* [PATCH v5] elf: Fix DFS sorting algorithm for LD_TRACE_LOADED_OBJECTS with missing libraries (BZ #28868)
@ 2022-03-04 17:12 Adhemerval Zanella
2022-04-26 18:43 ` Siddhesh Poyarekar
0 siblings, 1 reply; 3+ messages in thread
From: Adhemerval Zanella @ 2022-03-04 17:12 UTC (permalink / raw)
To: libc-alpha, Florian Weimer
The _dl_map_object_deps ignores l_faked objects (set if the underlying
file can't be opened by _dl_map_object):
490 for (nlist = 0, runp = known; runp; runp = runp->next)
491 {
492 if (__builtin_expect (trace_mode, 0) && runp->map->l_faked)
493 /* This can happen when we trace the loading. */
494 --map->l_searchlist.r_nlist;
495 else
496 {
497 if (runp->map == map)
498 map_index = nlist;
499 map->l_searchlist.r_list[nlist++] = runp->map;
500 }
501
502 /* Now clear all the mark bits we set in the objects on the search list
503 to avoid duplicates, so the next call starts fresh. */
504 runp->map->l_reserved = 0;
505 }
If there any missing libraries being processed, they will not be
considered on final nlist size passed on _dl_sort_maps later in the
function. And it is then used on _dl_sort_maps_dfs on the stack
allocated working maps:
222 /* Array to hold RPO sorting results, before we copy back to maps[]. */
223 struct link_map *rpo[nmaps];
224
225 /* The 'head' position during each DFS iteration. Note that we start at
226 one past the last element due to first-decrement-then-store (see the
227 bottom of above dfs_traversal() routine). */
228 struct link_map **rpo_head = &rpo[nmaps];
However while transversing the 'l_initfini' on dfs_traversal it will
still considere the l_faked maps and thus update rpo more times than the
allocated working 'rpo', overflowing the stack object.
As suggested in bugzilla, one option would be to avoid sorting the maps
for trace mode. However I think ignoring l_faked object does make
sense (there is one less constraint to call the sorting function), it
allows a slight less stack usage for trace, and it is slight simpler
solution.
The tests does trigger the stack overflow, however I tried to make
it more generic to check different scenarios or missing objects.
Checked on x86_64-linux-gnu.
---
v5: Refactor tests make rules.
v4: Use --soname to build the libraries, fixed typos.
v3: Removed stamp files to avoid add them as linker depedencies and
moved test evaluation to python script.
v2: Added comments and fixed the default tst-trace1 --library-path.
---
elf/Makefile | 54 ++++++++++++++++++++
elf/dl-deps.c | 2 +
elf/dl-sort-maps.c | 4 +-
elf/libtracemod1-1.c | 1 +
elf/libtracemod2-1.c | 1 +
elf/libtracemod3-1.c | 1 +
elf/libtracemod4-1.c | 1 +
elf/libtracemod5-1.c | 1 +
elf/libtracemod6.c | 1 +
elf/tst-trace1.exp | 4 ++
elf/tst-trace2.exp | 6 +++
elf/tst-trace3.exp | 6 +++
elf/tst-trace4.exp | 6 +++
elf/tst-trace5.exp | 6 +++
scripts/tst-ld-trace.py | 108 ++++++++++++++++++++++++++++++++++++++++
15 files changed, 201 insertions(+), 1 deletion(-)
create mode 100644 elf/libtracemod1-1.c
create mode 100644 elf/libtracemod2-1.c
create mode 100644 elf/libtracemod3-1.c
create mode 100644 elf/libtracemod4-1.c
create mode 100644 elf/libtracemod5-1.c
create mode 100644 elf/libtracemod6.c
create mode 100644 elf/tst-trace1.exp
create mode 100644 elf/tst-trace2.exp
create mode 100644 elf/tst-trace3.exp
create mode 100644 elf/tst-trace4.exp
create mode 100644 elf/tst-trace5.exp
create mode 100755 scripts/tst-ld-trace.py
diff --git a/elf/Makefile b/elf/Makefile
index c96924e9c2..f30f64991f 100644
--- a/elf/Makefile
+++ b/elf/Makefile
@@ -617,6 +617,11 @@ modules-names = \
libmarkermod4-2 \
libmarkermod4-3 \
libmarkermod4-4 \
+ libtracemod1-1 \
+ libtracemod2-1 \
+ libtracemod3-1 \
+ libtracemod4-1 \
+ libtracemod5-1 \
ltglobmod1 \
ltglobmod2 \
neededobj1 \
@@ -1079,6 +1084,11 @@ tests-special += \
$(objpfx)tst-initorder2-cmp.out \
$(objpfx)tst-unused-dep-cmp.out \
$(objpfx)tst-unused-dep.out \
+ $(objpfx)tst-trace1.out \
+ $(objpfx)tst-trace2.out \
+ $(objpfx)tst-trace3.out \
+ $(objpfx)tst-trace4.out \
+ $(objpfx)tst-trace5.out \
# tests-special
endif
@@ -2725,3 +2735,47 @@ $(objpfx)tst-p_align3: $(objpfx)tst-p_alignmod3.so
$(objpfx)tst-p_align3.out: tst-p_align3.sh $(objpfx)tst-p_align3
$(SHELL) $< $(common-objpfx) '$(test-program-prefix)'; \
$(evaluate-test)
+
+LDFLAGS-libtracemod1-1.so += -Wl,-soname,libtracemod1.so
+LDFLAGS-libtracemod2-1.so += -Wl,-soname,libtracemod2.so
+LDFLAGS-libtracemod3-1.so += -Wl,-soname,libtracemod3.so
+LDFLAGS-libtracemod4-1.so += -Wl,-soname,libtracemod4.so
+LDFLAGS-libtracemod5-1.so += -Wl,-soname,libtracemod5.so
+
+$(objpfx)libtracemod1-1.so: $(objpfx)libtracemod2-1.so \
+ $(objpfx)libtracemod3-1.so
+$(objpfx)libtracemod2-1.so: $(objpfx)libtracemod4-1.so \
+ $(objpfx)libtracemod5-1.so
+
+define libtracemod-x
+$(objpfx)libtracemod$(1)/libtracemod$(1).so: $(objpfx)libtracemod$(1)-1.so
