ld.so: command argument "--preload"
Commit Message
Thanks, Florian and Carlos, for your guidance. This is my patch,
relative to master source, as pulled two days ago.
Comments
* David Newall:
> +${test_wrapper} $rtld --library-path $library_path --preload $preload $test_program 2>&1 && rc=0 || rc=$?
I would suggest to use "" around shell variables where applicable, and
wrap this long line (using \).
There are also a few stylistic issues we need to fix: Two whitespace
problems (”. */” at end of comments, space before parenthesis in
function call, not after it). The copyright statement for the new file
needs a bit polishing.
But the change as such looks okay to me. We can commit this for your
after 2.30 development opens in Feburary. I'll supply a new NEWS entry
and a ChangeLog entry, too.
Thanks,
Florian
@@ -353,7 +353,8 @@ endif
ifeq (yes,$(build-shared))
ifeq ($(run-built-tests),yes)
-tests-special += $(objpfx)tst-pathopt.out $(objpfx)tst-rtld-load-self.out
+tests-special += $(objpfx)tst-pathopt.out $(objpfx)tst-rtld-load-self.out \
+ $(objpfx)tst-rtld-preload.out
endif
tests-special += $(objpfx)check-textrel.out $(objpfx)check-execstack.out \
$(objpfx)check-localplt.out $(objpfx)check-initfini.out
@@ -882,6 +883,15 @@ $(objpfx)tst-rtld-load-self.out: tst-rtld-load-self.sh $(objpfx)ld.so
$(SHELL) $^ '$(test-wrapper)' '$(test-wrapper-env)' > $@; \
$(evaluate-test)
+tst-rtld-preload-OBJS = $(subst $(empty) ,:,$(strip $(preloadtest-preloads:=.so)))
+$(objpfx)tst-rtld-preload.out: tst-rtld-preload.sh $(objpfx)ld.so \
+ $(objpfx)preloadtest \
+ $(preloadtest-preloads:%=$(objpfx)%.so)
+ $(SHELL) $< $(objpfx)ld.so $(objpfx)preloadtest \
+ '$(test-wrapper)' '$(test-wrapper-env)' '$(run_program_env)' \
+ '$(rpath-link)' '$(tst-rtld-preload-OBJS)' > $@; \
+ $(evaluate-test)
+
$(objpfx)initfirst: $(libdl)
$(objpfx)initfirst.out: $(objpfx)firstobj.so
@@ -826,15 +826,18 @@ static const char *library_path attribute_relro;
static const char *preloadlist attribute_relro;
/* Nonzero if information about versions has to be printed. */
static int version_info attribute_relro;
+/* The preload list passed as a command argument. */
+static const char *preloadarg attribute_relro;
/* The LD_PRELOAD environment variable gives list of libraries
separated by white space or colons that are loaded before the
executable's dependencies and prepended to the global scope list.
(If the binary is running setuid all elements containing a '/' are
ignored since it is insecure.) Return the number of preloads
- performed. */
+ performed. Ditto for --preload command argument. */
unsigned int
-handle_ld_preload (const char *preloadlist, struct link_map *main_map)
+handle_preload_list (const char *preloadlist, struct link_map *main_map,
+ const char *where)
{
unsigned int npreloads = 0;
const char *p = preloadlist;
@@ -858,7 +861,7 @@ handle_ld_preload (const char *preloadlist, struct link_map *main_map)
++p;
if (dso_name_valid_for_suid (fname))
- npreloads += do_preload (fname, main_map, "LD_PRELOAD");
+ npreloads += do_preload (fname, main_map, where);
}
return npreloads;
}
@@ -978,6 +981,13 @@ dl_main (const ElfW(Phdr) *phdr,
_dl_argc -= 2;
_dl_argv += 2;
}
+ else if (! strcmp(_dl_argv[1], "--preload") && _dl_argc > 2)
+ {
+ preloadarg = _dl_argv[2];
+ _dl_skip_args += 2;
+ _dl_argc -= 2;
+ _dl_argv += 2;
+ }
else
break;
@@ -1006,7 +1016,8 @@ of this helper program; chances are you did not intend to run this program.\n\
variable LD_LIBRARY_PATH\n\
--inhibit-rpath LIST ignore RUNPATH and RPATH information in object names\n\
in LIST\n\
- --audit LIST use objects named in LIST as auditors\n");
+ --audit LIST use objects named in LIST as auditors\n\
+ --preload LIST preload objects named in LIST\n");
++_dl_skip_args;
--_dl_argc;
@@ -1620,7 +1631,16 @@ ERROR: ld.so: object '%s' cannot be loaded as audit interface: %s; ignored.\n",
if (__glibc_unlikely (preloadlist != NULL))
{
HP_TIMING_NOW (start);
- npreloads += handle_ld_preload (preloadlist, main_map);
+ npreloads += handle_preload_list (preloadlist, main_map, "LD_PRELOAD");
+ HP_TIMING_NOW (stop);
+ HP_TIMING_DIFF (diff, start, stop);
+ HP_TIMING_ACCUM_NT (load_time, diff);
+ }
+
+ if (__glibc_unlikely (preloadarg != NULL))
+ {
+ HP_TIMING_NOW (start);
+ npreloads += handle_preload_list (preloadarg, main_map, "--preload");
HP_TIMING_NOW (stop);
HP_TIMING_DIFF (diff, start, stop);
HP_TIMING_ACCUM_NT (load_time, diff);
new file mode 100755
@@ -0,0 +1,37 @@
+#!/bin/sh
+# Test how rtld loads itself.
+# Copyright (C) 2012-2016 Free Software Foundation, Inc.
+# This file is part of the GNU C Library.
+#
+
+# The GNU C Library is free software; you can redistribute it and/or
+# modify it under the terms of the GNU Lesser General Public
+# License as published by the Free Software Foundation; either
+# version 2.1 of the License, or (at your option) any later version.
+
+# The GNU C Library is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+# Lesser General Public License for more details.
+
+# You should have received a copy of the GNU Lesser General Public
+# License along with the GNU C Library; if not, see
+# <http://www.gnu.org/licenses/>.
+
+set -e
+
+rtld=$1
+test_program=$2
+test_wrapper=$3
+test_wrapper_env=$4
+run_program_env=$5
+library_path=$6
+preload=$7
+
+echo "# [${test_wrapper}] [$rtld] [--library-path] [$library_path] [--preload] [$preload] [$test_program]"
+${test_wrapper_env} \
+${run_program_env} \
+${test_wrapper} $rtld --library-path $library_path --preload $preload $test_program 2>&1 && rc=0 || rc=$?
+echo "# exit status $rc"
+
+exit $rc