source: mainline/kernel/generic/src/sysinfo/sysinfo.c@ da1bafb

/*
 * Copyright (c) 2006 Jakub Vana
 * 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 generic
 * @{
 */
/** @file
 */

#include <sysinfo/sysinfo.h>
#include <mm/slab.h>
#include <print.h>
#include <syscall/copy.h>
#include <synch/mutex.h>
#include <arch/asm.h>
#include <errno.h>

/** Maximal sysinfo path length */
#define SYSINFO_MAX_PATH  2048

bool fb_exported = false;

/** Global sysinfo tree root item */
static sysinfo_item_t *global_root = NULL;

/** Sysinfo SLAB cache */
static slab_cache_t *sysinfo_item_slab;

/** Sysinfo lock */
static mutex_t sysinfo_lock;

/** Sysinfo item constructor
 *
 */
static int sysinfo_item_constructor(void *obj, unsigned int kmflag)
{
        sysinfo_item_t *item = (sysinfo_item_t *) obj;
        
        item->name = NULL;
        item->val_type = SYSINFO_VAL_UNDEFINED;
        item->subtree_type = SYSINFO_SUBTREE_NONE;
        item->subtree.table = NULL;
        item->next = NULL;
        
        return 0;
}

/** Sysinfo item destructor
 *
 * Note that the return value is not perfectly correct
 * since more space might get actually freed thanks
 * to the disposal of item->name
 *
 */
static size_t sysinfo_item_destructor(void *obj)
{
        sysinfo_item_t *item = (sysinfo_item_t *) obj;
        
        if (item->name != NULL)
                free(item->name);
        
        return 0;
}

/** Initialize sysinfo subsystem
 *
 * Create SLAB cache for sysinfo items.
 *
 */
void sysinfo_init(void)
{
        sysinfo_item_slab = slab_cache_create("sysinfo_item_slab",
            sizeof(sysinfo_item_t), 0, sysinfo_item_constructor,
            sysinfo_item_destructor, SLAB_CACHE_MAGDEFERRED);

        mutex_initialize(&sysinfo_lock, MUTEX_ACTIVE);
}

/** Recursively find an item in sysinfo tree
 *
 * Should be called with sysinfo_lock held.
 *
 * @param name    Current sysinfo path suffix.
 * @param subtree Current sysinfo (sub)tree root item.
 * @param ret     If the return value is NULL, this argument
 *                can be either also NULL (i.e. no item was
 *                found and no data was generated) or the
 *                original pointer is used to store the value
 *                generated by a generated subtree function.
 * @param dry_run Do not actually get any generated
 *                binary data, just calculate the size.
 *
 * @return Found item or NULL if no item in the fixed tree
 *         was found (N.B. ret).
 *
 */
static sysinfo_item_t *sysinfo_find_item(const char *name,
    sysinfo_item_t *subtree, sysinfo_return_t **ret, bool dry_run)
{
        ASSERT(subtree != NULL);
        ASSERT(ret != NULL);
        
        sysinfo_item_t *cur = subtree;
        
        /* Walk all siblings */
        while (cur != NULL) {
                size_t i = 0;
                
                /* Compare name with path */
                while ((cur->name[i] != 0) && (name[i] == cur->name[i]))
                        i++;
                
                /* Check for perfect name and path match */
                if ((name[i] == 0) && (cur->name[i] == 0))
                        return cur;
                
                /* Partial match up to the delimiter */
                if ((name[i] == '.') && (cur->name[i] == 0)) {
                        /* Look into the subtree */
                        switch (cur->subtree_type) {
                        case SYSINFO_SUBTREE_TABLE:
                                /* Recursively find in subtree */
                                return sysinfo_find_item(name + i + 1,
                                    cur->subtree.table, ret, dry_run);
                        case SYSINFO_SUBTREE_FUNCTION:
                                /* Get generated data */
                                **ret = cur->subtree.get_data(name + i + 1, dry_run);
                                return NULL;
                        default:
                                /* Not found, no data generated */
                                *ret = NULL;
                                return NULL;
                        }
                }
                
