1 /* SPDX-License-Identifier: LGPL-2.1 OR MIT */
7 * This file is designed to be used as a libc alternative for minimal programs
8 * with very limited requirements. It consists of a small number of syscall and
9 * type definitions, and the minimal startup code needed to call main().
10 * All syscalls are declared as static functions so that they can be optimized
11 * away by the compiler when not used.
13 * Syscalls are split into 3 levels:
14 * - The lower level is the arch-specific syscall() definition, consisting in
15 * assembly code in compound expressions. These are called my_syscall0() to
16 * my_syscall6() depending on the number of arguments. The MIPS
17 * implementation is limited to 5 arguments. All input arguments are cast
18 * to a long stored in a register. These expressions always return the
19 * syscall's return value as a signed long value which is often either a
20 * pointer or the negated errno value.
22 * - The second level is mostly architecture-independent. It is made of
23 * static functions called sys_<name>() which rely on my_syscallN()
24 * depending on the syscall definition. These functions are responsible
25 * for exposing the appropriate types for the syscall arguments (int,
26 * pointers, etc) and for setting the appropriate return type (often int).
27 * A few of them are architecture-specific because the syscalls are not all
28 * mapped exactly the same among architectures. For example, some archs do
29 * not implement select() and need pselect6() instead, so the sys_select()
30 * function will have to abstract this.
32 * - The third level is the libc call definition. It exposes the lower raw
33 * sys_<name>() calls in a way that looks like what a libc usually does,
34 * takes care of specific input values, and of setting errno upon error.
35 * There can be minor variations compared to standard libc calls. For
36 * example the open() call always takes 3 args here.
38 * The errno variable is declared static and unused. This way it can be
39 * optimized away if not used. However this means that a program made of
40 * multiple C files may observe different errno values (one per C file). For
41 * the type of programs this project targets it usually is not a problem. The
42 * resulting program may even be reduced by defining the NOLIBC_IGNORE_ERRNO
43 * macro, in which case the errno value will never be assigned.
45 * Some stdint-like integer types are defined. These are valid on all currently
46 * supported architectures, because signs are enforced, ints are assumed to be
47 * 32 bits, longs the size of a pointer and long long 64 bits. If more
48 * architectures have to be supported, this may need to be adapted.
50 * Some macro definitions like the O_* values passed to open(), and some
51 * structures like the sys_stat struct depend on the architecture.
53 * The definitions start with the architecture-specific parts, which are picked
54 * based on what the compiler knows about the target architecture, and are
55 * completed with the generic code. Since it is the compiler which sets the
56 * target architecture, cross-compiling normally works out of the box without
57 * having to specify anything.
59 * Finally some very common libc-level functions are provided. It is the case
60 * for a few functions usually found in string.h, ctype.h, or stdlib.h. Nothing
61 * is currently provided regarding stdio emulation.
63 * The macro NOLIBC is always defined, so that it is possible for a program to
64 * check this macro to know if it is being built against and decide to disable
65 * some features or simply not to include some standard libc files.
67 * Ideally this file should be split in multiple files for easier long term
68 * maintenance, but provided as a single file as it is now, it's quite
69 * convenient to use. Maybe some variations involving a set of includes at the
72 * A simple static executable may be built this way :
73 * $ gcc -fno-asynchronous-unwind-tables -fno-ident -s -Os -nostdlib \
74 * -static -include nolibc.h -o hello hello.c -lgcc
76 * A very useful calling convention table may be found here :
77 * http://man7.org/linux/man-pages/man2/syscall.2.html
79 * This doc is quite convenient though not necessarily up to date :
80 * https://w3challs.com/syscalls/
84 #include <asm/unistd.h>
85 #include <asm/ioctls.h>
86 #include <asm/errno.h>
88 #include <linux/loop.h>
89 #include <linux/time.h>
93 /* this way it will be removed if unused */
96 #ifndef NOLIBC_IGNORE_ERRNO
97 #define SET_ERRNO(v) do { errno = (v); } while (0)
99 #define SET_ERRNO(v) do { } while (0)
102 /* errno codes all ensure that they will not conflict with a valid pointer
103 * because they all correspond to the highest addressable memory page.
105 #define MAX_ERRNO 4095
107 /* Declare a few quite common macros and types that usually are in stdlib.h,
108 * stdint.h, ctype.h, unistd.h and a few other common locations.
111 #define NULL ((void *)0)
114 typedef unsigned char uint8_t;
115 typedef signed char int8_t;
116 typedef unsigned short uint16_t;
117 typedef signed short int16_t;
118 typedef unsigned int uint32_t;
119 typedef signed int int32_t;
120 typedef unsigned long long uint64_t;
121 typedef signed long long int64_t;
122 typedef unsigned long size_t;
123 typedef signed long ssize_t;
124 typedef unsigned long uintptr_t;
125 typedef signed long intptr_t;
126 typedef signed long ptrdiff_t;
129 typedef unsigned int dev_t;
130 typedef unsigned long ino_t;
131 typedef unsigned int mode_t;
132 typedef signed int pid_t;
133 typedef unsigned int uid_t;
134 typedef unsigned int gid_t;
135 typedef unsigned long nlink_t;
136 typedef signed long off_t;
137 typedef signed long blksize_t;
138 typedef signed long blkcnt_t;
139 typedef signed long time_t;
148 /* for getdents64() */
149 struct linux_dirent64 {
152 unsigned short d_reclen;
153 unsigned char d_type;
157 /* commonly an fd_set represents 256 FDs */
158 #define FD_SETSIZE 256
159 typedef struct { uint32_t fd32[FD_SETSIZE/32]; } fd_set;
161 /* needed by wait4() */
163 struct timeval ru_utime;
164 struct timeval ru_stime;
181 /* stat flags (WARNING, octal here) */
182 #define S_IFDIR 0040000
183 #define S_IFCHR 0020000
184 #define S_IFBLK 0060000
185 #define S_IFREG 0100000
186 #define S_IFIFO 0010000
187 #define S_IFLNK 0120000
188 #define S_IFSOCK 0140000
189 #define S_IFMT 0170000
191 #define S_ISDIR(mode) (((mode) & S_IFDIR) == S_IFDIR)
192 #define S_ISCHR(mode) (((mode) & S_IFCHR) == S_IFCHR)
193 #define S_ISBLK(mode) (((mode) & S_IFBLK) == S_IFBLK)
194 #define S_ISREG(mode) (((mode) & S_IFREG) == S_IFREG)
195 #define S_ISFIFO(mode) (((mode) & S_IFIFO) == S_IFIFO)
196 #define S_ISLNK(mode) (((mode) & S_IFLNK) == S_IFLNK)
197 #define S_ISSOCK(mode) (((mode) & S_IFSOCK) == S_IFSOCK)
208 /* all the *at functions */
210 #define AT_FDCWD -100
219 #define LINUX_REBOOT_MAGIC1 0xfee1dead
220 #define LINUX_REBOOT_MAGIC2 0x28121969
221 #define LINUX_REBOOT_CMD_HALT 0xcdef0123
222 #define LINUX_REBOOT_CMD_POWER_OFF 0x4321fedc
223 #define LINUX_REBOOT_CMD_RESTART 0x01234567
224 #define LINUX_REBOOT_CMD_SW_SUSPEND 0xd000fce2
227 /* The format of the struct as returned by the libc to the application, which
228 * significantly differs from the format returned by the stat() syscall flavours.
231 dev_t st_dev; /* ID of device containing file */
232 ino_t st_ino; /* inode number */
233 mode_t st_mode; /* protection */
234 nlink_t st_nlink; /* number of hard links */
235 uid_t st_uid; /* user ID of owner */
236 gid_t st_gid; /* group ID of owner */
237 dev_t st_rdev; /* device ID (if special file) */
238 off_t st_size; /* total size, in bytes */
239 blksize_t st_blksize; /* blocksize for file system I/O */
240 blkcnt_t st_blocks; /* number of 512B blocks allocated */
241 time_t st_atime; /* time of last access */
242 time_t st_mtime; /* time of last modification */
243 time_t st_ctime; /* time of last status change */
246 #define WEXITSTATUS(status) (((status) & 0xff00) >> 8)
247 #define WIFEXITED(status) (((status) & 0x7f) == 0)
250 #include <asm/signal.h>
252 /* Below comes the architecture-specific code. For each architecture, we have
253 * the syscall declarations and the _start code definition. This is the only
254 * global part. On all architectures the kernel puts everything in the stack
255 * before jumping to _start just above us, without any return address (_start
256 * is not a function but an entry pint). So at the stack pointer we find argc.
