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  1. /*
  2.  * Copyright (c) 2009 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. void fs_node_initialize(fs_node_t *fn)
  126. {
  127.     memset(fn, 0, sizeof(fs_node_t));
  128. }
  129.  
  130. void libfs_mount(libfs_ops_t *ops, fs_handle_t fs_handle, ipc_callid_t rid,
  131.     ipc_call_t *request)
  132. {
  133.     dev_handle_t mp_dev_handle = (dev_handle_t) IPC_GET_ARG1(*request);
  134.     fs_index_t mp_fs_index = (fs_index_t) IPC_GET_ARG2(*request);
  135.     fs_handle_t mr_fs_handle = (fs_handle_t) IPC_GET_ARG3(*request);
  136.     dev_handle_t mr_dev_handle = (dev_handle_t) IPC_GET_ARG4(*request);
  137.     int res;
  138.     ipcarg_t rc;
  139.  
  140.     ipc_call_t call;
  141.     ipc_callid_t callid;
  142.  
  143.     /* accept the phone */
  144.     callid = async_get_call(&call);
  145.     int mountee_phone = (int)IPC_GET_ARG1(call);
  146.     if ((IPC_GET_METHOD(call) != IPC_M_CONNECTION_CLONE) ||
  147.         mountee_phone < 0) {
  148.         ipc_answer_0(callid, EINVAL);
  149.         ipc_answer_0(rid, EINVAL);
  150.         return;
  151.     }
  152.     ipc_answer_0(callid, EOK);  /* acknowledge the mountee_phone */
  153.    
  154.     res = ipc_data_write_receive(&callid, NULL);
  155.     if (!res) {
  156.         ipc_hangup(mountee_phone);
  157.         ipc_answer_0(callid, EINVAL);
  158.         ipc_answer_0(rid, EINVAL);
  159.         return;
  160.     }
  161.  
  162.     fs_node_t *fn = ops->node_get(mp_dev_handle, mp_fs_index);
  163.     if (!fn) {
  164.         ipc_hangup(mountee_phone);
  165.         ipc_answer_0(callid, ENOENT);
  166.         ipc_answer_0(rid, ENOENT);
  167.         return;
  168.     }
  169.  
  170.     if (fn->mp_data.mp_active) {
  171.         ipc_hangup(mountee_phone);
  172.         ops->node_put(fn);
  173.         ipc_answer_0(callid, EBUSY);
  174.         ipc_answer_0(rid, EBUSY);
  175.         return;
  176.     }
  177.  
  178.     rc = async_req_0_0(mountee_phone, IPC_M_CONNECT_ME);
  179.     if (rc != 0) {
  180.         ipc_hangup(mountee_phone);
  181.         ops->node_put(fn);
  182.         ipc_answer_0(callid, rc);
  183.         ipc_answer_0(rid, rc);
  184.         return;
  185.     }
  186.    
  187.     ipc_call_t answer;
  188.     aid_t msg = async_send_1(mountee_phone, VFS_MOUNTED, mr_dev_handle,
  189.         &answer);
  190.     ipc_forward_fast(callid, mountee_phone, 0, 0, 0, IPC_FF_ROUTE_FROM_ME);
  191.     async_wait_for(msg, &rc);
  192.    
  193.     if (rc == EOK) {
  194.         fn->mp_data.mp_active = true;
  195.         fn->mp_data.fs_handle = mr_fs_handle;
  196.         fn->mp_data.dev_handle = mr_dev_handle;
  197.         fn->mp_data.phone = mountee_phone;
  198.     }
  199.     /*
  200.      * Do not release the FS node so that it stays in memory.
  201.      */
  202.     ipc_answer_3(rid, rc, IPC_GET_ARG1(answer), IPC_GET_ARG2(answer),
  203.         IPC_GET_ARG3(answer));
  204. }
  205.  
  206. /** Lookup VFS triplet by name in the file system name space.
  207.  *
  208.  * The path passed in the PLB must be in the canonical file system path format
  209.  * as returned by the canonify() function.
  210.  *
  211.  * @param ops       libfs operations structure with function pointers to
  212.  *          file system implementation
  213.  * @param fs_handle File system handle of the file system where to perform
  214.  *          the lookup.
