8a8be1b8c3
fix acquire() to cli() *before* incrementing nlock make T_SYSCALL a trap gate, not an interrupt gate sadly, various crashes if you hold down a keyboard key...
598 lines
10 KiB
C
598 lines
10 KiB
C
#include "types.h"
|
|
#include "param.h"
|
|
#include "mmu.h"
|
|
#include "proc.h"
|
|
#include "defs.h"
|
|
#include "x86.h"
|
|
#include "traps.h"
|
|
#include "syscall.h"
|
|
#include "spinlock.h"
|
|
#include "buf.h"
|
|
#include "fs.h"
|
|
#include "fsvar.h"
|
|
#include "elf.h"
|
|
#include "fd.h"
|
|
#include "fcntl.h"
|
|
|
|
/*
|
|
* User code makes a system call with INT T_SYSCALL.
|
|
* System call number in %eax.
|
|
* Arguments on the stack, from the user call to the C
|
|
* library system call function. The saved user %esp points
|
|
* to a saved program counter, and then the first argument.
|
|
*
|
|
* Return value? Error indication? Errno?
|
|
*/
|
|
|
|
/*
|
|
* fetch 32 bits from a user-supplied pointer.
|
|
* returns 0 if addr was OK, -1 if illegal.
|
|
*/
|
|
int
|
|
fetchint(struct proc *p, uint addr, int *ip)
|
|
{
|
|
*ip = 0;
|
|
|
|
if(addr > p->sz - 4)
|
|
return -1;
|
|
*ip = *(int*)(p->mem + addr);
|
|
return 0;
|
|
}
|
|
|
|
// Fetch byte from a user-supplied pointer.
|
|
// Returns 0 on success, -1 if pointer is illegal.
|
|
int
|
|
fetchbyte(struct proc *p, uint addr, char* c)
|
|
{
|
|
if(addr >= p->sz)
|
|
return -1;
|
|
*c = *(p->mem + addr);
|
|
return 0;
|
|
}
|
|
|
|
// This arg is void* so that both int* and uint* can be passed.
|
|
int
|
|
fetcharg(int argno, void *ip)
|
|
{
|
|
uint esp;
|
|
|
|
esp = (uint) curproc[cpu()]->tf->esp;
|
|
return fetchint(curproc[cpu()], esp + 4 + 4*argno, ip);
|
|
}
|
|
|
|
// check that an entire string is valid in user space.
|
|
// returns the length, not including null, or -1.
|
|
int
|
|
checkstring(uint s)
|
|
{
|
|
char c;
|
|
int len = 0;
|
|
|
|
while(1){
|
|
if(fetchbyte(curproc[cpu()], s, &c) < 0)
|
|
return -1;
|
|
if(c == '\0')
|
|
return len;
|
|
len++;
|
|
s++;
|
|
}
|
|
}
|
|
|
|
int
|
|
putint(struct proc *p, uint addr, int x)
|
|
{
|
|
if(addr > p->sz - 4)
|
|
return -1;
|
|
memmove(p->mem + addr, &x, 4);
|
|
return 0;
|
|
}
|
|
|
|
int
|
|
sys_pipe(void)
|
|
{
|
|
struct fd *rfd = 0, *wfd = 0;
|
|
int f1 = -1, f2 = -1;
|
