Join with aliencode

Author: jgg
Date: 2001-02-20 07:03:16 GMT
Join with aliencode

1 files changed, 509 insertions, 0 deletions

diff --git a/apt-inst/extract.cc b/apt-inst/extract.cc
new file mode 100644
index 000000000..a3c06c088
--- /dev/null
+++ b/apt-inst/extract.cc
@@ -0,0 +1,509 @@
+// -*- mode: cpp; mode: fold -*-
+// Description								/*{{{*/
+// $Id: extract.cc,v 1.2 2001/02/20 07:03:16 jgg Exp $
+/* ######################################################################
+
+   Archive Extraction Directory Stream
+   
+   Extraction for each file is a bit of an involved process. Each object
+   undergoes an atomic backup, overwrite, erase sequence. First the
+   object is unpacked to '.dpkg.new' then the original is hardlinked to
+   '.dpkg.tmp' and finally the new object is renamed to overwrite the old
+   one. From an external perspective the file never ceased to exist.
+   After the archive has been sucessfully unpacked the .dpkg.tmp files 
+   are erased. A failure causes all the .dpkg.tmp files to be restored.
+   
+   Decisions about unpacking go like this:
+      - Store the original filename in the file listing
+      - Resolve any diversions that would effect this file, all checks
+        below apply to the diverted name, not the real one.
+      - Resolve any symlinked configuration files.
+      - If the existing file does not exist then .dpkg-tmp is checked for.
+        [Note, this is reduced to only check if a file was expected to be
+         there]
+      - If the existing link/file is not a directory then it is replaced
+        irregardless
+      - If the existing link/directory is being replaced by a directory then
+        absolutely nothing happens.
+      - If the existing link/directory is being replaced by a link then
+        absolutely nothing happens.
+      - If the existing link/directory is being replaced by a non-directory
+        then this will abort if the package is not the sole owner of the
+        directory. [Note, this is changed to not happen if the directory
+        non-empty - that is, it only includes files that are part of this
+        package - prevents removing user files accidentally.]
+      - If the non-directory exists in the listing database and it
+        does not belong to the current package then an overwrite condition
+        is invoked. 
+   
+   As we unpack we record the file list differences in the FL cache. If
+   we need to unroll the the FL cache knows which files have been unpacked
+   and can undo. When we need to erase then it knows which files have not 
+   been unpacked.
+   
+   ##################################################################### */
+									/*}}}*/
+// Include Files							/*{{{*/
+#ifdef __GNUG__
+#pragma implementation "apt-pkg/extract.h"
+#endif
+#include <apt-pkg/extract.h>
+#include <apt-pkg/error.h>
+#include <apt-pkg/debversion.h>
+
+#include <sys/stat.h>
+#include <stdio.h>
+#include <unistd.h>
+#include <errno.h>
+#include <dirent.h>
+									/*}}}*/
+
+static const char *TempExt = "dpkg-tmp";
+//static const char *NewExt = "dpkg-new";
+
+// Extract::pkgExtract - Constructor					/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+pkgExtract::pkgExtract(pkgFLCache &FLCache,pkgCache::VerIterator Ver) : 
+                       FLCache(FLCache), Ver(Ver)
+{
+   FLPkg = FLCache.GetPkg(Ver.ParentPkg().Name(),true);
+   if (FLPkg.end() == true)
+      return;
+   Debug = true;
+}
+									/*}}}*/
+// Extract::DoItem - Handle a single item from the stream		/*{{{*/
+// ---------------------------------------------------------------------
+/* This performs the setup for the extraction.. */
+bool pkgExtract::DoItem(Item &Itm,int &Fd)
+{
+   char Temp[sizeof(FileName)];
+   
