minix/servers/vfs/stadir.c
Ben Gras cef94e096e vfs: make m_out non-global
m_out is shared between threads as the reply message, and it can happen
results get overwritten by another thread before the reply is sent. This
change

	. makes m_out local to the message handling function,
	  declared on the stack of the caller
	. forces callers of reply() to give it a message, or
	  declare the reply message has no significant fields except
	  for the return code by calling replycode()

Change-Id: Id06300083a63c72c00f34f86a5c7d96e4bbdf9f6
2013-04-12 23:40:38 +00:00

322 lines
8.9 KiB
C

/* This file contains the code for performing four system calls relating to
* status and directories.
*
* The entry points into this file are
* do_chdir: perform the CHDIR system call
* do_chroot: perform the CHROOT system call
* do_lstat: perform the LSTAT system call
* do_stat: perform the STAT system call
* do_fstat: perform the FSTAT system call
* do_fstatfs: perform the FSTATFS system call
* do_statvfs: perform the STATVFS system call
* do_fstatvfs: perform the FSTATVFS system call
*/
#include "fs.h"
#include <sys/stat.h>
#include <sys/statfs.h>
#include <minix/com.h>
#include <minix/u64.h>
#include <string.h>
#include "file.h"
#include "fproc.h"
#include "path.h"
#include "param.h"
#include <minix/vfsif.h>
#include <minix/callnr.h>
#include "vnode.h"
#include "vmnt.h"
static int change_into(struct vnode **iip, struct vnode *vp);
/*===========================================================================*
* do_fchdir *
*===========================================================================*/
int do_fchdir(message *UNUSED(m_out))
{
/* Change directory on already-opened fd. */
struct filp *rfilp;
int r, rfd;
rfd = job_m_in.fd;
/* Is the file descriptor valid? */
if ((rfilp = get_filp(rfd, VNODE_READ)) == NULL) return(err_code);
r = change_into(&fp->fp_wd, rfilp->filp_vno);
unlock_filp(rfilp);
return(r);
}
/*===========================================================================*
* do_chdir *
*===========================================================================*/
int do_chdir(message *UNUSED(m_out))
{
/* Perform the chdir(name) system call.
* syscall might provide 'name' embedded in the message.
*/
int r;
struct vnode *vp;
struct vmnt *vmp;
char fullpath[PATH_MAX];
struct lookup resolve;
vir_bytes vname;
size_t vname_length;
vname = (vir_bytes) job_m_in.name;
vname_length = (size_t) job_m_in.name_length;
if (copy_name(vname_length, fullpath) != OK) {
/* Direct copy failed, try fetching from user space */
if (fetch_name(vname, vname_length, fullpath) != OK)
return(err_code);
}
/* Try to open the directory */
lookup_init(&resolve, fullpath, PATH_NOFLAGS, &vmp, &vp);
resolve.l_vmnt_lock = VMNT_READ;
resolve.l_vnode_lock = VNODE_READ;
if ((vp = eat_path(&resolve, fp)) == NULL) return(err_code);
r = change_into(&fp->fp_wd, vp);
unlock_vnode(vp);
unlock_vmnt(vmp);
put_vnode(vp);
return(r);
}
/*===========================================================================*
* do_chroot *
*===========================================================================*/
int do_chroot(message *UNUSED(m_out))
{
/* Perform the chroot(name) system call.
* syscall might provide 'name' embedded in the message.
*/
int r;
struct vnode *vp;
struct vmnt *vmp;
char fullpath[PATH_MAX];
struct lookup resolve;
vir_bytes vname;
size_t vname_length;
vname = (vir_bytes) job_m_in.name;
vname_length = (size_t) job_m_in.name_length;
if (!super_user) return(EPERM); /* only su may chroot() */
if (copy_name(vname_length, fullpath) != OK) {
/* Direct copy failed, try fetching from user space */
if (fetch_name(vname, vname_length, fullpath) != OK)
return(err_code);
}
/* Try to open the directory */
lookup_init(&resolve, fullpath, PATH_NOFLAGS, &vmp, &vp);
resolve.l_vmnt_lock = VMNT_READ;
resolve.l_vnode_lock = VNODE_READ;
if ((vp = eat_path(&resolve, fp)) == NULL) return(err_code);
r = change_into(&fp->fp_rd, vp);
unlock_vnode(vp);
unlock_vmnt(vmp);
put_vnode(vp);
return(r);
}
/*===========================================================================*
* change_into *
*===========================================================================*/
static int change_into(struct vnode **result, struct vnode *vp)
{
int r;
if (*result == vp) return(OK); /* Nothing to do */
/* It must be a directory and also be searchable */
if (!S_ISDIR(vp->v_mode))
r = ENOTDIR;
else
r = forbidden(fp, vp, X_BIT); /* Check if dir is searchable*/
if (r != OK) return(r);
/* Everything is OK. Make the change. */