|
struct proc *p = curproc[cpu()];
|
|
uint fdp;
|
|
|
|
if(pipe_alloc(&rfd, &wfd) < 0)
|
|
goto oops;
|
|
if((f1 = fd_ualloc()) < 0)
|
|
goto oops;
|
|
p->fds[f1] = rfd;
|
|
if((f2 = fd_ualloc()) < 0)
|
|
goto oops;
|
|
p->fds[f2] = wfd;
|
|
if(fetcharg(0, &fdp) < 0)
|
|
goto oops;
|
|
if(putint(p, fdp, f1) < 0)
|
|
goto oops;
|
|
if(putint(p, fdp+4, f2) < 0)
|
|
goto oops;
|
|
return 0;
|
|
|
|
oops:
|
|
cprintf("sys_pipe failed\n");
|
|
if(rfd)
|
|
fd_close(rfd);
|
|
if(wfd)
|
|
fd_close(wfd);
|
|
if(f1 >= 0)
|
|
p->fds[f1] = 0;
|
|
if(f2 >= 0)
|
|
p->fds[f2] = 0;
|
|
return -1;
|
|
}
|
|
|
|
int
|
|
sys_write(void)
|
|
{
|
|
int fd, n, ret;
|
|
uint addr;
|
|
struct proc *p = curproc[cpu()];
|
|
|
|
if(fetcharg(0, &fd) < 0 || fetcharg(1, &addr) < 0 || fetcharg(2, &n) < 0)
|
|
return -1;
|
|
if(fd < 0 || fd >= NOFILE)
|
|
return -1;
|
|
if(p->fds[fd] == 0)
|
|
return -1;
|
|
if(addr + n > p->sz)
|
|
return -1;
|
|
ret = fd_write(p->fds[fd], p->mem + addr, n);
|
|
return ret;
|
|
}
|
|
|
|
int
|
|
sys_read(void)
|
|
{
|
|
int fd, n, ret;
|
|
uint addr;
|
|
struct proc *p = curproc[cpu()];
|
|
|
|
if(fetcharg(0, &fd) < 0 || fetcharg(1, &addr) < 0 || fetcharg(2, &n) < 0)
|
|
return -1;
|
|
if(fd < 0 || fd >= NOFILE)
|
|
return -1;
|
|
if(p->fds[fd] == 0)
|
|
return -1;
|
|
if(addr + n > p->sz)
|
|
return -1;
|
|
ret = fd_read(p->fds[fd], p->mem + addr, n);
|
|
return ret;
|
|
}
|
|
|
|
int
|
|
sys_close(void)
|
|
{
|
|
int fd;
|
|
struct proc *p = curproc[cpu()];
|
|
|
|
if(fetcharg(0, &fd) < 0)
|
|
return -1;
|
|
if(fd < 0 || fd >= NOFILE)
|
|
return -1;
|
|
if(p->fds[fd] == 0)
|
|
return -1;
|
|
fd_close(p->fds[fd]);
|
|
p->fds[fd] = 0;
|
|
return 0;
|
|
}
|
|
|
|
int
|
|
sys_fork(void)
|
|
{
|
|
struct proc *np;
|
|
|
|
if((np = copyproc(curproc[cpu()])) == 0)
|
|
return -1;
|
|
np->state = RUNNABLE;
|
|
return np->pid;
|
|
}
|
|
|
|
int
|
|
sys_exit(void)
|
|
{
|
|
proc_exit();
|
|
return 0; // not reached
|
|
}
|
|
|
|
int
|
|
sys_wait(void)
|
|
{
|
|
return proc_wait();
|
|
}
|
|
|
|
int
|
|
sys_kill(void)
|
|
{
|
|
int pid;
|
|
|
|
if(fetcharg(0, &pid) < 0)
|
|
return -1;
|
|
return proc_kill(pid);
|
|
}
|
|
|
|
int
|
|
sys_cons_putc(void)
|
|
{
|
|
int c;
|
|
char buf[2];
|
|
|
|
if(fetcharg(0, &c) < 0)
|
|
