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/* SPDX-License-Identifier: LGPL-2.1 OR MIT */
/* nolibc.h
* Copyright (C) 2017-2018 Willy Tarreau <w@1wt.eu>
*/
/*
* This file is designed to be used as a libc alternative for minimal programs
* with very limited requirements. It consists of a small number of syscall and
* type definitions, and the minimal startup code needed to call main().
* All syscalls are declared as static functions so that they can be optimized
* away by the compiler when not used.
*
* Syscalls are split into 3 levels:
* - The lower level is the arch-specific syscall() definition, consisting in
* assembly code in compound expressions. These are called my_syscall0() to
* my_syscall6() depending on the number of arguments. The MIPS
* implementation is limited to 5 arguments. All input arguments are cast
* to a long stored in a register. These expressions always return the
* syscall's return value as a signed long value which is often either a
* pointer or the negated errno value.
*
* - The second level is mostly architecture-independent. It is made of
* static functions called sys_<name>() which rely on my_syscallN()
* depending on the syscall definition. These functions are responsible
* for exposing the appropriate types for the syscall arguments (int,
* pointers, etc) and for setting the appropriate return type (often int).
* A few of them are architecture-specific because the syscalls are not all
* mapped exactly the same among architectures. For example, some archs do
* not implement select() and need pselect6() instead, so the sys_select()
* function will have to abstract this.
*
* - The third level is the libc call definition. It exposes the lower raw
* sys_<name>() calls in a way that looks like what a libc usually does,
* takes care of specific input values, and of setting errno upon error.
* There can be minor variations compared to standard libc calls. For
* example the open() call always takes 3 args here.
*
* The errno variable is declared static and unused. This way it can be
* optimized away if not used. However this means that a program made of
* multiple C files may observe different errno values (one per C file). For
* the type of programs this project targets it usually is not a problem. The
* resulting program may even be reduced by defining the NOLIBC_IGNORE_ERRNO
* macro, in which case the errno value will never be assigned.
*
* Some stdint-like integer types are defined. These are valid on all currently
* supported architectures, because signs are enforced, ints are assumed to be
* 32 bits, longs the size of a pointer and long long 64 bits. If more
* architectures have to be supported, this may need to be adapted.
*
* Some macro definitions like the O_* values passed to open(), and some
* structures like the sys_stat struct depend on the architecture.
*
* The definitions start with the architecture-specific parts, which are picked
* based on what the compiler knows about the target architecture, and are
* completed with the generic code. Since it is the compiler which sets the
* target architecture, cross-compiling normally works out of the box without
* having to specify anything.
*
* Finally some very common libc-level functions are provided. It is the case
* for a few functions usually found in string.h, ctype.h, or stdlib.h. Nothing
* is currently provided regarding stdio emulation.
*
* The macro NOLIBC is always defined, so that it is possible for a program to
* check this macro to know if it is being built against and decide to disable
* some features or simply not to include some standard libc files.
*
* Ideally this file should be split in multiple files for easier long term
* maintenance, but provided as a single file as it is now, it's quite
* convenient to use. Maybe some variations involving a set of includes at the
* top could work.
*
* A simple static executable may be built this way :
* $ gcc -fno-asynchronous-unwind-tables -fno-ident -s -Os -nostdlib \
* -static -include nolibc.h -o hello hello.c -lgcc
*
* A very useful calling convention table may be found here :
* http://man7.org/linux/man-pages/man2/syscall.2.html
*
* This doc is quite convenient though not necessarily up to date :
* https://w3challs.com/syscalls/
*
*/
#include <asm/unistd.h>
#include <asm/ioctls.h>
#include <asm/errno.h>
#include <linux/fs.h>
#include <linux/loop.h>
#include <linux/time.h>
#define NOLIBC
/* this way it will be removed if unused */
static int errno;
#ifndef NOLIBC_IGNORE_ERRNO
#define SET_ERRNO(v) do { errno = (v); } while (0)
#else
#define SET_ERRNO(v) do { } while (0)
#endif
/* errno codes all ensure that they will not conflict with a valid pointer
* because they all correspond to the highest addressable memory page.
*/
#define MAX_ERRNO 4095
/* Declare a few quite common macros and types that usually are in stdlib.h,
* stdint.h, ctype.h, unistd.h and a few other common locations.
*/
#define NULL ((void *)0)
/* stdint types */
typedef unsigned char uint8_t;
typedef signed char int8_t;
typedef unsigned short uint16_t;
typedef signed short int16_t;
typedef unsigned int uint32_t;
typedef signed int int32_t;
typedef unsigned long long uint64_t;
typedef signed long long int64_t;
typedef unsigned long size_t;
typedef signed long ssize_t;
typedef unsigned long uintptr_t;
typedef signed long intptr_t;
typedef signed long ptrdiff_t;
/* for stat() */
typedef unsigned int dev_t;
typedef unsigned long ino_t;
typedef unsigned int mode_t;
typedef signed int pid_t;
typedef unsigned int uid_t;
typedef unsigned int gid_t;
typedef unsigned long nlink_t;
typedef signed long off_t;
typedef signed long blksize_t;
typedef signed long blkcnt_t;
typedef signed long time_t;
/* for poll() */
struct pollfd {
int fd;
short int events;
short int revents;
};
/* for getdents64() */
struct linux_dirent64 {
uint64_t d_ino;
int64_t d_off;
unsigned short d_reclen;
unsigned char d_type;
char d_name[];
};
/* commonly an fd_set represents 256 FDs */
#define FD_SETSIZE 256
typedef struct { uint32_t fd32[FD_SETSIZE/32]; } fd_set;
/* needed by wait4() */
struct rusage {
struct timeval ru_utime;
struct timeval ru_stime;
long ru_maxrss;
long ru_ixrss;
long ru_idrss;
long ru_isrss;
long ru_minflt;
long ru_majflt;
long ru_nswap;
long ru_inblock;
long ru_oublock;
long ru_msgsnd;
long ru_msgrcv;
long ru_nsignals;
long ru_nvcsw;
long ru_nivcsw;
};
/* stat flags (WARNING, octal here) */
#define S_IFDIR 0040000
#define S_IFCHR 0020000
#define S_IFBLK 0060000
#define S_IFREG 0100000
#define S_IFIFO 0010000
#define S_IFLNK 0120000
#define S_IFSOCK 0140000
#define S_IFMT 0170000
#define S_ISDIR(mode) (((mode) & S_IFDIR) == S_IFDIR)
#define S_ISCHR(mode) (((mode) & S_IFCHR) == S_IFCHR)
#define S_ISBLK(mode) (((mode) & S_IFBLK) == S_IFBLK)
#define S_ISREG(mode) (((mode) & S_IFREG) == S_IFREG)
#define S_ISFIFO(mode) (((mode) & S_IFIFO) == S_IFIFO)
#define S_ISLNK(mode) (((mode) & S_IFLNK) == S_IFLNK)
#define S_ISSOCK(mode) (((mode) & S_IFSOCK) == S_IFSOCK)
#define DT_UNKNOWN 0
#define DT_FIFO 1
#define DT_CHR 2
#define DT_DIR 4
#define DT_BLK 6
#define DT_REG 8
#define DT_LNK 10
#define DT_SOCK 12
/* all the *at functions */
#ifndef AT_FDCWD
#define AT_FDCWD -100
#endif
/* lseek */
#define SEEK_SET 0
#define SEEK_CUR 1
#define SEEK_END 2
/* reboot */
#define LINUX_REBOOT_MAGIC1 0xfee1dead
#define LINUX_REBOOT_MAGIC2 0x28121969
#define LINUX_REBOOT_CMD_HALT 0xcdef0123
#define LINUX_REBOOT_CMD_POWER_OFF 0x4321fedc
#define LINUX_REBOOT_CMD_RESTART 0x01234567
#define LINUX_REBOOT_CMD_SW_SUSPEND 0xd000fce2
/* The format of the struct as returned by the libc to the application, which
* significantly differs from the format returned by the stat() syscall flavours.
*/
struct stat {
dev_t st_dev; /* ID of device containing file */
ino_t st_ino; /* inode number */
mode_t st_mode; /* protection */
nlink_t st_nlink; /* number of hard links */
uid_t st_uid; /* user ID of owner */
gid_t st_gid; /* group ID of owner */
dev_t st_rdev; /* device ID (if special file) */
off_t st_size; /* total size, in bytes */
blksize_t st_blksize; /* blocksize for file system I/O */
blkcnt_t st_blocks; /* number of 512B blocks allocated */
time_t st_atime; /* time of last access */
time_t st_mtime; /* time of last modification */
time_t st_ctime; /* time of last status change */
};
#define WEXITSTATUS(status) (((status) & 0xff00) >> 8)
#define WIFEXITED(status) (((status) & 0x7f) == 0)
/* for SIGCHLD */
#include <asm/signal.h>
/* Below comes the architecture-specific code. For each architecture, we have
* the syscall declarations and the _start code definition. This is the only
* global part. On all architectures the kernel puts everything in the stack
* before jumping to _start just above us, without any return address (_start
* is not a function but an entry pint). So at the stack pointer we find argc.
* Then argv[] begins, and ends at the first NULL. Then we have envp which
* starts and ends with a NULL as well. So envp=argv+argc+1.
