[ntk/apt.git] / apt-pkg / contrib / mmap.cc

// -*- mode: cpp; mode: fold -*-
// Description								/*{{{*/
// $Id: mmap.cc,v 1.22 2001/05/27 05:19:30 jgg Exp $
/* ######################################################################
   
   MMap Class - Provides 'real' mmap or a faked mmap using read().

   MMap cover class.

   Some broken versions of glibc2 (libc6) have a broken definition
   of mmap that accepts a char * -- all other systems (and libc5) use
   void *. We can't safely do anything here that would be portable, so
   libc6 generates warnings -- which should be errors, g++ isn't properly
   strict.
   
   ##################################################################### */
									/*}}}*/
// Include Files							/*{{{*/
#define _BSD_SOURCE
#include <apt-pkg/mmap.h>
#include <apt-pkg/error.h>

#include <apti18n.h>

#include <sys/mman.h>
#include <sys/stat.h>
#include <unistd.h>
#include <fcntl.h>
#include <stdlib.h>
#include <errno.h>

#include <cstring>
   									/*}}}*/

// MMap::MMap - Constructor						/*{{{*/
// ---------------------------------------------------------------------
/* */
MMap::MMap(FileFd &F,unsigned long Flags) : Flags(Flags), iSize(0),
                     Base(0), SyncToFd(NULL)
{
   if ((Flags & NoImmMap) != NoImmMap)
      Map(F);
}
									/*}}}*/
// MMap::MMap - Constructor						/*{{{*/
// ---------------------------------------------------------------------
/* */
MMap::MMap(unsigned long Flags) : Flags(Flags), iSize(0),
                     Base(0), SyncToFd(NULL)
{
}
									/*}}}*/
// MMap::~MMap - Destructor						/*{{{*/
// ---------------------------------------------------------------------
/* */
MMap::~MMap()
{
   Close();
}
									/*}}}*/
// MMap::Map - Perform the mapping					/*{{{*/
// ---------------------------------------------------------------------
/* */
bool MMap::Map(FileFd &Fd)
{
   iSize = Fd.Size();
   
   // Set the permissions.
   int Prot = PROT_READ;
   int Map = MAP_SHARED;
   if ((Flags & ReadOnly) != ReadOnly)
      Prot |= PROT_WRITE;
   if ((Flags & Public) != Public)
      Map = MAP_PRIVATE;
   
   if (iSize == 0)
      return _error->Error(_("Can't mmap an empty file"));
   
   // Map it.
   Base = mmap(0,iSize,Prot,Map,Fd.Fd(),0);
   if (Base == (void *)-1)
   {
      if (errno == ENODEV || errno == EINVAL)
      {
	 // The filesystem doesn't support this particular kind of mmap.
	 // So we allocate a buffer and read the whole file into it.
	 int const dupped_fd = dup(Fd.Fd());
	 if (dupped_fd == -1)
	    return _error->Errno("mmap", _("Couldn't duplicate file descriptor %i"), Fd.Fd());

	 Base = new unsigned char[iSize];
	 SyncToFd = new FileFd (dupped_fd);
	 if (!SyncToFd->Seek(0L) || !SyncToFd->Read(Base, iSize))
	    return false;
      }
      else
	 return _error->Errno("mmap",_("Couldn't make mmap of %lu bytes"),
	                      iSize);
     }

   return true;
}
									/*}}}*/
// MMap::Close - Close the map						/*{{{*/
// ---------------------------------------------------------------------
/* */
bool MMap::Close(bool DoSync)
{
   if ((Flags & UnMapped) == UnMapped || Base == 0 || iSize == 0)
      return true;
   
   if (DoSync == true)
      Sync();

   if (SyncToFd != NULL)
   {
      delete[] (char *)Base;
      delete SyncToFd;
      SyncToFd = NULL;
   }
   else
   {
      if (munmap((char *)Base, iSize) != 0)
	 _error->WarningE("mmap", _("Unable to close mmap"));
   }

   iSize = 0;
   Base = 0;
   return true;
}
									/*}}}*/
// MMap::Sync - Syncronize the map with the disk			/*{{{*/
// ---------------------------------------------------------------------
/* This is done in syncronous mode - the docs indicate that this will 
   not return till all IO is complete */
bool MMap::Sync()
{   
   if ((Flags & UnMapped) == UnMapped)
      return true;
   