+ $$(make-target-directory)
+ cp $$< $$@
+endef
+libtracemod-suffixes = 1 2 3 4 5
+$(foreach i,$(libtracemod-suffixes), $(eval $(call libtracemod-x,$(i))))
+
+define tst-trace-skeleton
+$(objpfx)tst-trace$(1).out: $(objpfx)libtracemod1/libtracemod1.so \
+ $(objpfx)libtracemod2/libtracemod2.so \
+ $(objpfx)libtracemod3/libtracemod3.so \
+ $(objpfx)libtracemod4/libtracemod4.so \
+ $(objpfx)libtracemod5/libtracemod5.so \
+ $(..)scripts/tst-ld-trace.py \
+ tst-trace$(1).exp
+ ( $(PYTHON) $(..)scripts/tst-ld-trace.py \
+ "$(test-wrapper-env) $(elf-objpfx)$(rtld-installed-name) \
+ --library-path $(common-objpfx):$(strip $(2)) \
+ $(objpfx)libtracemod1/libtracemod1.so" tst-trace$(1).exp \
+ ) > $$@; $$(evaluate-test)
+endef
+
+$(eval $(call tst-trace-skeleton,1,))
+$(eval $(call tst-trace-skeleton,2,\
+ $(objpfx)libtracemod2))
+$(eval $(call tst-trace-skeleton,3,\
+ $(objpfx)libtracemod2:$(objpfx)libtracemod3))
+$(eval $(call tst-trace-skeleton,4,\
+ $(objpfx)libtracemod2:$(objpfx)libtracemod3:$(objpfx)libtracemod4))
+$(eval $(call tst-trace-skeleton,5,\
+ $(objpfx)libtracemod2:$(objpfx)libtracemod3:$(objpfx)libtracemod4:$(objpfx)libtracemod5))
diff --git a/elf/dl-deps.c b/elf/dl-deps.c
index a2fc278256..77ff2b3895 100644
--- a/elf/dl-deps.c
+++ b/elf/dl-deps.c
@@ -473,6 +473,8 @@ _dl_map_object_deps (struct link_map *map,
for (nlist = 0, runp = known; runp; runp = runp->next)
{
+ /* _dl_sort_maps ignores l_faked object, so it is safe to not considere
+ them for nlist. */
if (__builtin_expect (trace_mode, 0) && runp->map->l_faked)
/* This can happen when we trace the loading. */
--map->l_searchlist.r_nlist;
diff --git a/elf/dl-sort-maps.c b/elf/dl-sort-maps.c
index 9e9d53ec47..96638d7ed1 100644
--- a/elf/dl-sort-maps.c
+++ b/elf/dl-sort-maps.c
@@ -140,7 +140,9 @@ static void
dfs_traversal (struct link_map ***rpo, struct link_map *map,
bool *do_reldeps)
{
- if (map->l_visited)
+ /* _dl_map_object_deps ignores l_faked objects when calculating the
+ number of maps before calling _dl_sort_maps, ignore them as well. */
+ if (map->l_visited || map->l_faked)
return;
map->l_visited = 1;
diff --git a/elf/libtracemod1-1.c b/elf/libtracemod1-1.c
new file mode 100644
index 0000000000..7c89c9a5a4
--- /dev/null
+++ b/elf/libtracemod1-1.c
@@ -0,0 +1 @@
+/* Empty */
diff --git a/elf/libtracemod2-1.c b/elf/libtracemod2-1.c
new file mode 100644
index 0000000000..7c89c9a5a4
--- /dev/null
+++ b/elf/libtracemod2-1.c
@@ -0,0 +1 @@
+/* Empty */
diff --git a/elf/libtracemod3-1.c b/elf/libtracemod3-1.c
new file mode 100644
index 0000000000..7c89c9a5a4
--- /dev/null
+++ b/elf/libtracemod3-1.c
@@ -0,0 +1 @@
+/* Empty */
diff --git a/elf/libtracemod4-1.c b/elf/libtracemod4-1.c
new file mode 100644
index 0000000000..7c89c9a5a4
--- /dev/null
+++ b/elf/libtracemod4-1.c
@@ -0,0 +1 @@
+/* Empty */
diff --git a/elf/libtracemod5-1.c b/elf/libtracemod5-1.c
new file mode 100644
index 0000000000..7c89c9a5a4
--- /dev/null
+++ b/elf/libtracemod5-1.c
@@ -0,0 +1 @@
+/* Empty */
diff --git a/elf/libtracemod6.c b/elf/libtracemod6.c
new file mode 100644
index 0000000000..7c89c9a5a4
--- /dev/null
+++ b/elf/libtracemod6.c
@@ -0,0 +1 @@
+/* Empty */
diff --git a/elf/tst-trace1.exp b/elf/tst-trace1.exp
new file mode 100644
index 0000000000..4a6f5211a6
--- /dev/null
+++ b/elf/tst-trace1.exp
@@ -0,0 +1,4 @@
+ld 1
+libc 1
+libtracemod2.so 0
+libtracemod3.so 0
diff --git a/elf/tst-trace2.exp b/elf/tst-trace2.exp
new file mode 100644
index 0000000000..e13506e2eb
--- /dev/null
+++ b/elf/tst-trace2.exp
@@ -0,0 +1,6 @@
+ld 1
+libc 1
+libtracemod2.so 1
+libtracemod3.so 0
+libtracemod4.so 0
+libtracemod5.so 0
diff --git a/elf/tst-trace3.exp b/elf/tst-trace3.exp
new file mode 100644
index 0000000000..e574549d12
--- /dev/null
+++ b/elf/tst-trace3.exp
@@ -0,0 +1,6 @@
+ld 1
+libc 1
+libtracemod2.so 1
+libtracemod3.so 1
+libtracemod4.so 0
+libtracemod5.so 0
diff --git a/elf/tst-trace4.exp b/elf/tst-trace4.exp
new file mode 100644
index 0000000000..31ca97b35b
--- /dev/null
+++ b/elf/tst-trace4.exp
@@ -0,0 +1,6 @@
+ld 1
+libc 1
+libtracemod2.so 1
+libtracemod3.so 1
+libtracemod4.so 1
+libtracemod5.so 0
diff --git a/elf/tst-trace5.exp b/elf/tst-trace5.exp
new file mode 100644
index 0000000000..5d7d953726
--- /dev/null
+++ b/elf/tst-trace5.exp
@@ -0,0 +1,6 @@
+ld 1
+libc 1
+libtracemod2.so 1
+libtracemod3.so 1
+libtracemod4.so 1
+libtracemod5.so 1
diff --git a/scripts/tst-ld-trace.py b/scripts/tst-ld-trace.py
new file mode 100755
index 0000000000..f5a4028003
--- /dev/null
+++ b/scripts/tst-ld-trace.py
@@ -0,0 +1,108 @@
+#!/usr/bin/python3
+# Dump the output of LD_TRACE_LOADED_OBJECTS in architecture neutral format.
+# Copyright (C) 2022 Free Software Foundation, Inc.
+# Copyright The GNU Toolchain Authors.
+# 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
+# <https://www.gnu.org/licenses/>.
