WebSVN – HelenOS – Diff – /branches/network/uspace/srv/fs/tmpfs/tmpfs_ops.c

 /*
  * Copyright (c) 2008 Jakub Jermar
  * All rights reserved.
+ *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
+ *
  * - Redistributions of source code must retain the above copyright
  *   notice, this list of conditions and the following disclaimer.
  * - Redistributions in binary form must reproduce the above copyright
  *   notice, this list of conditions and the following disclaimer in the
  *   documentation and/or other materials provided with the distribution.
  * - The name of the author may not be used to endorse or promote products
  *   derived from this software without specific prior written permission.
+ *
  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 /** @addtogroup fs
  * @{
  */
 /**
  * @file    tmpfs_ops.c
  * @brief   Implementation of VFS operations for the TMPFS file system
  *      server.
  */
 #include "tmpfs.h"
 #include "../../vfs/vfs.h"
 #include <ipc/ipc.h>
 #include <async.h>
 #include <errno.h>
 #include <atomic.h>
 #include <stdlib.h>
 #include <string.h>
 #include <stdio.h>
-#include <dirent.h>
 #include <assert.h>
 #include <sys/types.h>
 #include <libadt/hash_table.h>
 #include <as.h>
+#include <libfs.h>
 #define min(a, b)       ((a) < (b) ? (a) : (b))
 #define max(a, b)       ((a) > (b) ? (a) : (b))
-#define PLB_GET_CHAR(i)     (tmpfs_reg.plb_ro[(i) % PLB_SIZE])
 #define DENTRIES_BUCKETS    256
+/*
-#define TMPFS_GET_INDEX(x)  (((tmpfs_dentry_t *)(x))->index)
+ * For now, we don't distinguish between different dev_handles/instances. All
+ * requests resolve to the only instance, rooted in the following variable.
+ */
-#define TMPFS_GET_LNKCNT(x) 1
+static tmpfs_dentry_t *root;
+/*
+ * Implementation of the libfs interface.
+ */
 /* Forward declarations of static functions. */
+static bool tmpfs_match(void *, const char *);
-static void *create_node(int);
+static void *tmpfs_create_node(int);
-static bool link_node(void *, void *, const char *);
+static bool tmpfs_link_node(void *, void *, const char *);
-static int unlink_node(void *);
+static int tmpfs_unlink_node(void *);
-static void destroy_node(void *);
+static void tmpfs_destroy_node(void *);
+/* Implementation of helper functions. */
+static unsigned long tmpfs_index_get(void *nodep)
+{
+    return ((tmpfs_dentry_t *) nodep)->index;
+}
+static unsigned long tmpfs_size_get(void *nodep)
+{
+    return ((tmpfs_dentry_t *) nodep)->size;
+}
+static unsigned tmpfs_lnkcnt_get(void *nodep)
+{
+    return 1;
+}
+static void *tmpfs_child_get(void *nodep)
+{
+    return ((tmpfs_dentry_t *) nodep)->child;
+}
+static void *tmpfs_sibling_get(void *nodep)
+{
+    return ((tmpfs_dentry_t *) nodep)->sibling;
+}
+static void *tmpfs_root_get(void)
+{
+    return root;
+}
+static char tmpfs_plb_get_char(unsigned pos)
+{
+    return tmpfs_reg.plb_ro[pos % PLB_SIZE];
+}
+static bool tmpfs_is_directory(void *nodep)
+{
+    return ((tmpfs_dentry_t *) nodep)->type == TMPFS_DIRECTORY;
+}
+static bool tmpfs_is_file(void *nodep)
+{
+    return ((tmpfs_dentry_t *) nodep)->type == TMPFS_FILE;
+}
+/** libfs operations */
+libfs_ops_t tmpfs_libfs_ops = {
+    .match = tmpfs_match,
+    .create = tmpfs_create_node,
+    .destroy = tmpfs_destroy_node,
+    .link = tmpfs_link_node,
+    .unlink = tmpfs_unlink_node,
+    .index_get = tmpfs_index_get,
+    .size_get = tmpfs_size_get,
+    .lnkcnt_get = tmpfs_lnkcnt_get,
+    .child_get = tmpfs_child_get,
+    .sibling_get = tmpfs_sibling_get,
+    .root_get = tmpfs_root_get,
+    .plb_get_char = tmpfs_plb_get_char,
+    .is_directory = tmpfs_is_directory,
+    .is_file = tmpfs_is_file
+};
