[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 <config.h>

#include <apt-pkg/mmap.h>
#include <apt-pkg/error.h>
#include <apt-pkg/fileutl.h>

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

#include <apti18n.h>
									/*}}}*/

// 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 %llu bytes"),
	                      iSize);
     }

   return true;
}
									/*}}}*/
// MMap::Close - Close the map						/*{{{*/
// ---------------------------------------------------------------------
/* */
bool MMap::Close(bool DoSync)
{
   if ((Flags & UnMapped) == UnMapped || validData() == false || 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 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+(unsigned long long)(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 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)
		this->Flags &= ~Moveable;

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

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

		// 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)
   {
      if (validData() == false)
	 return;
#ifdef _POSIX_MAPPED_FILES
      munmap(Base, WorkSpace);
#else
      delete [] (unsigned char *)Base;
#endif
      return;
   }
   
   unsigned long 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 long Size,unsigned long Aln)
{
   unsigned long 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->Fatal(_("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;
      Pool* oldPools = Pools;
      Result = RawAllocate(size,ItemSize);
      if (Pools != oldPools)
	 I += Pools - oldPools;

      // 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 const 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);
	if (GrowFactor <= 0)
		return _error->Error(_("Unable to increase size of the MMap as automatic growing is disabled by user."));

	unsigned long long const newSize = WorkSpace + GrowFactor;

	if(Fd != 0) {
		Fd->Seek(newSize - 1);
		char C = 0;
		Fd->Write(&C,sizeof(C));
	}

	unsigned long const poolOffset = Pools - ((Pool*) Base);