return -1;
|
|
buf[0] = c;
|
|
buf[1] = 0;
|
|
cprintf("%s", buf);
|
|
return 0;
|
|
}
|
|
|
|
int
|
|
sys_cons_puts(void)
|
|
{
|
|
char buf[256];
|
|
int i;
|
|
uint addr;
|
|
struct proc *cp = curproc[cpu()];
|
|
|
|
if(fetcharg(0, &addr) < 0)
|
|
return -1;
|
|
for(i=0; i<sizeof buf-1 && fetchbyte(cp, addr+i, &buf[i]) >= 0; i++)
|
|
if(buf[i] == 0)
|
|
break;
|
|
buf[i] = 0;
|
|
cprintf("%s", buf);
|
|
return 0;
|
|
}
|
|
|
|
int
|
|
sys_open(void)
|
|
{
|
|
struct proc *cp = curproc[cpu()];
|
|
struct inode *ip;
|
|
uint arg0, arg1;
|
|
int ufd;
|
|
struct fd *fd;
|
|
struct inode *dp;
|
|
int l;
|
|
|
|
if(fetcharg(0, &arg0) < 0 || fetcharg(1, &arg1) < 0)
|
|
return -1;
|
|
if((l = checkstring(arg0)) < 0)
|
|
return -1;
|
|
if((ip = namei(cp->mem + arg0)) == 0) {
|
|
if (arg1 & O_CREATE) {
|
|
if (l >= DIRSIZ)
|
|
return -1;
|
|
dp = iget(rootdev, 1); // XXX should parse name
|
|
if (dp->type != T_DIR)
|
|
return -1;
|
|
if ((ip = mknod (dp, cp->mem + arg0, T_FILE, 0, 0)) == 0)
|
|
return -1;
|
|
} else return -1;
|
|
}
|
|
if((fd = fd_alloc()) == 0){
|
|
iput(ip);
|
|
return -1;
|
|
}
|
|
if((ufd = fd_ualloc()) < 0){
|
|
iput(ip);
|
|
fd_close(fd);
|
|
return -1;
|
|
}
|
|
|
|
iunlock(ip);
|
|
fd->type = FD_FILE;
|
|
if (arg1 & O_RDWR) {
|
|
fd->readable = 1;
|
|
fd->writeable = 1;
|
|
} else if (arg1 & O_WRONLY) {
|
|
fd->readable = 0;
|
|
fd->writeable = 1;
|
|
} else {
|
|
fd->readable = 1;
|
|
fd->writeable = 0;
|
|
}
|
|
fd->ip = ip;
|
|
fd->off = 0;
|
|
cp->fds[ufd] = fd;
|
|
|
|
return ufd;
|
|
}
|
|
|
|
int
|
|
sys_mknod(void)
|
|
{
|
|
struct proc *cp = curproc[cpu()];
|
|
struct inode *dp, *nip;
|
|
uint arg0, arg1, arg2, arg3;
|
|
int l;
|
|
|
|
if(fetcharg(0, &arg0) < 0 || fetcharg(1, &arg1) < 0 ||
|
|
fetcharg(2, &arg2) < 0 || fetcharg(3, &arg3) < 0)
|
|
return -1;
|
|
|
|
if((l = checkstring(arg0)) < 0)
|
|
return -1;
|
|
|
|
if(l >= DIRSIZ)
|
|
return -1;
|
|
|
|
dp = iget(rootdev, 1); // XXX should parse name
|
|
if (dp->type != T_DIR)
|
|
return -1;
|
|
nip = mknod (dp, cp->mem + arg0, (short) arg1, (short) arg2,
|
|
(short) arg3);
|
|
|
|
if (nip == 0) return -1;
|
|
iput(nip);
|
|
iput(dp);
|
|
|
|
return 0;
|
|
}
|
|
|
|
int
|
|
sys_unlink(void)
|
|
{
|
|
struct proc *cp = curproc[cpu()];
