From: Ralph Boehme <slow@samba.org>
Date: Sun, 24 Nov 2024 07:08:26 +0000 (+0100)
Subject: lib: add sys_write_full()
X-Git-Tag: tdb-1.4.13~221
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=127429a38ed4edb238e7d2a38dbae426e22751fe;p=thirdparty%2Fsamba.git

lib: add sys_write_full()

Basically a copy of sys_pwrite_full(), calling write() instead of pwrite().

Signed-off-by: Ralph Boehme <slow@samba.org>
Reviewed-by: Jeremy Allison <jra@samba.org>
---

diff --git a/lib/util/sys_rw.c b/lib/util/sys_rw.c
index d25a42b7082..957eafb4aa8 100644
--- a/lib/util/sys_rw.c
+++ b/lib/util/sys_rw.c
@@ -293,3 +293,41 @@ ssize_t sys_pwrite_full(int fd, const void *buf, size_t count, off_t off)
 
 	return total_written;
 }
+
+/*******************************************************************
+ A write wrapper that will deal with EINTR and never allow a short
+ write unless the file system returns an error.
+********************************************************************/
+
+ssize_t sys_write_full(int fd, const void *buf, size_t count)
+{
+	ssize_t total_written = 0;
+	const uint8_t *curr_buf = (const uint8_t *)buf;
+	size_t curr_count = count;
+
+	while (curr_count != 0) {
+		ssize_t ret = sys_write(fd,
+					curr_buf,
+					curr_count);
+		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;
+
+		total_written += ret;
+	}
+
+	return total_written;
+}
diff --git a/lib/util/sys_rw.h b/lib/util/sys_rw.h
index 3812159a362..f62d797ec77 100644
--- a/lib/util/sys_rw.h
+++ b/lib/util/sys_rw.h
@@ -41,5 +41,6 @@ ssize_t sys_pread(int fd, void *buf, size_t count, off_t off);
 ssize_t sys_pread_full(int fd, void *buf, size_t count, off_t off);
 ssize_t sys_pwrite(int fd, const void *buf, size_t count, off_t off);
 ssize_t sys_pwrite_full(int fd, const void *buf, size_t count, off_t off);
+ssize_t sys_write_full(int fd, const void *buf, size_t count);
 
 #endif