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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 fs
  30.  * @{
  31.  */
  32.  
  33. /**
  34.  * @file vfs_ops.c
  35.  * @brief Operations that VFS offers to its clients.
  36.  */
  37.  
  38. #include "vfs.h"
  39. #include <ipc/ipc.h>
  40. #include <async.h>
  41. #include <errno.h>
  42. #include <stdio.h>
  43. #include <stdlib.h>
  44. #include <string.h>
  45. #include <bool.h>
  46. #include <fibril_sync.h>
  47. #include <adt/list.h>
  48. #include <unistd.h>
  49. #include <ctype.h>
  50. #include <fcntl.h>
  51. #include <assert.h>
  52. #include <vfs/canonify.h>
  53.  
  54. /* Forward declarations of static functions. */
  55. static int vfs_truncate_internal(fs_handle_t, dev_handle_t, fs_index_t, size_t);
  56.  
  57. /**
  58.  * This rwlock prevents the race between a triplet-to-VFS-node resolution and a
  59.  * concurrent VFS operation which modifies the file system namespace.
  60.  */
  61. FIBRIL_RWLOCK_INITIALIZE(namespace_rwlock);
  62.  
  63. vfs_pair_t rootfs = {
  64.     .fs_handle = 0,
  65.     .dev_handle = 0
  66. };
  67.  
  68. static void vfs_mount_internal(ipc_callid_t rid, dev_handle_t dev_handle,
  69.     fs_handle_t fs_handle, char *mp, char *opts)
  70. {
  71.     vfs_lookup_res_t mp_res;
  72.     vfs_lookup_res_t mr_res;
  73.     vfs_node_t *mp_node = NULL;
  74.     vfs_node_t *mr_node;
  75.     fs_index_t rindex;
  76.     size_t rsize;
  77.     unsigned rlnkcnt;
  78.     ipcarg_t rc;
  79.     int phone;
  80.     aid_t msg;
  81.     ipc_call_t answer;
  82.    
  83.     /* Resolve the path to the mountpoint. */
  84.     fibril_rwlock_write_lock(&namespace_rwlock);
  85.     if (rootfs.fs_handle) {
  86.         /* We already have the root FS. */
  87.         if (str_cmp(mp, "/") == 0) {
  88.             /* Trying to mount root FS over root FS */
  89.             fibril_rwlock_write_unlock(&namespace_rwlock);
  90.             ipc_answer_0(rid, EBUSY);
  91.             return;
  92.         }
  93.        
  94.         rc = vfs_lookup_internal(mp, L_DIRECTORY, &mp_res, NULL);
  95.         if (rc != EOK) {
  96.             /* The lookup failed for some reason. */
  97.             fibril_rwlock_write_unlock(&namespace_rwlock);
  98.             ipc_answer_0(rid, rc);
  99.             return;
  100.         }
  101.        
  102.         mp_node = vfs_node_get(&mp_res);
  103.         if (!mp_node) {
  104.             fibril_rwlock_write_unlock(&namespace_rwlock);
  105.             ipc_answer_0(rid, ENOMEM);
  106.             return;
  107.         }
  108.        
  109.         /*
  110.          * Now we hold a reference to mp_node.
  111.          * It will be dropped upon the corresponding VFS_IN_UNMOUNT.
  112.          * This prevents the mount point from being deleted.
  113.          */
  114.     } else {
  115.         /* We still don't have the root file system mounted. */
  116.         if (str_cmp(mp, "/") == 0) {
  117.             /*
  118.              * For this simple, but important case,
  119.              * we are almost done.
  120.              */
  121.            
  122.             /* Tell the mountee that it is being mounted. */
  123.             phone = vfs_grab_phone(fs_handle);
  124.             msg = async_send_1(phone, VFS_OUT_MOUNTED,
  125.                 (ipcarg_t) dev_handle, &answer);
  126.             /* send the mount options */
  127.             rc = ipc_data_write_start(phone, (void *)opts,
  128.                 str_size(opts));
  129.             if (rc != EOK) {
  130.                 async_wait_for(msg, NULL);
  131.                 vfs_release_phone(phone);
  132.                 fibril_rwlock_write_unlock(&namespace_rwlock);
  133.                 ipc_answer_0(rid, rc);
  134.                 return;
  135.             }
  136.             async_wait_for(msg, &rc);
  137.             vfs_release_phone(phone);
  138.            
  139.             if (rc != EOK) {
  140.                 fibril_rwlock_write_unlock(&namespace_rwlock);
  141.                 ipc_answer_0(rid, rc);
  142.                 return;
  143.             }
  144.  
  145.             rindex = (fs_index_t) IPC_GET_ARG1(answer);
  146.             rsize = (size_t) IPC_GET_ARG2(answer);
  147.             rlnkcnt = (unsigned) IPC_GET_ARG3(answer);
  148.            
  149.             mr_res.triplet.fs_handle = fs_handle;
  150.             mr_res.triplet.dev_handle = dev_handle;
  151.             mr_res.triplet.index = rindex;
  152.             mr_res.size = rsize;
  153.             mr_res.lnkcnt = rlnkcnt;
  154.             mr_res.type = VFS_NODE_DIRECTORY;
  155.            
  156.             rootfs.fs_handle = fs_handle;
  157.             rootfs.dev_handle = dev_handle;
  158.            
  159.             /* Add reference to the mounted root. */
  160.             mr_node = vfs_node_get(&mr_res);
  161.             assert(mr_node);
  162.            
  163.             fibril_rwlock_write_unlock(&namespace_rwlock);
  164.             ipc_answer_0(rid, rc);
  165.             return;
  166.         } else {
  167.             /*
  168.              * We can't resolve this without the root filesystem
  169.              * being mounted first.
  170.              */
  171.             fibril_rwlock_write_unlock(&namespace_rwlock);
  172.             ipc_answer_0(rid, ENOENT);
  173.             return;
  174.         }
  175.     }
  176.    
  177.     /*
  178.      * At this point, we have all necessary pieces: file system and device
  179.      * handles, and we know the mount point VFS node.
  180.      */
  181.    
  182.     int mountee_phone = vfs_grab_phone(fs_handle);
  183.     assert(mountee_phone >= 0);
  184.  
  185.     phone = vfs_grab_phone(mp_res.triplet.fs_handle);
  186.     msg = async_send_4(phone, VFS_OUT_MOUNT,
  187.         (ipcarg_t) mp_res.triplet.dev_handle,
  188.         (ipcarg_t) mp_res.triplet.index,
  189.         (ipcarg_t) fs_handle,
  190.         (ipcarg_t) dev_handle, &answer);
  191.    
