[klibc] [BUILTIN] Continue after EINTR in read(1) with no pending

signals

The recent introduction of SIGCHLD trapping broke read(1) as
each SIGCHLD may cause read(1) to return prematurely.  Now if
we did have a trap for SIGCHLD read(1) should actually do this.
However, returning when SIGCHLD isn't trapped is wrong.

This patch fixes this by checking for EINTR and pendingsigs in
read(1).

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
[ merge fixups -maks ]
Signed-off-by: maximilian attems <max@stro.at>

1 files changed, 11 insertions, 2 deletions

diff --git a/usr/dash/miscbltin.c b/usr/dash/miscbltin.c
index 50da2529c1319..c6c5d55c531d5 100644
--- a/usr/dash/miscbltin.c
+++ b/usr/dash/miscbltin.c
@@ -58,6 +58,7 @@
 #include "main.h"
 #include "expand.h"
 #include "parser.h"
+#include "trap.h"
 
 #undef rflag
 
@@ -213,9 +214,16 @@ readcmd(int argc, char **argv)
 				break; /* Timeout! */
 			}
 		}
-		if (read(0, &c, 1) != 1) {
-			status = 1;
+		switch (read(0, &c, 1)) {
+		case 1:
 			break;
+		default:
+			if (errno == EINTR && !pendingsigs)
+				continue;
+				/* fall through */
+		case 0:
+			status = 1;
+			goto out;
 		}
 		if (c == '\0')
 			continue;
@@ -236,6 +244,7 @@ put:
 resetbs:
 		backslash = 0;
 	}
+out:
 	STACKSTRNUL(p);
 	readcmd_handle_line(stackblock(), ap, p + 1 - (char *)stackblock());
 	return status;