257 * Then argv[] begins, and ends at the first NULL. Then we have envp which
258 * starts and ends with a NULL as well. So envp=argv+argc+1.
261 #if defined(__x86_64__)
262 /* Syscalls for x86_64 :
263 * - registers are 64-bit
264 * - syscall number is passed in rax
265 * - arguments are in rdi, rsi, rdx, r10, r8, r9 respectively
266 * - the system call is performed by calling the syscall instruction
267 * - syscall return comes in rax
268 * - rcx and r8..r11 may be clobbered, others are preserved.
269 * - the arguments are cast to long and assigned into the target registers
270 * which are then simply passed as registers to the asm code, so that we
271 * don't have to experience issues with register constraints.
272 * - the syscall number is always specified last in order to allow to force
273 * some registers before (gcc refuses a %-register at the last position).
276 #define my_syscall0(num) \
279 register long _num asm("rax") = (num); \
285 : "rcx", "r8", "r9", "r10", "r11", "memory", "cc" \
290 #define my_syscall1(num, arg1) \
293 register long _num asm("rax") = (num); \
294 register long _arg1 asm("rdi") = (long)(arg1); \
301 : "rcx", "r8", "r9", "r10", "r11", "memory", "cc" \
306 #define my_syscall2(num, arg1, arg2) \
309 register long _num asm("rax") = (num); \
310 register long _arg1 asm("rdi") = (long)(arg1); \
311 register long _arg2 asm("rsi") = (long)(arg2); \
316 : "r"(_arg1), "r"(_arg2), \
318 : "rcx", "r8", "r9", "r10", "r11", "memory", "cc" \
323 #define my_syscall3(num, arg1, arg2, arg3) \
326 register long _num asm("rax") = (num); \
327 register long _arg1 asm("rdi") = (long)(arg1); \
328 register long _arg2 asm("rsi") = (long)(arg2); \
329 register long _arg3 asm("rdx") = (long)(arg3); \
334 : "r"(_arg1), "r"(_arg2), "r"(_arg3), \
336 : "rcx", "r8", "r9", "r10", "r11", "memory", "cc" \
341 #define my_syscall4(num, arg1, arg2, arg3, arg4) \
344 register long _num asm("rax") = (num); \
345 register long _arg1 asm("rdi") = (long)(arg1); \
346 register long _arg2 asm("rsi") = (long)(arg2); \
347 register long _arg3 asm("rdx") = (long)(arg3); \
348 register long _arg4 asm("r10") = (long)(arg4); \
352 : "=a" (_ret), "=r"(_arg4) \
353 : "r"(_arg1), "r"(_arg2), "r"(_arg3), "r"(_arg4), \
355 : "rcx", "r8", "r9", "r11", "memory", "cc" \
360 #define my_syscall5(num, arg1, arg2, arg3, arg4, arg5) \
363 register long _num asm("rax") = (num); \
364 register long _arg1 asm("rdi") = (long)(arg1); \
365 register long _arg2 asm("rsi") = (long)(arg2); \
366 register long _arg3 asm("rdx") = (long)(arg3); \
367 register long _arg4 asm("r10") = (long)(arg4); \
368 register long _arg5 asm("r8") = (long)(arg5); \
372 : "=a" (_ret), "=r"(_arg4), "=r"(_arg5) \
373 : "r"(_arg1), "r"(_arg2), "r"(_arg3), "r"(_arg4), "r"(_arg5), \
375 : "rcx", "r9", "r11", "memory", "cc" \
380 #define my_syscall6(num, arg1, arg2, arg3, arg4, arg5, arg6) \
383 register long _num asm("rax") = (num); \
384 register long _arg1 asm("rdi") = (long)(arg1); \
385 register long _arg2 asm("rsi") = (long)(arg2); \
386 register long _arg3 asm("rdx") = (long)(arg3); \
387 register long _arg4 asm("r10") = (long)(arg4); \
388 register long _arg5 asm("r8") = (long)(arg5); \
389 register long _arg6 asm("r9") = (long)(arg6); \
393 : "=a" (_ret), "=r"(_arg4), "=r"(_arg5) \
394 : "r"(_arg1), "r"(_arg2), "r"(_arg3), "r"(_arg4), "r"(_arg5), \
395 "r"(_arg6), "0"(_num) \
396 : "rcx", "r11", "memory", "cc" \
402 asm(".section .text\n"
405 "pop %rdi\n" // argc (first arg, %rdi)
406 "mov %rsp, %rsi\n" // argv[] (second arg, %rsi)
407 "lea 8(%rsi,%rdi,8),%rdx\n" // then a NULL then envp (third arg, %rdx)
408 "and $-16, %rsp\n" // x86 ABI : esp must be 16-byte aligned when
409 "sub $8, %rsp\n" // entering the callee
410 "call main\n" // main() returns the status code, we'll exit with it.
411 "movzb %al, %rdi\n" // retrieve exit code from 8 lower bits
412 "mov $60, %rax\n" // NR_exit == 60
413 "syscall\n" // really exit
414 "hlt\n" // ensure it does not return
423 #define O_NOCTTY 0x100
424 #define O_TRUNC 0x200
425 #define O_APPEND 0x400
426 #define O_NONBLOCK 0x800
427 #define O_DIRECTORY 0x10000
429 /* The struct returned by the stat() syscall, equivalent to stat64(). The
430 * syscall returns 116 bytes and stops in the middle of __unused.
432 struct sys_stat_struct {
433 unsigned long st_dev;
434 unsigned long st_ino;
435 unsigned long st_nlink;
436 unsigned int st_mode;
441 unsigned long st_rdev;
446 unsigned long st_atime;
447 unsigned long st_atime_nsec;
448 unsigned long st_mtime;
450 unsigned long st_mtime_nsec;
451 unsigned long st_ctime;
452 unsigned long st_ctime_nsec;
456 #elif defined(__i386__) || defined(__i486__) || defined(__i586__) || defined(__i686__)
457 /* Syscalls for i386 :
458 * - mostly similar to x86_64
459 * - registers are 32-bit
460 * - syscall number is passed in eax
461 * - arguments are in ebx, ecx, edx, esi, edi, ebp respectively
462 * - all registers are preserved (except eax of course)
463 * - the system call is performed by calling int $0x80
464 * - syscall return comes in eax
465 * - the arguments are cast to long and assigned into the target registers
466 * which are then simply passed as registers to the asm code, so that we
467 * don't have to experience issues with register constraints.
468 * - the syscall number is always specified last in order to allow to force
469 * some registers before (gcc refuses a %-register at the last position).
