libc-hooks.c

/*
 * Copyright (c) 2015, Intel Corporation.
 *
 * SPDX-License-Identifier: Apache-2.0
 */

#include <zephyr/arch/cpu.h>
#include <errno.h>
#include <stdio.h>
#include <malloc.h>
#include <zephyr/sys/__assert.h>
#include <zephyr/posix/sys/stat.h>
#include <zephyr/linker/linker-defs.h>
#include <zephyr/sys/util.h>
#include <zephyr/sys/errno_private.h>
#include <zephyr/sys/heap_listener.h>
#include <zephyr/sys/libc-hooks.h>
#include <zephyr/internal/syscall_handler.h>
#include <zephyr/app_memory/app_memdomain.h>
#include <zephyr/init.h>
#include <zephyr/sys/sem.h>
#include <zephyr/sys/mutex.h>
#include <zephyr/kernel/mm.h>
#include <sys/time.h>

int _fstat(int fd, struct stat *st);
int _read(int fd, void *buf, int nbytes);
int _write(int fd, const void *buf, int nbytes);
int _open(const char *name, int mode);
int _close(int file);
int _lseek(int file, int ptr, int dir);
int _kill(int pid, int sig);
int _getpid(void);

#ifndef CONFIG_NEWLIB_LIBC_CUSTOM_SBRK

#define LIBC_BSS	K_APP_BMEM(z_libc_partition)
#define LIBC_DATA	K_APP_DMEM(z_libc_partition)

/*
 * End result of this thorny set of ifdefs is to define:
 *
 * - HEAP_BASE base address of the heap arena
 * - MAX_HEAP_SIZE size of the heap arena
 */

#ifdef CONFIG_MMU
	#ifdef CONFIG_USERSPACE
		struct k_mem_partition z_malloc_partition;
	#endif

	LIBC_BSS static unsigned char *heap_base;
	LIBC_BSS static size_t max_heap_size;

	#define HEAP_BASE		heap_base
	#define MAX_HEAP_SIZE		max_heap_size
	#define USE_MALLOC_PREPARE	1
#elif CONFIG_NEWLIB_LIBC_ALIGNED_HEAP_SIZE
	/* Arena size expressed in Kconfig, due to power-of-two size/align
	 * requirements of certain MPUs.
	 *
	 * We use an automatic memory partition instead of setting this up
	 * in malloc_prepare().
	 */
	K_APPMEM_PARTITION_DEFINE(z_malloc_partition);
	#define MALLOC_BSS	K_APP_BMEM(z_malloc_partition)

	/* Compiler will throw an error if the provided value isn't a
	 * power of two
	 */
	MALLOC_BSS static unsigned char
		__aligned(CONFIG_NEWLIB_LIBC_ALIGNED_HEAP_SIZE)
		heap_base[CONFIG_NEWLIB_LIBC_ALIGNED_HEAP_SIZE];
	#define MAX_HEAP_SIZE CONFIG_NEWLIB_LIBC_ALIGNED_HEAP_SIZE
	#define HEAP_BASE heap_base
#else /* Not MMU or CONFIG_NEWLIB_LIBC_ALIGNED_HEAP_SIZE */
	#define USED_RAM_END_ADDR   POINTER_TO_UINT(&_end)

	#ifdef Z_MALLOC_PARTITION_EXISTS
		/* Start of malloc arena needs to be aligned per MPU
		 * requirements
		 */
		struct k_mem_partition z_malloc_partition;

		#if defined(CONFIG_ARM) || defined(CONFIG_ARM64)
			#define HEAP_BASE	ROUND_UP(USED_RAM_END_ADDR, \
				 CONFIG_ARM_MPU_REGION_MIN_ALIGN_AND_SIZE)
		#elif defined(CONFIG_ARC)
			#define HEAP_BASE	ROUND_UP(USED_RAM_END_ADDR, \
							  Z_ARC_MPU_ALIGN)
		#else
			#error "Unsupported platform"
		#endif /* CONFIG_<arch> */
		#define USE_MALLOC_PREPARE	1
	#else
		/* End of kernel image */
		#define HEAP_BASE		USED_RAM_END_ADDR
	#endif

