C++ path_get函数代码示例

/*
 * Get the current working directory for the current process.
 * Returns the pointer to the string, which is NOT going to be at the beginning
 * of buf.
 * Buf must be at least 1 page in size.
 */
char *npm_getcwd(char *buf, unsigned long bufsize)
{
	struct path pwd;
	char *res;

	ASSERT(bufsize >= PAGE_SIZE - 1);

#if LINUX_VERSION_CODE >= KERNEL_VERSION(2, 6, 36) || defined CONFIG_VE
	get_fs_pwd(current->fs, &pwd);
#else
	read_lock(&current->fs->lock);
	pwd = current->fs->pwd;
	path_get(&pwd);
	read_unlock(&current->fs->lock);
#endif

	res = d_path(&pwd, buf, bufsize);

	if (IS_ERR(res))
		res = NULL;

	path_put(&pwd);

	return res;
}

/* Find the topmost mount satisfying test() */
static int find_autofs_mount(const char *pathname,
			     struct path *res,
			     int test(const struct path *path, void *data),
			     void *data)
{
	struct path path;
	int err;

	err = kern_path_mountpoint(AT_FDCWD, pathname, &path, 0);
	if (err)
		return err;
	err = -ENOENT;
	while (path.dentry == path.mnt->mnt_root) {
		if (path.dentry->d_sb->s_magic == AUTOFS_SUPER_MAGIC) {
			if (test(&path, data)) {
				path_get(&path);
				*res = path;
				err = 0;
				break;
			}
		}
		if (!follow_up(&path))
			break;
	}
	path_put(&path);
	return err;
}

static int find_autofs_mount(const char *pathname,
			     struct path *res,
			     int test(struct path *path, void *data),
			     void *data)
{
	struct path path;
	int err = kern_path(pathname, 0, &path);
	if (err)
		return err;
	err = -ENOENT;
	while (path.dentry == path.mnt->mnt_root) {
		if (path.mnt->mnt_sb->s_magic == AUTOFS_SUPER_MAGIC) {
			if (test(&path, data)) {
				path_get(&path);
				if (!err) /* already found some */
					path_put(res);
				*res = path;
				err = 0;
			}
		}
		if (!follow_up(&path))
			break;
	}
	path_put(&path);
	return err;
}

struct dentry *au_lkup_one(struct qstr *name, struct dentry *h_parent,
			   struct au_branch *br, struct nameidata *nd)
{
	struct dentry *h_dentry;
	int err;
	struct nameidata h_nd;

	if (au_test_fs_null_nd(h_parent->d_sb))
		return vfsub_lookup_one_len(name->name, h_parent, name->len);

	au_h_nd(&h_nd, nd);
	h_nd.path.dentry = h_parent;
	h_nd.path.mnt = br->br_mnt;

	err = __lookup_one_len(name->name, &h_nd.last, NULL, name->len);
	h_dentry = ERR_PTR(err);
	if (!err) {
		path_get(&h_nd.path);
		h_dentry = vfsub_lookup_hash(&h_nd);
		path_put(&h_nd.path);
	}

	AuTraceErrPtr(h_dentry);
	return h_dentry;
}

/*
 * Preparse a big key
 */
int big_key_preparse(struct key_preparsed_payload *prep)
{
	struct path *path = (struct path *)&prep->payload.data[big_key_path];
	struct file *file;
	ssize_t written;
	size_t datalen = prep->datalen;
	int ret;

	ret = -EINVAL;
	if (datalen <= 0 || datalen > 1024 * 1024 || !prep->data)
		goto error;

	/* Set an arbitrary quota */
	prep->quotalen = 16;

	prep->payload.data[big_key_len] = (void *)(unsigned long)datalen;

	if (datalen > BIG_KEY_FILE_THRESHOLD) {
		/* Create a shmem file to store the data in.  This will permit the data
		 * to be swapped out if needed.
		 *
		 * TODO: Encrypt the stored data with a temporary key.
		 */
		file = shmem_kernel_file_setup("", datalen, 0);
		if (IS_ERR(file)) {
			ret = PTR_ERR(file);
			goto error;
		}

		written = kernel_write(file, prep->data, prep->datalen, 0);
		if (written != datalen) {
			ret = written;
			if (written >= 0)
				ret = -ENOMEM;
			goto err_fput;
		}

