BUG: Update both RPATH and RUNPATH entries

During installation the RPATH and RUNPATH entries of ELF binaries are
edited to match the user specification.  Usually either one entry is
present or both entries refer to the same string literal.  In the case
that they are both present and refer to separate string literals we need
to update both.  I have never seen this case in practice, but we should
do this just in case.

Source/cmSystemTools.cxx

@@ -2329,6 +2329,16 @@ std::string::size_type cmSystemToolsFindRPath(std::string const& have,
 }
 #endif
 
+#if defined(CMAKE_USE_ELF_PARSER)
+struct cmSystemToolsRPathInfo
+{
+  unsigned long Position;
+  unsigned long Size;
+  std::string Name;
+  std::string Value;
+};
+#endif
+
 //----------------------------------------------------------------------------
 bool cmSystemTools::ChangeRPath(std::string const& file,
                                 std::string const& oldRPath,
@@ -2341,37 +2351,71 @@ bool cmSystemTools::ChangeRPath(std::string const& file,
     {
     *changed = false;
     }
-  unsigned long rpathPosition = 0;
-  unsigned long rpathSize = 0;
-  std::string rpathPrefix;
-  std::string rpathSuffix;
+  int rp_count = 0;
+  cmSystemToolsRPathInfo rp[2];
   {
   // Parse the ELF binary.
   cmELF elf(file.c_str());
 
-  // Get the RPATH or RUNPATH entry from it.
-  cmELF::StringEntry const* se = elf.GetRPath();
-  if(!se)
+  // Get the RPATH and RUNPATH entries from it.
+  int se_count = 0;
+  cmELF::StringEntry const* se[2] = {0, 0};
+  const char* se_name[2] = {0, 0};
+  if(cmELF::StringEntry const* se_rpath = elf.GetRPath())
     {
-    se = elf.GetRunPath();
+    se[se_count] = se_rpath;
+    se_name[se_count] = "RPATH";
+    ++se_count;
+    }
+  if(cmELF::StringEntry const* se_runpath = elf.GetRunPath())
+    {
+    se[se_count] = se_runpath;
+    se_name[se_count] = "RUNPATH";
+    ++se_count;
+    }
+  if(se_count == 0)
+    {
+    if(newRPath.empty())
+      {
+      // The new rpath is empty and there is no rpath anyway so it is
+      // okay.
+      return true;
+      }
+    else
+      {
+      if(emsg)
+        {
+        *emsg = "No valid ELF RPATH or RUNPATH entry exists in the file; ";
+        *emsg += elf.GetErrorMessage();
+        }
+      return false;
+      }
     }
 
-  if(se)
+  for(int i=0; i < se_count; ++i)
     {
+    // If both RPATH and RUNPATH refer to the same string literal it
+    // needs to be changed only once.
+    if(rp_count && rp[0].Position == se[i]->Position)
+      {
+      continue;
+      }
+
     // Make sure the current rpath contains the old rpath.
-    std::string::size_type pos = cmSystemToolsFindRPath(se->Value, oldRPath);
+    std::string::size_type pos =
+      cmSystemToolsFindRPath(se[i]->Value, oldRPath);
     if(pos == std::string::npos)
       {
       // If it contains the new rpath instead then it is okay.
-      if(cmSystemToolsFindRPath(se->Value, newRPath) != std::string::npos)
+      if(cmSystemToolsFindRPath(se[i]->Value, newRPath) != std::string::npos)
         {
-        return true;
+        continue;
         }
       if(emsg)
         {
         cmOStringStream e;
-        e << "The current RPATH is:\n"
-          << "  " << se->Value << "\n"
+        e << "The current " << se_name[i] << " is:\n"
+          << "  " << se[i]->Value << "\n"
           << "which does not contain:\n"
           << "  " << oldRPath << "\n"
           << "as was expected.";
@@ -2380,47 +2424,43 @@ bool cmSystemTools::ChangeRPath(std::string const& file,
       return false;
       }
 
