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Diffstat (limited to 'apt-pkg/contrib/mmap.cc')
| -rw-r--r-- | apt-pkg/contrib/mmap.cc | 227 |
1 files changed, 227 insertions, 0 deletions
diff --git a/apt-pkg/contrib/mmap.cc b/apt-pkg/contrib/mmap.cc new file mode 100644 index 000000000..85cac1cca --- /dev/null +++ b/apt-pkg/contrib/mmap.cc @@ -0,0 +1,227 @@ +// -*- mode: cpp; mode: fold -*- +// Description /*{{{*/ +// $Id: mmap.cc,v 1.1 1998/07/02 02:58:13 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. + + The configure test notes that some OS's have broken private mmap's + so on those OS's we can't use mmap. This means we have to use + configure to test mmap and can't rely on the POSIX + _POSIX_MAPPED_FILES test. + + ##################################################################### */ + /*}}}*/ +// Include Files /*{{{*/ +#define _BSD_SOURCE +#include <pkglib/mmap.h> +#include <pkglib/error.h> + +#include <sys/mman.h> +#include <sys/stat.h> +#include <sys/user.h> +#include <unistd.h> +#include <fcntl.h> + /*}}}*/ + +// MMap::MMap - Constructor /*{{{*/ +// --------------------------------------------------------------------- +/* */ +MMap::MMap(File &F,unsigned long Flags) : Fd(F), Flags(Flags), iSize(0), + Base(0) +{ + if ((Flags & NoImmMap) != NoImmMap) + Map(); +} + /*}}}*/ +// MMap::~MMap - Destructor /*{{{*/ +// --------------------------------------------------------------------- +/* */ +MMap::~MMap() +{ + Close(true); +} + /*}}}*/ +// MMap::Map - Perform the mapping /*{{{*/ +// --------------------------------------------------------------------- +/* */ +bool MMap::Map() +{ + 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; + + // Map it. + Base = mmap(0,iSize,Prot,Map,Fd.Fd(),0); + if (Base == (void *)-1) + return _error->Errno("mmap","Couldn't make mmap of %u bytes",iSize); + + return true; +} + /*}}}*/ +// MMap::Close - Close the map /*{{{*/ +// --------------------------------------------------------------------- +/* */ +bool MMap::Close(bool DoClose) +{ + if (Fd.IsOpen() == false) + return true; + + Sync(); + + if (munmap((char *)Base,iSize) != 0) + _error->Warning("Unable to munmap"); + + iSize = 0; + if (DoClose == true) + Fd.Close(); + return true; +} + /*}}}*/ +// MMap::Sync - Syncronize the map with the disk /*{{{*/ +// --------------------------------------------------------------------- +/* */ +bool MMap::Sync() +{ + if ((Flags & ReadOnly) == ReadOnly) + if (msync((char *)Base,iSize,MS_SYNC) != 0) + return _error->Error("msync","Unable to write mmap"); + return true; +} + /*}}}*/ +// MMap::Sync - Syncronize a section of the file to disk /*{{{*/ +// --------------------------------------------------------------------- +/* */ +bool MMap::Sync(unsigned long Start,unsigned long Stop) +{ + if ((Flags & ReadOnly) == ReadOnly) + if (msync((char *)Base+(int)(Start/PAGE_SIZE)*PAGE_SIZE,Stop - Start,MS_SYNC) != 0) + return _error->Error("msync","Unable to write mmap"); + return true; +} + /*}}}*/ + +// DynamicMMap::DynamicMMap - Constructor /*{{{*/ +// --------------------------------------------------------------------- +/* */ +DynamicMMap::DynamicMMap(File &F,unsigned long Flags,unsigned long WorkSpace) : + MMap(F,Flags | NoImmMap), WorkSpace(WorkSpace) +{ + unsigned long EndOfFile = Fd.Size(); + Fd.Seek(WorkSpace); + char C = 0; + Fd.Write(&C,sizeof(C)); + Map(); + iSize = EndOfFile; +} + /*}}}*/ +// DynamicMMap::~DynamicMMap - Destructor /*{{{*/ +// --------------------------------------------------------------------- +/* We truncate the file to the size of the memory data set */ +DynamicMMap::~DynamicMMap() +{ + unsigned long EndOfFile = iSize; + Close(false); + ftruncate(Fd.Fd(),EndOfFile); + Fd.Close(); +} + /*}}}*/ +// DynamicMMap::RawAllocate - Allocate a raw chunk of unaligned space /*{{{*/ +// --------------------------------------------------------------------- +/* */ +unsigned long DynamicMMap::RawAllocate(unsigned long Size) +{ + unsigned long Result = iSize; + iSize += Size; + + // Just in case error check + if (Result > WorkSpace) + { + _error->Error("Dynamic MMap ran out of room"); + 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; + } + + // Out of space, allocate some more + if (I->Count == 0) + { + I->Count = 20*1024/ItemSize; + I->Start = RawAllocate(I->Count*ItemSize); + } + + I->Count--; + unsigned long Result = I->Start; + 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) +{ + unsigned long Result = iSize; + // Just in case error check + if (Result > WorkSpace) + { + _error->Error("Dynamic MMap ran out of room"); + return 0; + } + + if (Len == 0) + Len = strlen(String); + iSize += Len + 1; + memcpy((char *)Base + Result,String,Len); + ((char *)Base)[Result + Len] = 0; + return Result; +} + /*}}}*/ |