#ifdef _POSIX_SYNCHRONIZED_IO   
   if ((Flags & ReadOnly) != ReadOnly)
   {
      if (SyncToFd != NULL)
      {
	 if (!SyncToFd->Seek(0) || !SyncToFd->Write(Base, iSize))
	    return false;
      }
      else
      {
	 if (msync((char *)Base, iSize, MS_SYNC) < 0)
	    return _error->Errno("msync", _("Unable to synchronize mmap"));
      }
   }
#endif   
   return true;
}
									/*}}}*/
// MMap::Sync - Syncronize a section of the file to disk		/*{{{*/
// ---------------------------------------------------------------------
/* */
bool MMap::Sync(unsigned long Start,unsigned long Stop)
{
   if ((Flags & UnMapped) == UnMapped)
      return true;
   
#ifdef _POSIX_SYNCHRONIZED_IO
   unsigned long PSize = sysconf(_SC_PAGESIZE);
   if ((Flags & ReadOnly) != ReadOnly)
   {
      if (SyncToFd != 0)
      {
	 if (!SyncToFd->Seek(0) ||
	     !SyncToFd->Write (((char *)Base)+Start, Stop-Start))
	    return false;
      }
      else
      {
	 if (msync((char *)Base+(int)(Start/PSize)*PSize,Stop - Start,MS_SYNC) < 0)
	    return _error->Errno("msync", _("Unable to synchronize mmap"));
      }
   }
#endif   
   return true;
}
									/*}}}*/

// DynamicMMap::DynamicMMap - Constructor				/*{{{*/
// ---------------------------------------------------------------------
/* */
DynamicMMap::DynamicMMap(FileFd &F,unsigned long Flags,unsigned long const &Workspace,
			 unsigned long const &Grow, unsigned long const &Limit) :
		MMap(F,Flags | NoImmMap), Fd(&F), WorkSpace(Workspace),
		GrowFactor(Grow), Limit(Limit)
{
   if (_error->PendingError() == true)
      return;
   
   unsigned long EndOfFile = Fd->Size();
   if (EndOfFile > WorkSpace)
      WorkSpace = EndOfFile;
   else if(WorkSpace > 0)
   {
      Fd->Seek(WorkSpace - 1);
      char C = 0;
      Fd->Write(&C,sizeof(C));
   }
   
   Map(F);
   iSize = EndOfFile;
}
									/*}}}*/
// DynamicMMap::DynamicMMap - Constructor for a non-file backed map	/*{{{*/
// ---------------------------------------------------------------------
/* We try here to use mmap to reserve some space - this is much more
   cooler than the fallback solution to simply allocate a char array
   and could come in handy later than we are able to grow such an mmap */
DynamicMMap::DynamicMMap(unsigned long Flags,unsigned long const &WorkSpace,
			 unsigned long const &Grow, unsigned long const &Limit) :
		MMap(Flags | NoImmMap | UnMapped), Fd(0), WorkSpace(WorkSpace),
		GrowFactor(Grow), Limit(Limit)
{
	if (_error->PendingError() == true)
		return;

	// disable Moveable if we don't grow
	if (Grow == 0)
		Flags &= ~Moveable;

#ifndef __linux__
	// kfreebsd doesn't have mremap, so we use the fallback
	if ((Flags & Moveable) == Moveable)
		Flags |= Fallback;
#endif

#ifdef _POSIX_MAPPED_FILES
	if ((Flags & Fallback) != Fallback) {
		// Set the permissions.
		int Prot = PROT_READ;
		int Map = MAP_PRIVATE | MAP_ANONYMOUS;
		if ((Flags & ReadOnly) != ReadOnly)
			Prot |= PROT_WRITE;
		if ((Flags & Public) == Public)
			Map = MAP_SHARED | MAP_ANONYMOUS;

