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linux_lab_os_exp2
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Merge branch 'master' of https://bdgit.educoder.net/po2ap8csw/linux_lab_os_exp2

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master
forever-learner 3 years ago
parent dcceacef1c 5831fcdc96
commit fc3a77a1ce
5 changed files with 274 additions and 288 deletions
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24
linux/include/linux/mm.h
Unescape View File

@ -1,10 +1,22 @@
#ifndef _MM_H
#define _MM_H
#define PAGE_SIZE 4096
#ifndef _mm_H
#define _mm_H
extern unsigned long get_free_page(void);
extern void calc_mem(void);
extern void mem_init(long start_mem, long end_mem);
extern void do_no_page(unsigned long error_code,unsigned long address);
extern int share_page(unsigned long address);
extern int try_to_share(unsigned long address, struct task_struct * p);
extern void get_empty_page(unsigned long address);
extern void write_verify(unsigned long address);
extern void do_wp_page(unsigned long error_code,unsigned long address);
extern void un_wp_page(unsigned long * table_entry);
extern unsigned long put_page(unsigned long page,unsigned long address);
extern int copy_page_tables(unsigned long from,unsigned long to,long size);
extern int free_page_tables(unsigned long from,unsigned long size);
extern void free_page(unsigned long addr);
#endif
extern unsigned long get_free_page(void);
extern void oom(void);
extern void do_exit(long code);
#endif // MACRO

181
linux/kernel/fork.c
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@ -36,7 +36,7 @@ void verify_area(void * addr,int size)
}
}
int copy_mem(int nr,struct task_struct * p,int flag)
int copy_mem(int nr,struct task_struct * p)
{
unsigned long old_data_base,new_data_base,data_limit;
unsigned long old_code_base,new_code_base,code_limit;
@ -53,7 +53,7 @@ int copy_mem(int nr,struct task_struct * p,int flag)
p->start_code = new_code_base;
set_base(p->ldt[1],new_code_base);
set_base(p->ldt[2],new_data_base);
if (copy_page_tables(old_data_base,new_data_base,data_limit,flag)) {
if (copy_page_tables(old_data_base,new_data_base,data_limit)) {
free_page_tables(new_data_base,data_limit);
return -ENOMEM;
}
@ -65,11 +65,12 @@ int copy_mem(int nr,struct task_struct * p,int flag)
* information (task[nr]) and sets up the necessary registers. It
* also copies the data segment in it's entirety.
*/
int copy_process(int flag,int nr,long ebp,long edi,long esi,long gs,long none,
int copy_process(int nr,long ebp,long edi,long esi,long gs,long none,
long ebx,long ecx,long edx,
long fs,long es,long ds,
long eip,long cs,long eflags,long esp,long ss)
{
sys_signal(SIGCHLD,NULL,NULL);
struct task_struct *p;
int i;
struct file *f;
@ -113,7 +114,7 @@ int copy_process(int flag,int nr,long ebp,long edi,long esi,long gs,long none,
p->tss.trace_bitmap = 0x80000000;
if (last_task_used_math == current)