|
|
struct inode *ip;
|
|
uint arg0;
|
|
|
|
if(fetcharg(0, &arg0) < 0)
|
|
return -1;
|
|
|
|
if(checkstring(arg0) < 0)
|
|
return -1;
|
|
|
|
ip = namei(cp->mem + arg0);
|
|
ip->nlink--;
|
|
if (ip->nlink <= 0) {
|
|
panic("sys_link: unimplemented\n");
|
|
}
|
|
iupdate(ip);
|
|
iput(ip);
|
|
|
|
return 0;
|
|
}
|
|
|
|
int
|
|
sys_exec(void)
|
|
{
|
|
struct proc *cp = curproc[cpu()];
|
|
uint arg0, arg1, sz=0, ap, sp, p1, p2;
|
|
int i, nargs, argbytes, len;
|
|
struct inode *ip;
|
|
struct elfhdr elf;
|
|
struct proghdr ph;
|
|
char *mem = 0;
|
|
|
|
if(fetcharg(0, &arg0) < 0)
|
|
return -1;
|
|
if(fetcharg(1, &arg1) < 0)
|
|
return -1;
|
|
if(checkstring(arg0) < 0)
|
|
return -1;
|
|
ip = namei(cp->mem + arg0);
|
|
if(ip == 0)
|
|
return -1;
|
|
|
|
if(readi(ip, &elf, 0, sizeof(elf)) < sizeof(elf))
|
|
goto bad;
|
|
|
|
if(elf.magic != ELF_MAGIC)
|
|
goto bad;
|
|
|
|
sz = 0;
|
|
for(i = 0; i < elf.phnum; i++){
|
|
if(readi(ip, &ph, elf.phoff + i * sizeof(ph), sizeof(ph)) != sizeof(ph))
|
|
goto bad;
|
|
if(ph.type != ELF_PROG_LOAD)
|
|
continue;
|
|
if(ph.memsz < ph.filesz)
|
|
goto bad;
|
|
sz += ph.memsz;
|
|
}
|
|
|
|
sz += 4096 - (sz % 4096);
|
|
sz += 4096;
|
|
|
|
mem = kalloc(sz);
|
|
if(mem == 0)
|
|
goto bad;
|
|
memset(mem, 0, sz);
|
|
|
|
// arg1 is a pointer to an array of pointers to string.
|
|
nargs = 0;
|
|
argbytes = 0;
|
|
for(i = 0; ; i++){
|
|
if(fetchint(cp, arg1 + 4*i, &ap) < 0)
|
|
goto bad;
|
|
if(ap == 0)
|
|
break;
|
|
len = checkstring(ap);
|
|
if(len < 0)
|
|
goto bad;
|
|
nargs++;
|
|
argbytes += len + 1;
|
|
}
|
|
|
|
// argn\0
|
|
// ...
|
|
// arg0\0
|
|
// 0
|
|
// ptr to argn
|
|
// ...
|
|
// 12: ptr to arg0
|
|
// 8: argv (points to ptr to arg0)
|
|
// 4: argc
|
|
// 0: fake return pc
|
|
sp = sz - argbytes - (nargs+1)*4 - 4 - 4 - 4;
|
|
*(uint*)(mem + sp) = 0xffffffff;
|
|
*(uint*)(mem + sp + 4) = nargs;
|
|
*(uint*)(mem + sp + 8) = (uint)(sp + 12);
|
|
|
|
p1 = sp + 12;
|
|
p2 = sp + 12 + (nargs + 1) * 4;
|
|
for(i = 0; i < nargs; i++){
|
|
fetchint(cp, arg1 + 4*i, &ap);
|
|
len = checkstring(ap);
|
|
memmove(mem + p2, cp->mem + ap, len + 1);
|
|
*(uint*)(mem + p1) = p2;
|
|
p1 += 4;
|
|
p2 += len + 1;
|
|
}
|
|
*(uint*)(mem + p1) = 0;
|
|
|
|
// commit to the new image.