		// use anonymous mmap() to get the memory
		Base = (unsigned char*) mmap(0, WorkSpace, Prot, Map, -1, 0);

		if(Base == MAP_FAILED)
			_error->Errno("DynamicMMap",_("Couldn't make mmap of %lu bytes"),WorkSpace);

		iSize = 0;
		return;
	}
#endif
	// fallback to a static allocated space
	Base = new unsigned char[WorkSpace];
	memset(Base,0,WorkSpace);
	iSize = 0;
}
									/*}}}*/
// DynamicMMap::~DynamicMMap - Destructor				/*{{{*/
// ---------------------------------------------------------------------
/* We truncate the file to the size of the memory data set */
DynamicMMap::~DynamicMMap()
{
   if (Fd == 0)
   {
#ifdef _POSIX_MAPPED_FILES
      munmap(Base, WorkSpace);
#else
      delete [] (unsigned char *)Base;
#endif
      return;
   }
   
   unsigned long EndOfFile = iSize;
   iSize = WorkSpace;
   Close(false);
   if(ftruncate(Fd->Fd(),EndOfFile) < 0)
      _error->Errno("ftruncate", _("Failed to truncate file"));
}  
									/*}}}*/
// DynamicMMap::RawAllocate - Allocate a raw chunk of unaligned space	/*{{{*/
// ---------------------------------------------------------------------
/* This allocates a block of memory aligned to the given size */
unsigned long DynamicMMap::RawAllocate(unsigned long Size,unsigned long Aln)
{
   unsigned long Result = iSize;
   if (Aln != 0)
      Result += Aln - (iSize%Aln);

   iSize = Result + Size;

   // try to grow the buffer
   while(Result + Size > WorkSpace)
   {
      if(!Grow())
      {
	 _error->Error(_("Dynamic MMap ran out of room. Please increase the size "
			 "of APT::Cache-Limit. Current value: %lu. (man 5 apt.conf)"), WorkSpace);
	 return 0;
      }
   }
   return Result;
}
									/*}}}*/
// DynamicMMap::Allocate - Pooled aligned allocation			/*{{{*/
// ---------------------------------------------------------------------
/* This allocates an Item of size ItemSize so that it is aligned to its
   size in the file. */
unsigned long DynamicMMap::Allocate(unsigned long ItemSize)
{
   // Look for a matching pool entry
   Pool *I;
   Pool *Empty = 0;
   for (I = Pools; I != Pools + PoolCount; I++)
   {
      if (I->ItemSize == 0)
	 Empty = I;
      if (I->ItemSize == ItemSize)
	 break;
   }
   // No pool is allocated, use an unallocated one
   if (I == Pools + PoolCount)
   {
      // Woops, we ran out, the calling code should allocate more.
      if (Empty == 0)
      {
	 _error->Error("Ran out of allocation pools");
	 return 0;
      }
      
      I = Empty;
      I->ItemSize = ItemSize;
      I->Count = 0;
   }

   unsigned long Result = 0;
   // Out of space, allocate some more
   if (I->Count == 0)
   {
      const unsigned long size = 20*1024;
      I->Count = size/ItemSize;
      Result = RawAllocate(size,ItemSize);
      // Does the allocation failed ?
      if (Result == 0 && _error->PendingError())
	 return 0;
      I->Start = Result;
   }
   else
      Result = I->Start;

   I->Count--;
   I->Start += ItemSize;
   return Result/ItemSize;
}
									/*}}}*/
// DynamicMMap::WriteString - Write a string to the file		/*{{{*/
// ---------------------------------------------------------------------
/* Strings are not aligned to anything */
unsigned long DynamicMMap::WriteString(const char *String,
				       unsigned long Len)
{
   if (Len == (unsigned long)-1)
      Len = strlen(String);

   unsigned long Result = RawAllocate(Len+1,0);

   if (Result == 0 && _error->PendingError())
      return 0;

