X-Git-Url: http://plrg.eecs.uci.edu/git/?p=c11tester.git;a=blobdiff_plain;f=common.cc;h=c190ed37487e44ff37d9145017dad1bd654085d0;hp=f4aa7ecefa023417c7eec4680e38e1c25a5cc13b;hb=222118f318e4788839083a6d99aa7309246243e7;hpb=44118f596eb7cd9b4b0b5037fbbf958db001accc

diff --git a/common.cc b/common.cc
index f4aa7ece..c190ed37 100644
--- a/common.cc
+++ b/common.cc
@@ -1,15 +1,22 @@
 #include <execinfo.h>
 #include <stdio.h>
 #include <stdlib.h>
+#include <unistd.h>
+#include <errno.h>
+#include <fcntl.h>
 
 #include <model-assert.h>
 
 #include "common.h"
 #include "model.h"
 #include "stacktrace.h"
+#include "output.h"
 
 #define MAX_TRACE_LEN 100
 
+/** @brief Model-checker output stream; default to stdout until redirected */
+FILE *model_out = stdout;
+
 #define CONFIG_STACKTRACE
 /** Print a backtrace of the current program state. */
 void print_trace(void)
@@ -24,10 +31,10 @@ void print_trace(void)
 	size = backtrace(array, MAX_TRACE_LEN);
 	strings = backtrace_symbols(array, size);
 
-	printf("\nDumping stack trace (%d frames):\n", size);
+	model_print("\nDumping stack trace (%d frames):\n", size);
 
 	for (i = 0; i < size; i++)
-		printf("\t%s\n", strings[i]);
+		model_print("\t%s\n", strings[i]);
 
 	free(strings);
 #endif /* CONFIG_STACKTRACE */
@@ -40,15 +47,122 @@ void model_print_summary(void)
 
 void assert_hook(void)
 {
-	printf("Add breakpoint to line %u in file %s.\n",__LINE__,__FILE__);
+	model_print("Add breakpoint to line %u in file %s.\n",__LINE__,__FILE__);
 }
 
 void model_assert(bool expr, const char *file, int line)
 {
 	if (!expr) {
-		printf("  [BUG] Program has hit assertion in file %s at line %d\n",
+		char msg[100];
+		sprintf(msg, "Program has hit assertion in file %s at line %d\n",
 				file, line);
-		model->set_assert();
-		model->switch_to_master(NULL);
+		model->assert_user_bug(msg);
+	}
+}
+
+#ifndef CONFIG_DEBUG
+
+static int fd_user_out; /**< @brief File descriptor from which to read user program output */
+
+/**
+ * @brief Setup output redirecting
+ *
+ * Redirects user program's stdout to a pipe so that we can dump it
+ * selectively, when displaying bugs, etc.
+ * Also connects a special file 'model_out' directly to stdout, for printing
+ * data when needed.
+ *
+ * The model-checker can selectively choose to print/hide the user program
+ * output.
+ * @see clear_program_output
+ * @see print_program_output
+ *
+ * Note that the user program's pipe has limited memory, so if a program will
+ * output much data, we will need to buffer it in user-space during execution.
+ * This also means that if ModelChecker decides not to print an execution, it
+ * should promptly clear the pipe.
+ *
+ * This function should only be called once.
+ */
+void redirect_output()
+{
+	int fd;
+
+	/* Save stdout for later use */
+	fd = dup(fileno(stdout));
+	model_out = fdopen(fd, "w");
+
+	/* Redirect program output to a pipe */
+	int pipefd[2];
+	if (pipe(pipefd) < 0) {
+		perror("pipe");
+		exit(EXIT_FAILURE);
+	}
+	fd = dup2(pipefd[1], fileno(stdout)); // STDOUT_FILENO
+	close(pipefd[1]);
+
+	/* Save the "read" side of the pipe for use later */
+	fcntl(pipefd[0], F_SETFL, O_NONBLOCK);
+	fd_user_out = pipefd[0];
+}
+
+/**
+ * @brief Wrapper for reading data to buffer
+ *
+ * Besides a simple read, this handles the subtleties of EOF and nonblocking
+ * input (if fd is O_NONBLOCK).
+ *
+ * @param fd The file descriptor to read.
+ * @param buf Buffer to read to.
+ * @param maxlen Maximum data to read to buffer
+ * @return The length of data read. If zero, then we hit EOF or ran out of data
+ * (non-blocking)
+ */
+static ssize_t read_to_buf(int fd, char *buf, size_t maxlen)
+{
+	ssize_t ret = read(fd, buf, maxlen);
+	if (ret < 0) {
+		if (errno == EAGAIN || errno == EWOULDBLOCK) {
+			return 0;
+		} else {
+			perror("read");
+			exit(EXIT_FAILURE);
+		}
+	}
+	return ret;
+}
+
+/** @brief Dump any pending program output without printing */
+void clear_program_output()
+{
+	fflush(stdout);
+	char buf[200];
+	while (read_to_buf(fd_user_out, buf, sizeof(buf)));
+}
+
+/** @brief Print out any pending program output */
+void print_program_output()
+{
+	char buf[200];
+
+	/* Gather all program output */
+	fflush(stdout);
+
+	/* Read program output pipe and write to (real) stdout */
+	int ret;
+	while (1) {
+		ret = read_to_buf(fd_user_out, buf, sizeof(buf));
+		if (!ret)
+			break;
+		while (ret > 0) {
+			int res = fwrite(buf, 1, ret, model_out);
+			if (res < 0) {
+				errno = ferror(model_out);
+				perror("fwrite");
+				exit(EXIT_FAILURE);
+			}
+			ret -= res;
+		}
 	}
 }
+#endif /* ! CONFIG_DEBUG */