[PATCH 6/6] sysroot: _stp_umodule_relocate needs receive target file path

[Victor Kamensky <kamensky@cisco.com>]

Strip of sysroot from module name is required when
_stp_umodule_relocate call is generated. Otherwise path won't
match path on target and could will fail to calculated address
within the file. Note in another place in tapsets.cxx where
_stp_umodule_relocate is emitted path_remove_sysroot is already
applied.

Here are steps how to reproduce the issue. Note <sysroot> is produced by
yocto poky build.

[kamensky@coreos-lnx2 tests]$ cat od.stp
probe process("/usr/bin/od.coreutils").function("main").call {
  printf ("%s: flag_dump_strings=0x%x\n", ppfunc(), $flag_dump_strings)
}
[kamensky@coreos-lnx2 tests]$ /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 -k -m od od.stp
od.ko
Keeping temporary directory "/tmp/stapdnaaGF"
[kamensky@coreos-lnx2 tests]$ grep _stp_umodule_relocate /tmp/stapdnaaGF/od_src.c
  l->__retvalue = uderef(1, ((((int64_t) (/* pragma:vma */ ({ unsigned long addr = 0; addr = _stp_umodule_relocate ("/home/wd8/yocto/20180128/build_x86_64/tmp/work/intel_corei7_64-poky-linux/kdevel-console-devel-image/1.0-r0/rootfs/usr/bin/od.coreutils", 0x212212, current); addr; }))))));

Note above _stp_umodule_relocate call was emitted with file path
on the host, it will fail once executed on target.

Signed-off-by: Victor Kamensky <kamensky@cisco.com>
---
 loc2stap.cxx | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/loc2stap.cxx b/loc2stap.cxx
index 4818ee088..e2339a45e 100644
--- a/loc2stap.cxx
+++ b/loc2stap.cxx
@@ -17,6 +17,7 @@
 
 #include "loc2stap.h"
 #include "dwflpp.h"
+#include "tapsets.h"
 
 #if ! _ELFUTILS_PREREQ(0, 153)
 #define DW_OP_GNU_entry_value 0xf3
@@ -106,7 +107,7 @@ location_context::translate_address(Dwarf_Addr addr)
           c = "/* pragma:vma */ "
               "({ unsigned long addr = 0; "
               "addr = _stp_umodule_relocate (\""
-              + resolve_path(dw->module_name.c_str()) + "\", "
+              + path_remove_sysroot(dw->sess, resolve_path(dw->module_name.c_str())) + "\", "
               + lex_cast_hex (addr)
 	      + ", current); addr; })";
 	}
-- 
2.14.3