471 * Also, i386 supports the old_select syscall if newselect is not available
473 #define __ARCH_WANT_SYS_OLD_SELECT
475 #define my_syscall0(num) \
478 register long _num asm("eax") = (num); \
489 #define my_syscall1(num, arg1) \
492 register long _num asm("eax") = (num); \
493 register long _arg1 asm("ebx") = (long)(arg1); \
505 #define my_syscall2(num, arg1, arg2) \
508 register long _num asm("eax") = (num); \
509 register long _arg1 asm("ebx") = (long)(arg1); \
510 register long _arg2 asm("ecx") = (long)(arg2); \
515 : "r"(_arg1), "r"(_arg2), \
522 #define my_syscall3(num, arg1, arg2, arg3) \
525 register long _num asm("eax") = (num); \
526 register long _arg1 asm("ebx") = (long)(arg1); \
527 register long _arg2 asm("ecx") = (long)(arg2); \
528 register long _arg3 asm("edx") = (long)(arg3); \
533 : "r"(_arg1), "r"(_arg2), "r"(_arg3), \
540 #define my_syscall4(num, arg1, arg2, arg3, arg4) \
543 register long _num asm("eax") = (num); \
544 register long _arg1 asm("ebx") = (long)(arg1); \
545 register long _arg2 asm("ecx") = (long)(arg2); \
546 register long _arg3 asm("edx") = (long)(arg3); \
547 register long _arg4 asm("esi") = (long)(arg4); \
552 : "r"(_arg1), "r"(_arg2), "r"(_arg3), "r"(_arg4), \
559 #define my_syscall5(num, arg1, arg2, arg3, arg4, arg5) \
562 register long _num asm("eax") = (num); \
563 register long _arg1 asm("ebx") = (long)(arg1); \
564 register long _arg2 asm("ecx") = (long)(arg2); \
565 register long _arg3 asm("edx") = (long)(arg3); \
566 register long _arg4 asm("esi") = (long)(arg4); \
567 register long _arg5 asm("edi") = (long)(arg5); \
572 : "r"(_arg1), "r"(_arg2), "r"(_arg3), "r"(_arg4), "r"(_arg5), \
580 asm(".section .text\n"
583 "pop %eax\n" // argc (first arg, %eax)
584 "mov %esp, %ebx\n" // argv[] (second arg, %ebx)
585 "lea 4(%ebx,%eax,4),%ecx\n" // then a NULL then envp (third arg, %ecx)
586 "and $-16, %esp\n" // x86 ABI : esp must be 16-byte aligned when
587 "push %ecx\n" // push all registers on the stack so that we
588 "push %ebx\n" // support both regparm and plain stack modes
590 "call main\n" // main() returns the status code in %eax
591 "movzbl %al, %ebx\n" // retrieve exit code from lower 8 bits
592 "movl $1, %eax\n" // NR_exit == 1
593 "int $0x80\n" // exit now
594 "hlt\n" // ensure it does not
603 #define O_NOCTTY 0x100
604 #define O_TRUNC 0x200
605 #define O_APPEND 0x400
606 #define O_NONBLOCK 0x800
607 #define O_DIRECTORY 0x10000
609 /* The struct returned by the stat() syscall, 32-bit only, the syscall returns
610 * exactly 56 bytes (stops before the unused array).
612 struct sys_stat_struct {
613 unsigned long st_dev;
614 unsigned long st_ino;
615 unsigned short st_mode;
616 unsigned short st_nlink;
617 unsigned short st_uid;
618 unsigned short st_gid;
620 unsigned long st_rdev;
621 unsigned long st_size;
622 unsigned long st_blksize;
623 unsigned long st_blocks;
625 unsigned long st_atime;
626 unsigned long st_atime_nsec;
627 unsigned long st_mtime;
628 unsigned long st_mtime_nsec;
630 unsigned long st_ctime;
631 unsigned long st_ctime_nsec;
632 unsigned long __unused[2];
635 #elif defined(__ARM_EABI__)
636 /* Syscalls for ARM in ARM or Thumb modes :
637 * - registers are 32-bit
638 * - stack is 8-byte aligned
639 * ( http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.faqs/ka4127.html)
640 * - syscall number is passed in r7
641 * - arguments are in r0, r1, r2, r3, r4, r5
642 * - the system call is performed by calling svc #0
643 * - syscall return comes in r0.
644 * - only lr is clobbered.
645 * - the arguments are cast to long and assigned into the target registers
646 * which are then simply passed as registers to the asm code, so that we
647 * don't have to experience issues with register constraints.
648 * - the syscall number is always specified last in order to allow to force
649 * some registers before (gcc refuses a %-register at the last position).
651 * Also, ARM supports the old_select syscall if newselect is not available
653 #define __ARCH_WANT_SYS_OLD_SELECT
655 #define my_syscall0(num) \
657 register long _num asm("r7") = (num); \
658 register long _arg1 asm("r0"); \
664 : "memory", "cc", "lr" \
669 #define my_syscall1(num, arg1) \
671 register long _num asm("r7") = (num); \
672 register long _arg1 asm("r0") = (long)(arg1); \
679 : "memory", "cc", "lr" \
684 #define my_syscall2(num, arg1, arg2) \
686 register long _num asm("r7") = (num); \
687 register long _arg1 asm("r0") = (long)(arg1); \
688 register long _arg2 asm("r1") = (long)(arg2); \
693 : "r"(_arg1), "r"(_arg2), \
695 : "memory", "cc", "lr" \
700 #define my_syscall3(num, arg1, arg2, arg3) \
702 register long _num asm("r7") = (num); \
703 register long _arg1 asm("r0") = (long)(arg1); \
704 register long _arg2 asm("r1") = (long)(arg2); \
705 register long _arg3 asm("r2") = (long)(arg3); \
710 : "r"(_arg1), "r"(_arg2), "r"(_arg3), \
712 : "memory", "cc", "lr" \
717 #define my_syscall4(num, arg1, arg2, arg3, arg4) \
719 register long _num asm("r7") = (num); \
720 register long _arg1 asm("r0") = (long)(arg1); \
721 register long _arg2 asm("r1") = (long)(arg2); \
722 register long _arg3 asm("r2") = (long)(arg3); \
723 register long _arg4 asm("r3") = (long)(arg4); \
728 : "r"(_arg1), "r"(_arg2), "r"(_arg3), "r"(_arg4), \
730 : "memory", "cc", "lr" \
735 #define my_syscall5(num, arg1, arg2, arg3, arg4, arg5) \
737 register long _num asm("r7") = (num); \
738 register long _arg1 asm("r0") = (long)(arg1); \
739 register long _arg2 asm("r1") = (long)(arg2); \
740 register long _arg3 asm("r2") = (long)(arg3); \
741 register long _arg4 asm("r3") = (long)(arg4); \
742 register long _arg5 asm("r4") = (long)(arg5); \
747 : "r"(_arg1), "r"(_arg2), "r"(_arg3), "r"(_arg4), "r"(_arg5), \
749 : "memory", "cc", "lr" \
755 asm(".section .text\n"
758 #if defined(__THUMBEB__) || defined(__THUMBEL__)
759 /* We enter here in 32-bit mode but if some previous functions were in
760 * 16-bit mode, the assembler cannot know, so we need to tell it we're in
761 * 32-bit now, then switch to 16-bit (is there a better way to do it than
762 * adding 1 by hand ?) and tell the asm we're now in 16-bit mode so that
763 * it generates correct instructions. Note that we do not support thumb1.
770 "pop {%r0}\n" // argc was in the stack
771 "mov %r1, %sp\n" // argv = sp
772 "add %r2, %r1, %r0, lsl #2\n" // envp = argv + 4*argc ...
773 "add %r2, %r2, $4\n" // ... + 4
774 "and %r3, %r1, $-8\n" // AAPCS : sp must be 8-byte aligned in the
775 "mov %sp, %r3\n" // callee, an bl doesn't push (lr=pc)
776 "bl main\n" // main() returns the status code, we'll exit with it.
777 "and %r0, %r0, $0xff\n" // limit exit code to 8 bits
778 "movs r7, $1\n" // NR_exit == 1
788 #define O_NOCTTY 0x100
789 #define O_TRUNC 0x200
790 #define O_APPEND 0x400
791 #define O_NONBLOCK 0x800
792 #define O_DIRECTORY 0x4000
794 /* The struct returned by the stat() syscall, 32-bit only, the syscall returns
795 * exactly 56 bytes (stops before the unused array). In big endian, the format
796 * differs as devices are returned as short only.
