endif
  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;
}

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);
}