failtest: generic cleanup hooks

Each function in the history stores a cleanup function, rather than storing
extra structures.  In particular, we save writes and file offsets using
this.

ccan/failtest/failtest.h

@@ -64,19 +64,21 @@ struct open_call {
 	const char *pathname;
 	int flags;
 	mode_t mode;
+	int dup_fd;
 };
 
 struct pipe_call {
 	int ret;
 	int fds[2];
+	bool closed[2];
 };
 
 struct read_call {
 	ssize_t ret;
+	off_t off;
 	int fd;
 	void *buf;
 	size_t count;
-	off_t off;
 };
 
 struct write_call {
@@ -85,6 +87,10 @@ struct write_call {
 	const void *buf;
 	size_t count;
 	off_t off;
+	off_t old_filelen;
+	off_t saved_len;
+	void *saved_contents;
+	int dup_fd;
 };
 
 struct fcntl_call {
@@ -121,6 +127,8 @@ struct failtest_call {
 	bool fail;
 	/* What we set errno to. */
 	int error;
+	/* How do we clean this up? */
+	void (*cleanup)(void *u);
 	/* The actual call data. */
 	union {
 		struct calloc_call calloc;

ccan/failtest/failtest_override.h

@@ -17,6 +17,10 @@
 #define realloc(ptr, size)					\
 	failtest_realloc((ptr), (size), __FILE__, __LINE__)
 
+#undef free
+#define free(ptr) \
+	failtest_free(ptr)
+
 /* Replacement of I/O. */
 #include <sys/types.h>
 #include <sys/stat.h>

ccan/failtest/failtest_proto.h

@@ -8,6 +8,7 @@ void *failtest_calloc(size_t nmemb, size_t size,
 void *failtest_malloc(size_t size, const char *file, unsigned line);
 void *failtest_realloc(void *ptr, size_t size,
 		       const char *file, unsigned line);
+void failtest_free(void *ptr);
 int failtest_open(const char *pathname,
 		  const char *file, unsigned line, ...);
 int failtest_pipe(int pipefd[2], const char *file, unsigned line);

ccan/failtest/test/run-history.c

@@ -45,8 +45,8 @@ int main(void)
 	realloc_call.ret = realloc(malloc_call.ret, 3);
 	realloc_call.ptr = malloc_call.ret;
 	realloc_call.size = 3;
-	call = add_history(FAILTEST_REALLOC, "run-history.c",
-			   3, &realloc_call);
+	call = add_history(FAILTEST_REALLOC, "run-history.c", 3,
+			   &realloc_call);
 	ok1(call->type == FAILTEST_REALLOC);
 	ok1(strcmp(call->file, "run-history.c") == 0);
 	ok1(call->line == 3);

ccan/failtest/test/run-open.c

@@ -41,7 +41,7 @@ int main(void)
 	ok1(err == EACCES);
 
 	/* Clean up. */
-	close(fd);
+	failtest_close(fd);
 	close(pfd[0]);
 	close(pfd[1]);
 
@@ -59,7 +59,7 @@ int main(void)
 	ok1(read(fd, buf, strlen("Hello world!")) == strlen("Hello world!"));
 	ok1(strcmp(buf, "Hello world!") == 0);
 	/* Clean up. */
-	close(fd);
+	failtest_close(fd);
 	close(pfd[0]);
 	close(pfd[1]);