250 lines
11 KiB
C
250 lines
11 KiB
C
/**********************************************
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* exec.c add by visual 2016.5.23
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*************************************************/
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#include "type.h"
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#include "const.h"
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#include "protect.h"
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#include "string.h"
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#include "proc.h"
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#include "global.h"
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#include "proto.h"
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#include "elf.h"
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#include "fs.h" //added by mingxuan 2019-5-19
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#include "vfs.h"
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static u32 exec_elfcpy(u32 fd,Elf32_Phdr Echo_Phdr,u32 attribute);
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static u32 exec_load(u32 fd,const Elf32_Ehdr* Echo_Ehdr,const Elf32_Phdr Echo_Phdr[]);
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static int exec_pcb_init(char* path);
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/*======================================================================*
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* sys_exec add by visual 2016.5.23
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*exec系统调用功能实现部分
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*======================================================================*/
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u32 sys_exec(char *path)
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{
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Elf32_Ehdr *Echo_Ehdr = NULL;
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Elf32_Phdr *Echo_Phdr = NULL;
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u32 addr_lin;
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u32 err_temp;
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char* p_reg; //point to a register in the new kernel stack, added by xw, 17/12/11
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if( 0==path )
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{
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vga_write_str_color("exec: path ERROR!",0x74);
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return -1;
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}
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/*******************打开文件************************/
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// u32 fd = open(path,"r"); //deleted by mingxuan 2019-5-19
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u32 fd = do_vopen(path, O_RDWR); //deleted by mingxuan 2019-5-19
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if(fd==-1)
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{
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//printf("sys_exec open error!\n"); //deleted by mingxuan 2019-5-23
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return -1;
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}
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// u32 fd = fake_open(path,"r"); //modified by xw, 18/5/30
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/*************获取elf信息**************/
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Echo_Ehdr = sys_kmalloc(sizeof(Elf32_Ehdr));
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read_Ehdr(fd, Echo_Ehdr, 0);
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Echo_Phdr = sys_kmalloc(sizeof(Elf32_Phdr) * Echo_Ehdr->e_phnum);
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for (int i = 0 ; i < Echo_Ehdr->e_phnum ; i++)
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read_Phdr(fd, Echo_Phdr + i, Echo_Ehdr->e_phoff + i * sizeof(Elf32_Phdr));
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/*************释放进程内存****************/
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//目前还没有实现 思路是：数据、代码根据text_info和data_info属性决定释放深度，其余内存段可以完全释放
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/*************根据elf的program复制文件信息**************/
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if(-1==exec_load(fd,Echo_Ehdr,Echo_Phdr)) return -1;//使用了const指针传递
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/*****************重新初始化该进程的进程表信息（包括LDT）、线性地址布局、进程树属性********************/
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exec_pcb_init(path);
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/***********************代码、数据、堆、栈***************************/
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//代码、数据已经处理，将eip重置即可
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p_proc_current->task.regs.eip = Echo_Ehdr->e_entry;//进程入口线性地址
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p_reg = (char*)(p_proc_current + 1); //added by xw, 17/12/11
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*((u32*)(p_reg + EIPREG - P_STACKTOP)) = p_proc_current->task.regs.eip; //added by xw, 17/12/11
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//栈
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p_proc_current->task.regs.esp=(u32)p_proc_current->task.memmap.stack_lin_base; //栈地址最高处
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*((u32*)(p_reg + ESPREG - P_STACKTOP)) = p_proc_current->task.regs.esp; //added by xw, 17/12/11
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for( addr_lin=p_proc_current->task.memmap.stack_lin_base ; addr_lin > p_proc_current->task.memmap.stack_lin_limit ; addr_lin-=num_4K )
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{
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err_temp = lin_mapping_phy( addr_lin,//线性地址 //add by visual 2016.5.9
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MAX_UNSIGNED_INT,//物理地址 //edit by visual 2016.5.19
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p_proc_current->task.pid,//进程pid //edit by visual 2016.5.19
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PG_P | PG_USU | PG_RWW,//页目录的属性位
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PG_P | PG_USU | PG_RWW);//页表的属性位
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if( err_temp!=0 )
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{
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vga_write_str_color("kernel_main Error:lin_mapping_phy",0x74);
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return -1;
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}
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}
