* contrib/mmap.cc:

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

diff --git a/apt-pkg/contrib/mmap.cc b/apt-pkg/contrib/mmap.cc
index e395e6cc74f5c6741a4220cdbb19935e81d1457a..d233e51bc0cc249c0f5adab10bc445cecbb60233 100644 (file)
--- a/apt-pkg/contrib/mmap.cc
+++ b/apt-pkg/contrib/mmap.cc
@@ -13,18 +13,9 @@
    libc6 generates warnings -- which should be errors, g++ isn't properly
    strict.
    
    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                                                       /*{{{*/
    ##################################################################### */
                                                                        /*}}}*/
 // Include Files                                                       /*{{{*/

-#ifdef __GNUG__
-#pragma implementation "apt-pkg/mmap.h"
-#endif 
-

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


@@ -35,13 +26,17 @@
 #include <sys/stat.h>
 #include <unistd.h>
 #include <fcntl.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),
                                                                        /*}}}*/
 
 // MMap::MMap - Constructor                                            /*{{{*/
 // ---------------------------------------------------------------------
 /* */
 MMap::MMap(FileFd &F,unsigned long Flags) : Flags(Flags), iSize(0),

-                     Base(0)
+                     Base(0), SyncToFd(NULL)

 {
    if ((Flags & NoImmMap) != NoImmMap)
       Map(F);
 {
    if ((Flags & NoImmMap) != NoImmMap)
       Map(F);


@@ -51,7 +46,7 @@ MMap::MMap(FileFd &F,unsigned long Flags) : Flags(Flags), iSize(0),
 // ---------------------------------------------------------------------
 /* */
 MMap::MMap(unsigned long Flags) : Flags(Flags), iSize(0),
 // ---------------------------------------------------------------------
 /* */
 MMap::MMap(unsigned long Flags) : Flags(Flags), iSize(0),

-                     Base(0)
+                     Base(0), SyncToFd(NULL)

 {
 }
                                                                        /*}}}*/
 {
 }
                                                                        /*}}}*/


@@ -84,7 +79,24 @@ bool MMap::Map(FileFd &Fd)
    // Map it.
    Base = mmap(0,iSize,Prot,Map,Fd.Fd(),0);
    if (Base == (void *)-1)
    // Map it.
    Base = mmap(0,iSize,Prot,Map,Fd.Fd(),0);
    if (Base == (void *)-1)

-      return _error->Errno("mmap",_("Couldn't make mmap of %lu bytes"),iSize);
+   {
+      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;
 }
 
    return true;
 }


@@ -99,10 +111,19 @@ bool MMap::Close(bool DoSync)
    
    if (DoSync == true)
       Sync();
    
    if (DoSync == true)
       Sync();

-   
-   if (munmap((char *)Base,iSize) != 0)
-      _error->Warning("Unable to munmap");
-   
+
+   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;
    iSize = 0;
    Base = 0;
    return true;


@@ -119,8 +140,18 @@ bool MMap::Sync()
    
 #ifdef _POSIX_SYNCHRONIZED_IO   
    if ((Flags & ReadOnly) != ReadOnly)
    
 #ifdef _POSIX_SYNCHRONIZED_IO   
    if ((Flags & ReadOnly) != ReadOnly)

-      if (msync((char *)Base,iSize,MS_SYNC) != 0)
-        return _error->Errno("msync","Unable to write mmap");
+   {
+      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;
 }
 #endif   
    return true;
 }


@@ -136,8 +167,19 @@ bool MMap::Sync(unsigned long Start,unsigned long Stop)
 #ifdef _POSIX_SYNCHRONIZED_IO
    unsigned long PSize = sysconf(_SC_PAGESIZE);
    if ((Flags & ReadOnly) != ReadOnly)
 #ifdef _POSIX_SYNCHRONIZED_IO
    unsigned long PSize = sysconf(_SC_PAGESIZE);
    if ((Flags & ReadOnly) != ReadOnly)

-      if (msync((char *)Base+(int)(Start/PSize)*PSize,Stop - Start,MS_SYNC) != 0)
-        return _error->Errno("msync","Unable to write mmap");
+   {
+      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;
 }
 #endif   
    return true;
 }


@@ -146,8 +188,10 @@ bool MMap::Sync(unsigned long Start,unsigned long Stop)
 // DynamicMMap::DynamicMMap - Constructor                              /*{{{*/
 // ---------------------------------------------------------------------
 /* */
 // 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;
 {
    if (_error->PendingError() == true)
       return;