  192.     /* send connection */
  193.     rc = async_req_1_0(phone, IPC_M_CONNECTION_CLONE, mountee_phone);
  194.     if (rc != EOK) {
  195.         async_wait_for(msg, NULL);
  196.         vfs_release_phone(mountee_phone);
  197.         vfs_release_phone(phone);
  198.         /* Mount failed, drop reference to mp_node. */
  199.         if (mp_node)
  200.             vfs_node_put(mp_node);
  201.         ipc_answer_0(rid, rc);
  202.         fibril_rwlock_write_unlock(&namespace_rwlock);
  203.         return;
  204.     }
  205.  
  206.     vfs_release_phone(mountee_phone);
  207.    
  208.     /* send the mount options */
  209.     rc = ipc_data_write_start(phone, (void *)opts, str_size(opts));
  210.     if (rc != EOK) {
  211.         async_wait_for(msg, NULL);
  212.         vfs_release_phone(phone);
  213.         /* Mount failed, drop reference to mp_node. */
  214.         if (mp_node)
  215.             vfs_node_put(mp_node);
  216.         fibril_rwlock_write_unlock(&namespace_rwlock);
  217.         ipc_answer_0(rid, rc);
  218.         return;
  219.     }
  220.     async_wait_for(msg, &rc);
  221.     vfs_release_phone(phone);
  222.    
  223.     if (rc == EOK) {
  224.         rindex = (fs_index_t) IPC_GET_ARG1(answer);
  225.         rsize = (size_t) IPC_GET_ARG2(answer);
  226.         rlnkcnt = (unsigned) IPC_GET_ARG3(answer);
  227.    
  228.         mr_res.triplet.fs_handle = fs_handle;
  229.         mr_res.triplet.dev_handle = dev_handle;
  230.         mr_res.triplet.index = rindex;
  231.         mr_res.size = rsize;
  232.         mr_res.lnkcnt = rlnkcnt;
  233.         mr_res.type = VFS_NODE_DIRECTORY;
  234.    
  235.         /* Add reference to the mounted root. */
  236.         mr_node = vfs_node_get(&mr_res);
  237.         assert(mr_node);
  238.     } else {
  239.         /* Mount failed, drop reference to mp_node. */
  240.         if (mp_node)
  241.             vfs_node_put(mp_node);
  242.     }
  243.  
  244.     ipc_answer_0(rid, rc);
  245.     fibril_rwlock_write_unlock(&namespace_rwlock);
  246. }
  247.  
  248. void vfs_mount(ipc_callid_t rid, ipc_call_t *request)
  249. {
  250.     /*
  251.      * We expect the library to do the device-name to device-handle
  252.      * translation for us, thus the device handle will arrive as ARG1
  253.      * in the request.
  254.      */
  255.     dev_handle_t dev_handle = (dev_handle_t) IPC_GET_ARG1(*request);
  256.    
  257.     /*
  258.      * Mount flags are passed as ARG2.
  259.      */
  260.     unsigned int flags = (unsigned int) IPC_GET_ARG2(*request);
  261.    
  262.     /*
  263.      * For now, don't make use of ARG3, but it can be used to
  264.      * carry mount options in the future.
  265.      */
  266.    
  267.     /* We want the client to send us the mount point. */
  268.     ipc_callid_t callid;
  269.     size_t size;
  270.     if (!ipc_data_write_receive(&callid, &size)) {
  271.         ipc_answer_0(callid, EINVAL);
  272.         ipc_answer_0(rid, EINVAL);
  273.         return;
  274.     }
  275.    
  276.     /* Check whether size is reasonable wrt. the mount point. */
  277.     if ((size < 1) || (size > MAX_PATH_LEN)) {
  278.         ipc_answer_0(callid, EINVAL);
  279.         ipc_answer_0(rid, EINVAL);
  280.         return;
  281.     }
  282.    
  283.     /* Allocate buffer for the mount point data being received. */
  284.     char *mp = malloc(size + 1);
  285.     if (!mp) {
  286.         ipc_answer_0(callid, ENOMEM);
  287.         ipc_answer_0(rid, ENOMEM);
  288.         return;
  289.     }
  290.    
  291.     /* Deliver the mount point. */
  292.     ipcarg_t retval = ipc_data_write_finalize(callid, mp, size);
  293.     if (retval != EOK) {
  294.         ipc_answer_0(rid, retval);
  295.         free(mp);
  296.         return;
  297.     }
  298.     mp[size] = '\0';
  299.    
  300.     /* Now we expect to receive the mount options. */
  301.     if (!ipc_data_write_receive(&callid, &size)) {
  302.         ipc_answer_0(callid, EINVAL);
  303.         ipc_answer_0(rid, EINVAL);
  304.         free(mp);
  305.         return;
  306.     }
  307.  
  308.     /* Check the offered options size. */
  309.     if (size < 0 || size > MAX_MNTOPTS_LEN) {
  310.         ipc_answer_0(callid, EINVAL);
  311.         ipc_answer_0(rid, EINVAL);
  312.         free(mp);
  313.         return;
  314.     }
  315.  
  316.     /* Allocate buffer for the mount options. */
  317.     char *opts = (char *) malloc(size + 1);
  318.     if (!opts) {
  319.         ipc_answer_0(callid, ENOMEM);
  320.         ipc_answer_0(rid, ENOMEM);
  321.         free(mp);
  322.         return;
  323.     }
  324.  
  325.     /* Deliver the mount options. */
  326.     retval = ipc_data_write_finalize(callid, opts, size);
  327.     if (retval != EOK) {
  328.         ipc_answer_0(rid, retval);
  329.         free(mp);
  330.         free(opts);
  331.         return;
  332.     }
  333.     opts[size] = '\0';
  334.    
  335.     /*
  336.      * Now, we expect the client to send us data with the name of the file
  337.      * system.
  338.      */
  339.     if (!ipc_data_write_receive(&callid, &size)) {
  340.         ipc_answer_0(callid, EINVAL);
  341.         ipc_answer_0(rid, EINVAL);
  342.         free(mp);
  343.         free(opts);
  344.         return;
  345.     }
  346.    
  347.     /*
  348.      * Don't receive more than is necessary for storing a full file system
  349.      * name.
  350.      */
  351.     if ((size < 1) || (size > FS_NAME_MAXLEN)) {
  352.         ipc_answer_0(callid, EINVAL);
  353.         ipc_answer_0(rid, EINVAL);
  354.         free(mp);
  355.         free(opts);
  356.         return;
  357.     }
  358.    