__asm__("clts ; fnsave %0"::"m" (p->tss.i387));
if (copy_mem(nr,p,flag)) {
if (copy_mem(nr,p)) {
task[nr] = NULL;
free_page((long) p);
return -EAGAIN;
@ -147,95 +148,99 @@ int find_empty_process(void)
return -EAGAIN;
}
/*
直接让esp（子进程）指向另一个进程（当前进程）的地址；
修改eip对应的指令，改为ret 0xec8353c3 ps:应该只有0xc3有用
由于eip只执行一条指令，我们将eip指向栈，将ret压入栈即可；
在这里我们只实现了int (*fn)(void *) 一种函数类型，并且要求fn内以exit结尾
于是我们只需修改八字节即可；
下面写的不对，不能指向另一个进程的地址，只能修改物理页了。
*/
int do_clone(int nr,long tmp,int (*fn)(void *), void *child_stack, int flag)
int copy_mem_clone(int nr,struct task_struct * p)
{
//设置压栈表，方便操作；
long stack[1024];
unsigned long len=0;
task[nr]->tss.esp=(unsigned long) child_stack - 8;
stack[0] = (unsigned long) fn;
task[nr]->tss.eip = (unsigned long) child_stack - 4;
stack[1]= 0xec8353c3;
//栈区赋值；
len = 8;
char *p1=stack ,*p2=(char *)((unsigned long)child_stack-len);
while(len--)
put_fs_byte(*(p1++),p2++);
unsigned long old_data_base,new_data_base,data_limit;
unsigned long old_code_base,new_code_base,code_limit;
code_limit=get_limit(0x0f);
data_limit=get_limit(0x17);
old_code_base = get_base(current->ldt[1]);
old_data_base = get_base(current->ldt[2]);
if (old_data_base != old_code_base)
panic("We don't support separate I&D");
if (data_limit < code_limit)
panic("Bad data_limit");
new_data_base = new_code_base = nr * 0x4000000;
p->start_code = new_code_base;
set_base(p->ldt[1],new_code_base);
set_base(p->ldt[2],new_data_base);
if (copy_page_tables_clone(old_data_base,new_data_base,data_limit)) {
free_page_tables(new_data_base,data_limit);
return -ENOMEM;
}
return 0;
}
/*
共享物理页：写法有缺陷，可能child——stack跨页
//子进程task[nr]的页表项获取，目的是更新成child——stacK的物理页
nrfrom_page = ((address>>20) & 0xffc);
nrfrom_page += ((task[nr]->start_code>>20) & 0xffc);//页目录
nrfrom=*(unsigned long *)nrfrom_page; //页表项
if(!(nrfrom&1)) //无页表项分配一个
{
if(!(tpage=get_free_page()))
{
printk("out of memory.\n");
return -1;
}
else
{
*(unsigned long *)nrfrom_page= tpage | 7;
mem_map[(tpage-LOW_MEM)>>12]++;
}
}
nrfrom &= 0xfffff000;
nrfrom_page = nrfrom + ((address>>10) & 0xffc);
//获取child_stack的物理页,并将其复制给task[nr];
address=(unsigned long) child_stack;
from_page = ((address>>20) & 0xffc);
from_page += ((current->start_code>>20) & 0xffc);//页目录
if(!(*(unsigned long *)from_page&1)) //页表项不存在，申请页面
if(!(tpage=get_free_page()))
{
printk("out of memory.\n");
return -1;
}
else
{
*(unsigned long *)from_page= tpage | 7;
mem_map[(tpage-LOW_MEM)>>12]++;
}
from=*(unsigned long *)from_page; //页表项
from &= 0xfffff000;
from_page = from + ((address>>10) & 0xffc);
if(!(*(unsigned long *)from_page & 1)) //物理页不存在
if(!(tpage=get_free_page()))
{
printk("out of memory.\n");
return -1;
}
else
{
*(unsigned long *)from_page= tpage | 7;
mem_map[(tpage-LOW_MEM)>>12]++;
}
//复制给nr
*(unsigned long *)nrfrom_page = *(unsigned long *)from_page;
//更新esp,让其指向child_stack同样偏移的地点;
task[nr]->tss.esp=(unsigned long) child_stack;
//注意：这里child_stack 指向的是高地址，要向下面push.