-    // Store information about the entry.
-    rpathPosition = se->Position;
-    rpathSize = se->Size;
+    // Store information about the entry in the file.
+    rp[rp_count].Position = se[i]->Position;
+    rp[rp_count].Size = se[i]->Size;
+    rp[rp_count].Name = se_name[i];
 
-    // Store the part of the path we must preserve.
-    rpathPrefix = se->Value.substr(0, pos);
-    rpathSuffix = se->Value.substr(pos+oldRPath.length(), oldRPath.npos);
-    }
-  else if(newRPath.empty())
-    {
-    // The new rpath is empty and there is no rpath anyway so it is
-    // okay.
-    return true;
-    }
-  else
-    {
-    if(emsg)
+    // Construct the new value which preserves the part of the path
+    // not being changed.
+    rp[rp_count].Value = se[i]->Value.substr(0, pos);
+    rp[rp_count].Value += newRPath;
+    rp[rp_count].Value += se[i]->Value.substr(pos+oldRPath.length(),
+                                              oldRPath.npos);
+
+    // Make sure there is enough room to store the new rpath and at
+    // least one null terminator.
+    if(rp[rp_count].Size < rp[rp_count].Value.length()+1)
       {
-      *emsg = "No valid ELF RPATH entry exists in the file; ";
-      *emsg += elf.GetErrorMessage();
+      if(emsg)
+        {
+        *emsg = "The replacement path is too long for the ";
+        *emsg += se_name[i];
+        *emsg += " entry.";
+        }
+      return false;
       }
-    return false;
+
+    // This entry is ready for update.
+    ++rp_count;
     }
   }
-  // Compute the full new rpath.
-  std::string rpath = rpathPrefix;
-  rpath += newRPath;
-  rpath += rpathSuffix;
 
-  // Make sure there is enough room to store the new rpath and at
-  // least one null terminator.
-  if(rpathSize < rpath.length()+1)
+  // If no runtime path needs to be changed, we are done.
+  if(rp_count == 0)
     {
-    if(emsg)
-      {
-      *emsg = "The replacement RPATH is too long.";
-      }
-    return false;
+    return true;
     }
 
-  // Open the file for update and seek to the RPATH position.
+  // Open the file for update.
   std::ofstream f(file.c_str(),
                   std::ios::in | std::ios::out | std::ios::binary);
   if(!f)
@@ -2431,40 +2471,49 @@ bool cmSystemTools::ChangeRPath(std::string const& file,
       }
     return false;
     }
-  if(!f.seekp(rpathPosition))
+
+  // Store the new RPATH and RUNPATH strings.
+  for(int i=0; i < rp_count; ++i)
     {
-    if(emsg)
+    // Seek to the RPATH position.
+    if(!f.seekp(rp[i].Position))
       {
-      *emsg = "Error seeking to RPATH position.";
+      if(emsg)
+        {
+        *emsg = "Error seeking to ";
+        *emsg += rp[i].Name;
+        *emsg += " position.";
+        }
+      return false;
       }
-    return false;
-    }
 
-  // Write the new rpath.  Follow it with enough null terminators to
-  // fill the string table entry.
-  f << rpath;
-  for(unsigned long i=rpath.length(); i < rpathSize; ++i)
-    {
-    f << '\0';
-    }
+    // Write the new rpath.  Follow it with enough null terminators to
+    // fill the string table entry.
+    f << rp[i].Value;
+    for(unsigned long j=rp[i].Value.length(); j < rp[i].Size; ++j)
+      {
+      f << '\0';
+      }
 
-  // Make sure everything was okay.
-  if(f)
-    {
-    if(changed)
+    // Make sure it wrote correctly.
+    if(!f)
       {
-      *changed = true;
+      if(emsg)
+        {
+        *emsg = "Error writing the new ";
+        *emsg += rp[i].Name;
+        *emsg += " string to the file.";
+        }
+      return false;
       }
-    return true;
     }
-  else
+
+  // Everything was updated successfully.
+  if(changed)
     {
-    if(emsg)
-      {
-      *emsg = "Error writing the new rpath to the file.";
-      }
-    return false;
+    *changed = true;
     }
+  return true;
 #else
   (void)file;
   (void)oldRPath;