  359.     /*
  360.      * Allocate buffer for file system name.
  361.      */
  362.     char *fs_name = (char *) malloc(size + 1);
  363.     if (fs_name == NULL) {
  364.         ipc_answer_0(callid, ENOMEM);
  365.         ipc_answer_0(rid, ENOMEM);
  366.         free(mp);
  367.         free(opts);
  368.         return;
  369.     }
  370.    
  371.     /* Deliver the file system name. */
  372.     retval = ipc_data_write_finalize(callid, fs_name, size);
  373.     if (retval != EOK) {
  374.         ipc_answer_0(rid, retval);
  375.         free(mp);
  376.         free(opts);
  377.         free(fs_name);
  378.         return;
  379.     }
  380.     fs_name[size] = '\0';
  381.  
  382.     /*
  383.      * Wait for IPC_M_PING so that we can return an error if we don't know
  384.      * fs_name.
  385.      */
  386.     ipc_call_t data;
  387.     callid = async_get_call(&data);
  388.     if (IPC_GET_METHOD(data) != IPC_M_PING) {
  389.         ipc_answer_0(callid, ENOTSUP);
  390.         ipc_answer_0(rid, ENOTSUP);
  391.         free(mp);
  392.         free(opts);
  393.         free(fs_name);
  394.         return;
  395.     }
  396.  
  397.     /*
  398.      * Check if we know a file system with the same name as is in fs_name.
  399.      * This will also give us its file system handle.
  400.      */
  401.     fibril_mutex_lock(&fs_head_lock);
  402.     fs_handle_t fs_handle;
  403. recheck:
  404.     fs_handle = fs_name_to_handle(fs_name, false);
  405.     if (!fs_handle) {
  406.         if (flags & IPC_FLAG_BLOCKING) {
  407.             fibril_condvar_wait(&fs_head_cv, &fs_head_lock);
  408.             goto recheck;
  409.         }
  410.        
  411.         fibril_mutex_unlock(&fs_head_lock);
  412.         ipc_answer_0(callid, ENOENT);
  413.         ipc_answer_0(rid, ENOENT);
  414.         free(mp);
  415.         free(fs_name);
  416.         free(opts);
  417.         return;
  418.     }
  419.     fibril_mutex_unlock(&fs_head_lock);
  420.    
  421.     /* Acknowledge that we know fs_name. */
  422.     ipc_answer_0(callid, EOK);
  423.    
  424.     /* Do the mount */
  425.     vfs_mount_internal(rid, dev_handle, fs_handle, mp, opts);
  426.     free(mp);
  427.     free(fs_name);
  428.     free(opts);
  429. }
  430.  
  431. void vfs_open(ipc_callid_t rid, ipc_call_t *request)
  432. {
  433.     if (!vfs_files_init()) {
  434.         ipc_answer_0(rid, ENOMEM);
  435.         return;
  436.     }
  437.    
  438.     /*
  439.      * The POSIX interface is open(path, oflag, mode).
  440.      * We can receive oflags and mode along with the VFS_IN_OPEN call;
  441.      * the path will need to arrive in another call.
  442.      *
  443.      * We also receive one private, non-POSIX set of flags called lflag
  444.      * used to pass information to vfs_lookup_internal().
  445.      */
  446.     int lflag = IPC_GET_ARG1(*request);
  447.     int oflag = IPC_GET_ARG2(*request);
  448.     int mode = IPC_GET_ARG3(*request);
  449.     size_t len;
  450.    
  451.     /*
  452.      * Make sure that we are called with exactly one of L_FILE and
  453.      * L_DIRECTORY. Make sure that the user does not pass L_OPEN.
  454.      */
  455.     if (((lflag & (L_FILE | L_DIRECTORY)) == 0) ||
  456.         ((lflag & (L_FILE | L_DIRECTORY)) == (L_FILE | L_DIRECTORY)) ||
  457.         ((lflag & L_OPEN) != 0)) {
  458.         ipc_answer_0(rid, EINVAL);
  459.         return;
  460.     }
  461.    
  462.     if (oflag & O_CREAT)
  463.         lflag |= L_CREATE;
  464.     if (oflag & O_EXCL)
  465.         lflag |= L_EXCLUSIVE;
  466.    
  467.     ipc_callid_t callid;
  468.     if (!ipc_data_write_receive(&callid, &len)) {
  469.         ipc_answer_0(callid, EINVAL);
  470.         ipc_answer_0(rid, EINVAL);
  471.         return;
  472.     }
  473.    
  474.     char *path = malloc(len + 1);
  475.     if (!path) {
  476.         ipc_answer_0(callid, ENOMEM);
  477.         ipc_answer_0(rid, ENOMEM);
  478.         return;
  479.     }
  480.    
  481.     int rc;
  482.     if ((rc = ipc_data_write_finalize(callid, path, len))) {
  483.         ipc_answer_0(rid, rc);
  484.         free(path);
  485.         return;
  486.     }
  487.     path[len] = '\0';
  488.    
  489.     /*
  490.      * Avoid the race condition in which the file can be deleted before we
  491.      * find/create-and-lock the VFS node corresponding to the looked-up
  492.      * triplet.
  493.      */
  494.     if (lflag & L_CREATE)
  495.         fibril_rwlock_write_lock(&namespace_rwlock);
  496.     else
  497.         fibril_rwlock_read_lock(&namespace_rwlock);
  498.    
  499.     /* The path is now populated and we can call vfs_lookup_internal(). */
  500.     vfs_lookup_res_t lr;
  501.     rc = vfs_lookup_internal(path, lflag | L_OPEN, &lr, NULL);
  502.     if (rc != EOK) {
  503.         if (lflag & L_CREATE)
  504.             fibril_rwlock_write_unlock(&namespace_rwlock);
  505.         else
  506.             fibril_rwlock_read_unlock(&namespace_rwlock);
  507.         ipc_answer_0(rid, rc);
  508.         free(path);
  509.         return;
  510.     }
  511.    
  512.     /* Path is no longer needed. */
  513.     free(path);
  514.    
  515.     vfs_node_t *node = vfs_node_get(&lr);
  516.     if (lflag & L_CREATE)
  517.         fibril_rwlock_write_unlock(&namespace_rwlock);
  518.     else
  519.         fibril_rwlock_read_unlock(&namespace_rwlock);
  520.    
