hush: make read builtin interruptible.

function                                             old     new   delta
builtin_read                                         185     471    +286
check_and_run_traps                                  200     262     +62
nonblock_immune_read                                  73     119     +46
sigismember                                            -      44     +44
record_signal                                          -      21     +21
sigisemptyset                                          -      16     +16
...
------------------------------------------------------------------------------
(add/remove: 5/0 grow/shrink: 7/5 up/down: 483/-46)           Total: 437 bytes

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

1 files changed, 5 insertions, 4 deletions

diff --git a/libbb/read_printf.c b/libbb/read_printf.c
index 0e6fbf662..192f83d6e 100644
--- a/libbb/read_printf.c
+++ b/libbb/read_printf.c
@@ -55,19 +55,20 @@
  * which detects EAGAIN and uses poll() to wait on the fd.
  * Thankfully, poll() doesn't care about O_NONBLOCK flag.
  */
-ssize_t FAST_FUNC nonblock_immune_read(int fd, void *buf, size_t count)
+ssize_t FAST_FUNC nonblock_immune_read(int fd, void *buf, size_t count, int loop_on_EINTR)
 {
 	struct pollfd pfd[1];
 	ssize_t n;
 
 	while (1) {
-		n = safe_read(fd, buf, count);
+		n = loop_on_EINTR ? safe_read(fd, buf, count) : read(fd, buf, count);
 		if (n >= 0 || errno != EAGAIN)
 			return n;
 		/* fd is in O_NONBLOCK mode. Wait using poll and repeat */
 		pfd[0].fd = fd;
 		pfd[0].events = POLLIN;
-		safe_poll(pfd, 1, -1); /* note: this pulls in printf */
+		/* note: safe_poll pulls in printf */
+		loop_on_EINTR ? safe_poll(pfd, 1, -1) : poll(pfd, 1, -1);
 	}
 }
 
@@ -90,7 +91,7 @@ char* FAST_FUNC xmalloc_reads(int fd, size_t *maxsz_p)
 			p = buf + sz;
 			sz += 128;
 		}
-		if (nonblock_immune_read(fd, p, 1) != 1) {
+		if (nonblock_immune_read(fd, p, 1, /*loop_on_EINTR:*/ 1) != 1) {
 			/* EOF/error */
 			if (p == buf) { /* we read nothing */
 				free(buf);