idk wip

source/sys/syscalls.c

@@ -0,0 +1,177 @@
+// SPDX-License-Identifier: CC0-1.0
+//
+// SPDX-FileContributor: Antonio Niño Díaz, 2022
+
+#include <errno.h>
+#include <sys/stat.h>
+#include <sys/times.h>
+#include <time.h>
+
+// This file implements stubs for system calls. For more information about it,
+// check the documentation of newlib:
+//
+//     https://sourceware.org/newlib/libc.html#Syscalls
+
+#undef errno
+extern int errno;
+
+char *__env[1] = { 0 };
+char **environ = __env;
+
+int _getpid(void)
+{
+    return 1;
+}
+
+int _kill(int pid, int sig)
+{
+    (void)pid;
+    (void)sig;
+
+    errno = EINVAL;
+    return -1;
+}
+
+void _exit(int status)
+{
+    _kill(status, -1);
+
+    // Hang, there is nowhere to go
+    while (1);
+}
+
+__attribute__((weak)) int _read(int file, char *ptr, int len)
+{
+    (void)file;
+    (void)ptr;
+
+    return len;
+}
+
+__attribute__((weak)) int _write(int file, char *ptr, int len)
+{
+    (void)file;
+    (void)ptr;
+
+    return len;
+}
+
+int _close(int file)
+{
+    (void)file;
+
+    return -1;
+}
+
+
+int _fstat(int file, struct stat *st)
+{
+    (void)file;
+
+    st->st_mode = S_IFCHR;
+    return 0;
+}
+
+int _isatty(int file)
+{
+    (void)file;
+
+    return 1;
+}
+
+int _lseek(int file, int ptr, int dir)
+{
+    (void)file;
+    (void)ptr;
+    (void)dir;
+
+    return 0;
+}
+
+int _open(char *path, int flags, ...)
+{
+    (void)path;
+    (void)flags;
+
+    return -1;
+}
+
+int _wait(int *status)
+{
+    (void)status;
+
+    errno = ECHILD;
+    return -1;
+}
+
+int _unlink(char *name)
+{
+    (void)name;
+
+    errno = ENOENT;
+    return -1;
+}
+
+int _times(struct tms *buf)
+{
+    (void)buf;
+
+    return -1;
+}
+
+int _stat(char *file, struct stat *st)
+{
+    (void)file;
+
+    st->st_mode = S_IFCHR;
+    return 0;
+}
+
+int _link(char *old, char *new)
+{
+    (void)old;
+    (void)new;
+
+    errno = EMLINK;
+    return -1;
+}
+
+int _fork(void)
+{
+    errno = EAGAIN;
+    return -1;
+}
+
+int _execve(char *name, char **argv, char **env)
+{
+    (void)name;
+    (void)argv;
+    (void)env;
+
+    errno = ENOMEM;
+    return -1;
+}
+
+void *_sbrk(int incr)
+{
+    // Symbols defined by the linker
+    extern char __HEAP_START__[];
+    extern char __HEAP_END__[];
+    const uintptr_t HEAP_START = (uintptr_t) __HEAP_START__;
+    const uintptr_t HEAP_END = (uintptr_t) __HEAP_END__;
+
+    // Pointer to the current end of the heap
+    static uintptr_t heap_end = HEAP_START;
+
+    if (heap_end + incr > HEAP_END)
+    {
+        errno = ENOMEM;
+        return (void *)-1;
+    }
+
+    uintptr_t prev_heap_end = heap_end;
+
+    heap_end += incr;
+
+    return (void *)prev_heap_end;
+}