  521.     /* Truncate the file if requested and if necessary. */
  522.     if (oflag & O_TRUNC) {
  523.         fibril_rwlock_write_lock(&node->contents_rwlock);
  524.         if (node->size) {
  525.             rc = vfs_truncate_internal(node->fs_handle,
  526.                 node->dev_handle, node->index, 0);
  527.             if (rc) {
  528.                 fibril_rwlock_write_unlock(&node->contents_rwlock);
  529.                 vfs_node_put(node);
  530.                 ipc_answer_0(rid, rc);
  531.                 return;
  532.             }
  533.             node->size = 0;
  534.         }
  535.         fibril_rwlock_write_unlock(&node->contents_rwlock);
  536.     }
  537.    
  538.     /*
  539.      * Get ourselves a file descriptor and the corresponding vfs_file_t
  540.      * structure.
  541.      */
  542.     int fd = vfs_fd_alloc();
  543.     if (fd < 0) {
  544.         vfs_node_put(node);
  545.         ipc_answer_0(rid, fd);
  546.         return;
  547.     }
  548.     vfs_file_t *file = vfs_file_get(fd);
  549.     file->node = node;
  550.     if (oflag & O_APPEND)
  551.         file->append = true;
  552.    
  553.     /*
  554.      * The following increase in reference count is for the fact that the
  555.      * file is being opened and that a file structure is pointing to it.
  556.      * It is necessary so that the file will not disappear when
  557.      * vfs_node_put() is called. The reference will be dropped by the
  558.      * respective VFS_IN_CLOSE.
  559.      */
  560.     vfs_node_addref(node);
  561.     vfs_node_put(node);
  562.    
  563.     /* Success! Return the new file descriptor to the client. */
  564.     ipc_answer_1(rid, EOK, fd);
  565. }
  566.  
  567. void vfs_open_node(ipc_callid_t rid, ipc_call_t *request)
  568. {
  569.     // FIXME: check for sanity of the supplied fs, dev and index
  570.    
  571.     if (!vfs_files_init()) {
  572.         ipc_answer_0(rid, ENOMEM);
  573.         return;
  574.     }
  575.    
  576.     /*
  577.      * The interface is open_node(fs, dev, index, oflag).
  578.      */
  579.     vfs_lookup_res_t lr;
  580.    
  581.     lr.triplet.fs_handle = IPC_GET_ARG1(*request);
  582.     lr.triplet.dev_handle = IPC_GET_ARG2(*request);
  583.     lr.triplet.index = IPC_GET_ARG3(*request);
  584.     int oflag = IPC_GET_ARG4(*request);
  585.    
  586.     fibril_rwlock_read_lock(&namespace_rwlock);
  587.    
  588.     int rc = vfs_open_node_internal(&lr);
  589.     if (rc != EOK) {
  590.         fibril_rwlock_read_unlock(&namespace_rwlock);
  591.         ipc_answer_0(rid, rc);
  592.         return;
  593.     }
  594.    
  595.     vfs_node_t *node = vfs_node_get(&lr);
  596.     fibril_rwlock_read_unlock(&namespace_rwlock);
  597.    
  598.     /* Truncate the file if requested and if necessary. */
  599.     if (oflag & O_TRUNC) {
  600.         fibril_rwlock_write_lock(&node->contents_rwlock);
  601.         if (node->size) {
  602.             rc = vfs_truncate_internal(node->fs_handle,
  603.                 node->dev_handle, node->index, 0);
  604.             if (rc) {
  605.                 fibril_rwlock_write_unlock(&node->contents_rwlock);
  606.                 vfs_node_put(node);
  607.                 ipc_answer_0(rid, rc);
  608.                 return;
  609.             }
  610.             node->size = 0;
  611.         }
  612.         fibril_rwlock_write_unlock(&node->contents_rwlock);
  613.     }
  614.    
  615.     /*
  616.      * Get ourselves a file descriptor and the corresponding vfs_file_t
  617.      * structure.
  618.      */
  619.     int fd = vfs_fd_alloc();
  620.     if (fd < 0) {
  621.         vfs_node_put(node);
  622.         ipc_answer_0(rid, fd);
  623.         return;
  624.     }
  625.     vfs_file_t *file = vfs_file_get(fd);
  626.     file->node = node;
  627.     if (oflag & O_APPEND)
  628.         file->append = true;
  629.    
  630.     /*
  631.      * The following increase in reference count is for the fact that the
  632.      * file is being opened and that a file structure is pointing to it.
  633.      * It is necessary so that the file will not disappear when
  634.      * vfs_node_put() is called. The reference will be dropped by the
  635.      * respective VFS_IN_CLOSE.
  636.      */
  637.     vfs_node_addref(node);
  638.     vfs_node_put(node);
  639.    
  640.     /* Success! Return the new file descriptor to the client. */
  641.     ipc_answer_1(rid, EOK, fd);
  642. }
  643.  
  644. void vfs_sync(ipc_callid_t rid, ipc_call_t *request)
  645. {
  646.     int fd = IPC_GET_ARG1(*request);
  647.    
  648.     /* Lookup the file structure corresponding to the file descriptor. */
  649.     vfs_file_t *file = vfs_file_get(fd);
  650.     if (!file) {
  651.         ipc_answer_0(rid, ENOENT);
  652.         return;
  653.     }
  654.    
  655.     /*
  656.      * Lock the open file structure so that no other thread can manipulate
  657.      * the same open file at a time.
  658.      */
  659.     fibril_mutex_lock(&file->lock);
  660.     int fs_phone = vfs_grab_phone(file->node->fs_handle);
  661.    
  662.     /* Make a VFS_OUT_SYMC request at the destination FS server. */
  663.     aid_t msg;
  664.     ipc_call_t answer;
  665.     msg = async_send_2(fs_phone, VFS_OUT_SYNC, file->node->dev_handle,
  666.         file->node->index, &answer);
  667.  
  668.     /* Wait for reply from the FS server. */
  669.     ipcarg_t rc;
  670.     async_wait_for(msg, &rc);
  671.    
  672.     vfs_release_phone(fs_phone);
  673.     fibril_mutex_unlock(&file->lock);
  674.    
  675.     ipc_answer_0(rid, rc);
  676. }
  677.  
  678. void vfs_close(ipc_callid_t rid, ipc_call_t *request)
  679. {
  680.     int fd = IPC_GET_ARG1(*request);
  681.    
  682.     /* Lookup the file structure corresponding to the file descriptor. */
  683.     vfs_file_t *file = vfs_file_get(fd);
  684.     if (!file) {
  685.         ipc_answer_0(rid, ENOENT);
  686.         return;
  687.     }
  688.    