+
+import argparse
+import os
+import subprocess
+import sys
+
+try:
+ subprocess.run
+except:
+ class _CompletedProcess:
+ def __init__(self, args, returncode, stdout=None, stderr=None):
+ self.args = args
+ self.returncode = returncode
+ self.stdout = stdout
+ self.stderr = stderr
+
+ def _run(*popenargs, input=None, timeout=None, check=False, **kwargs):
+ assert(timeout is None)
+ with subprocess.Popen(*popenargs, **kwargs) as process:
+ try:
+ stdout, stderr = process.communicate(input)
+ except:
+ process.kill()
+ process.wait()
+ raise
+ returncode = process.poll()
+ if check and returncode:
+ raise subprocess.CalledProcessError(returncode, popenargs)
+ return _CompletedProcess(popenargs, returncode, stdout, stderr)
+
+ subprocess.run = _run
+
+def is_vdso(lib):
+ return lib.startswith('linux-gate') or lib.startswith('linux-vdso')
+
+
+def parse_trace(cmd, fref):
+ new_env = os.environ.copy()
+ new_env['LD_TRACE_LOADED_OBJECTS'] = '1'
+ trace_out = subprocess.run(cmd, stdout=subprocess.PIPE, check=True,
+ universal_newlines=True, env=new_env).stdout
+ trace = []
+ for line in trace_out.splitlines():
+ line = line.strip()
+ if is_vdso(line):
+ continue
+ fields = line.split('=>' if '=>' in line else ' ')
+ lib = os.path.basename(fields[0].strip())
+ if lib.startswith('ld'):
+ lib = 'ld'
+ elif lib.startswith('libc'):
+ lib = 'libc'
+ found = 1 if fields[1].strip() != 'not found' else 0
+ trace += ['{} {}'.format(lib, found)]
+ trace = sorted(trace)
+
+ reference = sorted(line.replace('\n','') for line in fref.readlines())
+
+ ret = 0 if trace == reference else 1
+ if ret != 0:
+ for i in reference:
+ if i not in trace:
+ print("Only in {}: {}".format(fref.name, i))
+ for i in trace:
+ if i not in reference:
+ print("Only in trace: {}".format(i))
+
+ sys.exit(ret)
+
+
+def get_parser():
+ parser = argparse.ArgumentParser(description=__doc__)
+ parser.add_argument('command',
+ help='comand to run')
+ parser.add_argument('reference',
+ help='reference file to compare')
+ return parser
+
+
+def main(argv):
+ parser = get_parser()
+ opts = parser.parse_args(argv)
+ with open(opts.reference, 'r') as fref:
+ # Remove the initial 'env' command.
+ parse_trace(opts.command.split()[1:], fref)
+
+
+if __name__ == '__main__':
+ main(sys.argv[1:])
--
2.32.0
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH v5] elf: Fix DFS sorting algorithm for LD_TRACE_LOADED_OBJECTS with missing libraries (BZ #28868)
2022-03-04 17:12 [PATCH v5] elf: Fix DFS sorting algorithm for LD_TRACE_LOADED_OBJECTS with missing libraries (BZ #28868) Adhemerval Zanella
@ 2022-04-26 18:43 ` Siddhesh Poyarekar
2022-04-26 19:29 ` Adhemerval Zanella
0 siblings, 1 reply; 3+ messages in thread
From: Siddhesh Poyarekar @ 2022-04-26 18:43 UTC (permalink / raw)
To: Adhemerval Zanella, libc-alpha, Florian Weimer
The patch doesn't apply anymore (conflict in elf/Makefile), please
rebase it and post. More comments below:
On 04/03/2022 22:42, Adhemerval Zanella via Libc-alpha wrote:
> The _dl_map_object_deps ignores l_faked objects (set if the underlying
> file can't be opened by _dl_map_object):
Maybe a more precise description is that the underlying file is not
opened by _dl_map_object and the linker is in trace mode? In other
cases where the underlying file can't be opened, _dl_map_object quits
with an error.
>
> 490 for (nlist = 0, runp = known; runp; runp = runp->next)
> 491 {
> 492 if (__builtin_expect (trace_mode, 0) && runp->map->l_faked)
> 493 /* This can happen when we trace the loading. */
> 494 --map->l_searchlist.r_nlist;
> 495 else
> 496 {
> 497 if (runp->map == map)
> 498 map_index = nlist;
> 499 map->l_searchlist.r_list[nlist++] = runp->map;
> 500 }
> 501
> 502 /* Now clear all the mark bits we set in the objects on the search list
> 503 to avoid duplicates, so the next call starts fresh. */
> 504 runp->map->l_reserved = 0;
> 505 }
>
> If there any missing libraries being processed, they will not be
> considered on final nlist size passed on _dl_sort_maps later in the
> function. And it is then used on _dl_sort_maps_dfs on the stack
> allocated working maps:
>
> 222 /* Array to hold RPO sorting results, before we copy back to maps[]. */
> 223 struct link_map *rpo[nmaps];
> 224
> 225 /* The 'head' position during each DFS iteration. Note that we start at
> 226 one past the last element due to first-decrement-then-store (see the
> 227 bottom of above dfs_traversal() routine). */
> 228 struct link_map **rpo_head = &rpo[nmaps];
>
> However while transversing the 'l_initfini' on dfs_traversal it will
> still considere the l_faked maps and thus update rpo more times than the
> allocated working 'rpo', overflowing the stack object.
>
> As suggested in bugzilla, one option would be to avoid sorting the maps
> for trace mode. However I think ignoring l_faked object does make
> sense (there is one less constraint to call the sorting function), it
> allows a slight less stack usage for trace, and it is slight simpler
> solution.
>
> The tests does trigger the stack overflow, however I tried to make
> it more generic to check different scenarios or missing objects.
>
> Checked on x86_64-linux-gnu.
> ---
> v5: Refactor tests make rules.
> v4: Use --soname to build the libraries, fixed typos.
> v3: Removed stamp files to avoid add them as linker depedencies and
> moved test evaluation to python script.
> v2: Added comments and fixed the default tst-trace1 --library-path.