 /** Hash table of all directory entries. */
 hash_table_t dentries;
+/* Implementation of hash table interface. */
 static hash_index_t dentries_hash(unsigned long *key)
+{
     return *key % DENTRIES_BUCKETS;
+}
 static int dentries_compare(unsigned long *key, hash_count_t keys,
     link_t *item)
+{
     tmpfs_dentry_t *dentry = hash_table_get_instance(item, tmpfs_dentry_t,
         dh_link);
     return dentry->index == *key;
+}
 static void dentries_remove_callback(link_t *item)
+{
+}
 /** TMPFS dentries hash table operations. */
 hash_table_operations_t dentries_ops = {
     .hash = dentries_hash,
     .compare = dentries_compare,
     .remove_callback = dentries_remove_callback
 };
 unsigned tmpfs_next_index = 1;
 static void tmpfs_dentry_initialize(tmpfs_dentry_t *dentry)
+{
     dentry->index = 0;
     dentry->parent = NULL;
     dentry->sibling = NULL;
     dentry->child = NULL;
     dentry->name = NULL;
     dentry->type = TMPFS_NONE;
     dentry->size = 0;
     dentry->data = NULL;
     link_initialize(&dentry->dh_link);
+}
-/*
- * For now, we don't distinguish between different dev_handles/instances. All
- * requests resolve to the only instance, rooted in the following variable.
- */
-static tmpfs_dentry_t *root;
 static bool tmpfs_init(void)
+{
     if (!hash_table_create(&dentries, DENTRIES_BUCKETS, 1, &dentries_ops))
         return false;
-    root = (tmpfs_dentry_t *) create_node(L_DIRECTORY);
+    root = (tmpfs_dentry_t *) tmpfs_create_node(L_DIRECTORY);
     return root != NULL;
+}
 /** Compare one component of path to a directory entry.
+ *
  * @param nodep     Node to compare the path component with.
  * @param component Array of characters holding component name.
+ *
  * @return      True on match, false otherwise.
  */
-static bool match_component(void *nodep, const char *component)
+bool tmpfs_match(void *nodep, const char *component)
+{
     tmpfs_dentry_t *dentry = (tmpfs_dentry_t *) nodep;
     return !strcmp(dentry->name, component);
+}
-void *create_node(int lflag)
+void *tmpfs_create_node(int lflag)
+{
     assert((lflag & L_FILE) ^ (lflag & L_DIRECTORY));
     tmpfs_dentry_t *node = malloc(sizeof(tmpfs_dentry_t));
     if (!node)
         return NULL;
     tmpfs_dentry_initialize(node);
     node->index = tmpfs_next_index++;
     if (lflag & L_DIRECTORY)
         node->type = TMPFS_DIRECTORY;
     else
         node->type = TMPFS_FILE;
     /* Insert the new node into the dentry hash table. */
     hash_table_insert(&dentries, &node->index, &node->dh_link);
     return (void *) node;
+}
-bool link_node(void *prnt, void *chld, const char *nm)
+bool tmpfs_link_node(void *prnt, void *chld, const char *nm)
+{
     tmpfs_dentry_t *parentp = (tmpfs_dentry_t *) prnt;
     tmpfs_dentry_t *childp = (tmpfs_dentry_t *) chld;
     assert(parentp->type == TMPFS_DIRECTORY);
     size_t len = strlen(nm);
     char *name = malloc(len + 1);
     if (!name)
         return false;
     strcpy(name, nm);
     childp->name = name;
     /* Insert the new node into the namespace. */
     if (parentp->child) {
         tmpfs_dentry_t *tmp = parentp->child;
         while (tmp->sibling)
             tmp = tmp->sibling;
         tmp->sibling = childp;
     } else {
         parentp->child = childp;
+    }
     childp->parent = parentp;
     return true;
+}
-int unlink_node(void *nodeptr)
+int tmpfs_unlink_node(void *nodeptr)
+{
     tmpfs_dentry_t *dentry = (tmpfs_dentry_t *)nodeptr;
     if (dentry->child)
         return ENOTEMPTY;
     if (!dentry->parent)
         return EBUSY;
     if (dentry->parent->child == dentry) {
         dentry->parent->child = dentry->sibling;
     } else {