+   /* Strip any leading/trailing /s from the filename, then copy it to the
+      temp buffer and re-apply the leading / We use a class variable
+      to store the new filename for use by the three extraction funcs */
+   char *End = FileName+1;
+   const char *I = Itm.Name;
+   for (; *I != 0 && *I == '/'; I++);
+   *FileName = '/';
+   for (; *I != 0 && End < FileName + sizeof(FileName); I++, End++)
+      *End = *I;
+   if (End + 20 >= FileName + sizeof(FileName))
+      return _error->Error("The path %s is too long",Itm.Name);   
+   for (; End > FileName && End[-1] == '/'; End--);
+   *End = 0;
+   Itm.Name = FileName;
+   
+   /* Lookup the file. Nde is the file [group] we are going to write to and
+      RealNde is the actual node we are manipulating. Due to diversions
+      they may be entirely different. */
+   pkgFLCache::NodeIterator Nde = FLCache.GetNode(Itm.Name,End,0,false,false);
+   pkgFLCache::NodeIterator RealNde = Nde;
+      
+   // See if the file is already in the file listing
+   unsigned long FileGroup = RealNde->File;
+   for (; RealNde.end() == false && FileGroup == RealNde->File; RealNde++)
+      if (RealNde.RealPackage() == FLPkg)
+	 break;
+
+   // Nope, create an entry
+   if (RealNde.end() == true)
+   {
+      RealNde = FLCache.GetNode(Itm.Name,End,FLPkg.Offset(),true,false);
+      if (RealNde.end() == true)
+	 return false;
+      RealNde->Flags |= pkgFLCache::Node::NewFile;
+   }
+
+   /* Check if this entry already was unpacked. The only time this should 
+      ever happen is if someone has hacked tar to support capabilities, in
+      which case this needs to be modified anyhow.. */
+   if ((RealNde->Flags & pkgFLCache::Node::Unpacked) ==
+       pkgFLCache::Node::Unpacked)
+      return _error->Error("Unpacking %s more than once",Itm.Name);
+   
+   if (Nde.end() == true)
+      Nde = RealNde;
+
+   /* Consider a diverted file - We are not permitted to divert directories,
+      but everything else is fair game (including conf files!) */
+   if ((Nde->Flags & pkgFLCache::Node::Diversion) != 0)
+   {
+      if (Itm.Type == Item::Directory)
+	 return _error->Error("The directory %s is diverted",Itm.Name);
+
+      /* A package overwriting a diversion target is just the same as 
+         overwriting a normally owned file and is checked for below in
+	 the overwrites mechanism */
+
+      /* If this package is trying to overwrite the target of a diversion, 
+         that is never, ever permitted */
+      pkgFLCache::DiverIterator Div = Nde.Diversion();
+      if (Div.DivertTo() == Nde)
+	 return _error->Error("The package is trying to write to the "
+			      "diversion target %s/%s",Nde.DirN(),Nde.File());
+      
+      // See if it is us and we are following it in the right direction
+      if (Div->OwnerPkg != FLPkg.Offset() && Div.DivertFrom() == Nde)
+      {
+	 Nde = Div.DivertTo();
+	 End = FileName + snprintf(FileName,sizeof(FileName)-20,"%s/%s",
+				   Nde.DirN(),Nde.File());
+	 if (End <= FileName)
+	    return _error->Error("The diversion path is too long");
+      }      
+   }
+   
+   // Deal with symlinks and conf files
+   if ((RealNde->Flags & pkgFLCache::Node::NewConfFile) == 
+       pkgFLCache::Node::NewConfFile)
+   {
+      string Res = flNoLink(Itm.Name);
+      if (Res.length() > sizeof(FileName))
+	 return _error->Error("The path %s is too long",Res.c_str());
+      if (Debug == true)
+	 clog << "Followed conf file from " << FileName << " to " << Res << endl;
+      Itm.Name = strcpy(FileName,Res.c_str());      
+   }
+   
+   /* Get information about the existing file, and attempt to restore
+      a backup if it does not exist */
+   struct stat LExisting;
+   bool EValid = false;
+   if (lstat(Itm.Name,&LExisting) != 0)
+   {
+      // This is bad news.