> ---
> elf/Makefile | 54 ++++++++++++++++++++
> elf/dl-deps.c | 2 +
> elf/dl-sort-maps.c | 4 +-
> elf/libtracemod1-1.c | 1 +
> elf/libtracemod2-1.c | 1 +
> elf/libtracemod3-1.c | 1 +
> elf/libtracemod4-1.c | 1 +
> elf/libtracemod5-1.c | 1 +
> elf/libtracemod6.c | 1 +
> elf/tst-trace1.exp | 4 ++
> elf/tst-trace2.exp | 6 +++
> elf/tst-trace3.exp | 6 +++
> elf/tst-trace4.exp | 6 +++
> elf/tst-trace5.exp | 6 +++
> scripts/tst-ld-trace.py | 108 ++++++++++++++++++++++++++++++++++++++++
> 15 files changed, 201 insertions(+), 1 deletion(-)
> create mode 100644 elf/libtracemod1-1.c
> create mode 100644 elf/libtracemod2-1.c
> create mode 100644 elf/libtracemod3-1.c
> create mode 100644 elf/libtracemod4-1.c
> create mode 100644 elf/libtracemod5-1.c
> create mode 100644 elf/libtracemod6.c
> create mode 100644 elf/tst-trace1.exp
> create mode 100644 elf/tst-trace2.exp
> create mode 100644 elf/tst-trace3.exp
> create mode 100644 elf/tst-trace4.exp
> create mode 100644 elf/tst-trace5.exp
> create mode 100755 scripts/tst-ld-trace.py
>
> diff --git a/elf/Makefile b/elf/Makefile
> index c96924e9c2..f30f64991f 100644
> --- a/elf/Makefile
> +++ b/elf/Makefile
> @@ -617,6 +617,11 @@ modules-names = \
> libmarkermod4-2 \
> libmarkermod4-3 \
> libmarkermod4-4 \
> + libtracemod1-1 \
> + libtracemod2-1 \
> + libtracemod3-1 \
> + libtracemod4-1 \
> + libtracemod5-1 \
> ltglobmod1 \
> ltglobmod2 \
> neededobj1 \
> @@ -1079,6 +1084,11 @@ tests-special += \
> $(objpfx)tst-initorder2-cmp.out \
> $(objpfx)tst-unused-dep-cmp.out \
> $(objpfx)tst-unused-dep.out \
> + $(objpfx)tst-trace1.out \
> + $(objpfx)tst-trace2.out \
> + $(objpfx)tst-trace3.out \
> + $(objpfx)tst-trace4.out \
> + $(objpfx)tst-trace5.out \
> # tests-special
> endif
>
> @@ -2725,3 +2735,47 @@ $(objpfx)tst-p_align3: $(objpfx)tst-p_alignmod3.so
> $(objpfx)tst-p_align3.out: tst-p_align3.sh $(objpfx)tst-p_align3
> $(SHELL) $< $(common-objpfx) '$(test-program-prefix)'; \
> $(evaluate-test)
> +
> +LDFLAGS-libtracemod1-1.so += -Wl,-soname,libtracemod1.so
> +LDFLAGS-libtracemod2-1.so += -Wl,-soname,libtracemod2.so
> +LDFLAGS-libtracemod3-1.so += -Wl,-soname,libtracemod3.so
> +LDFLAGS-libtracemod4-1.so += -Wl,-soname,libtracemod4.so
> +LDFLAGS-libtracemod5-1.so += -Wl,-soname,libtracemod5.so
> +
> +$(objpfx)libtracemod1-1.so: $(objpfx)libtracemod2-1.so \
> + $(objpfx)libtracemod3-1.so
> +$(objpfx)libtracemod2-1.so: $(objpfx)libtracemod4-1.so \
> + $(objpfx)libtracemod5-1.so
> +
> +define libtracemod-x
> +$(objpfx)libtracemod$(1)/libtracemod$(1).so: $(objpfx)libtracemod$(1)-1.so
> + $$(make-target-directory)
> + cp $$< $$@
> +endef
> +libtracemod-suffixes = 1 2 3 4 5
> +$(foreach i,$(libtracemod-suffixes), $(eval $(call libtracemod-x,$(i))))
> +
> +define tst-trace-skeleton
> +$(objpfx)tst-trace$(1).out: $(objpfx)libtracemod1/libtracemod1.so \
> + $(objpfx)libtracemod2/libtracemod2.so \
> + $(objpfx)libtracemod3/libtracemod3.so \
> + $(objpfx)libtracemod4/libtracemod4.so \
> + $(objpfx)libtracemod5/libtracemod5.so \
> + $(..)scripts/tst-ld-trace.py \
> + tst-trace$(1).exp
> + ( $(PYTHON) $(..)scripts/tst-ld-trace.py \
> + "$(test-wrapper-env) $(elf-objpfx)$(rtld-installed-name) \
> + --library-path $(common-objpfx):$(strip $(2)) \
> + $(objpfx)libtracemod1/libtracemod1.so" tst-trace$(1).exp \
> + ) > $$@; $$(evaluate-test)
> +endef
OK, but would it be possible to not spawn the script as a subprocess?
i.e. use {} instead of () for the recipe.
> +
> +$(eval $(call tst-trace-skeleton,1,))
> +$(eval $(call tst-trace-skeleton,2,\
> + $(objpfx)libtracemod2))
> +$(eval $(call tst-trace-skeleton,3,\
> + $(objpfx)libtracemod2:$(objpfx)libtracemod3))
> +$(eval $(call tst-trace-skeleton,4,\
> + $(objpfx)libtracemod2:$(objpfx)libtracemod3:$(objpfx)libtracemod4))
> +$(eval $(call tst-trace-skeleton,5,\
> + $(objpfx)libtracemod2:$(objpfx)libtracemod3:$(objpfx)libtracemod4:$(objpfx)libtracemod5))
OK.
> diff --git a/elf/dl-deps.c b/elf/dl-deps.c
> index a2fc278256..77ff2b3895 100644
> --- a/elf/dl-deps.c
> +++ b/elf/dl-deps.c
> @@ -473,6 +473,8 @@ _dl_map_object_deps (struct link_map *map,
>
> for (nlist = 0, runp = known; runp; runp = runp->next)
> {
> + /* _dl_sort_maps ignores l_faked object, so it is safe to not considere
consider
> + them for nlist. */
> if (__builtin_expect (trace_mode, 0) && runp->map->l_faked)
> /* This can happen when we trace the loading. */
> --map->l_searchlist.r_nlist;
> diff --git a/elf/dl-sort-maps.c b/elf/dl-sort-maps.c
> index 9e9d53ec47..96638d7ed1 100644
> --- a/elf/dl-sort-maps.c
> +++ b/elf/dl-sort-maps.c
> @@ -140,7 +140,9 @@ static void
> dfs_traversal (struct link_map ***rpo, struct link_map *map,
> bool *do_reldeps)
> {
> - if (map->l_visited)
> + /* _dl_map_object_deps ignores l_faked objects when calculating the
> + number of maps before calling _dl_sort_maps, ignore them as well. */
> + if (map->l_visited || map->l_faked)
> return;
>
> map->l_visited = 1;
OK.
