diff options
| -rw-r--r-- | ChangeLog | 41 | ||||
| -rw-r--r-- | INSTALL | 5 | ||||
| -rw-r--r-- | Makeconfig | 16 | ||||
| -rw-r--r-- | README.tunables | 85 | ||||
| -rw-r--r-- | config.h.in | 3 | ||||
| -rw-r--r-- | config.make.in | 1 | ||||
| -rwxr-xr-x | configure | 16 | ||||
| -rw-r--r-- | configure.ac | 10 | ||||
| -rw-r--r-- | csu/init-first.c | 2 | ||||
| -rw-r--r-- | csu/libc-start.c | 8 | ||||
| -rw-r--r-- | elf/Makefile | 5 | ||||
| -rw-r--r-- | elf/Versions | 3 | ||||
| -rw-r--r-- | elf/dl-support.c | 2 | ||||
| -rw-r--r-- | elf/dl-sysdep.c | 4 | ||||
| -rw-r--r-- | elf/dl-tunable-types.h | 46 | ||||
| -rw-r--r-- | elf/dl-tunables.c | 320 | ||||
| -rw-r--r-- | elf/dl-tunables.h | 88 | ||||
| -rw-r--r-- | elf/dl-tunables.list | 69 | ||||
| -rw-r--r-- | elf/rtld.c | 2 | ||||
| -rw-r--r-- | malloc/Makefile | 2 | ||||
| -rw-r--r-- | malloc/arena.c | 54 | ||||
| -rw-r--r-- | malloc/tst-malloc-usable-static.c | 1 | ||||
| -rw-r--r-- | manual/install.texi | 5 | ||||
| -rw-r--r-- | scripts/gen-tunables.awk | 157 | ||||
| -rw-r--r-- | sysdeps/mach/hurd/dl-sysdep.c | 4 |
25 files changed, 947 insertions, 2 deletions
@@ -1,3 +1,44 @@ +2016-12-31 Siddhesh Poyarekar <siddhesh@sourceware.org> + + * manual/install.texi: Add --enable-tunables option. + * INSTALL: Regenerate. + * README.tunables: New file. + * Makeconfig (CPPFLAGS): Define TOP_NAMESPACE. + (before-compile): Generate dl-tunable-list.h early. + * config.h.in: Add HAVE_TUNABLES. + * config.make.in: Add have-tunables. + * configure.ac: Add --enable-tunables option. + * configure: Regenerate. + * csu/init-first.c (__libc_init_first): Move + __libc_init_secure earlier... + * csu/init-first.c (LIBC_START_MAIN):... to here. + Include dl-tunables.h, libc-internal.h. + (LIBC_START_MAIN) [!SHARED]: Initialize tunables for static + binaries. + * elf/Makefile (dl-routines): Add dl-tunables. + * elf/Versions (ld): Add __tunable_set_val to GLIBC_PRIVATE + namespace. + * elf/dl-support (_dl_nondynamic_init): Unset MALLOC_CHECK_ + only when !HAVE_TUNABLES. + * elf/rtld.c (process_envvars): Likewise. + * elf/dl-sysdep.c [HAVE_TUNABLES]: Include dl-tunables.h + (_dl_sysdep_start): Call __tunables_init. + * elf/dl-tunable-types.h: New file. + * elf/dl-tunables.c: New file. + * elf/dl-tunables.h: New file. + * elf/dl-tunables.list: New file. + * malloc/tst-malloc-usable-static.c: New test case. + * malloc/Makefile (tests-static): Add it. + * malloc/arena.c [HAVE_TUNABLES]: Include dl-tunables.h. + Define TUNABLE_NAMESPACE. + (DL_TUNABLE_CALLBACK (set_mallopt_check)): New function. + (DL_TUNABLE_CALLBACK_FNDECL): New macro. Use it to define + callback functions. + (ptmalloc_init): Set tunable values. + * scripts/gen-tunables.awk: New file. + * sysdeps/mach/hurd/dl-sysdep.c: Include dl-tunables.h. + (_dl_sysdep_start): Call __tunables_init. + 2016-12-31 Florian Weimer <fweimer@redhat.com> * resolv/resolv.h (RES_BLAST): Deprecate. @@ -169,6 +169,11 @@ will be used, and CFLAGS sets optimization options for the compiler. By default for x86_64, the GNU C Library is built with the vector math library. Use this option to disable the vector math library. +'--enable-tunables' + Tunables support allows additional library parameters to be + customized at runtime. This is an experimental feature and affects + startup time and is thus disabled by default. + '--build=BUILD-SYSTEM' '--host=HOST-SYSTEM' These options are for cross-compiling. If you specify both options diff --git a/Makeconfig b/Makeconfig index 0158eaa76e..b173e4cc08 100644 --- a/Makeconfig +++ b/Makeconfig @@ -934,6 +934,11 @@ CPPFLAGS = $(config-extra-cppflags) $(CPPUNDEFS) $(CPPFLAGS-config) \ $(foreach lib,$(libof-$(basename $(@F))) \ $(libof-$(<F)) $(libof-$(@F)),$(CPPFLAGS-$(lib))) \ $(CPPFLAGS-$(<F)) $(CPPFLAGS-$(@F)) $(CPPFLAGS-$(basename $(@F))) + +ifeq (yes,$(have-tunables)) +CPPFLAGS += -DTOP_NAMESPACE=glibc +endif + override CFLAGS = -std=gnu11 -fgnu89-inline $(config-extra-cflags) \ $(filter-out %frame-pointer,$(+cflags)) $(+gccwarn-c) \ $(sysdep-CFLAGS) $(CFLAGS-$(suffix $@)) $(CFLAGS-$(<F)) \ @@ -1108,6 +1113,17 @@ $(common-objpfx)libc-modules.stmp: $(..)scripts/gen-libc-modules.awk \ endif +# Build the tunables list header early since it could be used by any module in +# glibc. +ifeq (yes,$(have-tunables)) +before-compile += $(common-objpfx)dl-tunable-list.h + +$(common-objpfx)dl-tunable-list.h: $(..)scripts/gen-tunables.awk \ + $(..)elf/dl-tunables.list + $(AWK) -f $^ > $@.tmp + mv $@.tmp $@ +endif + common-generated += libc-modules.h libc-modules.stmp # The name under which the run-time dynamic linker is installed. diff --git a/README.tunables b/README.tunables new file mode 100644 index 0000000000..df74f3b24b --- /dev/null +++ b/README.tunables @@ -0,0 +1,85 @@ + TUNABLE FRAMEWORK + ================= + +Tunables is a feature in the GNU C Library that allows application authors and +distribution maintainers to alter the runtime library behaviour to match their +workload. + +The tunable framework allows modules within glibc to register variables that +may be tweaked through an environment variable. It aims to enforce a strict +namespace rule to bring consistency to naming of these tunable environment +variables across the project. This document is a guide for glibc developers to +add tunables to the framework. + +ADDING A NEW TUNABLE +-------------------- + +The TOP_NAMESPACE macro is defined by default as 'glibc'. If distributions +intend to add their own tunables, they should do so in a different top +namespace by overriding the TOP_NAMESPACE macro for that tunable. Downstream +implementations are discouraged from using the 'glibc' top namespace for +tunables they don't already have consensus to push upstream. + +There are two steps to adding a tunable: + +1. Add a tunable ID: + +Modules that wish to use the tunables interface must define the +TUNABLE_NAMESPACE macro. Following this, for each tunable you want to +add, make an entry in elf/dl-tunables.list. The format of the file is as +follows: + +TOP_NAMESPACE { + NAMESPACE1 { + TUNABLE1 { + # tunable attributes, one per line + } + # A tunable with default attributes, i.e. string variable. + TUNABLE2 + TUNABLE3 { + # its attributes + } + } + NAMESPACE2 { + ... + } +} + +The list of allowed attributes are: + +- type: Data type. Defaults to STRING. Allowed types are: + INT_32, SIZE_T and STRING. + +- minval: Optional minimum acceptable value. For a string type + this is the minimum length of the value. + +- maxval: Optional maximum acceptable value. For a string type + this is the maximum length of the value. + +- env_alias: An alias environment variable + +- is_secure: Specify whether the tunable should be read for setuid + binaries. True allows the tunable to be read for + setuid binaries while false disables it. Note that + even if this is set as true and the value is read, it + may not be used if it does not validate against the + acceptable values or is not considered safe by the + module. + +2. Call either the TUNABLE_SET_VALUE and pass into it the tunable name and a + pointer to the variable that should be set with the tunable value. + If additional work needs to be done after setting the value, use the + TUNABLE_SET_VALUE_WITH_CALLBACK instead and additionally pass a pointer to + the function that should be called if the tunable value has been set. + +FUTURE WORK +----------- + +The framework currently only allows a one-time initialization of variables +through environment variables and in some cases, modification of variables via +an API call. A future goals for this project include: + +- Setting system-wide and user-wide defaults for tunables through some + mechanism like a configuration file. + +- Allow tweaking of some tunables at runtime diff --git a/config.h.in b/config.h.in index 82f95a6dbd..7bfe923c06 100644 --- a/config.h.in +++ b/config.h.in @@ -256,4 +256,7 @@ /* PowerPC32 uses fctidz for floating point to long long conversions. */ #define HAVE_PPC_FCTIDZ 