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From: Siddhesh Poyarekar <siddhesh@sourceware.org> To: glibc-cvs@sourceware.org Subject: [glibc/siddhesh/malloc-hooks-new] Remove __morecore and __default_morecore Date: Mon, 5 Jul 2021 14:42:46 +0000 (GMT) [thread overview] Message-ID: <20210705144246.42A46385DC1C@sourceware.org> (raw) https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=3a7540810ddbd27f0aecd35c738cf0c44e331390 commit 3a7540810ddbd27f0aecd35c738cf0c44e331390 Author: Siddhesh Poyarekar <siddhesh@sourceware.org> Date: Thu Jun 24 23:12:59 2021 +0530 Remove __morecore and __default_morecore Make the __morecore and __default_morecore symbols compat-only and remove their declarations from the API. Diff: --- NEWS | 5 +++++ include/stdlib.h | 3 --- malloc/arena.c | 12 ++---------- malloc/hooks.c | 2 ++ malloc/malloc-internal.h | 5 +++++ malloc/malloc.c | 4 +--- malloc/malloc.h | 8 -------- malloc/morecore.c | 15 +++++++++++++-- 8 files changed, 28 insertions(+), 26 deletions(-) diff --git a/NEWS b/NEWS index 4fd4ff0e90..038420a621 100644 --- a/NEWS +++ b/NEWS @@ -113,6 +113,11 @@ Deprecated and removed features, and other changes affecting compatibility: future release of the GNU C Library. Users may port away from these hooks by writing and preloading their own malloc interposition library. +* The __morecore and __after_morecore_hook malloc hooks and the default + implementation __default_morecore have been removed from the API. Existing + applications will continue to link against these symbols but the interfaces + no longer have any effect on malloc. + Changes to build and runtime requirements: * On Linux, the shm_open, sem_open, and related functions now expect the diff --git a/include/stdlib.h b/include/stdlib.h index 1f6e1508e4..1c6f70b082 100644 --- a/include/stdlib.h +++ b/include/stdlib.h @@ -306,9 +306,6 @@ libc_hidden_proto (__qfcvt_r) # define MB_CUR_MAX (_NL_CURRENT_WORD (LC_CTYPE, _NL_CTYPE_MB_CUR_MAX)) # endif -extern void *__default_morecore (ptrdiff_t) __THROW; -libc_hidden_proto (__default_morecore) - struct abort_msg_s { unsigned int size; diff --git a/malloc/arena.c b/malloc/arena.c index 1ae57f43d5..0650b05c79 100644 --- a/malloc/arena.c +++ b/malloc/arena.c @@ -266,14 +266,6 @@ next_env_entry (char ***position) #endif -#if defined(SHARED) || defined(USE_MTAG) -static void * -__failing_morecore (ptrdiff_t d) -{ - return (void *) MORECORE_FAILURE; -} -#endif - #ifdef SHARED extern struct dl_open_hook *_dl_open_hook; libc_hidden_proto (_dl_open_hook); @@ -294,7 +286,7 @@ ptmalloc_init (void) and that morecore does not support tagged regions, then disable it. */ if (__MTAG_SBRK_UNTAGGED) - __morecore = __failing_morecore; + __always_fail_morecore = true; mtag_enabled = true; mtag_mmap_flags = __MTAG_MMAP_FLAGS; @@ -307,7 +299,7 @@ ptmalloc_init (void) generic sbrk implementation also enforces this, but it is not used on Hurd. */ if (!