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//堆 用户还没有申请，所以没有分配，只在PCB表里标示了线性起始位置
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real_close(fd); //added by mingxuan 2019-5-23
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if (Echo_Ehdr != NULL)
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sys_free(Echo_Ehdr);
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if (Echo_Phdr != NULL)
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sys_free(Echo_Phdr);
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//vga_write_str_color("\n[exec success:",0x72);//灰底绿字
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//vga_write_str_color(path,0x72);//灰底绿字
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//vga_write_str_color("]",0x72);//灰底绿字
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return 0;
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}
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/*======================================================================*
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* exec_elfcpy add by visual 2016.5.23
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*复制elf中program到内存中
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*======================================================================*/
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static u32 exec_elfcpy(u32 fd,Elf32_Phdr Echo_Phdr,u32 attribute) // 这部分代码将来要移动到exec.c文件中，包括下面exec()中的一部分
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{
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u32 lin_addr = Echo_Phdr.p_vaddr;
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u32 lin_limit = Echo_Phdr.p_vaddr + Echo_Phdr.p_memsz;
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u32 file_offset = Echo_Phdr.p_offset;
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u32 file_limit = Echo_Phdr.p_offset + Echo_Phdr.p_filesz;
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char ch;
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//u32 pde_addr_phy = get_pde_phy_addr(p_proc_current->task.pid); //页目录物理地址 //delete by visual 2016.5.19
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//u32 addr_phy = do_malloc(Echo_Phdr.p_memsz);//申请物理内存 //delete by visual 2016.5.19
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for( ; lin_addr<lin_limit ; lin_addr++,file_offset++ )
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{
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lin_mapping_phy(lin_addr,MAX_UNSIGNED_INT,p_proc_current->task.pid,PG_P | PG_USU | PG_RWW/*说明*/,attribute);//说明：PDE属性尽量为读写，因为它要映射1024个物理页，可能既有数据，又有代码 //edit by visual 2016.5.19
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if( file_offset<file_limit )
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{//文件中还有数据，正常拷贝
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//modified by xw, 18/5/30
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// seek(file_offset);
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// read(fd,&ch,1);
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//fake_seek(file_offset); //deleted by mingxuan 2019-5-22
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//real_lseek(fd, file_offset, SEEK_SET); //modified by mingxuan 2019-5-22
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do_vlseek(fd, file_offset, SEEK_SET); //modified by mingxuan 2019-5-24
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//fake_read(fd,&ch,1); //deleted by mingxuan 2019-5-22
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//real_read(fd, &ch, 1); //modified by mingxuan 2019-5-22
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do_vread(fd, &ch, 1); //modified by mingxuan 2019-5-24
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//~xw
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*((u8*)lin_addr) = ch;//memcpy((void*)lin_addr,&ch,1);
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}
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else
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{
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//已初始化数据段拷贝完毕，剩下的是未初始化的数据段，在内存中填0
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*((u8*)lin_addr) = 0;//memset((void*)lin_addr,0,1);
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}
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}
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return 0;
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}
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/*======================================================================*
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* exec_load add by visual 2016.5.23
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*根据elf的program复制文件信息
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*======================================================================*/
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static u32 exec_load(u32 fd,const Elf32_Ehdr* Echo_Ehdr,const Elf32_Phdr Echo_Phdr[])
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{
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u32 ph_num;
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if( 0==Echo_Ehdr->e_phnum )
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{
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vga_write_str_color("exec_load: elf ERROR!",0x74);
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return -1;
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}
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// (This is bullshit)我们还不能确定elf中一共能有几个program，但就目前我们查看过的elf文件中，只出现过两中program，一种.text（R-E）和一种.data（RW-）
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// 上面一句话导致了去年出现了诡异的错误，暂时只能说简单修复了一下，但是这个系统的权限就很混乱
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for( ph_num=0; ph_num<Echo_Ehdr->e_phnum ; ph_num++ )
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{
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if( 0==Echo_Phdr[ph_num].p_memsz )
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{//最后一个program
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break;
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}
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if (Echo_Phdr[ph_num].p_flags & 0x1) // xx1，__E, executable seg must be code seg
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{//.text
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exec_elfcpy(fd,Echo_Phdr[ph_num],PG_P | PG_USU | PG_RWR);//进程代码段
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p_proc_current->task.memmap.text_lin_base = Echo_Phdr[ph_num].p_vaddr;
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p_proc_current->task.memmap.text_lin_limit = Echo_Phdr[ph_num].p_vaddr + Echo_Phdr[ph_num].p_memsz;