		/* Pin the mount and dentry to the key so that we can open it again
		 * later
		 */
		*path = file->f_path;
		path_get(path);
		fput(file);
	} else {
		/* Just store the data in a buffer */
		void *data = kmalloc(datalen, GFP_KERNEL);
		if (!data)
			return -ENOMEM;

		prep->payload.data[big_key_data] = data;
		memcpy(data, prep->data, prep->datalen);
	}
	return 0;

err_fput:
	fput(file);
error:
	return ret;
}

bool HashSet::store( ) const
{
   OutputFile out;

   for ( const auto &id : _set )
      id.store( out );

   return out.rename( path_get( PathType::OBJ, "index" ).string( ) );
}

/*
 * Here the caller only guarantees locking for struct file and struct inode.
 * Locking must therefore be done in the probe to use the dentry.
 */
static void probe_subsys_event(struct inode *inode, struct file *file)
{
	path_get(&file->f_path);
	dget(file->f_path.dentry);
	printk(KERN_INFO "Event is encountered with filename %s\n",
		file->f_path.dentry->d_name.name);
	dput(file->f_path.dentry);
	path_put(&file->f_path);
}

static void menu_action_setting_disp_set_label_core_option_create(
      file_list_t* list,
      unsigned *w, unsigned type, unsigned i,
      const char *label,
      char *s, size_t len,
      const char *entry_label,
      const char *path,
      char *s2, size_t len2)
{
   *s = '\0';
   *w = 19;

   strlcpy(s, "", len);

   if (!string_is_empty(path_get(RARCH_PATH_BASENAME)))
      strlcpy(s,  path_basename(path_get(RARCH_PATH_BASENAME)), len);

   strlcpy(s2, path, len2);
}

static void frontend_xdk_exec(const char *path, bool should_load_game)
{
#ifndef IS_SALAMANDER
   bool original_verbose       = verbosity_is_enabled();
#endif
#if defined(_XBOX1)
   LAUNCH_DATA ptr;
#elif defined(_XBOX360)
   char game_path[1024] = {0};
#endif
   (void)should_load_game;

#ifdef IS_SALAMANDER
   if (!string_is_empty(path))
      XLaunchNewImage(path, NULL);
#else
#if defined(_XBOX1)
   memset(&ptr, 0, sizeof(ptr));

   if (should_load_game && !path_is_empty(RARCH_PATH_CONTENT))
      snprintf((char*)ptr.Data, sizeof(ptr.Data), "%s", path_get(RARCH_PATH_CONTENT));

   if (!string_is_empty(path))
      XLaunchNewImage(path, !string_is_empty((const char*)ptr.Data) ? &ptr : NULL);
#elif defined(_XBOX360)
   if (should_load_game && !path_is_empty(RARCH_PATH_CONTENT))
   {
      strlcpy(game_path, path_get(RARCH_PATH_CONTENT), sizeof(game_path));
      XSetLaunchData(game_path, MAX_LAUNCH_DATA_SIZE);
   }

   if (!string_is_empty(path))
      XLaunchNewImage(path, 0);
#endif
#endif
#ifndef IS_SALAMANDER
   if (original_verbose)
      verbosity_enable();
   else
      verbosity_disable();
#endif
}

static void load_dynamic_core(void)
{
   function_t sym       = dylib_proc(NULL, "retro_init");

   if (sym)
   {
      /* Try to verify that -lretro was not linked in from other modules
       * since loading it dynamically and with -l will fail hard. */
      RARCH_ERR("Serious problem. RetroArch wants to load libretro cores"
            "dyamically, but it is already linked.\n");
      RARCH_ERR("This could happen if other modules RetroArch depends on "
            "link against libretro directly.\n");
      RARCH_ERR("Proceeding could cause a crash. Aborting ...\n");
      retroarch_fail(1, "init_libretro_sym()");
   }

   if (string_is_empty(path_get(RARCH_PATH_CORE)))
   {
      RARCH_ERR("RetroArch is built for dynamic libretro cores, but "
            "libretro_path is not set. Cannot continue.\n");
      retroarch_fail(1, "init_libretro_sym()");
   }

   /* Need to use absolute path for this setting. It can be
    * saved to content history, and a relative path would
    * break in that scenario. */
   path_resolve_realpath(
         path_get_ptr(RARCH_PATH_CORE),
         path_get_realsize(RARCH_PATH_CORE));

   RARCH_LOG("Loading dynamic libretro core from: \"%s\"\n",
         path_get(RARCH_PATH_CORE));
   lib_handle = dylib_load(path_get(RARCH_PATH_CORE));
   if (!lib_handle)
   {
      RARCH_ERR("Failed to open libretro core: \"%s\"\n",
            path_get(RARCH_PATH_CORE));
      RARCH_ERR("Error(s): %s\n", dylib_error());
      retroarch_fail(1, "load_dynamic()");
   }
}

bool HashSet::load( )
{
   InputFile   in( path_get( PathType::OBJ, "index" ).string( ) );
   HashId      id;

   while ( id.load( in ) )
      _set.insert( id );