                cur = cur->next;
        }
        
        /* Not found, no data generated */
        *ret = NULL;
        return NULL;
}

/** Recursively create items in sysinfo tree
 *
 * Should be called with sysinfo_lock held.
 *
 * @param name     Current sysinfo path suffix.
 * @param psubtree Pointer to an already existing (sub)tree root
 *                 item or where to store a new tree root item.
 *
 * @return Existing or newly allocated sysinfo item or NULL
 *         if the current tree configuration does not allow to
 *         create a new item.
 *
 */
static sysinfo_item_t *sysinfo_create_path(const char *name,
    sysinfo_item_t **psubtree)
{
        ASSERT(psubtree != NULL);
        
        if (*psubtree == NULL) {
                /* No parent */
                
                size_t i = 0;
                
                /* Find the first delimiter in name */
                while ((name[i] != 0) && (name[i] != '.'))
                        i++;
                
                *psubtree =
                    (sysinfo_item_t *) slab_alloc(sysinfo_item_slab, 0);
                ASSERT(*psubtree);
                
                /* Fill in item name up to the delimiter */
                (*psubtree)->name = str_ndup(name, i);
                ASSERT((*psubtree)->name);
                
                /* Create subtree items */
                if (name[i] == '.') {
                        (*psubtree)->subtree_type = SYSINFO_SUBTREE_TABLE;
                        return sysinfo_create_path(name + i + 1,
                            &((*psubtree)->subtree.table));
                }
                
                /* No subtree needs to be created */
                return *psubtree;
        }
        
        sysinfo_item_t *cur = *psubtree;
        
        /* Walk all siblings */
        while (cur != NULL) {
                size_t i = 0;
                
                /* Compare name with path */
                while ((cur->name[i] != 0) && (name[i] == cur->name[i]))
                        i++;
                
                /* Check for perfect name and path match
                 * -> item is already present.
                 */
                if ((name[i] == 0) && (cur->name[i] == 0))
                        return cur;
                
                /* Partial match up to the delimiter */
                if ((name[i] == '.') && (cur->name[i] == 0)) {
                        switch (cur->subtree_type) {
                        case SYSINFO_SUBTREE_NONE:
                                /* No subtree yet, create one */
                                cur->subtree_type = SYSINFO_SUBTREE_TABLE;
                                return sysinfo_create_path(name + i + 1,
                                    &(cur->subtree.table));
                        case SYSINFO_SUBTREE_TABLE:
                                /* Subtree already created, add new sibling */
                                return sysinfo_create_path(name + i + 1,
                                    &(cur->subtree.table));
                        default:
                                /* Subtree items handled by a function, this
                                 * cannot be overriden by a constant item.
                                 */
                                return NULL;
                        }
                }
                
                /* No match and no more siblings to check
                 * -> create a new sibling item.
                 */
                if (cur->next == NULL) {
                        /* Find the first delimiter in name */
                        i = 0;
                        while ((name[i] != 0) && (name[i] != '.'))
                                i++;
                        
                        sysinfo_item_t *item =
                            (sysinfo_item_t *) slab_alloc(sysinfo_item_slab, 0);
                        ASSERT(item);
                        
                        cur->next = item;
                        
                        /* Fill in item name up to the delimiter */
                        item->name = str_ndup(name, i);
                        ASSERT(item->name);
                        
                        /* Create subtree items */
                        if (name[i] == '.') {
                                item->subtree_type = SYSINFO_SUBTREE_TABLE;
                                return sysinfo_create_path(name + i + 1,
                                    &(item->subtree.table));
                        }
                        