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}
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else if (Echo_Phdr[ph_num].p_flags & 0x4) // 1xx，R__, treat all readable but not executable segs as data seg, though some may be RW and some RO
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{//.data
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exec_elfcpy(fd,Echo_Phdr[ph_num],PG_P | PG_USU | PG_RWW);//进程数据段
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p_proc_current->task.memmap.data_lin_base = Echo_Phdr[ph_num].p_vaddr;
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p_proc_current->task.memmap.data_lin_limit = Echo_Phdr[ph_num].p_vaddr + Echo_Phdr[ph_num].p_memsz;
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}
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else
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{
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vga_write_str_color("exec_load: unKnown elf'program!",0x74);
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return -1;
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}
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}
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return 0;
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}
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/*======================================================================*
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* exec_init add by visual 2016.5.23
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* 重新初始化寄存器和特权级、线性地址布局
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*======================================================================*/
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static int exec_pcb_init(char* path)
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{
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char* p_regs; //point to registers in the new kernel stack, added by xw, 17/12/11
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//名称 状态 特权级 寄存器
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strncpy(p_proc_current->task.p_name, path, sizeof(p_proc_current->task.p_name) - 1); // 名称
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p_proc_current->task.stat = READY; //状态
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p_proc_current->task.ldts[0].attr1 = DA_C | PRIVILEGE_USER << 5;//特权级修改为用户级
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p_proc_current->task.ldts[1].attr1 = DA_DRW | PRIVILEGE_USER << 5;//特权级修改为用户级
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p_proc_current->task.regs.cs = ((8 * 0) & SA_RPL_MASK & SA_TI_MASK)| SA_TIL | RPL_USER;
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p_proc_current->task.regs.ds = ((8 * 1) & SA_RPL_MASK & SA_TI_MASK)| SA_TIL | RPL_USER;
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p_proc_current->task.regs.es = ((8 * 1) & SA_RPL_MASK & SA_TI_MASK)| SA_TIL | RPL_USER;
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p_proc_current->task.regs.fs = ((8 * 1) & SA_RPL_MASK & SA_TI_MASK)| SA_TIL | RPL_USER;
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p_proc_current->task.regs.ss = ((8 * 1) & SA_RPL_MASK & SA_TI_MASK)| SA_TIL | RPL_USER;
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p_proc_current->task.regs.gs = (SELECTOR_KERNEL_GS & SA_RPL_MASK)| RPL_USER;
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p_proc_current->task.regs.eflags = 0x202; /* IF=1,bit2 永远是1 */
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/***************copy registers data****************************/
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//copy registers data to the bottom of the new kernel stack
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//added by xw, 17/12/11
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p_regs = (char*)(p_proc_current + 1);
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p_regs -= P_STACKTOP;
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memcpy(p_regs, (char*)p_proc_current, 18 * 4);
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//进程表线性地址布局部分，text、data已经在前面初始化了
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p_proc_current->task.memmap.vpage_lin_base = VpageLinBase; //保留内存基址
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p_proc_current->task.memmap.vpage_lin_limit = VpageLinBase; //保留内存界限
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p_proc_current->task.memmap.heap_lin_base = HeapLinBase; //堆基址
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p_proc_current->task.memmap.heap_lin_limit = HeapLinBase; //堆界限
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p_proc_current->task.memmap.stack_child_limit = StackLinLimitMAX; //add by visual 2016.5.27
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p_proc_current->task.memmap.stack_lin_base = StackLinBase; //栈基址
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p_proc_current->task.memmap.stack_lin_limit = StackLinBase - 0x4000; //栈界限（使用时注意栈的生长方向）
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p_proc_current->task.memmap.arg_lin_base = ArgLinBase; //参数内存基址
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p_proc_current->task.memmap.arg_lin_limit = ArgLinBase; //参数内存界限
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p_proc_current->task.memmap.kernel_lin_base = KernelLinBase; //内核基址
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p_proc_current->task.memmap.kernel_lin_limit = KernelLinBase + KernelSize; //内核大小初始化为8M
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//进程树属性,只要改两项，其余不用改
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//p_proc_current->task.info.type = TYPE_PROCESS; //当前是进程还是线程
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//p_proc_current->task.info.real_ppid = -1; //亲父进程，创建它的那个进程
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//p_proc_current->task.info.ppid = -1; //当前父进程
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//p_proc_current->task.info.child_p_num = 0; //子进程数量
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//p_proc_current->task.info.child_process[NR_CHILD_MAX];//子进程列表
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//p_proc_current->task.info.child_t_num = 0; //子线程数量
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//p_proc_current->task.info.child_thread[NR_CHILD_MAX];//子线程列表
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p_proc_current->task.info.text_hold = 1; //是否拥有代码
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p_proc_current->task.info.data_hold = 1; //是否拥有数据
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return 0;
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}
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