unsigned long phy_addr = (*(unsigned long *)nrfrom_page & 0xfffff000) | ((unsigned long) child_stack & 0xfff);
if(argv)//参数列表不为空，将参数压入栈中，这里直接修改物理页
{
int copy_process_clone(int nr,long ebp,long edi,long esi,long gs,long none,
long ebx,long ecx,long edx,
long fs,long es,long ds,
long eip,long cs,long eflags,long esp,long ss)
{
struct task_struct *p;
int i;
struct file *f;
p = (struct task_struct *) get_free_page();
if (!p)
return -EAGAIN;
task[nr] = p;
__asm__ volatile ("cld"); /* by wyj */
*p = *current; /* NOTE! this doesn't copy the supervisor stack */
p->state = TASK_UNINTERRUPTIBLE;
p->pid = last_pid;
p->father = current->pid;
p->counter = p->priority;
p->signal = 0;
p->alarm = 0;
p->leader = 0; /* process leadership doesn't inherit */
p->utime = p->stime = 0;
p->cutime = p->cstime = 0;
p->start_time = jiffies;
p->tss.back_link = 0;
p->tss.esp0 = PAGE_SIZE + (long) p;
p->tss.ss0 = 0x10;
p->tss.eip = ebx;
p->tss.eflags = eflags;
p->tss.eax = 0;
p->tss.ecx = ecx;
p->tss.edx = edx;
p->tss.ebx = ebx;
p->tss.esp = ecx;
p->tss.ebp = ebp;
p->tss.esi = esi;
p->tss.edi = edi;
p->tss.es = es & 0xffff;
p->tss.cs = cs & 0xffff;
p->tss.ss = ss & 0xffff;
p->tss.ds = ds & 0xffff;
p->tss.fs = fs & 0xffff;
p->tss.gs = gs & 0xffff;
p->tss.ldt = _LDT(nr);
p->tss.trace_bitmap = 0x80000000;
if (last_task_used_math == current)
__asm__("clts ; fnsave %0"::"m" (p->tss.i387));
if (copy_mem_clone(nr,p)) {
task[nr] = NULL;
free_page((long) p);
return -EAGAIN;
}
//char * tmp1=nrfrom, *tmp2=child_stack-1024,len=;
//while()
return 0;
for (i=0; i<NR_OPEN;i++)
if (f=p->filp[i])
f->f_count++;
if (current->pwd)
current->pwd->i_count++;
if (current->root)
current->root->i_count++;
if (current->executable)
current->executable->i_count++;
set_tss_desc(gdt+(nr<<1)+FIRST_TSS_ENTRY,&(p->tss));
set_ldt_desc(gdt+(nr<<1)+FIRST_LDT_ENTRY,&(p->ldt));
p->state = TASK_RUNNING; /* do this last, just in case */
return last_pid;
}
*/

183
linux/kernel/sys.c
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@ -179,11 +179,7 @@ unsigned int sys_sleep(unsigned int seconds)
return 0;
}
int sys_clone()
{
return -1;
}
int sys_ftime()
{
@ -463,183 +459,4 @@ int sys_umask(int mask)
return (old);
}
static int my_share(unsigned long address, struct task_struct * p)
{
unsigned long from;
unsigned long to;
unsigned long from_page;
unsigned long to_page;
unsigned long phys_addr;
from_page = to_page = ((address>>20) & 0xffc);
from_page += ((current->start_code>>20) & 0xffc);
to_page += ((p->start_code>>20) & 0xffc);
from = *(unsigned long *) from_page;
from &= 0xfffff000;
from_page = from + ((address>>10) & 0xffc);
phys_addr = *(unsigned long *) from_page;
to = *(unsigned long *) to_page;
if (!(to & 1))
if (to = get_free_page())
*(unsigned long *) to_page = to | 7;
else
return 0;
to &= 0xfffff000;
to_page = to + ((address>>10) & 0xffc);
if (1 & *(unsigned long *) to_page)
return 0;
/* share them: write-protect */