                        /* No subtree needs to be created */
                        return item;
                }
                
                cur = cur->next;
        }
        
        /* Unreachable */
        ASSERT(false);
        return NULL;
}

/** Set sysinfo item with a constant numeric value
 *
 * @param name Sysinfo path.
 * @param root Pointer to the root item or where to store
 *             a new root item (NULL for global sysinfo root).
 * @param val  Value to store in the item.
 *
 */
void sysinfo_set_item_val(const char *name, sysinfo_item_t **root,
    unative_t val)
{
        /* Protect sysinfo tree consistency */
        mutex_lock(&sysinfo_lock);
        
        if (root == NULL)
                root = &global_root;
        
        sysinfo_item_t *item = sysinfo_create_path(name, root);
        if (item != NULL) {
                item->val_type = SYSINFO_VAL_VAL;
                item->val.val = val;
        }
        
        mutex_unlock(&sysinfo_lock);
}

/** Set sysinfo item with a constant binary data
 *
 * Note that sysinfo only stores the pointer to the
 * binary data and does not touch it in any way. The
 * data should be static and immortal.
 *
 * @param name Sysinfo path.
 * @param root Pointer to the root item or where to store
 *             a new root item (NULL for global sysinfo root).
 * @param data Binary data.
 * @param size Size of the binary data.
 *
 */
void sysinfo_set_item_data(const char *name, sysinfo_item_t **root,
    void *data, size_t size)
{
        /* Protect sysinfo tree consistency */
        mutex_lock(&sysinfo_lock);
        
        if (root == NULL)
                root = &global_root;
        
        sysinfo_item_t *item = sysinfo_create_path(name, root);
        if (item != NULL) {
                item->val_type = SYSINFO_VAL_DATA;
                item->val.data.data = data;
                item->val.data.size = size;
        }
        
        mutex_unlock(&sysinfo_lock);
}

/** Set sysinfo item with a generated numeric value
 *
 * @param name Sysinfo path.
 * @param root Pointer to the root item or where to store
 *             a new root item (NULL for global sysinfo root).
 * @param fn   Numeric value generator function.
 *
 */
void sysinfo_set_item_fn_val(const char *name, sysinfo_item_t **root,
    sysinfo_fn_val_t fn)
{
        /* Protect sysinfo tree consistency */
        mutex_lock(&sysinfo_lock);
        
        if (root == NULL)
                root = &global_root;
        
        sysinfo_item_t *item = sysinfo_create_path(name, root);
        if (item != NULL) {
                item->val_type = SYSINFO_VAL_FUNCTION_VAL;
                item->val.fn_val = fn;
        }
        
        mutex_unlock(&sysinfo_lock);
}

/** Set sysinfo item with a generated binary data
 *
 * Note that each time the generator function is called
 * it is supposed to return a new dynamically allocated
 * data. This data is then freed by sysinfo in the context
 * of the current sysinfo request.
 *
 * @param name Sysinfo path.
 * @param root Pointer to the root item or where to store
 *             a new root item (NULL for global sysinfo root).
 * @param fn   Binary data generator function.
 *
 */
void sysinfo_set_item_fn_data(const char *name, sysinfo_item_t **root,
    sysinfo_fn_data_t fn)
{
        /* Protect sysinfo tree consistency */
        mutex_lock(&sysinfo_lock);
        
        if (root == NULL)
                root = &global_root;
        
        sysinfo_item_t *item = sysinfo_create_path(name, root);
        if (item != NULL) {
                item->val_type = SYSINFO_VAL_FUNCTION_DATA;
                item->val.fn_data = fn;
        }
        
        mutex_unlock(&sysinfo_lock);
}

/** Set sysinfo item with an undefined value
 *
 * @param name Sysinfo path.
 * @param root Pointer to the root item or where to store
 *             a new root item (NULL for global sysinfo root).
 *
 */
void sysinfo_set_item_undefined(const char *name, sysinfo_item_t **root)
{
        /* Protect sysinfo tree consistency */
        mutex_lock(&sysinfo_lock);
        
        if (root == NULL)
                root = &global_root;
        
        sysinfo_item_t *item = sysinfo_create_path(name, root);
        if (item != NULL)
                item->val_type = SYSINFO_VAL_UNDEFINED;
        