798 struct sys_stat_struct {
799 #if defined(__ARMEB__)
800 unsigned short st_dev;
801 unsigned short __pad1;
803 unsigned long st_dev;
805 unsigned long st_ino;
806 unsigned short st_mode;
807 unsigned short st_nlink;
808 unsigned short st_uid;
809 unsigned short st_gid;
810 #if defined(__ARMEB__)
811 unsigned short st_rdev;
812 unsigned short __pad2;
814 unsigned long st_rdev;
816 unsigned long st_size;
817 unsigned long st_blksize;
818 unsigned long st_blocks;
819 unsigned long st_atime;
820 unsigned long st_atime_nsec;
821 unsigned long st_mtime;
822 unsigned long st_mtime_nsec;
823 unsigned long st_ctime;
824 unsigned long st_ctime_nsec;
825 unsigned long __unused[2];
828 #elif defined(__aarch64__)
829 /* Syscalls for AARCH64 :
830 * - registers are 64-bit
831 * - stack is 16-byte aligned
832 * - syscall number is passed in x8
833 * - arguments are in x0, x1, x2, x3, x4, x5
834 * - the system call is performed by calling svc 0
835 * - syscall return comes in x0.
836 * - the arguments are cast to long and assigned into the target registers
837 * which are then simply passed as registers to the asm code, so that we
838 * don't have to experience issues with register constraints.
840 * On aarch64, select() is not implemented so we have to use pselect6().
842 #define __ARCH_WANT_SYS_PSELECT6
844 #define my_syscall0(num) \
846 register long _num asm("x8") = (num); \
847 register long _arg1 asm("x0"); \
858 #define my_syscall1(num, arg1) \
860 register long _num asm("x8") = (num); \
861 register long _arg1 asm("x0") = (long)(arg1); \
873 #define my_syscall2(num, arg1, arg2) \
875 register long _num asm("x8") = (num); \
876 register long _arg1 asm("x0") = (long)(arg1); \
877 register long _arg2 asm("x1") = (long)(arg2); \
882 : "r"(_arg1), "r"(_arg2), \
889 #define my_syscall3(num, arg1, arg2, arg3) \
891 register long _num asm("x8") = (num); \
892 register long _arg1 asm("x0") = (long)(arg1); \
893 register long _arg2 asm("x1") = (long)(arg2); \
894 register long _arg3 asm("x2") = (long)(arg3); \
899 : "r"(_arg1), "r"(_arg2), "r"(_arg3), \
906 #define my_syscall4(num, arg1, arg2, arg3, arg4) \
908 register long _num asm("x8") = (num); \
909 register long _arg1 asm("x0") = (long)(arg1); \
910 register long _arg2 asm("x1") = (long)(arg2); \
911 register long _arg3 asm("x2") = (long)(arg3); \
912 register long _arg4 asm("x3") = (long)(arg4); \
917 : "r"(_arg1), "r"(_arg2), "r"(_arg3), "r"(_arg4), \
924 #define my_syscall5(num, arg1, arg2, arg3, arg4, arg5) \
926 register long _num asm("x8") = (num); \
927 register long _arg1 asm("x0") = (long)(arg1); \
928 register long _arg2 asm("x1") = (long)(arg2); \
929 register long _arg3 asm("x2") = (long)(arg3); \
930 register long _arg4 asm("x3") = (long)(arg4); \
931 register long _arg5 asm("x4") = (long)(arg5); \
936 : "r"(_arg1), "r"(_arg2), "r"(_arg3), "r"(_arg4), "r"(_arg5), \
943 #define my_syscall6(num, arg1, arg2, arg3, arg4, arg5, arg6) \
945 register long _num asm("x8") = (num); \
946 register long _arg1 asm("x0") = (long)(arg1); \
947 register long _arg2 asm("x1") = (long)(arg2); \
948 register long _arg3 asm("x2") = (long)(arg3); \
949 register long _arg4 asm("x3") = (long)(arg4); \
950 register long _arg5 asm("x4") = (long)(arg5); \
951 register long _arg6 asm("x5") = (long)(arg6); \
956 : "r"(_arg1), "r"(_arg2), "r"(_arg3), "r"(_arg4), "r"(_arg5), \
957 "r"(_arg6), "r"(_num) \
964 asm(".section .text\n"
967 "ldr x0, [sp]\n" // argc (x0) was in the stack
968 "add x1, sp, 8\n" // argv (x1) = sp
969 "lsl x2, x0, 3\n" // envp (x2) = 8*argc ...
970 "add x2, x2, 8\n" // + 8 (skip null)
971 "add x2, x2, x1\n" // + argv
972 "and sp, x1, -16\n" // sp must be 16-byte aligned in the callee
973 "bl main\n" // main() returns the status code, we'll exit with it.
974 "and x0, x0, 0xff\n" // limit exit code to 8 bits
975 "mov x8, 93\n" // NR_exit == 93
985 #define O_NOCTTY 0x100
986 #define O_TRUNC 0x200
987 #define O_APPEND 0x400
988 #define O_NONBLOCK 0x800
989 #define O_DIRECTORY 0x4000
991 /* The struct returned by the newfstatat() syscall. Differs slightly from the
992 * x86_64's stat one by field ordering, so be careful.
994 struct sys_stat_struct {
995 unsigned long st_dev;
996 unsigned long st_ino;
997 unsigned int st_mode;
998 unsigned int st_nlink;
1000 unsigned int st_gid;
1002 unsigned long st_rdev;
1003 unsigned long __pad1;
1010 unsigned long st_atime_nsec;
1013 unsigned long st_mtime_nsec;
1015 unsigned long st_ctime_nsec;
1016 unsigned int __unused[2];
1019 #elif defined(__mips__) && defined(_ABIO32)
1020 /* Syscalls for MIPS ABI O32 :
1021 * - WARNING! there's always a delayed slot!
1022 * - WARNING again, the syntax is different, registers take a '$' and numbers
1024 * - registers are 32-bit
1025 * - stack is 8-byte aligned
1026 * - syscall number is passed in v0 (starts at 0xfa0).
1027 * - arguments are in a0, a1, a2, a3, then the stack. The caller needs to
1028 * leave some room in the stack for the callee to save a0..a3 if needed.
1029 * - Many registers are clobbered, in fact only a0..a2 and s0..s8 are
1030 * preserved. See: https://www.linux-mips.org/wiki/Syscall as well as
1031 * scall32-o32.S in the kernel sources.
1032 * - the system call is performed by calling "syscall"
1033 * - syscall return comes in v0, and register a3 needs to be checked to know
1034 * if an error occurred, in which case errno is in v0.
1035 * - the arguments are cast to long and assigned into the target registers
1036 * which are then simply passed as registers to the asm code, so that we
1037 * don't have to experience issues with register constraints.
