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>
 #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
 /*
  * Hash table of all directory entries.
  */
 hash_table_t dentries;
 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 *) malloc(sizeof(tmpfs_dentry_t));
     if (!root)
         return false;
     tmpfs_dentry_initialize(root);
     root->index = tmpfs_next_index++;
     root->name = "";
     root->type = TMPFS_DIRECTORY;
     hash_table_insert(&dentries, &root->index, &root->dh_link);
     /*
      * This is only for debugging. Once we can create files and directories
      * using VFS, we can get rid of this.
      */
     tmpfs_dentry_t *d;
     d = (tmpfs_dentry_t *) malloc(sizeof(tmpfs_dentry_t));
     if (!d) {
         free(root);
         root = NULL;
         return false;
+    }
     tmpfs_dentry_initialize(d);
     d->index = tmpfs_next_index++;
     root->child = d;
     d->parent = root;
     d->type = TMPFS_DIRECTORY;
     d->name = "dir1";
     hash_table_insert(&dentries, &d->index, &d->dh_link);
     d = (tmpfs_dentry_t *) malloc(sizeof(tmpfs_dentry_t));
     if (!d) {
         free(root->child);
         free(root);
         root = NULL;
         return false;
+    }
     tmpfs_dentry_initialize(d);
     d->index = tmpfs_next_index++;
     root->child->sibling = d;
     d->parent = root;
     d->type = TMPFS_DIRECTORY;
     d->name = "dir2";
     hash_table_insert(&dentries, &d->index, &d->dh_link);
     d = (tmpfs_dentry_t *) malloc(sizeof(tmpfs_dentry_t));
     if (!d) {
         free(root->child->sibling);
         free(root->child);
         free(root);
         root = NULL;
         return false;
+    }
     tmpfs_dentry_initialize(d);
     d->index = tmpfs_next_index++;
     root->child->child = d;
     d->parent = root->child;
     d->type = TMPFS_FILE;
     d->name = "file1";
     d->data = "This is the contents of /dir1/file1.\n";
     d->size = strlen(d->data);
     hash_table_insert(&dentries, &d->index, &d->dh_link);
     d = (tmpfs_dentry_t *) malloc(sizeof(tmpfs_dentry_t));
     if (!d) {
         free(root->child->sibling);
         free(root->child->child);
         free(root->child);
         free(root);
         root = NULL;
         return false;
+    }
     tmpfs_dentry_initialize(d);
     d->index = tmpfs_next_index++;
     root->child->sibling->child = d;
     d->parent = root->child->sibling;
     d->type = TMPFS_FILE;
     d->name = "file2";
     d->data = "This is the contents of /dir2/file2.\n";
     d->size = strlen(d->data);
     hash_table_insert(&dentries, &d->index, &d->dh_link);
     return true;
+}
 /** Compare one component of path to a directory entry.
+ *
  * @param dentry    Directory entry to compare the path component with.
- * @param start     Index into PLB where the path component starts.
+ * @param component Array of characters holding component name.
- * @param last      Index of the last character of the path in PLB.
+ *
- * @return      Zero on failure or delta such that (index + delta) %
+ * @return      True on match, false otherwise.
- *          PLB_SIZE points to the first unprocessed character in
- *          PLB which comprises the path.
  */
-static unsigned match_path_component(tmpfs_dentry_t *dentry, unsigned start,
+static bool match_component(tmpfs_dentry_t *dentry, const char *component)
-    unsigned last)
+{
-    int i, j;
-    size_t namelen;
+    return !strcmp(dentry->name, component);
+}
-    namelen = strlen(dentry->name);
+static unsigned long create_node(tmpfs_dentry_t *dentry,
-    if (last < start)
+    const char *component, int lflag)
+{
-        last += PLB_SIZE;
+    return 0;
+}
-    for (i = 0, j = start; i < namelen && j <= last; i++, j++) {
-        if (dentry->name[i] != PLB_GET_CHAR(j))
+static int destroy_component(tmpfs_dentry_t *dentry)
-            return 0;
-    }
+{
-    if (i != namelen)
-        return 0;
-    if (j < last && PLB_GET_CHAR(j) != '/')
-        return 0;
+    return EPERM;
-    if (j == last)
-            return 0;
-    return (j - start);
+}
 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.
+     */
     if (!root && !tmpfs_init()) {
         ipc_answer_0(rid, ENOMEM);
         return;
+    }
     tmpfs_dentry_t *dtmp = root->child;
     tmpfs_dentry_t *dcur = root;
-    bool hit = true;
     if (PLB_GET_CHAR(next) == '/')
         next++;     /* eat slash */
+    char component[NAME_MAX + 1];
+    int len = 0;
     while (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 */
-        unsigned delta;
+            if (next <= last)
-        hit = false;
+                continue;
-        do {
+        }
+        assert(len);
+        component[len] = '\0';
+        next++;     /* eat slash */
+        len = 0;
+        /* match the component */
-            delta = match_path_component(dtmp, next, last);
+        while (dtmp && !match_component(dtmp, component))
+            dtmp = dtmp->sibling;
+        /* handle miss: match amongst siblings */
-            if (!delta) {
+        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;
+                }
+                unsigned long index = create_node(dcur,
-                dtmp = dtmp->sibling;
+                    component, lflag);
+                if (index) {
+                    ipc_answer_4(rid, EOK,
+                        tmpfs_reg.fs_handle, dev_handle,
+                        index, 0);
-            } else {
+                } else {
+                    ipc_answer_0(rid, ENOSPC);
+                }
-                hit = true;
+                return;
+            }
+            ipc_answer_0(rid, ENOENT);
-                next += delta;
+            return;
+        }
-                next++;     /* eat slash */
+        /* descent one level */
-                dcur = dtmp;
+        dcur = dtmp;
-                dtmp = dtmp->child;
+        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 (delta == 0 && dtmp);
+                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;
+                unsigned long index;
+                index = create_node(dcur, component, lflag);
-        if (!hit) {
+                if (index) {
-            ipc_answer_3(rid, ENOENT, tmpfs_reg.fs_handle,
+                    ipc_answer_4(rid, EOK,
-                dev_handle, dcur->index);
+                        tmpfs_reg.fs_handle, dev_handle,
+                        index, 0);
+                } else {
+                    ipc_answer_0(rid, ENOSPC);
+                }
+                return;
+            }
+            ipc_answer_0(rid, ENOENT);
             return;
+        }
+    }
+    /* handle hit */
+    if (lflag & L_DESTROY) {
+        int res = destroy_component(dcur);
+        ipc_answer_0(rid, res);
+        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_4(rid, EOK, tmpfs_reg.fs_handle, dev_handle, dcur->index,
         dcur->size);
+}
 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 = dentry->child;
         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_1(rid, EOK, len);
         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_1(rid, EOK, 0);
         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);
+}
 /**
  * @}
  */

Subversion Repositories HelenOS

(root)/branches/network/uspace/srv/fs/tmpfs/tmpfs_ops.c @ 4718 – Rev 2700 → 2705