> diff --git a/elf/libtracemod1-1.c b/elf/libtracemod1-1.c
> new file mode 100644
> index 0000000000..7c89c9a5a4
> --- /dev/null
> +++ b/elf/libtracemod1-1.c
> @@ -0,0 +1 @@
> +/* Empty */
> diff --git a/elf/libtracemod2-1.c b/elf/libtracemod2-1.c
> new file mode 100644
> index 0000000000..7c89c9a5a4
> --- /dev/null
> +++ b/elf/libtracemod2-1.c
> @@ -0,0 +1 @@
> +/* Empty */
> diff --git a/elf/libtracemod3-1.c b/elf/libtracemod3-1.c
> new file mode 100644
> index 0000000000..7c89c9a5a4
> --- /dev/null
> +++ b/elf/libtracemod3-1.c
> @@ -0,0 +1 @@
> +/* Empty */
> diff --git a/elf/libtracemod4-1.c b/elf/libtracemod4-1.c
> new file mode 100644
> index 0000000000..7c89c9a5a4
> --- /dev/null
> +++ b/elf/libtracemod4-1.c
> @@ -0,0 +1 @@
> +/* Empty */
> diff --git a/elf/libtracemod5-1.c b/elf/libtracemod5-1.c
> new file mode 100644
> index 0000000000..7c89c9a5a4
> --- /dev/null
> +++ b/elf/libtracemod5-1.c
> @@ -0,0 +1 @@
> +/* Empty */
> diff --git a/elf/libtracemod6.c b/elf/libtracemod6.c
> new file mode 100644
> index 0000000000..7c89c9a5a4
> --- /dev/null
> +++ b/elf/libtracemod6.c
> @@ -0,0 +1 @@
> +/* Empty */
Isn't this unused?
> diff --git a/elf/tst-trace1.exp b/elf/tst-trace1.exp
> new file mode 100644
> index 0000000000..4a6f5211a6
> --- /dev/null
> +++ b/elf/tst-trace1.exp
> @@ -0,0 +1,4 @@
> +ld 1
> +libc 1
> +libtracemod2.so 0
> +libtracemod3.so 0
OK, since libtracemod1.so depends on libtracemod2.so and libtracemod3.so
but they're not in path.
> diff --git a/elf/tst-trace2.exp b/elf/tst-trace2.exp
> new file mode 100644
> index 0000000000..e13506e2eb
> --- /dev/null
> +++ b/elf/tst-trace2.exp
> @@ -0,0 +1,6 @@
> +ld 1
> +libc 1
> +libtracemod2.so 1
> +libtracemod3.so 0
> +libtracemod4.so 0
> +libtracemod5.so 0
OK, since libtracemod2.so is now in path and libtracemod4.so and
libtracemod5.so get pulled in libtracemod2.so.
> diff --git a/elf/tst-trace3.exp b/elf/tst-trace3.exp
> new file mode 100644
> index 0000000000..e574549d12
> --- /dev/null
> +++ b/elf/tst-trace3.exp
> @@ -0,0 +1,6 @@
> +ld 1
> +libc 1
> +libtracemod2.so 1
> +libtracemod3.so 1
> +libtracemod4.so 0
> +libtracemod5.so 0
OK, since libtracemod3 is also in path.
> diff --git a/elf/tst-trace4.exp b/elf/tst-trace4.exp
> new file mode 100644
> index 0000000000..31ca97b35b
> --- /dev/null
> +++ b/elf/tst-trace4.exp
> @@ -0,0 +1,6 @@
> +ld 1
> +libc 1
> +libtracemod2.so 1
> +libtracemod3.so 1
> +libtracemod4.so 1
> +libtracemod5.so 0
OK, since libtracemod4 is also in path.
> diff --git a/elf/tst-trace5.exp b/elf/tst-trace5.exp
> new file mode 100644
> index 0000000000..5d7d953726
> --- /dev/null
> +++ b/elf/tst-trace5.exp
> @@ -0,0 +1,6 @@
> +ld 1
> +libc 1
> +libtracemod2.so 1
> +libtracemod3.so 1
> +libtracemod4.so 1
> +libtracemod5.so 1
OK, since libtracemod5 is also in path.
> diff --git a/scripts/tst-ld-trace.py b/scripts/tst-ld-trace.py
> new file mode 100755
> index 0000000000..f5a4028003
> --- /dev/null
> +++ b/scripts/tst-ld-trace.py
> @@ -0,0 +1,108 @@
> +#!/usr/bin/python3
> +# Dump the output of LD_TRACE_LOADED_OBJECTS in architecture neutral format.
> +# Copyright (C) 2022 Free Software Foundation, Inc.
> +# Copyright The GNU Toolchain Authors.
> +# 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
> +# <https://www.gnu.org/licenses/>.
> +
> +import argparse
> +import os
> +import subprocess
> +import sys
> +
> +try:
> + subprocess.run
> +except:
> + class _CompletedProcess:
> + def __init__(self, args, returncode, stdout=None, stderr=None):
> + self.args = args
> + self.returncode = returncode
> + self.stdout = stdout
> + self.stderr = stderr
> +
> + def _run(*popenargs, input=None, timeout=None, check=False, **kwargs):
> + assert(timeout is None)
> + with subprocess.Popen(*popenargs, **kwargs) as process:
> + try:
> + stdout, stderr = process.communicate(input)
> + except:
> + process.kill()
> + process.wait()
> + raise
> + returncode = process.poll()
> + if check and returncode:
> + raise subprocess.CalledProcessError(returncode, popenargs)
> + return _CompletedProcess(popenargs, returncode, stdout, stderr)
> +
> + subprocess.run = _run
> +
> +def is_vdso(lib):
> + return lib.startswith('linux-gate') or lib.startswith('linux-vdso')
OK.
> +
> +
> +def parse_trace(cmd, fref):
> + new_env = os.environ.copy()
> + new_env['LD_TRACE_LOADED_OBJECTS'] = '1'
> + trace_out = subprocess.run(cmd, stdout=subprocess.PIPE, check=True,
> + universal_newlines=True, env=new_env).stdout
> + trace = []
> + for line in trace_out.splitlines():
> + line = line.strip()
> + if is_vdso(line):
> + continue
> + fields = line.split('=>' if '=>' in line else ' ')
> + lib = os.path.basename(fields[0].strip())
> + if lib.startswith('ld'):
> + lib = 'ld'
> + elif lib.startswith('libc'):
> + lib = 'libc'
> + found = 1 if fields[1].strip() != 'not found' else 0
> + trace += ['{} {}'.format(lib, found)]
> + trace = sorted(trace)
> +
> + reference = sorted(line.replace('\n','') for line in fref.readlines())
> +
> + ret = 0 if trace == reference else 1
> + if ret != 0:
> + for i in reference:
> + if i not in trace:
> + print("Only in {}: {}".format(fref.name, i))
> + for i in trace:
> + if i not in reference:
> + print("Only in trace: {}".format(i))
> +
> + sys.exit(ret)
OK.
