radare2/libr/io/p/io_default.c

/* radare - LGPL - Copyright 2008-2019 - pancake */

#include <r_userconf.h>
#include <r_io.h>
#include <r_lib.h>
#include <stdio.h>

typedef struct r_io_mmo_t {
	char * filename;
	int mode;
	int perm;
	int fd;
	int opened;
	bool nocache;
	ut8 modified;
	RBuffer *buf;
	RIO * io_backref;
	int rawio;
} RIOMMapFileObj;

static int __io_posix_open(const char *file, int perm, int mode) {
	int fd;
	if (r_str_startswith (file, "file://")) {
		file += strlen ("file://");
	}
	if (r_file_is_directory (file)) {
		return -1;
	}
#if __WINDOWS__
	// probably unnecessary to have this ifdef nowadays windows is posix enough
	if (perm & R_PERM_W) {
		fd = r_sandbox_open (file, O_RDWR, 0);
		if (fd == -1 && (perm & R_PERM_CREAT)) {
			r_sandbox_creat (file, 0644);
			fd = r_sandbox_open (file, O_RDWR | O_CREAT, 0);
		}
	} else {
		fd = r_sandbox_open (file, O_RDONLY | O_BINARY, 0);
	}
#else
	const int posixFlags = (perm & R_PERM_W) ? (perm & R_PERM_CREAT)
			? (O_RDWR | O_CREAT) : O_RDWR : O_RDONLY;
	fd = r_sandbox_open (file, posixFlags, mode);
#endif
	return fd;
}

static ut64 r_io_def_mmap_seek(RIO *io, RIOMMapFileObj *mmo, ut64 offset, int whence) {
	if (!mmo) {
		return UT64_MAX;
	}
	if (mmo->rawio) {
		io->off = lseek (mmo->fd, offset, whence);
		return io->off;
	}
	if (!mmo->buf) {
		return UT64_MAX;
	}
	io->off = r_buf_seek (mmo->buf, offset, whence);
	return io->off;
}

static int r_io_def_mmap_refresh_def_mmap_buf(RIOMMapFileObj *mmo) {
	RIO* io = mmo->io_backref;
	ut64 cur;
	if (mmo->buf) {
		cur = r_buf_tell (mmo->buf);
		r_buf_free (mmo->buf);
		mmo->buf = NULL;
	} else {
		cur = 0;
	}
	st64 sz = r_file_size (mmo->filename);
	if (sz > ST32_MAX) {
		// Do not use mmap if the file is huge
		mmo->rawio = 1;
	}
	if (mmo->rawio) {
		mmo->fd = __io_posix_open (mmo->filename, mmo->perm, mmo->mode);
		if (mmo->nocache) {
#ifdef F_NOCACHE
			fcntl (mmo->fd, F_NOCACHE, 1);
#endif
		}
		return (mmo->fd != -1);
	}
	mmo->buf = r_buf_new_mmap (mmo->filename, mmo->perm);
	if (mmo->buf) {
		r_io_def_mmap_seek (io, mmo, cur, SEEK_SET);
		return true;
	} else {
		mmo->rawio = 1;
		mmo->fd = __io_posix_open (mmo->filename, mmo->perm, mmo->mode);
		if (mmo->nocache) {
#ifdef F_NOCACHE
			fcntl (mmo->fd, F_NOCACHE, 1);
#endif
		}
		return (mmo->fd != -1);
	}
	return false;
}

static void r_io_def_mmap_free (RIOMMapFileObj *mmo) {
	if (mmo) {
		free (mmo->filename);
		r_buf_free (mmo->buf);
		close (mmo->fd);
		free (mmo);
	}
}

RIOMMapFileObj *r_io_def_mmap_create_new_file(RIO  *io, const char *filename, int perm, int mode) {
	r_return_val_if_fail (io && filename, NULL);
	RIOMMapFileObj *mmo = R_NEW0 (RIOMMapFileObj);
	if (!mmo) {
		return NULL;
	}
	if (r_str_startswith (filename, "file://")) {
		filename += strlen ("file://");
	}
	mmo->nocache = r_str_startswith (filename, "nocache://");
	if (mmo->nocache) {
		filename += strlen ("nocache://");;
	}
	mmo->filename = strdup (filename);
	mmo->perm = perm;
	mmo->mode = mode;
	mmo->io_backref = io;
	const int posixFlags = (perm & R_PERM_W)
			?(
				(perm & R_PERM_CREAT)
					? (O_RDWR | O_CREAT)
					: O_RDWR
			): O_RDONLY;
	mmo->fd = r_sandbox_open (filename, posixFlags, mode);
	if (mmo->fd == -1) {
		free (mmo->filename);
		free (mmo);
		return NULL;
	}
	if (!r_io_def_mmap_refresh_def_mmap_buf (mmo)) {
		mmo->rawio = 1;
		if (!r_io_def_mmap_refresh_def_mmap_buf (mmo)) {
			r_io_def_mmap_free (mmo);
			mmo = NULL;
		}
	}
	return mmo;
}

