175 lines
3.2 KiB
C
175 lines
3.2 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 32 bits from a user-supplied pointer.
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// Returns 0 if addr was OK, -1 if illegal.
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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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*ip = 0;
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if(addr > p->sz - 4)
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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 byte from a user-supplied pointer.
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// Returns 0 on success, -1 if pointer is illegal.
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int
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fetchbyte(struct proc *p, uint addr, char *c)
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{
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if(addr >= p->sz)
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return -1;
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*c = *(p->mem + addr);
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return 0;
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}
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int
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fetcharg(int argno, void *ip)
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{
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uint esp;
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esp = (uint) curproc[cpu()]->tf->esp;
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return fetchint(curproc[cpu()], esp + 4 + 4*argno, ip);
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}
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// Check that an entire string is valid in user space.
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// Returns the length, not including null, or -1.
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int
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checkstring(uint s)
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{
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char c;
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int len = 0;
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while(1){
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if(fetchbyte(curproc[cpu()], s, &c) < 0)
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return -1;
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if(c == '\0')
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return len;
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len++;
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s++;
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}
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}
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int
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putint(struct proc *p, uint addr, int x)
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{
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if(addr > p->sz - 4)
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return -1;
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memmove(p->mem + addr, &x, 4);
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return 0;
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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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// XXX fault
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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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