+      if (errno != ENOENT)
+	 return _error->Errno("stat","Failed to stat %s",Itm.Name);
+      
+      // See if we can recover the backup file
+      if (Nde.end() == false)
+      {
+	 snprintf(Temp,sizeof(Temp),"%s.%s",Itm.Name,TempExt);
+	 if (rename(Temp,Itm.Name) != 0 && errno != ENOENT)
+	    return _error->Errno("rename","Failed to rename %s to %s",
+				 Temp,Itm.Name);
+	 if (stat(Itm.Name,&LExisting) != 0)
+	 {
+	    if (errno != ENOENT)
+	       return _error->Errno("stat","Failed to stat %s",Itm.Name);
+	 }	 
+	 else
+	    EValid = true;
+      }
+   }
+   else
+      EValid = true;
+   
+   /* If the file is a link we need to stat its destination, get the
+      existing file modes */
+   struct stat Existing = LExisting;
+   if (EValid == true && S_ISLNK(Existing.st_mode))
+   {
+      if (stat(Itm.Name,&Existing) != 0)
+      {
+	 if (errno != ENOENT)
+	    return _error->Errno("stat","Failed to stat %s",Itm.Name);
+	 Existing = LExisting;
+      }      
+   }
+   
+   // We pretend a non-existing file looks like it is a normal file
+   if (EValid == false)
+      Existing.st_mode = S_IFREG;
+   
+   /* Okay, at this point 'Existing' is the stat information for the
+      real non-link file */
+   
+   /* The only way this can be a no-op is if a directory is being
+      replaced by a directory or by a link */
+   if (S_ISDIR(Existing.st_mode) != 0 && 
+       (Itm.Type == Item::Directory || Itm.Type == Item::SymbolicLink))
+      return true;
+      
+   /* Non-Directory being replaced by non-directory. We check for over
+      writes here. */
+   if (Nde.end() == false)
+   {
+      if (HandleOverwrites(Nde) == false)
+	 return false;
+   }
+   
+   /* Directory being replaced by a non-directory - this needs to see if
+      the package is the owner and then see if the directory would be
+      empty after the package is removed [ie no user files will be 
+      erased] */
+   if (S_ISDIR(Existing.st_mode) != 0)
+   {
+      if (CheckDirReplace(Itm.Name) == false)
+	 return _error->Error("The directory %s is being replaced by a non-directory",Itm.Name);
+   }
+   
+   if (Debug == true)
+      clog << "Extract " << string(Itm.Name,End) << endl;
+/*   if (Count != 0)
+      return _error->Error("Done");*/
+   
+   return true;
+}
+									/*}}}*/
+// Extract::Finished - Sequence finished, erase the temp files		/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+bool pkgExtract::Finished()
+{
+   return true;
+}
+									/*}}}*/
+// Extract::Aborted - Sequence aborted, undo all our unpacking		/*{{{*/
+// ---------------------------------------------------------------------
+/* This undoes everything that was done by all calls to the DoItem method
+   and restores the File Listing cache to its original form. It bases its
+   actions on the flags value for each node in the cache. */
+bool pkgExtract::Aborted()
+{
+   if (Debug == true)
+      clog << "Aborted, backing out" << endl;
+   
+   pkgFLCache::NodeIterator Files = FLPkg.Files();
+   map_ptrloc *Last = &FLPkg->Files;
+   
+   /* Loop over all files, restore those that have been unpacked from their
+      dpkg-tmp entires */
+   while (Files.end() == false)
+   {
+      // Locate the hash bucket for the node and locate its group head
+      pkgFLCache::NodeIterator Nde(FLCache,FLCache.HashNode(Files));
+      for (; Nde.end() == false && Files->File != Nde->File; Nde++);
+      if (Nde.end() == true)
+	 return _error->Error("Failed to locate node in its hash bucket");
+      
+      if (snprintf(FileName,sizeof(FileName)-20,"%s/%s",
+		   Nde.DirN(),Nde.File()) <= 0)
+	 return _error->Error("The path is too long");
+      
+      // Deal with diversions
+      if ((Nde->Flags & pkgFLCache::Node::Diversion) != 0)