static int r_io_def_mmap_close(RIODesc *fd) {
	r_return_val_if_fail (fd && fd->data, -1);
	r_io_def_mmap_free ((RIOMMapFileObj *) fd->data);
	fd->data = NULL;
	return 0;
}

static bool r_io_def_mmap_check_default (const char *filename) {
	r_return_val_if_fail (filename && *filename, false);
	if (r_str_startswith (filename, "file://")) {
		filename += strlen ("file://");
	}
	const char * peekaboo = (!strncmp (filename, "nocache://", 10))
		? NULL : strstr (filename, "://");
	return (!peekaboo || (peekaboo - filename) > 10);
}

static int r_io_def_mmap_read(RIO *io, RIODesc *fd, ut8 *buf, int count) {
	r_return_val_if_fail (fd && fd->data && buf, -1);
	if (io->off == UT64_MAX) {
		memset (buf, 0xff, count);
		return count;
	}
	// TODO : unbox magic
	RIOMMapFileObj *mmo = fd->data;
	if (!mmo) {
		return -1;
	}
	if (mmo->rawio) {
		if (fd->obsz) {
			// only do aligned reads in aligned offsets
			const int aligned = fd->obsz;
			ut64 a_off = io->off - (io->off % aligned);
			int a_delta = io->off - a_off;
			if (a_delta < 0) {
				memset (buf, 0xff, count);
				return -1;
			}
			int a_count = count + (aligned - (count % aligned));

			char *a_buf = malloc (a_count + aligned);
			if (a_buf) {
				int i;
				memset (a_buf, 0xff, a_count + aligned);
				if (lseek (mmo->fd, a_off, SEEK_SET) < 0) {
					free (a_buf);
					return -1;
				}
				for (i = 0; i < a_count ; i += aligned) {
					(void)read (mmo->fd, a_buf+i, aligned);
				}
				memcpy (buf, a_buf+a_delta, count);
			} else {
				memset (buf, 0xff, count);
			}
			free (a_buf);
			return count;
		}
		if (lseek (mmo->fd, io->off, SEEK_SET) < 0) {
			return -1;
		}
		return read (mmo->fd, buf, count);
	}
	if (r_buf_size (mmo->buf) < io->off) {
		io->off = r_buf_size (mmo->buf);
	}
	int r = r_buf_read_at (mmo->buf, io->off, buf, count);
	if (r < 0) {
		return r;
	}
	r_buf_seek (mmo->buf, r, R_BUF_CUR);
	io->off += r;
	return r;
}

static int r_io_def_mmap_write(RIO *io, RIODesc *fd, const ut8 *buf, int count) {
	r_return_val_if_fail (io && fd && fd->data && buf, -1);

	int len = -1;
	ut64 addr = io->off;
	RIOMMapFileObj *mmo = fd->data;
	if (mmo->rawio) {
		if (fd->obsz) {
			char *a_buf;
			int a_count;
			// only do aligned reads in aligned offsets
			const int aligned = fd->obsz; //512; // XXX obey fd->obsz? or it may be too slow? 128K..
			//ut64 a_off = (io->off >> 9 ) << 9; //- (io->off & aligned);
			ut64 a_off = io->off - (io->off % aligned); //(io->off >> 9 ) << 9; //- (io->off & aligned);
			int a_delta = io->off - a_off;
			if (a_delta < 0) {
				return -1;
			}
			a_count = count + (aligned - (count % aligned));
			a_buf = malloc (a_count + aligned);
			if (a_buf) {
				int i;
				memset (a_buf, 0xff, a_count+aligned);
				for (i = 0; i < a_count; i += aligned) {
					(void)lseek (mmo->fd, a_off + i, SEEK_SET);
					(void)read (mmo->fd, a_buf + i, aligned);
				}
				memcpy (a_buf+a_delta, buf, count);
				for (i = 0; i < a_count; i += aligned) {
					(void)lseek (mmo->fd, a_off + i, SEEK_SET);
					len = write (mmo->fd, a_buf + i, aligned);
					if (len != aligned) {
						free (a_buf);
						return len;
					}
				}
			}
			free (a_buf);
			return count;
		}
		if (lseek (mmo->fd, addr, 0) < 0) {
			return -1;
		}
		len = write (mmo->fd, buf, count);
		return len;
	}