*/
#if defined(__x86_64__)
/* Syscalls for x86_64 :
* - registers are 64-bit
* - syscall number is passed in rax
* - arguments are in rdi, rsi, rdx, r10, r8, r9 respectively
* - the system call is performed by calling the syscall instruction
* - syscall return comes in rax
* - rcx and r11 are clobbered, others are preserved.
* - the arguments are cast to long and assigned into the target registers
* which are then simply passed as registers to the asm code, so that we
* don't have to experience issues with register constraints.
* - the syscall number is always specified last in order to allow to force
* some registers before (gcc refuses a %-register at the last position).
* - see also x86-64 ABI section A.2 AMD64 Linux Kernel Conventions, A.2.1
* Calling Conventions.
*
* Link x86-64 ABI: https://gitlab.com/x86-psABIs/x86-64-ABI/-/wikis/x86-64-psABI
*
*/
#define my_syscall0(num) \
({ \
long _ret; \
register long _num asm("rax") = (num); \
\
asm volatile ( \
"syscall\n" \
: "=a"(_ret) \
: "0"(_num) \
: "rcx", "r11", "memory", "cc" \
); \
_ret; \
})
#define my_syscall1(num, arg1) \
({ \
long _ret; \
register long _num asm("rax") = (num); \
register long _arg1 asm("rdi") = (long)(arg1); \
\
asm volatile ( \
"syscall\n" \
: "=a"(_ret) \
: "r"(_arg1), \
"0"(_num) \
: "rcx", "r11", "memory", "cc" \
); \
_ret; \
})
#define my_syscall2(num, arg1, arg2) \
({ \
long _ret; \
register long _num asm("rax") = (num); \
register long _arg1 asm("rdi") = (long)(arg1); \
register long _arg2 asm("rsi") = (long)(arg2); \
\
asm volatile ( \
"syscall\n" \
: "=a"(_ret) \
: "r"(_arg1), "r"(_arg2), \
"0"(_num) \
: "rcx", "r11", "memory", "cc" \
); \
_ret; \
})
#define my_syscall3(num, arg1, arg2, arg3) \
({ \
long _ret; \
register long _num asm("rax") = (num); \
register long _arg1 asm("rdi") = (long)(arg1); \
register long _arg2 asm("rsi") = (long)(arg2); \
register long _arg3 asm("rdx") = (long)(arg3); \
\
asm volatile ( \
"syscall\n" \
: "=a"(_ret) \
: "r"(_arg1), "r"(_arg2), "r"(_arg3), \
"0"(_num) \
: "rcx", "r11", "memory", "cc" \
); \
_ret; \
})
#define my_syscall4(num, arg1, arg2, arg3, arg4) \
({ \
long _ret; \
register long _num asm("rax") = (num); \
register long _arg1 asm("rdi") = (long)(arg1); \
register long _arg2 asm("rsi") = (long)(arg2); \
register long _arg3 asm("rdx") = (long)(arg3); \
register long _arg4 asm("r10") = (long)(arg4); \
\
asm volatile ( \
"syscall\n" \
: "=a"(_ret) \
: "r"(_arg1), "r"(_arg2), "r"(_arg3), "r"(_arg4), \
"0"(_num) \
: "rcx", "r11", "memory", "cc" \
); \
_ret; \
})
#define my_syscall5(num, arg1, arg2, arg3, arg4, arg5) \
({ \
long _ret; \
register long _num asm("rax") = (num); \
register long _arg1 asm("rdi") = (long)(arg1); \
register long _arg2 asm("rsi") = (long)(arg2); \
register long _arg3 asm("rdx") = (long)(arg3); \
register long _arg4 asm("r10") = (long)(arg4); \
register long _arg5 asm("r8") = (long)(arg5); \
\
asm volatile ( \
"syscall\n" \
: "=a"(_ret) \
: "r"(_arg1), "r"(_arg2), "r"(_arg3), "r"(_arg4), "r"(_arg5), \
"0"(_num) \
: "rcx", "r11", "memory", "cc" \
); \
_ret; \
})
#define my_syscall6(num, arg1, arg2, arg3, arg4, arg5, arg6) \
({ \
long _ret; \
register long _num asm("rax") = (num); \
register long _arg1 asm("rdi") = (long)(arg1); \
register long _arg2 asm("rsi") = (long)(arg2); \
register long _arg3 asm("rdx") = (long)(arg3); \
register long _arg4 asm("r10") = (long)(arg4); \
register long _arg5 asm("r8") = (long)(arg5); \
register long _arg6 asm("r9") = (long)(arg6); \
\
asm volatile ( \
"syscall\n" \
: "=a"(_ret) \
: "r"(_arg1), "r"(_arg2), "r"(_arg3), "r"(_arg4), "r"(_arg5), \
"r"(_arg6), "0"(_num) \
: "rcx", "r11", "memory", "cc" \
); \
_ret; \
})
/* startup code */
/*
* x86-64 System V ABI mandates:
* 1) %rsp must be 16-byte aligned right before the function call.
* 2) The deepest stack frame should be zero (the %rbp).
*
*/
asm(".section .text\n"
".global _start\n"
"_start:\n"
"pop %rdi\n" // argc (first arg, %rdi)
"mov %rsp, %rsi\n" // argv[] (second arg, %rsi)
"lea 8(%rsi,%rdi,8),%rdx\n" // then a NULL then envp (third arg, %rdx)
"xor %ebp, %ebp\n" // zero the stack frame
"and $-16, %rsp\n" // x86 ABI : esp must be 16-byte aligned before call
"call main\n" // main() returns the status code, we'll exit with it.
"mov %eax, %edi\n" // retrieve exit code (32 bit)
"mov $60, %eax\n" // NR_exit == 60
"syscall\n" // really exit
"hlt\n" // ensure it does not return
"");
/* fcntl / open */
#define O_RDONLY 0
#define O_WRONLY 1
#define O_RDWR 2
#define O_CREAT 0x40
#define O_EXCL 0x80
#define O_NOCTTY 0x100
#define O_TRUNC 0x200
#define O_APPEND 0x400
#define O_NONBLOCK 0x800
#define O_DIRECTORY 0x10000
/* The struct returned by the stat() syscall, equivalent to stat64(). The
* syscall returns 116 bytes and stops in the middle of __unused.
*/
struct sys_stat_struct {
unsigned long st_dev;
unsigned long st_ino;
unsigned long st_nlink;
unsigned int st_mode;
unsigned int st_uid;
unsigned int st_gid;
unsigned int __pad0;
unsigned long st_rdev;
long st_size;
long st_blksize;
long st_blocks;
unsigned long st_atime;
unsigned long st_atime_nsec;
unsigned long st_mtime;
unsigned long st_mtime_nsec;
unsigned long st_ctime;
unsigned long st_ctime_nsec;
long __unused[3];
};
#elif defined(__i386__) || defined(__i486__) || defined(__i586__) || defined(__i686__)
/* Syscalls for i386 :
* - mostly similar to x86_64
* - registers are 32-bit
* - syscall number is passed in eax
* - arguments are in ebx, ecx, edx, esi, edi, ebp respectively
* - all registers are preserved (except eax of course)
* - the system call is performed by calling int $0x80
* - syscall return comes in eax
* - the arguments are cast to long and assigned into the target registers
* which are then simply passed as registers to the asm code, so that we
* don't have to experience issues with register constraints.
* - the syscall number is always specified last in order to allow to force
* some registers before (gcc refuses a %-register at the last position).
*
* Also, i386 supports the old_select syscall if newselect is not available
*/
#define __ARCH_WANT_SYS_OLD_SELECT
#define my_syscall0(num) \
({ \
long _ret; \
register long _num asm("eax") = (num); \
\
asm volatile ( \
"int $0x80\n" \
: "=a" (_ret) \
: "0"(_num) \
: "memory", "cc" \
); \
_ret; \
})
#define my_syscall1(num, arg1) \
({ \
long _ret; \
register long _num asm("eax") = (num); \
register long _arg1 asm("ebx") = (long)(arg1); \
\
asm volatile ( \
"int $0x80\n" \
: "=a" (_ret) \
: "r"(_arg1), \
"0"(_num) \
: "memory", "cc" \
); \
_ret; \
})
#define my_syscall2(num, arg1, arg2) \
({ \
long _ret; \
register long _num asm("eax") = (num); \
register long _arg1 asm("ebx") = (long)(arg1); \
register long _arg2 asm("ecx") = (long)(arg2); \
\
asm volatile ( \
"int $0x80\n" \
: "=a" (_ret) \
: "r"(_arg1), "r"(_arg2), \
"0"(_num) \
: "memory", "cc" \
); \
_ret; \
})
#define my_syscall3(num, arg1, arg2, arg3) \
({ \
long _ret; \
register long _num asm("eax") = (num); \
register long _arg1 asm("ebx") = (long)(arg1); \
register long _arg2 asm("ecx") = (long)(arg2); \
register long _arg3 asm("edx") = (long)(arg3); \
\
asm volatile ( \
"int $0x80\n" \
: "=a" (_ret) \
: "r"(_arg1), "r"(_arg2), "r"(_arg3), \
"0"(_num) \
: "memory", "cc" \
); \
_ret; \
})
#define my_syscall4(num, arg1, arg2, arg3, arg4) \
({ \
long _ret; \
register long _num asm("eax") = (num); \
register long _arg1 asm("ebx") = (long)(arg1); \
register long _arg2 asm("ecx") = (long)(arg2); \
register long _arg3 asm("edx") = (long)(arg3); \
register long _arg4 asm("esi") = (long)(arg4); \
\
asm volatile ( \
"int $0x80\n" \
: "=a" (_ret) \
: "r"(_arg1), "r"(_arg2), "r"(_arg3), "r"(_arg4), \
"0"(_num) \
: "memory", "cc" \
); \
_ret; \
})
#define my_syscall5(num, arg1, arg2, arg3, arg4, arg5) \
({ \
long _ret; \
register long _num asm("eax") = (num); \
register long _arg1 asm("ebx") = (long)(arg1); \
register long _arg2 asm("ecx") = (long)(arg2); \
register long _arg3 asm("edx") = (long)(arg3); \
register long _arg4 asm("esi") = (long)(arg4); \
register long _arg5 asm("edi") = (long)(arg5); \
\
asm volatile ( \
"int $0x80\n" \
: "=a" (_ret) \
: "r"(_arg1), "r"(_arg2), "r"(_arg3), "r"(_arg4), "r"(_arg5), \
"0"(_num) \
: "memory", "cc" \
); \
_ret; \
})
/* startup code */
/*
* i386 System V ABI mandates:
* 1) last pushed argument must be 16-byte aligned.
