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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.     int index = IPC_GET_ARG5(*request); /* when L_LINK specified */
  145.  
  146.     if (last < next)
  147.         last += PLB_SIZE;
  148.  
  149.     void *par = NULL;
  150.     void *cur = ops->root_get();
  151.     void *tmp = ops->child_get(cur);
  152.  
  153.     if (ops->plb_get_char(next) == '/')
  154.         next++;     /* eat slash */
  155.    
  156.     char component[NAME_MAX + 1];
  157.     int len = 0;
  158.     while (tmp && next <= last) {
  159.  
  160.         /* collect the component */
  161.         if (ops->plb_get_char(next) != '/') {
  162.             if (len + 1 == NAME_MAX) {
  163.                 /* comopnent length overflow */
  164.                 ipc_answer_0(rid, ENAMETOOLONG);
  165.                 return;
  166.             }
  167.             component[len++] = ops->plb_get_char(next);
  168.             next++; /* process next character */
  169.             if (next <= last)
  170.                 continue;
  171.         }
  172.  
  173.         assert(len);
  174.         component[len] = '\0';
  175.         next++;     /* eat slash */
  176.         len = 0;
  177.  
  178.         /* match the component */
  179.         while (tmp && !ops->match(cur, tmp, component))
  180.             tmp = ops->sibling_get(tmp);
  181.  
  182.         /* handle miss: match amongst siblings */
  183.         if (!tmp) {
  184.             if (next <= last) {
  185.                 /* there are unprocessed components */
  186.                 ipc_answer_0(rid, ENOENT);
  187.                 return;
  188.             }
  189.             /* miss in the last component */
  190.             if (lflag & (L_CREATE | L_LINK)) {
  191.                 /* request to create a new link */
  192.                 if (!ops->is_directory(cur)) {
  193.                     ipc_answer_0(rid, ENOTDIR);
  194.                     return;
  195.                 }
  196.                 void *nodep;
  197.                 if (lflag & L_CREATE)
  198.                     nodep = ops->create(lflag);
  199.                 else
  200.                     nodep = ops->node_get(fs_handle,
  201.                         dev_handle, index);
  202.                 if (nodep) {
  203.                     if (!ops->link(cur, nodep, component)) {
  204.                         if (lflag & L_CREATE)
  205.                             ops->destroy(nodep);
  206.                         ipc_answer_0(rid, ENOSPC);
  207.                     } else {
  208.                         ipc_answer_5(rid, EOK,
  209.                             fs_handle, dev_handle,
  210.                             ops->index_get(nodep),
  211.                             ops->size_get(nodep),
  212.                             ops->lnkcnt_get(nodep));
  213.                     }
  214.                 } else {
  215.                     ipc_answer_0(rid, ENOSPC);
  216.                 }
  217.                 return;
  218.             } else if (lflag & L_PARENT) {
  219.                 /* return parent */
  220.                 ipc_answer_5(rid, EOK, fs_handle, dev_handle,
  221.                     ops->index_get(cur), ops->size_get(cur),
  222.                     ops->lnkcnt_get(cur));
  223.             }
  224.             ipc_answer_0(rid, ENOENT);
  225.             return;
  226.         }
  227.  
  228.         /* descend one level */
  229.         par = cur;
  230.         cur = tmp;
  231.         tmp = ops->child_get(tmp);
  232.     }
  233.  
  234.     /* handle miss: excessive components */
  235.     if (!tmp && next <= last) {
  236.         if (lflag & (L_CREATE | L_LINK)) {
  237.             if (!ops->is_directory(cur)) {
  238.                 ipc_answer_0(rid, ENOTDIR);
  239.                 return;
  240.             }
  241.  
  242.             /* collect next component */
  243.             while (next <= last) {
  244.                 if (ops->plb_get_char(next) == '/') {
  245.                     /* more than one component */
  246.                     ipc_answer_0(rid, ENOENT);
  247.                     return;
  248.                 }
  249.                 if (len + 1 == NAME_MAX) {
  250.                     /* component length overflow */
  251.                     ipc_answer_0(rid, ENAMETOOLONG);
  252.                     return;
  253.                 }
  254.                 component[len++] = ops->plb_get_char(next);
  255.                 next++; /* process next character */
  256.             }
  257.             assert(len);
  258.             component[len] = '\0';
  259.             len = 0;
  260.                
  261.             void *nodep;
  262.             if (lflag & L_CREATE)
  263.                 nodep = ops->create(lflag);
  264.             else
  265.                 nodep = ops->node_get(fs_handle, dev_handle,
  266.                     index);
  267.             if (nodep) {
  268.                 if (!ops->link(cur, nodep, component)) {
  269.                     if (lflag & L_CREATE)
  270.                         ops->destroy(nodep);
  271.                     ipc_answer_0(rid, ENOSPC);
  272.                 } else {
  273.                     ipc_answer_5(rid, EOK,
  274.                         fs_handle, dev_handle,
  275.                         ops->index_get(nodep),
  276.                         ops->size_get(nodep),
  277.                         ops->lnkcnt_get(nodep));
  278.                 }
  279.             } else {
  280.                 ipc_answer_0(rid, ENOSPC);
  281.             }
  282.             return;
  283.         }
  284.         ipc_answer_0(rid, ENOENT);
  285.         return;
  286.     }
  287.  
  288.     /* handle hit */
  289.     if (lflag & L_PARENT) {
  290.         cur = par;
  291.         if (!cur) {
  292.             ipc_answer_0(rid, ENOENT);
  293.             return;
  294.         }
  295.     }
  296.     if (lflag & L_UNLINK) {
  297.         unsigned old_lnkcnt = ops->lnkcnt_get(cur);
  298.         int res = ops->unlink(par, cur);
  299.         ipc_answer_5(rid, (ipcarg_t)res, fs_handle, dev_handle,
  300.             ops->index_get(cur), ops->size_get(cur), old_lnkcnt);
  301.         return;
  302.     }
  303.     if (((lflag & (L_CREATE | L_EXCLUSIVE)) == (L_CREATE | L_EXCLUSIVE)) ||
  304.         (lflag & L_LINK)) {
  305.         ipc_answer_0(rid, EEXIST);
  306.         return;
  307.     }
  308.     if ((lflag & L_FILE) && (ops->is_directory(cur))) {
  309.         ipc_answer_0(rid, EISDIR);
  310.         return;
  311.     }
  312.     if ((lflag & L_DIRECTORY) && (ops->is_file(cur))) {
  313.         ipc_answer_0(rid, ENOTDIR);
  314.         return;
  315.     }
  316.  
  317.     ipc_answer_5(rid, EOK, fs_handle, dev_handle, ops->index_get(cur),
  318.         ops->size_get(cur), ops->lnkcnt_get(cur));
  319. }
  320.  
  321. /** @}
  322.  */
  323.