__libc_initial) - __morecore = __failing_morecore; + __always_fail_morecore = true; #endif thread_arena = &main_arena; diff --git a/malloc/hooks.c b/malloc/hooks.c index 50ea03b562..360e4920d1 100644 --- a/malloc/hooks.c +++ b/malloc/hooks.c @@ -46,6 +46,8 @@ compat_symbol (libc, __memalign_hook, __memalign_hook, GLIBC_2_0); void weak_variable (*__after_morecore_hook) (void) = NULL; compat_symbol (libc, __after_morecore_hook, __after_morecore_hook, GLIBC_2_0); +void *(*__morecore)(ptrdiff_t); +compat_symbol (libc, __morecore, __morecore, GLIBC_2_0); /* This is interposed by libc_malloc_debug.so to match with a compatible libc. We don't use dlsym or equivalent because the dlsym symbol version got bumped diff --git a/malloc/malloc-internal.h b/malloc/malloc-internal.h index 258f29584e..611aa97762 100644 --- a/malloc/malloc-internal.h +++ b/malloc/malloc-internal.h @@ -21,6 +21,7 @@ #include <malloc-machine.h> #include <malloc-sysdep.h> +#include <stdbool.h> /* INTERNAL_SIZE_T is the word-size used for internal bookkeeping of chunk sizes. @@ -62,6 +63,8 @@ #define MALLOC_ALIGN_MASK (MALLOC_ALIGNMENT - 1) +extern bool __always_fail_morecore attribute_hidden; + /* Called in the parent process before a fork. */ void __malloc_fork_lock_parent (void) attribute_hidden; @@ -77,4 +80,6 @@ void __malloc_arena_thread_freeres (void) attribute_hidden; /* Activate a standard set of debugging hooks. */ void __malloc_check_init (void) attribute_hidden; +extern void *__glibc_morecore (ptrdiff_t) attribute_hidden; + #endif /* _MALLOC_INTERNAL_H */ diff --git a/malloc/malloc.c b/malloc/malloc.c index 00fcc676a0..0b8c6d9086 100644 --- a/malloc/malloc.c +++ b/malloc/malloc.c @@ -382,10 +382,8 @@ __malloc_assert (const char *assertion, const char *file, unsigned int line, /* Definition for getting more memory from the OS. */ -#define MORECORE (*__morecore) +#define MORECORE (*__glibc_morecore) #define MORECORE_FAILURE 0 -void * __default_morecore (ptrdiff_t); -void *(*__morecore)(ptrdiff_t) = __default_morecore; /* Memory tagging. */ diff --git a/malloc/malloc.h b/malloc/malloc.h index d066a05d82..2df0b38050 100644 --- a/malloc/malloc.h +++ b/malloc/malloc.h @@ -76,14 +76,6 @@ extern void *valloc (size_t __size) __THROW __attribute_malloc__ extern void *pvalloc (size_t __size) __THROW __attribute_malloc__ __wur __attr_dealloc_free; -/* Underlying allocation function; successive calls should return - contiguous pieces of memory. */ -extern void *(*__morecore) (ptrdiff_t __size) __MALLOC_DEPRECATED; - -/* Default value of `__morecore'. */ -extern void *__default_morecore (ptrdiff_t __size) -__THROW __attribute_malloc__ __MALLOC_DEPRECATED; - /* SVID2/XPG mallinfo structure */ struct mallinfo diff --git a/malloc/morecore.c b/malloc/morecore.c index 047228779b..c85a85c0eb 100644 --- a/malloc/morecore.c +++ b/malloc/morecore.c @@ -38,16 +38,27 @@ libc_hidden_proto (__sbrk) # define NULL 0 #endif +#if defined(SHARED) || defined(USE_MTAG) +bool __always_fail_morecore = false; +#endif + /* Allocate INCREMENT more bytes of data space, and return the start of data space, or NULL on errors. If INCREMENT is negative, shrink data space. */ void * -__default_morecore (ptrdiff_t increment) +__glibc_morecore (ptrdiff_t increment) { +#if defined(SHARED) || defined(USE_MTAG) + if (__always_fail_morecore) + return NULL; +#endif + void *result = (void *) __sbrk (increment); if (result == (void *) -1) return NULL; return result; } -libc_hidden_def (__default_morecore) +#if SHLIB_COMPAT (libc, GLIBC_2_0, GLIBC_2_34) +compat_symbol (libc, __glibc_morecore, __default_morecore, GLIBC_2_0); +#endif
next reply other threads:[~2021-07-05 14:42 UTC|newest] Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-07-05 14:42 Siddhesh Poyarekar [this message] 2021-07-07 2:07 Siddhesh Poyarekar
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