	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;
	}

	Pools =(Pool*) Base + poolOffset;
	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
ea542140 DK	20	#include <config.h>
ea542140 DK	21
094a497d AL	22	#include <apt-pkg/mmap.h>
094a497d AL	23	#include <apt-pkg/error.h>
472ff00e	24	#include <apt-pkg/fileutl.h>
578bfd0a AL	25
	26	#include <sys/mman.h>
	27	#include <sys/stat.h>
578bfd0a AL	28	#include <unistd.h>
578bfd0a AL	29	#include <fcntl.h>
13eb93fc	30	#include <stdlib.h>
06afffcc	31	#include <errno.h>
4f333a8b	32	#include <cstring>
ea542140 DK	33
	34	#include <apti18n.h>
	35	/}}}/
578bfd0a AL	36
	37	// MMap::MMap - Constructor /{{{/
	38	// ---------------------------------------------------------------------
	39	/* */
2d11135a	40	MMap::MMap(FileFd &F,unsigned long Flags) : Flags(Flags), iSize(0),
06afffcc	41	Base(0), SyncToFd(NULL)
578bfd0a AL	42	{
578bfd0a AL	43	if ((Flags & NoImmMap) != NoImmMap)
2d11135a AL	44	Map(F);
	45	}
	46	/}}}/
	47	// MMap::MMap - Constructor /{{{/
	48	// ---------------------------------------------------------------------
	49	/* */
	50	MMap::MMap(unsigned long Flags) : Flags(Flags), iSize(0),
06afffcc	51	Base(0), SyncToFd(NULL)
2d11135a	52	{
578bfd0a AL	53	}
	54	/}}}/
	55	// MMap::~MMap - Destructor /{{{/
	56	// ---------------------------------------------------------------------
	57	/* */
	58	MMap::~MMap()
	59	{
2d11135a	60	Close();
578bfd0a AL	61	}
	62	/}}}/
	63	// MMap::Map - Perform the mapping /{{{/
	64	// ---------------------------------------------------------------------
	65	/* */
2d11135a	66	bool MMap::Map(FileFd &Fd)
578bfd0a AL	67	{
	68	iSize = Fd.Size();
	69
	70	// Set the permissions.
	71	int Prot = PROT_READ;
	72	int Map = MAP_SHARED;
	73	if ((Flags & ReadOnly) != ReadOnly)
	74	Prot \|= PROT_WRITE;
	75	if ((Flags & Public) != Public)
	76	Map = MAP_PRIVATE;
	77
b35d2f5f	78	if (iSize == 0)
b2e465d6	79	return _error->Error(_("Can't mmap an empty file"));
b35d2f5f	80
578bfd0a AL	81	// Map it.
	82	Base = mmap(0,iSize,Prot,Map,Fd.Fd(),0);
	83	if (Base == (void *)-1)
06afffcc DK	84	{
	85	if (errno == ENODEV \|\| errno == EINVAL)
	86	{
	87	// The filesystem doesn't support this particular kind of mmap.
	88	// So we allocate a buffer and read the whole file into it.
	89	int const dupped_fd = dup(Fd.Fd());
	90	if (dupped_fd == -1)
	91	return _error->Errno("mmap", _("Couldn't duplicate file descriptor %i"), Fd.Fd());
	92
	93	Base = new unsigned char[iSize];
	94	SyncToFd = new FileFd (dupped_fd);
	95	if (!SyncToFd->Seek(0L) \|\| !SyncToFd->Read(Base, iSize))
	96	return false;
	97	}
	98	else
650faab0	99	return _error->Errno("mmap",_("Couldn't make mmap of %llu bytes"),
06afffcc DK	100	iSize);
06afffcc DK	101	}
578bfd0a AL	102
	103	return true;
	104	}
	105	/}}}/
	106	// MMap::Close - Close the map /{{{/
	107	// ---------------------------------------------------------------------
	108	/* */
2d11135a	109	bool MMap::Close(bool DoSync)
578bfd0a	110	{
2a79d5b5	111	if ((Flags & UnMapped) == UnMapped \|\| validData() == false \|\| iSize == 0)
578bfd0a	112	return true;
2d11135a	113
1164783d AL	114	if (DoSync == true)
1164783d AL	115	Sync();
06afffcc DK	116
	117	if (SyncToFd != NULL)
	118	{
	119	delete[] (char *)Base;
	120	delete SyncToFd;
	121	SyncToFd = NULL;
	122	}
	123	else
	124	{
	125	if (munmap((char *)Base, iSize) != 0)
	126	_error->WarningE("mmap", _("Unable to close mmap"));
	127	}
	128
578bfd0a	129	iSize = 0;
b2e465d6	130	Base = 0;
578bfd0a AL	131	return true;
	132	}
	133	/}}}/
	134	// MMap::Sync - Syncronize the map with the disk /{{{/
	135	// ---------------------------------------------------------------------
0149949b AL	136	/* This is done in syncronous mode - the docs indicate that this will
0149949b AL	137	not return till all IO is complete */