* 2) The deepest stack frame should be set to zero
*
*/
asm(".section .text\n"
".global _start\n"
"_start:\n"
"pop %eax\n" // argc (first arg, %eax)
"mov %esp, %ebx\n" // argv[] (second arg, %ebx)
"lea 4(%ebx,%eax,4),%ecx\n" // then a NULL then envp (third arg, %ecx)
"xor %ebp, %ebp\n" // zero the stack frame
"and $-16, %esp\n" // x86 ABI : esp must be 16-byte aligned before
"sub $4, %esp\n" // the call instruction (args are aligned)
"push %ecx\n" // push all registers on the stack so that we
"push %ebx\n" // support both regparm and plain stack modes
"push %eax\n"
"call main\n" // main() returns the status code in %eax
"mov %eax, %ebx\n" // retrieve exit code (32-bit int)
"movl $1, %eax\n" // NR_exit == 1
"int $0x80\n" // exit now
"hlt\n" // ensure it does not
"");
/* fcntl / open */
#define O_RDONLY 0
#define O_WRONLY 1
#define O_RDWR 2
#define O_CREAT 0x40
#define O_EXCL 0x80
#define O_NOCTTY 0x100
#define O_TRUNC 0x200
#define O_APPEND 0x400
#define O_NONBLOCK 0x800
#define O_DIRECTORY 0x10000
/* The struct returned by the stat() syscall, 32-bit only, the syscall returns
* exactly 56 bytes (stops before the unused array).
*/
struct sys_stat_struct {
unsigned long st_dev;
unsigned long st_ino;
unsigned short st_mode;
unsigned short st_nlink;
unsigned short st_uid;
unsigned short st_gid;
unsigned long st_rdev;
unsigned long st_size;
unsigned long st_blksize;
unsigned long st_blocks;
unsigned long st_atime;
unsigned long st_atime_nsec;
unsigned long st_mtime;
unsigned long st_mtime_nsec;
unsigned long st_ctime;
unsigned long st_ctime_nsec;
unsigned long __unused[2];
};
#elif defined(__ARM_EABI__)
/* Syscalls for ARM in ARM or Thumb modes :
* - registers are 32-bit
* - stack is 8-byte aligned
* ( http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.faqs/ka4127.html)
* - syscall number is passed in r7
* - arguments are in r0, r1, r2, r3, r4, r5
* - the system call is performed by calling svc #0
* - syscall return comes in r0.
* - only lr is clobbered.
* - the arguments are cast to long and assigned into the target registers
* which are then simply passed as registers to the asm code, so that we
* don't have to experience issues with register constraints.
* - the syscall number is always specified last in order to allow to force
* some registers before (gcc refuses a %-register at the last position).
*
* Also, ARM supports the old_select syscall if newselect is not available
*/
#define __ARCH_WANT_SYS_OLD_SELECT
#define my_syscall0(num) \
({ \
register long _num asm("r7") = (num); \
register long _arg1 asm("r0"); \
\
asm volatile ( \
"svc #0\n" \
: "=r"(_arg1) \
: "r"(_num) \
: "memory", "cc", "lr" \
); \
_arg1; \
})
#define my_syscall1(num, arg1) \
({ \
register long _num asm("r7") = (num); \
register long _arg1 asm("r0") = (long)(arg1); \
\
asm volatile ( \
"svc #0\n" \
: "=r"(_arg1) \
: "r"(_arg1), \
"r"(_num) \
: "memory", "cc", "lr" \
); \
_arg1; \
})
#define my_syscall2(num, arg1, arg2) \
({ \
register long _num asm("r7") = (num); \
register long _arg1 asm("r0") = (long)(arg1); \
register long _arg2 asm("r1") = (long)(arg2); \
\
asm volatile ( \
"svc #0\n" \
: "=r"(_arg1) \
: "r"(_arg1), "r"(_arg2), \
"r"(_num) \
: "memory", "cc", "lr" \
); \
_arg1; \
})
#define my_syscall3(num, arg1, arg2, arg3) \
({ \
register long _num asm("r7") = (num); \
register long _arg1 asm("r0") = (long)(arg1); \
register long _arg2 asm("r1") = (long)(arg2); \
register long _arg3 asm("r2") = (long)(arg3); \
\
asm volatile ( \
"svc #0\n" \
: "=r"(_arg1) \
: "r"(_arg1), "r"(_arg2), "r"(_arg3), \
"r"(_num) \
: "memory", "cc", "lr" \
); \
_arg1; \
})
#define my_syscall4(num, arg1, arg2, arg3, arg4) \
({ \
register long _num asm("r7") = (num); \
register long _arg1 asm("r0") = (long)(arg1); \
register long _arg2 asm("r1") = (long)(arg2); \
register long _arg3 asm("r2") = (long)(arg3); \
register long _arg4 asm("r3") = (long)(arg4); \
\
asm volatile ( \
"svc #0\n" \
: "=r"(_arg1) \
: "r"(_arg1), "r"(_arg2), "r"(_arg3), "r"(_arg4), \
"r"(_num) \
: "memory", "cc", "lr" \
); \
_arg1; \
})
#define my_syscall5(num, arg1, arg2, arg3, arg4, arg5) \
({ \
register long _num asm("r7") = (num); \
register long _arg1 asm("r0") = (long)(arg1); \
register long _arg2 asm("r1") = (long)(arg2); \
register long _arg3 asm("r2") = (long)(arg3); \
register long _arg4 asm("r3") = (long)(arg4); \
register long _arg5 asm("r4") = (long)(arg5); \
\
asm volatile ( \
"svc #0\n" \
: "=r" (_arg1) \
: "r"(_arg1), "r"(_arg2), "r"(_arg3), "r"(_arg4), "r"(_arg5), \
"r"(_num) \
: "memory", "cc", "lr" \
); \
_arg1; \
})
/* startup code */
asm(".section .text\n"
".global _start\n"
"_start:\n"
#if defined(__THUMBEB__) || defined(__THUMBEL__)
/* We enter here in 32-bit mode but if some previous functions were in
* 16-bit mode, the assembler cannot know, so we need to tell it we're in
* 32-bit now, then switch to 16-bit (is there a better way to do it than
* adding 1 by hand ?) and tell the asm we're now in 16-bit mode so that
* it generates correct instructions. Note that we do not support thumb1.
*/
".code 32\n"
"add r0, pc, #1\n"
"bx r0\n"
".code 16\n"
#endif
"pop {%r0}\n" // argc was in the stack
"mov %r1, %sp\n" // argv = sp
"add %r2, %r1, %r0, lsl #2\n" // envp = argv + 4*argc ...
"add %r2, %r2, $4\n" // ... + 4
"and %r3, %r1, $-8\n" // AAPCS : sp must be 8-byte aligned in the
"mov %sp, %r3\n" // callee, an bl doesn't push (lr=pc)
"bl main\n" // main() returns the status code, we'll exit with it.
"movs r7, $1\n" // NR_exit == 1
"svc $0x00\n"
"");
/* fcntl / open */
#define O_RDONLY 0
#define O_WRONLY 1
#define O_RDWR 2
#define O_CREAT 0x40
#define O_EXCL 0x80
#define O_NOCTTY 0x100
#define O_TRUNC 0x200
#define O_APPEND 0x400
#define O_NONBLOCK 0x800
#define O_DIRECTORY 0x4000
/* The struct returned by the stat() syscall, 32-bit only, the syscall returns
* exactly 56 bytes (stops before the unused array). In big endian, the format
* differs as devices are returned as short only.
