hw/9pfs/9p-xattr.c

   1 /*
   2  * 9p  xattr callback
   3  *
   4  * Copyright IBM, Corp. 2010
   5  *
   6  * Authors:
   7  * Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
   8  *
   9  * This work is licensed under the terms of the GNU GPL, version 2.  See
  10  * the COPYING file in the top-level directory.
  11  *
  12  */
  13
  14 #include "qemu/osdep.h"
  15 #include "9p.h"
  16 #include "fsdev/file-op-9p.h"
  17 #include "9p-xattr.h"
  18
  19
  20 static XattrOperations *get_xattr_operations(XattrOperations **h,
  21                                              const char *name)
  22 {
  23     XattrOperations *xops;
  24     for (xops = *(h)++; xops != NULL; xops = *(h)++) {
  25         if (!strncmp(name, xops->name, strlen(xops->name))) {
  26             return xops;
  27         }
  28     }
  29     return NULL;
  30 }
  31
  32 ssize_t v9fs_get_xattr(FsContext *ctx, const char *path,
  33                        const char *name, void *value, size_t size)
  34 {
  35     XattrOperations *xops = get_xattr_operations(ctx->xops, name);
  36     if (xops) {
  37         return xops->getxattr(ctx, path, name, value, size);
  38     }
  39     errno = EOPNOTSUPP;
  40     return -1;
  41 }
  42
  43 ssize_t pt_listxattr(FsContext *ctx, const char *path,
  44                      char *name, void *value, size_t size)
  45 {
  46     int name_size = strlen(name) + 1;
  47     if (!value) {
  48         return name_size;
  49     }
  50
  51     if (size < name_size) {
  52         errno = ERANGE;
  53         return -1;
  54     }
  55
  56     /* no need for strncpy: name_size is strlen(name)+1 */
  57     memcpy(value, name, name_size);
  58     return name_size;
  59 }
  60
  61
  62 /*
  63  * Get the list and pass to each layer to find out whether
  64  * to send the data or not
  65  */
  66 ssize_t v9fs_list_xattr(FsContext *ctx, const char *path,
  67                         void *value, size_t vsize)
  68 {
  69     ssize_t size = 0;
  70     char *buffer;
  71     void *ovalue = value;
  72     XattrOperations *xops;
  73     char *orig_value, *orig_value_start;
  74     ssize_t xattr_len, parsed_len = 0, attr_len;
  75
  76     /* Get the actual len */
  77     buffer = rpath(ctx, path);
  78     xattr_len = llistxattr(buffer, value, 0);
  79     if (xattr_len <= 0) {
  80         g_free(buffer);
  81         return xattr_len;
  82     }
  83
  84     /* Now fetch the xattr and find the actual size */
  85     orig_value = g_malloc(xattr_len);
  86     xattr_len = llistxattr(buffer, orig_value, xattr_len);
  87     g_free(buffer);
  88
  89     /* store the orig pointer */
  90     orig_value_start = orig_value;
  91     while (xattr_len > parsed_len) {
  92         xops = get_xattr_operations(ctx->xops, orig_value);
  93         if (!xops) {
  94             goto next_entry;
  95         }
  96
  97         if (!value) {
  98             size += xops->listxattr(ctx, path, orig_value, value, vsize);
  99         } else {
 100             size = xops->listxattr(ctx, path, orig_value, value, vsize);
 101             if (size < 0) {
 102                 goto err_out;
 103             }
 104             value += size;
 105             vsize -= size;
 106         }
 107 next_entry:
 108         /* Got the next entry */
 109         attr_len = strlen(orig_value) + 1;
 110         parsed_len += attr_len;
 111         orig_value += attr_len;
 112     }
 113     if (value) {
 114         size = value - ovalue;
 115     }
 116
 117 err_out:
 118     g_free(orig_value_start);
 119     return size;
 120 }
 121
 122 int v9fs_set_xattr(FsContext *ctx, const char *path, const char *name,
 123                    void *value, size_t size, int flags)
 124 {
 125     XattrOperations *xops = get_xattr_operations(ctx->xops, name);
 126     if (xops) {
 127         return xops->setxattr(ctx, path, name, value, size, flags);
 128     }
 129     errno = EOPNOTSUPP;
 130     return -1;
 131
 132 }
 133
 134 int v9fs_remove_xattr(FsContext *ctx,
 135                       const char *path, const char *name)
 136 {
 137     XattrOperations *xops = get_xattr_operations(ctx->xops, name);
 138     if (xops) {
 139         return xops->removexattr(ctx, path, name);
 140     }
 141     errno = EOPNOTSUPP;
 142     return -1;
 143
 144 }
 145
 146 XattrOperations *mapped_xattr_ops[] = {
 147     &mapped_user_xattr,
 148     &mapped_pacl_xattr,
 149     &mapped_dacl_xattr,
 150     NULL,
 151 };
 152
 153 XattrOperations *passthrough_xattr_ops[] = {
 154     &passthrough_user_xattr,
 155     &passthrough_acl_xattr,
 156     NULL,
 157 };
 158
 159 /* for .user none model should be same as passthrough */
 160 XattrOperations *none_xattr_ops[] = {
 161     &passthrough_user_xattr,
 162     &none_acl_xattr,
 163     NULL,
 164 };