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-rw-r--r--NEWS4
-rw-r--r--elf/Makefile11
-rw-r--r--elf/dl-main.h2
-rw-r--r--elf/dl-tunables.c43
-rw-r--r--elf/dl-tunables.h2
-rw-r--r--elf/dl-usage.c7
-rw-r--r--elf/rtld.c19
-rw-r--r--elf/tst-rtld-list-tunables.exp14
-rwxr-xr-xelf/tst-rtld-list-tunables.sh34
-rw-r--r--manual/tunables.texi38
10 files changed, 172 insertions, 2 deletions
diff --git a/NEWS b/NEWS
index face78c..d121f7d 100644
--- a/NEWS
+++ b/NEWS
@@ -9,6 +9,10 @@ Version 2.33
Major new features:
+* The dynamic linker accepts the --list-tunables argument which prints
+ all the supported tunables. This option is disable if glibc is
+ configured with tunables disabled (--enable-tunables=no).
+
* The dynamic linker accepts the --argv0 argument and provides opportunity
to change argv[0] string.
diff --git a/elf/Makefile b/elf/Makefile
index c41d116..5e7f938 100644
--- a/elf/Makefile
+++ b/elf/Makefile
@@ -45,6 +45,10 @@ dl-routines += dl-tunables
tunables-type = $(addprefix TUNABLES_FRONTEND_,$(have-tunables))
CPPFLAGS-dl-tunables.c += -DTUNABLES_FRONTEND=$(tunables-type)
+ifeq (yesyes,$(build-shared)$(run-built-tests))
+tests-special += $(objpfx)list-tunables.out
+endif
+
# Make sure that the compiler does not insert any library calls in tunables
# code paths.
ifeq (yes,$(have-loop-to-function))
@@ -1896,3 +1900,10 @@ $(objpfx)tst-glibc-hwcaps-mask.out: \
# Generic dependency for sysdeps implementation of
# tst-glibc-hwcaps-cache.
$(objpfx)tst-glibc-hwcaps-cache.out: $(objpfx)tst-glibc-hwcaps
+
+$(objpfx)list-tunables.out: tst-rtld-list-tunables.sh $(objpfx)ld.so
+ $(SHELL) $< $(objpfx)ld.so '$(test-wrapper-env)' \
+ '$(run_program_env)' > $(objpfx)/tst-rtld-list-tunables.out
+ cmp tst-rtld-list-tunables.exp \
+ $(objpfx)/tst-rtld-list-tunables.out > $@; \
+ $(evaluate-test)
diff --git a/elf/dl-main.h b/elf/dl-main.h
index 0bccab1..3a5e13c 100644
--- a/elf/dl-main.h
+++ b/elf/dl-main.h
@@ -63,7 +63,7 @@ struct audit_list
enum rtld_mode
{
rtld_mode_normal, rtld_mode_list, rtld_mode_verify, rtld_mode_trace,
- rtld_mode_help,
+ rtld_mode_list_tunables, rtld_mode_help,
};
/* Aggregated state information extracted from environment variables
diff --git a/elf/dl-tunables.c b/elf/dl-tunables.c
index 9b4d737..33be00e 100644
--- a/elf/dl-tunables.c
+++ b/elf/dl-tunables.c
@@ -26,6 +26,7 @@
#include <sysdep.h>
#include <fcntl.h>
#include <ldsodefs.h>
+#include <array_length.h>
#define TUNABLES_INTERNAL 1
#include "dl-tunables.h"
@@ -398,6 +399,48 @@ __tunables_init (char **envp)
}
}
+void
+__tunables_print (void)
+{
+ for (int i = 0; i < array_length (tunable_list); i++)
+ {
+ const tunable_t *cur = &tunable_list[i];
+ if (cur->type.type_code == TUNABLE_TYPE_STRING
+ && cur->val.strval == NULL)
+ _dl_printf ("%s:\n", cur->name);
+ else
+ {
+ _dl_printf ("%s: ", cur->name);
+ switch (cur->type.type_code)
+ {
+ case TUNABLE_TYPE_INT_32:
+ _dl_printf ("%d (min: %d, max: %d)\n",
+ (int) cur->val.numval,
+ (int) cur->type.min,
+ (int) cur->type.max);
+ break;
+ case TUNABLE_TYPE_UINT_64:
+ _dl_printf ("0x%lx (min: 0x%lx, max: 0x%lx)\n",
+ (long int) cur->val.numval,
+ (long int) cur->type.min,
+ (long int) cur->type.max);
+ break;
+ case TUNABLE_TYPE_SIZE_T:
+ _dl_printf ("0x%Zx (min: 0x%Zx, max: 0x%Zx)\n",
+ (size_t) cur->val.numval,
+ (size_t) cur->type.min,
+ (size_t) cur->type.max);
+ break;
+ case TUNABLE_TYPE_STRING:
+ _dl_printf ("%s\n", cur->val.strval);
+ break;
+ default:
+ __builtin_unreachable ();
+ }
+ }
+ }
+}
+
/* Set the tunable value. This is called by the module that the tunable exists
in. */
void
diff --git a/elf/dl-tunables.h b/elf/dl-tunables.h
index 518342a..dfa16c1 100644
--- a/elf/dl-tunables.h
+++ b/elf/dl-tunables.h
@@ -69,9 +69,11 @@ typedef struct _tunable tunable_t;
# include "dl-tunable-list.h"
extern void __tunables_init (char **);
+extern void __tunables_print (void);
extern void __tunable_get_val (tunable_id_t, void *, tunable_callback_t);
extern void __tunable_set_val (tunable_id_t, void *, void *, void *);
rtld_hidden_proto (__tunables_init)
+rtld_hidden_proto (__tunables_print)
rtld_hidden_proto (__tunable_get_val)
rtld_hidden_proto (__tunable_set_val)
diff --git a/elf/dl-usage.c b/elf/dl-usage.c
index 907f068..6e26818 100644
--- a/elf/dl-usage.c
+++ b/elf/dl-usage.c
@@ -255,7 +255,12 @@ setting environment variables (which would be inherited by subprocesses).\n\
in LIST\n\
--audit LIST use objects named in LIST as auditors\n\
--preload LIST preload objects named in LIST\n\
- --argv0 STRING set argv[0] to STRING before running\n\
+ --argv0 STRING set argv[0] to STRING before running\n"
+#if HAVE_TUNABLES
+"\
+ --list-tunables list all tunables with minimum and maximum values\n"
+#endif
+"\
--help display this help and exit\n\
--version output version information and exit\n\
\n\
diff --git a/elf/rtld.c b/elf/rtld.c
index 8d9add9..596b6ac 100644
--- a/elf/rtld.c
+++ b/elf/rtld.c
@@ -50,6 +50,7 @@
#include <dl-main.h>
#include <list.h>
#include <gnu/lib-names.h>
+#include <dl-tunables.h>
#include <assert.h>
@@ -1276,6 +1277,16 @@ dl_main (const ElfW(Phdr) *phdr,
_dl_argc -= 2;
_dl_argv += 2;
}
+#if HAVE_TUNABLES
+ else if (! strcmp (_dl_argv[1], "--list-tunables"))
+ {
+ state.mode = rtld_mode_list_tunables;
+
+ ++_dl_skip_args;
+ --_dl_argc;
+ ++_dl_argv;
+ }
+#endif
else if (strcmp (_dl_argv[1], "--help") == 0)
{
state.mode = rtld_mode_help;
@@ -1296,6 +1307,14 @@ dl_main (const ElfW(Phdr) *phdr,
else
break;
+#if HAVE_TUNABLES
+ if (__glibc_unlikely (state.mode == rtld_mode_list_tunables))
+ {
+ __tunables_print ();
+ _exit (0);
+ }
+#endif
+
/* If we have no further argument the program was called incorrectly.
Grant the user some education. */
if (_dl_argc < 2)
diff --git a/elf/tst-rtld-list-tunables.exp b/elf/tst-rtld-list-tunables.exp
new file mode 100644
index 0000000..4f3f7ee
--- /dev/null
+++ b/elf/tst-rtld-list-tunables.exp
@@ -0,0 +1,14 @@
+glibc.malloc.arena_max: 0x0 (min: 0x1, max: 0x[f]+)
+glibc.malloc.arena_test: 0x0 (min: 0x1, max: 0x[f]+)
+glibc.malloc.check: 0 (min: 0, max: 3)
+glibc.malloc.mmap_max: 0 (min: -2147483648, max: 2147483647)
+glibc.malloc.mmap_threshold: 0x0 (min: 0x0, max: 0x[f]+)
+glibc.malloc.mxfast: 0x0 (min: 0x0, max: 0x[f]+)
+glibc.malloc.perturb: 0 (min: 0, max: 255)
+glibc.malloc.tcache_count: 0x0 (min: 0x0, max: 0x[f]+)
+glibc.malloc.tcache_max: 0x0 (min: 0x0, max: 0x[f]+)
+glibc.malloc.tcache_unsorted_limit: 0x0 (min: 0x0, max: 0x[f]+)
+glibc.malloc.top_pad: 0x0 (min: 0x0, max: 0x[f]+)
+glibc.malloc.trim_threshold: 0x0 (min: 0x0, max: 0x[f]+)
+glibc.rtld.nns: 0x4 (min: 0x1, max: 0x10)
+glibc.rtld.optional_static_tls: 0x200 (min: 0x0, max: 0x[f]+)
diff --git a/elf/tst-rtld-list-tunables.sh b/elf/tst-rtld-list-tunables.sh
new file mode 100755
index 0000000..e7bbdde
--- /dev/null
+++ b/elf/tst-rtld-list-tunables.sh
@@ -0,0 +1,34 @@
+#!/bin/sh
+# Test for --list-tunables option ld.so.