	if (mmo && mmo->buf) {
		if (!(mmo->perm & R_PERM_W)) {
			return -1;
		}
		if ( (count + addr > r_buf_size (mmo->buf)) || r_buf_size (mmo->buf) == 0) {
			ut64 sz = count + addr;
			r_file_truncate (mmo->filename, sz);
		}
	}

	len = r_file_mmap_write (mmo->filename, io->off, buf, count);
	if (len != count) {
		// aim to hack some corner cases?
		if (lseek (fd->fd, addr, 0) < 0) {
			return -1;
		}
		len = write (fd->fd, buf, count);
	}
	if (!r_io_def_mmap_refresh_def_mmap_buf (mmo) ) {
		eprintf ("io_def_mmap: failed to refresh the def_mmap backed buffer.\n");
		// XXX - not sure what needs to be done here (error handling).
	}
	return len;
}

static RIODesc *r_io_def_mmap_open(RIO *io, const char *file, int perm, int mode) {
	r_return_val_if_fail (io && file, NULL);
	RIOMMapFileObj *mmo = r_io_def_mmap_create_new_file (io, file, perm, mode);
	if (!mmo) {
		return NULL;
	}
	RIODesc *d = r_io_desc_new (io, &r_io_plugin_default, mmo->filename, perm, mode, mmo);
	if (!d->name) {
		d->name = strdup (file);
	}
	if (r_str_startswith (d->name, "file://")) {
		char *oldname = d->name;
		d->name = strdup (oldname + strlen ("file://"));
		free (oldname);
	}
	return d;
}

static ut64 r_io_def_mmap_lseek(RIO *io, RIODesc *fd, ut64 offset, int whence) {
	r_return_val_if_fail (fd && fd->data, UT64_MAX);
	return r_io_def_mmap_seek (io, (RIOMMapFileObj *)fd->data, offset, whence);
}

static int r_io_def_mmap_truncate(RIOMMapFileObj *mmo, ut64 size) {
	bool res = r_file_truncate (mmo->filename, size);
	if (res && !r_io_def_mmap_refresh_def_mmap_buf (mmo) ) {
		eprintf ("r_io_def_mmap_truncate: Error trying to refresh the def_mmap'ed file.");
		res = false;
	} else if (!res) {
		eprintf ("r_io_def_mmap_truncate: Error trying to resize the file.");
	}
	return res;
}

static bool __plugin_open_default(RIO *io, const char *file, bool many) {
	return r_io_def_mmap_check_default (file);
}

// default open should permit opening
static RIODesc *__open_default(RIO *io, const char *file, int perm, int mode) {
	if (r_io_def_mmap_check_default (file)) {
		return r_io_def_mmap_open (io, file, perm, mode);
	}
	return NULL;
}

static int __read(RIO *io, RIODesc *fd, ut8 *buf, int len) {
	return r_io_def_mmap_read (io, fd, buf, len);
}

static int __write(RIO *io, RIODesc *fd, const ut8 *buf, int len) {
	return r_io_def_mmap_write(io, fd, buf, len);
}

static ut64 __lseek(RIO *io, RIODesc *fd, ut64 offset, int whence) {
	return r_io_def_mmap_lseek (io, fd, offset, whence);
}

static int __close(RIODesc *fd) {
	return r_io_def_mmap_close (fd);
}

static bool __resize(RIO *io, RIODesc *fd, ut64 size) {
	r_return_val_if_fail (io && fd && fd->data, false);
	RIOMMapFileObj *mmo = fd->data;
	if (!(mmo->perm & R_PERM_W)) {
		return false;
	}
	return r_io_def_mmap_truncate (mmo, size);
}

#if __UNIX__
static bool __is_blockdevice (RIODesc *desc) {
	r_return_val_if_fail (desc && desc->data, false);
	RIOMMapFileObj *mmo = desc->data;
	struct stat buf;
	if (fstat (mmo->fd, &buf) == -1) {
		return false;
	}
	return ((buf.st_mode & S_IFBLK) == S_IFBLK);
}
#endif

RIOPlugin r_io_plugin_default = {
	.name = "default",
	.desc = "Open local files",
	.license = "LGPL3",
	.uris = "file://,nocache://",
	.open = __open_default,
	.close = __close,
	.read = __read,
	.check = __plugin_open_default,
	.lseek = __lseek,
	.write = __write,
	.resize = __resize,
#if __UNIX__
	.is_blockdevice = __is_blockdevice,
#endif
};

#ifndef R2_PLUGIN_INCORE
R_API RLibStruct radare_plugin = {
	.type = R_LIB_TYPE_IO,
	.data = &r_io_plugin_default,
	.version = R2_VERSION
};
#endif