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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, fs_handle_t 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.     dev_handle_t dev_handle = IPC_GET_ARG3(*request);
  143.     int lflag = IPC_GET_ARG4(*request);
  144.     fs_index_t index = IPC_GET_ARG5(*request); /* when L_LINK specified */
  145.     char component[NAME_MAX + 1];
  146.     int len;
  147.  
  148.     if (last < next)
  149.         last += PLB_SIZE;
  150.  
  151.     void *par = NULL;
  152.     void *cur = ops->root_get(dev_handle);
  153.     void *tmp = NULL;
  154.  
  155.     if (ops->plb_get_char(next) == '/')
  156.         next++;     /* eat slash */
  157.    
  158.     while (next <= last && ops->has_children(cur)) {
  159.         /* collect the component */
  160.         len = 0;
  161.         while ((next <= last) &&  (ops->plb_get_char(next) != '/')) {
  162.             if (len + 1 == NAME_MAX) {
  163.                 /* comopnent length overflow */
  164.                 ipc_answer_0(rid, ENAMETOOLONG);
  165.                 goto out;
  166.             }
  167.             component[len++] = ops->plb_get_char(next);
  168.             next++; /* process next character */
  169.         }
  170.  
  171.         assert(len);
  172.         component[len] = '\0';
  173.         next++;     /* eat slash */
  174.  
  175.         /* match the component */
  176.         tmp = ops->match(cur, component);
  177.  
  178.         /* handle miss: match amongst siblings */
  179.         if (!tmp) {
  180.             if (next <= last) {
  181.                 /* there are unprocessed components */
  182.                 ipc_answer_0(rid, ENOENT);
  183.                 goto out;
  184.             }
  185.             /* miss in the last component */
  186.             if (lflag & (L_CREATE | L_LINK)) {
  187.                 /* request to create a new link */
  188.                 if (!ops->is_directory(cur)) {
  189.                     ipc_answer_0(rid, ENOTDIR);
  190.                     goto out;
  191.                 }
  192.                 void *nodep;
  193.                 if (lflag & L_CREATE)
  194.                     nodep = ops->create(lflag);
  195.                 else
  196.                     nodep = ops->node_get(dev_handle,
  197.                         index);
  198.                 if (nodep) {
  199.                     if (!ops->link(cur, nodep, component)) {
  200.                         if (lflag & L_CREATE) {
  201.                             (void)ops->destroy(
  202.                                 nodep);
  203.                         }
  204.                         ipc_answer_0(rid, ENOSPC);
  205.                     } else {
  206.                         ipc_answer_5(rid, EOK,
  207.                             fs_handle, dev_handle,
  208.                             ops->index_get(nodep),
  209.                             ops->size_get(nodep),
  210.                             ops->lnkcnt_get(nodep));
  211.                         ops->node_put(nodep);
  212.                     }
  213.                 } else {
  214.                     ipc_answer_0(rid, ENOSPC);
  215.                 }
  216.                 goto out;
  217.             } else if (lflag & L_PARENT) {
  218.                 /* return parent */
  219.                 ipc_answer_5(rid, EOK, fs_handle, dev_handle,
  220.                     ops->index_get(cur), ops->size_get(cur),
  221.                     ops->lnkcnt_get(cur));
  222.             }
  223.             ipc_answer_0(rid, ENOENT);
  224.             goto out;
  225.         }
  226.  
  227.         if (par)
  228.             ops->node_put(par);
  229.  
  230.         /* descend one level */
  231.         par = cur;
  232.         cur = tmp;
  233.         tmp = NULL;
  234.     }
  235.  
  236.     /* handle miss: excessive components */
  237.     if (next <= last && !ops->has_children(cur)) {
  238.         if (lflag & (L_CREATE | L_LINK)) {
  239.             if (!ops->is_directory(cur)) {
  240.                 ipc_answer_0(rid, ENOTDIR);
  241.                 goto out;
  242.             }
  243.  
  244.             /* collect next component */
  245.             len = 0;
  246.             while (next <= last) {
  247.                 if (ops->plb_get_char(next) == '/') {
  248.                     /* more than one component */
  249.                     ipc_answer_0(rid, ENOENT);
  250.                     goto out;
  251.                 }
  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.             assert(len);
  261.             component[len] = '\0';
  262.                
  263.             void *nodep;
  264.             if (lflag & L_CREATE)
  265.                 nodep = ops->create(lflag);
  266.             else
  267.                 nodep = ops->node_get(dev_handle, index);
  268.             if (nodep) {
  269.                 if (!ops->link(cur, nodep, component)) {
  270.                     if (lflag & L_CREATE)
  271.                         (void)ops->destroy(nodep);
  272.                     ipc_answer_0(rid, ENOSPC);
  273.                 } else {
  274.                     ipc_answer_5(rid, EOK,
  275.                         fs_handle, dev_handle,
  276.                         ops->index_get(nodep),
  277.                         ops->size_get(nodep),
  278.                         ops->lnkcnt_get(nodep));
  279.                     ops->node_put(nodep);
  280.                 }
  281.             } else {
  282.                 ipc_answer_0(rid, ENOSPC);
  283.             }
  284.             goto out;
  285.         }
  286.         ipc_answer_0(rid, ENOENT);
  287.         goto out;
  288.     }
  289.  
  290.     /* handle hit */
  291.     if (lflag & L_PARENT) {
  292.         ops->node_put(cur);
  293.         cur = par;
  294.         par = NULL;
  295.         if (!cur) {
  296.             ipc_answer_0(rid, ENOENT);
  297.             goto out;
  298.         }
  299.     }
  300.     if (lflag & L_UNLINK) {
  301.         unsigned old_lnkcnt = ops->lnkcnt_get(cur);
  302.         int res = ops->unlink(par, cur);
  303.         ipc_answer_5(rid, (ipcarg_t)res, fs_handle, dev_handle,
  304.             ops->index_get(cur), ops->size_get(cur), old_lnkcnt);
  305.         goto out;
  306.     }
  307.     if (((lflag & (L_CREATE | L_EXCLUSIVE)) == (L_CREATE | L_EXCLUSIVE)) ||
  308.         (lflag & L_LINK)) {
  309.         ipc_answer_0(rid, EEXIST);
  310.         goto out;
  311.     }
  312.     if ((lflag & L_FILE) && (ops->is_directory(cur))) {
  313.         ipc_answer_0(rid, EISDIR);
  314.         goto out;
  315.     }
  316.     if ((lflag & L_DIRECTORY) && (ops->is_file(cur))) {
  317.         ipc_answer_0(rid, ENOTDIR);
  318.         goto out;
  319.     }
  320.  
  321.     ipc_answer_5(rid, EOK, fs_handle, dev_handle, ops->index_get(cur),
  322.         ops->size_get(cur), ops->lnkcnt_get(cur));
  323.  
  324. out:
  325.     if (par)
  326.         ops->node_put(par);
  327.     if (cur)
  328.         ops->node_put(cur);
  329.     if (tmp)
  330.         ops->node_put(tmp);
  331. }
  332.  
  333. /** @}
  334.  */
  335.