   memcpy((char *)Base + Result,String,Len);
   ((char *)Base)[Result + Len] = 0;
   return Result;
}
									/*}}}*/
// DynamicMMap::Grow - Grow the mmap					/*{{{*/
// ---------------------------------------------------------------------
/* This method is a wrapper around different methods to (try to) grow
   a mmap (or our char[]-fallback). Encounterable environments:
   1. Moveable + !Fallback + linux -> mremap with MREMAP_MAYMOVE
   2. Moveable + !Fallback + !linux -> not possible (forbidden by constructor)
   3. Moveable + Fallback -> realloc
   4. !Moveable + !Fallback + linux -> mremap alone - which will fail in 99,9%
   5. !Moveable + !Fallback + !linux -> not possible (forbidden by constructor)
   6. !Moveable + Fallback -> not possible
   [ While Moveable and Fallback stands for the equally named flags and
     "linux" indicates a linux kernel instead of a freebsd kernel. ]
   So what you can see here is, that a MMAP which want to be growable need
   to be moveable to have a real chance but that this method will at least try
   the nearly impossible 4 to grow it before it finally give up: Never say never. */
bool DynamicMMap::Grow() {
	if (Limit != 0 && WorkSpace >= Limit)
		return _error->Error(_("Unable to increase the size of the MMap as the "
		                       "limit of %lu bytes is already reached."), Limit);

	unsigned long const newSize = WorkSpace + 1024*1024;

	if(Fd != 0) {
		Fd->Seek(newSize - 1);
		char C = 0;
		Fd->Write(&C,sizeof(C));
	}
	if ((Flags & Fallback) != Fallback) {
#if defined(_POSIX_MAPPED_FILES) && defined(__linux__)
   #ifdef MREMAP_MAYMOVE
		if ((Flags & Moveable) == Moveable)
			Base = mremap(Base, WorkSpace, newSize, MREMAP_MAYMOVE);
		else
   #endif
			Base = mremap(Base, WorkSpace, newSize, 0);

		if(Base == MAP_FAILED)
			return false;
#else
		return false;
#endif
	} else {
		if ((Flags & Moveable) != Moveable)
			return false;