+      {
+	 pkgFLCache::DiverIterator Div = Nde.Diversion();
+	 
+	 // See if it is us and we are following it in the right direction
+	 if (Div->OwnerPkg != FLPkg.Offset() && Div.DivertFrom() == Nde)
+	 {
+	    Nde = Div.DivertTo();
+	    if (snprintf(FileName,sizeof(FileName)-20,"%s/%s",
+			 Nde.DirN(),Nde.File()) <= 0)
+	       return _error->Error("The diversion path is too long");
+	 }
+      }      
+      
+      // Deal with overwrites+replaces
+      for (; Nde.end() == false && Files->File == Nde->File; Nde++)
+      {
+	 if ((Nde->Flags & pkgFLCache::Node::Replaced) == 
+	     pkgFLCache::Node::Replaced)
+	 {
+	    if (Debug == true)
+	       clog << "De-replaced " << FileName << " from " << Nde.RealPackage()->Name << endl;
+	    Nde->Flags &= ~pkgFLCache::Node::Replaced;
+	 }	 
+      }      
+      
+      // Undo the change in the filesystem
+      if (Debug == true)
+	 clog << "Backing out " << FileName;
+      
+      // Remove a new node
+      if ((Files->Flags & pkgFLCache::Node::NewFile) ==
+	 pkgFLCache::Node::NewFile)
+      {
+	 if (Debug == true)
+	    clog << " [new node]" << endl;
+	 pkgFLCache::Node *Tmp = Files;
+	 Files++;
+	 *Last = Tmp->NextPkg;
+	 Tmp->NextPkg = 0;
+
+	 FLCache.DropNode(Tmp - FLCache.NodeP);
+      }
+      else
+      {
+	 if (Debug == true)
+	    clog << endl;
+	 
+	 Last = &Files->NextPkg;
+	 Files++;
+      }      	 
+   }
+   
+   return true;
+}
+									/*}}}*/
+// Extract::Fail - Extraction of a file Failed				/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+bool pkgExtract::Fail(Item &Itm,int Fd)
+{
+   return pkgDirStream::Fail(Itm,Fd);
+}
+									/*}}}*/
+// Extract::FinishedFile - Finished a file				/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+bool pkgExtract::FinishedFile(Item &Itm,int Fd)
+{
+   return pkgDirStream::FinishedFile(Itm,Fd);
+}
+									/*}}}*/
+// Extract::HandleOverwrites - See if a replaces covers this overwrite	/*{{{*/
+// ---------------------------------------------------------------------
+/* Check if the file is in a package that is being replaced by this 
+   package or if the file is being overwritten. Note that if the file
+   is really a directory but it has been erased from the filesystem 
+   this will fail with an overwrite message. This is a limitation of the
+   dpkg file information format. 
+ 
+   XX If a new package installs and another package replaces files in this
+   package what should we do? */
+bool pkgExtract::HandleOverwrites(pkgFLCache::NodeIterator Nde,
+				  bool DiverCheck)
+{
+   pkgFLCache::NodeIterator TmpNde = Nde;
+   unsigned long DiverOwner = 0;
+   unsigned long FileGroup = Nde->File;
+   const char *FirstOwner = 0;
+   for (; Nde.end() == false && FileGroup == Nde->File; Nde++)
+   {
+      if ((Nde->Flags & pkgFLCache::Node::Diversion) != 0)
+      {
+	 /* Store the diversion owner if this is the forward direction
+	    of the diversion */
+	 if (DiverCheck == true)
+	    DiverOwner = Nde.Diversion()->OwnerPkg;
+	 continue;
+      }
+
+      pkgFLCache::PkgIterator FPkg(FLCache,Nde.RealPackage());	 
+      if (FPkg.end() == true || FPkg == FLPkg)
+	 continue;
+      
+      /* This tests trips when we are checking a diversion to see
+         if something has already been diverted by this diversion */
+      if (FPkg.Offset() == DiverOwner)
+	 continue;
+      FirstOwner = FPkg.Name();
+      
+      // Now see if this package matches one in a replace depends
+      pkgCache::DepIterator Dep = Ver.DependsList();
+      bool Ok = false;
+      for (; Dep.end() == false; Dep++)
+      {
+	 if (Dep->Type != pkgCache::Dep::Replaces)
+	    continue;
+	 
+	 // Does the replaces apply to this package?
