servers/vfs/stadir.c

   1 /* This file contains the code for performing four system calls relating to
   2  * status and directories.
   3  *
   4  * The entry points into this file are
   5  *   do_chdir:  perform the CHDIR system call
   6  *   do_chroot: perform the CHROOT system call
   7  *   do_stat:   perform the STAT system call
   8  *   do_fstat:  perform the FSTAT system call
   9  *   do_fstatfs: perform the FSTATFS system call
  10  *   do_lstat:  perform the LSTAT system call
  11  *
  12  * Changes for VFS:
  13  *   Jul 2006 (Balazs Gerofi)
  14  */
  15
  16 #include "fs.h"
  17 #include <sys/stat.h>
  18 #include <sys/statfs.h>
  19 #include <minix/com.h>
  20 #include <minix/u64.h>
  21 #include <string.h>
  22 #include "file.h"
  23 #include "fproc.h"
  24 #include "param.h"
  25
  26 #include <minix/vfsif.h>
  27 #include "vnode.h"
  28 #include "vmnt.h"
  29
  30 FORWARD _PROTOTYPE( int change, (struct vnode **iip, char *name_ptr, int len));
  31 FORWARD _PROTOTYPE( int change_into, (struct vnode **iip, struct vnode *vp));
  32
  33 /*===========================================================================*
  34  *                              do_fchdir                                    *
  35  *===========================================================================*/
  36 PUBLIC int do_fchdir()
  37 {
  38   /* Change directory on already-opened fd. */
  39   struct filp *rfilp;
  40   int r;
  41
  42   /* Is the file descriptor valid? */
  43   if ( (rfilp = get_filp(m_in.fd)) == NIL_FILP) return(err_code);
  44
  45   /* Is it a dir? */
  46   if ((rfilp->filp_vno->v_mode & I_TYPE) != I_DIRECTORY)
  47       return ENOTDIR;
  48
  49   /* Issue request and handle error */
  50   r = forbidden(rfilp->filp_vno, X_BIT);
  51   if (r != OK) return r;
  52
  53   rfilp->filp_vno->v_ref_count++;       /* change_into expects a reference  */
  54
  55   return change_into(&fp->fp_wd, rfilp->filp_vno);
  56 }
  57
  58 /*===========================================================================*
  59  *                              do_chdir                                     *
  60  *===========================================================================*/
  61 PUBLIC int do_chdir()
  62 {
  63 /* Change directory.  This function is  also called by MM to simulate a chdir
  64  * in order to do EXEC, etc.  It also changes the root directory, the uids and
  65  * gids, and the umask.
  66  */
  67   int r;
  68   register struct fproc *rfp;
  69
  70   if (who_e == PM_PROC_NR) {
  71         int slot;
  72         if(isokendpt(m_in.endpt1, &slot) != OK)
  73                 return EINVAL;
  74         rfp = &fproc[slot];
  75
  76         put_vnode(fp->fp_rd);
  77         dup_vnode(fp->fp_rd = rfp->fp_rd);
  78         put_vnode(fp->fp_wd);
  79         dup_vnode(fp->fp_wd = rfp->fp_wd);
  80
  81         /* MM uses access() to check permissions.  To make this work, pretend
  82          * that the user's real ids are the same as the user's effective ids.
  83          * FS calls other than access() do not use the real ids, so are not
  84          * affected.
  85          */
  86         fp->fp_realuid =
  87         fp->fp_effuid = rfp->fp_effuid;
  88         fp->fp_realgid =
  89         fp->fp_effgid = rfp->fp_effgid;
  90         fp->fp_umask = rfp->fp_umask;
  91         return(OK);
  92   }
  93
  94   /* Perform the chdir(name) system call. */
  95   r = change(&fp->fp_wd, m_in.name, m_in.name_length);
  96   return(r);
  97 }
  98
  99 /*===========================================================================*
 100  *                              do_chroot                                    *
 101  *===========================================================================*/
 102 PUBLIC int do_chroot()
 103 {
 104 /* Perform the chroot(name) system call. */
 105
 106   register int r;
 107
 108   if (!super_user) return(EPERM);       /* only su may chroot() */
 109
 110   r = change(&fp->fp_rd, m_in.name, m_in.name_length);
 111   return(r);
 112 }
 113
 114
 115 /*===========================================================================*
 116  *                              change                                       *
 117  *===========================================================================*/
 118 PRIVATE int change(iip, name_ptr, len)
 119 struct vnode **iip;             /* pointer to the inode pointer for the dir */
 120 char *name_ptr;                 /* pointer to the directory name to change to */
 121 int len;                        /* length of the directory name string */
 122 {
 123 /* Do the actual work for chdir() and chroot(). */
 124   struct vnode *vp;
 125   struct lookup_req lookup_req;
 126   int r;
 127
 128   if (fetch_name(name_ptr, len, M3) != OK) return(err_code);
 129
 130   /* Fill in lookup request fields */