*(unsigned long *) to_page = *(unsigned long *) from_page;
phys_addr -= LOW_MEM;
phys_addr >>= 12;
mem_map[phys_addr]++;
return 1;
}
// rememeber to sync when munmap exit manual
long sys_mmap(void * start,size_t len,...)// int prot,int flags,int fd,off_t off
{
printk("start mmaping\n");
/* va_list args;
va_start(args,len); */
int prot=3,flags=1,fd=3,off=0;
/* prot=va_arg(args,int);flags=va_arg(args,int);fd=va_arg(args,int);
off_t off=va_arg(args,off_t);
int *ll=&len;printk("%d,%d,%d,%d,%d\n",*ll,*(ll+1),*(ll+2),*(ll+3),*(ll+4));
va_end(args);
printk("%d,%d,%d,%ld\n",prot,flags,fd,off); */
int block;
size_t l=len;
struct buffer_head * bh;
char *temp,*p1,*p2;
void * buf=start;
int tempprot=0;
//因为new.h和namei.c定义不一样，要修改
if(prot &PROT_READ) tempprot |=4;
if(prot &PROT_EXEC) tempprot |=1;
if(prot &PROT_WRITE) tempprot |=2;
//特殊量len>0 off%4096==0 prot至少有read权限
if(len<=0 || off<0 || (off%PAGE_SIZE))
{
if(len<=0)
printk("the len of the wanting bytes must be positive");
else
printk("offset must be the mul of 4096");
return MAP_FAILED;
}
if(!(prot& PROT_READ)) return MAP_FAILED;
//permissions of the file ,搬运函数namei.c::permissions
printk("fd: %d\n",fd);
struct m_inode *inode=current->filp[fd]->f_inode;
printk("end of permissions\n");
int mode = inode->i_mode;
if (inode->i_dev && !inode->i_nlinks)
{printk("end of permissions1\n");return MAP_FAILED;}
else if (current->euid==inode->i_uid)
mode >>= 6;
else if (current->egid==inode->i_gid)
mode >>= 3;
if (!(((mode & tempprot & 0007) == tempprot) || suser()))
{
printk("error permission.");
return MAP_FAILED;
}
//end of permission check
printk("end of permissions\n");
//设置用户空间的虚拟地址，初始为32MB处，这样写在brk增长至32MB时会有bug,我们忽略
//同时，当栈向下增长到一定程度时，也会和当前地址冲突，我们忽略
if(start<=current->brk || start>=current->start_stack-0x8000 || start==NULL)
{
if(!current->mmap_tail)
buf=0x2000000;
else
buf=current->mmap_tail->endaddr;
}
//申请mmap
struct mmap_struct *mmap=(struct mmap_struct *)malloc(sizeof(struct mmap_struct));
mmap->address=buf;
mmap->size=len;
mmap->endaddr=(unsigned long)buf+(len + 0xfff)&0xfffff000;
mmap->rw=prot;
mmap->ps=flags;
mmap->next=NULL;
//加入current->mmap
if(!current->mmap)
{current->mmap=current->mmap_tail=mmap;}
else
current->mmap_tail->next=mmap;
printk("buf: %x\n",(unsigned long )buf);
//分配物理页
unsigned long from;
unsigned long to;
unsigned long from_page;
unsigned long to_page;
unsigned long phys_addr;
unsigned long tpage;
unsigned long address=mmap->address;
while(address<mmap->endaddr)
{
from_page = ((mmap->address>>20) & 0xffc);
from_page += ((current->start_code>>20) & 0xffc);//页目录
if(!(*(unsigned long *)from_page&1)) //页表项不存在，申请页面
if(!(tpage=get_free_page()))
{
printk("out of memory.\n");
return MAP_FAILED;
}
else
*(unsigned long *)from_page= tpage | 7;
from=*(unsigned long *)from_page; //页表项
from &= 0xfffff000;
from_page = from + ((address>>10) & 0xffc);
if(!(*(unsigned long *)from_page & 1)) //物理页不存在
