libisofs/src/tree.c

/*
 * Copyright (c) 2007 Vreixo Formoso
 * 
 * This file is part of the libisofs project; you can redistribute it and/or 
 * modify it under the terms of the GNU General Public License version 2 as 
 * published by the Free Software Foundation. See COPYING file for details.
 */

/*
 * Functions that act on the iso tree.
 */

#include "libisofs.h"
#include "node.h"
#include "error.h"

#include <stdlib.h>
#include <string.h>
#include <time.h>

/**
 * Add a new directory to the iso tree.
 * 
 * @param parent 
 *      the dir where the new directory will be created
 * @param name
 *      name for the new dir. If a node with same name already exists on
 *      parent, this functions fails with ISO_NODE_NAME_NOT_UNIQUE.
 * @param dir
 *      place where to store a pointer to the newly created dir. No extra
 *      ref is addded, so you will need to call iso_node_ref() if you really
 *      need it. You can pass NULL in this parameter if you don't need the
 *      pointer.
 * @return
 *     number of nodes in dir if succes, < 0 otherwise
 *     Possible errors:
 *         ISO_NULL_POINTER, if parent or name are NULL
 *         ISO_NODE_NAME_NOT_UNIQUE, a node with same name already exists
 */
int iso_tree_add_new_dir(IsoDir *parent, const char *name, IsoDir **dir)
{
    IsoDir *node;
    IsoNode **pos;
    time_t now;
    
    if (parent == NULL || name == NULL) {
        return ISO_NULL_POINTER;
    }
    if (dir) {
        *dir = NULL;
    }
    
    /* find place where to insert */
    pos = &(parent->children);
    while (*pos != NULL && strcmp((*pos)->name, name) < 0) {
        pos = &((*pos)->next);
    }
    if (*pos != NULL && !strcmp((*pos)->name, name)) {
        /* a node with same name already exists */
        return ISO_NODE_NAME_NOT_UNIQUE;
    }
    
    node = calloc(1, sizeof(IsoDir));
    if (node == NULL) {
        return ISO_MEM_ERROR;
    }
    
    node->node.refcount = 1;
    node->node.type = LIBISO_DIR;
    node->node.name = strdup(name);
    if (node->node.name == NULL) {
        free(node);
        return ISO_MEM_ERROR;
    }
    
    /* permissions from parent */
    node->node.mode = parent->node.mode;
    node->node.uid = parent->node.uid;
    node->node.gid = parent->node.gid;
    node->node.hidden = parent->node.hidden;
    
    /* current time */
    now = time(NULL);
    node->node.atime = now;
    node->node.ctime = now;
    node->node.mtime = now;
    
    /* add to dir */
    node->node.parent = parent;
    node->node.next = *pos;
    *pos = (IsoNode*)node;
    
    if (dir) {
        *dir = node;
    }
    return ++parent->nchildren;
}

/**
 * Add a new symlink to the directory tree. Permissions are set to 0777, 
 * owner and hidden atts are taken from parent. You can modify any of them 
 * later.
 *  
 * @param parent 
 *      the dir where the new symlink will be created
 * @param name
 *      name for the new dir. If a node with same name already exists on
 *      parent, this functions fails with ISO_NODE_NAME_NOT_UNIQUE.
 * @param dest
 *      destination of the link
 * @param link
 *      place where to store a pointer to the newly created link. No extra
 *      ref is addded, so you will need to call iso_node_ref() if you really
 *      need it. You can pass NULL in this parameter if you don't need the
 *      pointer
 * @return
 *     number of nodes in parent if success, < 0 otherwise
 *     Possible errors:
 *         ISO_NULL_POINTER, if parent, name or dest are NULL
 *         ISO_NODE_NAME_NOT_UNIQUE, a node with same name already exists
 *         ISO_MEM_ERROR
 */
int iso_tree_add_new_symlink(IsoDir *parent, const char *name, 
                             const char *dest, IsoSymlink **link)
{
    IsoSymlink *node;
    IsoNode **pos;
    time_t now;
    
    if (parent == NULL || name == NULL || dest == NULL) {
        return ISO_NULL_POINTER;
    }
    if (link) {
        *link = NULL;
    }
    