578bfd0a AL	138	bool MMap::Sync()
578bfd0a AL	139	{
2d11135a AL	140	if ((Flags & UnMapped) == UnMapped)
	141	return true;
	142
de3c15ea	143	#ifdef _POSIX_SYNCHRONIZED_IO
1164783d	144	if ((Flags & ReadOnly) != ReadOnly)
06afffcc DK	145	{
	146	if (SyncToFd != NULL)
	147	{
	148	if (!SyncToFd->Seek(0) \|\| !SyncToFd->Write(Base, iSize))
	149	return false;
	150	}
	151	else
	152	{
	153	if (msync((char *)Base, iSize, MS_SYNC) < 0)
	154	return _error->Errno("msync", _("Unable to synchronize mmap"));
	155	}
	156	}
de3c15ea	157	#endif
578bfd0a AL	158	return true;
	159	}
	160	/}}}/
	161	// MMap::Sync - Syncronize a section of the file to disk /{{{/
	162	// ---------------------------------------------------------------------
	163	/* */
	164	bool MMap::Sync(unsigned long Start,unsigned long Stop)
	165	{
2d11135a AL	166	if ((Flags & UnMapped) == UnMapped)
	167	return true;
	168
35c22def	169	#ifdef _POSIX_SYNCHRONIZED_IO
650faab0	170	unsigned long long PSize = sysconf(_SC_PAGESIZE);
1164783d	171	if ((Flags & ReadOnly) != ReadOnly)
06afffcc DK	172	{
	173	if (SyncToFd != 0)
	174	{
	175	if (!SyncToFd->Seek(0) \|\|
	176	!SyncToFd->Write (((char *)Base)+Start, Stop-Start))
	177	return false;
	178	}
	179	else
	180	{
650faab0	181	if (msync((char )Base+(unsigned long long)(Start/PSize)PSize,Stop - Start,MS_SYNC) < 0)
06afffcc DK	182	return _error->Errno("msync", _("Unable to synchronize mmap"));
	183	}
	184	}
de3c15ea	185	#endif
578bfd0a AL	186	return true;
	187	}
	188	/}}}/
	189
	190	// DynamicMMap::DynamicMMap - Constructor /{{{/
	191	// ---------------------------------------------------------------------
	192	/* */
d6c4a976 DK	193	DynamicMMap::DynamicMMap(FileFd &F,unsigned long Flags,unsigned long const &Workspace,
	194	unsigned long const &Grow, unsigned long const &Limit) :
	195	MMap(F,Flags \| NoImmMap), Fd(&F), WorkSpace(Workspace),
	196	GrowFactor(Grow), Limit(Limit)
578bfd0a	197	{
d38b7b3d AL	198	if (_error->PendingError() == true)
	199	return;
	200
650faab0	201	unsigned long long EndOfFile = Fd->Size();
b2e465d6 AL	202	if (EndOfFile > WorkSpace)
b2e465d6 AL	203	WorkSpace = EndOfFile;
ea92d036	204	else if(WorkSpace > 0)
b2e465d6	205	{
ea92d036	206	Fd->Seek(WorkSpace - 1);
b2e465d6 AL	207	char C = 0;
	208	Fd->Write(&C,sizeof(C));
	209	}
	210
2d11135a	211	Map(F);
578bfd0a AL	212	iSize = EndOfFile;
	213	}
	214	/}}}/
2d11135a AL	215	// DynamicMMap::DynamicMMap - Constructor for a non-file backed map /{{{/
2d11135a AL	216	// ---------------------------------------------------------------------
f1c6a8ca DK	217	/* We try here to use mmap to reserve some space - this is much more
	218	cooler than the fallback solution to simply allocate a char array
	219	and could come in handy later than we are able to grow such an mmap */
d6c4a976 DK	220	DynamicMMap::DynamicMMap(unsigned long Flags,unsigned long const &WorkSpace,
	221	unsigned long const &Grow, unsigned long const &Limit) :
	222	MMap(Flags \| NoImmMap \| UnMapped), Fd(0), WorkSpace(WorkSpace),
	223	GrowFactor(Grow), Limit(Limit)
2d11135a	224	{
d6c4a976 DK	225	if (_error->PendingError() == true)
	226	return;
	227
	228	// disable Moveable if we don't grow
	229	if (Grow == 0)
a9fe5928	230	this->Flags &= ~Moveable;
d6c4a976 DK	231
	232	#ifndef __linux__
	233	// kfreebsd doesn't have mremap, so we use the fallback
a9fe5928 DK	234	if ((this->Flags & Moveable) == Moveable)
a9fe5928 DK	235	this->Flags \|= Fallback;
d6c4a976	236	#endif
f1c6a8ca DK	237
f1c6a8ca DK	238	#ifdef _POSIX_MAPPED_FILES
a9fe5928	239	if ((this->Flags & Fallback) != Fallback) {
d6c4a976 DK	240	// Set the permissions.
d6c4a976 DK	241	int Prot = PROT_READ;
f895e2ce	242	#ifdef MAP_ANONYMOUS
d6c4a976	243	int Map = MAP_PRIVATE \| MAP_ANONYMOUS;
f895e2ce DK	244	#else