1040 #define my_syscall0(num) \
1042 register long _num asm("v0") = (num); \
1043 register long _arg4 asm("a3"); \
1046 "addiu $sp, $sp, -32\n" \
1048 "addiu $sp, $sp, 32\n" \
1049 : "=r"(_num), "=r"(_arg4) \
1051 : "memory", "cc", "at", "v1", "hi", "lo", \
1052 "t0", "t1", "t2", "t3", "t4", "t5", "t6", "t7", "t8", "t9" \
1054 _arg4 ? -_num : _num; \
1057 #define my_syscall1(num, arg1) \
1059 register long _num asm("v0") = (num); \
1060 register long _arg1 asm("a0") = (long)(arg1); \
1061 register long _arg4 asm("a3"); \
1064 "addiu $sp, $sp, -32\n" \
1066 "addiu $sp, $sp, 32\n" \
1067 : "=r"(_num), "=r"(_arg4) \
1070 : "memory", "cc", "at", "v1", "hi", "lo", \
1071 "t0", "t1", "t2", "t3", "t4", "t5", "t6", "t7", "t8", "t9" \
1073 _arg4 ? -_num : _num; \
1076 #define my_syscall2(num, arg1, arg2) \
1078 register long _num asm("v0") = (num); \
1079 register long _arg1 asm("a0") = (long)(arg1); \
1080 register long _arg2 asm("a1") = (long)(arg2); \
1081 register long _arg4 asm("a3"); \
1084 "addiu $sp, $sp, -32\n" \
1086 "addiu $sp, $sp, 32\n" \
1087 : "=r"(_num), "=r"(_arg4) \
1089 "r"(_arg1), "r"(_arg2) \
1090 : "memory", "cc", "at", "v1", "hi", "lo", \
1091 "t0", "t1", "t2", "t3", "t4", "t5", "t6", "t7", "t8", "t9" \
1093 _arg4 ? -_num : _num; \
1096 #define my_syscall3(num, arg1, arg2, arg3) \
1098 register long _num asm("v0") = (num); \
1099 register long _arg1 asm("a0") = (long)(arg1); \
1100 register long _arg2 asm("a1") = (long)(arg2); \
1101 register long _arg3 asm("a2") = (long)(arg3); \
1102 register long _arg4 asm("a3"); \
1105 "addiu $sp, $sp, -32\n" \
1107 "addiu $sp, $sp, 32\n" \
1108 : "=r"(_num), "=r"(_arg4) \
1110 "r"(_arg1), "r"(_arg2), "r"(_arg3) \
1111 : "memory", "cc", "at", "v1", "hi", "lo", \
1112 "t0", "t1", "t2", "t3", "t4", "t5", "t6", "t7", "t8", "t9" \
1114 _arg4 ? -_num : _num; \
1117 #define my_syscall4(num, arg1, arg2, arg3, arg4) \
1119 register long _num asm("v0") = (num); \
1120 register long _arg1 asm("a0") = (long)(arg1); \
1121 register long _arg2 asm("a1") = (long)(arg2); \
1122 register long _arg3 asm("a2") = (long)(arg3); \
1123 register long _arg4 asm("a3") = (long)(arg4); \
1126 "addiu $sp, $sp, -32\n" \
1128 "addiu $sp, $sp, 32\n" \
1129 : "=r" (_num), "=r"(_arg4) \
1131 "r"(_arg1), "r"(_arg2), "r"(_arg3), "r"(_arg4) \
1132 : "memory", "cc", "at", "v1", "hi", "lo", \
1133 "t0", "t1", "t2", "t3", "t4", "t5", "t6", "t7", "t8", "t9" \
1135 _arg4 ? -_num : _num; \
1138 #define my_syscall5(num, arg1, arg2, arg3, arg4, arg5) \
1140 register long _num asm("v0") = (num); \
1141 register long _arg1 asm("a0") = (long)(arg1); \
1142 register long _arg2 asm("a1") = (long)(arg2); \
1143 register long _arg3 asm("a2") = (long)(arg3); \
1144 register long _arg4 asm("a3") = (long)(arg4); \
1145 register long _arg5 = (long)(arg5); \
1148 "addiu $sp, $sp, -32\n" \
1149 "sw %7, 16($sp)\n" \
1151 "addiu $sp, $sp, 32\n" \
1152 : "=r" (_num), "=r"(_arg4) \
1154 "r"(_arg1), "r"(_arg2), "r"(_arg3), "r"(_arg4), "r"(_arg5) \
1155 : "memory", "cc", "at", "v1", "hi", "lo", \
1156 "t0", "t1", "t2", "t3", "t4", "t5", "t6", "t7", "t8", "t9" \
1158 _arg4 ? -_num : _num; \
1161 /* startup code, note that it's called __start on MIPS */
1162 asm(".section .text\n"
1169 "lw $a0,($sp)\n" // argc was in the stack
1170 "addiu $a1, $sp, 4\n" // argv = sp + 4
1171 "sll $a2, $a0, 2\n" // a2 = argc * 4
1172 "add $a2, $a2, $a1\n" // envp = argv + 4*argc ...
1173 "addiu $a2, $a2, 4\n" // ... + 4
1175 "and $sp, $sp, $t0\n" // sp must be 8-byte aligned
1176 "addiu $sp,$sp,-16\n" // the callee expects to save a0..a3 there!
1177 "jal main\n" // main() returns the status code, we'll exit with it.
1178 "nop\n" // delayed slot
1179 "and $a0, $v0, 0xff\n" // limit exit code to 8 bits
1180 "li $v0, 4001\n" // NR_exit == 4001
1189 #define O_APPEND 0x0008
1190 #define O_NONBLOCK 0x0080
1191 #define O_CREAT 0x0100
1192 #define O_TRUNC 0x0200
1193 #define O_EXCL 0x0400
1194 #define O_NOCTTY 0x0800
1195 #define O_DIRECTORY 0x10000
1197 /* The struct returned by the stat() syscall. 88 bytes are returned by the
1200 struct sys_stat_struct {
1201 unsigned int st_dev;
1203 unsigned long st_ino;
1204 unsigned int st_mode;
1205 unsigned int st_nlink;
1206 unsigned int st_uid;
1207 unsigned int st_gid;
1208 unsigned int st_rdev;
1223 #elif defined(__riscv)
1225 #if __riscv_xlen == 64
1228 #elif __riscv_xlen == 32
1233 /* Syscalls for RISCV :
1234 * - stack is 16-byte aligned
1235 * - syscall number is passed in a7
1236 * - arguments are in a0, a1, a2, a3, a4, a5
1237 * - the system call is performed by calling ecall
1238 * - syscall return comes in a0
1239 * - the arguments are cast to long and assigned into the target
1240 * registers which are then simply passed as registers to the asm code,
1241 * so that we don't have to experience issues with register constraints.
1244 #define my_syscall0(num) \
1246 register long _num asm("a7") = (num); \
1247 register long _arg1 asm("a0"); \
1258 #define my_syscall1(num, arg1) \
1260 register long _num asm("a7") = (num); \
1261 register long _arg1 asm("a0") = (long)(arg1); \
1272 #define my_syscall2(num, arg1, arg2) \
1274 register long _num asm("a7") = (num); \
1275 register long _arg1 asm("a0") = (long)(arg1); \
1276 register long _arg2 asm("a1") = (long)(arg2); \
1288 #define my_syscall3(num, arg1, arg2, arg3) \
1290 register long _num asm("a7") = (num); \
1291 register long _arg1 asm("a0") = (long)(arg1); \
1292 register long _arg2 asm("a1") = (long)(arg2); \
1293 register long _arg3 asm("a2") = (long)(arg3); \
1298 : "r"(_arg2), "r"(_arg3), \
1305 #define my_syscall4(num, arg1, arg2, arg3, arg4) \
1307 register long _num asm("a7") = (num); \
1308 register long _arg1 asm("a0") = (long)(arg1); \
1309 register long _arg2 asm("a1") = (long)(arg2); \
1310 register long _arg3 asm("a2") = (long)(arg3); \
1311 register long _arg4 asm("a3") = (long)(arg4); \
1316 : "r"(_arg2), "r"(_arg3), "r"(_arg4), \
1323 #define my_syscall5(num, arg1, arg2, arg3, arg4, arg5) \
1325 register long _num asm("a7") = (num); \
1326 register long _arg1 asm("a0") = (long)(arg1); \
1327 register long _arg2 asm("a1") = (long)(arg2); \
1328 register long _arg3 asm("a2") = (long)(arg3); \
1329 register long _arg4 asm("a3") = (long)(arg4); \
1330 register long _arg5 asm("a4") = (long)(arg5); \
1335 : "r"(_arg2), "r"(_arg3), "r"(_arg4), "r"(_arg5), \
1342 #define my_syscall6(num, arg1, arg2, arg3, arg4, arg5, arg6) \
1344 register long _num asm("a7") = (num); \
1345 register long _arg1 asm("a0") = (long)(arg1); \
1346 register long _arg2 asm("a1") = (long)(arg2); \
1347 register long _arg3 asm("a2") = (long)(arg3); \
1348 register long _arg4 asm("a3") = (long)(arg4); \
1349 register long _arg5 asm("a4") = (long)(arg5); \
1350 register long _arg6 asm("a5") = (long)(arg6); \
1355 : "r"(_arg2), "r"(_arg3), "r"(_arg4), "r"(_arg5), "r"(_arg6), \
1363 asm(".section .text\n"
1368 "lla gp, __global_pointer$\n"
1370 "ld a0, 0(sp)\n" // argc (a0) was in the stack
1371 "add a1, sp, "SZREG"\n" // argv (a1) = sp
1372 "slli a2, a0, "PTRLOG"\n" // envp (a2) = SZREG*argc ...
