eduOS/kernel/syscall.c
Stefan Lankes a125dd6dce add support to start elf binaries
- add ELF loader
- create heap on demand (on first touch)
- add system call to increase the heap
2015-01-18 20:31:32 +01:00

113 lines
3 KiB
C

/*
* Copyright (c) 2010, Stefan Lankes, RWTH Aachen University
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* * Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this
* software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE FOR ANY
* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include <eduos/stddef.h>
#include <eduos/stdio.h>
#include <eduos/tasks.h>
#include <eduos/errno.h>
#include <eduos/syscall.h>
#include <eduos/spinlock.h>
static int sys_write(int fd, const char* buf, size_t len)
{
//TODO: Currently, we ignore the file descriptor
if (BUILTIN_EXPECT(!buf, 0))
return -1;
kputs(buf);
return 0;
}
static int sys_sbrk(int incr)
{
task_t* task = current_task;
vma_t* heap = task->heap;
int ret;
spinlock_lock(&task->vma_lock);
if (BUILTIN_EXPECT(!heap,0 )) {
kprintf("sys_sbrk: missing heap!\n");
abort();
}
ret = heap->end;
heap->end += incr;
if (heap->end < heap->start)
heap->end = heap->start;
// allocation and mapping of new pages for the heap
// is catched by the pagefault handler
spinlock_unlock(&task->vma_lock);
return ret;
}
int syscall_handler(uint32_t sys_nr, ...)
{
int ret = -EINVAL;
va_list vl;
va_start(vl, sys_nr);
switch(sys_nr)
{
case __NR_exit:
sys_exit(va_arg(vl, uint32_t));
ret = 0;
break;
case __NR_write: {
int fd = va_arg(vl, int);
const char* buf = va_arg(vl, const char*);
size_t len = va_arg(vl, size_t);
ret = sys_write(fd, buf, len);
break;
}
//TODO: Currently, we ignore file descriptors
case __NR_open:
case __NR_close:
ret = 0;
break;
case __NR_sbrk: {
int incr = va_arg(vl, int);
ret = sys_sbrk(incr);
break;
}
default:
kprintf("invalid system call: %u\n", sys_nr);
ret = -ENOSYS;
break;
};
va_end(vl);
return ret;
}