diff --git a/base/usr/include/stdio.h b/base/usr/include/stdio.h
index e4675ce0..fe85d286 100644
--- a/base/usr/include/stdio.h
+++ b/base/usr/include/stdio.h
@@ -29,7 +29,7 @@ extern size_t fwrite(const void *ptr, size_t size, size_t nmemb, FILE * stream);
 extern int fileno(FILE * stream);
 extern int fflush(FILE * stream);
 
-extern size_t vasprintf(char * buf, const char *fmt, va_list args);
+extern size_t vasprintf(char ** buf, const char *fmt, va_list args);
 extern int    sprintf(char *buf, const char *fmt, ...);
 extern int    fprintf(FILE *stream, char *fmt, ...);
 extern int    printf(char *fmt, ...);
@@ -50,4 +50,6 @@ extern int ungetc(int c, FILE * stream);
 extern int feof(FILE * stream);
 extern void clearerr(FILE * stream);
 
+extern int _fwouldblock(FILE * stream);
+
 #define getc(s) fgetc(s)
diff --git a/libc/stdio/printf.c b/libc/stdio/printf.c
index 7bf36acd..940fa17c 100644
--- a/libc/stdio/printf.c
+++ b/libc/stdio/printf.c
@@ -96,7 +96,7 @@ static void print_hex(unsigned int value, unsigned int width, char * buf, int *
 /*
  * vasprintf()
  */
-size_t vasprintf(char * buf, const char * fmt, va_list args) {
+size_t xvasprintf(char * buf, const char * fmt, va_list args) {
 	int i = 0;
 	char * s;
 	char * b = buf;
@@ -178,33 +178,42 @@ size_t vasprintf(char * buf, const char * fmt, va_list args) {
 	/* Ensure the buffer ends in a null */
 	*b = '\0';
 	return b - buf;
+}
 
+size_t vasprintf(char ** buf, const char * fmt, va_list args) {
+	char * b = malloc(1024);
+	*buf = b;
+	return xvasprintf(b, fmt, args);
 }
 
 int fprintf(FILE * device, char *fmt, ...) {
 	va_list args;
 	va_start(args, fmt);
-	char buffer[1024];
-	vasprintf(buffer, fmt, args);
+	char * buffer;
+	vasprintf(&buffer, fmt, args);
 	va_end(args);
 
-	return fwrite(buffer, 1, strlen(buffer), device);
+	int out = fwrite(buffer, 1, strlen(buffer), device);
+	free(buffer);
+	return out;
 }
 
 int printf(char *fmt, ...) {
 	va_list args;
 	va_start(args, fmt);
-	char buffer[1024];
-	vasprintf(buffer, fmt, args);
+	char * buffer;
+	vasprintf(&buffer, fmt, args);
 	va_end(args);
 
-	return fwrite(buffer, 1, strlen(buffer), stdout);
+	int out = fwrite(buffer, 1, strlen(buffer), stdout);
+	free(buffer);
+	return out;
 }
 
 int sprintf(char * buf, const char *fmt, ...) {
 	va_list args;
 	va_start(args, fmt);
-	int out = vasprintf(buf, fmt, args);
+	int out = xvasprintf(buf, fmt, args);
 	va_end(args);
 	return out;
 }
diff --git a/libc/stdio/stdio.c b/libc/stdio/stdio.c
index 6d9886a4..e73ae1fd 100644
--- a/libc/stdio/stdio.c
+++ b/libc/stdio/stdio.c
@@ -190,6 +190,10 @@ FILE * fdopen(int fd, const char *mode){
 	return out;
 }
 
+int _fwouldblock(FILE * stream) {
+	return !stream->available;
+}
+
 int fclose(FILE * stream) {
 	int out = syscall_close(stream->fd);
 	free(stream->read_buf);