Mark
127 lines
3.5 KiB
C
127 lines
3.5 KiB
C
#include "bits/syscall.h"
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#include "bits/global.h"
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#include <errno.h>
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#define ASM_REGISTER(name) \
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register uint64_t name asm (#name)
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#define ASM_SYSCALL0(r0) ({ \
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ASM_REGISTER(rax) = (uint64_t) (r0); \
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asm volatile ("syscall":::"memory"); \
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rax; \
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})
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#define ASM_SYSCALL1(r0, r1) ({ \
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ASM_REGISTER(rdi) = (uint64_t) (r1); \
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/*
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* Should be the last one because memory accesses for arguments
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* fuck up %rax
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*/ \
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ASM_REGISTER(rax) = (uint64_t) (r0); \
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asm volatile ("syscall":::"memory"); \
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rax; \
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})
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#define ASM_SYSCALL2(r0, r1, r2) ({ \
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ASM_REGISTER(rdi) = (uint64_t) (r1); \
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ASM_REGISTER(rsi) = (uint64_t) (r2); \
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/*
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* Should be the last one because memory accesses for arguments
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* fuck up %rax
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*/ \
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ASM_REGISTER(rax) = (uint64_t) (r0); \
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asm volatile ("syscall":::"memory", "rax", "rdi", "rsi", "rdx"); \
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rax; \
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})
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#define ASM_SYSCALL3(r0, r1, r2, r3) ({ \
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ASM_REGISTER(rdi) = (uint64_t) (r1); \
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ASM_REGISTER(rsi) = (uint64_t) (r2); \
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ASM_REGISTER(rdx) = (uint64_t) (r3); \
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/*
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* Should be the last one because memory accesses for arguments
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* fuck up %rax
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*/ \
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ASM_REGISTER(rax) = (uint64_t) (r0); \
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asm volatile ("syscall":::"memory", "rax", "rdi", "rsi", "rdx"); \
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rax; \
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})
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#define SET_ERRNO(t, r) ({ \
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t res = (t) r; \
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if (res < 0) { \
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errno = -res; \
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} \
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((int) res) < 0 ? (t) -1 : res; \
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})
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ssize_t write(int fd, const void *buf, size_t count) {
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return SET_ERRNO(ssize_t, ASM_SYSCALL3(SYSCALL_NR_WRITE, fd, buf, count));
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}
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ssize_t read(int fd, void *buf, size_t count) {
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return SET_ERRNO(ssize_t, ASM_SYSCALL3(SYSCALL_NR_READ, fd, buf, count));
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}
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ssize_t sys_readdir(int fd, struct dirent *entp) {
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return SET_ERRNO(ssize_t, ASM_SYSCALL2(SYSCALL_NR_READDIR, fd, entp));
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}
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int open(const char *filename, int flags, int mode) {
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return SET_ERRNO(int, ASM_SYSCALL3(SYSCALL_NR_OPEN, filename, flags, mode));
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}
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void close(int fd) {
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(void) ASM_SYSCALL1(SYSCALL_NR_CLOSE, fd);
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}
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int stat(const char *filename, struct stat *st) {
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return SET_ERRNO(int, ASM_SYSCALL2(SYSCALL_NR_STAT, filename, st));
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}
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int brk(void *addr) {
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return SET_ERRNO(int, ASM_SYSCALL1(SYSCALL_NR_BRK, addr));
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}
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int fork(void) {
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return SET_ERRNO(int, ASM_SYSCALL0(SYSCALL_NR_FORK));
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}
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int execve(const char *filename, const char *const argv[], const char *const envp[]) {
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return SET_ERRNO(int, ASM_SYSCALL3(SYSCALL_NR_EXECVE, filename, argv, envp));
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}
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__attribute__((noreturn)) void exit(int code) {
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(void) ASM_SYSCALL1(SYSCALL_NR_EXIT, code);
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while (1);
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}
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int kill(int pid, int signum) {
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return SET_ERRNO(int, ASM_SYSCALL2(SYSCALL_NR_KILL, pid, signum));
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}
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void __kernel_signal(uintptr_t entry) {
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(void) ASM_SYSCALL1(SYSCALL_NRX_SIGNAL, entry);
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}
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__attribute__((noreturn)) void __kernel_sigret(void) {
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(void) ASM_SYSCALL0(SYSCALL_NRX_SIGRET);
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while (1);
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}
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// Although sbrk() is implemented in userspace, I guess it should also be here
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void *sbrk(intptr_t inc) {
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if (inc == 0) {
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return __cur_brk;
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}
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void *new_brk = (void *) ((uintptr_t) __cur_brk + inc);
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printf("New brk = %p\n", new_brk);
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if (brk(new_brk) != 0) {
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return __cur_brk;
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} else {
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return __cur_brk = new_brk;
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}
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}
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