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(unknown [182.2.70.161]) by gnuweeb.org (Postfix) with ESMTPSA id 67C7A7E736; Tue, 29 Mar 2022 10:18:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=gnuweeb.org; s=default; t=1648549092; bh=4ayk0palimnVIsRYgwXKtHchFZ/kzcSyKrT7RjDdssQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=QYIJB9B6WLqpi0pvZ2g54PBXl0K8QYpmDfzFNOprQssxrGTfZXy7/ofwWo2qyJbbH /b9SNLnIihktUfxLCov2HfkRbjiqJziy+HYX2q+Wp4llDlRzbe04bSotQiSG88qF7G OaI0oyvw9+wylaa4XZVt0Qh6lB7IK1/IeK0qd/Gy/2Xl4LdqLUy3owjzc1iCIAEbd9 071ZYXdfTEDnSh5RY3j1aumnUVzFoy4oa1MaNaO8tAe/AsStAI/3HjBpmXGmlMdZb4 C4hKgYv9DQ5yv8RKvmdaP3e3PlhGE0zVE+OVqnABCZWn1G8J1FvDPzeTK+dSTiH25T W5dMYxhc9YwPg== From: Ammar Faizi To: Willy Tarreau Cc: Ammar Faizi , Alviro Iskandar Setiawan , Nugraha , "Paul E. McKenney" , Linux Kernel Mailing List , GNU/Weeb Mailing List , David Laight Subject: [PATCH v2 7/9] tools/nolibc/stdlib: Implement `malloc()`, `calloc()`, `realloc()` and `free()` Date: Tue, 29 Mar 2022 17:17:35 +0700 Message-Id: <20220329101737.58985-8-ammarfaizi2@gnuweeb.org> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20220329101737.58985-1-ammarfaizi2@gnuweeb.org> References: <20220329101737.58985-1-ammarfaizi2@gnuweeb.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit List-Id: Implement basic dynamic allocator functions. These functions are currently only available on architectures that have nolibc mmap() syscall implemented. These are not a super-fast memory allocator, but at least they can satisfy basic needs for having heap without libc. Cc: David Laight Signed-off-by: Ammar Faizi === @@ Changelog: Link v1: https://lore.gnuweeb.org/gwml/20220324073039.140946-10-ammarfaizi2@gnuweeb.org v1 -> v2: * No changes * Link v2: https://lore.kernel.org/lkml/20220322102115.186179-7-ammarfaizi2@gnuweeb.org RFC v2 -> v1: - Round up the malloc() allocation to 4096 (comment from David). - Don't realloc() if we still have enough memory to contain the requested new size (comment from David). - Fix conflict with getenv() fix (after rebase). Link v1: https://lore.kernel.org/lkml/20220320093750.159991-6-ammarfaizi2@gnuweeb.org RFC v1 -> RFC v2: - Move container_of() and offsetof() macro to types.h with a separate patch (comment from Willy). --- tools/include/nolibc/stdlib.h | 81 +++++++++++++++++++++++++++++++++++ 1 file changed, 81 insertions(+) diff --git a/tools/include/nolibc/stdlib.h b/tools/include/nolibc/stdlib.h index 8a07e263f0d0..8fd32eaf8037 100644 --- a/tools/include/nolibc/stdlib.h +++ b/tools/include/nolibc/stdlib.h @@ -11,7 +11,12 @@ #include "arch.h" #include "types.h" #include "sys.h" +#include "string.h" +struct nolibc_heap { + size_t len; + char user_p[] __attribute__((__aligned__)); +}; /* Buffer used to store int-to-ASCII conversions. Will only be implemented if * any of the related functions is implemented. The area is large enough to @@ -60,6 +65,18 @@ int atoi(const char *s) return atol(s); } +static __attribute__((unused)) +void free(void *ptr) +{ + struct nolibc_heap *heap; + + if (!ptr) + return; + + heap = container_of(ptr, struct nolibc_heap, user_p); + munmap(heap, heap->len); +} + /* getenv() tries to find the environment variable named in the * environment array pointed to by global variable "environ" which must be * declared as a char **, and must be terminated by a NULL (it is recommended @@ -91,6 +108,70 @@ char *getenv(const char *name) return _getenv(name, environ); } +static __attribute__((unused)) +void *malloc(size_t len) +{ + struct nolibc_heap *heap; + + /* Always allocate memory with size multiple of 4096. */ + len = sizeof(*heap) + len; + len = (len + 4095UL) & -4096UL; + heap = mmap(NULL, len, PROT_READ|PROT_WRITE, MAP_ANONYMOUS|MAP_PRIVATE, + -1, 0); + if (__builtin_expect(heap == MAP_FAILED, 0)) + return NULL; + + heap->len = len; + return heap->user_p; +} + +static __attribute__((unused)) +void *calloc(size_t size, size_t nmemb) +{ + void *orig; + size_t res = 0; + + if (__builtin_expect(__builtin_mul_overflow(nmemb, size, &res), 0)) { + SET_ERRNO(ENOMEM); + return NULL; + } + + /* + * No need to zero the heap, the MAP_ANONYMOUS in malloc() + * already does it. + */ + return malloc(res); +} + +static __attribute__((unused)) +void *realloc(void *old_ptr, size_t new_size) +{ + struct nolibc_heap *heap; + size_t user_p_len; + void *ret; + + if (!old_ptr) + return malloc(new_size); + + heap = container_of(old_ptr, struct nolibc_heap, user_p); + user_p_len = heap->len - sizeof(*heap); + /* + * Don't realloc() if @user_p_len >= @new_size, this block of + * memory is still enough to handle the @new_size. Just return + * the same pointer. + */ + if (user_p_len >= new_size) + return old_ptr; + + ret = malloc(new_size); + if (__builtin_expect(!ret, 0)) + return NULL; + + memcpy(ret, heap->user_p, heap->len); + munmap(heap, heap->len); + return ret; +} + /* Converts the unsigned long integer to its hex representation into * buffer , which must be long enough to store the number and the * trailing zero (17 bytes for "ffffffffffffffff" or 9 for "ffffffff"). The -- Ammar Faizi