  689.     /*
  690.      * Lock the open file structure so that no other thread can manipulate
  691.      * the same open file at a time.
  692.      */
  693.     fibril_mutex_lock(&file->lock);
  694.     int fs_phone = vfs_grab_phone(file->node->fs_handle);
  695.    
  696.     /* Make a VFS_OUT_CLOSE request at the destination FS server. */
  697.     aid_t msg;
  698.     ipc_call_t answer;
  699.     msg = async_send_2(fs_phone, VFS_OUT_CLOSE, file->node->dev_handle,
  700.         file->node->index, &answer);
  701.  
  702.     /* Wait for reply from the FS server. */
  703.     ipcarg_t rc;
  704.     async_wait_for(msg, &rc);
  705.  
  706.     vfs_release_phone(fs_phone);
  707.     fibril_mutex_unlock(&file->lock);
  708.    
  709.     int retval = IPC_GET_ARG1(answer);
  710.     if (retval != EOK)
  711.         ipc_answer_0(rid, retval);
  712.    
  713.     retval = vfs_fd_free(fd);
  714.     ipc_answer_0(rid, retval);
  715. }
  716.  
  717. static void vfs_rdwr(ipc_callid_t rid, ipc_call_t *request, bool read)
  718. {
  719.  
  720.     /*
  721.      * The following code strongly depends on the fact that the files data
  722.      * structure can be only accessed by a single fibril and all file
  723.      * operations are serialized (i.e. the reads and writes cannot
  724.      * interleave and a file cannot be closed while it is being read).
  725.      *
  726.      * Additional synchronization needs to be added once the table of
  727.      * open files supports parallel access!
  728.      */
  729.  
  730.     int fd = IPC_GET_ARG1(*request);
  731.    
  732.     /* Lookup the file structure corresponding to the file descriptor. */
  733.     vfs_file_t *file = vfs_file_get(fd);
  734.     if (!file) {
  735.         ipc_answer_0(rid, ENOENT);
  736.         return;
  737.     }
  738.    
  739.     /*
  740.      * Now we need to receive a call with client's
  741.      * IPC_M_DATA_READ/IPC_M_DATA_WRITE request.
  742.      */
  743.     ipc_callid_t callid;
  744.     int res;
  745.     if (read)
  746.         res = ipc_data_read_receive(&callid, NULL);
  747.     else
  748.         res = ipc_data_write_receive(&callid, NULL);
  749.     if (!res) {
  750.         ipc_answer_0(callid, EINVAL);
  751.         ipc_answer_0(rid, EINVAL);
  752.         return;
  753.     }
  754.    
  755.     /*
  756.      * Lock the open file structure so that no other thread can manipulate
  757.      * the same open file at a time.
  758.      */
  759.     fibril_mutex_lock(&file->lock);
  760.  
  761.     /*
  762.      * Lock the file's node so that no other client can read/write to it at
  763.      * the same time.
  764.      */
  765.     if (read)
  766.         fibril_rwlock_read_lock(&file->node->contents_rwlock);
  767.     else
  768.         fibril_rwlock_write_lock(&file->node->contents_rwlock);
  769.  
  770.     if (file->node->type == VFS_NODE_DIRECTORY) {
  771.         /*
  772.          * Make sure that no one is modifying the namespace
  773.          * while we are in readdir().
  774.          */
  775.         assert(read);
  776.         fibril_rwlock_read_lock(&namespace_rwlock);
  777.     }
  778.    
  779.     int fs_phone = vfs_grab_phone(file->node->fs_handle);  
  780.    
  781.     /* Make a VFS_READ/VFS_WRITE request at the destination FS server. */
  782.     aid_t msg;
  783.     ipc_call_t answer;
  784.     if (!read && file->append)
  785.         file->pos = file->node->size;
  786.     msg = async_send_3(fs_phone, read ? VFS_OUT_READ : VFS_OUT_WRITE,
  787.         file->node->dev_handle, file->node->index, file->pos, &answer);
  788.    
  789.     /*
  790.      * Forward the IPC_M_DATA_READ/IPC_M_DATA_WRITE request to the
  791.      * destination FS server. The call will be routed as if sent by
  792.      * ourselves. Note that call arguments are immutable in this case so we
  793.      * don't have to bother.
  794.      */
  795.     ipc_forward_fast(callid, fs_phone, 0, 0, 0, IPC_FF_ROUTE_FROM_ME);
  796.  
  797.     /* Wait for reply from the FS server. */
  798.     ipcarg_t rc;
  799.     async_wait_for(msg, &rc);
  800.    
  801.     vfs_release_phone(fs_phone);
  802.    
  803.     size_t bytes = IPC_GET_ARG1(answer);
  804.  
  805.     if (file->node->type == VFS_NODE_DIRECTORY)
  806.         fibril_rwlock_read_unlock(&namespace_rwlock);
  807.    
  808.     /* Unlock the VFS node. */
  809.     if (read)
  810.         fibril_rwlock_read_unlock(&file->node->contents_rwlock);
  811.     else {
  812.         /* Update the cached version of node's size. */
  813.         if (rc == EOK)
  814.             file->node->size = IPC_GET_ARG2(answer);
  815.         fibril_rwlock_write_unlock(&file->node->contents_rwlock);
  816.     }
  817.    
  818.     /* Update the position pointer and unlock the open file. */
  819.     if (rc == EOK)
  820.         file->pos += bytes;
  821.     fibril_mutex_unlock(&file->lock);
  822.    
  823.     /*
  824.      * FS server's reply is the final result of the whole operation we
  825.      * return to the client.
  826.      */
  827.     ipc_answer_1(rid, rc, bytes);
  828. }
  829.  
  830. void vfs_read(ipc_callid_t rid, ipc_call_t *request)
  831. {
  832.     vfs_rdwr(rid, request, true);
  833. }
  834.  
  835. void vfs_write(ipc_callid_t rid, ipc_call_t *request)
  836. {
  837.     vfs_rdwr(rid, request, false);
  838. }
  839.  
  840. void vfs_seek(ipc_callid_t rid, ipc_call_t *request)
  841. {
  842.     int fd = (int) IPC_GET_ARG1(*request);
  843.     off_t off = (off_t) IPC_GET_ARG2(*request);
  844.     int whence = (int) IPC_GET_ARG3(*request);
  845.  
  846.  
  847.     /* Lookup the file structure corresponding to the file descriptor. */
  848.     vfs_file_t *file = vfs_file_get(fd);
  849.     if (!file) {
  850.         ipc_answer_0(rid, ENOENT);
  851.         return;
  852.     }
  853.  