	/* End of the malloc arena is the end of physical memory */
	#if defined(CONFIG_XTENSA)
		/* TODO: Why is xtensa a special case? */
		extern char _heap_sentry[];
		#define MAX_HEAP_SIZE	(POINTER_TO_UINT(&_heap_sentry) - \
					 HEAP_BASE)
	#else
		#define MAX_HEAP_SIZE	(KB(CONFIG_SRAM_SIZE) - (HEAP_BASE - \
					 CONFIG_SRAM_BASE_ADDRESS))
	#endif /* CONFIG_XTENSA */
#endif

static int malloc_prepare(void)
{

#ifdef USE_MALLOC_PREPARE
#ifdef CONFIG_MMU
	max_heap_size = MIN(CONFIG_NEWLIB_LIBC_MAX_MAPPED_REGION_SIZE,
			    k_mem_free_get());

	if (max_heap_size != 0) {
		heap_base = k_mem_map(max_heap_size, K_MEM_PERM_RW);
		__ASSERT(heap_base != NULL,
			 "failed to allocate heap of size %zu", max_heap_size);

	}
#endif /* CONFIG_MMU */

#ifdef Z_MALLOC_PARTITION_EXISTS
	z_malloc_partition.start = (uintptr_t)HEAP_BASE;
	z_malloc_partition.size = (size_t)MAX_HEAP_SIZE;
	z_malloc_partition.attr = K_MEM_PARTITION_P_RW_U_RW;
#endif /* Z_MALLOC_PARTITION_EXISTS */
#endif /* USE_MALLOC_PREPARE */

	/*
	 * Validate that the memory space available for the newlib heap is
	 * greater than the minimum required size.
	 */
	__ASSERT(MAX_HEAP_SIZE >= CONFIG_NEWLIB_LIBC_MIN_REQUIRED_HEAP_SIZE,
		 "memory space available for newlib heap is less than the "
		 "minimum required size specified by "
		 "CONFIG_NEWLIB_LIBC_MIN_REQUIRED_HEAP_SIZE");

	return 0;
}

SYS_INIT(malloc_prepare, POST_KERNEL, CONFIG_KERNEL_INIT_PRIORITY_LIBC);

/* Current offset from HEAP_BASE of unused memory */
LIBC_BSS static size_t heap_sz;
#endif /* CONFIG_NEWLIB_LIBC_CUSTOM_SBRK */

static int _stdout_hook_default(int c)
{
	(void)(c);  /* Prevent warning about unused argument */

	return EOF;
}

static int (*_stdout_hook)(int) = _stdout_hook_default;

void __stdout_hook_install(int (*hook)(int))
{
	_stdout_hook = hook;
}

static unsigned char _stdin_hook_default(void)
{
	return 0;
}

static unsigned char (*_stdin_hook)(void) = _stdin_hook_default;

void __stdin_hook_install(unsigned char (*hook)(void))
{
	_stdin_hook = hook;
}

int z_impl_zephyr_read_stdin(char *buf, int nbytes)
{
	int i = 0;

	for (i = 0; i < nbytes; i++) {
		*(buf + i) = _stdin_hook();
		if ((*(buf + i) == '\n') || (*(buf + i) == '\r')) {
			i++;
			break;
		}
	}
	return i;
}

#ifdef CONFIG_USERSPACE
static inline int z_vrfy_zephyr_read_stdin(char *buf, int nbytes)
{
	K_OOPS(K_SYSCALL_MEMORY_WRITE(buf, nbytes));
	return z_impl_zephyr_read_stdin((char *)buf, nbytes);
}
#include <zephyr/syscalls/zephyr_read_stdin_mrsh.c>
#endif

int z_impl_zephyr_write_stdout(const void *buffer, int nbytes)
{
	const char *buf = buffer;
	int i;

	for (i = 0; i < nbytes; i++) {
		if (*(buf + i) == '\n') {
			_stdout_hook('\r');
		}
		_stdout_hook(*(buf + i));
	}
	return nbytes;
}