         /* TODO: consider doubly linked list for organizing siblings. */
         tmpfs_dentry_t *tmp = dentry->parent->child;
         while (tmp->sibling != dentry)
             tmp = tmp->sibling;
         tmp->sibling = dentry->sibling;
+    }
     dentry->sibling = NULL;
     dentry->parent = NULL;
     free(dentry->name);
     dentry->name = NULL;
     return EOK;
+}
-void destroy_node(void *nodep)
+void tmpfs_destroy_node(void *nodep)
+{
     tmpfs_dentry_t *dentry = (tmpfs_dentry_t *) nodep;
     assert(!dentry->child);
     assert(!dentry->sibling);
     unsigned long index = dentry->index;
     hash_table_remove(&dentries, &index, 1);
     if (dentry->type == TMPFS_FILE)
         free(dentry->data);
     free(dentry);
+}
 void tmpfs_lookup(ipc_callid_t rid, ipc_call_t *request)
+{
-    unsigned next = IPC_GET_ARG1(*request);
-    unsigned last = IPC_GET_ARG2(*request);
-    int dev_handle = IPC_GET_ARG3(*request);
-    int lflag = IPC_GET_ARG4(*request);
-    if (last < next)
-        last += PLB_SIZE;
-    /*
-     * Initialize TMPFS.
+    /* Initialize TMPFS. */
-     */
     if (!root && !tmpfs_init()) {
         ipc_answer_0(rid, ENOMEM);
         return;
+    }
-    tmpfs_dentry_t *dtmp = root->child;
-    tmpfs_dentry_t *dcur = root;
-    if (PLB_GET_CHAR(next) == '/')
-        next++;     /* eat slash */
-    char component[NAME_MAX + 1];
-    int len = 0;
-    while (dtmp && next <= last) {
-        /* collect the component */
-        if (PLB_GET_CHAR(next) != '/') {
-            if (len + 1 == NAME_MAX) {
-                /* comopnent length overflow */
-                ipc_answer_0(rid, ENAMETOOLONG);
-                return;
-            }
-            component[len++] = PLB_GET_CHAR(next);
-            next++; /* process next character */
-            if (next <= last)
-                continue;
-        }
-        assert(len);
-        component[len] = '\0';
-        next++;     /* eat slash */
-        len = 0;
-        /* match the component */
-        while (dtmp && !match_component(dtmp, component))
-            dtmp = dtmp->sibling;
-        /* handle miss: match amongst siblings */
-        if (!dtmp) {
-            if ((next > last) && (lflag & L_CREATE)) {
-                /* no components left and L_CREATE specified */
-                if (dcur->type != TMPFS_DIRECTORY) {
-                    ipc_answer_0(rid, ENOTDIR);
-                    return;
-                }
-                void *nodep = create_node(lflag);
-                if (nodep) {
-                    if (!link_node(dcur, nodep,
-                        component)) {
-                        destroy_node(nodep);
-                        ipc_answer_0(rid, ENOSPC);
-                    } else {
-                        ipc_answer_5(rid, EOK,
-                            tmpfs_reg.fs_handle,
-                            dev_handle,
-                            TMPFS_GET_INDEX(nodep), 0,
-                            TMPFS_GET_LNKCNT(nodep));
-                    }
-                } else {
-                    ipc_answer_0(rid, ENOSPC);
-                }
-                return;
-            }
-            ipc_answer_0(rid, ENOENT);
-            return;
-        }
-        /* descend one level */
-        dcur = dtmp;
-        dtmp = dtmp->child;
-    }
-    /* handle miss: excessive components */
-    if (!dtmp && next <= last) {
-        if (lflag & L_CREATE) {
-            if (dcur->type != TMPFS_DIRECTORY) {
-                ipc_answer_0(rid, ENOTDIR);
-                return;
-            }
-            /* collect next component */
-            while (next <= last) {
-                if (PLB_GET_CHAR(next) == '/') {
