Create `src/no_libc.c` to substitute libc functions like `memset()`, `malloc()` and `free()`. Only build this file when we build liburing without libc. Wrap libc functions with `static inline` functions, defined in `src/lib.h`, currently we have: 1) `get_page_size` 2) `uring_memset` 3) `uring_malloc` 4) `uring_free` Extra notes for tests: 1) Functions in `src/syscall.c` require libc to work. 2) Tests require functions in `src/syscall.c`. So we build `src/syscall.c` manually from test's Makefile. The Makefile in `src/` dir still builds `src/syscall.c` when we compile liburing with libc. Cc: Bedirhan KURT <windowz414@xxxxxxxxxxx> Cc: Louvian Lyndal <louvianlyndal@xxxxxxxxx> Link: https://github.com/axboe/liburing/issues/443 Signed-off-by: Ammar Faizi <ammar.faizi@xxxxxxxxxxxxxxxxxxxxx> --- src/Makefile | 13 +++++++++- src/lib.h | 69 ++++++++++++++++++++++++++++++++++++++++++++++++++ src/no_libc.c | 48 +++++++++++++++++++++++++++++++++++ src/queue.c | 1 + src/register.c | 1 + src/setup.c | 16 +++++------- src/syscall.c | 11 +++++++- test/Makefile | 23 ++++++++++++++--- 8 files changed, 167 insertions(+), 15 deletions(-) create mode 100644 src/lib.h create mode 100644 src/no_libc.c diff --git a/src/Makefile b/src/Makefile index 5e46a9d..3ca2ac7 100644 --- a/src/Makefile +++ b/src/Makefile @@ -32,11 +32,22 @@ endif all: $(all_targets) -liburing_srcs := setup.c queue.c syscall.c register.c +liburing_srcs := setup.c queue.c register.c + +ifeq ($(LIBURING_NOLIBC),y) + liburing_srcs += no_libc.c + override CFLAGS += -nostdlib -nolibc -nodefaultlibs -ffreestanding -fno-stack-protector -fpic + override CPPFLAGS += -nostdlib -nolibc -nodefaultlibs -ffreestanding -fno-stack-protector -fpic + override LINK_FLAGS += -nostdlib -nolibc -nodefaultlibs -fpic +else + liburing_srcs += syscall.c +endif liburing_objs := $(patsubst %.c,%.ol,$(liburing_srcs)) liburing_sobjs := $(patsubst %.c,%.os,$(liburing_srcs)) +$(liburing_srcs): syscall.h lib.h + $(liburing_objs) $(liburing_sobjs): include/liburing/io_uring.h %.os: %.c diff --git a/src/lib.h b/src/lib.h new file mode 100644 index 0000000..171eee7 --- /dev/null +++ b/src/lib.h @@ -0,0 +1,69 @@ +/* SPDX-License-Identifier: MIT */ +#ifndef LIBURING_LIB_H +#define LIBURING_LIB_H + +#include <stdlib.h> +#include <string.h> +#include <unistd.h> + +#ifndef offsetof +# define offsetof(TYPE, FIELD) ((size_t) &((TYPE *)0)->FIELD) +#endif + +#ifndef container_of +# define container_of(PTR, TYPE, FIELD) ({ \ + __typeof__(((TYPE *)0)->FIELD) *__FIELD_PTR = (PTR); \ + (TYPE *)((char *) __FIELD_PTR - offsetof(TYPE, FIELD)); \ +}) +#endif + + +static inline long get_page_size(void) +{ +#ifdef LIBURING_NOLIBC + return __arch_impl_get_page_size(); +#else + long page_size; + + page_size = sysconf(_SC_PAGESIZE); + if (page_size < 0) + page_size = 4096; + + return page_size; +#endif +} + +void *__uring_memset(void *s, int c, size_t n); + +static inline void *uring_memset(void *s, int c, size_t n) +{ +#ifdef LIBURING_NOLIBC + return __uring_memset(s, c, n); +#else + return memset(s, c, n); +#endif +} + +void *__uring_malloc(size_t len); + +static inline void *uring_malloc(size_t len) +{ +#ifdef LIBURING_NOLIBC + return __uring_malloc(len); +#else + return malloc(len); +#endif +} + +void __uring_free(void *p); + +static inline void uring_free(void *p) +{ +#ifdef LIBURING_NOLIBC + __uring_free(p); +#else + free(p); +#endif +} + +#endif /* #ifndef LIBURING_LIB_H */ diff --git a/src/no_libc.c b/src/no_libc.c new file mode 100644 index 0000000..149426c --- /dev/null +++ b/src/no_libc.c @@ -0,0 +1,48 @@ +/* SPDX-License-Identifier: MIT */ + +#ifndef LIBURING_NOLIBC +# error "This file should only be compiled for no libc build" +#endif + +#include "lib.h" +#include "syscall.h" + +void *__uring_memset(void *s, int c, size_t n) +{ + size_t i; + unsigned char *p = s; + + for (i = 0; i < n; i++) + p[i] = (unsigned char) c; + + return s; +} + +struct uring_heap { + size_t len; + char user_p[]; +}; + +void *__uring_malloc(size_t len) +{ + struct uring_heap *heap; + + heap = uring_mmap(NULL, sizeof(*heap) + len, PROT_READ | PROT_WRITE, + MAP_ANONYMOUS | MAP_PRIVATE, -1, 