1373 "add a2, a2, "SZREG"\n" // + SZREG (skip null)
1374 "add a2,a2,a1\n" // + argv
1375 "andi sp,a1,-16\n" // sp must be 16-byte aligned
1376 "call main\n" // main() returns the status code, we'll exit with it.
1377 "andi a0, a0, 0xff\n" // limit exit code to 8 bits
1378 "li a7, 93\n" // NR_exit == 93
1386 #define O_CREAT 0x100
1387 #define O_EXCL 0x200
1388 #define O_NOCTTY 0x400
1389 #define O_TRUNC 0x1000
1390 #define O_APPEND 0x2000
1391 #define O_NONBLOCK 0x4000
1392 #define O_DIRECTORY 0x200000
1394 struct sys_stat_struct {
1395 unsigned long st_dev; /* Device. */
1396 unsigned long st_ino; /* File serial number. */
1397 unsigned int st_mode; /* File mode. */
1398 unsigned int st_nlink; /* Link count. */
1399 unsigned int st_uid; /* User ID of the file's owner. */
1400 unsigned int st_gid; /* Group ID of the file's group. */
1401 unsigned long st_rdev; /* Device number, if device. */
1402 unsigned long __pad1;
1403 long st_size; /* Size of file, in bytes. */
1404 int st_blksize; /* Optimal block size for I/O. */
1406 long st_blocks; /* Number 512-byte blocks allocated. */
1407 long st_atime; /* Time of last access. */
1408 unsigned long st_atime_nsec;
1409 long st_mtime; /* Time of last modification. */
1410 unsigned long st_mtime_nsec;
1411 long st_ctime; /* Time of last status change. */
1412 unsigned long st_ctime_nsec;
1413 unsigned int __unused4;
1414 unsigned int __unused5;
1420 /* Below are the C functions used to declare the raw syscalls. They try to be
1421 * architecture-agnostic, and return either a success or -errno. Declaring them
1422 * static will lead to them being inlined in most cases, but it's still possible
1423 * to reference them by a pointer if needed.
1425 static __attribute__((unused))
1426 void *sys_brk(void *addr)
1428 return (void *)my_syscall1(__NR_brk, addr);
1431 static __attribute__((noreturn,unused))
1432 void sys_exit(int status)
1434 my_syscall1(__NR_exit, status & 255);
1435 while(1); // shut the "noreturn" warnings.
1438 static __attribute__((unused))
1439 int sys_chdir(const char *path)
1441 return my_syscall1(__NR_chdir, path);
1444 static __attribute__((unused))
1445 int sys_chmod(const char *path, mode_t mode)
1447 #ifdef __NR_fchmodat
1448 return my_syscall4(__NR_fchmodat, AT_FDCWD, path, mode, 0);
1449 #elif defined(__NR_chmod)
1450 return my_syscall2(__NR_chmod, path, mode);
1452 #error Neither __NR_fchmodat nor __NR_chmod defined, cannot implement sys_chmod()
1456 static __attribute__((unused))
1457 int sys_chown(const char *path, uid_t owner, gid_t group)
1459 #ifdef __NR_fchownat
1460 return my_syscall5(__NR_fchownat, AT_FDCWD, path, owner, group, 0);
1461 #elif defined(__NR_chown)
1462 return my_syscall3(__NR_chown, path, owner, group);
1464 #error Neither __NR_fchownat nor __NR_chown defined, cannot implement sys_chown()
1468 static __attribute__((unused))
1469 int sys_chroot(const char *path)
1471 return my_syscall1(__NR_chroot, path);
1474 static __attribute__((unused))
1475 int sys_close(int fd)
1477 return my_syscall1(__NR_close, fd);
1480 static __attribute__((unused))
1483 return my_syscall1(__NR_dup, fd);
1487 static __attribute__((unused))
1488 int sys_dup3(int old, int new, int flags)
1490 return my_syscall3(__NR_dup3, old, new, flags);
1494 static __attribute__((unused))
1495 int sys_dup2(int old, int new)
1498 return my_syscall3(__NR_dup3, old, new, 0);
1499 #elif defined(__NR_dup2)
1500 return my_syscall2(__NR_dup2, old, new);
1502 #error Neither __NR_dup3 nor __NR_dup2 defined, cannot implement sys_dup2()
1506 static __attribute__((unused))
1507 int sys_execve(const char *filename, char *const argv[], char *const envp[])
1509 return my_syscall3(__NR_execve, filename, argv, envp);
1512 static __attribute__((unused))
1513 pid_t sys_fork(void)
1516 /* note: some archs only have clone() and not fork(). Different archs
1517 * have a different API, but most archs have the flags on first arg and
1518 * will not use the rest with no other flag.
1520 return my_syscall5(__NR_clone, SIGCHLD, 0, 0, 0, 0);
1521 #elif defined(__NR_fork)
1522 return my_syscall0(__NR_fork);
1524 #error Neither __NR_clone nor __NR_fork defined, cannot implement sys_fork()
1528 static __attribute__((unused))
1529 int sys_fsync(int fd)
1531 return my_syscall1(__NR_fsync, fd);
1534 static __attribute__((unused))
1535 int sys_getdents64(int fd, struct linux_dirent64 *dirp, int count)
1537 return my_syscall3(__NR_getdents64, fd, dirp, count);
1540 static __attribute__((unused))
1541 pid_t sys_getpgid(pid_t pid)
1543 return my_syscall1(__NR_getpgid, pid);
1546 static __attribute__((unused))
1547 pid_t sys_getpgrp(void)
1549 return sys_getpgid(0);
1552 static __attribute__((unused))
1553 pid_t sys_getpid(void)
1555 return my_syscall0(__NR_getpid);
1558 static __attribute__((unused))
1559 int sys_gettimeofday(struct timeval *tv, struct timezone *tz)
1561 return my_syscall2(__NR_gettimeofday, tv, tz);
1564 static __attribute__((unused))
1565 int sys_ioctl(int fd, unsigned long req, void *value)
1567 return my_syscall3(__NR_ioctl, fd, req, value);
1570 static __attribute__((unused))
1571 int sys_kill(pid_t pid, int signal)
1573 return my_syscall2(__NR_kill, pid, signal);
1576 static __attribute__((unused))
1577 int sys_link(const char *old, const char *new)
1580 return my_syscall5(__NR_linkat, AT_FDCWD, old, AT_FDCWD, new, 0);
1581 #elif defined(__NR_link)
1582 return my_syscall2(__NR_link, old, new);
1584 #error Neither __NR_linkat nor __NR_link defined, cannot implement sys_link()
1588 static __attribute__((unused))
1589 off_t sys_lseek(int fd, off_t offset, int whence)
1591 return my_syscall3(__NR_lseek, fd, offset, whence);
1594 static __attribute__((unused))
1595 int sys_mkdir(const char *path, mode_t mode)
1598 return my_syscall3(__NR_mkdirat, AT_FDCWD, path, mode);