   _old_size = _set.size( );

   return true;
}

// ARM10C 20160521
// current->fs: (&init_task)->fs, &root
void set_fs_pwd(struct fs_struct *fs, const struct path *path)
{
	struct path old_pwd;

	// path: &root
	path_get(path);

	// path_get에서 한일:
	// [pcp0] (kmem_cache#2-oX (struct mount))->mnt_pcp->mnt_count 을 1만큼 증가 시킴
	// (&(kmem_cache#5-oX (struct dentry))->d_lockref)->count: 1 만큼 증가 시킴

	// &fs->lock: &((&init_task)->fs)->lock
	spin_lock(&fs->lock);

	// spin_lock 에서 한일:
	// &((&init_task)->fs)->lock 을 사용하여 spin lock 을 수행

	// &fs->seq: &((&init_task)->fs)->seq
	write_seqcount_begin(&fs->seq);

	// write_seqcount_begin에서 한일:
	// (&((&init_task)->fs)->seq)->sequence: 1
	// 공유자원을 다른 cpu core가 사용할수 있게 메모리 적용

	// fs->pwd: ((&init_task)->fs)->pwd: (&init_fs)->pwd: 맴버가 0 으로 초기화된 값
	old_pwd = fs->pwd;
	// old_pwd: 맴버가 0 으로 초기화된 값

	// root.mnt: &(kmem_cache#2-oX (struct mount))->mnt
	// root.dentry: kmem_cache#5-oX (struct dentry)

	// fs->pwd: ((&init_task)->fs)->pwd: (&init_fs)->pwd: 맴버가 0 으로 초기화된 값, *path: root
	fs->pwd = *path;
	// fs->pwd: ((&init_task)->fs)->pwd.mnt: &(kmem_cache#2-oX (struct mount))->mnt
	// fs->pwd: ((&init_task)->fs)->pwd.dentry: kmem_cache#5-oX (struct dentry)

	// &fs->seq: &((&init_task)->fs)->seq
	write_seqcount_end(&fs->seq);

	// write_seqcount_end에서 한일:
	// 공유자원을 다른 cpu core가 사용할수 있게 메모리 적용
	// (&((&init_task)->fs)->seq)->sequence: 2

	// &fs->lock: &((&init_task)->fs)->lock
	spin_unlock(&fs->lock);

	// spin_unlock 에서 한일:
	// &((&init_task)->fs)->lock 을 사용하여 spin unlock 을 수행

	// old_pwd.dentry: NULL
	if (old_pwd.dentry)
		path_put(&old_pwd);
}

static_fn char *nextdir(glob_t *gp, char *dir) {
    Shell_t *shp = sh_getinterp();
    Pathcomp_t *pp = gp->gl_handle;
    if (!dir) {
        pp = path_get(shp, "");
    } else {
        pp = pp->next;
    }
    gp->gl_handle = pp;
    if (pp) return pp->name;
    return NULL;
}

char *getfullPath(const char *pathname, char *fullpath) {
    //char *fullpath = NULL;
    char *path = NULL;
    char *start = NULL;
    //struct dentry *pwd;
    //struct vfsmount *vfsmount;
    
    struct fs_struct *fs = current->fs;
    
    struct path pwd;
    /*fullpath = kmalloc(PATH_MAX, GFP_KERNEL);
     if (!fullpath) {
     // kmalloc error
     return fullpath;
     }
     memset(fullpath, 0, PATH_MAX);*/
    
    path = kmalloc(PATH_MAX, GFP_KERNEL);
    if (!path) {
        return NULL;
    }
    // 2.4
    // get dentry and vfsmnt
    //read_lock(&(fs->lock));
    //pwd = dget(fs->pwd);
    //vfsmount = mntget(fs->pwdmnt);
    //read_unlock(&(fs->lock));
    
    // get path
    //start = d_path(pwd, vfsmount, path, PATH_MAX);
    //strcat(fullpath, start);
    
    // 2.6.32
    read_lock(&fs->lock);
    pwd = fs->pwd;
    path_get(&pwd);
    read_unlock(&fs->lock);
    //set_fs_pwd(fs, &pwd);
    start = d_path(&pwd, path, PATH_MAX);

    strcat(fullpath, start);
    strcat(fullpath, "/");
    strcat(fullpath, pathname);
    
    // 2.6.35
    // use spinlock
    
    kfree(path);
    return fullpath;
}

struct file *vfsub_dentry_open(struct path *path, int flags)
{
	struct file *file;

	path_get(path);
	file = dentry_open(path->dentry, path->mnt,
			   flags /* | __FMODE_NONOTIFY */,
			   current_cred());
	if (!IS_ERR_OR_NULL(file)
	    && (file->f_mode & (FMODE_READ | FMODE_WRITE)) == FMODE_READ)
		i_readcount_inc(path->dentry->d_inode);

	return file;
}