        mutex_unlock(&sysinfo_lock);
}

/** Set sysinfo item with a generated subtree
 *
 * @param name Sysinfo path.
 * @param root Pointer to the root item or where to store
 *             a new root item (NULL for global sysinfo root).
 * @param fn   Subtree generator function.
 *
 */
void sysinfo_set_subtree_fn(const char *name, sysinfo_item_t **root,
    sysinfo_fn_subtree_t fn)
{
        /* Protect sysinfo tree consistency */
        mutex_lock(&sysinfo_lock);
        
        if (root == NULL)
                root = &global_root;
        
        sysinfo_item_t *item = sysinfo_create_path(name, root);
        
        /* Change the type of the subtree only if it is not already
           a fixed subtree */
        if ((item != NULL) && (item->subtree_type != SYSINFO_SUBTREE_TABLE)) {
                item->subtree_type = SYSINFO_SUBTREE_FUNCTION;
                item->subtree.get_data = fn;
        }
        
        mutex_unlock(&sysinfo_lock);
}

/** Sysinfo dump indentation helper routine
 *
 * @param depth Number of indentation characters to print.
 *
 */
static void sysinfo_indent(unsigned int depth)
{
        unsigned int i;
        for (i = 0; i < depth; i++)
                printf("  ");
}

/** Dump the structure of sysinfo tree
 *
 * Should be called with sysinfo_lock held.
 *
 * @param root  Root item of the current (sub)tree.
 * @param depth Current depth in the sysinfo tree.
 *
 */
static void sysinfo_dump_internal(sysinfo_item_t *root, unsigned int depth)
{
        sysinfo_item_t *cur = root;
        
        /* Walk all siblings */
        while (cur != NULL) {
                sysinfo_indent(depth);
                
                unative_t val;
                size_t size;
                
                /* Display node value and type */
                switch (cur->val_type) {
                case SYSINFO_VAL_UNDEFINED:
                        printf("+ %s\n", cur->name);
                        break;
                case SYSINFO_VAL_VAL:
                        printf("+ %s -> %" PRIun" (%#" PRIxn ")\n", cur->name,
                            cur->val.val, cur->val.val);
                        break;
                case SYSINFO_VAL_DATA:
                        printf("+ %s (%" PRIs" bytes)\n", cur->name,
                            cur->val.data.size);
                        break;
                case SYSINFO_VAL_FUNCTION_VAL:
                        val = cur->val.fn_val(cur);
                        printf("+ %s -> %" PRIun" (%#" PRIxn ") [generated]\n",
                            cur->name, val, val);
                        break;
                case SYSINFO_VAL_FUNCTION_DATA:
                        /* N.B.: No data was actually returned (only a dry run) */
                        (void) cur->val.fn_data(cur, &size, true);
                        printf("+ %s (%" PRIs" bytes) [generated]\n", cur->name,
                            size);
                        break;
                default:
                        printf("+ %s [unknown]\n", cur->name);
                }
                
                /* Recursivelly nest into the subtree */
                switch (cur->subtree_type) {
                case SYSINFO_SUBTREE_NONE:
                        break;
                case SYSINFO_SUBTREE_TABLE:
                        sysinfo_dump_internal(cur->subtree.table, depth + 1);
                        break;
                case SYSINFO_SUBTREE_FUNCTION:
                        sysinfo_indent(depth + 1);
                        printf("+ [generated subtree]\n");
                        break;
                default:
                        sysinfo_indent(depth + 1);
                        printf("+ [unknown subtree]\n");
                }
                
                cur = cur->next;
        }
}

/** Dump the structure of sysinfo tree
 *
 * @param root  Root item of the sysinfo (sub)tree.
 *              If it is NULL then consider the global
 *              sysinfo tree.
 *
 */
void sysinfo_dump(sysinfo_item_t *root)
{
        /* Avoid other functions to mess with sysinfo
           while we are dumping it */
        mutex_lock(&sysinfo_lock);
        