*/
struct sys_stat_struct {
#if defined(__ARMEB__)
unsigned short st_dev;
unsigned short __pad1;
#else
unsigned long st_dev;
#endif
unsigned long st_ino;
unsigned short st_mode;
unsigned short st_nlink;
unsigned short st_uid;
unsigned short st_gid;
#if defined(__ARMEB__)
unsigned short st_rdev;
unsigned short __pad2;
#else
unsigned long st_rdev;
#endif
unsigned long st_size;
unsigned long st_blksize;
unsigned long st_blocks;
unsigned long st_atime;
unsigned long st_atime_nsec;
unsigned long st_mtime;
unsigned long st_mtime_nsec;
unsigned long st_ctime;
unsigned long st_ctime_nsec;
unsigned long __unused[2];
};
#elif defined(__aarch64__)
/* Syscalls for AARCH64 :
* - registers are 64-bit
* - stack is 16-byte aligned
* - syscall number is passed in x8
* - arguments are in x0, x1, x2, x3, x4, x5
* - the system call is performed by calling svc 0
* - syscall return comes in x0.
* - the arguments are cast to long and assigned into the target registers
* which are then simply passed as registers to the asm code, so that we
* don't have to experience issues with register constraints.
*
* On aarch64, select() is not implemented so we have to use pselect6().
*/
#define __ARCH_WANT_SYS_PSELECT6
#define my_syscall0(num) \
({ \
register long _num asm("x8") = (num); \
register long _arg1 asm("x0"); \
\
asm volatile ( \
"svc #0\n" \
: "=r"(_arg1) \
: "r"(_num) \
: "memory", "cc" \
); \
_arg1; \
})
#define my_syscall1(num, arg1) \
({ \
register long _num asm("x8") = (num); \
register long _arg1 asm("x0") = (long)(arg1); \
\
asm volatile ( \
"svc #0\n" \
: "=r"(_arg1) \
: "r"(_arg1), \
"r"(_num) \
: "memory", "cc" \
); \
_arg1; \
})
#define my_syscall2(num, arg1, arg2) \
({ \
register long _num asm("x8") = (num); \
register long _arg1 asm("x0") = (long)(arg1); \
register long _arg2 asm("x1") = (long)(arg2); \
\
asm volatile ( \
"svc #0\n" \
: "=r"(_arg1) \
: "r"(_arg1), "r"(_arg2), \
"r"(_num) \
: "memory", "cc" \
); \
_arg1; \
})
#define my_syscall3(num, arg1, arg2, arg3) \
({ \
register long _num asm("x8") = (num); \
register long _arg1 asm("x0") = (long)(arg1); \
register long _arg2 asm("x1") = (long)(arg2); \
register long _arg3 asm("x2") = (long)(arg3); \
\
asm volatile ( \
"svc #0\n" \
: "=r"(_arg1) \
: "r"(_arg1), "r"(_arg2), "r"(_arg3), \
"r"(_num) \
: "memory", "cc" \
); \
_arg1; \
})
#define my_syscall4(num, arg1, arg2, arg3, arg4) \
({ \
register long _num asm("x8") = (num); \
register long _arg1 asm("x0") = (long)(arg1); \
register long _arg2 asm("x1") = (long)(arg2); \
register long _arg3 asm("x2") = (long)(arg3); \
register long _arg4 asm("x3") = (long)(arg4); \
\
asm volatile ( \
"svc #0\n" \
: "=r"(_arg1) \
: "r"(_arg1), "r"(_arg2), "r"(_arg3), "r"(_arg4), \
"r"(_num) \
: "memory", "cc" \
); \
_arg1; \
})
#define my_syscall5(num, arg1, arg2, arg3, arg4, arg5) \
({ \
register long _num asm("x8") = (num); \
register long _arg1 asm("x0") = (long)(arg1); \
register long _arg2 asm("x1") = (long)(arg2); \
register long _arg3 asm("x2") = (long)(arg3); \
register long _arg4 asm("x3") = (long)(arg4); \
register long _arg5 asm("x4") = (long)(arg5); \
\
asm volatile ( \
"svc #0\n" \
: "=r" (_arg1) \
: "r"(_arg1), "r"(_arg2), "r"(_arg3), "r"(_arg4), "r"(_arg5), \
"r"(_num) \
: "memory", "cc" \
); \
_arg1; \
})
#define my_syscall6(num, arg1, arg2, arg3, arg4, arg5, arg6) \
({ \
register long _num asm("x8") = (num); \
register long _arg1 asm("x0") = (long)(arg1); \
register long _arg2 asm("x1") = (long)(arg2); \
register long _arg3 asm("x2") = (long)(arg3); \
register long _arg4 asm("x3") = (long)(arg4); \
register long _arg5 asm("x4") = (long)(arg5); \
register long _arg6 asm("x5") = (long)(arg6); \
\
asm volatile ( \
"svc #0\n" \
: "=r" (_arg1) \
: "r"(_arg1), "r"(_arg2), "r"(_arg3), "r"(_arg4), "r"(_arg5), \
"r"(_arg6), "r"(_num) \
: "memory", "cc" \
); \
_arg1; \
})
/* startup code */
asm(".section .text\n"
".global _start\n"
"_start:\n"
"ldr x0, [sp]\n" // argc (x0) was in the stack
"add x1, sp, 8\n" // argv (x1) = sp
"lsl x2, x0, 3\n" // envp (x2) = 8*argc ...
"add x2, x2, 8\n" // + 8 (skip null)
"add x2, x2, x1\n" // + argv
"and sp, x1, -16\n" // sp must be 16-byte aligned in the callee
"bl main\n" // main() returns the status code, we'll exit with it.
"mov x8, 93\n" // NR_exit == 93
"svc #0\n"
"");
/* fcntl / open */
#define O_RDONLY 0
#define O_WRONLY 1
#define O_RDWR 2
#define O_CREAT 0x40
#define O_EXCL 0x80
#define O_NOCTTY 0x100
#define O_TRUNC 0x200
#define O_APPEND 0x400
#define O_NONBLOCK 0x800
#define O_DIRECTORY 0x4000
/* The struct returned by the newfstatat() syscall. Differs slightly from the
* x86_64's stat one by field ordering, so be careful.
*/
struct sys_stat_struct {
unsigned long st_dev;
unsigned long st_ino;
unsigned int st_mode;
unsigned int st_nlink;
unsigned int st_uid;
unsigned int st_gid;
unsigned long st_rdev;
unsigned long __pad1;
long st_size;
int st_blksize;
int __pad2;
long st_blocks;
long st_atime;
unsigned long st_atime_nsec;
long st_mtime;
unsigned long st_mtime_nsec;
long st_ctime;
unsigned long st_ctime_nsec;
unsigned int __unused[2];
};
#elif defined(__mips__) && defined(_ABIO32)
/* Syscalls for MIPS ABI O32 :
* - WARNING! there's always a delayed slot!
* - WARNING again, the syntax is different, registers take a '$' and numbers
* do not.
* - registers are 32-bit
* - stack is 8-byte aligned
* - syscall number is passed in v0 (starts at 0xfa0).
* - arguments are in a0, a1, a2, a3, then the stack. The caller needs to
* leave some room in the stack for the callee to save a0..a3 if needed.
* - Many registers are clobbered, in fact only a0..a2 and s0..s8 are
* preserved. See: https://www.linux-mips.org/wiki/Syscall as well as
* scall32-o32.S in the kernel sources.
* - the system call is performed by calling "syscall"
* - syscall return comes in v0, and register a3 needs to be checked to know
* if an error occurred, in which case errno is in v0.
* - the arguments are cast to long and assigned into the target registers
* which are then simply passed as registers to the asm code, so that we
* don't have to experience issues with register constraints.