    /* find place where to insert */
    pos = &(parent->children);
    while (*pos != NULL && strcmp((*pos)->name, name) < 0) {
        pos = &((*pos)->next);
    }
    if (*pos != NULL && !strcmp((*pos)->name, name)) {
        /* a node with same name already exists */
        return ISO_NODE_NAME_NOT_UNIQUE;
    }
    
    node = calloc(1, sizeof(IsoSymlink));
    if (node == NULL) {
        return ISO_MEM_ERROR;
    }
    
    node->node.refcount = 1;
    node->node.type = LIBISO_SYMLINK;
    node->node.name = strdup(name);
    if (node->node.name == NULL) {
        free(node);
        return ISO_MEM_ERROR;
    }
    
    node->dest = strdup(dest);
    if (node->dest == NULL) {
        free(node->node.name);
        free(node);
        return ISO_MEM_ERROR;
    }
    
    /* permissions from parent */
    node->node.mode = S_IFLNK | 0777;
    node->node.uid = parent->node.uid;
    node->node.gid = parent->node.gid;
    node->node.hidden = parent->node.hidden;
    
    /* current time */
    now = time(NULL);
    node->node.atime = now;
    node->node.ctime = now;
    node->node.mtime = now;
    
    /* add to dir */
    node->node.parent = parent;
    node->node.next = *pos;
    *pos = (IsoNode*)node;
    
    if (link) {
        *link = node;
    }
    return ++parent->nchildren;
}

/**
 * Add a new special file to the directory tree. As far as libisofs concerns,
 * an special file is a block device, a character device, a FIFO (named pipe)
 * or a socket. You can choose the specific kind of file you want to add
 * by setting mode propertly (see man 2 stat).
 * 
 * Note that special files are only written to image when Rock Ridge 
 * extensions are enabled. Moreover, a special file is just a directory entry
 * in the image tree, no data is written beyond that.
 * 
 * Owner and hidden atts are taken from parent. You can modify any of them 
 * later.
 * 
 * @param parent
 *      the dir where the new special file will be created
 * @param name
 *      name for the new special file. If a node with same name already exists 
 *      on parent, this functions fails with ISO_NODE_NAME_NOT_UNIQUE.
 * @param mode
 *      file type and permissions for the new node. Note that you can't
 *      specify any kind of file here, only special types are allowed. i.e,
 *      S_IFSOCK, S_IFBLK, S_IFCHR and S_IFIFO are valid types; S_IFLNK, 
 *      S_IFREG and S_IFDIR aren't.
 * @param dev
 *      device ID, equivalent to the st_rdev field in man 2 stat.
 * @param special
 *      place where to store a pointer to the newly created special file. No 
 *      extra ref is addded, so you will need to call iso_node_ref() if you 
 *      really need it. You can pass NULL in this parameter if you don't need 
 *      the pointer.
 * @return
 *     number of nodes in parent if success, < 0 otherwise
 *     Possible errors:
 *         ISO_NULL_POINTER, if parent, name or dest are NULL
 *         ISO_NODE_NAME_NOT_UNIQUE, a node with same name already exists
 *         ISO_MEM_ERROR
 * 
 */
int iso_tree_add_new_special(IsoDir *parent, const char *name, mode_t mode, 
                             dev_t dev, IsoSpecial **special)
{
    IsoSpecial *node;
    IsoNode **pos;
    time_t now;
    
    if (parent == NULL || name == NULL) {
        return ISO_NULL_POINTER;
    }
    if (S_ISLNK(mode) || S_ISREG(mode) || S_ISDIR(mode)) {
        return ISO_WRONG_ARG_VALUE;
    }
    if (special) {
        *special = NULL;
    }
    
    /* find place where to insert */
    pos = &(parent->children);
    while (*pos != NULL && strcmp((*pos)->name, name) < 0) {
        pos = &((*pos)->next);
    }
    if (*pos != NULL && !strcmp((*pos)->name, name)) {
        /* a node with same name already exists */
        return ISO_NODE_NAME_NOT_UNIQUE;
    }
    
    node = calloc(1, sizeof(IsoSpecial));
    if (node == NULL) {
        return ISO_MEM_ERROR;
    }
    
    node->node.refcount = 1;
    node->node.type = LIBISO_SPECIAL;
    node->node.name = strdup(name);
    if (node->node.name == NULL) {
        free(node);
        return ISO_MEM_ERROR;
    }
    
    node->node.mode = mode;
    node->dev = dev;
    
    /* atts from parent */
    node->node.uid = parent->node.uid;
    node->node.gid = parent->node.gid;
    node->node.hidden = parent->node.hidden;
    
    /* current time */
    now = time(NULL);
    node->node.atime = now;
    node->node.ctime = now;
    node->node.mtime = now;
    
    /* add to dir */
    node->node.parent = parent;
    node->node.next = *pos;
    *pos = (IsoNode*)node;
    
    if (special) {
        *special = node;
    }
    return ++parent->nchildren;
}