From 41efad04730be89889d1483719f9a6c9396dc250 Mon Sep 17 00:00:00 2001
From: David Smith <dsmith@redhat.com>
Date: Wed, 14 Mar 2018 17:05:25 -0500
Subject: [PATCH] Make sure sysroot paths don't end with a slash.

* session.cxx (parse_cmdline): Make sure a sysroot path does not end with
  a '/', since we build paths like: sysroot + "/lib/modules". If the
  sysroot path ends with a '/', we end up with paths like
  '/SYSROOT//lib/modules'.
  (setup_kernel_release): Take a string parameter, not a character pointer.
* session.h: Update setup_kernel_release() prototype.

Upstream-Status: Backport
Signed-off-by: Victor Kamensky <kamensky@cisco.com>
---
 session.cxx | 34 ++++++++++++++++++++++++++--------
 session.h   |  2 +-
 2 files changed, 27 insertions(+), 9 deletions(-)

Index: git/session.cxx
===================================================================
--- git.orig/session.cxx
+++ git/session.cxx
@@ -722,6 +722,9 @@ systemtap_session::parse_cmdline (int ar
   client_options_disallowed_for_unprivileged = "";
   std::set<std::string> additional_unwindsym_modules;
   struct rlimit our_rlimit;
+  bool sysroot_option_seen = false;
+  string kernel_release_value;
+
   while (true)
     {
       char * num_endptr;
@@ -887,7 +890,7 @@ systemtap_session::parse_cmdline (int ar
 	    // Note that '-' must come last in a regex bracket expression.
             assert_regexp_match("-r parameter from client", optarg, "^[a-z0-9_.+-]+$");
 	  server_args.push_back (string ("-") + (char)grc + optarg);
-          setup_kernel_release(optarg);
+	  kernel_release_value = optarg;
           break;
 
         case 'a':
@@ -1473,7 +1476,7 @@ systemtap_session::parse_cmdline (int ar
 	  if (client_options) {
 	      cerr << _F("ERROR: %s invalid with %s", "--sysroot", "--client-options") << endl;
 	      return 1;
-	  } else if (!sysroot.empty()) {
+	  } else if (sysroot_option_seen) {
 	      cerr << "ERROR: multiple --sysroot options not supported" << endl;
 	      return 1;
 	  } else {
@@ -1487,11 +1490,17 @@ systemtap_session::parse_cmdline (int ar
 
 	      sysroot = string(spath);
 	      free (spath);
-	      if (sysroot[sysroot.size() - 1] != '/')
-		  sysroot.append("/");
 
-	      break;
+	      // We do path creation like this:
+	      //   sysroot + "/lib/modules"
+	      // So, we don't want the sysroot path to end with a '/',
+	      // otherwise we'll end up with '/foo//lib/modules'.
+	      if (sysroot.back() == '/') {
+		  sysroot.pop_back();
+	      }
 	  }
+	  sysroot_option_seen = true;
+	  break;
 
 	case LONG_OPT_SYSENV:
 	  if (client_options) {
@@ -1501,7 +1510,7 @@ systemtap_session::parse_cmdline (int ar
 	      string sysenv_str = optarg;
 	      string value;
 	      size_t pos;
-	      if (sysroot.empty()) {
+	      if (! sysroot_option_seen) {
 		  cerr << "ERROR: --sysenv must follow --sysroot" << endl;
 		  return 1;
 	      }
@@ -1646,6 +1655,15 @@ systemtap_session::parse_cmdline (int ar
 	}
     }
 
+  if (! kernel_release_value.empty())
+  {
+      setup_kernel_release(kernel_release_value);
+  }
+  else if (! sysroot.empty())
+  {
+      kernel_build_tree = sysroot + "/lib/modules/" + kernel_release  + "/build";
+  }
+
   return 0;
 }
 
@@ -2152,7 +2170,7 @@ void systemtap_session::insert_loaded_mo
 }
 
 void
-systemtap_session::setup_kernel_release (const char* kstr) 
+systemtap_session::setup_kernel_release (const string& kstr) 
 {
   // Sometimes we may get dupes here... e.g. a server may have a full
   // -r /path/to/kernel followed by a client's -r kernel.
@@ -2183,7 +2201,7 @@ systemtap_session::setup_kernel_release
   else
     {
       update_release_sysroot = true;
-      kernel_release = string (kstr);
+      kernel_release = kstr;
       if (!kernel_release.empty())
         kernel_build_tree = "/lib/modules/" + kernel_release + "/build";
 
Index: git/session.h
===================================================================
--- git.orig/session.h
+++ git/session.h
@@ -144,7 +144,7 @@ public:
 
   // NB: It is very important for all of the above (and below) fields
   // to be cleared in the systemtap_session ctor (session.cxx).
-  void setup_kernel_release (const char* kstr);
+  void setup_kernel_release (const std::string& kstr);
   void insert_loaded_modules ();
 
   // command line parsing