		Base = realloc(Base, newSize);
		if (Base == NULL)
			return false;
	}

	WorkSpace = newSize;
	return true;
}
									/*}}}*/
Commit	Line	Data
578bfd0a AL	1	// -- mode: cpp; mode: fold --
578bfd0a AL	2	// Description /{{{/
0db4a45b	3	// $Id: mmap.cc,v 1.22 2001/05/27 05:19:30 jgg Exp $
578bfd0a AL	4	/* ######################################################################
	5
	6	MMap Class - Provides 'real' mmap or a faked mmap using read().
	7
	8	MMap cover class.
	9
	10	Some broken versions of glibc2 (libc6) have a broken definition
	11	of mmap that accepts a char * -- all other systems (and libc5) use
	12	void *. We can't safely do anything here that would be portable, so
	13	libc6 generates warnings -- which should be errors, g++ isn't properly
	14	strict.
	15
578bfd0a AL	16	##################################################################### */
	17	/}}}/
	18	// Include Files /{{{/
	19	#define _BSD_SOURCE
094a497d AL	20	#include <apt-pkg/mmap.h>
094a497d AL	21	#include <apt-pkg/error.h>
578bfd0a	22
b2e465d6 AL	23	#include <apti18n.h>
b2e465d6 AL	24
578bfd0a AL	25	#include <sys/mman.h>
578bfd0a AL	26	#include <sys/stat.h>
578bfd0a AL	27	#include <unistd.h>
578bfd0a AL	28	#include <fcntl.h>
13eb93fc	29	#include <stdlib.h>
06afffcc	30	#include <errno.h>
4f333a8b MV	31
4f333a8b MV	32	#include <cstring>
578bfd0a AL	33	/}}}/
	34
	35	// MMap::MMap - Constructor /{{{/
	36	// ---------------------------------------------------------------------
	37	/* */
2d11135a	38	MMap::MMap(FileFd &F,unsigned long Flags) : Flags(Flags), iSize(0),
06afffcc	39	Base(0), SyncToFd(NULL)
578bfd0a AL	40	{
578bfd0a AL	41	if ((Flags & NoImmMap) != NoImmMap)
2d11135a AL	42	Map(F);
	43	}
	44	/}}}/
	45	// MMap::MMap - Constructor /{{{/
	46	// ---------------------------------------------------------------------
	47	/* */
	48	MMap::MMap(unsigned long Flags) : Flags(Flags), iSize(0),
06afffcc	49	Base(0), SyncToFd(NULL)
2d11135a	50	{
578bfd0a AL	51	}
	52	/}}}/
	53	// MMap::~MMap - Destructor /{{{/
	54	// ---------------------------------------------------------------------
	55	/* */
	56	MMap::~MMap()
	57	{
2d11135a	58	Close();
578bfd0a AL	59	}
	60	/}}}/
	61	// MMap::Map - Perform the mapping /{{{/
	62	// ---------------------------------------------------------------------
	63	/* */
2d11135a	64	bool MMap::Map(FileFd &Fd)
578bfd0a AL	65	{
	66	iSize = Fd.Size();
	67
	68	// Set the permissions.
	69	int Prot = PROT_READ;
	70	int Map = MAP_SHARED;
	71	if ((Flags & ReadOnly) != ReadOnly)
	72	Prot \|= PROT_WRITE;
	73	if ((Flags & Public) != Public)
	74	Map = MAP_PRIVATE;
	75
b35d2f5f	76	if (iSize == 0)
b2e465d6	77	return _error->Error(_("Can't mmap an empty file"));
b35d2f5f	78
578bfd0a AL	79	// Map it.
	80	Base = mmap(0,iSize,Prot,Map,Fd.Fd(),0);
	81	if (Base == (void *)-1)
06afffcc DK	82	{
	83	if (errno == ENODEV \|\| errno == EINVAL)
	84	{
	85	// The filesystem doesn't support this particular kind of mmap.
	86	// So we allocate a buffer and read the whole file into it.
	87	int const dupped_fd = dup(Fd.Fd());
	88	if (dupped_fd == -1)
	89	return _error->Errno("mmap", _("Couldn't duplicate file descriptor %i"), Fd.Fd());
	90
	91	Base = new unsigned char[iSize];
	92	SyncToFd = new FileFd (dupped_fd);
	93	if (!SyncToFd->Seek(0L) \|\| !SyncToFd->Read(Base, iSize))
	94	return false;
	95	}
	96	else
	97	return _error->Errno("mmap",_("Couldn't make mmap of %lu bytes"),
	98	iSize);
	99	}
578bfd0a AL	100
	101	return true;
	102	}
	103	/}}}/
	104	// MMap::Close - Close the map /{{{/
	105	// ---------------------------------------------------------------------
	106	/* */
2d11135a	107	bool MMap::Close(bool DoSync)
578bfd0a	108	{
