From: Denys Vlasenko <vda.linux@googlemail.com>
Date: Mon, 5 Sep 2016 13:20:10 +0000 (+0200)
Subject: libbb/xwrite: print errno on "short write" errors
X-Git-Tag: 1_26_0~275
X-Git-Url: https://git.librecmc.org/?a=commitdiff_plain;h=9fd61be191caf78138a50e9d6a465b39318f91c3;p=oweals%2Fbusybox.git

libbb/xwrite: print errno on "short write" errors

Lauri Kasanen:
:: Over at TinyCore, we receive a huge number of questions of the type "I
:: got "short write", what does it mean?". Mostly for the rpi port and when
:: using bb wget.

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
---

diff --git a/libbb/xfuncs_printf.c b/libbb/xfuncs_printf.c
index e9222f690..1b11caf6b 100644
--- a/libbb/xfuncs_printf.c
+++ b/libbb/xfuncs_printf.c
@@ -235,8 +235,16 @@ void FAST_FUNC xwrite(int fd, const void *buf, size_t count)
 {
 	if (count) {
 		ssize_t size = full_write(fd, buf, count);
-		if ((size_t)size != count)
-			bb_error_msg_and_die("short write");
+		if ((size_t)size != count) {
+			/*
+			 * Two cases: write error immediately;
+			 * or some writes succeeded, then we hit an error.
+			 * In either case, errno is set.
+			 */
+			bb_perror_msg_and_die(
+				size >= 0 ? "short write" : "write error"
+			);
+		}
 	}
 }
 void FAST_FUNC xwrite_str(int fd, const char *str)