servers/vfs/time.c

   1 /* This file takes care of those system calls that deal with time.
   2  *
   3  * The entry points into this file are
   4  *   do_utime:          perform the UTIME system call
   5  */
   6
   7 #include "fs.h"
   8 #include <minix/callnr.h>
   9 #include <minix/com.h>
  10 #include "file.h"
  11 #include "fproc.h"
  12 #include "path.h"
  13 #include "param.h"
  14 #include "vnode.h"
  15 #include <minix/vfsif.h>
  16 #include "vmnt.h"
  17
  18 /*===========================================================================*
  19  *                              do_utime                                     *
  20  *===========================================================================*/
  21 int do_utime()
  22 {
  23 /* Perform the utime(name, timep) system call. */
  24   int r;
  25   time_t actime, modtime, newactime, newmodtime;
  26   struct vnode *vp;
  27   struct vmnt *vmp;
  28   char fullpath[PATH_MAX];
  29   struct lookup resolve;
  30   vir_bytes vname;
  31   size_t vname_length, len;
  32
  33   vname = (vir_bytes) job_m_in.utime_file;
  34   vname_length = (size_t) job_m_in.utime_length;
  35   actime = job_m_in.utime_actime;
  36   modtime = job_m_in.utime_modtime;
  37
  38   /* Adjust for case of 'timep' being NULL;
  39    * utime_strlen then holds the actual size: strlen(name)+1 */
  40   len = vname_length;
  41   if (len == 0) len = (size_t) job_m_in.utime_strlen;
  42
  43   lookup_init(&resolve, fullpath, PATH_NOFLAGS, &vmp, &vp);
  44   resolve.l_vmnt_lock = VMNT_WRITE;
  45   resolve.l_vnode_lock = VNODE_READ;
  46
  47   /* Temporarily open the file */
  48   if (fetch_name(vname, len, fullpath) != OK) return(err_code);
  49   if ((vp = eat_path(&resolve, fp)) == NULL) return(err_code);
  50
  51   /* Only the owner of a file or the super user can change its name. */
  52   r = OK;
  53   if (vp->v_uid != fp->fp_effuid && fp->fp_effuid != SU_UID) r = EPERM;
  54   if (vname_length == 0 && r != OK) r = forbidden(fp, vp, W_BIT);
  55   if (read_only(vp) != OK) r = EROFS; /* Not even su can touch if R/O */
  56   if (r == OK) {
  57         /* Issue request */
  58         if (vname_length == 0) {
  59                 newactime = newmodtime = clock_time();
  60         } else {
  61                 newactime = actime;
  62                 newmodtime = modtime;
  63         }
  64         r = req_utime(vp->v_fs_e, vp->v_inode_nr, newactime, newmodtime);
  65   }
  66
  67   unlock_vnode(vp);
  68   unlock_vmnt(vmp);
  69
  70   put_vnode(vp);
  71   return(r);
  72 }