diff options
| -rw-r--r-- | ChangeLog | 20 | ||||
| -rw-r--r-- | README.tunables | 69 | ||||
| -rw-r--r-- | elf/Versions | 2 | ||||
| -rw-r--r-- | elf/dl-tunables.c | 58 | ||||
| -rw-r--r-- | elf/dl-tunables.h | 53 | ||||
| -rw-r--r-- | malloc/arena.c | 36 |
6 files changed, 168 insertions, 70 deletions
@@ -1,3 +1,23 @@ +2017-06-07 Siddhesh Poyarekar <siddhesh@sourceware.org> + + * elf/Versions (__tunable_set_val): Rename to __tunable_get_val. + * elf/dl-tunables.c: Likewise. + (do_tunable_update_val): New function. + (__tunable_set_val): New function. + (__tunable_get_val): Call CB only if the tunable was externally + initialized. + (tunables_strtoul): Replace strval with initialized. + * elf/dl-tunables.h (strval): Replace with a bool initialized. + (TUNABLE_ENUM_NAME, TUNABLE_ENUM_NAME1): Adjust names to + prevent collision. + (__tunable_set_val): New function. + (TUNABLE_GET, TUNABLE_GET_FULL): New macros. + (TUNABLE_SET, TUNABLE_SET_FULL): Likewise. + (TUNABLE_SET_VAL): Remove. + (TUNABLE_SET_VAL_WITH_CALLBACK): Likewise. + * README.tunables: Document the new macros. + * malloc/arena.c (ptmalloc_init): Adjust. + 2017-06-06 H.J. Lu <hongjiu.lu@intel.com> * sysdeps/x86_64/multiarch/Makefile (sysdep_routines): Add diff --git a/README.tunables b/README.tunables index 0e9b0d7..3967679 100644 --- a/README.tunables +++ b/README.tunables @@ -20,14 +20,12 @@ 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: +There are three steps to adding a tunable: -1. Add a tunable ID: +1. Add a tunable to the list and fully specify its properties: -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: +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 { @@ -69,11 +67,60 @@ The list of allowed attributes are: non-AT_SECURE subprocesses. NONE: Read all the time. -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. +2. Use TUNABLE_GET/TUNABLE_SET to get and set tunables. + +3. OPTIONAL: If tunables in a namespace are being used multiple times within a + specific module, set the TUNABLE_NAMESPACE macro to reduce the amount of + typing. + +GETTING AND SETTING TUNABLES +---------------------------- + +When the TUNABLE_NAMESPACE macro is defined, one may get tunables in that +module using the TUNABLE_GET macro as follows: + + val = TUNABLE_GET (check, int32_t, TUNABLE_CALLBACK (check_callback)) + +where 'check' is the tunable name, 'int32_t' is the C type of the tunable and +'check_callback' is the function to call if the tunable got initialized to a +non-default value. The macro returns the value as type 'int32_t'. + +The callback function should be defined as follows: + + void + TUNABLE_CALLBACK (check_callback) (int32_t *valp) + { + ... + } + +where it can expect the tunable value to be passed in VALP. + +Tunables in the module can be updated using: + + TUNABLE_SET (check, int32_t, val) + +where 'check' is the tunable name, 'int32_t' is the C type of the tunable and +'val' is a value of same type. + +To get and set tunables in a different namespace from that module, use the full +form of the macros as follows: + + val = TUNABLE_GET_FULL (glibc, tune, hwcap_mask, uint64_t, NULL) + + TUNABLE_SET_FULL (glibc, tune, hwcap_mask, uint64_t, val) + +where 'glibc' is the top namespace, 'tune' is the tunable namespace and the +remaining arguments are the same as the short form macros. + +When TUNABLE_NAMESPACE is not defined in a