0 +/* Build glibc with tunables support. */ +#define HAVE_TUNABLES 0 + #endif diff --git a/config.make.in b/config.make.in index 4422025e59..2f8dae213d 100644 --- a/config.make.in +++ b/config.make.in @@ -96,6 +96,7 @@ use-nscd = @use_nscd@ build-hardcoded-path-in-tests= @hardcoded_path_in_tests@ build-pt-chown = @build_pt_chown@ enable-lock-elision = @enable_lock_elision@ +have-tunables = @have_tunables@ # Build tools. CC = @CC@ @@ -666,6 +666,7 @@ libc_cv_ssp base_machine add_on_subdirs add_ons +have_tunables build_pt_chown build_nscd link_obsolete_rpc @@ -782,6 +783,7 @@ enable_systemtap enable_build_nscd enable_nscd enable_pt_chown +enable_tunables enable_mathvec with_cpu ' @@ -1452,6 +1454,7 @@ Optional Features: --disable-build-nscd disable building and installing the nscd daemon --disable-nscd library functions will not contact the nscd daemon --enable-pt_chown Enable building and installing pt_chown + --enable-tunables Enable tunables support --enable-mathvec Enable building and installing mathvec [default depends on architecture] @@ -3698,6 +3701,19 @@ if test "$build_pt_chown" = yes; then fi +# Check whether --enable-tunables was given. +if test "${enable_tunables+set}" = set; then : + enableval=$enable_tunables; have_tunables=$enableval +else + have_tunables=no +fi + + +if test "$have_tunables" = yes; then + $as_echo "#define HAVE_TUNABLES 1" >>confdefs.h + +fi + # The abi-tags file uses a fairly simplistic model for name recognition that # can't distinguish i486-pc-linux-gnu fully from i486-pc-gnu. So we mutate a # $host_os of `gnu*' here to be `gnu-gnu*' just so that it can tell. diff --git a/configure.ac b/configure.ac index 2782bfaf08..22f5cab200 100644 --- a/configure.ac +++ b/configure.ac @@ -421,6 +421,16 @@ if test "$build_pt_chown" = yes; then AC_DEFINE(HAVE_PT_CHOWN) fi +AC_ARG_ENABLE([tunables], + [AS_HELP_STRING([--enable-tunables], + [Enable tunables support])], + [have_tunables=$enableval], + [have_tunables=no]) +AC_SUBST(have_tunables) +if test "$have_tunables" = yes; then + AC_DEFINE(HAVE_TUNABLES) +fi + # The abi-tags file uses a fairly simplistic model for name recognition that # can't distinguish i486-pc-linux-gnu fully from i486-pc-gnu. So we mutate a # $host_os of `gnu*' here to be `gnu-gnu*' just so that it can tell. diff --git a/csu/init-first.c b/csu/init-first.c index 77c6e1cb9e..465f25b722 100644 --- a/csu/init-first.c +++ b/csu/init-first.c @@ -72,8 +72,6 @@ _init (int argc, char **argv, char **envp) __environ = envp; #ifndef SHARED - __libc_init_secure (); - /* First the initialization which normally would be done by the dynamic linker. */ _dl_non_dynamic_init (); diff --git a/csu/libc-start.c b/csu/libc-start.c index cc59073abe..15db9b4684 100644 --- a/csu/libc-start.c +++ b/csu/libc-start.c @@ -21,6 +21,9 @@ #include <unistd.h> #include <ldsodefs.h> #include <exit-thread.h> +#include <libc-internal.h> + +#include <elf/dl-tunables.h> extern void __libc_init_first (int argc, char **argv, char **envp); @@ -174,6 +177,11 @@ LIBC_START_MAIN (int (*main) (int, char **, char ** MAIN_AUXVEC_DECL), } } + /* Initialize very early so that tunables can use it. */ + __libc_init_secure (); + + __tunables_init (__environ); + /* Perform IREL{,A} relocations. */ apply_irel (); diff --git a/elf/Makefile b/elf/Makefile index 8a2ce02cd5..de28d99224 100644 --- a/elf/Makefile +++ b/elf/Makefile @@ -35,6 +35,11 @@ dl-routines = $(addprefix dl-,load lookup object reloc deps hwcaps \ ifeq (yes,$(use-ldconfig)) dl-routines += dl-cache endif + +ifeq (yes,$(have-tunables)) +dl-routines += dl-tunables +endif + all-dl-routines = $(dl-routines) $(sysdep-dl-routines) # But they are absent from the shared libc, because that code is in ld.so. elide-routines.os = $(all-dl-routines) dl-support enbl-secure dl-origin \ diff --git a/elf/Versions b/elf/Versions index 3d57e36fd2..6abe9db8bd 100644 --- a/elf/Versions +++ b/elf/Versions @@ -70,5 +70,8 @@ ld { # Internal error handling support. Interposed by