minix/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 <dirent.h>
   8 #include <sys/param.h>
   9
  10
  11 #define GETDENTS_BUFSIZ  4096
  12 static char getdents_buf[GETDENTS_BUFSIZ];
  13
  14 #define RW_BUFSIZ       (128 * 1024)
  15 static char rw_buf[RW_BUFSIZ];
  16
  17
  18 /*===========================================================================*
  19  *                              fs_read                                      *
  20  *===========================================================================*/
  21 ssize_t fs_read(ino_t ino_nr, struct fsdriver_data *data, size_t bytes,
  22         off_t pos, int call)
  23 {
  24   int r;
  25   size_t bytes_left, bytes_done;
  26   struct puffs_node *pn;
  27   PUFFS_MAKECRED(pcr, &global_kcred);
  28
  29   if ((pn = puffs_pn_nodewalk(global_pu, find_inode_cb, &ino_nr)) == NULL) {
  30         lpuffs_debug("walk failed...\n");
  31         return(EINVAL);
  32   }
  33
  34   if (bytes > sizeof(rw_buf))
  35         bytes = sizeof(rw_buf);
  36   bytes_left = bytes;
  37
  38   if (global_pu->pu_ops.puffs_node_read == NULL)
  39         return(EINVAL);
  40
  41   r = global_pu->pu_ops.puffs_node_read(global_pu, pn, (uint8_t *)rw_buf,
  42                                                 pos, &bytes_left, pcr, 0);
  43   if (r) {
  44         lpuffs_debug("puffs_node_read failed\n");
  45         return(EINVAL);
  46   }
  47
  48   bytes_done = bytes - bytes_left;
  49
  50   if (bytes_done > 0) {
  51         if ((r = fsdriver_copyout(data, 0, rw_buf, bytes_done)) != OK)
  52                 return r;
  53         update_timens(pn, ATIME, NULL);
  54   }
  55
  56   return (ssize_t)bytes_done;
  57 }
  58
  59
  60 /*===========================================================================*
  61  *                              fs_write                                     *
  62  *===========================================================================*/
  63 ssize_t fs_write(ino_t ino_nr, struct fsdriver_data *data, size_t bytes,
  64         off_t pos, int call)
  65 {
  66   int r;
  67   size_t bytes_left;
  68   struct puffs_node *pn;
  69   struct vattr va;
  70   struct timespec cur_time;
  71   PUFFS_MAKECRED(pcr, &global_kcred);
  72
  73   if ((pn = puffs_pn_nodewalk(global_pu, find_inode_cb, &ino_nr)) == NULL) {
  74         lpuffs_debug("walk failed...\n");
  75         return(EINVAL);
  76   }
  77
  78   if (bytes > sizeof(rw_buf))
  79         bytes = sizeof(rw_buf);
  80   bytes_left = bytes;
  81
  82   /* At first try to change vattr */
  83   if (global_pu->pu_ops.puffs_node_setattr == NULL)
  84         return(EINVAL);
  85
  86   (void)clock_time(&cur_time);
  87
  88   puffs_vattr_null(&va);
  89   if ((u_quad_t)(pos + bytes_left) > pn->pn_va.va_size)
  90         va.va_size = bytes_left + pos;
  91   va.va_ctime = va.va_mtime = cur_time;
  92   va.va_atime = pn->pn_va.va_atime;
  93
  94   r = global_pu->pu_ops.puffs_node_setattr(global_pu, pn, &va, pcr);
  95   if (r) return(EINVAL);
  96
  97   if ((r = fsdriver_copyin(data, 0, rw_buf, bytes)) != OK)
  98         return r;
  99
 100   if (global_pu->pu_ops.puffs_node_write == NULL)
 101         return(EINVAL);
 102
 103   r = global_pu->pu_ops.puffs_node_write(global_pu, pn, (uint8_t *)rw_buf,
 104                                                 pos, &bytes_left, pcr, 0);
 105   if (r != OK) return(EINVAL);
 106
 107   return (ssize_t)(bytes - bytes_left);
 108 }
 109
 110
 111 /*===========================================================================*
 112  *                              fs_getdents                                  *
 113  *===========================================================================*/
 114 ssize_t fs_getdents(ino_t ino_nr, struct fsdriver_data *data, size_t bytes,
 115         off_t *pos)
 116 {
 117   int r;
 118   register struct puffs_node *pn;
 119   size_t buf_left, written;
 120   struct dirent *dent;
 121   int eofflag = 0;
 122   PUFFS_MAKECRED(pcr, &global_kcred);
 123
 124   if ((pn = puffs_pn_nodewalk(global_pu, find_inode_cb, &ino_nr)) == NULL) {
 125         lpuffs_debug("walk failed...\n");
 126         return(EINVAL);
 127   }
 128
 129   if (bytes > sizeof(getdents_buf))
 130           bytes = sizeof(getdents_buf);
 131   memset(getdents_buf, 0, sizeof(getdents_buf)); /* Avoid leaking any data */
 132
 133   buf_left = bytes;
 134
 135   dent = (struct dirent*) getdents_buf;
 136
 137   r = global_pu->pu_ops.puffs_node_readdir(global_pu, pn, dent, pos,
 138                                                 &buf_left, pcr, &eofflag, 0, 0);
 139   if (r) {
 140         lpuffs_debug("puffs_node_readdir returned error\n");
 141         return(EINVAL);
 142   }
 143
 144   assert(buf_left <= bytes);
 145   written = bytes - buf_left;
 146
 147   if (written == 0 && !eofflag) {
 148         lpuffs_debug("The user's buffer is too small\n");
 149         return(EINVAL);
 150   }
 151
 152   if (written) {
 153         if ((r = fsdriver_copyout(data, 0, getdents_buf, written)) != OK)
 154                 return r;
 155   }
 156
 157   update_timens(pn, ATIME, NULL);
 158
 159   /* The puffs readdir call has already updated the position. */
 160   return written;
 161 }