+	 if (strcmp(Dep.TargetPkg().Name(),FPkg.Name()) != 0)
+	     continue;
+	 
+	 /* Check the version for match. I do not think CurrentVer can be
+	    0 if we are here.. */
+	 pkgCache::PkgIterator Pkg = Dep.TargetPkg();
+	 if (Pkg->CurrentVer == 0)
+	 {
+	    _error->Warning("Overwrite package match with no version for %s",Pkg.Name());
+	    continue;
+	 }
+
+	 // Replaces is met
+	 if (debVS.CheckDep(Pkg.CurrentVer().VerStr(),Dep->CompareOp,Dep.TargetVer()) == true)
+	 {
+	    if (Debug == true)
+	       clog << "Replaced file " << Nde.DirN() << '/' << Nde.File() << " from " << Pkg.Name() << endl;
+	    Nde->Flags |= pkgFLCache::Node::Replaced;
+	    Ok = true;
+	    break;
+	 }
+      }
+      
+      // Negative Hit
+      if (Ok == false)
+	 return _error->Error("File %s/%s overwrites the one in the package %s",
+			      Nde.DirN(),Nde.File(),FPkg.Name());
+   }
+   
+   /* If this is a diversion we might have to recurse to process
+      the other side of it */
+   if ((TmpNde->Flags & pkgFLCache::Node::Diversion) != 0)
+   {
+      pkgFLCache::DiverIterator Div = TmpNde.Diversion();
+      if (Div.DivertTo() == TmpNde)
+	 return HandleOverwrites(Div.DivertFrom(),true);
+   }
+   
+   return true;
+}
+									/*}}}*/
+// Extract::CheckDirReplace - See if this directory can be erased	/*{{{*/
+// ---------------------------------------------------------------------
+/* If this directory is owned by a single package and that package is
+   replacing it with something non-directoryish then dpkg allows this.
+   We increase the requirement to be that the directory is non-empty after
+   the package is removed */
+bool pkgExtract::CheckDirReplace(string Dir,unsigned int Depth)
+{
+   // Looping?
+   if (Depth > 40)
+      return false;
+   
+   if (Dir[Dir.size() - 1] != '/')
+      Dir += '/';
+   
+   DIR *D = opendir(Dir.c_str());
+   if (D == 0)
+      return _error->Errno("opendir","Unable to read %s",Dir.c_str());
+
+   string File;
+   for (struct dirent *Dent = readdir(D); Dent != 0; Dent = readdir(D))
+   {
+      // Skip some files
+      if (strcmp(Dent->d_name,".") == 0 ||
+	  strcmp(Dent->d_name,"..") == 0)
+	 continue;
+      
+      // Look up the node
+      File = Dir + Dent->d_name;
+      pkgFLCache::NodeIterator Nde = FLCache.GetNode(File.begin(),
+						     File.end(),0,false,false);
+
+      // The file is not owned by this package
+      if (Nde.end() != false || Nde.RealPackage() != FLPkg)
+      {
+	 closedir(D);
+	 return false;
+      }
+      
+      // See if it is a directory
+      struct stat St;
+      if (lstat(File.c_str(),&St) != 0)
+      {
+	 closedir(D);
+	 return _error->Errno("lstat","Unable to stat %s",File.c_str());
+      }
+      
+      // Recurse down directories
+      if (S_ISDIR(St.st_mode) != 0)
+      {
+	 if (CheckDirReplace(File,Depth + 1) == false)
+	 {
+	    closedir(D);
+	    return false;
+	 }
+      }      
+   }
+   
+   // No conflicts
+   closedir(D);
+   return true;
+}
+									/*}}}*/