+# Copyright (C) 2021 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
+# <https://www.gnu.org/licenses/>.
+
+set -e
+
+rtld=$1
+test_wrapper_env=$2
+run_program_env=$3
+
+LC_ALL=C
+export LC_ALL
+
+${test_wrapper_env} \
+${run_program_env} \
+$rtld --list-tunables \
+| sort -u \
+| egrep "(rtld|malloc)" \
+| sed -e "s/0xf\+/0x[f]+/"
diff --git a/manual/tunables.texi b/manual/tunables.texi
index 1bbdc88..1b746c0 100644
--- a/manual/tunables.texi
+++ b/manual/tunables.texi
@@ -28,6 +28,44 @@ Finally, the set of tunables available may vary between distributions as
the tunables feature allows distributions to add their own tunables under
their own namespace.
+Passing @option{--list-tunables} to the dynamic loader to print all
+tunables with minimum and maximum values:
+
+@example
+$ /lib64/ld-linux-x86-64.so.2 --list-tunables
+glibc.rtld.nns: 0x4 (min: 0x1, max: 0x10)
+glibc.elision.skip_lock_after_retries: 3 (min: -2147483648, max: 2147483647)
+glibc.malloc.trim_threshold: 0x0 (min: 0x0, max: 0xffffffffffffffff)
+glibc.malloc.perturb: 0 (min: 0, max: 255)
+glibc.cpu.x86_shared_cache_size: 0x100000 (min: 0x0, max: 0xffffffffffffffff)
+glibc.mem.tagging: 0 (min: 0, max: 255)
+glibc.elision.tries: 3 (min: -2147483648, max: 2147483647)
+glibc.elision.enable: 0 (min: 0, max: 1)
+glibc.cpu.x86_rep_movsb_threshold: 0x1000 (min: 0x100, max: 0xffffffffffffffff)
+glibc.malloc.mxfast: 0x0 (min: 0x0, max: 0xffffffffffffffff)
+glibc.elision.skip_lock_busy: 3 (min: -2147483648, max: 2147483647)
+glibc.malloc.top_pad: 0x0 (min: 0x0, max: 0xffffffffffffffff)
+glibc.cpu.x86_rep_stosb_threshold: 0x800 (min: 0x1, max: 0xffffffffffffffff)
+glibc.cpu.x86_non_temporal_threshold: 0xc0000 (min: 0x0, max: 0xffffffffffffffff)
+glibc.cpu.x86_shstk:
+glibc.cpu.hwcap_mask: 0x6 (min: 0x0, max: 0xffffffffffffffff)
+glibc.malloc.mmap_max: 0 (min: -2147483648, max: 2147483647)
+glibc.elision.skip_trylock_internal_abort: 3 (min: -2147483648, max: 2147483647)
+glibc.malloc.tcache_unsorted_limit: 0x0 (min: 0x0, max: 0xffffffffffffffff)
+glibc.cpu.x86_ibt:
+glibc.cpu.hwcaps:
+glibc.elision.skip_lock_internal_abort: 3 (min: -2147483648, max: 2147483647)
+glibc.malloc.arena_max: 0x0 (min: 0x1, max: 0xffffffffffffffff)
+glibc.malloc.mmap_threshold: 0x0 (min: 0x0, max: 0xffffffffffffffff)
+glibc.cpu.x86_data_cache_size: 0x8000 (min: 0x0, max: 0xffffffffffffffff)
+glibc.malloc.tcache_count: 0x0 (min: 0x0, max: 0xffffffffffffffff)
+glibc.malloc.arena_test: 0x0 (min: 0x1, max: 0xffffffffffffffff)
+glibc.pthread.mutex_spin_count: 100 (min: 0, max: 32767)
+glibc.rtld.optional_static_tls: 0x200 (min: 0x0, max: 0xffffffffffffffff)
+glibc.malloc.tcache_max: 0x0 (min: 0x0, max: 0xffffffffffffffff)
+glibc.malloc.check: 0 (min: 0, max: 3)
+@end example
+
@menu
* Tunable names:: The structure of a tunable name
* Memory Allocation Tunables:: Tunables in the memory allocation subsystem