0); + if (IS_ERR(heap)) + return NULL; + + heap->len = sizeof(*heap) + len; + return heap->user_p; +} + +void __uring_free(void *p) +{ + struct uring_heap *heap; + + if (uring_unlikely(!p)) + return; + + heap = container_of(p, struct uring_heap, user_p); + uring_munmap(heap, heap->len); +} diff --git a/src/queue.c b/src/queue.c index 9af29d5..cd76048 100644 --- a/src/queue.c +++ b/src/queue.c @@ -13,6 +13,7 @@ #include "liburing.h" #include "liburing/barrier.h" +#include "lib.h" #include "syscall.h" /* diff --git a/src/register.c b/src/register.c index 074223f..f8e88cf 100644 --- a/src/register.c +++ b/src/register.c @@ -12,6 +12,7 @@ #include "liburing/io_uring.h" #include "liburing.h" +#include "lib.h" #include "syscall.h" int io_uring_register_buffers_update_tag(struct io_uring *ring, unsigned off, diff --git a/src/setup.c b/src/setup.c index 4f006de..0f64a35 100644 --- a/src/setup.c +++ b/src/setup.c @@ -12,6 +12,7 @@ #include "liburing/io_uring.h" #include "liburing.h" +#include "lib.h" #include "syscall.h" static void io_uring_unmap_rings(struct io_uring_sq *sq, struct io_uring_cq *cq) @@ -161,7 +162,7 @@ int io_uring_queue_init(unsigned entries, struct io_uring *ring, unsigned flags) { struct io_uring_params p; - memset(&p, 0, sizeof(p)); + uring_memset(&p, 0, sizeof(p)); p.flags = flags; return io_uring_queue_init_params(entries, ring, &p); @@ -184,16 +185,16 @@ struct io_uring_probe *io_uring_get_probe_ring(struct io_uring *ring) int r; len = sizeof(*probe) + 256 * sizeof(struct io_uring_probe_op); - probe = malloc(len); + probe = uring_malloc(len); if (!probe) return NULL; - memset(probe, 0, len); + uring_memset(probe, 0, len); r = io_uring_register_probe(ring, probe, 256); if (r >= 0) return probe; - free(probe); + uring_free(probe); return NULL; } @@ -214,7 +215,7 @@ struct io_uring_probe *io_uring_get_probe(void) void io_uring_free_probe(struct io_uring_probe *probe) { - free(probe); + uring_free(probe); } static int __fls(int x) @@ -336,10 +337,7 @@ ssize_t io_uring_mlock_size_params(unsigned entries, struct io_uring_params *p) cq_entries = 2 * entries; } - page_size = sysconf(_SC_PAGESIZE); - if (page_size < 0) - page_size = 4096; - + page_size = get_page_size(); return rings_size(entries, cq_entries, page_size); } diff --git a/src/syscall.c b/src/syscall.c index 5923fbb..cfb3ee2 100644 --- a/src/syscall.c +++ b/src/syscall.c @@ -1,6 +1,16 @@ /* SPDX-License-Identifier: MIT */ #define _DEFAULT_SOURCE +/* + * Functions in this file require libc, only build them when we use libc. + * + * Note: + * liburing's tests still need these functions. + */ +#if defined(LIBURING_NOLIBC) && !defined(LIBURING_BUILD_TEST) +# error "This file should only be compiled for libc build" +#endif + /* * Will go away once libc support is there */ @@ -11,7 +21,6 @@ #include "liburing/io_uring.h" #include "syscall.h" - int __sys_io_uring_register(int fd, unsigned opcode, const void *arg, unsigned nr_args) { diff --git a/test/Makefile b/test/Makefile index 2936469..ddb589b 100644 --- a/test/Makefile +++ b/test/Makefile @@ -21,8 +21,8 @@ ifdef CONFIG_HAVE_ARRAY_BOUNDS endif CXXFLAGS ?= $(CFLAGS) -override CFLAGS += $(XCFLAGS) -override CXXFLAGS += $(XCFLAGS) -std=c++11 +override CFLAGS += $(XCFLAGS) -DLIBURING_BUILD_TEST +override CXXFLAGS += $(XCFLAGS) -std=c++11 -DLIBURING_BUILD_TEST LDFLAGS ?= override LDFLAGS += -L../src/ -luring @@ -153,11 +153,26 @@ test_targets += sq-full-cpp endif all_targets += sq-full-cpp -helpers = helpers.o +# +# Note: +# +# Build ../src/syscall.c manually from test's Makefile to support +# build liburing without libc. +# +# Functions in ../src/syscall.c require libc to work with, if we +# build liburing.so without libc, we don't have those functions +# in liburing.so. +# +# This makes the tests can run for liburing.so without libc. +# +helpers = helpers.o ../src/syscall.o all: ${helpers} $(test_targets) -helpers.o: helpers.c helpers.c +../src/syscall.o: ../src/syscall.c + $(QUIET_CC)$(CC) $(CPPFLAGS) $(CFLAGS) -o $@ -c $< + +helpers.o: helpers.c $(QUIET_CC)$(CC) $(CPPFLAGS) $(CFLAGS) -o $@ -c $< %: %.c ${helpers} helpers.h -- 2.30.2