  215.  * @param rid       Request ID of the VFS_LOOKUP request.
  216.  * @param request   VFS_LOOKUP request data itself.
  217.  */
  218. void libfs_lookup(libfs_ops_t *ops, fs_handle_t fs_handle, ipc_callid_t rid,
  219.     ipc_call_t *request)
  220. {
  221.     unsigned first = IPC_GET_ARG1(*request);
  222.     unsigned last = IPC_GET_ARG2(*request);
  223.     unsigned next = first;
  224.     dev_handle_t dev_handle = IPC_GET_ARG3(*request);
  225.     int lflag = IPC_GET_ARG4(*request);
  226.     fs_index_t index = IPC_GET_ARG5(*request); /* when L_LINK specified */
  227.     char component[NAME_MAX + 1];
  228.     int len;
  229.  
  230.     if (last < next)
  231.         last += PLB_SIZE;
  232.  
  233.     fs_node_t *par = NULL;
  234.     fs_node_t *cur = ops->root_get(dev_handle);
  235.     fs_node_t *tmp = NULL;
  236.  
  237.     if (cur->mp_data.mp_active) {
  238.         ipc_forward_slow(rid, cur->mp_data.phone, VFS_LOOKUP,
  239.             next, last, cur->mp_data.dev_handle, lflag, index,
  240.             IPC_FF_ROUTE_FROM_ME);
  241.         ops->node_put(cur);
  242.         return;
  243.     }
  244.  
  245.     if (ops->plb_get_char(next) == '/')
  246.         next++;     /* eat slash */
  247.    
  248.     while (next <= last && ops->has_children(cur)) {
  249.         /* collect the component */
  250.         len = 0;
  251.         while ((next <= last) &&  (ops->plb_get_char(next) != '/')) {
  252.             if (len + 1 == NAME_MAX) {
  253.                 /* component length overflow */
  254.                 ipc_answer_0(rid, ENAMETOOLONG);
  255.                 goto out;
  256.             }
  257.             component[len++] = ops->plb_get_char(next);
  258.             next++; /* process next character */
  259.         }
  260.  
  261.         assert(len);
  262.         component[len] = '\0';
  263.         next++;     /* eat slash */
  264.  
  265.         /* match the component */
  266.         tmp = ops->match(cur, component);
  267.         if (tmp && tmp->mp_data.mp_active) {
  268.             if (next > last)
  269.                 next = last = first;
  270.             else
  271.                 next--;
  272.                
  273.             ipc_forward_slow(rid, tmp->mp_data.phone, VFS_LOOKUP,
  274.                 next, last, tmp->mp_data.dev_handle, lflag, index,
  275.                 IPC_FF_ROUTE_FROM_ME);
  276.             ops->node_put(cur);
  277.             ops->node_put(tmp);
  278.             if (par)
  279.                 ops->node_put(par);
  280.             return;
  281.         }
  282.  
  283.         /* handle miss: match amongst siblings */
  284.         if (!tmp) {
  285.             if (next <= last) {
  286.                 /* there are unprocessed components */
  287.                 ipc_answer_0(rid, ENOENT);
  288.                 goto out;
  289.             }
  290.             /* miss in the last component */
  291.             if (lflag & (L_CREATE | L_LINK)) {
  292.                 /* request to create a new link */
  293.                 if (!ops->is_directory(cur)) {
  294.                     ipc_answer_0(rid, ENOTDIR);
  295.                     goto out;
  296.                 }
  297.                 fs_node_t *fn;
  298.                 if (lflag & L_CREATE)
  299.                     fn = ops->create(dev_handle, lflag);
  300.                 else
  301.                     fn = ops->node_get(dev_handle,
  302.                         index);
  303.                 if (fn) {
  304.                     int rc;
  305.  
  306.                     rc = ops->link(cur, fn, component);
  307.                     if (rc != EOK) {
  308.                         if (lflag & L_CREATE) {
  309.                             (void)ops->destroy(fn);
  310.                         }
  311.                         ipc_answer_0(rid, rc);
  312.                     } else {
  313.                         ipc_answer_5(rid, EOK,
  314.                             fs_handle, dev_handle,
  315.                             ops->index_get(fn),
  316.                             ops->size_get(fn),
  317.                             ops->lnkcnt_get(fn));
  318.                         ops->node_put(fn);
  319.                     }
  320.                 } else {
  321.                     ipc_answer_0(rid, ENOSPC);
  322.                 }
  323.                 goto out;
  324.             }
  325.             ipc_answer_0(rid, ENOENT);
  326.             goto out;
  327.         }
  328.  