#ifdef CONFIG_USERSPACE
static inline int z_vrfy_zephyr_write_stdout(const void *buf, int nbytes)
{
	K_OOPS(K_SYSCALL_MEMORY_READ(buf, nbytes));
	return z_impl_zephyr_write_stdout((const void *)buf, nbytes);
}
#include <zephyr/syscalls/zephyr_write_stdout_mrsh.c>
#endif

#ifndef CONFIG_POSIX_DEVICE_IO
int _read(int fd, void *buf, int nbytes)
{
	ARG_UNUSED(fd);

	return zephyr_read_stdin(buf, nbytes);
}
__weak FUNC_ALIAS(_read, read, int);

int _write(int fd, const void *buf, int nbytes)
{
	ARG_UNUSED(fd);

	return zephyr_write_stdout(buf, nbytes);
}
__weak FUNC_ALIAS(_write, write, int);

int _open(const char *name, int mode)
{
	return -1;
}
__weak FUNC_ALIAS(_open, open, int);

int _close(int file)
{
	return -1;
}
__weak FUNC_ALIAS(_close, close, int);
#endif /* CONFIG_POSIX_DEVICE_IO */

#ifndef CONFIG_POSIX_FD_MGMT
int _lseek(int file, int ptr, int dir)
{
	return 0;
}
__weak FUNC_ALIAS(_lseek, lseek, int);
#endif /* CONFIG_POSIX_FD_MGMT */

int _isatty(int file)
{
	return file <= 2;
}
__weak FUNC_ALIAS(_isatty, isatty, int);

#ifndef CONFIG_POSIX_SIGNALS
int _kill(int i, int j)
{
	return 0;
}
__weak FUNC_ALIAS(_kill, kill, int);
#endif /* CONFIG_POSIX_SIGNALS */

#ifndef CONFIG_POSIX_FILE_SYSTEM
int _fstat(int file, struct stat *st)
{
	st->st_mode = S_IFCHR;
	return 0;
}
__weak FUNC_ALIAS(_fstat, fstat, int);
#endif /* CONFIG_POSIX_FILE_SYSTEM */

#ifndef CONFIG_POSIX_MULTI_PROCESS
int _getpid(void)
{
	return 0;
}
__weak FUNC_ALIAS(_getpid, getpid, int);

#endif /* CONFIG_POSIX_MULTI_PROCESS */

__weak void _exit(int status)
{
	_write(1, "exit\n", 5);
	while (1) {
		;
	}
}

#ifndef CONFIG_NEWLIB_LIBC_CUSTOM_SBRK
void *_sbrk(intptr_t count)
{
	void *ret, *ptr;

	ptr = ((char *)HEAP_BASE) + heap_sz;

	if ((heap_sz + count) < MAX_HEAP_SIZE) {
		heap_sz += count;
		ret = ptr;

#ifdef CONFIG_NEWLIB_LIBC_HEAP_LISTENER
		heap_listener_notify_resize(HEAP_ID_LIBC, ptr, (char *)ptr + count);
#endif
	} else {
		ret = (void *)-1;
	}

	return ret;
}
__weak FUNC_ALIAS(_sbrk, sbrk, void *);
#endif /* CONFIG_NEWLIB_LIBC_CUSTOM_SBRK */

#ifdef CONFIG_MULTITHREADING

/* Make sure _RETARGETABLE_LOCKING is enabled in toolchain */
BUILD_ASSERT(IS_ENABLED(_RETARGETABLE_LOCKING), "Retargetable locking must be enabled");

/*
 * Newlib Retargetable Locking Interface Implementation
 *
 * When multithreading is enabled, the newlib retargetable locking interface is
 * defined below to override the default void implementation and provide the
 * Zephyr-side locks.
 *
 * NOTE: `k_mutex` and `k_sem` are used instead of `sys_mutex` and `sys_sem`
 *	 because the latter do not support dynamic allocation for now.
 */

