diff options
Diffstat (limited to 'apt-pkg/contrib/mmap.cc')
| -rw-r--r-- | apt-pkg/contrib/mmap.cc | 108 |
1 files changed, 87 insertions, 21 deletions
diff --git a/apt-pkg/contrib/mmap.cc b/apt-pkg/contrib/mmap.cc index 04a45811b..5f56178f4 100644 --- a/apt-pkg/contrib/mmap.cc +++ b/apt-pkg/contrib/mmap.cc @@ -13,17 +13,13 @@ 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 <apt-pkg/mmap.h> #include <apt-pkg/error.h> +#include <apt-pkg/configuration.h> #include <apti18n.h> @@ -31,6 +27,8 @@ #include <sys/stat.h> #include <unistd.h> #include <fcntl.h> +#include <stdlib.h> +#include <signal.h> #include <cstring> /*}}}*/ @@ -141,6 +139,20 @@ bool MMap::Sync(unsigned long Start,unsigned long Stop) } /*}}}*/ +// 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 /*{{{*/ // --------------------------------------------------------------------- /* */ @@ -166,13 +178,30 @@ DynamicMMap::DynamicMMap(FileFd &F,unsigned long Flags,unsigned long WorkSpace) /*}}}*/ // DynamicMMap::DynamicMMap - Constructor for a non-file backed map /*{{{*/ // --------------------------------------------------------------------- -/* This is just a fancy malloc really.. */ +/* 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) { if (_error->PendingError() == true) return; - + + if (_config->FindB("MMap::SegfaultHandler",true) == true) + { + struct sigaction sa; + sa.sa_handler = DynamicMMapSegfaultHandler; + sigaction(SIGSEGV, &sa, NULL); + } + +#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; +#endif + // fallback to a static allocated space Base = new unsigned char[WorkSpace]; memset(Base,0,WorkSpace); iSize = 0; @@ -185,7 +214,11 @@ DynamicMMap::~DynamicMMap() { if (Fd == 0) { +#ifdef _POSIX_MAPPED_FILES + munmap(Base, WorkSpace); +#else delete [] (unsigned char *)Base; +#endif return; } @@ -207,14 +240,16 @@ unsigned long DynamicMMap::RawAllocate(unsigned long Size,unsigned long Aln) iSize = Result + Size; - // Just in case error check - if (Result + Size > WorkSpace) + // try to grow the buffer + while(Result + Size > WorkSpace) { - _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(!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; } /*}}}*/ @@ -234,7 +269,6 @@ unsigned long DynamicMMap::Allocate(unsigned long ItemSize) if (I->ItemSize == ItemSize) break; } - // No pool is allocated, use an unallocated one if (I == Pools + PoolCount) { @@ -270,14 +304,17 @@ unsigned long DynamicMMap::WriteString(const char *String, unsigned long Len) { unsigned long Result = iSize; - // Just in case error check - if (Result + Len > WorkSpace) + // try to grow the buffer + while(Result + Len > WorkSpace) { - _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(!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; @@ -286,3 +323,32 @@ unsigned long DynamicMMap::WriteString(const char *String, 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; + + if(Fd != 0) + { + Fd->Seek(newSize - 1); + char C = 0; + Fd->Write(&C,sizeof(C)); + } + + Base = mremap(Base, WorkSpace, newSize, 0); + if(Base == MAP_FAILED) + return false; + + WorkSpace = newSize; + return true; +#else + return false; +#endif +} + /*}}}*/ |