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authorJulian Andres Klode <jak@debian.org>2016-01-23 13:15:31 +0100
committerJulian Andres Klode <jak@debian.org>2016-01-23 15:20:52 +0100
commit7dd0c2eb45874d3df9a9ee2034501659548a1b97 (patch)
tree1c431a2f46c51492d216fa1f8e3e9b17c1466d6a
parent19819ac58a420275e0ae9aa7e2a34c72cba8af5e (diff)
Remap StringView instances pointing into the cache
It turns out that StringViews might need to be remapped in some places because they come from the cache. For example, some sites pass a Ver.VerStr() to NewProvides(). Such a StringView would become invalid during the duration of the call if the cache is remapped, causing the program to die with a segmentation fault. We can take care of those issues by remapping string views in the same way we remap all the iterators. String views are only remapped if they point into the cache though, this allows us to write more generic code on the callee site without having to check whether the view points into the cache or not. That's not as efficient as possible, but the overhead does not appear to be measurable. Closes: #812251
-rw-r--r--apt-pkg/pkgcachegen.cc19
1 files changed, 19 insertions, 0 deletions
diff --git a/apt-pkg/pkgcachegen.cc b/apt-pkg/pkgcachegen.cc
index a472babeb..d8f161e6d 100644
--- a/apt-pkg/pkgcachegen.cc
+++ b/apt-pkg/pkgcachegen.cc
@@ -177,6 +177,14 @@ void pkgCacheGenerator::ReMap(void const * const oldMap, void const * const newM
for (std::vector<pkgCache::RlsFileIterator*>::const_iterator i = Dynamic<pkgCache::RlsFileIterator>::toReMap.begin();
i != Dynamic<pkgCache::RlsFileIterator>::toReMap.end(); ++i)
(*i)->ReMap(oldMap, newMap);
+ for (APT::StringView* ViewP : Dynamic<APT::StringView>::toReMap) {
+ // Ignore views outside of the cache.
+ if (ViewP->data() < static_cast<const char*>(oldMap)
+ || ViewP->data() > static_cast<const char*>(oldMap) + oldSize)
+ continue;
+ const char *data = ViewP->data() + (static_cast<const char*>(newMap) - static_cast<const char*>(oldMap));
+ *ViewP = StringView(data , ViewP->size());
+ }
} /*}}}*/
// CacheGenerator::WriteStringInMap /*{{{*/
map_stringitem_t pkgCacheGenerator::WriteStringInMap(const char *String,
@@ -503,6 +511,7 @@ bool pkgCacheGenerator::AddNewDescription(ListParser &List, pkgCache::VerIterato
/* This creates a new group structure and adds it to the hash table */
bool pkgCacheGenerator::NewGroup(pkgCache::GrpIterator &Grp, StringView Name)
{
+ Dynamic<StringView> DName(Name);
Grp = Cache.FindGrp(Name);
if (Grp.end() == false)
return true;
@@ -537,6 +546,8 @@ bool pkgCacheGenerator::NewGroup(pkgCache::GrpIterator &Grp, StringView Name)
bool pkgCacheGenerator::NewPackage(pkgCache::PkgIterator &Pkg, StringView Name,
StringView Arch) {
pkgCache::GrpIterator Grp;
+ Dynamic<StringView> DName(Name);
+ Dynamic<StringView> DArch(Arch);
Dynamic<pkgCache::GrpIterator> DynGrp(Grp);
if (unlikely(NewGroup(Grp, Name) == false))
return false;
@@ -1014,6 +1025,9 @@ bool pkgCacheListParser::NewDepends(pkgCache::VerIterator &Ver,
{
pkgCache::GrpIterator Grp;
Dynamic<pkgCache::GrpIterator> DynGrp(Grp);
+ Dynamic<StringView> DynPackageName(PackageName);
+ Dynamic<StringView> DynArch(Arch);
+ Dynamic<StringView> DynVersion(Version);
if (unlikely(Owner->NewGroup(Grp, PackageName) == false))
return false;
@@ -1081,6 +1095,9 @@ bool pkgCacheListParser::NewProvides(pkgCache::VerIterator &Ver,
uint8_t const Flags)
{
pkgCache const &Cache = Owner->Cache;
+ Dynamic<StringView> DynPkgName(PkgName);
+ Dynamic<StringView> DynArch(PkgArch);
+ Dynamic<StringView> DynVersion(Version);
// We do not add self referencing provides
if (Ver.ParentPkg().Name() == PkgName && (PkgArch == Ver.ParentPkg().Arch() ||
@@ -1134,6 +1151,8 @@ bool pkgCacheListParser::NewProvidesAllArch(pkgCache::VerIterator &Ver, StringVi
pkgCache &Cache = Owner->Cache;
pkgCache::GrpIterator Grp = Cache.FindGrp(Package);
Dynamic<pkgCache::GrpIterator> DynGrp(Grp);
+ Dynamic<StringView> DynPackage(Package);
+ Dynamic<StringView> DynVersion(Version);
if (Grp.end() == true)
return NewProvides(Ver, Package, Cache.NativeArch(), Version, Flags);