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/** @file syscall_misc.c
*
* @brief miscellaneous syscalls.
*
* @author Hanjie Wu (hanjiew)
* @bug No functional bugs
*/
#include <simics.h>
#include <stdio.h>
#include <string.h>
#include <common_kern.h>
#include <elf/elf_410.h>
#include <malloc_internal.h>
#include <ureg.h>
#include <x86/asm.h>
#include <x86/cr.h>
#include <x86/eflags.h>
#include <x86/seg.h>
#include <asm_instr.h>
#include <assert.h>
#include <loader.h>
#include <malloc.h>
#include <mm.h>
#include <paging.h>
#include <sched.h>
#include <sync.h>
#include <timer.h>
#include <toad.h>
#include <usermem.h>
/**
* @brief misbehave() syscall handler
* @param f saved regs
*/
void sys_misbehave_real(stack_frame_t* f) {
f->eax = 0;
}
/**
* @brief halt() syscall handler
* @param f saved regs
*/
void sys_halt_real(stack_frame_t* f) {
sim_halt();
hlt();
panic("Halted");
}
/**
* @brief read the "." file to user buf
* @param buf buffer
* @param count size
* @param offset offset
* @return number of bytes read, or -1 on failure
*/
static reg_t read_dot_file(va_t buf, int count, int offset);
/**
* @brief readfile() syscall handler
* @param f saved regs
*/
void sys_readfile_real(stack_frame_t* f) {
reg_t esi = f->esi;
va_t pfilename, buf;
int count, offset;
if (copy_from_user((va_t)esi, sizeof(va_t), &pfilename) != 0) {
goto read_arg_fail;
}
if (copy_from_user((va_t)(esi + sizeof(va_t)), sizeof(va_t), &buf) != 0) {
goto read_arg_fail;
}
if (copy_from_user((va_t)(esi + 2 * sizeof(va_t)), sizeof(int), &count) !=
0) {
goto read_arg_fail;
}
if (copy_from_user((va_t)(esi + 3 * sizeof(va_t)), sizeof(int), &offset) !=
0) {
goto read_arg_fail;
}
if (count < 0 || offset < 0) {
goto read_arg_fail;
}
char* filename = copy_string_from_user(pfilename, MAX_EXECNAME_LEN);
if (filename == NULL) {
goto read_arg_fail;
}
if (strcmp(filename, ".") == 0) {
free(filename);
f->eax = read_dot_file(buf, count, offset);
return;
}
file_t* fp = find_file(filename);
if (fp == NULL) {
goto no_such_file;
}
free(filename);
if (offset > fp->execlen) {
goto offset_too_big;
}
int size = fp->execlen - offset;
if (count < size) {
size = count;
}
if (copy_to_user(buf, size, (void*)(fp->execbytes + offset)) != 0) {
goto bad_buffer;
}
f->eax = (reg_t)size;
return;
bad_buffer:
offset_too_big:
no_such_file:
free(filename);
read_arg_fail:
f->eax = (reg_t)-1;
return;
}
static reg_t read_dot_file(va_t buf, int count, int offset) {
file_t* fp;
int i = 0;
int cur = 0;
int written = 0, left = count;
while (i < exec2obj_userapp_count && left > 0) {
fp = &exec2obj_userapp_TOC[i];
int len = strlen(fp->execname) + 1;
if (cur + len <= offset) {
/* before offset */
cur += len;
i++;
continue;
}
int size = len;
const char* start = fp->execname;
/* write this entry to buffer */
if (cur < offset) {
size -= (offset - cur);
start += (offset - cur);
}
if (left < size) {
size = left;
}
if (copy_to_user((va_t)buf + written, size, (void*)start) != 0) {
return (reg_t)-1;
}
cur += len;
written += size;
left -= size;
i++;
}
/* write extra null byte */
if (left != 0 && cur == offset) {
char nul = '\0';
if (copy_to_user((va_t)buf + written, 1, &nul) != 0) {
return (reg_t)-1;
}
written++;
}
return (reg_t)written;
}
void sys_new_console_real(stack_frame_t* f) {
thread_t* t = get_current();
pts_t* old_pts = t->pts;
pts_t* pts = smalloc(sizeof(pts_t));
if (pts == NULL) {
f->eax = (reg_t)-1;
return;
}
pts_init(pts);
pts->refcount++;
t->pts = pts;
mutex_lock(&old_pts->lock);
old_pts->refcount--;
mutex_unlock(&old_pts->lock);
switch_pts(pts);
print_toad();
}
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