[PATCH 1/6] sysroot: fix short release -r option handling in case of sysroot read System.map symbols

[Victor Kamensky <kamensky at cisco dot com>]

Add sysroot to system_map_path + "/boot/System.map" case. Otherwise
stap tries to look symbols on host system and it produce error like this:

> Kernel symbol table /boot/System.map-4.9.78-yocto-standard unavailable, (No such file or directory)

Here are steps to reproduce the issue. Note <sysroot> is produced by yocto
poky build. Under <sysroot>/lib/modules/4.9.78-yocto-standard/build there
is no System.map file; instead it is installed under <sysroot>/boot directory.

[kamensky@coreos-lnx2 tests]$ cat meminfo.stp
probe kernel.function("meminfo_proc_show") {
        println("meminfo_proc_show called")
}
[kamensky@coreos-lnx2 tests]$ export SYSTEMTAP_DEBUGINFO_PATH=+:.debug:build
[kamensky@coreos-lnx2 tests]$ /home/wd8/systemtap/20180208_2/packages/bin/stap --sysroot=/home/wd8/yocto/20180128/build_x86_64/tmp/work/intel_corei7_64-poky-linux/kdevel-console-devel-image/1.0-r0/rootfs -a x86_64 -r 4.9.78-yocto-standard -B CROSS_COMPILE=x86_64-poky-linux- --sysenv=PATH=/usr/bin:/bin:/usr/sbin:/sbin --sysenv=LD_LIBRARY_PATH=/lib:/usr/lib -p4 -v -v -m meminfo meminfo.stp
Systemtap translator/driver (version 3.3/0.170, commit release-3.2-92-g26c5e3c03c94 + changes)
Copyright (C) 2005-2017 Red Hat, Inc. and others
This is free software; see the source for copying conditions.
tested kernel versions: 2.6.18 ... 4.14-rc4
enabled features: BPF PYTHON2 PYTHON3 LIBXML2 NLS
Created temporary directory "/tmp/staprq4IGE"
Session arch: x86_64 release: 4.9.78-yocto-standard
Kernel symbol table /home/wd8/yocto/20180128/build_x86_64/tmp/work/intel_corei7_64-poky-linux/kdevel-console-devel-image/1.0-r0/rootfs//lib/modules/4.9.78-yocto-standard/build/System.map unavailable, (No such file or directory)
Kernel symbol table /boot/System.map-4.9.78-yocto-standard unavailable, (No such file or directory)
WARNING: Kernel function symbol table missing [man warning::symbols]
<snip>
semantic error: while resolving probe point: identifier 'kernel' at meminfo.stp:1:7
   thrown from: ../systemtap/elaborate.cxx:1080
        source: probe kernel.function("meminfo_proc_show") {
                      ^

semantic error: missing x86_64 kernel/module debuginfo [man warning::debuginfo] under '/home/wd8/yocto/20180128/build_x86_64/tmp/work/intel_corei7_64-poky-linux/kdevel-console-devel-image/1.0-r0/rootfs//lib/modules/4.9.78-yocto-standard/build'
   thrown from: ../systemtap/dwflpp.cxx:340

Signed-off-by: Victor Kamensky <kamensky@cisco.com>
---
 session.cxx | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/session.cxx b/session.cxx
index 5800f28fd..ebec94edb 100644
--- a/session.cxx
+++ b/session.cxx
@@ -2038,7 +2038,7 @@ systemtap_session::parse_kernel_functions ()
 	clog << _F("Kernel symbol table %s unavailable, (%s)",
 		   system_map_path.c_str(), strerror(errno)) << endl;
 
-      system_map_path = "/boot/System.map-" + kernel_release;
+      system_map_path = sysroot + "/boot/System.map-" + kernel_release;
       system_map.clear();
       system_map.open(system_map_path.c_str(), ifstream::in);
       if (! system_map.is_open())
-- 
2.14.3