*/
#define my_syscall0(num) \
({ \
register long _num asm("v0") = (num); \
register long _arg4 asm("a3"); \
\
asm volatile ( \
"addiu $sp, $sp, -32\n" \
"syscall\n" \
"addiu $sp, $sp, 32\n" \
: "=r"(_num), "=r"(_arg4) \
: "r"(_num) \
: "memory", "cc", "at", "v1", "hi", "lo", \
"t0", "t1", "t2", "t3", "t4", "t5", "t6", "t7", "t8", "t9" \
); \
_arg4 ? -_num : _num; \
})
#define my_syscall1(num, arg1) \
({ \
register long _num asm("v0") = (num); \
register long _arg1 asm("a0") = (long)(arg1); \
register long _arg4 asm("a3"); \
\
asm volatile ( \
"addiu $sp, $sp, -32\n" \
"syscall\n" \
"addiu $sp, $sp, 32\n" \
: "=r"(_num), "=r"(_arg4) \
: "0"(_num), \
"r"(_arg1) \
: "memory", "cc", "at", "v1", "hi", "lo", \
"t0", "t1", "t2", "t3", "t4", "t5", "t6", "t7", "t8", "t9" \
); \
_arg4 ? -_num : _num; \
})
#define my_syscall2(num, arg1, arg2) \
({ \
register long _num asm("v0") = (num); \
register long _arg1 asm("a0") = (long)(arg1); \
register long _arg2 asm("a1") = (long)(arg2); \
register long _arg4 asm("a3"); \
\
asm volatile ( \
"addiu $sp, $sp, -32\n" \
"syscall\n" \
"addiu $sp, $sp, 32\n" \
: "=r"(_num), "=r"(_arg4) \
: "0"(_num), \
"r"(_arg1), "r"(_arg2) \
: "memory", "cc", "at", "v1", "hi", "lo", \
"t0", "t1", "t2", "t3", "t4", "t5", "t6", "t7", "t8", "t9" \
); \
_arg4 ? -_num : _num; \
})
#define my_syscall3(num, arg1, arg2, arg3) \
({ \
register long _num asm("v0") = (num); \
register long _arg1 asm("a0") = (long)(arg1); \
register long _arg2 asm("a1") = (long)(arg2); \
register long _arg3 asm("a2") = (long)(arg3); \
register long _arg4 asm("a3"); \
\
asm volatile ( \
"addiu $sp, $sp, -32\n" \
"syscall\n" \
"addiu $sp, $sp, 32\n" \
: "=r"(_num), "=r"(_arg4) \
: "0"(_num), \
"r"(_arg1), "r"(_arg2), "r"(_arg3) \
: "memory", "cc", "at", "v1", "hi", "lo", \
"t0", "t1", "t2", "t3", "t4", "t5", "t6", "t7", "t8", "t9" \
); \
_arg4 ? -_num : _num; \
})
#define my_syscall4(num, arg1, arg2, arg3, arg4) \
({ \
register long _num asm("v0") = (num); \
register long _arg1 asm("a0") = (long)(arg1); \
register long _arg2 asm("a1") = (long)(arg2); \
register long _arg3 asm("a2") = (long)(arg3); \
register long _arg4 asm("a3") = (long)(arg4); \
\
asm volatile ( \
"addiu $sp, $sp, -32\n" \
"syscall\n" \
"addiu $sp, $sp, 32\n" \
: "=r" (_num), "=r"(_arg4) \
: "0"(_num), \
"r"(_arg1), "r"(_arg2), "r"(_arg3), "r"(_arg4) \
: "memory", "cc", "at", "v1", "hi", "lo", \
"t0", "t1", "t2", "t3", "t4", "t5", "t6", "t7", "t8", "t9" \
); \
_arg4 ? -_num : _num; \
})
#define my_syscall5(num, arg1, arg2, arg3, arg4, arg5) \
({ \
register long _num asm("v0") = (num); \
register long _arg1 asm("a0") = (long)(arg1); \
register long _arg2 asm("a1") = (long)(arg2); \
register long _arg3 asm("a2") = (long)(arg3); \
register long _arg4 asm("a3") = (long)(arg4); \
register long _arg5 = (long)(arg5); \
\
asm volatile ( \
"addiu $sp, $sp, -32\n" \
"sw %7, 16($sp)\n" \
"syscall\n " \
"addiu $sp, $sp, 32\n" \
: "=r" (_num), "=r"(_arg4) \
: "0"(_num), \
"r"(_arg1), "r"(_arg2), "r"(_arg3), "r"(_arg4), "r"(_arg5) \
: "memory", "cc", "at", "v1", "hi", "lo", \
"t0", "t1", "t2", "t3", "t4", "t5", "t6", "t7", "t8", "t9" \
); \
_arg4 ? -_num : _num; \
})
/* startup code, note that it's called __start on MIPS */
asm(".section .text\n"
".set nomips16\n"
".global __start\n"
".set noreorder\n"
".option pic0\n"
".ent __start\n"
"__start:\n"
"lw $a0,($sp)\n" // argc was in the stack
"addiu $a1, $sp, 4\n" // argv = sp + 4
"sll $a2, $a0, 2\n" // a2 = argc * 4
"add $a2, $a2, $a1\n" // envp = argv + 4*argc ...
"addiu $a2, $a2, 4\n" // ... + 4
"li $t0, -8\n"
"and $sp, $sp, $t0\n" // sp must be 8-byte aligned
"addiu $sp,$sp,-16\n" // the callee expects to save a0..a3 there!
"jal main\n" // main() returns the status code, we'll exit with it.
"nop\n" // delayed slot
"move $a0, $v0\n" // retrieve 32-bit exit code from v0
"li $v0, 4001\n" // NR_exit == 4001
"syscall\n"
".end __start\n"
"");
/* fcntl / open */
#define O_RDONLY 0
#define O_WRONLY 1
#define O_RDWR 2
#define O_APPEND 0x0008
#define O_NONBLOCK 0x0080
#define O_CREAT 0x0100
#define O_TRUNC 0x0200
#define O_EXCL 0x0400
#define O_NOCTTY 0x0800
#define O_DIRECTORY 0x10000
/* The struct returned by the stat() syscall. 88 bytes are returned by the
* syscall.
*/
struct sys_stat_struct {
unsigned int st_dev;
long st_pad1[3];
unsigned long st_ino;
unsigned int st_mode;
unsigned int st_nlink;
unsigned int st_uid;
unsigned int st_gid;
unsigned int st_rdev;
long st_pad2[2];
long st_size;
long st_pad3;
long st_atime;
long st_atime_nsec;
long st_mtime;
long st_mtime_nsec;
long st_ctime;
long st_ctime_nsec;
long st_blksize;
long st_blocks;
long st_pad4[14];
};
#elif defined(__riscv)
#if __riscv_xlen == 64
#define PTRLOG "3"
#define SZREG "8"
#elif __riscv_xlen == 32
#define PTRLOG "2"
#define SZREG "4"
#endif
/* Syscalls for RISCV :
* - stack is 16-byte aligned
* - syscall number is passed in a7
* - arguments are in a0, a1, a2, a3, a4, a5
* - the system call is performed by calling ecall
* - syscall return comes in a0
* - the arguments are cast to long and assigned into the target
* registers which are then simply passed as registers to the asm code,
* so that we don't have to experience issues with register constraints.
*/
#define my_syscall0(num) \
({ \
register long _num asm("a7") = (num); \
register long _arg1 asm("a0"); \
\
asm volatile ( \
"ecall\n\t" \
: "=r"(_arg1) \
: "r"(_num) \
: "memory", "cc" \
); \
_arg1; \
})
#define my_syscall1(num, arg1) \
({ \
register long _num asm("a7") = (num); \
register long _arg1 asm("a0") = (long)(arg1); \
\
asm volatile ( \
"ecall\n" \
: "+r"(_arg1) \
: "r"(_num) \
: "memory", "cc" \
); \
_arg1; \
})
#define my_syscall2(num, arg1, arg2) \
({ \
register long _num asm("a7") = (num); \
register long _arg1 asm("a0") = (long)(arg1); \
register long _arg2 asm("a1") = (long)(arg2); \
\
asm volatile ( \
"ecall\n" \
: "+r"(_arg1) \
: "r"(_arg2), \
"r"(_num) \
: "memory", "cc" \
); \
_arg1; \
})
#define my_syscall3(num, arg1, arg2, arg3) \
({ \
register long _num asm("a7") = (num); \
register long _arg1 asm("a0") = (long)(arg1); \
register long _arg2 asm("a1") = (long)(arg2); \
register long _arg3 asm("a2") = (long)(arg3); \
\
asm volatile ( \
"ecall\n\t" \
: "+r"(_arg1) \
: "r"(_arg2), "r"(_arg3), \
"r"(_num) \
: "memory", "cc" \
); \
_arg1; \
})
#define my_syscall4(num, arg1, arg2, arg3, arg4) \
({ \
register long _num asm("a7") = (num); \
register long _arg1 asm("a0") = (long)(arg1); \
register long _arg2 asm("a1") = (long)(arg2); \
register long _arg3 asm("a2") = (long)(arg3); \
register long _arg4 asm("a3") = (long)(arg4); \
\
asm volatile ( \
"ecall\n" \
: "+r"(_arg1) \
: "r"(_arg2), "r"(_arg3), "r"(_arg4), \
"r"(_num) \
: "memory", "cc" \
); \
_arg1; \
})
#define my_syscall5(num, arg1, arg2, arg3, arg4, arg5) \
({ \
register long _num asm("a7") = (num); \
register long _arg1 asm("a0") = (long)(arg1); \
register long _arg2 asm("a1") = (long)(arg2); \
register long _arg3 asm("a2") = (long)(arg3); \
register long _arg4 asm("a3") = (long)(arg4); \
register long _arg5 asm("a4") = (long)(arg5); \
\
asm volatile ( \
"ecall\n" \
: "+r"(_arg1) \
: "r"(_arg2), "r"(_arg3), "r"(_arg4), "r"(_arg5), \
"r"(_num) \
: "memory", "cc" \
); \
_arg1; \
})
#define my_syscall6(num, arg1, arg2, arg3, arg4, arg5, arg6) \
({ \
register long _num asm("a7") = (num); \
register long _arg1 asm("a0") = (long)(arg1); \
register long _arg2 asm("a1") = (long)(arg2); \
register long _arg3 asm("a2") = (long)(arg3); \
register long _arg4 asm("a3") = (long)(arg4); \
register long _arg5 asm("a4") = (long)(arg5); \
register long _arg6 asm("a5") = (long)(arg6); \
\
asm volatile ( \
"ecall\n" \
: "+r"(_arg1) \
: "r"(_arg2), "r"(_arg3), "r"(_arg4), "r"(_arg5), "r"(_arg6), \
"r"(_num) \
: "memory", "cc" \
); \
_arg1; \
})
/* startup code */
asm(".section .text\n"
".global _start\n"
"_start:\n"
".option push\n"
".option norelax\n"
"lla gp, __global_pointer$\n"
".option pop\n"
"ld a0, 0(sp)\n" // argc (a0) was in the stack
"add a1, sp, "SZREG"\n" // argv (a1) = sp
"slli a2, a0, "PTRLOG"\n" // envp (a2) = SZREG*argc ...