|
|
kfree(cp->mem, cp->sz);
|
|
cp->sz = sz;
|
|
cp->mem = mem;
|
|
mem = 0;
|
|
|
|
for(i = 0; i < elf.phnum; i++){
|
|
if(readi(ip, &ph, elf.phoff + i * sizeof(ph), sizeof(ph)) != sizeof(ph))
|
|
goto bad2;
|
|
if(ph.type != ELF_PROG_LOAD)
|
|
continue;
|
|
if(ph.va + ph.memsz > sz)
|
|
goto bad2;
|
|
if(readi(ip, cp->mem + ph.va, ph.offset, ph.filesz) != ph.filesz)
|
|
goto bad2;
|
|
memset(cp->mem + ph.va + ph.filesz, 0, ph.memsz - ph.filesz);
|
|
}
|
|
|
|
iput(ip);
|
|
|
|
cp->tf->eip = elf.entry;
|
|
cp->tf->esp = sp;
|
|
setupsegs(cp);
|
|
|
|
return 0;
|
|
|
|
bad:
|
|
cprintf("exec failed early\n");
|
|
if(mem)
|
|
kfree(mem, sz);
|
|
iput(ip);
|
|
return -1;
|
|
|
|
bad2:
|
|
cprintf("exec failed late\n");
|
|
iput(ip);
|
|
proc_exit();
|
|
return 0;
|
|
}
|
|
|
|
int
|
|
sys_block(void)
|
|
{
|
|
int i, j;
|
|
struct buf *b;
|
|
struct inode *ip;
|
|
|
|
for (i = 0; i < 2; i++) {
|
|
cprintf ("issue read\n");
|
|
b = bread(1, i);
|
|
|
|
cprintf("disk 1 sector %d: ", i);
|
|
for (j = 0; j < 4; j++)
|
|
cprintf("%x ", b->data[j] & 0xff);
|
|
cprintf("\n");
|
|
|
|
brelse(b);
|
|
}
|
|
|
|
ip = iget(1, 1);
|
|
cprintf("iget 1: %d %d %d %d %d %d %d %d\n",
|
|
ip->dev, ip->inum, ip->count, ip->busy,
|
|
ip->type, ip->nlink, ip->size, ip->addrs[0]);
|
|
iput(ip);
|
|
|
|
ip = namei(".././//./../usertests");
|
|
if(ip){
|
|
cprintf("namei(usertests): %d %d %d %d %d %d %d %d\n",
|
|
ip->dev, ip->inum, ip->count, ip->busy,
|
|
ip->type, ip->nlink, ip->size, ip->addrs[0]);
|
|
iput(ip);
|
|
} else {
|
|
cprintf("namei(usertests) failed\n");
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
int
|
|
sys_panic(void)
|
|
{
|
|
struct proc *p = curproc[cpu()];
|
|
uint addr;
|
|
|
|
if(fetcharg(0, &addr) < 0)
|
|
return -1;
|
|
panic(p->mem + addr);
|
|
return 0;
|
|
}
|
|
|
|
void
|
|
syscall(void)
|
|
{
|
|
struct proc *cp = curproc[cpu()];
|
|
int num = cp->tf->eax;
|
|
int ret = -1;
|
|
|
|
switch(num){
|
|
case SYS_fork:
|
|
ret = sys_fork();
|
|
break;
|
|
case SYS_exit:
|
|
ret = sys_exit();
|
|
break;
|
|
case SYS_wait:
|
|
ret = sys_wait();
|
|
break;
|
|
case SYS_cons_putc:
|
|
ret = sys_cons_putc();
|
|
break;
|
|
case SYS_pipe:
|
|
ret = sys_pipe();
|
|
break;
|
|
case SYS_write:
|
|
ret = sys_write();
|
|
break;
|
|
case SYS_read:
|
|
ret = sys_read();
|
|
break;
|
|
case SYS_close:
|
|
ret = sys_close();
|
|
break;
|
|
case SYS_block:
|
|
ret = sys_block();
|
|
break;
|
|
case SYS_kill:
|
|
ret = sys_kill();
|
|
break;
|
|
case SYS_panic:
|
|
ret = sys_panic();
|
|
break;
|
|
case SYS_cons_puts:
|
|
ret = sys_cons_puts();
|
|
break;
|
|
case SYS_exec:
|
|
ret = sys_exec();
|
|
break;
|
|
case SYS_open:
|
|
ret = sys_open();
|
|
break;
|
|
case SYS_mknod:
|
|
ret = sys_mknod();
|
|
break;
|
|
case SYS_unlink:
|
|
ret = sys_unlink();
|
|
break;
|
|
default:
|
|
cprintf("unknown sys call %d\n", num);
|
|
// XXX fault
|
|
break;
|
|
}
|
|
cp->tf->eax = ret;
|
|
}
|