2d11135a	109	if ((Flags & UnMapped) == UnMapped \|\| Base == 0 \|\| iSize == 0)
578bfd0a	110	return true;
2d11135a	111
1164783d AL	112	if (DoSync == true)
1164783d AL	113	Sync();
06afffcc DK	114
	115	if (SyncToFd != NULL)
	116	{
	117	delete[] (char *)Base;
	118	delete SyncToFd;
	119	SyncToFd = NULL;
	120	}
	121	else
	122	{
	123	if (munmap((char *)Base, iSize) != 0)
	124	_error->WarningE("mmap", _("Unable to close mmap"));
	125	}
	126
578bfd0a	127	iSize = 0;
b2e465d6	128	Base = 0;
578bfd0a AL	129	return true;
	130	}
	131	/}}}/
	132	// MMap::Sync - Syncronize the map with the disk /{{{/
	133	// ---------------------------------------------------------------------
0149949b AL	134	/* This is done in syncronous mode - the docs indicate that this will
0149949b AL	135	not return till all IO is complete */
578bfd0a AL	136	bool MMap::Sync()
578bfd0a AL	137	{
2d11135a AL	138	if ((Flags & UnMapped) == UnMapped)
	139	return true;
	140
de3c15ea	141	#ifdef _POSIX_SYNCHRONIZED_IO
1164783d	142	if ((Flags & ReadOnly) != ReadOnly)
06afffcc DK	143	{
	144	if (SyncToFd != NULL)
	145	{
	146	if (!SyncToFd->Seek(0) \|\| !SyncToFd->Write(Base, iSize))
	147	return false;
	148	}
	149	else
	150	{
	151	if (msync((char *)Base, iSize, MS_SYNC) < 0)
	152	return _error->Errno("msync", _("Unable to synchronize mmap"));
	153	}
	154	}
de3c15ea	155	#endif
578bfd0a AL	156	return true;
	157	}
	158	/}}}/
	159	// MMap::Sync - Syncronize a section of the file to disk /{{{/
	160	// ---------------------------------------------------------------------
	161	/* */
	162	bool MMap::Sync(unsigned long Start,unsigned long Stop)
	163	{
2d11135a AL	164	if ((Flags & UnMapped) == UnMapped)
	165	return true;
	166
35c22def AL	167	#ifdef _POSIX_SYNCHRONIZED_IO
35c22def AL	168	unsigned long PSize = sysconf(_SC_PAGESIZE);
1164783d	169	if ((Flags & ReadOnly) != ReadOnly)
06afffcc DK	170	{
	171	if (SyncToFd != 0)
	172	{
	173	if (!SyncToFd->Seek(0) \|\|
	174	!SyncToFd->Write (((char *)Base)+Start, Stop-Start))
	175	return false;
	176	}
	177	else
	178	{
	179	if (msync((char )Base+(int)(Start/PSize)PSize,Stop - Start,MS_SYNC) < 0)
	180	return _error->Errno("msync", _("Unable to synchronize mmap"));
	181	}
	182	}
de3c15ea	183	#endif
578bfd0a AL	184	return true;
	185	}
	186	/}}}/
	187
	188	// DynamicMMap::DynamicMMap - Constructor /{{{/
	189	// ---------------------------------------------------------------------
	190	/* */
d6c4a976 DK	191	DynamicMMap::DynamicMMap(FileFd &F,unsigned long Flags,unsigned long const &Workspace,
	192	unsigned long const &Grow, unsigned long const &Limit) :
	193	MMap(F,Flags \| NoImmMap), Fd(&F), WorkSpace(Workspace),
	194	GrowFactor(Grow), Limit(Limit)
578bfd0a	195	{
d38b7b3d AL	196	if (_error->PendingError() == true)
	197	return;
	198
2d11135a	199	unsigned long EndOfFile = Fd->Size();
b2e465d6 AL	200	if (EndOfFile > WorkSpace)
b2e465d6 AL	201	WorkSpace = EndOfFile;
ea92d036	202	else if(WorkSpace > 0)
b2e465d6	203	{
ea92d036	204	Fd->Seek(WorkSpace - 1);
b2e465d6 AL	205	char C = 0;
	206	Fd->Write(&C,sizeof(C));
	207	}
	208
2d11135a	209	Map(F);
578bfd0a AL	210	iSize = EndOfFile;
	211	}
	212	/}}}/
2d11135a AL	213	// DynamicMMap::DynamicMMap - Constructor for a non-file backed map /{{{/
2d11135a AL	214	// ---------------------------------------------------------------------
f1c6a8ca DK	215	/* We try here to use mmap to reserve some space - this is much more
	216	cooler than the fallback solution to simply allocate a char array
	217	and could come in handy later than we are able to grow such an mmap */
d6c4a976 DK	218	DynamicMMap::DynamicMMap(unsigned long Flags,unsigned long const &WorkSpace,
	219	unsigned long const &Grow, unsigned long const &Limit) :
