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