  329.         if (par)
  330.             ops->node_put(par);
  331.  
  332.         /* descend one level */
  333.         par = cur;
  334.         cur = tmp;
  335.         tmp = NULL;
  336.     }
  337.  
  338.     /* handle miss: excessive components */
  339.     if (next <= last && !ops->has_children(cur)) {
  340.         if (lflag & (L_CREATE | L_LINK)) {
  341.             if (!ops->is_directory(cur)) {
  342.                 ipc_answer_0(rid, ENOTDIR);
  343.                 goto out;
  344.             }
  345.  
  346.             /* collect next component */
  347.             len = 0;
  348.             while (next <= last) {
  349.                 if (ops->plb_get_char(next) == '/') {
  350.                     /* more than one component */
  351.                     ipc_answer_0(rid, ENOENT);
  352.                     goto out;
  353.                 }
  354.                 if (len + 1 == NAME_MAX) {
  355.                     /* component length overflow */
  356.                     ipc_answer_0(rid, ENAMETOOLONG);
  357.                     goto out;
  358.                 }
  359.                 component[len++] = ops->plb_get_char(next);
  360.                 next++; /* process next character */
  361.             }
  362.             assert(len);
  363.             component[len] = '\0';
  364.                
  365.             fs_node_t *fn;
  366.             if (lflag & L_CREATE)
  367.                 fn = ops->create(dev_handle, lflag);
  368.             else
  369.                 fn = ops->node_get(dev_handle, index);
  370.             if (fn) {
  371.                 int rc;
  372.  
  373.                 rc = ops->link(cur, fn, component);
  374.                 if (rc != EOK) {
  375.                     if (lflag & L_CREATE)
  376.                         (void)ops->destroy(fn);
  377.                     ipc_answer_0(rid, rc);
  378.                 } else {
  379.                     ipc_answer_5(rid, EOK,
  380.                         fs_handle, dev_handle,
  381.                         ops->index_get(fn),
  382.                         ops->size_get(fn),
  383.                         ops->lnkcnt_get(fn));
  384.                     ops->node_put(fn);
  385.                 }
  386.             } else {
  387.                 ipc_answer_0(rid, ENOSPC);
  388.             }
  389.             goto out;
  390.         }
  391.         ipc_answer_0(rid, ENOENT);
  392.         goto out;
  393.     }
  394.  
  395.     /* handle hit */
  396.     if (lflag & L_UNLINK) {
  397.         unsigned old_lnkcnt = ops->lnkcnt_get(cur);
  398.         int res = ops->unlink(par, cur, component);
  399.         ipc_answer_5(rid, (ipcarg_t)res, fs_handle, dev_handle,
  400.             ops->index_get(cur), ops->size_get(cur), old_lnkcnt);
  401.         goto out;
  402.     }
  403.     if (((lflag & (L_CREATE | L_EXCLUSIVE)) == (L_CREATE | L_EXCLUSIVE)) ||
  404.         (lflag & L_LINK)) {
  405.         ipc_answer_0(rid, EEXIST);
  406.         goto out;
  407.     }
  408.     if ((lflag & L_FILE) && (ops->is_directory(cur))) {
  409.         ipc_answer_0(rid, EISDIR);
  410.         goto out;
  411.     }
  412.     if ((lflag & L_DIRECTORY) && (ops->is_file(cur))) {
  413.         ipc_answer_0(rid, ENOTDIR);
  414.         goto out;
  415.     }
  416.  
  417.     ipc_answer_5(rid, EOK, fs_handle, dev_handle, ops->index_get(cur),
  418.         ops->size_get(cur), ops->lnkcnt_get(cur));
  419.  
  420. out:
  421.     if (par)
  422.         ops->node_put(par);
  423.     if (cur)
  424.         ops->node_put(cur);
  425.     if (tmp)
  426.         ops->node_put(tmp);
  427. }
  428.  
  429. /** @}
  430.  */
  431.