  854.     off_t newpos;
  855.     fibril_mutex_lock(&file->lock);
  856.     if (whence == SEEK_SET) {
  857.         file->pos = off;
  858.         fibril_mutex_unlock(&file->lock);
  859.         ipc_answer_1(rid, EOK, off);
  860.         return;
  861.     }
  862.     if (whence == SEEK_CUR) {
  863.         if (file->pos + off < file->pos) {
  864.             fibril_mutex_unlock(&file->lock);
  865.             ipc_answer_0(rid, EOVERFLOW);
  866.             return;
  867.         }
  868.         file->pos += off;
  869.         newpos = file->pos;
  870.         fibril_mutex_unlock(&file->lock);
  871.         ipc_answer_1(rid, EOK, newpos);
  872.         return;
  873.     }
  874.     if (whence == SEEK_END) {
  875.         fibril_rwlock_read_lock(&file->node->contents_rwlock);
  876.         size_t size = file->node->size;
  877.         fibril_rwlock_read_unlock(&file->node->contents_rwlock);
  878.         if (size + off < size) {
  879.             fibril_mutex_unlock(&file->lock);
  880.             ipc_answer_0(rid, EOVERFLOW);
  881.             return;
  882.         }
  883.         newpos = size + off;
  884.         fibril_mutex_unlock(&file->lock);
  885.         ipc_answer_1(rid, EOK, newpos);
  886.         return;
  887.     }
  888.     fibril_mutex_unlock(&file->lock);
  889.     ipc_answer_0(rid, EINVAL);
  890. }
  891.  
  892. int
  893. vfs_truncate_internal(fs_handle_t fs_handle, dev_handle_t dev_handle,
  894.     fs_index_t index, size_t size)
  895. {
  896.     ipcarg_t rc;
  897.     int fs_phone;
  898.    
  899.     fs_phone = vfs_grab_phone(fs_handle);
  900.     rc = async_req_3_0(fs_phone, VFS_OUT_TRUNCATE, (ipcarg_t)dev_handle,
  901.         (ipcarg_t)index, (ipcarg_t)size);
  902.     vfs_release_phone(fs_phone);
  903.     return (int)rc;
  904. }
  905.  
  906. void vfs_truncate(ipc_callid_t rid, ipc_call_t *request)
  907. {
  908.     int fd = IPC_GET_ARG1(*request);
  909.     size_t size = IPC_GET_ARG2(*request);
  910.     int rc;
  911.  
  912.     vfs_file_t *file = vfs_file_get(fd);
  913.     if (!file) {
  914.         ipc_answer_0(rid, ENOENT);
  915.         return;
  916.     }
  917.     fibril_mutex_lock(&file->lock);
  918.  
  919.     fibril_rwlock_write_lock(&file->node->contents_rwlock);
  920.     rc = vfs_truncate_internal(file->node->fs_handle,
  921.         file->node->dev_handle, file->node->index, size);
  922.     if (rc == EOK)
  923.         file->node->size = size;
  924.     fibril_rwlock_write_unlock(&file->node->contents_rwlock);
  925.  
  926.     fibril_mutex_unlock(&file->lock);
  927.     ipc_answer_0(rid, (ipcarg_t)rc);
  928. }
  929.  
  930. void vfs_fstat(ipc_callid_t rid, ipc_call_t *request)
  931. {
  932.     int fd = IPC_GET_ARG1(*request);
  933.     size_t size = IPC_GET_ARG2(*request);
  934.     ipcarg_t rc;
  935.  
  936.     vfs_file_t *file = vfs_file_get(fd);
  937.     if (!file) {
  938.         ipc_answer_0(rid, ENOENT);
  939.         return;
  940.     }
  941.  
  942.     ipc_callid_t callid;
  943.     if (!ipc_data_read_receive(&callid, NULL)) {
  944.         ipc_answer_0(callid, EINVAL);
  945.         ipc_answer_0(rid, EINVAL);
  946.         return;
  947.     }
  948.  
  949.     fibril_mutex_lock(&file->lock);
  950.  
  951.     int fs_phone = vfs_grab_phone(file->node->fs_handle);
  952.    
  953.     aid_t msg;
  954.     msg = async_send_3(fs_phone, VFS_OUT_STAT, file->node->dev_handle,
  955.         file->node->index, true, NULL);
  956.     ipc_forward_fast(callid, fs_phone, 0, 0, 0, IPC_FF_ROUTE_FROM_ME);
  957.     async_wait_for(msg, &rc);
  958.     vfs_release_phone(fs_phone);
  959.  
  960.     fibril_mutex_unlock(&file->lock);
  961.     ipc_answer_0(rid, rc);
  962. }
  963.  
  964. void vfs_stat(ipc_callid_t rid, ipc_call_t *request)
  965. {
  966.     size_t len;
  967.     ipc_callid_t callid;
  968.  
  969.     if (!ipc_data_write_receive(&callid, &len)) {
  970.         ipc_answer_0(callid, EINVAL);
  971.         ipc_answer_0(rid, EINVAL);
  972.         return;
  973.     }
  974.     char *path = malloc(len + 1);
  975.     if (!path) {
  976.         ipc_answer_0(callid, ENOMEM);
  977.         ipc_answer_0(rid, ENOMEM);
  978.         return;
  979.     }
  980.     int rc;
  981.     if ((rc = ipc_data_write_finalize(callid, path, len))) {
  982.         ipc_answer_0(rid, rc);
  983.         free(path);
  984.         return;
  985.     }
  986.     path[len] = '\0';
  987.  
  988.     if (!ipc_data_read_receive(&callid, NULL)) {
  989.         free(path);
  990.         ipc_answer_0(callid, EINVAL);
  991.         ipc_answer_0(rid, EINVAL);
  992.         return;
  993.     }
  994.  
  995.     vfs_lookup_res_t lr;
  996.     fibril_rwlock_read_lock(&namespace_rwlock);
  997.     rc = vfs_lookup_internal(path, L_NONE, &lr, NULL);
  998.     free(path);
  999.     if (rc != EOK) {
  1000.         fibril_rwlock_read_unlock(&namespace_rwlock);
  1001.         ipc_answer_0(callid, rc);
  1002.         ipc_answer_0(rid, rc);
  1003.         return;
  1004.     }
  1005.     vfs_node_t *node = vfs_node_get(&lr);
  1006.     if (!node) {
  1007.         fibril_rwlock_read_unlock(&namespace_rwlock);
  1008.         ipc_answer_0(callid, ENOMEM);
  1009.         ipc_answer_0(rid, ENOMEM);
  1010.         return;
  1011.     }
  1012.  