/* Static locks */
K_MUTEX_DEFINE(__lock___sinit_recursive_mutex);
K_MUTEX_DEFINE(__lock___sfp_recursive_mutex);
K_MUTEX_DEFINE(__lock___atexit_recursive_mutex);
K_MUTEX_DEFINE(__lock___malloc_recursive_mutex);
K_MUTEX_DEFINE(__lock___env_recursive_mutex);
K_SEM_DEFINE(__lock___at_quick_exit_mutex, 1, 1);
K_SEM_DEFINE(__lock___tz_mutex, 1, 1);
K_SEM_DEFINE(__lock___dd_hash_mutex, 1, 1);
K_SEM_DEFINE(__lock___arc4random_mutex, 1, 1);

#ifdef CONFIG_USERSPACE
/* Grant public access to all static locks after boot */
static int newlib_locks_prepare(void)
{

	/* Initialise recursive locks */
	k_object_access_all_grant(&__lock___sinit_recursive_mutex);
	k_object_access_all_grant(&__lock___sfp_recursive_mutex);
	k_object_access_all_grant(&__lock___atexit_recursive_mutex);
	k_object_access_all_grant(&__lock___malloc_recursive_mutex);
	k_object_access_all_grant(&__lock___env_recursive_mutex);

	/* Initialise non-recursive locks */
	k_object_access_all_grant(&__lock___at_quick_exit_mutex);
	k_object_access_all_grant(&__lock___tz_mutex);
	k_object_access_all_grant(&__lock___dd_hash_mutex);
	k_object_access_all_grant(&__lock___arc4random_mutex);

	return 0;
}

SYS_INIT(newlib_locks_prepare, POST_KERNEL,
	 CONFIG_KERNEL_INIT_PRIORITY_DEFAULT);
#endif /* CONFIG_USERSPACE */

/* Create a new dynamic non-recursive lock */
void __retarget_lock_init(_LOCK_T *lock)
{
	__ASSERT_NO_MSG(lock != NULL);

	/* Allocate semaphore object */
#ifndef CONFIG_USERSPACE
	*lock = malloc(sizeof(struct k_sem));
#else
	*lock = k_object_alloc(K_OBJ_SEM);
#endif /* !CONFIG_USERSPACE */
	__ASSERT(*lock != NULL, "non-recursive lock allocation failed");

	k_sem_init((struct k_sem *)*lock, 1, 1);
#ifdef CONFIG_USERSPACE
	k_object_access_all_grant(*lock);
#endif /* CONFIG_USERSPACE */
}

/* Create a new dynamic recursive lock */
void __retarget_lock_init_recursive(_LOCK_T *lock)
{
	__ASSERT_NO_MSG(lock != NULL);

	/* Allocate mutex object */
#ifndef CONFIG_USERSPACE
	*lock = malloc(sizeof(struct k_mutex));
#else
	*lock = k_object_alloc(K_OBJ_MUTEX);
#endif /* !CONFIG_USERSPACE */
	__ASSERT(*lock != NULL, "recursive lock allocation failed");

	k_mutex_init((struct k_mutex *)*lock);
#ifdef CONFIG_USERSPACE
	k_object_access_all_grant(*lock);
#endif /* CONFIG_USERSPACE */
}

/* Close dynamic non-recursive lock */
void __retarget_lock_close(_LOCK_T lock)
{
	__ASSERT_NO_MSG(lock != NULL);
#ifndef CONFIG_USERSPACE
	free(lock);
#else
	k_object_release(lock);
#endif /* !CONFIG_USERSPACE */
}

/* Close dynamic recursive lock */
void __retarget_lock_close_recursive(_LOCK_T lock)
{
	__ASSERT_NO_MSG(lock != NULL);
#ifndef CONFIG_USERSPACE
	free(lock);
#else
	k_object_release(lock);
#endif /* !CONFIG_USERSPACE */
}

/* Acquiure non-recursive lock */
void __retarget_lock_acquire(_LOCK_T lock)
{
	__ASSERT_NO_MSG(lock != NULL);
	k_sem_take((struct k_sem *)lock, K_FOREVER);
}