-                    /* more than one component */
-                    ipc_answer_0(rid, ENOENT);
-                    return;
-                }
-                if (len + 1 == NAME_MAX) {
-                    /* component length overflow */
-                    ipc_answer_0(rid, ENAMETOOLONG);
-                    return;
-                }
-                component[len++] = PLB_GET_CHAR(next);
-                next++; /* process next character */
-            }
-            assert(len);
-            component[len] = '\0';
-            len = 0;
-            void *nodep = create_node(lflag);
-            if (nodep) {
-                if (!link_node(dcur, nodep, component)) {
-                    destroy_node(nodep);
-                    ipc_answer_0(rid, ENOSPC);
-                } else {
-                    ipc_answer_5(rid, EOK,
-                        tmpfs_reg.fs_handle,
-                        dev_handle, TMPFS_GET_INDEX(nodep),
-, TMPFS_GET_LNKCNT(nodep));
-                }
-            } else {
-                ipc_answer_0(rid, ENOSPC);
-            }
-            return;
-        }
-        ipc_answer_0(rid, ENOENT);
-        return;
-    }
-    /* handle hit */
-    if (lflag & L_DESTROY) {
-        unsigned old_lnkcnt = TMPFS_GET_LNKCNT(dcur);
-        int res = unlink_node(dcur);
-        ipc_answer_5(rid, (ipcarg_t)res, tmpfs_reg.fs_handle,
-            dev_handle, dcur->index, dcur->size, old_lnkcnt);
-        return;
-    }
-    if ((lflag & (L_CREATE | L_EXCLUSIVE)) == (L_CREATE | L_EXCLUSIVE)) {
-        ipc_answer_0(rid, EEXIST);
-        return;
-    }
-    if ((lflag & L_FILE) && (dcur->type != TMPFS_FILE)) {
-        ipc_answer_0(rid, EISDIR);
-        return;
-    }
-    if ((lflag & L_DIRECTORY) && (dcur->type != TMPFS_DIRECTORY)) {
-        ipc_answer_0(rid, ENOTDIR);
-        return;
-    }
-    ipc_answer_5(rid, EOK, tmpfs_reg.fs_handle, dev_handle, dcur->index,
+    libfs_lookup(&tmpfs_libfs_ops, tmpfs_reg.fs_handle, rid, request);
-        dcur->size, TMPFS_GET_LNKCNT(dcur));
+}
 void tmpfs_read(ipc_callid_t rid, ipc_call_t *request)
+{
     int dev_handle = IPC_GET_ARG1(*request);
     unsigned long index = IPC_GET_ARG2(*request);
     off_t pos = IPC_GET_ARG3(*request);
     /*
      * Lookup the respective dentry.
      */
     link_t *hlp;
     hlp = hash_table_find(&dentries, &index);
     if (!hlp) {
         ipc_answer_0(rid, ENOENT);
         return;
+    }
     tmpfs_dentry_t *dentry = hash_table_get_instance(hlp, tmpfs_dentry_t,
         dh_link);
     /*
      * Receive the read request.
      */
     ipc_callid_t callid;
     size_t len;
     if (!ipc_data_read_receive(&callid, &len)) {
         ipc_answer_0(callid, EINVAL);
         ipc_answer_0(rid, EINVAL);
         return;
+    }
     size_t bytes;
     if (dentry->type == TMPFS_FILE) {
         bytes = max(0, min(dentry->size - pos, len));
         (void) ipc_data_read_finalize(callid, dentry->data + pos,
             bytes);
     } else {
         int i;
         tmpfs_dentry_t *cur;
         assert(dentry->type == TMPFS_DIRECTORY);
         /*
          * Yes, we really use O(n) algorithm here.
          * If it bothers someone, it could be fixed by introducing a
          * hash table.
          */
         for (i = 0, cur = dentry->child; i < pos && cur; i++,
             cur = cur->sibling)
+            ;
         if (!cur) {
             ipc_answer_0(callid, ENOENT);
             ipc_answer_1(rid, ENOENT, 0);
             return;
+        }
         (void) ipc_data_read_finalize(callid, cur->name,
             strlen(cur->name) + 1);
         bytes = 1;
+    }
     /*
      * Answer the VFS_READ call.