"add a2, a2, "SZREG"\n" // + SZREG (skip null)
"add a2,a2,a1\n" // + argv
"andi sp,a1,-16\n" // sp must be 16-byte aligned
"call main\n" // main() returns the status code, we'll exit with it.
"li a7, 93\n" // NR_exit == 93
"ecall\n"
"");
/* fcntl / open */
#define O_RDONLY 0
#define O_WRONLY 1
#define O_RDWR 2
#define O_CREAT 0x100
#define O_EXCL 0x200
#define O_NOCTTY 0x400
#define O_TRUNC 0x1000
#define O_APPEND 0x2000
#define O_NONBLOCK 0x4000
#define O_DIRECTORY 0x200000
struct sys_stat_struct {
unsigned long st_dev; /* Device. */
unsigned long st_ino; /* File serial number. */
unsigned int st_mode; /* File mode. */
unsigned int st_nlink; /* Link count. */
unsigned int st_uid; /* User ID of the file's owner. */
unsigned int st_gid; /* Group ID of the file's group. */
unsigned long st_rdev; /* Device number, if device. */
unsigned long __pad1;
long st_size; /* Size of file, in bytes. */
int st_blksize; /* Optimal block size for I/O. */
int __pad2;
long st_blocks; /* Number 512-byte blocks allocated. */
long st_atime; /* Time of last access. */
unsigned long st_atime_nsec;
long st_mtime; /* Time of last modification. */
unsigned long st_mtime_nsec;
long st_ctime; /* Time of last status change. */
unsigned long st_ctime_nsec;
unsigned int __unused4;
unsigned int __unused5;
};
#endif
/* Below are the C functions used to declare the raw syscalls. They try to be
* architecture-agnostic, and return either a success or -errno. Declaring them
* static will lead to them being inlined in most cases, but it's still possible
* to reference them by a pointer if needed.
*/
static __attribute__((unused))
void *sys_brk(void *addr)
{
return (void *)my_syscall1(__NR_brk, addr);
}
static __attribute__((noreturn,unused))
void sys_exit(int status)
{
my_syscall1(__NR_exit, status & 255);
while(1); // shut the "noreturn" warnings.
}
static __attribute__((unused))
int sys_chdir(const char *path)
{
return my_syscall1(__NR_chdir, path);
}
static __attribute__((unused))
int sys_chmod(const char *path, mode_t mode)
{
#ifdef __NR_fchmodat
return my_syscall4(__NR_fchmodat, AT_FDCWD, path, mode, 0);
#elif defined(__NR_chmod)
return my_syscall2(__NR_chmod, path, mode);
#else
#error Neither __NR_fchmodat nor __NR_chmod defined, cannot implement sys_chmod()
#endif
}
static __attribute__((unused))
int sys_chown(const char *path, uid_t owner, gid_t group)
{
#ifdef __NR_fchownat
return my_syscall5(__NR_fchownat, AT_FDCWD, path, owner, group, 0);
#elif defined(__NR_chown)
return my_syscall3(__NR_chown, path, owner, group);
#else
#error Neither __NR_fchownat nor __NR_chown defined, cannot implement sys_chown()
#endif
}
static __attribute__((unused))
int sys_chroot(const char *path)
{
return my_syscall1(__NR_chroot, path);
}
static __attribute__((unused))
int sys_close(int fd)
{
return my_syscall1(__NR_close, fd);
}
static __attribute__((unused))
int sys_dup(int fd)
{
return my_syscall1(__NR_dup, fd);
}
#ifdef __NR_dup3
static __attribute__((unused))
int sys_dup3(int old, int new, int flags)
{
return my_syscall3(__NR_dup3, old, new, flags);
}
#endif
static __attribute__((unused))
int sys_dup2(int old, int new)
{
#ifdef __NR_dup3
return my_syscall3(__NR_dup3, old, new, 0);
#elif defined(__NR_dup2)
return my_syscall2(__NR_dup2, old, new);
#else
#error Neither __NR_dup3 nor __NR_dup2 defined, cannot implement sys_dup2()
#endif
}
static __attribute__((unused))
int sys_execve(const char *filename, char *const argv[], char *const envp[])
{
return my_syscall3(__NR_execve, filename, argv, envp);
}
static __attribute__((unused))
pid_t sys_fork(void)
{
#ifdef __NR_clone
/* note: some archs only have clone() and not fork(). Different archs
* have a different API, but most archs have the flags on first arg and
* will not use the rest with no other flag.
*/
return my_syscall5(__NR_clone, SIGCHLD, 0, 0, 0, 0);
#elif defined(__NR_fork)
return my_syscall0(__NR_fork);
#else
#error Neither __NR_clone nor __NR_fork defined, cannot implement sys_fork()
#endif
}
static __attribute__((unused))
int sys_fsync(int fd)
{
return my_syscall1(__NR_fsync, fd);
}
static __attribute__((unused))
int sys_getdents64(int fd, struct linux_dirent64 *dirp, int count)
{
return my_syscall3(__NR_getdents64, fd, dirp, count);
}
static __attribute__((unused))
pid_t sys_getpgid(pid_t pid)
{
return my_syscall1(__NR_getpgid, pid);
}
static __attribute__((unused))
pid_t sys_getpgrp(void)
{
return sys_getpgid(0);
}
static __attribute__((unused))
pid_t sys_getpid(void)
{
return my_syscall0(__NR_getpid);
}
static __attribute__((unused))
int sys_gettimeofday(struct timeval *tv, struct timezone *tz)
{
return my_syscall2(__NR_gettimeofday, tv, tz);
}
static __attribute__((unused))
int sys_ioctl(int fd, unsigned long req, void *value)
{
return my_syscall3(__NR_ioctl, fd, req, value);
}
static __attribute__((unused))
int sys_kill(pid_t pid, int signal)
{
return my_syscall2(__NR_kill, pid, signal);
}
static __attribute__((unused))
int sys_link(const char *old, const char *new)
{
#ifdef __NR_linkat
return my_syscall5(__NR_linkat, AT_FDCWD, old, AT_FDCWD, new, 0);
#elif defined(__NR_link)
return my_syscall2(__NR_link, old, new);
#else
#error Neither __NR_linkat nor __NR_link defined, cannot implement sys_link()
#endif
}
static __attribute__((unused))
off_t sys_lseek(int fd, off_t offset, int whence)
{
return my_syscall3(__NR_lseek, fd, offset, whence);
}
static __attribute__((unused))
int sys_mkdir(const char *path, mode_t mode)
{
#ifdef __NR_mkdirat
return my_syscall3(__NR_mkdirat, AT_FDCWD, path, mode);
#elif defined(__NR_mkdir)
return my_syscall2(__NR_mkdir, path, mode);
#else
#error Neither __NR_mkdirat nor __NR_mkdir defined, cannot implement sys_mkdir()
#endif
}
static __attribute__((unused))
long sys_mknod(const char *path, mode_t mode, dev_t dev)
{
#ifdef __NR_mknodat
return my_syscall4(__NR_mknodat, AT_FDCWD, path, mode, dev);
#elif defined(__NR_mknod)
return my_syscall3(__NR_mknod, path, mode, dev);
#else
#error Neither __NR_mknodat nor __NR_mknod defined, cannot implement sys_mknod()
#endif
}
static __attribute__((unused))
int sys_mount(const char *src, const char *tgt, const char *fst,
unsigned long flags, const void *data)
{
return my_syscall5(__NR_mount, src, tgt, fst, flags, data);
}
static __attribute__((unused))
int sys_open(const char *path, int flags, mode_t mode)
{
#ifdef __NR_openat
return my_syscall4(__NR_openat, AT_FDCWD, path, flags, mode);
#elif defined(__NR_open)
return my_syscall3(__NR_open, path, flags, mode);
#else
#error Neither __NR_openat nor __NR_open defined, cannot implement sys_open()
#endif
}
static __attribute__((unused))
int sys_pivot_root(const char *new, const char *old)
{
return my_syscall2(__NR_pivot_root, new, old);
}
static __attribute__((unused))
int sys_poll(struct pollfd *fds, int nfds, int timeout)
{
#if defined(__NR_ppoll)
struct timespec t;
if (timeout >= 0) {
t.tv_sec = timeout / 1000;
t.tv_nsec = (timeout % 1000) * 1000000;
}
return my_syscall4(__NR_ppoll, fds, nfds, (timeout >= 0) ? &t : NULL, NULL);
#elif defined(__NR_poll)
return my_syscall3(__NR_poll, fds, nfds, timeout);
#else
#error Neither __NR_ppoll nor __NR_poll defined, cannot implement sys_poll()
#endif
}
static __attribute__((unused))
ssize_t sys_read(int fd, void *buf, size_t count)
{
return my_syscall3(__NR_read, fd, buf, count);
}
static __attribute__((unused))
ssize_t sys_reboot(int magic1, int magic2, int cmd, void *arg)
