lib/libpuffs/read.c

   1 /* Created (MFS based):
   2  *   February 2010 (Evgeniy Ivanov)
   3  */
   4
   5 #include "fs.h"
   6 #include <stddef.h>
   7 #include <string.h>
   8 #include <stdlib.h>
   9 #include <dirent.h>
  10 #include <minix/com.h>
  11 #include <minix/u64.h>
  12 #include <minix/vfsif.h>
  13 #include <assert.h>
  14 #include <sys/param.h>
  15
  16 #include "puffs.h"
  17 #include "puffs_priv.h"
  18
  19
  20 #define GETDENTS_BUFSIZ  4096
  21 static char getdents_buf[GETDENTS_BUFSIZ];
  22
  23 #define RW_BUFSIZ       (128 << 10)
  24 static char rw_buf[RW_BUFSIZ];
  25
  26
  27 /*===========================================================================*
  28  *                              fs_readwrite                                 *
  29  *===========================================================================*/
  30 int fs_readwrite(void)
  31 {
  32   int r = OK, rw_flag;
  33   cp_grant_id_t gid;
  34   off_t pos;
  35   size_t nrbytes, bytes_left, bytes_done = 0;
  36   struct puffs_node *pn;
  37   struct vattr va;
  38   PUFFS_MAKECRED(pcr, &global_kcred);
  39
  40   if ((pn = puffs_pn_nodewalk(global_pu, 0, &fs_m_in.m_vfs_fs_readwrite.inode)) == NULL) {
  41         lpuffs_debug("walk failed...\n");
  42         return(EINVAL);
  43   }
  44
  45   /* Get the values from the request message */
  46   rw_flag = (fs_m_in.m_type == REQ_READ ? READING : WRITING);
  47   gid = fs_m_in.m_vfs_fs_readwrite.grant;
  48   pos = fs_m_in.m_vfs_fs_readwrite.seek_pos;
  49   nrbytes = bytes_left = fs_m_in.m_vfs_fs_readwrite.nbytes;
  50
  51   if (nrbytes > RW_BUFSIZ)
  52         nrbytes = bytes_left = RW_BUFSIZ;
  53
  54   memset(getdents_buf, '\0', GETDENTS_BUFSIZ);  /* Avoid leaking any data */
  55
  56   if (rw_flag == READING) {
  57         if (global_pu->pu_ops.puffs_node_read == NULL)
  58                 return(EINVAL);
  59
  60         r = global_pu->pu_ops.puffs_node_read(global_pu, pn, (uint8_t *)rw_buf,
  61                                                 pos, &bytes_left, pcr, 0);
  62         if (r) {
  63                 lpuffs_debug("puffs_node_read failed\n");
  64                 return(EINVAL);
  65         }
  66
  67         bytes_done = nrbytes - bytes_left;
  68         if (bytes_done) {
  69                 r = sys_safecopyto(VFS_PROC_NR, gid, (vir_bytes) 0,
  70                                    (vir_bytes) rw_buf, bytes_done);
  71                 update_timens(pn, ATIME, NULL);
  72         }
  73   } else if (rw_flag == WRITING) {
  74         /* At first try to change vattr */
  75         if (global_pu->pu_ops.puffs_node_setattr == NULL)
  76                 return(EINVAL);
  77
  78         puffs_vattr_null(&va);
  79         if ((u_quad_t)(pos + bytes_left) > pn->pn_va.va_size)
  80                 va.va_size = bytes_left + pos;
  81         va.va_ctime = va.va_mtime = clock_timespec();
  82         va.va_atime = pn->pn_va.va_atime;
  83
  84         r = global_pu->pu_ops.puffs_node_setattr(global_pu, pn, &va, pcr);
  85         if (r) return(EINVAL);
  86
  87         r = sys_safecopyfrom(VFS_PROC_NR, gid, (vir_bytes) 0,
  88                              (vir_bytes) rw_buf, nrbytes);
  89         if (r != OK) return(EINVAL);
  90
  91         if (global_pu->pu_ops.puffs_node_write == NULL)
  92                 return(EINVAL);
  93
  94         r = global_pu->pu_ops.puffs_node_write(global_pu, pn, (uint8_t *)rw_buf,
  95                                                 pos, &bytes_left, pcr, 0);
  96         bytes_done = nrbytes - bytes_left;
  97   }
  98
  99   if (r != OK) return(EINVAL);
 100
 101   fs_m_out.m_fs_vfs_readwrite.seek_pos = pos + bytes_done;
 102   fs_m_out.m_fs_vfs_readwrite.nbytes = bytes_done;
 103
 104   return(r);
 105 }
 106
 107
 108 /*===========================================================================*
 109  *                              fs_breadwrite                                *
 110  *===========================================================================*/
 111 int fs_breadwrite(void)
 112 {
 113   /* We do not support breads/writes */
 114   panic("bread write requested, but FS doesn't support it!\n");
 115   return(OK);
 116 }
 117
 118
 119 /*===========================================================================*
 120  *                              fs_getdents                                  *
 121  *===========================================================================*/
 122 int fs_getdents(void)
 123 {
 124   int r;
 125   register struct puffs_node *pn;
 126   ino_t ino;
 127   cp_grant_id_t gid;
 128   size_t size, buf_left;
 129   off_t pos;
 130   struct dirent *dent;
 131   int eofflag = 0;
 132   size_t written;
 133   PUFFS_MAKECRED(pcr, &global_kcred);
 134
 135   ino = fs_m_in.m_vfs_fs_getdents.inode;
 136   gid = fs_m_in.m_vfs_fs_getdents.grant;
 137   size = buf_left = fs_m_in.m_vfs_fs_getdents.mem_size;
 138   pos = fs_m_in.m_vfs_fs_getdents.seek_pos;
 139
 140   if ((pn = puffs_pn_nodewalk(global_pu, 0, &ino)) == NULL) {
 141         lpuffs_debug("walk failed...\n");
 142         return(EINVAL);
 143   }
 144
 145   if (GETDENTS_BUFSIZ < size)
 146           size = buf_left = GETDENTS_BUFSIZ;
 147   memset(getdents_buf, '\0', GETDENTS_BUFSIZ);  /* Avoid leaking any data */
 148
 149   dent = (struct dirent*) getdents_buf;
 150
 151   r = global_pu->pu_ops.puffs_node_readdir(global_pu, pn, dent, &pos,
 152                                                 &buf_left, pcr, &eofflag, 0, 0);
 153   if (r) {
 154         lpuffs_debug("puffs_node_readdir returned error\n");
 155         return(EINVAL);
 156   }
 157
 158   assert(buf_left <= size);
 159   written = size - buf_left;
 160
 161   if (written == 0 && !eofflag) {
 162         lpuffs_debug("The user's buffer is too small\n");
 163         return(EINVAL);
 164   }
 165
 166   if (written) {
 167         r = sys_safecopyto(VFS_PROC_NR, gid, (vir_bytes) 0,
 168                              (vir_bytes) getdents_buf, written);
 169         if (r != OK) return(r);
 170   }
 171
 172   update_timens(pn, ATIME, NULL);
 173
 174   fs_m_out.m_fs_vfs_getdents.nbytes = written;
 175   fs_m_out.m_fs_vfs_getdents.seek_pos = pos;
 176
 177   return(OK);
 178 }