        if (root == NULL)
                sysinfo_dump_internal(global_root, 0);
        else
                sysinfo_dump_internal(root, 0);
        
        mutex_unlock(&sysinfo_lock);
}

/** Return sysinfo item value determined by name
 *
 * Should be called with sysinfo_lock held.
 *
 * @param name    Sysinfo path.
 * @param root    Root item of the sysinfo (sub)tree.
 *                If it is NULL then consider the global
 *                sysinfo tree.
 * @param dry_run Do not actually get any generated
 *                binary data, just calculate the size.
 *
 * @return Item value (constant or generated).
 *
 */
static sysinfo_return_t sysinfo_get_item(const char *name,
    sysinfo_item_t **root, bool dry_run)
{
        if (root == NULL)
                root = &global_root;
        
        /* Try to find the item or generate data */
        sysinfo_return_t ret;
        sysinfo_return_t *ret_ptr = &ret;
        sysinfo_item_t *item = sysinfo_find_item(name, *root, &ret_ptr,
            dry_run);
        
        if (item != NULL) {
                /* Item found in the fixed sysinfo tree */
                
                ret.tag = item->val_type;
                switch (item->val_type) {
                case SYSINFO_VAL_UNDEFINED:
                        break;
                case SYSINFO_VAL_VAL:
                        ret.val = item->val.val;
                        break;
                case SYSINFO_VAL_DATA:
                        ret.data = item->val.data;
                        break;
                case SYSINFO_VAL_FUNCTION_VAL:
                        ret.val = item->val.fn_val(item);
                        break;
                case SYSINFO_VAL_FUNCTION_DATA:
                        ret.data.data = item->val.fn_data(item, &ret.data.size,
                            dry_run);
                        break;
                }
        } else {
                /* No item in the fixed sysinfo tree */
                if (ret_ptr == NULL) {
                        /* Even no data was generated */
                        ret.tag = SYSINFO_VAL_UNDEFINED;
                }
        }
        
        return ret;
}

/** Return sysinfo item determined by name from user space
 *
 * The path string passed from the user space has to be properly null-terminated
 * (the last passed character must be null).
 *
 * @param ptr     Sysinfo path in the user address space.
 * @param size    Size of the path string.
 * @param dry_run Do not actually get any generated
 *                binary data, just calculate the size.
 *
 */
static sysinfo_return_t sysinfo_get_item_uspace(void *ptr, size_t size,
    bool dry_run)
{
        sysinfo_return_t ret;
        ret.tag = SYSINFO_VAL_UNDEFINED;
        
        if (size > SYSINFO_MAX_PATH)
                return ret;
        
        char *path = (char *) malloc(size + 1, 0);
        ASSERT(path);
        
        if ((copy_from_uspace(path, ptr, size + 1) == 0)
            && (path[size] == 0)) {
                /*
                 * Prevent other functions from messing with sysinfo while we
                 * are reading it.
                 */
                mutex_lock(&sysinfo_lock);
                ret = sysinfo_get_item(path, NULL, dry_run);
                mutex_unlock(&sysinfo_lock);
        }
        free(path);
        return ret;
}

/** Get the sysinfo value type (syscall)
 *
 * The path string passed from the user space has
 * to be properly null-terminated (the last passed
 * character must be null).
 *
 * @param path_ptr  Sysinfo path in the user address space.
 * @param path_size Size of the path string.
 *
 * @return Item value type.
 *
 */
unative_t sys_sysinfo_get_tag(void *path_ptr, size_t path_size)
{
        /*
         * Get the item.
         *
         * N.B.: There is no need to free any potential generated
         * binary data since we request a dry run.
         */
        sysinfo_return_t ret = sysinfo_get_item_uspace(path_ptr, path_size, true);
        