/* Acquiure recursive lock */
void __retarget_lock_acquire_recursive(_LOCK_T lock)
{
	__ASSERT_NO_MSG(lock != NULL);
	k_mutex_lock((struct k_mutex *)lock, K_FOREVER);
}

/* Try acquiring non-recursive lock */
int __retarget_lock_try_acquire(_LOCK_T lock)
{
	__ASSERT_NO_MSG(lock != NULL);
	return !k_sem_take((struct k_sem *)lock, K_NO_WAIT);
}

/* Try acquiring recursive lock */
int __retarget_lock_try_acquire_recursive(_LOCK_T lock)
{
	__ASSERT_NO_MSG(lock != NULL);
	return !k_mutex_lock((struct k_mutex *)lock, K_NO_WAIT);
}

/* Release non-recursive lock */
void __retarget_lock_release(_LOCK_T lock)
{
	__ASSERT_NO_MSG(lock != NULL);
	k_sem_give((struct k_sem *)lock);
}

/* Release recursive lock */
void __retarget_lock_release_recursive(_LOCK_T lock)
{
	__ASSERT_NO_MSG(lock != NULL);
	k_mutex_unlock((struct k_mutex *)lock);
}
#endif /* CONFIG_MULTITHREADING */

__weak int *__errno(void)
{
	return z_errno();
}

/* This function gets called if static buffer overflow detection is enabled
 * on stdlib side (Newlib here), in case such an overflow is detected. Newlib
 * provides an implementation not suitable for us, so we override it here.
 */
__weak FUNC_NORETURN void __chk_fail(void)
{
	static const char chk_fail_msg[] = "* buffer overflow detected *\n";
	_write(2, chk_fail_msg, sizeof(chk_fail_msg) - 1);
	k_oops();
	CODE_UNREACHABLE;
}

#if CONFIG_XTENSA
/* The Newlib in xtensa toolchain has a few missing functions for the
 * reentrant versions of the syscalls.
 */
_ssize_t _read_r(struct _reent *r, int fd, void *buf, size_t nbytes)
{
	ARG_UNUSED(r);

	return _read(fd, (char *)buf, nbytes);
}

_ssize_t _write_r(struct _reent *r, int fd, const void *buf, size_t nbytes)
{
	ARG_UNUSED(r);

	return _write(fd, buf, nbytes);
}

int _open_r(struct _reent *r, const char *name, int flags, int mode)
{
	ARG_UNUSED(r);
	ARG_UNUSED(flags);

	return _open(name, mode);
}

int _close_r(struct _reent *r, int file)
{
	ARG_UNUSED(r);

	return _close(file);
}

_off_t _lseek_r(struct _reent *r, int file, _off_t ptr, int dir)
{
	ARG_UNUSED(r);

	return _lseek(file, ptr, dir);
}

int _isatty_r(struct _reent *r, int file)
{
	ARG_UNUSED(r);

	return _isatty(file);
}

int _kill_r(struct _reent *r, int i, int j)
{
	ARG_UNUSED(r);

	return _kill(i, j);
}

int _getpid_r(struct _reent *r)
{
	ARG_UNUSED(r);

	return _getpid();
}

int _fstat_r(struct _reent *r, int file, struct stat *st)
{
	ARG_UNUSED(r);

	return _fstat(file, st);
}

void _exit_r(struct _reent *r, int status)
{
	ARG_UNUSED(r);

	_exit(status);
}

void *_sbrk_r(struct _reent *r, int count)
{
	ARG_UNUSED(r);

	return _sbrk(count);
}
#endif /* CONFIG_XTENSA */

int _gettimeofday(struct timeval *__tp, void *__tzp)
{
#ifdef CONFIG_XSI_SINGLE_PROCESS
	return gettimeofday(__tp, __tzp);
#else
	/* Non-posix systems should not call gettimeofday() here as it will
	 * result in a recursive call loop and result in a stack overflow.
	 */
	return -1;
#endif
}