libc.so. _dl_signal_error; _dl_catch_error; + + # Set value of a tunable. + __tunable_set_val; } } diff --git a/elf/dl-support.c b/elf/dl-support.c index c30194c7b7..d350d6d0d0 100644 --- a/elf/dl-support.c +++ b/elf/dl-support.c @@ -354,8 +354,10 @@ _dl_non_dynamic_init (void) cp = (const char *) __rawmemchr (cp, '\0') + 1; } +#if !HAVE_TUNABLES if (__access ("/etc/suid-debug", F_OK) != 0) __unsetenv ("MALLOC_CHECK_"); +#endif } #ifdef DL_PLATFORM_INIT diff --git a/elf/dl-sysdep.c b/elf/dl-sysdep.c index eaa71556d2..4283767fe0 100644 --- a/elf/dl-sysdep.c +++ b/elf/dl-sysdep.c @@ -44,6 +44,8 @@ #include <hp-timing.h> #include <tls.h> +#include <dl-tunables.h> + extern char **_environ attribute_hidden; extern char _end[] attribute_hidden; @@ -219,6 +221,8 @@ _dl_sysdep_start (void **start_argptr, } #endif + __tunables_init (_environ); + #ifdef DL_SYSDEP_INIT DL_SYSDEP_INIT; #endif diff --git a/elf/dl-tunable-types.h b/elf/dl-tunable-types.h new file mode 100644 index 0000000000..d1591b6efb --- /dev/null +++ b/elf/dl-tunable-types.h @@ -0,0 +1,46 @@ +/* Tunable type information. + + Copyright (C) 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/>. */ + +#ifndef _TUNABLE_TYPES_H_ +# define _TUNABLE_TYPES_H_ +#include <stddef.h> + +typedef void (*tunable_callback_t) (void *); + +typedef enum +{ + TUNABLE_TYPE_INT_32, + TUNABLE_TYPE_SIZE_T, + TUNABLE_TYPE_STRING +} tunable_type_code_t; + +typedef struct +{ + tunable_type_code_t type_code; + int64_t min; + int64_t max; +} tunable_type_t; + +typedef union +{ + int64_t numval; + const char *strval; +} tunable_val_t; + +#endif diff --git a/elf/dl-tunables.c b/elf/dl-tunables.c new file mode 100644 index 0000000000..472747b3da --- /dev/null +++ b/elf/dl-tunables.c @@ -0,0 +1,320 @@ +/* The tunable framework. See the README.tunables to know how to use the + tunable in a glibc module. + + Copyright (C) 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/>. */ + +#include <stdint.h> +#include <stdbool.h> +#include <unistd.h> +#include <stdlib.h> +#include <libc-internal.h> +#include <sysdep.h> +#include <fcntl.h> +#include <ldsodefs.h> + +#define TUNABLES_INTERNAL 1 +#include "dl-tunables.h" + +/* Compare environment names, bounded by the name hardcoded in glibc. */ +static bool +is_name (const char *orig, const char *envname) +{ + for (;*orig != '\0' && *envname != '\0'; envname++, orig++) + if (*orig != *envname) + break; + + /* The ENVNAME is immediately followed by a value. */ + if (*orig == '\0' && *envname == '=') + return true; + else + return false; +} + +static char ** +get_next_env (char **envp, char **name, size_t *namelen, char **val) +{ + while (envp != NULL && *envp != NULL) + { + char *envline = *envp; + int len = 0; + + while (envline[len] != '\0' && envline[len] != '=') + len++; + + /* Just the name and no value, go to the next one. */ + if (envline[len] == '\0') + continue; + + *name = envline; + *namelen = len; + *val = &envline[len + 1]; + + return ++envp; + } + + return NULL; +} + +static int +tunables_unsetenv (char **ep, const char *name) +{ + while (*ep != NULL) + { + size_t cnt = 0; + + while ((*ep)[cnt] == name[cnt] && name[cnt] != '\0') + ++cnt; + + if (name[cnt] == '\0' && (*ep)[cnt] == '=') + { + /* Found it. Remove this pointer by moving later ones to + the front. */ + char **dp = ep; + + do + dp[0] = dp[1]; + while (*dp++); + /* Continue the loop in case NAME appears again. */ + } + else + ++ep; + } + + return 0; +} + +/* A stripped down strtoul-like implementation for very early use. It does not + set errno if the result is outside bounds because it gets called before + errno may have been set up. */ +static unsigned long int +tunables_strtoul (const char *nptr) +{ + unsigned long int result = 0; + long int sign = 1; + unsigned max_digit; + + while (*nptr == ' ' || *nptr == '\t') + ++nptr; + + if (*nptr == '-') + { + sign = -1; + ++nptr; + } + else if (*nptr == '+') + ++nptr; + + if (*nptr < '0' || *nptr > '9') + return 0UL; + + int base = 10; + |