        /*
         * Map generated value types to constant types (user space does not care
         * whether the value is constant or generated).
         */
        if (ret.tag == SYSINFO_VAL_FUNCTION_VAL)
                ret.tag = SYSINFO_VAL_VAL;
        else if (ret.tag == SYSINFO_VAL_FUNCTION_DATA)
                ret.tag = SYSINFO_VAL_DATA;
        
        return (unative_t) ret.tag;
}

/** Get the sysinfo numerical value (syscall)
 *
 * The path string passed from the user space has
 * to be properly null-terminated (the last passed
 * character must be null).
 *
 * @param path_ptr  Sysinfo path in the user address space.
 * @param path_size Size of the path string.
 * @param value_ptr User space pointer where to store the
 *                  numberical value.
 *
 * @return Error code (EOK in case of no error).
 *
 */
unative_t sys_sysinfo_get_value(void *path_ptr, size_t path_size,
    void *value_ptr)
{
        int rc;

        /*
         * Get the item.
         *
         * N.B.: There is no need to free any potential generated binary data
         * since we request a dry run.
         */
        sysinfo_return_t ret = sysinfo_get_item_uspace(path_ptr, path_size, true);
        
        /* Only constant or generated numerical value is returned */
        if ((ret.tag == SYSINFO_VAL_VAL) || (ret.tag == SYSINFO_VAL_FUNCTION_VAL))
                rc = copy_to_uspace(value_ptr, &ret.val, sizeof(ret.val));
        else
                rc = EINVAL;
        
        return (unative_t) rc;
}

/** Get the sysinfo binary data size (syscall)
 *
 * The path string passed from the user space has
 * to be properly null-terminated (the last passed
 * character must be null).
 *
 * @param path_ptr  Sysinfo path in the user address space.
 * @param path_size Size of the path string.
 * @param size_ptr  User space pointer where to store the
 *                  binary data size.
 *
 * @return Error code (EOK in case of no error).
 *
 */
unative_t sys_sysinfo_get_data_size(void *path_ptr, size_t path_size,
    void *size_ptr)
{
        int rc;
        
        /*
         * Get the item.
         *
         * N.B.: There is no need to free any potential generated binary data
         * since we request a dry run.
         */
        sysinfo_return_t ret = sysinfo_get_item_uspace(path_ptr, path_size, true);
        
        /* Only the size of constant or generated binary data is considered */
        if ((ret.tag == SYSINFO_VAL_DATA) || (ret.tag == SYSINFO_VAL_FUNCTION_DATA))
                rc = copy_to_uspace(size_ptr, &ret.data.size,
                    sizeof(ret.data.size));
        else
                rc = EINVAL;
        
        return (unative_t) rc;
}

/** Get the sysinfo binary data (syscall)
 *
 * The path string passed from the user space has
 * to be properly null-terminated (the last passed
 * character must be null).
 *
 * The user space buffer must be sized exactly according
 * to the size of the binary data, otherwise the request
 * fails.
 *
 * @param path_ptr    Sysinfo path in the user address space.
 * @param path_size   Size of the path string.
 * @param buffer_ptr  User space pointer to the buffer where
 *                    to store the binary data.
 * @param buffer_size User space buffer size.
 *
 * @return Error code (EOK in case of no error).
 *
 */
unative_t sys_sysinfo_get_data(void *path_ptr, size_t path_size,
    void *buffer_ptr, size_t buffer_size)
{
        int rc;
        
        /* Get the item */
        sysinfo_return_t ret = sysinfo_get_item_uspace(path_ptr, path_size, false);

        /* Only constant or generated binary data is considered */
        if ((ret.tag == SYSINFO_VAL_DATA) || (ret.tag == SYSINFO_VAL_FUNCTION_DATA)) {
                /* Check destination buffer size */
                if (ret.data.size == buffer_size)
                        rc = copy_to_uspace(buffer_ptr, ret.data.data,
                            ret.data.size);
                else
                        rc = ENOMEM;
        } else
                rc = EINVAL;
        
        /* N.B.: The generated binary data should be freed */
        if ((ret.tag == SYSINFO_VAL_FUNCTION_DATA) && (ret.data.data != NULL))
                free(ret.data.data);
        
        return (unative_t) rc;
}

/** @}
 */