X-Git-Url: https://git.saurik.com/apt.git/blobdiff_plain/027010953973bc868262a110e79610880610728d..5f1b8fadbba7108ba20bd07c7479eb5e5704308e:/apt-pkg/pkgcache.cc?ds=sidebyside

diff --git a/apt-pkg/pkgcache.cc b/apt-pkg/pkgcache.cc
index e65e37bca..347a0954e 100644
--- a/apt-pkg/pkgcache.cc
+++ b/apt-pkg/pkgcache.cc
@@ -39,6 +39,7 @@
 #include <vector>
 #include <string>
 #include <sys/stat.h>
+#include <zlib.h>
 
 #include <apti18n.h>
 									/*}}}*/
@@ -57,7 +58,7 @@ pkgCache::Header::Header()
    /* Whenever the structures change the major version should be bumped,
       whenever the generator changes the minor version should be bumped. */
    APT_HEADER_SET(MajorVersion, 10);
-   APT_HEADER_SET(MinorVersion, 2);
+   APT_HEADER_SET(MinorVersion, 3);
    APT_HEADER_SET(Dirty, false);
 
    APT_HEADER_SET(HeaderSz, sizeof(pkgCache::Header));
@@ -93,7 +94,7 @@ pkgCache::Header::Header()
    VerSysName = 0;
    Architecture = 0;
    SetArchitectures(0);
-   SetHashTableSize(_config->FindI("APT::Cache-HashTableSize", 10 * 1048));
+   SetHashTableSize(_config->FindI("APT::Cache-HashTableSize", 15013));
    memset(Pools,0,sizeof(Pools));
 
    CacheFileSize = 0;
@@ -173,9 +174,6 @@ bool pkgCache::ReMap(bool const &Errorchecks)
        HeaderP->CheckSizes(DefHeader) == false)
       return _error->Error(_("The package cache file is an incompatible version"));
 
-   if (Map.Size() < HeaderP->CacheFileSize)
-      return _error->Error(_("The package cache file is corrupted, it is too small"));
-
    if (HeaderP->VerSysName == 0 || HeaderP->Architecture == 0 || HeaderP->GetArchitectures() == 0)
       return _error->Error(_("The package cache file is corrupted"));
 
@@ -193,6 +191,13 @@ bool pkgCache::ReMap(bool const &Errorchecks)
 	 list != StrP + HeaderP->GetArchitectures())
       return _error->Error(_("The package cache was built for different architectures: %s vs %s"), StrP + HeaderP->GetArchitectures(), list.c_str());
 
+
+   auto hash = CacheHash();
+   if (_config->FindB("Debug::pkgCacheGen", false))
+      std::clog << "Opened cache with hash " << hash << ", expecting " <<  HeaderP->CacheFileSize << "\n";
+   if (hash != HeaderP->CacheFileSize)
+      return _error->Error(_("The package cache file is corrupted, it has the wrong hash"));
+
    return true;
 }
 									/*}}}*/
@@ -203,19 +208,44 @@ bool pkgCache::ReMap(bool const &Errorchecks)
    table (480 used items) */
 map_id_t pkgCache::sHash(const string &Str) const
 {
-   unsigned long Hash = 0;
+   uint32_t Hash = 5381;
    for (string::const_iterator I = Str.begin(); I != Str.end(); ++I)
-      Hash = 41 * Hash + tolower_ascii(*I);
+      Hash = 33 * Hash + tolower_ascii(*I);
    return Hash % HeaderP->GetHashTableSize();
 }
 
 map_id_t pkgCache::sHash(const char *Str) const
 {
-   unsigned long Hash = tolower_ascii(*Str);
-   for (const char *I = Str + 1; *I != 0; ++I)
-      Hash = 41 * Hash + tolower_ascii(*I);
+   uint32_t Hash = 5381;
+   for (const char *I = Str; *I != 0; ++I)
+      Hash = 33 * Hash + tolower_ascii(*I);
    return Hash % HeaderP->GetHashTableSize();
 }
+
+uint32_t pkgCache::CacheHash()
+{
+   pkgCache::Header header = {};
+   uLong adler = adler32(0L, Z_NULL, 0);
+
+   if (Map.Size() < sizeof(header))
+      return adler;
+   memcpy(&header, GetMap().Data(), sizeof(header));
+
+   header.Dirty = false;
+   header.CacheFileSize = 0;
+
+   adler = adler32(adler,
+		   reinterpret_cast<const unsigned char *>(&header),
+		   sizeof(header));
+
+   if (Map.Size() > sizeof(header)) {
+      adler = adler32(adler,
+		      static_cast<const unsigned char *>(GetMap().Data()) + sizeof(header),
+		      GetMap().Size() - sizeof(header));
+   }
+
+   return adler;
+}
 									/*}}}*/
 // Cache::FindPkg - Locate a package by name				/*{{{*/
 // ---------------------------------------------------------------------