reset HOME, USER(NAME), TMPDIR & SHELL in DropPrivileges

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

diff --git a/apt-pkg/contrib/srvrec.cc b/apt-pkg/contrib/srvrec.cc
index b4a3d97d25d9abe0a04781967a5807f4a02ea290..327e59937eda49b4bfdaa66efae58f4ead07efbd 100644 (file)
--- a/apt-pkg/contrib/srvrec.cc
+++ b/apt-pkg/contrib/srvrec.cc
@@ -13,9 +13,10 @@
 #include <netinet/in.h>
 #include <arpa/nameser.h>
 #include <resolv.h>
-#include <chrono>
+#include <time.h>
 
 #include <algorithm>
+#include <tuple>
 
 #include <apt-pkg/configuration.h>
 #include <apt-pkg/error.h>
@@ -25,11 +26,22 @@
 #include "srvrec.h"
 
 
+bool SrvRec::operator==(SrvRec const &other) const
+{
+   return (std::tie(target, priority, weight, port) ==
+           std::tie(other.target, other.priority, other.weight, other.port));
+}
+
 bool GetSrvRecords(std::string host, int port, std::vector<SrvRec> &Result)
 {
    std::string target;
-   struct servent *s_ent = getservbyport(htons(port), "tcp");
-   if (s_ent == NULL)
+   int res;
+   struct servent s_ent_buf;
+   struct servent *s_ent = nullptr;
+   std::vector<char> buf(1024);
+
+   res = getservbyport_r(htons(port), "tcp", &s_ent_buf, buf.data(), buf.size(), &s_ent);
+   if (res != 0 || s_ent == nullptr)
       return false;
 
    strprintf(target, "_%s._tcp.%s", s_ent->s_name, host.c_str());
@@ -68,7 +80,6 @@ bool GetSrvRecords(std::string name, std::vector<SrvRec> &Result)
    unsigned char *pt = answer+sizeof(HEADER)+compressed_name_len+QFIXEDSZ;
    while ((int)Result.size() < answer_count && pt < answer+answer_len)
    {
-      SrvRec rec;
       u_int16_t type, klass, priority, weight, port, dlen;
       char buf[MAXDNAME];
 
@@ -105,11 +116,7 @@ bool GetSrvRecords(std::string name, std::vector<SrvRec> &Result)
       pt += compressed_name_len;
 
       // add it to our class
-      rec.priority = priority;
-      rec.weight = weight;
-      rec.port = port;
-      rec.target = buf;
-      Result.push_back(rec);
+      Result.emplace_back(buf, priority, weight, port);
    }
 
    // implement load balancing as specified in RFC-2782
@@ -173,21 +180,14 @@ SrvRec PopFromSrvRecs(std::vector<SrvRec> &Recs)
 #endif
 
    // shuffle in a very simplistic way for now (equal weights)
-   std::vector<SrvRec>::iterator I, J;
-   I = J = Recs.begin();
-   for(;I != Recs.end(); ++I)
-   {
-      if(I->priority != J->priority)
-         break;
-   }
-
-   // FIXME: meeeeh, where to init this properly
-   unsigned seed = std::chrono::system_clock::now().time_since_epoch().count();
-   std::shuffle(J, I, std::default_random_engine(seed));
-
-   // meh, no pop_front() in std::vector?
-   SrvRec selected = *Recs.begin();
-   Recs.erase(Recs.begin());
+   std::vector<SrvRec>::iterator I = Recs.begin();
+   std::vector<SrvRec>::iterator const J = std::find_if(Recs.begin(), Recs.end(),
+        [&I](SrvRec const &J) { return I->priority != J.priority; });
+
+   // clock seems random enough.
+   I += std::max(static_cast<clock_t>(0), clock()) % std::distance(I, J);
+   SrvRec const selected = std::move(*I);
+   Recs.erase(I);
 
    if (_config->FindB("Debug::Acquire::SrvRecs", false) == true)
       std::cerr << "PopFromSrvRecs: selecting " << selected.target << std::endl;