	220	MMap(Flags \| NoImmMap \| UnMapped), Fd(0), WorkSpace(WorkSpace),
	221	GrowFactor(Grow), Limit(Limit)
2d11135a	222	{
d6c4a976 DK	223	if (_error->PendingError() == true)
	224	return;
	225
	226	// disable Moveable if we don't grow
	227	if (Grow == 0)
	228	Flags &= ~Moveable;
	229
	230	#ifndef __linux__
	231	// kfreebsd doesn't have mremap, so we use the fallback
	232	if ((Flags & Moveable) == Moveable)
	233	Flags \|= Fallback;
	234	#endif
f1c6a8ca DK	235
f1c6a8ca DK	236	#ifdef _POSIX_MAPPED_FILES
d6c4a976 DK	237	if ((Flags & Fallback) != Fallback) {
	238	// Set the permissions.
	239	int Prot = PROT_READ;
	240	int Map = MAP_PRIVATE \| MAP_ANONYMOUS;
	241	if ((Flags & ReadOnly) != ReadOnly)
	242	Prot \|= PROT_WRITE;
	243	if ((Flags & Public) == Public)
	244	Map = MAP_SHARED \| MAP_ANONYMOUS;
eb162ff7	245
d6c4a976 DK	246	// use anonymous mmap() to get the memory
d6c4a976 DK	247	Base = (unsigned char*) mmap(0, WorkSpace, Prot, Map, -1, 0);
eb162ff7	248
d6c4a976 DK	249	if(Base == MAP_FAILED)
	250	_error->Errno("DynamicMMap",_("Couldn't make mmap of %lu bytes"),WorkSpace);
	251
	252	iSize = 0;
	253	return;
	254	}
d5972534	255	#endif
d6c4a976 DK	256	// fallback to a static allocated space
	257	Base = new unsigned char[WorkSpace];
	258	memset(Base,0,WorkSpace);
	259	iSize = 0;
2d11135a AL	260	}
2d11135a AL	261	/}}}/
578bfd0a AL	262	// DynamicMMap::~DynamicMMap - Destructor /{{{/
	263	// ---------------------------------------------------------------------
	264	/* We truncate the file to the size of the memory data set */
	265	DynamicMMap::~DynamicMMap()
	266	{
2d11135a AL	267	if (Fd == 0)
2d11135a AL	268	{
f1c6a8ca	269	#ifdef _POSIX_MAPPED_FILES
a67de73e	270	munmap(Base, WorkSpace);
f1c6a8ca	271	#else
2d11135a	272	delete [] (unsigned char *)Base;
f1c6a8ca	273	#endif
2d11135a AL	274	return;
	275	}
	276
578bfd0a	277	unsigned long EndOfFile = iSize;
1164783d	278	iSize = WorkSpace;
2d11135a	279	Close(false);
3c8cda8b MV	280	if(ftruncate(Fd->Fd(),EndOfFile) < 0)
3c8cda8b MV	281	_error->Errno("ftruncate", _("Failed to truncate file"));
578bfd0a AL	282	}
	283	/}}}/
	284	// DynamicMMap::RawAllocate - Allocate a raw chunk of unaligned space /{{{/
	285	// ---------------------------------------------------------------------
f55a958f AL	286	/* This allocates a block of memory aligned to the given size */
f55a958f AL	287	unsigned long DynamicMMap::RawAllocate(unsigned long Size,unsigned long Aln)
578bfd0a AL	288	{
578bfd0a AL	289	unsigned long Result = iSize;
f55a958f AL	290	if (Aln != 0)
f55a958f AL	291	Result += Aln - (iSize%Aln);
c5f44afc	292
f55a958f	293	iSize = Result + Size;
c5f44afc	294
f1c6a8ca DK	295	// try to grow the buffer
f1c6a8ca DK	296	while(Result + Size > WorkSpace)
578bfd0a	297	{
f1c6a8ca DK	298	if(!Grow())
	299	{
	300	_error->Error(_("Dynamic MMap ran out of room. Please increase the size "
	301	"of APT::Cache-Limit. Current value: %lu. (man 5 apt.conf)"), WorkSpace);
	302	return 0;
	303	}
578bfd0a	304	}
578bfd0a AL	305	return Result;
	306	}
	307	/}}}/
	308	// DynamicMMap::Allocate - Pooled aligned allocation /{{{/
	309	// ---------------------------------------------------------------------
	310	/* This allocates an Item of size ItemSize so that it is aligned to its
	311	size in the file. */
	312	unsigned long DynamicMMap::Allocate(unsigned long ItemSize)
c5f44afc	313	{
578bfd0a AL	314	// Look for a matching pool entry
	315	Pool *I;
	316	Pool *Empty = 0;
	317	for (I = Pools; I != Pools + PoolCount; I++)
	318	{
	319	if (I->ItemSize == 0)
	320	Empty = I;
	321	if (I->ItemSize == ItemSize)
	322	break;
	323	}
578bfd0a AL	324	// No pool is allocated, use an unallocated one
	325	if (I == Pools + PoolCount)
	326	{
