use freopen() and setvbuf() to properly set up stdin/stdout/stderr

1 files changed, 13 insertions, 0 deletions

diff --git a/src/nonstd/__libc_start.c b/src/nonstd/__libc_start.c
index f9fadfd5..c1cf7803 100644
--- a/src/nonstd/__libc_start.c
+++ b/src/nonstd/__libc_start.c
@@ -3,18 +3,31 @@
 
 #include "nonstd/io.h"
 
+#ifdef _POSIX_SOURCE
+#include "unistd.h"
+#else
+#include "nonstd/syscall.h"
+#define isatty(fd) __syscall(__lookup("tty"), fd)
+#endif
+
 void __libc_start(int argc, char **argv)
 {
 	struct __FILE *files = __libc(FILE_STREAMS);
 
 	stdin = files + 0;
 	stdin->fd = 0;
+	freopen(NULL, "r", stdin);
+	setvbuf(stdin, NULL, isatty(0) ? _IOLBF : _IOFBF, BUFSIZ);
 
 	stdout = files + 1;
 	stdout->fd = 1;
+	freopen(NULL, "w", stdout);
+	setvbuf(stdin, NULL, isatty(1) ? _IOLBF : _IOFBF, BUFSIZ);
 
 	stderr = files + 2;
 	stderr->fd = 2;
+	freopen(NULL, "w", stderr);
+	setvbuf(stderr, NULL, _IONBF, 0);
 
 	stdin->next = stdout;
 	stdout->next = stderr;