      */
     ipc_answer_1(rid, EOK, bytes);
+}
 void tmpfs_write(ipc_callid_t rid, ipc_call_t *request)
+{
     int dev_handle = IPC_GET_ARG1(*request);
     unsigned long index = IPC_GET_ARG2(*request);
     off_t pos = IPC_GET_ARG3(*request);
     /*
      * Lookup the respective dentry.
      */
     link_t *hlp;
     hlp = hash_table_find(&dentries, &index);
     if (!hlp) {
         ipc_answer_0(rid, ENOENT);
         return;
+    }
     tmpfs_dentry_t *dentry = hash_table_get_instance(hlp, tmpfs_dentry_t,
         dh_link);
     /*
      * Receive the write request.
      */
     ipc_callid_t callid;
     size_t len;
     if (!ipc_data_write_receive(&callid, &len)) {
         ipc_answer_0(callid, EINVAL);
         ipc_answer_0(rid, EINVAL);
         return;
+    }
     /*
      * Check whether the file needs to grow.
      */
     if (pos + len <= dentry->size) {
         /* The file size is not changing. */
         (void) ipc_data_write_finalize(callid, dentry->data + pos, len);
         ipc_answer_2(rid, EOK, len, dentry->size);
         return;
+    }
     size_t delta = (pos + len) - dentry->size;
     /*
      * At this point, we are deliberately extremely straightforward and
      * simply realloc the contents of the file on every write that grows the
      * file. In the end, the situation might not be as bad as it may look:
      * our heap allocator can save us and just grow the block whenever
      * possible.
      */
     void *newdata = realloc(dentry->data, dentry->size + delta);
     if (!newdata) {
         ipc_answer_0(callid, ENOMEM);
         ipc_answer_2(rid, EOK, 0, dentry->size);
         return;
+    }
     /* Clear any newly allocated memory in order to emulate gaps. */
     memset(newdata + dentry->size, 0, delta);
     dentry->size += delta;
     dentry->data = newdata;
     (void) ipc_data_write_finalize(callid, dentry->data + pos, len);
     ipc_answer_2(rid, EOK, len, dentry->size);
+}
 void tmpfs_truncate(ipc_callid_t rid, ipc_call_t *request)
+{
     int dev_handle = IPC_GET_ARG1(*request);
     unsigned long index = IPC_GET_ARG2(*request);
     size_t size = IPC_GET_ARG3(*request);
     /*
      * Lookup the respective dentry.
      */
     link_t *hlp;
     hlp = hash_table_find(&dentries, &index);
     if (!hlp) {
         ipc_answer_0(rid, ENOENT);
         return;
+    }
     tmpfs_dentry_t *dentry = hash_table_get_instance(hlp, tmpfs_dentry_t,
         dh_link);
     if (size == dentry->size) {
         ipc_answer_0(rid, EOK);
         return;
+    }
     void *newdata = realloc(dentry->data, size);
     if (!newdata) {
         ipc_answer_0(rid, ENOMEM);
         return;
+    }
     if (size > dentry->size) {
         size_t delta = size - dentry->size;
         memset(newdata + dentry->size, 0, delta);
+    }
     dentry->size = size;
     dentry->data = newdata;
     ipc_answer_0(rid, EOK);
+}
 void tmpfs_destroy(ipc_callid_t rid, ipc_call_t *request)
+{
     int dev_handle = IPC_GET_ARG1(*request);
     unsigned long index = IPC_GET_ARG2(*request);
     link_t *hlp;
     hlp = hash_table_find(&dentries, &index);
     if (!hlp) {
         ipc_answer_0(rid, ENOENT);
         return;
+    }
     tmpfs_dentry_t *dentry = hash_table_get_instance(hlp, tmpfs_dentry_t,
         dh_link);
-    destroy_node(dentry);
+    tmpfs_destroy_node(dentry);
     ipc_answer_0(rid, EOK);
+}
 /**
  * @}
  */

Subversion Repositories HelenOS

(root)/branches/network/uspace/srv/fs/tmpfs/tmpfs_ops.c @ 4718 – Rev 2742 → 2747