 131   lookup_req.path = user_fullpath;
 132   lookup_req.lastc = NULL;
 133   lookup_req.flags = EAT_PATH;
 134
 135   /* Request lookup */
 136   if ((r = lookup_vp(&lookup_req, &vp)) != OK) return r;
 137
 138   /* Is it a dir? */
 139   if ((vp->v_mode & I_TYPE) != I_DIRECTORY)
 140   {
 141       put_vnode(vp);
 142       return ENOTDIR;
 143   }
 144
 145   /* Access check */
 146   r = forbidden(vp, X_BIT);
 147   if (r != OK) {
 148         put_vnode(vp);
 149         return r;
 150   }
 151
 152   return change_into(iip, vp);
 153 }
 154
 155
 156 /*===========================================================================*
 157  *                              change_into                                  *
 158  *===========================================================================*/
 159 PRIVATE int change_into(iip, vp)
 160 struct vnode **iip;             /* pointer to the inode pointer for the dir */
 161 struct vnode *vp;               /* this is what the inode has to become */
 162 {
 163   /* Everything is OK.  Make the change. */
 164   put_vnode(*iip);              /* release the old directory */
 165   *iip = vp;                    /* acquire the new one */
 166
 167   return(OK);
 168 }
 169
 170
 171 /*===========================================================================*
 172  *                              do_stat                                      *
 173  *===========================================================================*/
 174 PUBLIC int do_stat()
 175 {
 176 /* Perform the stat(name, buf) system call. */
 177   struct node_details res;
 178   struct lookup_req lookup_req;
 179   int r;
 180
 181   if (fetch_name(m_in.name1, m_in.name1_length, M1) != OK) return(err_code);
 182
 183   /* Fill in lookup request fields */
 184   lookup_req.path = user_fullpath;
 185   lookup_req.lastc = NULL;
 186   lookup_req.flags = EAT_PATH;
 187
 188   /* Request lookup */
 189   if ((r = lookup(&lookup_req, &res)) != OK) return r;
 190
 191   /* Issue request */
 192   return req_stat(res.fs_e, res.inode_nr, who_e, m_in.name2, 0);
 193 }
 194
 195
 196
 197 /*===========================================================================*
 198  *                              do_fstat                                     *
 199  *===========================================================================*/
 200 PUBLIC int do_fstat()
 201 {
 202 /* Perform the fstat(fd, buf) system call. */
 203   register struct filp *rfilp;
 204   int pipe_pos = 0;
 205
 206   /* Is the file descriptor valid? */
 207   if ( (rfilp = get_filp(m_in.fd)) == NIL_FILP) {
 208           return(err_code);
 209   }
 210
 211   /* If we read from a pipe, send position too */
 212   pipe_pos= 0;
 213   if (rfilp->filp_vno->v_pipe == I_PIPE) {
 214         if (rfilp->filp_mode & R_BIT)
 215                 if (ex64hi(rfilp->filp_pos) != 0)
 216                 {
 217                         panic(__FILE__, "do_fstat: bad position in pipe",
 218                                 NO_NUM);
 219                 }
 220                 pipe_pos = ex64lo(rfilp->filp_pos);
 221   }
 222
 223   /* Issue request */
 224   return req_stat(rfilp->filp_vno->v_fs_e, rfilp->filp_vno->v_inode_nr,
 225         who_e, m_in.buffer, pipe_pos);
 226 }
 227
 228
 229
 230 /*===========================================================================*
 231  *                              do_fstatfs                                   *
 232  *===========================================================================*/
 233 PUBLIC int do_fstatfs()
 234 {
 235   /* Perform the fstatfs(fd, buf) system call. */
 236   register struct filp *rfilp;
 237
 238   /* Is the file descriptor valid? */
 239   if ( (rfilp = get_filp(m_in.fd)) == NIL_FILP) return(err_code);
 240
 241   /* Issue request */
 242   return req_fstatfs(rfilp->filp_vno->v_fs_e, rfilp->filp_vno->v_inode_nr,
 243         who_e, m_in.buffer);
 244 }
 245
 246
 247
 248 /*===========================================================================*
 249  *                             do_lstat                                      *
 250  *===========================================================================*/
 251 PUBLIC int do_lstat()
 252 {
 253 /* Perform the lstat(name, buf) system call. */
 254   struct node_details res;
 255   struct lookup_req lookup_req;
 256   int r;
 257
 258   if (fetch_name(m_in.name1, m_in.name1_length, M1) != OK) return(err_code);
 259
 260   /* Fill in lookup request fields */
 261   lookup_req.path = user_fullpath;
 262   lookup_req.lastc = NULL;
 263   lookup_req.flags = EAT_PATH_OPAQUE;
 264
 265   /* Request lookup */
 266   if ((r = lookup(&lookup_req, &res)) != OK) return r;
 267
 268   /* Issue request */
 269   return req_stat(res.fs_e, res.inode_nr, who_e, m_in.name2, 0);
 270 }
 271
 272
 273