@@ -168,16 +212,51 @@ DynamicMMap::DynamicMMap(FileFd &F,unsigned long Flags,unsigned long WorkSpace)
                                                                        /*}}}*/
 // DynamicMMap::DynamicMMap - Constructor for a non-file backed map    /*{{{*/
 // ---------------------------------------------------------------------
                                                                        /*}}}*/
 // DynamicMMap::DynamicMMap - Constructor for a non-file backed map    /*{{{*/
 // ---------------------------------------------------------------------

-/* This is just a fancy malloc really.. */
-DynamicMMap::DynamicMMap(unsigned long Flags,unsigned long WorkSpace) :
-             MMap(Flags | NoImmMap | UnMapped), Fd(0), WorkSpace(WorkSpace)
+/* 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;
-   
-   Base = new unsigned char[WorkSpace];
-   memset(Base,0,WorkSpace);
-   iSize = 0;
+       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                              /*{{{*/
 }
                                                                        /*}}}*/
 // DynamicMMap::~DynamicMMap - Destructor                              /*{{{*/


@@ -187,14 +266,19 @@ DynamicMMap::~DynamicMMap()
 {
    if (Fd == 0)
    {
 {
    if (Fd == 0)
    {

+#ifdef _POSIX_MAPPED_FILES
+      munmap(Base, WorkSpace);
+#else

       delete [] (unsigned char *)Base;
       delete [] (unsigned char *)Base;

+#endif

       return;
    }
    
    unsigned long EndOfFile = iSize;
    iSize = WorkSpace;
    Close(false);
       return;
    }
    
    unsigned long EndOfFile = iSize;
    iSize = WorkSpace;
    Close(false);

-   ftruncate(Fd->Fd(),EndOfFile);
+   if(ftruncate(Fd->Fd(),EndOfFile) < 0)
+      _error->Errno("ftruncate", _("Failed to truncate file"));

 }  
                                                                        /*}}}*/
 // DynamicMMap::RawAllocate - Allocate a raw chunk of unaligned space  /*{{{*/
 }  
                                                                        /*}}}*/
 // DynamicMMap::RawAllocate - Allocate a raw chunk of unaligned space  /*{{{*/


@@ -205,16 +289,19 @@ unsigned long DynamicMMap::RawAllocate(unsigned long Size,unsigned long Aln)
    unsigned long Result = iSize;
    if (Aln != 0)
       Result += Aln - (iSize%Aln);
    unsigned long Result = iSize;
    if (Aln != 0)
       Result += Aln - (iSize%Aln);

-   
+

    iSize = Result + Size;
    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");
-      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;
 }
                                                                        /*}}}*/
    return Result;
 }
                                                                        /*}}}*/


@@ -223,7 +310,7 @@ unsigned long DynamicMMap::RawAllocate(unsigned long Size,unsigned long Aln)
 /* 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)
 /* 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;
    // Look for a matching pool entry
    Pool *I;
    Pool *Empty = 0;


@@ -234,7 +321,6 @@ unsigned long DynamicMMap::Allocate(unsigned long ItemSize)
       if (I->ItemSize == ItemSize)
         break;
    }
       if (I->ItemSize == ItemSize)
         break;
    }

-

    // No pool is allocated, use an unallocated one
    if (I == Pools + PoolCount)
    {
    // No pool is allocated, use an unallocated one
    if (I == Pools + PoolCount)
    {


@@ -249,17 +335,24 @@ unsigned long DynamicMMap::Allocate(unsigned long ItemSize)
       I->ItemSize = ItemSize;
       I->Count = 0;
    }
       I->ItemSize = ItemSize;
       I->Count = 0;
    }

-   
+
+   unsigned long Result = 0;

    // Out of space, allocate some more
    if (I->Count == 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--;
 
    I->Count--;

-   unsigned long Result = I->Start;
-   I->Start += ItemSize;  
+   I->Start += ItemSize;

    return Result/ItemSize;
 }
                                                                        /*}}}*/
    return Result/ItemSize;
 }
                                                                        /*}}}*/


@@ -269,19 +362,70 @@ unsigned long DynamicMMap::Allocate(unsigned long ItemSize)
 unsigned long DynamicMMap::WriteString(const char *String,
                                       unsigned long Len)
 {
 unsigned long DynamicMMap::WriteString(const char *String,
                                       unsigned long Len)
 {

-   unsigned long Result = iSize;
-   // Just in case error check
-   if (Result + Len > WorkSpace)
-   {
-      _error->Error("Dynamic MMap ran out of room");
-      return 0;
-   }   
-   

    if (Len == (unsigned long)-1)
       Len = strlen(String);
    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;
 }
                                                                        /*}}}*/
    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;
+}
+                                                                       /*}}}*/