  1013.     fibril_rwlock_read_unlock(&namespace_rwlock);
  1014.  
  1015.     int fs_phone = vfs_grab_phone(node->fs_handle);
  1016.     aid_t msg;
  1017.     msg = async_send_3(fs_phone, VFS_OUT_STAT, node->dev_handle,
  1018.         node->index, false, NULL);
  1019.     ipc_forward_fast(callid, fs_phone, 0, 0, 0, IPC_FF_ROUTE_FROM_ME);
  1020.    
  1021.     ipcarg_t rv;
  1022.     async_wait_for(msg, &rv);
  1023.     vfs_release_phone(fs_phone);
  1024.  
  1025.     ipc_answer_0(rid, rv);
  1026.  
  1027.     vfs_node_put(node);
  1028. }
  1029.  
  1030. void vfs_mkdir(ipc_callid_t rid, ipc_call_t *request)
  1031. {
  1032.     int mode = IPC_GET_ARG1(*request);
  1033.  
  1034.     size_t len;
  1035.     ipc_callid_t callid;
  1036.  
  1037.     if (!ipc_data_write_receive(&callid, &len)) {
  1038.         ipc_answer_0(callid, EINVAL);
  1039.         ipc_answer_0(rid, EINVAL);
  1040.         return;
  1041.     }
  1042.     char *path = malloc(len + 1);
  1043.     if (!path) {
  1044.         ipc_answer_0(callid, ENOMEM);
  1045.         ipc_answer_0(rid, ENOMEM);
  1046.         return;
  1047.     }
  1048.     int rc;
  1049.     if ((rc = ipc_data_write_finalize(callid, path, len))) {
  1050.         ipc_answer_0(rid, rc);
  1051.         free(path);
  1052.         return;
  1053.     }
  1054.     path[len] = '\0';
  1055.    
  1056.     fibril_rwlock_write_lock(&namespace_rwlock);
  1057.     int lflag = L_DIRECTORY | L_CREATE | L_EXCLUSIVE;
  1058.     rc = vfs_lookup_internal(path, lflag, NULL, NULL);
  1059.     fibril_rwlock_write_unlock(&namespace_rwlock);
  1060.     free(path);
  1061.     ipc_answer_0(rid, rc);
  1062. }
  1063.  
  1064. void vfs_unlink(ipc_callid_t rid, ipc_call_t *request)
  1065. {
  1066.     int lflag = IPC_GET_ARG1(*request);
  1067.  
  1068.     size_t len;
  1069.     ipc_callid_t callid;
  1070.  
  1071.     if (!ipc_data_write_receive(&callid, &len)) {
  1072.         ipc_answer_0(callid, EINVAL);
  1073.         ipc_answer_0(rid, EINVAL);
  1074.         return;
  1075.     }
  1076.     char *path = malloc(len + 1);
  1077.     if (!path) {
  1078.         ipc_answer_0(callid, ENOMEM);
  1079.         ipc_answer_0(rid, ENOMEM);
  1080.         return;
  1081.     }
  1082.     int rc;
  1083.     if ((rc = ipc_data_write_finalize(callid, path, len))) {
  1084.         ipc_answer_0(rid, rc);
  1085.         free(path);
  1086.         return;
  1087.     }
  1088.     path[len] = '\0';
  1089.    
  1090.     fibril_rwlock_write_lock(&namespace_rwlock);
  1091.     lflag &= L_DIRECTORY;   /* sanitize lflag */
  1092.     vfs_lookup_res_t lr;
  1093.     rc = vfs_lookup_internal(path, lflag | L_UNLINK, &lr, NULL);
  1094.     free(path);
  1095.     if (rc != EOK) {
  1096.         fibril_rwlock_write_unlock(&namespace_rwlock);
  1097.         ipc_answer_0(rid, rc);
  1098.         return;
  1099.     }
  1100.  
  1101.     /*
  1102.      * The name has already been unlinked by vfs_lookup_internal().
  1103.      * We have to get and put the VFS node to ensure that it is
  1104.      * VFS_OUT_DESTROY'ed after the last reference to it is dropped.
  1105.      */
  1106.     vfs_node_t *node = vfs_node_get(&lr);
  1107.     fibril_mutex_lock(&nodes_mutex);
  1108.     node->lnkcnt--;
  1109.     fibril_mutex_unlock(&nodes_mutex);
  1110.     fibril_rwlock_write_unlock(&namespace_rwlock);
  1111.     vfs_node_put(node);
  1112.     ipc_answer_0(rid, EOK);
  1113. }
  1114.  
  1115. void vfs_rename(ipc_callid_t rid, ipc_call_t *request)
  1116. {
  1117.     size_t olen, nlen;
  1118.     ipc_callid_t callid;
  1119.     int rc;
  1120.  
  1121.     /* Retrieve the old path. */
  1122.     if (!ipc_data_write_receive(&callid, &olen)) {
  1123.         ipc_answer_0(callid, EINVAL);
  1124.         ipc_answer_0(rid, EINVAL);
  1125.         return;
  1126.     }
  1127.     char *old = malloc(olen + 1);
  1128.     if (!old) {
  1129.         ipc_answer_0(callid, ENOMEM);
  1130.         ipc_answer_0(rid, ENOMEM);
  1131.         return;
  1132.     }
  1133.     if ((rc = ipc_data_write_finalize(callid, old, olen))) {
  1134.         ipc_answer_0(rid, rc);
  1135.         free(old);
  1136.         return;
  1137.     }
  1138.     old[olen] = '\0';
  1139.    
  1140.     /* Retrieve the new path. */
  1141.     if (!ipc_data_write_receive(&callid, &nlen)) {
  1142.         ipc_answer_0(callid, EINVAL);
  1143.         ipc_answer_0(rid, EINVAL);
  1144.         free(old);
  1145.         return;
  1146.     }
  1147.     char *new = malloc(nlen + 1);
  1148.     if (!new) {
  1149.         ipc_answer_0(callid, ENOMEM);
  1150.         ipc_answer_0(rid, ENOMEM);
  1151.         free(old);
  1152.         return;
  1153.     }
  1154.     if ((rc = ipc_data_write_finalize(callid, new, nlen))) {
  1155.         ipc_answer_0(rid, rc);
  1156.         free(old);
  1157.         free(new);
  1158.         return;
  1159.     }
  1160.     new[nlen] = '\0';
  1161.  
