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  1. /*
  2.  * Copyright (c) 2008 Jakub Jermar
  3.  * All rights reserved.
  4.  *
  5.  * Redistribution and use in source and binary forms, with or without
  6.  * modification, are permitted provided that the following conditions
  7.  * are met:
  8.  *
  9.  * - Redistributions of source code must retain the above copyright
  10.  *   notice, this list of conditions and the following disclaimer.
  11.  * - Redistributions in binary form must reproduce the above copyright
  12.  *   notice, this list of conditions and the following disclaimer in the
  13.  *   documentation and/or other materials provided with the distribution.
  14.  * - The name of the author may not be used to endorse or promote products
  15.  *   derived from this software without specific prior written permission.
  16.  *
  17.  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  18.  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  19.  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  20.  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  21.  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  22.  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  23.  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  24.  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  25.  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  26.  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  27.  */
  28.  
  29. /** @addtogroup libfs
  30.  * @{
  31.  */
  32. /**
  33.  * @file
  34.  * Glue code which is commonod to all FS implementations.
  35.  */
  36.  
  37. #include "libfs.h"
  38. #include "../../srv/vfs/vfs.h"
  39. #include <errno.h>
  40. #include <async.h>
  41. #include <ipc/ipc.h>
  42. #include <as.h>
  43. #include <assert.h>
  44. #include <dirent.h>
  45.  
  46. /** Register file system server.
  47.  *
  48.  * This function abstracts away the tedious registration protocol from
  49.  * file system implementations and lets them to reuse this registration glue
  50.  * code.
  51.  *
  52.  * @param vfs_phone Open phone for communication with VFS.
  53.  * @param reg       File system registration structure. It will be
  54.  *          initialized by this function.
  55.  * @param info      VFS info structure supplied by the file system
  56.  *          implementation.
  57.  * @param conn      Connection fibril for handling all calls originating in
  58.  *          VFS.
  59.  *
  60.  * @return      EOK on success or a non-zero error code on errror.
  61.  */
  62. int fs_register(int vfs_phone, fs_reg_t *reg, vfs_info_t *info,
  63.     async_client_conn_t conn)
  64. {
  65.     /*
  66.      * Tell VFS that we are here and want to get registered.
  67.      * We use the async framework because VFS will answer the request
  68.      * out-of-order, when it knows that the operation succeeded or failed.
  69.      */
  70.     ipc_call_t answer;
  71.     aid_t req = async_send_0(vfs_phone, VFS_REGISTER, &answer);
  72.  
  73.     /*
  74.      * Send our VFS info structure to VFS.
  75.      */
  76.     int rc = ipc_data_write_start(vfs_phone, info, sizeof(*info));
  77.     if (rc != EOK) {
  78.         async_wait_for(req, NULL);
  79.         return rc;
  80.     }
  81.  
  82.     /*
  83.      * Ask VFS for callback connection.
  84.      */
  85.     ipc_connect_to_me(vfs_phone, 0, 0, 0, &reg->vfs_phonehash);
  86.  
  87.     /*
  88.      * Allocate piece of address space for PLB.
  89.      */
  90.     reg->plb_ro = as_get_mappable_page(PLB_SIZE);
  91.     if (!reg->plb_ro) {
  92.         async_wait_for(req, NULL);
  93.         return ENOMEM;
  94.     }
  95.  
  96.     /*
  97.      * Request sharing the Path Lookup Buffer with VFS.
  98.      */
  99.     rc = ipc_share_in_start_0_0(vfs_phone, reg->plb_ro, PLB_SIZE);
  100.     if (rc) {
  101.         async_wait_for(req, NULL);
  102.         return rc;
  103.     }
  104.      
  105.     /*
  106.      * Pick up the answer for the request to the VFS_REQUEST call.
  107.      */
  108.     async_wait_for(req, NULL);
  109.     reg->fs_handle = (int) IPC_GET_ARG1(answer);
  110.    
  111.     /*
  112.      * Create a connection fibril to handle the callback connection.
  113.      */
  114.     async_new_connection(reg->vfs_phonehash, 0, NULL, conn);
  115.    
  116.     /*
  117.      * Tell the async framework that other connections are to be handled by
  118.      * the same connection fibril as well.
  119.      */
  120.     async_set_client_connection(conn);
  121.  
  122.     return IPC_GET_RETVAL(answer);
  123. }
  124.  
  125. /** Lookup VFS triplet by name in the file system name space.
  126.  *
  127.  * The path passed in the PLB must be in the canonical file system path format
  128.  * as returned by the canonify() function.
  129.  *
  130.  * @param ops       libfs operations structure with function pointers to
  131.  *          file system implementation
  132.  * @param fs_handle File system handle of the file system where to perform
  133.  *          the lookup.
  134.  * @param rid       Request ID of the VFS_LOOKUP request.
  135.  * @param request   VFS_LOOKUP request data itself.
  136.  */
  137. void libfs_lookup(libfs_ops_t *ops, int fs_handle, ipc_callid_t rid,
  138.     ipc_call_t *request)
  139. {
  140.     unsigned next = IPC_GET_ARG1(*request);
  141.     unsigned last = IPC_GET_ARG2(*request);
  142.     int dev_handle = IPC_GET_ARG3(*request);
  143.     int lflag = IPC_GET_ARG4(*request);
  144.  
  145.     if (last < next)
  146.         last += PLB_SIZE;
  147.  