if(!(tpage=get_free_page()))
{
printk("out of memory.\n");
return MAP_FAILED;
}
else
*(unsigned long *)from_page= tpage | 7;
*(unsigned long *)from_page &= (prot&PROT_WRITE); //分配读写权限
if(flags & MAP_SHARED)
{
struct task_struct ** p;
for (p = &LAST_TASK ; p > &FIRST_TASK ; --p) {
if (!*p)
continue;
if (current == *p)
continue;
if(!my_share(address,*p))
printk("share failed at task:pid=%d",(*p)->pid);
}
}
address+=PAGE_SIZE;
}
//read and put in
if (!(block = inode->i_zone[0]))
return NULL;
if (!(bh = bread(inode->i_dev,block)))
return NULL;
temp = (char *) bh->b_data;
p1=temp;p2=buf;
while(l--)
put_fs_byte(*(p1++),p2++);
printk("%s\n",temp);
return buf;
}
int sys_munmap()
{
return -1;
}

11
linux/kernel/system_call.s
Unescape View File

@ -227,9 +227,8 @@ sys_fork:
pushl %edi
pushl %ebp
pushl %eax
pushl $0x0 #for flag
call copy_process
addl $24,%esp #for flag
addl $20,%esp
1: ret
.align 4
@ -237,17 +236,13 @@ sys_clone:
call find_empty_process
testl %eax,%eax
js 1f
pushl %eax
push %gs
pushl %esi
pushl %edi
pushl %ebp
pushl %eax
pushl $0x1 #for flag
call copy_process
addl $24,%esp #for flag
call do_clone
addl $4,%esp
call copy_process_clone
addl $20,%esp
1: ret
hd_interrupt:

159
linux/mm/memory.c
Unescape View File

@ -147,7 +147,7 @@ int free_page_tables(unsigned long from,unsigned long size)
* 1 Mb-range, so the pages can be shared with the kernel. Thus the
* special case for nr=xxxx.
*/
int copy_page_tables(unsigned long from,unsigned long to,long size)
int copy_page_tables(unsigned long from,unsigned long to,long size )
{
unsigned long * from_page_table;
unsigned long * to_page_table;
@ -809,3 +809,160 @@ mytag:
/*
直接让esp（子进程）指向另一个进程（当前进程）的地址；
修改eip对应的指令，改为ret 0xec8353c3 ps:应该只有0xc3有用
由于eip只执行一条指令，我们将eip指向栈，将ret压入栈即可；
在这里我们只实现了int (*fn)(void *) 一种函数类型，并且要求fn内以exit结尾
于是我们只需修改八字节即可；
下面写的不对，不能指向另一个进程的地址，只能修改物理页了。
*/
/* int do_clone(int nr,long tmp,int (*fn)(void *), void *child_stack, int flag)
{
//设置压栈表，方便操作；
long stack[1024];
unsigned long len=0;
task[nr]->tss.esp=(unsigned long) child_stack - 8;
stack[0] = (unsigned long) fn;
task[nr]->tss.eip = (unsigned long) child_stack - 4;
stack[1]= 0xec8353c3;
//栈区赋值；
len = 8;
char *p1=stack ,*p2=(char *)((unsigned long)child_stack-len);
while(len--)
put_fs_byte(*(p1++),p2++);
return 0;
} */
/* child_stack-4 00 00 00 00 */
/* child_stack-8 00 00 00 00 */
/* child_stack-12 arg */
/* child_stack-16 fn */ //esp
/* child_stack-20 00 00 00 00 */
/* child_stack-24 00 00 00 00 */
/* child_stack-28 00 00 00 00 */
/* child_stack-32 0x000000c3 */
/*
int do_clone(int nr,long tmp,int (*fn)(void *), void *child_stack, int flag)
{
void * argv =NULL;
//共享物理页：写法有缺陷，可能child——stack跨页
//子进程task[nr]的页表项获取，目的是更新成child——stacK的物理页
unsigned long nrfrom_page,nrfrom,from_page,from,tpage,address;
address = task[nr]->tss.esp;
nrfrom_page = ((address>>20) & 0xffc);
nrfrom_page += ((task[nr]->start_code>>20) & 0xffc);//页目录