{
return my_syscall4(__NR_reboot, magic1, magic2, cmd, arg);
}
static __attribute__((unused))
int sys_sched_yield(void)
{
return my_syscall0(__NR_sched_yield);
}
static __attribute__((unused))
int sys_select(int nfds, fd_set *rfds, fd_set *wfds, fd_set *efds, struct timeval *timeout)
{
#if defined(__ARCH_WANT_SYS_OLD_SELECT) && !defined(__NR__newselect)
struct sel_arg_struct {
unsigned long n;
fd_set *r, *w, *e;
struct timeval *t;
} arg = { .n = nfds, .r = rfds, .w = wfds, .e = efds, .t = timeout };
return my_syscall1(__NR_select, &arg);
#elif defined(__ARCH_WANT_SYS_PSELECT6) && defined(__NR_pselect6)
struct timespec t;
if (timeout) {
t.tv_sec = timeout->tv_sec;
t.tv_nsec = timeout->tv_usec * 1000;
}
return my_syscall6(__NR_pselect6, nfds, rfds, wfds, efds, timeout ? &t : NULL, NULL);
#elif defined(__NR__newselect) || defined(__NR_select)
#ifndef __NR__newselect
#define __NR__newselect __NR_select
#endif
return my_syscall5(__NR__newselect, nfds, rfds, wfds, efds, timeout);
#else
#error None of __NR_select, __NR_pselect6, nor __NR__newselect defined, cannot implement sys_select()
#endif
}
static __attribute__((unused))
int sys_setpgid(pid_t pid, pid_t pgid)
{
return my_syscall2(__NR_setpgid, pid, pgid);
}
static __attribute__((unused))
pid_t sys_setsid(void)
{
return my_syscall0(__NR_setsid);
}
static __attribute__((unused))
int sys_stat(const char *path, struct stat *buf)
{
struct sys_stat_struct stat;
long ret;
#ifdef __NR_newfstatat
/* only solution for arm64 */
ret = my_syscall4(__NR_newfstatat, AT_FDCWD, path, &stat, 0);
#elif defined(__NR_stat)
ret = my_syscall2(__NR_stat, path, &stat);
#else
#error Neither __NR_newfstatat nor __NR_stat defined, cannot implement sys_stat()
#endif
buf->st_dev = stat.st_dev;
buf->st_ino = stat.st_ino;
buf->st_mode = stat.st_mode;
buf->st_nlink = stat.st_nlink;
buf->st_uid = stat.st_uid;
buf->st_gid = stat.st_gid;
buf->st_rdev = stat.st_rdev;
buf->st_size = stat.st_size;
buf->st_blksize = stat.st_blksize;
buf->st_blocks = stat.st_blocks;
buf->st_atime = stat.st_atime;
buf->st_mtime = stat.st_mtime;
buf->st_ctime = stat.st_ctime;
return ret;
}
static __attribute__((unused))
int sys_symlink(const char *old, const char *new)
{
#ifdef __NR_symlinkat
return my_syscall3(__NR_symlinkat, old, AT_FDCWD, new);
#elif defined(__NR_symlink)
return my_syscall2(__NR_symlink, old, new);
#else
#error Neither __NR_symlinkat nor __NR_symlink defined, cannot implement sys_symlink()
#endif
}
static __attribute__((unused))
mode_t sys_umask(mode_t mode)
{
return my_syscall1(__NR_umask, mode);
}
static __attribute__((unused))
int sys_umount2(const char *path, int flags)
{
return my_syscall2(__NR_umount2, path, flags);
}
static __attribute__((unused))
int sys_unlink(const char *path)
{
#ifdef __NR_unlinkat
return my_syscall3(__NR_unlinkat, AT_FDCWD, path, 0);
#elif defined(__NR_unlink)
return my_syscall1(__NR_unlink, path);
#else
#error Neither __NR_unlinkat nor __NR_unlink defined, cannot implement sys_unlink()
#endif
}
static __attribute__((unused))
pid_t sys_wait4(pid_t pid, int *status, int options, struct rusage *rusage)
{
return my_syscall4(__NR_wait4, pid, status, options, rusage);
}
static __attribute__((unused))
pid_t sys_waitpid(pid_t pid, int *status, int options)
{
return sys_wait4(pid, status, options, 0);
}
static __attribute__((unused))
pid_t sys_wait(int *status)
{
return sys_waitpid(-1, status, 0);
}
static __attribute__((unused))
ssize_t sys_write(int fd, const void *buf, size_t count)
{
return my_syscall3(__NR_write, fd, buf, count);
}
/* Below are the libc-compatible syscalls which return x or -1 and set errno.
* They rely on the functions above. Similarly they're marked static so that it
* is possible to assign pointers to them if needed.
*/
static __attribute__((unused))
int brk(void *addr)
{
void *ret = sys_brk(addr);
if (!ret) {
SET_ERRNO(ENOMEM);
return -1;
}
return 0;
}
static __attribute__((noreturn,unused))
void exit(int status)
{
sys_exit(status);
}
static __attribute__((unused))
int chdir(const char *path)
{
int ret = sys_chdir(path);
if (ret < 0) {
SET_ERRNO(-ret);
ret = -1;
}
return ret;
}
static __attribute__((unused))
int chmod(const char *path, mode_t mode)
{
int ret = sys_chmod(path, mode);
if (ret < 0) {
SET_ERRNO(-ret);
ret = -1;
}
return ret;
}
static __attribute__((unused))
int chown(const char *path, uid_t owner, gid_t group)
{
int ret = sys_chown(path, owner, group);
if (ret < 0) {
SET_ERRNO(-ret);
ret = -1;
}
return ret;
}
static __attribute__((unused))
int chroot(const char *path)
{
int ret = sys_chroot(path);
if (ret < 0) {
SET_ERRNO(-ret);
ret = -1;
}
return ret;
}
static __attribute__((unused))
int close(int fd)
{
int ret = sys_close(fd);
if (ret < 0) {
SET_ERRNO(-ret);
ret = -1;
}
return ret;
}
static __attribute__((unused))
int dup(int fd)
{
int ret = sys_dup(fd);
if (ret < 0) {
SET_ERRNO(-ret);
ret = -1;
}
return ret;
}
static __attribute__((unused))
int dup2(int old, int new)
{
int ret = sys_dup2(old, new);
if (ret < 0) {
SET_ERRNO(-ret);
ret = -1;
}
return ret;
}
#ifdef __NR_dup3
static __attribute__((unused))
int dup3(int old, int new, int flags)
{
int ret = sys_dup3(old, new, flags);
if (ret < 0) {
SET_ERRNO(-ret);
ret = -1;
}
return ret;
}
#endif
static __attribute__((unused))
int execve(const char *filename, char *const argv[], char *const envp[])
{
int ret = sys_execve(filename, argv, envp);
if (ret < 0) {
SET_ERRNO(-ret);
ret = -1;
}
return ret;
}
static __attribute__((unused))
pid_t fork(void)
{
pid_t ret = sys_fork();
if (ret < 0) {
SET_ERRNO(-ret);
ret = -1;
}
return ret;
}
static __attribute__((unused))
int fsync(int fd)
{
int ret = sys_fsync(fd);
if (ret < 0) {
SET_ERRNO(-ret);
ret = -1;
}
return ret;
}
static __attribute__((unused))
int getdents64(int fd, struct linux_dirent64 *dirp, int count)
{
int ret = sys_getdents64(fd, dirp, count);
if (ret < 0) {
SET_ERRNO(-ret);
ret = -1;
}
return ret;
}
static __attribute__((unused))
pid_t getpgid(pid_t pid)
{
pid_t ret = sys_getpgid(pid);
if (ret < 0) {
SET_ERRNO(-ret);
ret = -1;
}
return ret;
}
static __attribute__((unused))
pid_t getpgrp(void)
{
pid_t ret = sys_getpgrp();
if (ret < 0) {
SET_ERRNO(-ret);
ret = -1;
}
return ret;
}
static __attribute__((unused))
pid_t getpid(void)
{
pid_t ret = sys_getpid();
if (ret < 0) {
SET_ERRNO(-ret);
ret = -1;
}
return ret;
}
static __attribute__((unused))
int gettimeofday(struct timeval *tv, struct timezone *tz)
{
int ret = sys_gettimeofday(tv, tz);
if (ret < 0) {
SET_ERRNO(-ret);
ret = -1;
}
return ret;
}
static __attribute__((unused))
int ioctl(int fd, unsigned long req, void *value)
{
int ret = sys_ioctl(fd, req, value);
if (ret < 0) {
SET_ERRNO(-ret);
ret = -1;
}
return ret;
}
static __attribute__((unused))
int kill(pid_t pid, int signal)
{
int ret = sys_kill(pid, signal);
if (ret < 0) {
SET_ERRNO(-ret);
ret = -1;
}
return ret;
}
static __attribute__((unused))
int link(const char *old, const char *new)
{
int ret = sys_link(old, new);
if (ret < 0) {
SET_ERRNO(-ret);
ret = -1;
}
return ret;
}
static __attribute__((unused))
off_t lseek(int fd, off_t offset, int whence)
{
off_t ret = sys_lseek(fd, offset, whence);
if (ret < 0) {
SET_ERRNO(-ret);
ret = -1;
}
return ret;
}
static __attribute__((unused))
int mkdir(const char *path, mode_t mode)
{
int ret = sys_mkdir(path, mode);
if (ret < 0) {
SET_ERRNO(-ret);
ret = -1;
}
return ret;
}
static __attribute__((unused))
