/*
* Changes working directory.
*/
PUBLIC int sys_chroot(const char *path)
{
struct inode *inode;
inode = inode_name(path);
/* Failed to get inode. */
if (inode == NULL)
return (curr_proc->errno);
/* Not a directory. */
if (!S_ISDIR(inode->mode))
{
inode_put(inode);
return (-ENOTDIR);
}
inode_put(curr_proc->root);
curr_proc->root = inode;
inode_unlock(inode);
return (0);
}
/*
* Executes a program.
*/
PUBLIC int sys_execve(const char *filename, const char **argv, const char **envp)
{
int i; /* Loop index. */
struct inode *inode; /* File inode. */
struct region *reg; /* Process region. */
addr_t entry; /* Program entry point. */
addr_t sp; /* User stack pointer. */
char *name; /* File name. */
char stack[ARG_MAX]; /* Stack size. */
/* Get file name. */
if ((name = getname(filename)) == NULL)
return (curr_proc->errno);
/* Build arguments before freeing user memory. */
kmemset(stack, 0, ARG_MAX);
if (!(sp = buildargs(stack, ARG_MAX, argv, envp)))
{
putname(name);
return (curr_proc->errno);
}
/* Get file's inode. */
if ((inode = inode_name(name)) == NULL)
{
putname(name);
return (curr_proc->errno);
}
/* Not a regular file. */
if (!S_ISREG(inode->mode))
{
putname(name);
inode_put(inode);
return (-EACCES);
}
/* Not allowed. */
if (!permission(inode->mode, inode->uid, inode->gid, curr_proc, MAY_EXEC, 0))
{
putname(name);
inode_put(inode);
return (-EACCES);
}
/* Close file descriptors. */
for (i = 0; i < OPEN_MAX; i++)
{
if (curr_proc->close & (1 << i))
do_close(i);
}
/* Detach process memory regions. */
for (i = 0; i < NR_PREGIONS; i++)
detachreg(curr_proc, &curr_proc->pregs[i]);
/* Reset signal handlers. */
curr_proc->restorer = NULL;
for (i = 0; i < NR_SIGNALS; i++)
{
if (curr_proc->handlers[i] != SIG_DFL)
{
if (curr_proc->handlers[i] != SIG_IGN)
curr_proc->handlers[i] = SIG_DFL;
}
}
/* Load executable. */
if (!(entry = load_elf32(inode)))
goto die0;
/* Attach stack region. */
if ((reg = allocreg(S_IRUSR | S_IWUSR, PAGE_SIZE, REGION_DOWNWARDS)) == NULL)
goto die0;
if (attachreg(curr_proc, STACK(curr_proc), USTACK_ADDR - 1, reg))
goto die1;
unlockreg(reg);
/* Attach heap region. */
if ((reg = allocreg(S_IRUSR | S_IWUSR, PAGE_SIZE, REGION_UPWARDS)) == NULL)
goto die0;
if (attachreg(curr_proc, HEAP(curr_proc), UHEAP_ADDR, reg))
goto die1;
unlockreg(reg);
inode_put(inode);
putname(name);
kmemcpy((void *)(USTACK_ADDR - ARG_MAX), stack, ARG_MAX);
user_mode(entry, sp);
/* Will not return. */
return (0);
die1:
unlockreg(reg);
freereg(reg);
die0:
inode_put(inode);
putname(name);
die(((SIGSEGV & 0xff) << 16) | (1 << 9));
return (-1);
}