nrfrom=*(unsigned long *)nrfrom_page; //页表项
if(!(nrfrom&1)) //无页表项分配一个
{
if(!(tpage=get_free_page()))
{
printk("out of memory.\n");
return -1;
}
else
{
*(unsigned long *)nrfrom_page= tpage | 7;
mem_map[(tpage-LOW_MEM)>>12]++;
}
}
nrfrom &= 0xfffff000;
nrfrom_page = nrfrom + ((address>>10) & 0xffc);
//获取child_stack的物理页,并将其复制给task[nr];
address=(unsigned long) child_stack;
from_page = ((address>>20) & 0xffc);
from_page += ((current->start_code>>20) & 0xffc);//页目录
if(!(*(unsigned long *)from_page&1)) //页表项不存在，申请页面
if(!(tpage=get_free_page()))
{
printk("out of memory.\n");
return -1;
}
else
{
*(unsigned long *)from_page= tpage | 7;
mem_map[(tpage-LOW_MEM)>>12]++;
}
from=*(unsigned long *)from_page; //页表项
from &= 0xfffff000;
from_page = from + ((address>>10) & 0xffc);
if(!(*(unsigned long *)from_page & 1)) //物理页不存在
if(!(tpage=get_free_page()))
{
printk("out of memory.\n");
return -1;
}
else
{
*(unsigned long *)from_page= tpage | 7;
mem_map[(tpage-LOW_MEM)>>12]++;
}
//复制给nr
*(unsigned long *)nrfrom_page = *(unsigned long *)from_page;
unsigned long stack[128];
unsigned long off=(unsigned long)child_stack & 0xfff;
if(off < 32)
{
printk("地址跨页,我也没办法.\n");
return -1;
}
//更新esp,让其指向child_stack同样偏移的地点;
//注意：这里child_stack 指向的是高地址，要向下面push.
task[nr]->tss.esp &=0xfffff000;
task[nr]->tss.esp |=off - 16;
//eip 只有一条ret //所以传进来的fn必须以exit结尾，不能return ,
//因为我不会return这个玩意push ebp 又pop 啥的
task[nr]->tss.eip &=0xfffff000;
task[nr]->tss.eip |=off - 32;
//ret eip
stack[0]=0x000000c3;
stack[4]=(unsigned long)fn;
stack[5]=(unsigned long)argv;
char * p1=stack, *p2=(unsigned long) child_stack - 32,len=32;
while(len--)
put_fs_byte(*(p1++),p2++);
printk("nr:%d::fn:%x\n",nr,(unsigned long )fn);
return 0;
}
*/
int copy_page_tables_clone(unsigned long from,unsigned long to,long size )
{
unsigned long * from_page_table;
unsigned long * to_page_table;
unsigned long this_page;
unsigned long * from_dir, * to_dir;
unsigned long nr;
if ((from&0x3fffff) || (to&0x3fffff))
panic("copy_page_tables called with wrong alignment");
from_dir = (unsigned long *) ((from>>20) & 0xffc); /* _pg_dir = 0 */
to_dir = (unsigned long *) ((to>>20) & 0xffc);
size = ((unsigned) (size+0x3fffff)) >> 22;
for( ; size-->0 ; from_dir++,to_dir++) {
if (1 & *to_dir)
panic("copy_page_tables: already exist");
if (!(1 & *from_dir))
continue;
from_page_table = (unsigned long *) (0xfffff000 & *from_dir);
if (!(to_page_table = (unsigned long *) get_free_page()))
return -1; /* Out of memory, see freeing */
*to_dir = ((unsigned long) to_page_table) | 7;
nr = (from==0)?0xA0:1024;
for ( ; nr-- > 0 ; from_page_table++,to_page_table++) {
this_page = *from_page_table;
if (!(1 & this_page))
continue;
*to_page_table = this_page;
if (this_page > LOW_MEM) {
*from_page_table = this_page;
this_page -= LOW_MEM;
this_page >>= 12;
mem_map[this_page]++;
}
}
}
invalidate();
return 0;
}
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