  148.     void *cur = ops->root_get();
  149.     void *tmp = ops->child_get(cur);
  150.  
  151.     if (ops->plb_get_char(next) == '/')
  152.         next++;     /* eat slash */
  153.    
  154.     char component[NAME_MAX + 1];
  155.     int len = 0;
  156.     while (tmp && next <= last) {
  157.  
  158.         /* collect the component */
  159.         if (ops->plb_get_char(next) != '/') {
  160.             if (len + 1 == NAME_MAX) {
  161.                 /* comopnent length overflow */
  162.                 ipc_answer_0(rid, ENAMETOOLONG);
  163.                 return;
  164.             }
  165.             component[len++] = ops->plb_get_char(next);
  166.             next++; /* process next character */
  167.             if (next <= last)
  168.                 continue;
  169.         }
  170.  
  171.         assert(len);
  172.         component[len] = '\0';
  173.         next++;     /* eat slash */
  174.         len = 0;
  175.  
  176.         /* match the component */
  177.         while (tmp && !ops->match(tmp, component))
  178.             tmp = ops->sibling_get(tmp);
  179.  
  180.         /* handle miss: match amongst siblings */
  181.         if (!tmp) {
  182.             if ((next > last) && (lflag & L_CREATE)) {
  183.                 /* no components left and L_CREATE specified */
  184.                 if (!ops->is_directory(cur)) {
  185.                     ipc_answer_0(rid, ENOTDIR);
  186.                     return;
  187.                 }
  188.                 void *nodep = ops->create(lflag);
  189.                 if (nodep) {
  190.                     if (!ops->link(cur, nodep, component)) {
  191.                         ops->destroy(nodep);
  192.                         ipc_answer_0(rid, ENOSPC);
  193.                     } else {
  194.                         ipc_answer_5(rid, EOK,
  195.                             fs_handle, dev_handle,
  196.                             ops->index_get(nodep), 0,
  197.                             ops->lnkcnt_get(nodep));
  198.                     }
  199.                 } else {
  200.                     ipc_answer_0(rid, ENOSPC);
  201.                 }
  202.                 return;
  203.             }
  204.             ipc_answer_0(rid, ENOENT);
  205.             return;
  206.         }
  207.  
  208.         /* descend one level */
  209.         cur = tmp;
  210.         tmp = ops->child_get(tmp);
  211.     }
  212.  
  213.     /* handle miss: excessive components */
  214.     if (!tmp && next <= last) {
  215.         if (lflag & L_CREATE) {
  216.             if (!ops->is_directory(cur)) {
  217.                 ipc_answer_0(rid, ENOTDIR);
  218.                 return;
  219.             }
  220.  
  221.             /* collect next component */
  222.             while (next <= last) {
  223.                 if (ops->plb_get_char(next) == '/') {
  224.                     /* more than one component */
  225.                     ipc_answer_0(rid, ENOENT);
  226.                     return;
  227.                 }
  228.                 if (len + 1 == NAME_MAX) {
  229.                     /* component length overflow */
  230.                     ipc_answer_0(rid, ENAMETOOLONG);
  231.                     return;
  232.                 }
  233.                 component[len++] = ops->plb_get_char(next);
  234.                 next++; /* process next character */
  235.             }
  236.             assert(len);
  237.             component[len] = '\0';
  238.             len = 0;
  239.                
  240.             void *nodep = ops->create(lflag);
  241.             if (nodep) {
  242.                 if (!ops->link(cur, nodep, component)) {
  243.                     ops->destroy(nodep);
  244.                     ipc_answer_0(rid, ENOSPC);
  245.                 } else {
  246.                     ipc_answer_5(rid, EOK,
  247.                         fs_handle, dev_handle,
  248.                         ops->index_get(nodep), 0,
  249.                         ops->lnkcnt_get(nodep));
  250.                 }
  251.             } else {
  252.                 ipc_answer_0(rid, ENOSPC);
  253.             }
  254.             return;
  255.         }
  256.         ipc_answer_0(rid, ENOENT);
  257.         return;
  258.     }
  259.  
  260.     /* handle hit */
  261.     if (lflag & L_DESTROY) {
  262.         unsigned old_lnkcnt = ops->lnkcnt_get(cur);
  263.         int res = ops->unlink(cur);
  264.         ipc_answer_5(rid, (ipcarg_t)res, fs_handle, dev_handle,
  265.             ops->index_get(cur), ops->size_get(cur), old_lnkcnt);
  266.         return;
  267.     }
  268.     if ((lflag & (L_CREATE | L_EXCLUSIVE)) == (L_CREATE | L_EXCLUSIVE)) {
  269.         ipc_answer_0(rid, EEXIST);
  270.         return;
  271.     }
  272.     if ((lflag & L_FILE) && (ops->is_directory(cur))) {
  273.         ipc_answer_0(rid, EISDIR);
  274.         return;
  275.     }
  276.     if ((lflag & L_DIRECTORY) && (ops->is_file(cur))) {
  277.         ipc_answer_0(rid, ENOTDIR);
  278.         return;
  279.     }
  280.  
  281.     ipc_answer_5(rid, EOK, fs_handle, dev_handle, ops->index_get(cur),
  282.         ops->size_get(cur), ops->lnkcnt_get(cur));
  283. }
  284.  
  285. /** @}
  286.  */
  287.