#define _BSD_SOURCE
#include <apt-pkg/mmap.h>
#include <apt-pkg/error.h>
-#include <apt-pkg/configuration.h>
#include <apti18n.h>
#include <unistd.h>
#include <fcntl.h>
#include <stdlib.h>
-#include <signal.h>
#include <cstring>
/*}}}*/
}
/*}}}*/
-// DynamicMMapSegfaultHandler /*{{{*/
-// ---------------------------------------------------------------------
-/* In theory, the mmap should never segfault because we check the available
- size of our mmap before we use it, but there are a few reports out there
- which state that the mmap segfaults without further notice. So this handler
- will take care of all these segfaults which should never happen... */
-void DynamicMMapSegfaultHandler(int)
-{
- _error->Error(_("Dynamic MMap segfaults, most likely because it ran out of room. "
- "Please increase the size of APT::Cache-Limit. (man 5 apt.conf)"));
- _error->DumpErrors();
- exit(EXIT_FAILURE);
-}
- /*}}}*/
// DynamicMMap::DynamicMMap - Constructor /*{{{*/
// ---------------------------------------------------------------------
/* */
-DynamicMMap::DynamicMMap(FileFd &F,unsigned long Flags,unsigned long WorkSpace) :
- MMap(F,Flags | NoImmMap), Fd(&F), WorkSpace(WorkSpace)
+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;
/* 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 WorkSpace) :
- MMap(Flags | NoImmMap | UnMapped), Fd(0), WorkSpace(WorkSpace)
+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;
+ if (_error->PendingError() == true)
+ return;
- if (_config->FindB("MMap::SegfaultHandler",true) == true)
- {
- struct sigaction sa;
- sa.sa_handler = DynamicMMapSegfaultHandler;
- sigaction(SIGSEGV, &sa, NULL);
- }
+ // 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
- // use anonymous mmap() to get the memory
- Base = (unsigned char*) mmap(0, WorkSpace, PROT_READ|PROT_WRITE,
- MAP_ANONYMOUS|MAP_PRIVATE, -1, 0);
- if(Base != MAP_FAILED)
- return;
+ 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;
+ // fallback to a static allocated space
+ Base = new unsigned char[WorkSpace];
+ memset(Base,0,WorkSpace);
+ iSize = 0;
}
/*}}}*/
// DynamicMMap::~DynamicMMap - Destructor /*{{{*/
unsigned long Result = iSize;
if (Aln != 0)
Result += Aln - (iSize%Aln);
-
+
iSize = Result + Size;
-
+
// try to grow the buffer
while(Result + Size > WorkSpace)
{
/* 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;
I->ItemSize = ItemSize;
I->Count = 0;
}
-
+
+ unsigned long Result = 0;
// Out of space, allocate some more
if (I->Count == 0)
{
- I->Count = 20*1024/ItemSize;
- I->Start = RawAllocate(I->Count*ItemSize,ItemSize);
- }
+ 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--;
- unsigned long Result = I->Start;
- I->Start += ItemSize;
+ I->Start += ItemSize;
return Result/ItemSize;
}
/*}}}*/
unsigned long DynamicMMap::WriteString(const char *String,
unsigned long Len)
{
- unsigned long Result = iSize;
- // try to grow the buffer
- while(Result + Len > 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;
- }
- }
-
if (Len == (unsigned long)-1)
Len = strlen(String);
- iSize += Len + 1;
+
+ 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 will try to grow the mmap we currently use. This doesn't
- work most of the time because we can't move the mmap around in the
- memory for now as this would require to adjust quite a lot of pointers
- but why we should not at least try to grow it before we give up? */
-bool DynamicMMap::Grow()
-{
-#ifdef _POSIX_MAPPED_FILES
- unsigned long newSize = WorkSpace + 1024*1024;
+/* 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(_("The size of a MMap has already reached the defined limit of %lu bytes,"
+ "abort the try to grow the MMap."), Limit);
- if(Fd != 0)
- {
- Fd->Seek(newSize - 1);
- char C = 0;
- Fd->Write(&C,sizeof(C));
- }
+ unsigned long const newSize = WorkSpace + 1024*1024;
- Base = mremap(Base, WorkSpace, newSize, 0);
- if(Base == MAP_FAILED)
- return false;
+ 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);
- WorkSpace = newSize;
- return true;
+ if(Base == MAP_FAILED)
+ return false;
#else
- return false;
+ return false;
#endif
+ } else {
+ if ((Flags & Moveable) != Moveable)
+ return false;
+
+ Base = realloc(Base, newSize);
+ if (Base == NULL)
+ return false;
+ }
+
+ WorkSpace = newSize;
+ return true;
}
/*}}}*/
projects / apt.git / blobdiff