module, TUNABLE_GET is equivalent to +TUNABLE_GET_FULL, so you will need to provide full namespace information for +both macros. Likewise for TUNABLE_SET and TUNABLE_SET_FULL. + +** IMPORTANT NOTE ** + +The tunable list is set as read-only after the dynamic linker relocates itself, +so setting tunable values must be limited only to tunables within the dynamic +linker, that too before relocation. FUTURE WORK ----------- diff --git a/elf/Versions b/elf/Versions index 6abe9db..c59facd 100644 --- a/elf/Versions +++ b/elf/Versions @@ -72,6 +72,6 @@ ld { _dl_signal_error; _dl_catch_error; # Set value of a tunable. - __tunable_set_val; + __tunable_get_val; } } diff --git a/elf/dl-tunables.c b/elf/dl-tunables.c index b6e6b3d..76e8c5c 100644 --- a/elf/dl-tunables.c +++ b/elf/dl-tunables.c @@ -184,19 +184,17 @@ tunables_strtoul (const char *nptr) if ((__type) (__val) >= min && (__type) (val) <= max) \ { \ (__cur)->val.numval = val; \ - (__cur)->strval = strval; \ + (__cur)->initialized = true; \ } \ }) -/* Validate range of the input value and initialize the tunable CUR if it looks - good. */ static void -tunable_initialize (tunable_t *cur, const char *strval) +do_tunable_update_val (tunable_t *cur, const void *valp) { uint64_t val; if (cur->type.type_code != TUNABLE_TYPE_STRING) - val = tunables_strtoul (strval); + val = *((int64_t *) valp); switch (cur->type.type_code) { @@ -217,7 +215,7 @@ tunable_initialize (tunable_t *cur, const char *strval) } case TUNABLE_TYPE_STRING: { - cur->val.strval = cur->strval = strval; + cur->val.strval = valp; break; } default: @@ -225,6 +223,35 @@ tunable_initialize (tunable_t *cur, const char *strval) } } +/* Validate range of the input value and initialize the tunable CUR if it looks + good. */ +static void +tunable_initialize (tunable_t *cur, const char *strval) +{ + uint64_t val; + const void *valp; + + if (cur->type.type_code != TUNABLE_TYPE_STRING) + { + val = tunables_strtoul (strval); + valp = &val; + } + else + { + cur->initialized = true; + valp = strval; + } + do_tunable_update_val (cur, valp); +} + +void +__tunable_set_val (tunable_id_t id, void *valp) +{ + tunable_t *cur = &tunable_list[id]; + + do_tunable_update_val (cur, valp); +} + #if TUNABLES_FRONTEND == TUNABLES_FRONTEND_valstring /* Parse the tunable string TUNESTR and adjust it to drop any tunables that may be unsafe for AT_SECURE processes so that it can be used as the new @@ -375,7 +402,7 @@ __tunables_init (char **envp) /* Skip over tunables that have either been set already or should be skipped. */ - if (cur->strval != NULL || cur->env_alias == NULL) + if (cur->initialized || cur->env_alias == NULL) continue; const char *name = cur->env_alias; @@ -426,20 +453,10 @@ __tunables_init (char **envp) /* Set the tunable value. This is called by the module that the tunable exists in. */ void -__tunable_set_val (tunable_id_t id, void *valp, tunable_callback_t callback) +__tunable_get_val (tunable_id_t id, void *valp, tunable_callback_t callback) { tunable_t *cur = &tunable_list[id]; - /* Don't do anything if our tunable was not set during initialization or if - it failed validation. */ - if (cur->strval == NULL) - return; - - /* Caller does not need the value, just call the callback with our tunable - value. */ - if (valp == NULL) - goto cb; - switch (cur->type.type_code) { case TUNABLE_TYPE_UINT_64: @@ -466,9 +483,8 @@ __tunable_set_val (tunable_id_t id, void *valp, tunable_callback_t callback) __builtin_unreachable (); } -cb: - if (callback) + if (cur->initialized && callback != NULL) callback (&cur->val); } -rtld_hidden_def (__tunable_set_val) +rtld_hidden_def (__tunable_get_val) diff --git a/elf/dl-tunables.h b/elf/dl-tunables.h index 20ee512..6c49dcb 100644 --- a/elf/dl-tunables.h +++ b/elf/dl-tunables.h @@ -39,8 +39,8 @@ struct _tunable const char *name; /* Internal name of the tunable. */ tunable_type_t type; /* Data type of the tunable. */ tunable_val_t val; /* The value. */ - const char *strval; /* The string containing the value, - points into envp. */ + bool initialized; /* Flag to indicate that the tunable is + initialized. */ tunable_seclevel_t security_level; /* Specify the security level for the tunable with respect to AT_SECURE programs. See description of @@ -61,37 +61,52 @@ typedef struct _tunable tunable_t; /* Full name for a tunable is top_ns.tunable_ns.id. */ # define TUNABLE_NAME_S(top,ns,id) #top "." #ns "." #id -# define TUNABLE_ENUM_NAME(top,ns,id) TUNABLE_ENUM_NAME1 (top,ns,id) -# define TUNABLE_ENUM_NAME1(top,ns,id) top ## _ ## ns ## _ ## id +# define TUNABLE_ENUM_NAME(__top,__ns,__id) TUNABLE_ENUM_NAME1 (__top,__ns,__id) +# define TUNABLE_ENUM_NAME1(__top,__ns,__id) __top ## _ ## __ns ## _ ## __id # include "dl-tunable-list.h" extern void __tunables_init (char **); -extern void __tunable_set_val (tunable_id_t, void *, tunable_callback_t); - +extern void __tunable_get_val (tunable_id_t, void *, tunable_callback_t); +extern void __tunable_set_val (tunable_id_t, void *); rtld_hidden_proto (__tunables_init) -rtld_hidden_proto (__tunable_set_val) +rtld_hidden_proto (__tunable_get_val) + +/* Define TUNABLE_GET and TUNABLE_SET in short form if TOP_NAMESPACE and + TUNABLE_NAMESPACE are defined. This is useful shorthand to get and set + tunables within a module. */ +#if defined TOP_NAMESPACE && defined TUNABLE_NAMESPACE +# define TUNABLE_GET(__id, __type, __cb) \ + TUNABLE_GET_FULL (TOP_NAMESPACE, TUNABLE_NAMESPACE, __id, __type, __cb) +# define TUNABLE_SET(__id, __type, __val) \ + TUNABLE_SET_FULL (TOP_NAMESPACE, TUNABLE_NAMESPACE, __id, __type, __val) +#else +# define TUNABLE_GET(__top, __ns, __id, __type, __cb) \ + TUNABLE_GET_FULL (__top, __ns, __id, __type, __cb) +# define TUNABLE_SET(__top, __ns, __id, __type, __val) \ + TUNABLE_SET_FULL (__top, __ns, __id, __type, __val) +#endif -/* Check if the tunable has been set to a non-default value and if it is, copy - it over into __VAL. */ -# define TUNABLE_SET_VAL(__id,__val) \ +/* Get and return a tunable value. If the tunable was set externally and __CB + is defined then call __CB before returning the value. */ +# define TUNABLE_GET_FULL(__top, __ns, __id, __type, __cb) \ ({ \ - __tunable_set_val \ - (TUNABLE_ENUM_NAME (TOP_NAMESPACE, TUNABLE_NAMESPACE, __id), (__val), \ - NULL); \ + tunable_id_t id = TUNABLE_ENUM_NAME (__top, __ns, __id); \ + __type ret; \ + __tunable_get_val (id, &ret, __cb); \ + ret; \ }) -/* Same as TUNABLE_SET_VAL, but also call the callback function __CB. */ -# define TUNABLE_SET_VAL_WITH_CALLBACK(__id,__val,__cb) \ +/* Set a tunable value. */ +# define TUNABLE_SET_FULL(__top, __ns, __id, __type, __val) \ ({ \ - __tunable_set_val \ - (TUNABLE_ENUM_NAME (TOP_NAMESPACE, TUNABLE_NAMESPACE, __id), (__val), \ - DL_TUNABLE_CALLBACK (__cb)); \ + __tunable_set_val (TUNABLE_ENUM_NAME (__top, __ns, __id), \ + & (__type) {__val}); \ }) /* Namespace sanity for callback functions. Use this macro to keep the namespace of the modules clean. */ -# define DL_TUNABLE_CALLBACK(__name) _dl_tunable_ ## __name +# define TUNABLE_CALLBACK(__name) _dl_tunable_ ## __name # define TUNABLES_FRONTEND_valstring 1 /* The default value for TUNABLES_FRONTEND. */ diff --git a/malloc/arena.c b/malloc/arena.c index d49e4a2..660d638 100644 --- a/malloc/arena.c +++ b/malloc/arena.c @@ -212,7 +212,7 @@ __malloc_fork_unlock_child (void) #if HAVE_TUNABLES static inline int do_set_mallopt_check (int32_t value); void -DL_TUNABLE_CALLBACK (set_mallopt_check) (tunable_val_t *valp) +TUNABLE_CALLBACK (set_mallopt_check) (tunable_val_t *valp) { int32_t value = (int32_t) valp->numval; do_set_mallopt_check (value); @@ -220,22 +220,22 @@ DL_TUNABLE_CALLBACK (set_mallopt_check) (tunable_val_t *valp) __malloc_check_init (); } -# define DL_TUNABLE_CALLBACK_FNDECL(__name, __type) \ +# define TUNABLE_CALLBACK_FNDECL(__name, __type) \ static inline int do_ ## __name (__type value); \ void \ -DL_TUNABLE_CALLBACK (__name) (tunable_val_t *valp) \ +TUNABLE_CALLBACK (__name) (tunable_val_t *valp) \ { \ __type value = (__type) (valp)->numval; \ do_ ## __name (value); \ } -DL_TUNABLE_CALLBACK_FNDECL (set_mmap_threshold, size_t) -DL_TUNABLE_CALLBACK_FNDECL (set_mmaps_max, int32_t) -DL_TUNABLE_CALLBACK_FNDECL (set_top_pad, size_t) -DL_TUNABLE_CALLBACK_FNDECL (set_perturb_byte, int32_t) -DL_TUNABLE_CALLBACK_FNDECL (set_trim_threshold, size_t) -DL_TUNABLE_CALLBACK_FNDECL (set_arena_max, size_t) -DL_TUNABLE_CALLBACK_FNDECL (set_arena_test, size_t) +TUNABLE_CALLBACK_FNDECL (set_mmap_threshold, size_t) +TUNABLE_CALLBACK_FNDECL (set_mmaps_max, int32_t) +TUNABLE_CALLBACK_FNDECL (set_top_pad, size_t) +TUNABLE_CALLBACK_FNDECL (set_perturb_byte, int32_t) +TUNABLE_CALLBACK_FNDECL (set_trim_threshold, size_t) +TUNABLE_CALLBACK_FNDECL (set_arena_max, size_t) +TUNABLE_CALLBACK_FNDECL (set_arena_test, size_t) #else /* Initialization routine. */ #include <string.h> @@ -314,14 +314,14 @@ ptmalloc_init (void) __libc_lock_lock (main_arena.mutex); malloc_consolidate (&main_arena); - TUNABLE_SET_VAL_WITH_CALLBACK (check, NULL, set_mallopt_check); - TUNABLE_SET_VAL_WITH_CALLBACK (top_pad, NULL, set_top_pad); - TUNABLE_SET_VAL_WITH_CALLBACK (perturb, NULL, set_perturb_byte); - TUNABLE_SET_VAL_WITH_CALLBACK (mmap_threshold, NULL, set_mmap_threshold); - TUNABLE_SET_VAL_WITH_CALLBACK (trim_threshold, NULL, set_trim_threshold); - TUNABLE_SET_VAL_WITH_CALLBACK (mmap_max, NULL, set_mmaps_max); - TUNABLE_SET_VAL_WITH_CALLBACK (arena_max, NULL, set_arena_max); - TUNABLE_SET_VAL_WITH_CALLBACK (arena_test, NULL, set_arena_test); + TUNABLE_GET (check, int32_t, TUNABLE_CALLBACK (set_mallopt_check)); + TUNABLE_GET (top_pad, size_t, TUNABLE_CALLBACK (set_top_pad)); + TUNABLE_GET (perturb, int32_t, TUNABLE_CALLBACK (set_perturb_byte)); + TUNABLE_GET (mmap_threshold, size_t, TUNABLE_CALLBACK (set_mmap_threshold)); + TUNABLE_GET (trim_threshold, size_t, TUNABLE_CALLBACK (set_trim_threshold)); + TUNABLE_GET (mmap_max, int32_t, TUNABLE_CALLBACK (set_mmaps_max)); + TUNABLE_GET (arena_max, size_t, TUNABLE_CALLBACK (set_arena_max)); + TUNABLE_GET (arena_test, size_t, TUNABLE_CALLBACK (set_arena_test)); __libc_lock_unlock (main_arena.mutex); #else const char *s = NULL; |