183 lines
3.8 KiB
C
183 lines
3.8 KiB
C
#include "types.h"
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#include "stat.h"
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#include "param.h"
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#include "mmu.h"
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#include "proc.h"
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#include "defs.h"
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#include "x86.h"
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#include "traps.h"
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#include "syscall.h"
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#include "spinlock.h"
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#include "buf.h"
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#include "fs.h"
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#include "fsvar.h"
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#include "elf.h"
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#include "file.h"
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#include "fcntl.h"
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// User code makes a system call with INT T_SYSCALL.
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// System call number in %eax.
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// Arguments on the stack, from the user call to the C
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// library system call function. The saved user %esp points
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// to a saved program counter, and then the first argument.
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// Fetch the int at addr from process p.
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int
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fetchint(struct proc *p, uint addr, int *ip)
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{
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if(addr >= p->sz || addr+4 > p->sz)
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return -1;
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*ip = *(int*)(p->mem + addr);
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return 0;
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}
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// Fetch the nul-terminated string at addr from process p.
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// Doesn't actually copy the string - just sets *pp to point at it.
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// Returns length of string, not including nul.
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int
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fetchstr(struct proc *p, uint addr, char **pp)
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{
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char *cp, *ep;
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if(addr >= p->sz)
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return -1;
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*pp = p->mem + addr;
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ep = p->mem + p->sz;
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for(cp = *pp; cp < ep; cp++)
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if(*cp == 0)
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return cp - *pp;
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return -1;
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}
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// Fetch the argno'th word-sized system call argument as an integer.
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int
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argint(int argno, int *ip)
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{
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struct proc *p = curproc[cpu()];
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return fetchint(p, p->tf->esp + 4 + 4*argno, ip);
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}
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// Fetch the nth word-sized system call argument as a pointer
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// to a block of memory of size n bytes. Check that the pointer
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// lies within the process address space.
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int
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argptr(int argno, char **pp, int size)
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{
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int i;
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struct proc *p = curproc[cpu()];
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if(argint(argno, &i) < 0)
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return -1;
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if((uint)i >= p->sz || (uint)i+size >= p->sz)
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return -1;
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*pp = p->mem + i;
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return 0;
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}
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// Fetch the nth word-sized system call argument as a string pointer.
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// Check that the pointer is valid and the string is nul-terminated.
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// (There is no shared writable memory, so the string can't change
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// between this check and being used by the kernel.)
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int
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argstr(int argno, char **pp)
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{
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int addr;
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if(argint(argno, &addr) < 0)
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return -1;
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return fetchstr(curproc[cpu()], addr, pp);
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}
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extern int sys_chdir(void);
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extern int sys_close(void);
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extern int sys_dup(void);
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extern int sys_exec(void);
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extern int sys_exit(void);
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extern int sys_fork(void);
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extern int sys_fstat(void);
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extern int sys_getpid(void);
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extern int sys_kill(void);
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extern int sys_link(void);
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extern int sys_mkdir(void);
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extern int sys_mknod(void);
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extern int sys_open(void);
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extern int sys_pipe(void);
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extern int sys_read(void);
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extern int sys_sbrk(void);
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extern int sys_unlink(void);
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extern int sys_wait(void);
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extern int sys_write(void);
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void
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syscall(void)
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{
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struct proc *cp = curproc[cpu()];
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int num = cp->tf->eax;
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int ret = -1;
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switch(num){
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case SYS_fork:
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ret = sys_fork();
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break;
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case SYS_exit:
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ret = sys_exit();
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break;
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case SYS_wait:
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ret = sys_wait();
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break;
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case SYS_pipe:
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ret = sys_pipe();
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break;
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case SYS_write:
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ret = sys_write();
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break;
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case SYS_read:
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ret = sys_read();
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break;
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case SYS_close:
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ret = sys_close();
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break;
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case SYS_kill:
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ret = sys_kill();
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break;
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case SYS_exec:
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ret = sys_exec();
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break;
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case SYS_open:
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ret = sys_open();
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break;
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case SYS_mknod:
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ret = sys_mknod();
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break;
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case SYS_unlink:
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ret = sys_unlink();
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break;
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case SYS_fstat:
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ret = sys_fstat();
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break;
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case SYS_link:
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ret = sys_link();
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break;
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case SYS_mkdir:
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ret = sys_mkdir();
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break;
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case SYS_chdir:
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ret = sys_chdir();
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break;
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case SYS_dup:
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ret = sys_dup();
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break;
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case SYS_getpid:
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ret = sys_getpid();
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break;
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case SYS_sbrk:
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ret = sys_sbrk();
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break;
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default:
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cprintf("unknown sys call %d\n", num);
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// Maybe kill the process?
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break;
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}
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cp->tf->eax = ret;
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}
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