[git commit] libbb: Converted safe_read to safe_write format

[Denys Vlasenko]

commit: https://git.busybox.net/busybox/commit/?id=dd4686128290b34d61becaaba88c54d5213f7aa5
branch: https://git.busybox.net/busybox/commit/?id=refs/heads/master

Changed safe_read to be symmetrical to safe_write, it shall
never return EINTR because it calls read multiple times,
the error is considered transient.

function                                             old     new   delta
safe_read                                             44      57     +13

Signed-off-by: Martin Lewis <martin.lewis.x84 at gmail.com>
Signed-off-by: Denys Vlasenko <vda.linux at googlemail.com>
---
 libbb/read.c | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/libbb/read.c b/libbb/read.c
index 5906bc225..a342506a8 100644
--- a/libbb/read.c
+++ b/libbb/read.c
@@ -12,9 +12,17 @@ ssize_t FAST_FUNC safe_read(int fd, void *buf, size_t count)
 {
 	ssize_t n;
 
-	do {
+	for (;;) {
 		n = read(fd, buf, count);
-	} while (n < 0 && errno == EINTR);
+		if (n >= 0 || errno != EINTR)
+			break;
+		/* Some callers set errno=0, are upset when they see EINTR.
+		 * Returning EINTR is wrong since we retry read(),
+		 * the "error" was transient.
+		 */
+		errno = 0;
+		/* repeat the read() */
+	}
 
 	return n;
 }