> +
> +
> +def get_parser():
> + parser = argparse.ArgumentParser(description=__doc__)
> + parser.add_argument('command',
> + help='comand to run')
> + parser.add_argument('reference',
> + help='reference file to compare')
> + return parser
> +
OK.
> +
> +def main(argv):
> + parser = get_parser()
> + opts = parser.parse_args(argv)
> + with open(opts.reference, 'r') as fref:
> + # Remove the initial 'env' command.
> + parse_trace(opts.command.split()[1:], fref)
> +
> +
> +if __name__ == '__main__':
> + main(sys.argv[1:])
OK.
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH v5] elf: Fix DFS sorting algorithm for LD_TRACE_LOADED_OBJECTS with missing libraries (BZ #28868)
2022-04-26 18:43 ` Siddhesh Poyarekar
@ 2022-04-26 19:29 ` Adhemerval Zanella
0 siblings, 0 replies; 3+ messages in thread
From: Adhemerval Zanella @ 2022-04-26 19:29 UTC (permalink / raw)
To: Siddhesh Poyarekar, libc-alpha, Florian Weimer
On 26/04/2022 15:43, Siddhesh Poyarekar wrote:
> The patch doesn't apply anymore (conflict in elf/Makefile), please rebase it and post. More comments below:
>
> On 04/03/2022 22:42, Adhemerval Zanella via Libc-alpha wrote:
>> The _dl_map_object_deps ignores l_faked objects (set if the underlying
>> file can't be opened by _dl_map_object):
>
> Maybe a more precise description is that the underlying file is not opened by _dl_map_object and the linker is in trace mode? In other cases where the underlying file can't be opened, _dl_map_object quits with an error.
Ack.
>
>>
>> 490 for (nlist = 0, runp = known; runp; runp = runp->next)
>> 491 {
>> 492 if (__builtin_expect (trace_mode, 0) && runp->map->l_faked)
>> 493 /* This can happen when we trace the loading. */
>> 494 --map->l_searchlist.r_nlist;
>> 495 else
>> 496 {
>> 497 if (runp->map == map)
>> 498 map_index = nlist;
>> 499 map->l_searchlist.r_list[nlist++] = runp->map;
>> 500 }
>> 501
>> 502 /* Now clear all the mark bits we set in the objects on the search list
>> 503 to avoid duplicates, so the next call starts fresh. */
>> 504 runp->map->l_reserved = 0;
>> 505 }
>>
>> If there any missing libraries being processed, they will not be
>> considered on final nlist size passed on _dl_sort_maps later in the
>> function. And it is then used on _dl_sort_maps_dfs on the stack
>> allocated working maps:
>>
>> 222 /* Array to hold RPO sorting results, before we copy back to maps[]. */
>> 223 struct link_map *rpo[nmaps];
>> 224
>> 225 /* The 'head' position during each DFS iteration. Note that we start at
>> 226 one past the last element due to first-decrement-then-store (see the
>> 227 bottom of above dfs_traversal() routine). */
>> 228 struct link_map **rpo_head = &rpo[nmaps];
>>
>> However while transversing the 'l_initfini' on dfs_traversal it will
>> still considere the l_faked maps and thus update rpo more times than the
>> allocated working 'rpo', overflowing the stack object.
>>
>> As suggested in bugzilla, one option would be to avoid sorting the maps
>> for trace mode. However I think ignoring l_faked object does make
>> sense (there is one less constraint to call the sorting function), it
>> allows a slight less stack usage for trace, and it is slight simpler
>> solution.
>>
>> The tests does trigger the stack overflow, however I tried to make
>> it more generic to check different scenarios or missing objects.
>>
>> Checked on x86_64-linux-gnu.
>> ---
>> v5: Refactor tests make rules.
>> v4: Use --soname to build the libraries, fixed typos.
>> v3: Removed stamp files to avoid add them as linker depedencies and
>> moved test evaluation to python script.
>> v2: Added comments and fixed the default tst-trace1 --library-path.
>> ---
>> elf/Makefile | 54 ++++++++++++++++++++
>> elf/dl-deps.c | 2 +
>> elf/dl-sort-maps.c | 4 +-
>> elf/libtracemod1-1.c | 1 +
>> elf/libtracemod2-1.c | 1 +
>> elf/libtracemod3-1.c | 1 +
>> elf/libtracemod4-1.c | 1 +
>> elf/libtracemod5-1.c | 1 +
>> elf/libtracemod6.c | 1 +
>> elf/tst-trace1.exp | 4 ++
>> elf/tst-trace2.exp | 6 +++
>> elf/tst-trace3.exp | 6 +++
>> elf/tst-trace4.exp | 6 +++
>> elf/tst-trace5.exp | 6 +++
>> scripts/tst-ld-trace.py | 108 ++++++++++++++++++++++++++++++++++++++++
>> 15 files changed, 201 insertions(+), 1 deletion(-)
>> create mode 100644 elf/libtracemod1-1.c
>> create mode 100644 elf/libtracemod2-1.c
>> create mode 100644 elf/libtracemod3-1.c
>> create mode 100644 elf/libtracemod4-1.c
>> create mode 100644 elf/libtracemod5-1.c
>> create mode 100644 elf/libtracemod6.c
>> create mode 100644 elf/tst-trace1.exp
>> create mode 100644 elf/tst-trace2.exp
>> create mode 100644 elf/tst-trace3.exp
>> create mode 100644 elf/tst-trace4.exp
>> create mode 100644 elf/tst-trace5.exp
>> create mode 100755 scripts/tst-ld-trace.py
>>
>> diff --git a/elf/Makefile b/elf/Makefile
>> index c96924e9c2..f30f64991f 100644
>> --- a/elf/Makefile
>> +++ b/elf/Makefile
>> @@ -617,6 +617,11 @@ modules-names = \
>> libmarkermod4-2 \
>> libmarkermod4-3 \
>> libmarkermod4-4 \
>> + libtracemod1-1 \
