1 files changed, 295 insertions, 0 deletions
diff --git a/lib/util/sys_rw.c b/lib/util/sys_rw.c
new file mode 100644
index 0000000..d25a42b
--- /dev/null
+++ b/lib/util/sys_rw.c
@@ -0,0 +1,295 @@
+/*
+ * Unix SMB/CIFS implementation.
+ * Samba system utilities
+ * Copyright (C) Andrew Tridgell 1992-1998
+ * Copyright (C) Jeremy Allison  1998-2005
+ * Copyright (C) Timur Bakeyev        2005
+ * Copyright (C) Bjoern Jacke    2006-2007
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "replace.h"
+#include "system/filesys.h"
+#include "lib/util/sys_rw.h"
+#include <assert.h>
+
+bool sys_valid_io_range(off_t offset, size_t length)
+{
+	uint64_t last_byte_ofs;
+
+	if (offset < 0) {
+		return false;
+	}
+
+	if (offset > INT64_MAX) {
+		return false;
+	}
+
+	if (length > UINT32_MAX) {
+		return false;
+	}
+
+	last_byte_ofs = (uint64_t)offset + (uint64_t)length;
+	if (last_byte_ofs > INT64_MAX) {
+		return false;
+	}
+
+	return true;
+}
+
+bool sys_io_ranges_overlap(size_t c1, off_t o1,
+			   size_t c2, off_t o2)
+{
+	if (c1 == 0 || c2 == 0) {
+		return false;
+	}
+	if (o2 < o1) {
+		/*
+		 *          o1
+		 *          |····c1····|
+		 *  o2
+		 *  |····c2···| ?
+		 */
+		return (o2 + c2 > o1);
+	} else {
+		/*
+		 *  o1
+		 *  |····c1···|
+		 *          o2
+		 *          |····c2····| ?
+		 */
+		return (o1 + c1 > o2);
+	}
+}
+
+off_t sys_block_align_truncate(off_t len, off_t align)
+{
+	assert(align > 1);
+	assert(((align - 1) & align) == 0);
+	return len & (~align + 1);
+}
+
+off_t sys_block_align(off_t len, off_t align)
+{
+	assert(align > 1);
+	assert(((align - 1) & align) == 0);
+	return (len + (align - 1)) & ~(align - 1);
+}
+
+/*******************************************************************
+A read wrapper that will deal with EINTR/EWOULDBLOCK
+********************************************************************/
+
+ssize_t sys_read(int fd, void *buf, size_t count)
+{
+	ssize_t ret;
+
+	do {
+		ret = read(fd, buf, count);
+	} while (ret == -1 && (errno == EINTR || errno == EAGAIN ||
+			       errno == EWOULDBLOCK));
+
+	return ret;
+}
+
+/**
+ * read wrapper, void variant:
+ * This is intended to be used as a void variant of
+ * read in situations where the caller wants to ignore
+ * the result. Hence not checking for EAGAIN|EWOULDBLOCK.
+ */
+void sys_read_v(int fd, void *buf, size_t count)
+{
+	ssize_t ret;
+
+	do {
+		ret = read(fd, buf, count);
+	} while (ret == -1 && errno == EINTR);
+}
+
+
+/*******************************************************************
+A write wrapper that will deal with EINTR/EWOULDBLOCK.
+********************************************************************/
+
+ssize_t sys_write(int fd, const void *buf, size_t count)
+{
+	ssize_t ret;
+
+	do {
+		ret = write(fd, buf, count);
+	} while (ret == -1 && (errno == EINTR || errno == EAGAIN ||
+			       errno == EWOULDBLOCK));
+
+	return ret;
+}
+
+/**
+ * write wrapper to deal with EINTR and friends.
+ * void-variant that ignores the number of bytes written.
+ * This is intended to be used as a void variant of
+ * write in situations where the caller wants to ignore
+ * the result. Hence not checking for EAGAIN|EWOULDBLOCK.
+ */
+void sys_write_v(int fd, const void *buf, size_t count)
+{
+	ssize_t ret;
+
+	do {
+		ret = write(fd, buf, count);
+	} while (ret == -1 && errno == EINTR);
+}
+
+
+/*******************************************************************
+A writev wrapper that will deal with EINTR.
+********************************************************************/
+
+ssize_t sys_writev(int fd, const struct iovec *iov, int iovcnt)
+{
+	ssize_t ret;
+
+	do {
+		ret = writev(fd, iov, iovcnt);
+	} while (ret == -1 && (errno == EINTR || errno == EAGAIN ||
+			       errno == EWOULDBLOCK));
+
+	return ret;
+}
+
+/*******************************************************************
+A pread wrapper that will deal with EINTR
+********************************************************************/
+
+ssize_t sys_pread(int fd, void *buf, size_t count, off_t off)
+{
+	ssize_t ret;
+
+	do {
+		ret = pread(fd, buf, count, off);
+	} while (ret == -1 && errno == EINTR);
+	return ret;
+}
+
+/*******************************************************************
+ A pread wrapper that will deal with EINTR and never return a short
+ read unless pread returns zero meaning EOF.
+********************************************************************/
+
+ssize_t sys_pread_full(int fd, void *buf, size_t count, off_t off)
+{
+	ssize_t total_read = 0;
+	uint8_t *curr_buf = (uint8_t *)buf;
+	size_t curr_count = count;
+	off_t curr_off = off;
+	bool ok;
+
+	ok = sys_valid_io_range(off, count);
+	if (!ok) {
+		errno = EINVAL;
+		return -1;
+	}
+
+	while (curr_count != 0) {
+		ssize_t ret = sys_pread(fd,
+					curr_buf,
+					curr_count,
+					curr_off);
+
+		if (ret == -1) {
+			return -1;
+		}
+		if (ret == 0) {
+			/* EOF */
+			break;
+		}
+
+		if (ret > curr_count) {
+			errno = EIO;
+			return -1;
+		}
+
+		curr_buf += ret;
+		curr_count -= ret;
+		curr_off += ret;
+
+		total_read += ret;
+	}
+
+	return total_read;
+}
+
+/*******************************************************************
+A write wrapper that will deal with EINTR
+********************************************************************/
+
+ssize_t sys_pwrite(int fd, const void *buf, size_t count, off_t off)
+{
+	ssize_t ret;
+
+	do {
+		ret = pwrite(fd, buf, count, off);
+	} while (ret == -1 && errno == EINTR);
+	return ret;
+}
+
+/*******************************************************************
+ A pwrite wrapper that will deal with EINTR and never allow a short
+ write unless the file system returns an error.
+********************************************************************/
+
+ssize_t sys_pwrite_full(int fd, const void *buf, size_t count, off_t off)
+{
+	ssize_t total_written = 0;
+	const uint8_t *curr_buf = (const uint8_t *)buf;
+	size_t curr_count = count;
+	off_t curr_off = off;
+	bool ok;
+
+	ok = sys_valid_io_range(off, count);
+	if (!ok) {
+		errno = EINVAL;
+		return -1;
+	}
+
+	while (curr_count != 0) {
+		ssize_t ret = sys_pwrite(fd,
+					 curr_buf,
+					 curr_count,
+					 curr_off);
+
+		if (ret == -1) {
+			return -1;
+		}
+		if (ret == 0) {
+			/* Ensure we can never spin. */
+			errno = ENOSPC;
+			return -1;
+		}
+
+		if (ret > curr_count) {
+			errno = EIO;
+			return -1;
+		}
+
+		curr_buf += ret;
+		curr_count -= ret;
+		curr_off += ret;
+
+		total_written += ret;
+	}
+
+	return total_written;
+}