testsuite: split out function to compare outputs exactly

Move functionality to compare the exact output to a separate function
and allocate one buffer per output/match pair. This will allow us to
extend this to allow other types of comparisons. Since now we are using
heap-allocated buffer, keep the buffer allocation to the caller, so we
don't have to allocate and free it on every invocation. It also avoids
the different comparison functions to have to deal with it.

1 files changed, 70 insertions, 54 deletions

diff --git a/testsuite/testsuite.c b/testsuite/testsuite.c
index 8512b56..508bbd3 100644
--- a/testsuite/testsuite.c
+++ b/testsuite/testsuite.c
@@ -290,13 +290,64 @@ static int check_activity(int fd, bool activity,  const char *path,
 	return -1;
 }
 
-static inline bool test_run_parent_check_outputs(const struct test *t,
-			int fdout, int fderr, int fdmonitor, pid_t child)
+#define BUFSZ 4096
+struct buffer {
+	char buf[BUFSZ];
+};
+
+/* read fd and fd_match, checking they match exactly */
+static bool cmpbuf_exact(const struct test *t, const char *prefix,
+			 int fd, int fd_match, struct buffer *buf,
+			 struct buffer *buf_match)
+{
+	int r, rmatch, done = 0;
+
+	r = read(fd, buf->buf, sizeof(buf->buf) - 1);
+	if (r <= 0)
+		/* try again later */
+		return true;
+
+	/* read as much data from fd_match as we read from fd */
+	for (;;) {
+		rmatch = read(fd_match, buf_match->buf + done, r - done);
+		if (rmatch == 0)
+			break;
+
+		if (rmatch < 0) {
+			if (errno == EINTR)
+				continue;
+			ERR("could not read match fd %d\n", fd_match);
+			return false;
+		}
+
+		done += rmatch;
+	}
+
+	buf->buf[r] = '\0';
+	buf_match->buf[r] = '\0';
+
+	if (t->print_outputs)
+		printf("%s: %s\n", prefix, buf->buf);
+
+	if (!streq(buf->buf, buf_match->buf)) {
+		ERR("Outputs do not match on %s:\n", prefix);
+		ERR("correct:\n%s\n", buf_match->buf);
+		ERR("wrong:\n%s\n", buf->buf);
+		return false;
+	}
+
+	return true;
+}
+
+static bool test_run_parent_check_outputs(const struct test *t,
+					  int fdout, int fderr, int fdmonitor,
+					  pid_t child)
 {
 	struct epoll_event ep_outpipe, ep_errpipe, ep_monitor;
 	int err, fd_ep, fd_matchout = -1, fd_matcherr = -1;
 	bool fd_activityout = false, fd_activityerr = false;
 	unsigned long long end_usec, start_usec;
+	_cleanup_free_ struct buffer *buf_out = NULL, *buf_err = NULL;
 
 	fd_ep = epoll_create1(EPOLL_CLOEXEC);
 	if (fd_ep < 0) {
@@ -320,6 +371,7 @@ static inline bool test_run_parent_check_outputs(const struct test *t,
 			ERR("could not add fd to epoll: %m\n");
 			goto out;
 		}
+		buf_out = calloc(2, sizeof(*buf_out));
 	} else
 		fdout = -1;
 
@@ -340,6 +392,7 @@ static inline bool test_run_parent_check_outputs(const struct test *t,
 			ERR("could not add fd to epoll: %m\n");
 			goto out;
 		}
+		buf_err = calloc(2, sizeof(*buf_err));
 	} else
 		fderr = -1;
 
@@ -374,76 +427,39 @@ static inline bool test_run_parent_check_outputs(const struct test *t,
 		}
 
 		for (i = 0;  i < fdcount; i++) {
-			int *fd = ev[i].data.ptr;
+			int fd = *(int *)ev[i].data.ptr;
 
 			if (ev[i].events & EPOLLIN) {
-				ssize_t r, done = 0;
-				char buf[4096];
-				char bufmatch[4096];
 				int fd_match;
+				struct buffer *buf, *buf_match;
+				const char *prefix;
 
-				/*
-				 * compare the output from child with the one
-				 * saved as correct
-				 */
-
-				r = read(*fd, buf, sizeof(buf) - 1);
-				if (r <= 0)
-					continue;
-
-				if (*fd == fdout) {
+				if (fd == fdout) {
 					fd_match = fd_matchout;
+					buf = buf_out;
 					fd_activityout = true;
-				} else if (*fd == fderr) {
+					prefix = "STDOUT";
+				} else if (fd == fderr) {
 					fd_match = fd_matcherr;
+					buf = buf_err;
 					fd_activityerr = true;
+					prefix = "STDERR";
 				} else {
 					ERR("Unexpected activity on monitor pipe\n");
 					err = -EINVAL;
 					goto out;
 				}
 
-				for (;;) {
-					int rmatch = read(fd_match,
-						bufmatch + done, r - done);
-					if (rmatch == 0)
-						break;
-
-					if (rmatch < 0) {
-						if (errno == EINTR)
-							continue;
-						err = -errno;
-						ERR("could not read match fd %d\n",
-								fd_match);
-						goto out;
-					}
-
-					done += rmatch;
-				}
+				buf_match = buf + 1;
 
-				buf[r] = '\0';
-				bufmatch[r] = '\0';
-
-				if (t->print_outputs)
-					printf("%s: %s\n",
-					       fd_match == fd_matchout ? "STDOUT:" : "STDERR:",
-					       buf);
-
-				if (!streq(buf, bufmatch)) {
-					ERR("Outputs do not match on %s:\n",
-						fd_match == fd_matchout ? "STDOUT" : "STDERR");
-					ERR("correct:\n%s\n", bufmatch);
-					ERR("wrong:\n%s\n", buf);
-					err = -1;
+				if (!cmpbuf_exact(t, prefix,  fd, fd_match,
+						  buf, buf_match))
 					goto out;
-				}
 			} else if (ev[i].events & EPOLLHUP) {
-				if (epoll_ctl(fd_ep, EPOLL_CTL_DEL,
-							*fd, NULL) < 0) {
-					ERR("could not remove fd %d from epoll: %m\n",
-									*fd);
+				if (epoll_ctl(fd_ep, EPOLL_CTL_DEL, fd, NULL) < 0) {
+					ERR("could not remove fd %d from epoll: %m\n", fd);
 				}
-				*fd = -1;
+				*(int *)ev[i].data.ptr = -1;
 			}
 		}
 	}