	327	// Woops, we ran out, the calling code should allocate more.
	328	if (Empty == 0)
	329	{
	330	_error->Error("Ran out of allocation pools");
	331	return 0;
	332	}
	333
	334	I = Empty;
	335	I->ItemSize = ItemSize;
	336	I->Count = 0;
	337	}
c5f44afc DK	338
c5f44afc DK	339	unsigned long Result = 0;
578bfd0a AL	340	// Out of space, allocate some more
	341	if (I->Count == 0)
	342	{
c5f44afc DK	343	const unsigned long size = 20*1024;
	344	I->Count = size/ItemSize;
	345	Result = RawAllocate(size,ItemSize);
	346	// Does the allocation failed ?
	347	if (Result == 0 && _error->PendingError())
	348	return 0;
	349	I->Start = Result;
	350	}
	351	else
	352	Result = I->Start;
f55a958f	353
578bfd0a	354	I->Count--;
c5f44afc	355	I->Start += ItemSize;
578bfd0a AL	356	return Result/ItemSize;
	357	}
	358	/}}}/
	359	// DynamicMMap::WriteString - Write a string to the file /{{{/
	360	// ---------------------------------------------------------------------
	361	/* Strings are not aligned to anything */
	362	unsigned long DynamicMMap::WriteString(const char *String,
	363	unsigned long Len)
	364	{
6e52073f	365	if (Len == (unsigned long)-1)
578bfd0a	366	Len = strlen(String);
c5f44afc DK	367
	368	unsigned long Result = RawAllocate(Len+1,0);
	369
	370	if (Result == 0 && _error->PendingError())
	371	return 0;
	372
578bfd0a AL	373	memcpy((char *)Base + Result,String,Len);
	374	((char *)Base)[Result + Len] = 0;
	375	return Result;
	376	}
	377	/}}}/
f1c6a8ca DK	378	// DynamicMMap::Grow - Grow the mmap /{{{/
f1c6a8ca DK	379	// ---------------------------------------------------------------------
d6c4a976 DK	380	/* This method is a wrapper around different methods to (try to) grow
	381	a mmap (or our char[]-fallback). Encounterable environments:
	382	1. Moveable + !Fallback + linux -> mremap with MREMAP_MAYMOVE
	383	2. Moveable + !Fallback + !linux -> not possible (forbidden by constructor)
	384	3. Moveable + Fallback -> realloc
	385	4. !Moveable + !Fallback + linux -> mremap alone - which will fail in 99,9%
	386	5. !Moveable + !Fallback + !linux -> not possible (forbidden by constructor)
	387	6. !Moveable + Fallback -> not possible
	388	[ While Moveable and Fallback stands for the equally named flags and
	389	"linux" indicates a linux kernel instead of a freebsd kernel. ]
	390	So what you can see here is, that a MMAP which want to be growable need
	391	to be moveable to have a real chance but that this method will at least try
	392	the nearly impossible 4 to grow it before it finally give up: Never say never. */
	393	bool DynamicMMap::Grow() {
	394	if (Limit != 0 && WorkSpace >= Limit)
e3ac3b46 DK	395	return _error->Error(_("Unable to increase the size of the MMap as the "
e3ac3b46 DK	396	"limit of %lu bytes is already reached."), Limit);
f1c6a8ca	397
d6c4a976	398	unsigned long const newSize = WorkSpace + 1024*1024;
f1c6a8ca	399
d6c4a976 DK	400	if(Fd != 0) {
	401	Fd->Seek(newSize - 1);
	402	char C = 0;
	403	Fd->Write(&C,sizeof(C));
	404	}
	405	if ((Flags & Fallback) != Fallback) {
	406	#if defined(_POSIX_MAPPED_FILES) && defined(__linux__)
	407	#ifdef MREMAP_MAYMOVE
	408	if ((Flags & Moveable) == Moveable)
	409	Base = mremap(Base, WorkSpace, newSize, MREMAP_MAYMOVE);
	410	else
	411	#endif
	412	Base = mremap(Base, WorkSpace, newSize, 0);
f1c6a8ca	413
d6c4a976 DK	414	if(Base == MAP_FAILED)
d6c4a976 DK	415	return false;
f1c6a8ca	416	#else
d6c4a976	417	return false;
f1c6a8ca	418	#endif
d6c4a976 DK	419	} else {
	420	if ((Flags & Moveable) != Moveable)
	421	return false;
	422
	423	Base = realloc(Base, newSize);
	424	if (Base == NULL)
	425	return false;
	426	}
	427
	428	WorkSpace = newSize;
	429	return true;
f1c6a8ca DK	430	}
f1c6a8ca DK	431	/}}}/