put_vnode(*result); /* release the old directory */
dup_vnode(vp);
*result = vp; /* acquire the new one */
return(OK);
}
/*===========================================================================*
* do_stat *
*===========================================================================*/
int do_stat(message *UNUSED(m_out))
{
/* Perform the stat(name, buf) system call. */
int r;
struct vnode *vp;
struct vmnt *vmp;
char fullpath[PATH_MAX];
struct lookup resolve;
vir_bytes vname1, statbuf;
size_t vname1_length;
vname1 = (vir_bytes) job_m_in.name1;
vname1_length = (size_t) job_m_in.name1_length;
statbuf = (vir_bytes) job_m_in.m1_p2;
lookup_init(&resolve, fullpath, PATH_NOFLAGS, &vmp, &vp);
resolve.l_vmnt_lock = VMNT_READ;
resolve.l_vnode_lock = VNODE_READ;
if (fetch_name(vname1, vname1_length, fullpath) != OK) return(err_code);
if ((vp = eat_path(&resolve, fp)) == NULL) return(err_code);
r = req_stat(vp->v_fs_e, vp->v_inode_nr, who_e, statbuf);
unlock_vnode(vp);
unlock_vmnt(vmp);
put_vnode(vp);
return r;
}
/*===========================================================================*
* do_fstat *
*===========================================================================*/
int do_fstat(message *UNUSED(m_out))
{
/* Perform the fstat(fd, buf) system call. */
register struct filp *rfilp;
int r, rfd;
vir_bytes statbuf;
statbuf = (vir_bytes) job_m_in.buffer;
rfd = job_m_in.fd;
/* Is the file descriptor valid? */
if ((rfilp = get_filp(rfd, VNODE_READ)) == NULL) return(err_code);
r = req_stat(rfilp->filp_vno->v_fs_e, rfilp->filp_vno->v_inode_nr,
who_e, statbuf);
unlock_filp(rfilp);
return(r);
}
/*===========================================================================*
* do_fstatfs *
*===========================================================================*/
int do_fstatfs(message *UNUSED(m_out))
{
/* Perform the fstatfs(fd, buf) system call. */
struct filp *rfilp;
int r, rfd;
vir_bytes statbuf;
rfd = job_m_in.fd;
statbuf = (vir_bytes) job_m_in.buffer;
/* Is the file descriptor valid? */
if( (rfilp = get_filp(rfd, VNODE_READ)) == NULL) return(err_code);
r = req_fstatfs(rfilp->filp_vno->v_fs_e, who_e, statbuf);
unlock_filp(rfilp);
return(r);
}
/*===========================================================================*
* do_statvfs *
*===========================================================================*/
int do_statvfs(message *UNUSED(m_out))
{
/* Perform the stat(name, buf) system call. */
int r;
struct vnode *vp;
struct vmnt *vmp;
char fullpath[PATH_MAX];
struct lookup resolve;
vir_bytes vname1, statbuf;
size_t vname1_length;
vname1 = (vir_bytes) job_m_in.name1;
vname1_length = (size_t) job_m_in.name1_length;
statbuf = (vir_bytes) job_m_in.name2;
lookup_init(&resolve, fullpath, PATH_NOFLAGS, &vmp, &vp);
resolve.l_vmnt_lock = VMNT_READ;
resolve.l_vnode_lock = VNODE_READ;
if (fetch_name(vname1, vname1_length, fullpath) != OK) return(err_code);
if ((vp = eat_path(&resolve, fp)) == NULL) return(err_code);
r = req_statvfs(vp->v_fs_e, who_e, statbuf);
unlock_vnode(vp);
unlock_vmnt(vmp);
put_vnode(vp);
return r;
}
/*===========================================================================*
* do_fstatvfs *
*===========================================================================*/
int do_fstatvfs(message *UNUSED(m_out))
{
/* Perform the fstat(fd, buf) system call. */
register struct filp *rfilp;
int r, rfd;
vir_bytes statbuf;
rfd = job_m_in.fd;
statbuf = (vir_bytes) job_m_in.name2;
/* Is the file descriptor valid? */
if ((rfilp = get_filp(rfd, VNODE_READ)) == NULL) return(err_code);
r = req_statvfs(rfilp->filp_vno->v_fs_e, who_e, statbuf);
unlock_filp(rfilp);
return(r);
}
/*===========================================================================*
* do_lstat *
*===========================================================================*/
int do_lstat(message *UNUSED(m_out))
{
/* Perform the lstat(name, buf) system call. */
struct vnode *vp;
struct vmnt *vmp;
int r;
char fullpath[PATH_MAX];
struct lookup resolve;
vir_bytes vname1, statbuf;
size_t vname1_length;
vname1 = (vir_bytes) job_m_in.name1;
vname1_length = (size_t) job_m_in.name1_length;
statbuf = (vir_bytes) job_m_in.name2;
lookup_init(&resolve, fullpath, PATH_RET_SYMLINK, &vmp, &vp);
resolve.l_vmnt_lock = VMNT_READ;
resolve.l_vnode_lock = VNODE_READ;
if (fetch_name(vname1, vname1_length, fullpath) != OK) return(err_code);
if ((vp = eat_path(&resolve, fp)) == NULL) return(err_code);
r = req_stat(vp->v_fs_e, vp->v_inode_nr, who_e, statbuf);
unlock_vnode(vp);
unlock_vmnt(vmp);
put_vnode(vp);
return(r);
}