1599 #elif defined(__NR_mkdir)
1600 return my_syscall2(__NR_mkdir, path, mode);
1602 #error Neither __NR_mkdirat nor __NR_mkdir defined, cannot implement sys_mkdir()
1606 static __attribute__((unused))
1607 long sys_mknod(const char *path, mode_t mode, dev_t dev)
1610 return my_syscall4(__NR_mknodat, AT_FDCWD, path, mode, dev);
1611 #elif defined(__NR_mknod)
1612 return my_syscall3(__NR_mknod, path, mode, dev);
1614 #error Neither __NR_mknodat nor __NR_mknod defined, cannot implement sys_mknod()
1618 static __attribute__((unused))
1619 int sys_mount(const char *src, const char *tgt, const char *fst,
1620 unsigned long flags, const void *data)
1622 return my_syscall5(__NR_mount, src, tgt, fst, flags, data);
1625 static __attribute__((unused))
1626 int sys_open(const char *path, int flags, mode_t mode)
1629 return my_syscall4(__NR_openat, AT_FDCWD, path, flags, mode);
1630 #elif defined(__NR_open)
1631 return my_syscall3(__NR_open, path, flags, mode);
1633 #error Neither __NR_openat nor __NR_open defined, cannot implement sys_open()
1637 static __attribute__((unused))
1638 int sys_pivot_root(const char *new, const char *old)
1640 return my_syscall2(__NR_pivot_root, new, old);
1643 static __attribute__((unused))
1644 int sys_poll(struct pollfd *fds, int nfds, int timeout)
1646 #if defined(__NR_ppoll)
1650 t.tv_sec = timeout / 1000;
1651 t.tv_nsec = (timeout % 1000) * 1000000;
1653 return my_syscall4(__NR_ppoll, fds, nfds, (timeout >= 0) ? &t : NULL, NULL);
1654 #elif defined(__NR_poll)
1655 return my_syscall3(__NR_poll, fds, nfds, timeout);
1657 #error Neither __NR_ppoll nor __NR_poll defined, cannot implement sys_poll()
1661 static __attribute__((unused))
1662 ssize_t sys_read(int fd, void *buf, size_t count)
1664 return my_syscall3(__NR_read, fd, buf, count);
1667 static __attribute__((unused))
1668 ssize_t sys_reboot(int magic1, int magic2, int cmd, void *arg)
1670 return my_syscall4(__NR_reboot, magic1, magic2, cmd, arg);
1673 static __attribute__((unused))
1674 int sys_sched_yield(void)
1676 return my_syscall0(__NR_sched_yield);
1679 static __attribute__((unused))
1680 int sys_select(int nfds, fd_set *rfds, fd_set *wfds, fd_set *efds, struct timeval *timeout)
1682 #if defined(__ARCH_WANT_SYS_OLD_SELECT) && !defined(__NR__newselect)
1683 struct sel_arg_struct {
1687 } arg = { .n = nfds, .r = rfds, .w = wfds, .e = efds, .t = timeout };
1688 return my_syscall1(__NR_select, &arg);
1689 #elif defined(__ARCH_WANT_SYS_PSELECT6) && defined(__NR_pselect6)
1693 t.tv_sec = timeout->tv_sec;
1694 t.tv_nsec = timeout->tv_usec * 1000;
1696 return my_syscall6(__NR_pselect6, nfds, rfds, wfds, efds, timeout ? &t : NULL, NULL);
1697 #elif defined(__NR__newselect) || defined(__NR_select)
1698 #ifndef __NR__newselect
1699 #define __NR__newselect __NR_select
1701 return my_syscall5(__NR__newselect, nfds, rfds, wfds, efds, timeout);
1703 #error None of __NR_select, __NR_pselect6, nor __NR__newselect defined, cannot implement sys_select()
1707 static __attribute__((unused))
1708 int sys_setpgid(pid_t pid, pid_t pgid)
1710 return my_syscall2(__NR_setpgid, pid, pgid);
1713 static __attribute__((unused))
1714 pid_t sys_setsid(void)
1716 return my_syscall0(__NR_setsid);
1719 static __attribute__((unused))
1720 int sys_stat(const char *path, struct stat *buf)
1722 struct sys_stat_struct stat;
1725 #ifdef __NR_newfstatat
1726 /* only solution for arm64 */
1727 ret = my_syscall4(__NR_newfstatat, AT_FDCWD, path, &stat, 0);
1728 #elif defined(__NR_stat)
1729 ret = my_syscall2(__NR_stat, path, &stat);
1731 #error Neither __NR_newfstatat nor __NR_stat defined, cannot implement sys_stat()
1733 buf->st_dev = stat.st_dev;
1734 buf->st_ino = stat.st_ino;
1735 buf->st_mode = stat.st_mode;
1736 buf->st_nlink = stat.st_nlink;
1737 buf->st_uid = stat.st_uid;
1738 buf->st_gid = stat.st_gid;
1739 buf->st_rdev = stat.st_rdev;
1740 buf->st_size = stat.st_size;
1741 buf->st_blksize = stat.st_blksize;
1742 buf->st_blocks = stat.st_blocks;
1743 buf->st_atime = stat.st_atime;
1744 buf->st_mtime = stat.st_mtime;
1745 buf->st_ctime = stat.st_ctime;
1750 static __attribute__((unused))
1751 int sys_symlink(const char *old, const char *new)
1753 #ifdef __NR_symlinkat
1754 return my_syscall3(__NR_symlinkat, old, AT_FDCWD, new);
1755 #elif defined(__NR_symlink)
1756 return my_syscall2(__NR_symlink, old, new);
1758 #error Neither __NR_symlinkat nor __NR_symlink defined, cannot implement sys_symlink()
1762 static __attribute__((unused))
1763 mode_t sys_umask(mode_t mode)
1765 return my_syscall1(__NR_umask, mode);
1768 static __attribute__((unused))
1769 int sys_umount2(const char *path, int flags)
1771 return my_syscall2(__NR_umount2, path, flags);
1774 static __attribute__((unused))
1775 int sys_unlink(const char *path)
1777 #ifdef __NR_unlinkat
1778 return my_syscall3(__NR_unlinkat, AT_FDCWD, path, 0);
1779 #elif defined(__NR_unlink)
1780 return my_syscall1(__NR_unlink, path);
1782 #error Neither __NR_unlinkat nor __NR_unlink defined, cannot implement sys_unlink()
1786 static __attribute__((unused))
1787 pid_t sys_wait4(pid_t pid, int *status, int options, struct rusage *rusage)
1789 return my_syscall4(__NR_wait4, pid, status, options, rusage);
1792 static __attribute__((unused))
1793 pid_t sys_waitpid(pid_t pid, int *status, int options)
1795 return sys_wait4(pid, status, options, 0);
1798 static __attribute__((unused))
1799 pid_t sys_wait(int *status)
1801 return sys_waitpid(-1, status, 0);
1804 static __attribute__((unused))
1805 ssize_t sys_write(int fd, const void *buf, size_t count)
1807 return my_syscall3(__NR_write, fd, buf, count);
1811 /* Below are the libc-compatible syscalls which return x or -1 and set errno.
1812 * They rely on the functions above. Similarly they're marked static so that it
1813 * is possible to assign pointers to them if needed.