  1162.     char *oldc = canonify(old, &olen);
  1163.     char *newc = canonify(new, &nlen);
  1164.     if (!oldc || !newc) {
  1165.         ipc_answer_0(rid, EINVAL);
  1166.         free(old);
  1167.         free(new);
  1168.         return;
  1169.     }
  1170.     oldc[olen] = '\0';
  1171.     newc[nlen] = '\0';
  1172.     if ((!str_lcmp(newc, oldc, str_length(oldc))) &&
  1173.         ((newc[str_length(oldc)] == '/') ||
  1174.         (str_length(oldc) == 1) ||
  1175.         (str_length(oldc) == str_length(newc)))) {
  1176.             /*
  1177.          * oldc is a prefix of newc and either
  1178.          * - newc continues with a / where oldc ends, or
  1179.          * - oldc was / itself, or
  1180.          * - oldc and newc are equal.
  1181.          */
  1182.         ipc_answer_0(rid, EINVAL);
  1183.         free(old);
  1184.         free(new);
  1185.         return;
  1186.     }
  1187.    
  1188.     vfs_lookup_res_t old_lr;
  1189.     vfs_lookup_res_t new_lr;
  1190.     vfs_lookup_res_t new_par_lr;
  1191.     fibril_rwlock_write_lock(&namespace_rwlock);
  1192.     /* Lookup the node belonging to the old file name. */
  1193.     rc = vfs_lookup_internal(oldc, L_NONE, &old_lr, NULL);
  1194.     if (rc != EOK) {
  1195.         fibril_rwlock_write_unlock(&namespace_rwlock);
  1196.         ipc_answer_0(rid, rc);
  1197.         free(old);
  1198.         free(new);
  1199.         return;
  1200.     }
  1201.     vfs_node_t *old_node = vfs_node_get(&old_lr);
  1202.     if (!old_node) {
  1203.         fibril_rwlock_write_unlock(&namespace_rwlock);
  1204.         ipc_answer_0(rid, ENOMEM);
  1205.         free(old);
  1206.         free(new);
  1207.         return;
  1208.     }
  1209.     /* Determine the path to the parent of the node with the new name. */
  1210.     char *parentc = str_dup(newc);
  1211.     if (!parentc) {
  1212.         fibril_rwlock_write_unlock(&namespace_rwlock);
  1213.         ipc_answer_0(rid, rc);
  1214.         free(old);
  1215.         free(new);
  1216.         return;
  1217.     }
  1218.     char *lastsl = str_rchr(parentc + 1, '/');
  1219.     if (lastsl)
  1220.         *lastsl = '\0';
  1221.     else
  1222.         parentc[1] = '\0';
  1223.     /* Lookup parent of the new file name. */
  1224.     rc = vfs_lookup_internal(parentc, L_NONE, &new_par_lr, NULL);
  1225.     free(parentc);  /* not needed anymore */
  1226.     if (rc != EOK) {
  1227.         fibril_rwlock_write_unlock(&namespace_rwlock);
  1228.         ipc_answer_0(rid, rc);
  1229.         free(old);
  1230.         free(new);
  1231.         return;
  1232.     }
  1233.     /* Check whether linking to the same file system instance. */
  1234.     if ((old_node->fs_handle != new_par_lr.triplet.fs_handle) ||
  1235.         (old_node->dev_handle != new_par_lr.triplet.dev_handle)) {
  1236.         fibril_rwlock_write_unlock(&namespace_rwlock);
  1237.         ipc_answer_0(rid, EXDEV);   /* different file systems */
  1238.         free(old);
  1239.         free(new);
  1240.         return;
  1241.     }
  1242.     /* Destroy the old link for the new name. */
  1243.     vfs_node_t *new_node = NULL;
  1244.     rc = vfs_lookup_internal(newc, L_UNLINK, &new_lr, NULL);
  1245.     switch (rc) {
  1246.     case ENOENT:
  1247.         /* simply not in our way */
  1248.         break;
  1249.     case EOK:
  1250.         new_node = vfs_node_get(&new_lr);
  1251.         if (!new_node) {
  1252.             fibril_rwlock_write_unlock(&namespace_rwlock);
  1253.             ipc_answer_0(rid, ENOMEM);
  1254.             free(old);
  1255.             free(new);
  1256.             return;
  1257.         }
  1258.         fibril_mutex_lock(&nodes_mutex);
  1259.         new_node->lnkcnt--;
  1260.         fibril_mutex_unlock(&nodes_mutex);
  1261.         break;
  1262.     default:
  1263.         fibril_rwlock_write_unlock(&namespace_rwlock);
  1264.         ipc_answer_0(rid, ENOTEMPTY);
  1265.         free(old);
  1266.         free(new);
  1267.         return;
  1268.     }
  1269.     /* Create the new link for the new name. */
  1270.     rc = vfs_lookup_internal(newc, L_LINK, NULL, NULL, old_node->index);
  1271.     if (rc != EOK) {
  1272.         fibril_rwlock_write_unlock(&namespace_rwlock);
  1273.         if (new_node)
  1274.             vfs_node_put(new_node);
  1275.         ipc_answer_0(rid, rc);
  1276.         free(old);
  1277.         free(new);
  1278.         return;
  1279.     }
  1280.     fibril_mutex_lock(&nodes_mutex);
  1281.     old_node->lnkcnt++;
  1282.     fibril_mutex_unlock(&nodes_mutex);
  1283.     /* Destroy the link for the old name. */
  1284.     rc = vfs_lookup_internal(oldc, L_UNLINK, NULL, NULL);
  1285.     if (rc != EOK) {
  1286.         fibril_rwlock_write_unlock(&namespace_rwlock);
  1287.         vfs_node_put(old_node);
  1288.         if (new_node)
  1289.             vfs_node_put(new_node);
  1290.         ipc_answer_0(rid, rc);
  1291.         free(old);
  1292.         free(new);
  1293.         return;
  1294.     }
  1295.     fibril_mutex_lock(&nodes_mutex);
  1296.     old_node->lnkcnt--;
  1297.     fibril_mutex_unlock(&nodes_mutex);
  1298.     fibril_rwlock_write_unlock(&namespace_rwlock);
  1299.     vfs_node_put(old_node);
  1300.     if (new_node)
  1301.         vfs_node_put(new_node);
  1302.     free(old);
  1303.     free(new);
  1304.     ipc_answer_0(rid, EOK);
  1305. }
  1306.  
  1307. /**
  1308.  * @}
  1309.  */
  1310.