static int redirect_file_access(struct tracy_event *e, int argpos,
bool resolve_symlinks)
{
struct tracy_sc_args a;
int rc = TRACY_HOOK_CONTINUE;
char *path = NULL;
tracy_child_addr_t devname_new = NULL;
struct fstab_rec *fstabrec;
long *argptr;
struct multiboot_child_data *mbc = e->child->custom;
// call hook_open
if (e->syscall_num == get_syscall_number_abi("open", e->abi)
|| e->syscall_num == get_syscall_number_abi("openat", e->abi)) {
int rc_open = hook_open(e, argpos, resolve_symlinks);
if (rc_open)
return rc_open;
}
if (e->child->pre_syscall) {
// get path
argptr = &e->args.a0;
path = get_patharg(e->child, argptr[argpos], resolve_symlinks);
if (!path) {
rc = TRACY_HOOK_ABORT;
goto out;
}
// check if we need to redirect this file
fstabrec = get_fstab_rec(path);
if (!fstabrec) {
goto out;
}
// ignore symlinks for calls which don't resolve them
struct stat sb;
if (!resolve_symlinks && !lstat(path, &sb)
&& S_ISLNK(sb.st_mode)) {
goto out;
}
char *replacement =
fstabrec->replacement_bind ? fstabrec->
stub_device : fstabrec->replacement_device;
DEBUG("%s(%s): redirect %s->%s arg=%d\n", __func__,
get_syscall_name_abi(e->syscall_num, e->abi), path,
replacement, argpos);
// copy new devname
devname_new = copy_patharg(e->child, replacement);
if (!devname_new) {
kperror("copy_patharg");
rc = TRACY_HOOK_ABORT;
goto out;
}
// copy args
memcpy(&a, &(e->args), sizeof(struct tracy_sc_args));
// modify args
argptr = &a.a0;
argptr[argpos] = (long)devname_new;
// write new args
if (tracy_modify_syscall_args(e->child, a.syscall, &a)) {
kperror("tracy_modify_syscall_args");
rc = TRACY_HOOK_ABORT;
goto out;
}
// set devname so we can free it later
mbc->memory = devname_new;
} else {
// free previous data
if (mbc->memory) {
free_patharg(e->child, mbc->memory);
mbc->memory = NULL;
}
}
out:
if (path)
free(path);
if (devname_new && rc)
free_patharg(e->child, devname_new);
return rc;
}
static int hook_mount(struct tracy_event *e)
{
struct tracy_sc_args a;
struct fstab_rec *fstabrec;
tracy_child_addr_t devname_new = NULL;
char *devname = NULL, *mountpoint = NULL;
int rc = TRACY_HOOK_CONTINUE;
struct multiboot_child_data *mbc = e->child->custom;
if (e->child->pre_syscall) {
// get args
devname = get_patharg(e->child, e->args.a0, 1);
if (!devname) {
rc = TRACY_HOOK_ABORT;
goto out;
}
mountpoint = get_patharg(e->child, e->args.a1, 1);
if (!mountpoint) {
rc = TRACY_HOOK_ABORT;
goto out;
}
unsigned long flags = (unsigned long)e->args.a3;
DEBUG("mount %s on %s remount=%lu, ro=%lu\n",
devname, mountpoint, (flags & MS_REMOUNT),
(flags & MS_RDONLY));
if (!strcmp(mountpoint, "/mnt/secure/asec")) {
fstabrec = asec_rec;
} else {
// check if we need to redirect this partition
fstabrec = get_fstab_rec(devname);
if (!fstabrec) {
goto out;
}
}
DEBUG("hijack: mount %s on %s\n", devname, mountpoint);
// copy new devname
devname_new =
copy_patharg(e->child, fstabrec->replacement_device);
if (!devname_new) {
kperror("copy_patharg");
rc = TRACY_HOOK_ABORT;
goto out;
}
// copy args
memcpy(&a, &(e->args), sizeof(struct tracy_sc_args));
// modify args
a.a0 = (long)devname_new;
if (fstabrec->replacement_bind) {
a.a2 = 0;
a.a3 |= MS_BIND;
}
// write new args
if (tracy_modify_syscall_args(e->child, a.syscall, &a)) {
kperror("tracy_modify_syscall_args");
rc = TRACY_HOOK_ABORT;
goto out;
}
// set devname so we can free it later
mbc->memory = devname_new;
} else {
// free previous data
if (mbc->memory) {
free_patharg(e->child, mbc->memory);
mbc->memory = NULL;
}
}
out:
if (devname)
free(devname);
if (mountpoint)
free(mountpoint);
if (devname_new && rc)
free_patharg(e->child, devname_new);
return rc;
}
/**
* Call by the exeption to handle the syscall
* \private
*/
void
syscall_handler(registers_t * regs)
{
int32_t res = 0;
int32_t syscall = regs->v_reg[0]; // code of the syscall
switch (syscall)
{
case FOURCHETTE:
res =
create_proc(get_arg((char **) regs->a_reg[2], 0), regs->a_reg[0],
regs->a_reg[1], (char **) regs->a_reg[2]);
break;
case PRINT:
res = print_string((char *) regs->a_reg[0]);
return; /* We save the good return value in the pcb */
case READ:
res = read_string((char *) regs->a_reg[0], regs->a_reg[1]);
return; /* We save the good return value in the pcb */
case FPRINT:
if (regs->a_reg[0] == CONSOLE)
kprint((char *) regs->a_reg[1]);
else
kmaltaprint8((char *) regs->a_reg[1]);
break;
case SLEEP:
res = go_to_sleep(regs->a_reg[0]);
break;
case BLOCK:
res = kblock(regs->a_reg[0], BLOCKED);
break;
case UNBLOCK:
kwakeup(regs->a_reg[0]);
break;
case WAIT:
res = waitfor(regs->a_reg[0], (int32_t *) regs->a_reg[1]);
break;
case SEND:
res =
send_msg(pcb_get_pid(get_current_pcb()), (msg_arg *) regs->a_reg[0]);
break;
case RECV:
res =
recv_msg(pcb_get_pid(get_current_pcb()), (msg_arg *) regs->a_reg[0]);
if (res == NOTFOUND)
go_to_sleep(((msg_arg *) regs->a_reg[0])->timeout);
break;
case PERROR:
kperror((char *) regs->a_reg[0]);
break;
case GERROR:
res = kgerror();
break;
case SERROR:
kserror(regs->a_reg[0]);
break;
case GETPINFO:
res = get_pinfo(regs->a_reg[0], (pcbinfo *) regs->a_reg[1]);
break;
case GETPID:
res = pcb_get_pid(get_current_pcb());
break;
case GETALLPID:
res = get_all_pid((int *) regs->a_reg[0]);
break;
case CHGPPRI:
res = chg_ppri(regs->a_reg[0], regs->a_reg[1]);
break;
case KILL:
res = kkill(regs->a_reg[0]);
break;
case EXIT:
kexit(regs->a_reg[0]);
break;
default:
kprintln("ERROR: Unknown syscall");
break;
}
// saves the return code
regs->v_reg[0] = res;
return;
}