>> + libtracemod2-1 \
>> + libtracemod3-1 \
>> + libtracemod4-1 \
>> + libtracemod5-1 \
>> ltglobmod1 \
>> ltglobmod2 \
>> neededobj1 \
>> @@ -1079,6 +1084,11 @@ tests-special += \
>> $(objpfx)tst-initorder2-cmp.out \
>> $(objpfx)tst-unused-dep-cmp.out \
>> $(objpfx)tst-unused-dep.out \
>> + $(objpfx)tst-trace1.out \
>> + $(objpfx)tst-trace2.out \
>> + $(objpfx)tst-trace3.out \
>> + $(objpfx)tst-trace4.out \
>> + $(objpfx)tst-trace5.out \
>> # tests-special
>> endif
>> @@ -2725,3 +2735,47 @@ $(objpfx)tst-p_align3: $(objpfx)tst-p_alignmod3.so
>> $(objpfx)tst-p_align3.out: tst-p_align3.sh $(objpfx)tst-p_align3
>> $(SHELL) $< $(common-objpfx) '$(test-program-prefix)'; \
>> $(evaluate-test)
>> +
>> +LDFLAGS-libtracemod1-1.so += -Wl,-soname,libtracemod1.so
>> +LDFLAGS-libtracemod2-1.so += -Wl,-soname,libtracemod2.so
>> +LDFLAGS-libtracemod3-1.so += -Wl,-soname,libtracemod3.so
>> +LDFLAGS-libtracemod4-1.so += -Wl,-soname,libtracemod4.so
>> +LDFLAGS-libtracemod5-1.so += -Wl,-soname,libtracemod5.so
>> +
>> +$(objpfx)libtracemod1-1.so: $(objpfx)libtracemod2-1.so \
>> + $(objpfx)libtracemod3-1.so
>> +$(objpfx)libtracemod2-1.so: $(objpfx)libtracemod4-1.so \
>> + $(objpfx)libtracemod5-1.so
>> +
>> +define libtracemod-x
>> +$(objpfx)libtracemod$(1)/libtracemod$(1).so: $(objpfx)libtracemod$(1)-1.so
>> + $$(make-target-directory)
>> + cp $$< $$@
>> +endef
>> +libtracemod-suffixes = 1 2 3 4 5
>> +$(foreach i,$(libtracemod-suffixes), $(eval $(call libtracemod-x,$(i))))
>> +
>> +define tst-trace-skeleton
>> +$(objpfx)tst-trace$(1).out: $(objpfx)libtracemod1/libtracemod1.so \
>> + $(objpfx)libtracemod2/libtracemod2.so \
>> + $(objpfx)libtracemod3/libtracemod3.so \
>> + $(objpfx)libtracemod4/libtracemod4.so \
>> + $(objpfx)libtracemod5/libtracemod5.so \
>> + $(..)scripts/tst-ld-trace.py \
>> + tst-trace$(1).exp
>> + ( $(PYTHON) $(..)scripts/tst-ld-trace.py \
>> + "$(test-wrapper-env) $(elf-objpfx)$(rtld-installed-name) \
>> + --library-path $(common-objpfx):$(strip $(2)) \
>> + $(objpfx)libtracemod1/libtracemod1.so" tst-trace$(1).exp \
>> + ) > $$@; $$(evaluate-test)
>> +endef
>
> OK, but would it be possible to not spawn the script as a subprocess? i.e. use {} instead of () for the recipe.
>
Ack.
>> +
>> +$(eval $(call tst-trace-skeleton,1,))
>> +$(eval $(call tst-trace-skeleton,2,\
>> + $(objpfx)libtracemod2))
>> +$(eval $(call tst-trace-skeleton,3,\
>> + $(objpfx)libtracemod2:$(objpfx)libtracemod3))
>> +$(eval $(call tst-trace-skeleton,4,\
>> + $(objpfx)libtracemod2:$(objpfx)libtracemod3:$(objpfx)libtracemod4))
>> +$(eval $(call tst-trace-skeleton,5,\
>> + $(objpfx)libtracemod2:$(objpfx)libtracemod3:$(objpfx)libtracemod4:$(objpfx)libtracemod5))
>
> OK.
>
>> diff --git a/elf/dl-deps.c b/elf/dl-deps.c
>> index a2fc278256..77ff2b3895 100644
>> --- a/elf/dl-deps.c
>> +++ b/elf/dl-deps.c
>> @@ -473,6 +473,8 @@ _dl_map_object_deps (struct link_map *map,
>> for (nlist = 0, runp = known; runp; runp = runp->next)
>> {
>> + /* _dl_sort_maps ignores l_faked object, so it is safe to not considere
>
> consider
>
Ack.
>> + them for nlist. */
>> if (__builtin_expect (trace_mode, 0) && runp->map->l_faked)
>> /* This can happen when we trace the loading. */
>> --map->l_searchlist.r_nlist;
>> diff --git a/elf/dl-sort-maps.c b/elf/dl-sort-maps.c
>> index 9e9d53ec47..96638d7ed1 100644
>> --- a/elf/dl-sort-maps.c
>> +++ b/elf/dl-sort-maps.c
>> @@ -140,7 +140,9 @@ static void
>> dfs_traversal (struct link_map ***rpo, struct link_map *map,
>> bool *do_reldeps)
>> {
>> - if (map->l_visited)
>> + /* _dl_map_object_deps ignores l_faked objects when calculating the
>> + number of maps before calling _dl_sort_maps, ignore them as well. */
>> + if (map->l_visited || map->l_faked)
>> return;
>> map->l_visited = 1;
>
> OK.
>
>> diff --git a/elf/libtracemod1-1.c b/elf/libtracemod1-1.c
>> new file mode 100644
>> index 0000000000..7c89c9a5a4
>> --- /dev/null
>> +++ b/elf/libtracemod1-1.c
>> @@ -0,0 +1 @@
>> +/* Empty */
>> diff --git a/elf/libtracemod2-1.c b/elf/libtracemod2-1.c
>> new file mode 100644
>> index 0000000000..7c89c9a5a4
>> --- /dev/null
>> +++ b/elf/libtracemod2-1.c
>> @@ -0,0 +1 @@
>> +/* Empty */
>> diff --git a/elf/libtracemod3-1.c b/elf/libtracemod3-1.c
>> new file mode 100644
>> index 0000000000..7c89c9a5a4
>> --- /dev/null
>> +++ b/elf/libtracemod3-1.c
>> @@ -0,0 +1 @@
>> +/* Empty */
>> diff --git a/elf/libtracemod4-1.c b/elf/libtracemod4-1.c
>> new file mode 100644
>> index 0000000000..7c89c9a5a4
>> --- /dev/null
>> +++ b/elf/libtracemod4-1.c
>> @@ -0,0 +1 @@
>> +/* Empty */
>> diff --git a/elf/libtracemod5-1.c b/elf/libtracemod5-1.c
>> new file mode 100644
>> index 0000000000..7c89c9a5a4
>> --- /dev/null
>> +++ b/elf/libtracemod5-1.c
>> @@ -0,0 +1 @@
>> +/* Empty */
>> diff --git a/elf/libtracemod6.c b/elf/libtracemod6.c
>> new file mode 100644
>> index 0000000000..7c89c9a5a4
>> --- /dev/null
>> +++ b/elf/libtracemod6.c
>> @@ -0,0 +1 @@
>> +/* Empty */
>
> Isn't this unused?
>
It is, I will remove it.
