path: root/tools/include/nolibc/sys.h

/* SPDX-License-Identifier: LGPL-2.1 OR MIT */
/*
 * Syscall definitions for NOLIBC (those in man(2))
 * Copyright (C) 2017-2021 Willy Tarreau <w@1wt.eu>
 */

#ifndef _NOLIBC_SYS_H
#define _NOLIBC_SYS_H

#include <stdarg.h>
#include "std.h"

/* system includes */
#include <asm/unistd.h>
#include <asm/signal.h>  /* for SIGCHLD */
#include <asm/ioctls.h>
#include <asm/mman.h>
#include <linux/fs.h>
#include <linux/loop.h>
#include <linux/time.h>
#include <linux/auxvec.h>
#include <linux/fcntl.h> /* for O_* and AT_* */
#include <linux/stat.h>  /* for statx() */
#include <linux/prctl.h>

#include "arch.h"
#include "errno.h"
#include "types.h"


/* Syscall return helper for library routines, set errno as -ret when ret is in
 * range of [-MAX_ERRNO, -1]
 *
 * Note, No official reference states the errno range here aligns with musl
 * (src/internal/syscall_ret.c) and glibc (sysdeps/unix/sysv/linux/sysdep.h)
 */

static __inline__ __attribute__((unused, always_inline))
long __sysret(unsigned long ret)
{
	if (ret >= (unsigned long)-MAX_ERRNO) {
		SET_ERRNO(-(long)ret);
		return -1;
	}
	return ret;
}

/* Functions in this file only describe syscalls. They're declared static so
 * that the compiler usually decides to inline them while still being allowed
 * to pass a pointer to one of their instances. Each syscall exists in two
 * versions:
 *   - the "internal" ones, which matches the raw syscall interface at the
 *     kernel level, which may sometimes slightly differ from the documented
 *     libc-level ones. For example most of them return either a valid value
 *     or -errno. All of these are prefixed with "sys_". They may be called
 *     by non-portable applications if desired.
 *
 *   - the "exported" ones, whose interface must closely match the one
 *     documented in man(2), that applications are supposed to expect. These
 *     ones rely on the internal ones, and set errno.
 *
 * Each syscall will be defined with the two functions, sorted in alphabetical
 * order applied to the exported names.
 *
 * In case of doubt about the relevance of a function here, only those which
 * set errno should be defined here. Wrappers like those appearing in man(3)
 * should not be placed here.
 */


/*
 * int brk(void *addr);
 * void *sbrk(intptr_t inc)
 */

static __attribute__((unused))
void *sys_brk(void *addr)
{
	return (void *)my_syscall1(__NR_brk, addr);
}

static __attribute__((unused))
int brk(void *addr)
{
	return __sysret(sys_brk(addr) ? 0 : -ENOMEM);
}

static __attribute__((unused))
void *sbrk(intptr_t inc)
{
	/* first call to find current end */
	void *ret = sys_brk(0);

	if (ret && sys_brk(ret + inc) == ret + inc)
		return ret + inc;

	return (void *)__sysret(-ENOMEM);
}


/*
 * int chdir(const char *path);
 */

static __attribute__((unused))
int sys_chdir(const char *path)
{
	return my_syscall1(__NR_chdir, path);
}

static __attribute__((unused))
int chdir(const char *path)
{
	return __sysret(sys_chdir(path));
}


/*
 * int chmod(const char *path, mode_t mode);
 */

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
	return -ENOSYS;
#endif
}

static __attribute__((unused))
int chmod(const char *path, mode_t mode)
{
	return __sysret(sys_chmod(path, mode));
}


/*
 * int chown(const char *path, uid_t owner, gid_t group);
 */

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
	return -ENOSYS;
#endif
}

static __attribute__((unused))
int chown(const char *path, uid_t owner, gid_t group)
{
	return __sysret(sys_chown(path, owner, group));
}


/*
 * int chroot(const char *path);
 */

static __attribute__((unused))
int sys_chroot(const char *path)
{
	return my_syscall1(__NR_chroot, path);
}

static __attribute__((unused))
int chroot(const char *path)
{
	return __sysret(sys_chroot(path));
}


/*
 * int close(int fd);
 */

static __attribute__((unused))
int sys_close