1816 static __attribute__((unused))
1819 void *ret = sys_brk(addr);
1828 static __attribute__((noreturn,unused))
1829 void exit(int status)
1834 static __attribute__((unused))
1835 int chdir(const char *path)
1837 int ret = sys_chdir(path);
1846 static __attribute__((unused))
1847 int chmod(const char *path, mode_t mode)
1849 int ret = sys_chmod(path, mode);
1858 static __attribute__((unused))
1859 int chown(const char *path, uid_t owner, gid_t group)
1861 int ret = sys_chown(path, owner, group);
1870 static __attribute__((unused))
1871 int chroot(const char *path)
1873 int ret = sys_chroot(path);
1882 static __attribute__((unused))
1885 int ret = sys_close(fd);
1894 static __attribute__((unused))
1897 int ret = sys_dup(fd);
1906 static __attribute__((unused))
1907 int dup2(int old, int new)
1909 int ret = sys_dup2(old, new);
1919 static __attribute__((unused))
1920 int dup3(int old, int new, int flags)
1922 int ret = sys_dup3(old, new, flags);
1932 static __attribute__((unused))
1933 int execve(const char *filename, char *const argv[], char *const envp[])
1935 int ret = sys_execve(filename, argv, envp);
1944 static __attribute__((unused))
1947 pid_t ret = sys_fork();
1956 static __attribute__((unused))
1959 int ret = sys_fsync(fd);
1968 static __attribute__((unused))
1969 int getdents64(int fd, struct linux_dirent64 *dirp, int count)
1971 int ret = sys_getdents64(fd, dirp, count);
1980 static __attribute__((unused))
1981 pid_t getpgid(pid_t pid)
1983 pid_t ret = sys_getpgid(pid);
1992 static __attribute__((unused))
1995 pid_t ret = sys_getpgrp();
2004 static __attribute__((unused))
2007 pid_t ret = sys_getpid();
2016 static __attribute__((unused))
2017 int gettimeofday(struct timeval *tv, struct timezone *tz)
2019 int ret = sys_gettimeofday(tv, tz);
2028 static __attribute__((unused))
2029 int ioctl(int fd, unsigned long req, void *value)
2031 int ret = sys_ioctl(fd, req, value);
2040 static __attribute__((unused))
2041 int kill(pid_t pid, int signal)
2043 int ret = sys_kill(pid, signal);
2052 static __attribute__((unused))
2053 int link(const char *old, const char *new)
2055 int ret = sys_link(old, new);
2064 static __attribute__((unused))
2065 off_t lseek(int fd, off_t offset, int whence)
2067 off_t ret = sys_lseek(fd, offset, whence);
2076 static __attribute__((unused))
2077 int mkdir(const char *path, mode_t mode)
2079 int ret = sys_mkdir(path, mode);
2088 static __attribute__((unused))
2089 int mknod(const char *path, mode_t mode, dev_t dev)
2091 int ret = sys_mknod(path, mode, dev);
2100 static __attribute__((unused))
2101 int mount(const char *src, const char *tgt,
2102 const char *fst, unsigned long flags,
2105 int ret = sys_mount(src, tgt, fst, flags, data);
2114 static __attribute__((unused))
2115 int open(const char *path, int flags, mode_t mode)
2117 int ret = sys_open(path, flags, mode);
2126 static __attribute__((unused))
2127 int pivot_root(const char *new, const char *old)
2129 int ret = sys_pivot_root(new, old);
2138 static __attribute__((unused))
2139 int poll(struct pollfd *fds, int nfds, int timeout)
2141 int ret = sys_poll(fds, nfds, timeout);
2150 static __attribute__((unused))
2151 ssize_t read(int fd, void *buf, size_t count)
2153 ssize_t ret = sys_read(fd, buf, count);
2162 static __attribute__((unused))
2165 int ret = sys_reboot(LINUX_REBOOT_MAGIC1, LINUX_REBOOT_MAGIC2, cmd, 0);
2174 static __attribute__((unused))
2175 void *sbrk(intptr_t inc)
2179 /* first call to find current end */
2180 if ((ret = sys_brk(0)) && (sys_brk(ret + inc) == ret + inc))
2187 static __attribute__((unused))
2188 int sched_yield(void)
2190 int ret = sys_sched_yield();
2199 static __attribute__((unused))
2200 int select(int nfds, fd_set *rfds, fd_set *wfds, fd_set *efds, struct timeval *timeout)
2202 int ret = sys_select(nfds, rfds, wfds, efds, timeout);
2211 static __attribute__((unused))
2212 int setpgid(pid_t pid, pid_t pgid)
2214 int ret = sys_setpgid(pid, pgid);
2223 static __attribute__((unused))
2226 pid_t ret = sys_setsid();
2235 static __attribute__((unused))
2236 unsigned int sleep(unsigned int seconds)
2238 struct timeval my_timeval = { seconds, 0 };
2240 if (sys_select(0, 0, 0, 0, &my_timeval) < 0)
2241 return my_timeval.tv_sec + !!my_timeval.tv_usec;
2246 static __attribute__((unused))
2247 int msleep(unsigned int msecs)
2249 struct timeval my_timeval = { msecs / 1000, (msecs % 1000) * 1000 };
2251 if (sys_select(0, 0, 0, 0, &my_timeval) < 0)
2252 return (my_timeval.tv_sec * 1000) +
2253 (my_timeval.tv_usec / 1000) +
2254 !!(my_timeval.tv_usec % 1000);
2259 static __attribute__((unused))
2260 int stat(const char *path, struct stat *buf)
2262 int ret = sys_stat(path, buf);
2271 static __attribute__((unused))
2272 int symlink(const char *old, const char *new)
2274 int ret = sys_symlink(old, new);
2283 static __attribute__((unused))
2284 int tcsetpgrp(int fd, pid_t pid)
2286 return ioctl(fd, TIOCSPGRP, &pid);
2289 static __attribute__((unused))
2290 mode_t umask(mode_t mode)
2292 return sys_umask(mode);
2295 static __attribute__((unused))
2296 int umount2(const char *path, int flags)
2298 int ret = sys_umount2(path, flags);
2307 static __attribute__((unused))
2308 int unlink(const char *path)
2310 int ret = sys_unlink(path);
2319 static __attribute__((unused))
2320 pid_t wait4(pid_t pid, int *status, int options, struct rusage *rusage)
2322 pid_t ret = sys_wait4(pid, status, options, rusage);
2331 static __attribute__((unused))
2332 pid_t waitpid(pid_t pid, int *status, int options)
2334 pid_t ret = sys_waitpid(pid, status, options);
2343 static __attribute__((unused))
2344 pid_t wait(int *status)
2346 pid_t ret = sys_wait(status);
2355 static __attribute__((unused))
2356 ssize_t write(int fd, const void *buf, size_t count)
2358 ssize_t ret = sys_write(fd, buf, count);
2367 /* some size-optimized reimplementations of a few common str* and mem*
2368 * functions. They're marked static, except memcpy() and raise() which are used
2369 * by libgcc on ARM, so they are marked weak instead in order not to cause an
2370 * error when building a program made of multiple files (not recommended).
2373 static __attribute__((unused))
2374 void *memmove(void *dst, const void *src, size_t len)
2376 ssize_t pos = (dst <= src) ? -1 : (long)len;
2380 pos += (dst <= src) ? 1 : -1;
2381 ((char *)dst)[pos] = ((char *)src)[pos];
2386 static __attribute__((unused))
2387 void *memset(void *dst, int b, size_t len)
2396 static __attribute__((unused))
2397 int memcmp(const void *s1, const void *s2, size_t n)
2402 while (ofs < n && !(c1 = ((char *)s1)[ofs] - ((char *)s2)[ofs])) {
2408 static __attribute__((unused))
2409 char *strcpy(char *dst, const char *src)
2413 while ((*dst++ = *src++));
2417 static __attribute__((unused))
2418 char *strchr(const char *s, int c)
2428 static __attribute__((unused))
2429 char *strrchr(const char *s, int c)
2431 const char *ret = NULL;
2441 static __attribute__((unused))
2442 size_t nolibc_strlen(const char *str)
2446 for (len = 0; str[len]; len++);
2450 #define strlen(str) ({ \
2451 __builtin_constant_p((str)) ? \
2452 __builtin_strlen((str)) : \
2453 nolibc_strlen((str)); \
2456 static __attribute__((unused))
2459 return (unsigned int)(c - '0') <= 9;
2462 static __attribute__((unused))
2463 long atol(const char *s)
2465 unsigned long ret = 0;
2482 return neg ? -ret : ret;
2485 static __attribute__((unused))
2486 int atoi(const char *s)
2491 static __attribute__((unused))
2492 const char *ltoa(long in)
2494 /* large enough for -9223372036854775808 */
2495 static char buffer[21];
2496 char *pos = buffer + sizeof(buffer) - 1;
2498 unsigned long n = neg ? -in : in;
2502 *pos-- = '0' + n % 10;
2513 __attribute__((weak,unused))
2514 void *memcpy(void *dst, const void *src, size_t len)
2516 return memmove(dst, src, len);
2519 /* needed by libgcc for divide by zero */
2520 __attribute__((weak,unused))
2521 int raise(int signal)
2523 return kill(getpid(), signal);
2526 /* Here come a few helper functions */
2528 static __attribute__((unused))
2529 void FD_ZERO(fd_set *set)
2531 memset(set, 0, sizeof(*set));
2534 static __attribute__((unused))
2535 void FD_SET(int fd, fd_set *set)
2537 if (fd < 0 || fd >= FD_SETSIZE)
2539 set->fd32[fd / 32] |= 1 << (fd & 31);
2542 /* WARNING, it only deals with the 4096 first majors and 256 first minors */
2543 static __attribute__((unused))
2544 dev_t makedev(unsigned int major, unsigned int minor)
2546 return ((major & 0xfff) << 8) | (minor & 0xff);
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