	245	int Map = MAP_PRIVATE \| MAP_ANON;
	246	#endif
a9fe5928	247	if ((this->Flags & ReadOnly) != ReadOnly)
d6c4a976	248	Prot \|= PROT_WRITE;
a9fe5928	249	if ((this->Flags & Public) == Public)
f895e2ce	250	#ifdef MAP_ANONYMOUS
d6c4a976	251	Map = MAP_SHARED \| MAP_ANONYMOUS;
f895e2ce DK	252	#else
	253	Map = MAP_SHARED \| MAP_ANON;
	254	#endif
eb162ff7	255
d6c4a976 DK	256	// use anonymous mmap() to get the memory
d6c4a976 DK	257	Base = (unsigned char*) mmap(0, WorkSpace, Prot, Map, -1, 0);
eb162ff7	258
d6c4a976 DK	259	if(Base == MAP_FAILED)
	260	_error->Errno("DynamicMMap",_("Couldn't make mmap of %lu bytes"),WorkSpace);
	261
	262	iSize = 0;
	263	return;
	264	}
d5972534	265	#endif
d6c4a976 DK	266	// fallback to a static allocated space
	267	Base = new unsigned char[WorkSpace];
	268	memset(Base,0,WorkSpace);
	269	iSize = 0;
2d11135a AL	270	}
2d11135a AL	271	/}}}/
578bfd0a AL	272	// DynamicMMap::~DynamicMMap - Destructor /{{{/
	273	// ---------------------------------------------------------------------
	274	/* We truncate the file to the size of the memory data set */
	275	DynamicMMap::~DynamicMMap()
	276	{
2d11135a AL	277	if (Fd == 0)
2d11135a AL	278	{
2a79d5b5	279	if (validData() == false)
26b37f95	280	return;
f1c6a8ca	281	#ifdef _POSIX_MAPPED_FILES
a67de73e	282	munmap(Base, WorkSpace);
f1c6a8ca	283	#else
2d11135a	284	delete [] (unsigned char *)Base;
f1c6a8ca	285	#endif
2d11135a AL	286	return;
	287	}
	288
650faab0	289	unsigned long long EndOfFile = iSize;
1164783d	290	iSize = WorkSpace;
2d11135a	291	Close(false);
3c8cda8b MV	292	if(ftruncate(Fd->Fd(),EndOfFile) < 0)
3c8cda8b MV	293	_error->Errno("ftruncate", _("Failed to truncate file"));
578bfd0a AL	294	}
	295	/}}}/
	296	// DynamicMMap::RawAllocate - Allocate a raw chunk of unaligned space /{{{/
	297	// ---------------------------------------------------------------------
f55a958f	298	/* This allocates a block of memory aligned to the given size */
650faab0	299	unsigned long DynamicMMap::RawAllocate(unsigned long long Size,unsigned long Aln)
578bfd0a	300	{
650faab0	301	unsigned long long Result = iSize;
f55a958f AL	302	if (Aln != 0)
f55a958f AL	303	Result += Aln - (iSize%Aln);
c5f44afc	304
f55a958f	305	iSize = Result + Size;
c5f44afc	306
f1c6a8ca DK	307	// try to grow the buffer
f1c6a8ca DK	308	while(Result + Size > WorkSpace)
578bfd0a	309	{
f1c6a8ca DK	310	if(!Grow())
f1c6a8ca DK	311	{
5afa55c6	312	_error->Fatal(_("Dynamic MMap ran out of room. Please increase the size "
f1c6a8ca DK	313	"of APT::Cache-Limit. Current value: %lu. (man 5 apt.conf)"), WorkSpace);
	314	return 0;
	315	}
578bfd0a	316	}
578bfd0a AL	317	return Result;
	318	}
	319	/}}}/
	320	// DynamicMMap::Allocate - Pooled aligned allocation /{{{/
	321	// ---------------------------------------------------------------------
	322	/* This allocates an Item of size ItemSize so that it is aligned to its
	323	size in the file. */
	324	unsigned long DynamicMMap::Allocate(unsigned long ItemSize)
c5f44afc	325	{
578bfd0a AL	326	// Look for a matching pool entry
	327	Pool *I;
	328	Pool *Empty = 0;
a9fe5928	329	for (I = Pools; I != Pools + PoolCount; ++I)
578bfd0a AL	330	{
	331	if (I->ItemSize == 0)
	332	Empty = I;
	333	if (I->ItemSize == ItemSize)
	334	break;
	335	}
578bfd0a AL	336	// No pool is allocated, use an unallocated one
	337	if (I == Pools + PoolCount)
	338	{
	339	// Woops, we ran out, the calling code should allocate more.
	340	if (Empty == 0)
	341	{
	342	_error->Error("Ran out of allocation pools");
	343	return 0;
	344	}
	345
	346	I = Empty;
	347	I->ItemSize = ItemSize;
	348	I->Count = 0;
	349	}
c5f44afc DK	350
c5f44afc DK	351	unsigned long Result = 0;
578bfd0a AL	352	// Out of space, allocate some more
	353	if (I->Count == 0)
	354	{
c5f44afc DK	355	const unsigned long size = 20*1024;