>> diff --git a/elf/tst-trace1.exp b/elf/tst-trace1.exp
>> new file mode 100644
>> index 0000000000..4a6f5211a6
>> --- /dev/null
>> +++ b/elf/tst-trace1.exp
>> @@ -0,0 +1,4 @@
>> +ld 1
>> +libc 1
>> +libtracemod2.so 0
>> +libtracemod3.so 0
>
> OK, since libtracemod1.so depends on libtracemod2.so and libtracemod3.so but they're not in path.
>
>> diff --git a/elf/tst-trace2.exp b/elf/tst-trace2.exp
>> new file mode 100644
>> index 0000000000..e13506e2eb
>> --- /dev/null
>> +++ b/elf/tst-trace2.exp
>> @@ -0,0 +1,6 @@
>> +ld 1
>> +libc 1
>> +libtracemod2.so 1
>> +libtracemod3.so 0
>> +libtracemod4.so 0
>> +libtracemod5.so 0
>
> OK, since libtracemod2.so is now in path and libtracemod4.so and libtracemod5.so get pulled in libtracemod2.so.
>
>> diff --git a/elf/tst-trace3.exp b/elf/tst-trace3.exp
>> new file mode 100644
>> index 0000000000..e574549d12
>> --- /dev/null
>> +++ b/elf/tst-trace3.exp
>> @@ -0,0 +1,6 @@
>> +ld 1
>> +libc 1
>> +libtracemod2.so 1
>> +libtracemod3.so 1
>> +libtracemod4.so 0
>> +libtracemod5.so 0
>
> OK, since libtracemod3 is also in path.
>
>> diff --git a/elf/tst-trace4.exp b/elf/tst-trace4.exp
>> new file mode 100644
>> index 0000000000..31ca97b35b
>> --- /dev/null
>> +++ b/elf/tst-trace4.exp
>> @@ -0,0 +1,6 @@
>> +ld 1
>> +libc 1
>> +libtracemod2.so 1
>> +libtracemod3.so 1
>> +libtracemod4.so 1
>> +libtracemod5.so 0
>
> OK, since libtracemod4 is also in path.
>
>> diff --git a/elf/tst-trace5.exp b/elf/tst-trace5.exp
>> new file mode 100644
>> index 0000000000..5d7d953726
>> --- /dev/null
>> +++ b/elf/tst-trace5.exp
>> @@ -0,0 +1,6 @@
>> +ld 1
>> +libc 1
>> +libtracemod2.so 1
>> +libtracemod3.so 1
>> +libtracemod4.so 1
>> +libtracemod5.so 1
>
> OK, since libtracemod5 is also in path.
>
>> diff --git a/scripts/tst-ld-trace.py b/scripts/tst-ld-trace.py
>> new file mode 100755
>> index 0000000000..f5a4028003
>> --- /dev/null
>> +++ b/scripts/tst-ld-trace.py
>> @@ -0,0 +1,108 @@
>> +#!/usr/bin/python3
>> +# Dump the output of LD_TRACE_LOADED_OBJECTS in architecture neutral format.
>> +# Copyright (C) 2022 Free Software Foundation, Inc.
>> +# Copyright The GNU Toolchain Authors.
>> +# 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
>> +# <https://www.gnu.org/licenses/>.
>> +
>> +import argparse
>> +import os
>> +import subprocess
>> +import sys
>> +
>> +try:
>> + subprocess.run
>> +except:
>> + class _CompletedProcess:
>> + def __init__(self, args, returncode, stdout=None, stderr=None):
>> + self.args = args
>> + self.returncode = returncode
>> + self.stdout = stdout
>> + self.stderr = stderr
>> +
>> + def _run(*popenargs, input=None, timeout=None, check=False, **kwargs):
>> + assert(timeout is None)
>> + with subprocess.Popen(*popenargs, **kwargs) as process:
>> + try:
>> + stdout, stderr = process.communicate(input)
>> + except:
>> + process.kill()
>> + process.wait()
>> + raise
>> + returncode = process.poll()
>> + if check and returncode:
>> + raise subprocess.CalledProcessError(returncode, popenargs)
>> + return _CompletedProcess(popenargs, returncode, stdout, stderr)
>> +
>> + subprocess.run = _run
>> +
>> +def is_vdso(lib):
>> + return lib.startswith('linux-gate') or lib.startswith('linux-vdso')
>
> OK.
>
>> +
>> +
>> +def parse_trace(cmd, fref):
>> + new_env = os.environ.copy()
>> + new_env['LD_TRACE_LOADED_OBJECTS'] = '1'
>> + trace_out = subprocess.run(cmd, stdout=subprocess.PIPE, check=True,
>> + universal_newlines=True, env=new_env).stdout
>> + trace = []
>> + for line in trace_out.splitlines():
>> + line = line.strip()
>> + if is_vdso(line):
>> + continue
>> + fields = line.split('=>' if '=>' in line else ' ')
>> + lib = os.path.basename(fields[0].strip())
>> + if lib.startswith('ld'):
>> + lib = 'ld'
>> + elif lib.startswith('libc'):
>> + lib = 'libc'
>> + found = 1 if fields[1].strip() != 'not found' else 0
>> + trace += ['{} {}'.format(lib, found)]
>> + trace = sorted(trace)
>> +
>> + reference = sorted(line.replace('\n','') for line in fref.readlines())
>> +
>> + ret = 0 if trace == reference else 1
>> + if ret != 0:
>> + for i in reference:
>> + if i not in trace:
>> + print("Only in {}: {}".format(fref.name, i))
>> + for i in trace:
>> + if i not in reference:
>> + print("Only in trace: {}".format(i))
>> +
>> + sys.exit(ret)
>
> OK.
>
>> +
>> +
>> +def get_parser():
>> + parser = argparse.ArgumentParser(description=__doc__)
>> + parser.add_argument('command',
>> + help='comand to run')
>> + parser.add_argument('reference',
>> + help='reference file to compare')
>> + return parser
>> +
>
> OK.
>
>> +
>> +def main(argv):
>> + parser = get_parser()
>> + opts = parser.parse_args(argv)
>> + with open(opts.reference, 'r') as fref:
>> + # Remove the initial 'env' command.
>> + parse_trace(opts.command.split()[1:], fref)
>> +
>> +
>> +if __name__ == '__main__':
>> + main(sys.argv[1:])
>
> OK.
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2022-04-26 19:29 UTC | newest]
Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2022-03-04 17:12 [PATCH v5] elf: Fix DFS sorting algorithm for LD_TRACE_LOADED_OBJECTS with missing libraries (BZ #28868) Adhemerval Zanella
2022-04-26 18:43 ` Siddhesh Poyarekar
2022-04-26 19:29 ` Adhemerval Zanella
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).