int mknod(const char *path, mode_t mode, dev_t dev)
{
int ret = sys_mknod(path, mode, dev);
if (ret < 0) {
SET_ERRNO(-ret);
ret = -1;
}
return ret;
}
static __attribute__((unused))
int mount(const char *src, const char *tgt,
const char *fst, unsigned long flags,
const void *data)
{
int ret = sys_mount(src, tgt, fst, flags, data);
if (ret < 0) {
SET_ERRNO(-ret);
ret = -1;
}
return ret;
}
static __attribute__((unused))
int open(const char *path, int flags, mode_t mode)
{
int ret = sys_open(path, flags, mode);
if (ret < 0) {
SET_ERRNO(-ret);
ret = -1;
}
return ret;
}
static __attribute__((unused))
int pivot_root(const char *new, const char *old)
{
int ret = sys_pivot_root(new, old);
if (ret < 0) {
SET_ERRNO(-ret);
ret = -1;
}
return ret;
}
static __attribute__((unused))
int poll(struct pollfd *fds, int nfds, int timeout)
{
int ret = sys_poll(fds, nfds, timeout);
if (ret < 0) {
SET_ERRNO(-ret);
ret = -1;
}
return ret;
}
static __attribute__((unused))
ssize_t read(int fd, void *buf, size_t count)
{
ssize_t ret = sys_read(fd, buf, count);
if (ret < 0) {
SET_ERRNO(-ret);
ret = -1;
}
return ret;
}
static __attribute__((unused))
int reboot(int cmd)
{
int ret = sys_reboot(LINUX_REBOOT_MAGIC1, LINUX_REBOOT_MAGIC2, cmd, 0);
if (ret < 0) {
SET_ERRNO(-ret);
ret = -1;
}
return ret;
}
static __attribute__((unused))
void *sbrk(intptr_t inc)
{
void *ret;
/* first call to find current end */
if ((ret = sys_brk(0)) && (sys_brk(ret + inc) == ret + inc))
return ret + inc;
SET_ERRNO(ENOMEM);
return (void *)-1;
}
static __attribute__((unused))
int sched_yield(void)
{
int ret = sys_sched_yield();
if (ret < 0) {
SET_ERRNO(-ret);
ret = -1;
}
return ret;
}
static __attribute__((unused))
int select(int nfds, fd_set *rfds, fd_set *wfds, fd_set *efds, struct timeval *timeout)
{
int ret = sys_select(nfds, rfds, wfds, efds, timeout);
if (ret < 0) {
SET_ERRNO(-ret);
ret = -1;
}
return ret;
}
static __attribute__((unused))
int setpgid(pid_t pid, pid_t pgid)
{
int ret = sys_setpgid(pid, pgid);
if (ret < 0) {
SET_ERRNO(-ret);
ret = -1;
}
return ret;
}
static __attribute__((unused))
pid_t setsid(void)
{
pid_t ret = sys_setsid();
if (ret < 0) {
SET_ERRNO(-ret);
ret = -1;
}
return ret;
}
static __attribute__((unused))
unsigned int sleep(unsigned int seconds)
{
struct timeval my_timeval = { seconds, 0 };
if (sys_select(0, 0, 0, 0, &my_timeval) < 0)
return my_timeval.tv_sec + !!my_timeval.tv_usec;
else
return 0;
}
static __attribute__((unused))
int msleep(unsigned int msecs)
{
struct timeval my_timeval = { msecs / 1000, (msecs % 1000) * 1000 };
if (sys_select(0, 0, 0, 0, &my_timeval) < 0)
return (my_timeval.tv_sec * 1000) +
(my_timeval.tv_usec / 1000) +
!!(my_timeval.tv_usec % 1000);
else
return 0;
}
static __attribute__((unused))
int stat(const char *path, struct stat *buf)
{
int ret = sys_stat(path, buf);
if (ret < 0) {
SET_ERRNO(-ret);
ret = -1;
}
return ret;
}
static __attribute__((unused))
int symlink(const char *old, const char *new)
{
int ret = sys_symlink(old, new);
if (ret < 0) {
SET_ERRNO(-ret);
ret = -1;
}
return ret;
}
static __attribute__((unused))
int tcsetpgrp(int fd, pid_t pid)
{
return ioctl(fd, TIOCSPGRP, &pid);
}
static __attribute__((unused))
mode_t umask(mode_t mode)
{
return sys_umask(mode);
}
static __attribute__((unused))
int umount2(const char *path, int flags)
{
int ret = sys_umount2(path, flags);
if (ret < 0) {
SET_ERRNO(-ret);
ret = -1;
}
return ret;
}
static __attribute__((unused))
int unlink(const char *path)
{
int ret = sys_unlink(path);
if (ret < 0) {
SET_ERRNO(-ret);
ret = -1;
}
return ret;
}
static __attribute__((unused))
pid_t wait4(pid_t pid, int *status, int options, struct rusage *rusage)
{
pid_t ret = sys_wait4(pid, status, options, rusage);
if (ret < 0) {
SET_ERRNO(-ret);
ret = -1;
}
return ret;
}
static __attribute__((unused))
pid_t waitpid(pid_t pid, int *status, int options)
{
pid_t ret = sys_waitpid(pid, status, options);
if (ret < 0) {
SET_ERRNO(-ret);
ret = -1;
}
return ret;
}
static __attribute__((unused))
pid_t wait(int *status)
{
pid_t ret = sys_wait(status);
if (ret < 0) {
SET_ERRNO(-ret);
ret = -1;
}
return ret;
}
static __attribute__((unused))
ssize_t write(int fd, const void *buf, size_t count)
{
ssize_t ret = sys_write(fd, buf, count);
if (ret < 0) {
SET_ERRNO(-ret);
ret = -1;
}
return ret;
}
/* some size-optimized reimplementations of a few common str* and mem*
* functions. They're marked static, except memcpy() and raise() which are used
* by libgcc on ARM, so they are marked weak instead in order not to cause an
* error when building a program made of multiple files (not recommended).
*/
static __attribute__((unused))
void *memmove(void *dst, const void *src, size_t len)
{
ssize_t pos = (dst <= src) ? -1 : (long)len;
void *ret = dst;
while (len--) {
pos += (dst <= src) ? 1 : -1;
((char *)dst)[pos] = ((char *)src)[pos];
}
return ret;
}
static __attribute__((unused))
void *memset(void *dst, int b, size_t len)
{
char *p = dst;
while (len--)
*(p++) = b;
return dst;
}
static __attribute__((unused))
int memcmp(const void *s1, const void *s2, size_t n)
{
size_t ofs = 0;
char c1 = 0;
while (ofs < n && !(c1 = ((char *)s1)[ofs] - ((char *)s2)[ofs])) {
ofs++;
}
return c1;
}
static __attribute__((unused))
char *strcpy(char *dst, const char *src)
{
char *ret = dst;
while ((*dst++ = *src++));
return ret;
}
static __attribute__((unused))
char *strchr(const char *s, int c)
{
while (*s) {
if (*s == (char)c)
return (char *)s;
s++;
}
return NULL;
}
static __attribute__((unused))
char *strrchr(const char *s, int c)
{
const char *ret = NULL;
while (*s) {
if (*s == (char)c)
ret = s;
s++;
}
return (char *)ret;
}
static __attribute__((unused))
size_t nolibc_strlen(const char *str)
{
size_t len;
for (len = 0; str[len]; len++);
return len;
}
#define strlen(str) ({ \
__builtin_constant_p((str)) ? \
__builtin_strlen((str)) : \
nolibc_strlen((str)); \
})
static __attribute__((unused))
int isdigit(int c)
{
return (unsigned int)(c - '0') <= 9;
}
static __attribute__((unused))
long atol(const char *s)
{
unsigned long ret = 0;
unsigned long d;
int neg = 0;
if (*s == '-') {
neg = 1;
s++;
}
while (1) {
d = (*s++) - '0';
if (d > 9)
break;
ret *= 10;
ret += d;
}
return neg ? -ret : ret;
}
static __attribute__((unused))
int atoi(const char *s)
{
return atol(s);
}
static __attribute__((unused))
const char *ltoa(long in)
{
/* large enough for -9223372036854775808 */
static char buffer[21];
char *pos = buffer + sizeof(buffer) - 1;
int neg = in < 0;
unsigned long n = neg ? -in : in;
*pos-- = '\0';
do {
*pos-- = '0' + n % 10;
n /= 10;
if (pos < buffer)
return pos + 1;
} while (n);
if (neg)
*pos-- = '-';
return pos + 1;
}
__attribute__((weak,unused))
void *memcpy(void *dst, const void *src, size_t len)
{
return memmove(dst, src, len);
}
/* needed by libgcc for divide by zero */
__attribute__((weak,unused))
int raise(int signal)
{
return kill(getpid(), signal);
}
/* Here come a few helper functions */
static __attribute__((unused))
void FD_ZERO(fd_set *set)
{
memset(set, 0, sizeof(*set));
}
static __attribute__((unused))
void FD_SET(int fd, fd_set *set)
{
if (fd < 0 || fd >= FD_SETSIZE)
return;
set->fd32[fd / 32] |= 1 << (fd & 31);
}
/* WARNING, it only deals with the 4096 first majors and 256 first minors */
static __attribute__((unused))
dev_t makedev(unsigned int major, unsigned int minor)
{
return ((major & 0xfff) << 8) | (minor & 0xff);
}