c5f44afc DK	356	I->Count = size/ItemSize;
a9fe5928	357	Pool* oldPools = Pools;
c5f44afc	358	Result = RawAllocate(size,ItemSize);
a9fe5928 DK	359	if (Pools != oldPools)
	360	I += Pools - oldPools;
	361
c5f44afc DK	362	// Does the allocation failed ?
	363	if (Result == 0 && _error->PendingError())
	364	return 0;
	365	I->Start = Result;
	366	}
	367	else
	368	Result = I->Start;
f55a958f	369
578bfd0a	370	I->Count--;
c5f44afc	371	I->Start += ItemSize;
578bfd0a AL	372	return Result/ItemSize;
	373	}
	374	/}}}/
	375	// DynamicMMap::WriteString - Write a string to the file /{{{/
	376	// ---------------------------------------------------------------------
	377	/* Strings are not aligned to anything */
	378	unsigned long DynamicMMap::WriteString(const char *String,
	379	unsigned long Len)
	380	{
6e52073f	381	if (Len == (unsigned long)-1)
578bfd0a	382	Len = strlen(String);
c5f44afc	383
a9fe5928	384	unsigned long const Result = RawAllocate(Len+1,0);
c5f44afc DK	385
	386	if (Result == 0 && _error->PendingError())
	387	return 0;
	388
578bfd0a AL	389	memcpy((char *)Base + Result,String,Len);
	390	((char *)Base)[Result + Len] = 0;
	391	return Result;
	392	}
	393	/}}}/
f1c6a8ca DK	394	// DynamicMMap::Grow - Grow the mmap /{{{/
f1c6a8ca DK	395	// ---------------------------------------------------------------------
d6c4a976 DK	396	/* This method is a wrapper around different methods to (try to) grow
	397	a mmap (or our char[]-fallback). Encounterable environments:
	398	1. Moveable + !Fallback + linux -> mremap with MREMAP_MAYMOVE
	399	2. Moveable + !Fallback + !linux -> not possible (forbidden by constructor)
	400	3. Moveable + Fallback -> realloc
	401	4. !Moveable + !Fallback + linux -> mremap alone - which will fail in 99,9%
	402	5. !Moveable + !Fallback + !linux -> not possible (forbidden by constructor)
	403	6. !Moveable + Fallback -> not possible
	404	[ While Moveable and Fallback stands for the equally named flags and
	405	"linux" indicates a linux kernel instead of a freebsd kernel. ]
	406	So what you can see here is, that a MMAP which want to be growable need
	407	to be moveable to have a real chance but that this method will at least try
	408	the nearly impossible 4 to grow it before it finally give up: Never say never. */
	409	bool DynamicMMap::Grow() {
	410	if (Limit != 0 && WorkSpace >= Limit)
e3ac3b46 DK	411	return _error->Error(_("Unable to increase the size of the MMap as the "
e3ac3b46 DK	412	"limit of %lu bytes is already reached."), Limit);
dcdf1ef1 DK	413	if (GrowFactor <= 0)
dcdf1ef1 DK	414	return _error->Error(_("Unable to increase size of the MMap as automatic growing is disabled by user."));
f1c6a8ca	415
650faab0	416	unsigned long long const newSize = WorkSpace + GrowFactor;
f1c6a8ca	417
d6c4a976 DK	418	if(Fd != 0) {
	419	Fd->Seek(newSize - 1);
	420	char C = 0;
	421	Fd->Write(&C,sizeof(C));
	422	}
a9fe5928 DK	423
	424	unsigned long const poolOffset = Pools - ((Pool*) Base);
	425
d6c4a976 DK	426	if ((Flags & Fallback) != Fallback) {
	427	#if defined(_POSIX_MAPPED_FILES) && defined(__linux__)
	428	#ifdef MREMAP_MAYMOVE
a9fe5928	429
d6c4a976 DK	430	if ((Flags & Moveable) == Moveable)
	431	Base = mremap(Base, WorkSpace, newSize, MREMAP_MAYMOVE);
	432	else
	433	#endif
	434	Base = mremap(Base, WorkSpace, newSize, 0);
f1c6a8ca	435
d6c4a976 DK	436	if(Base == MAP_FAILED)
d6c4a976 DK	437	return false;
f1c6a8ca	438	#else
d6c4a976	439	return false;
f1c6a8ca	440	#endif
d6c4a976 DK	441	} else {
	442	if ((Flags & Moveable) != Moveable)
	443	return false;
	444
	445	Base = realloc(Base, newSize);
	446	if (Base == NULL)
	447	return false;
	448	}
	449
a9fe5928	450	Pools =(Pool*) Base + poolOffset;
d6c4a976 DK	451	WorkSpace = newSize;
d6c4a976 DK	452	return true;
f1c6a8ca DK	453	}
f1c6a8ca DK	454	/}}}/