implement (in a sadly Linux-specific way)

1 files changed, 23 insertions, 2 deletions

diff --git a/src/unistd/ttyname.c b/src/unistd/ttyname.c
index 2d4e3cab..216637c5 100644
--- a/src/unistd/ttyname.c
+++ b/src/unistd/ttyname.c
@@ -1,11 +1,32 @@
 #include "stddef.h"
 #include "sys/types.h"
 #include <unistd.h>
+#include "limits.h"
+#include "stdio.h"
+#include "_unistd.h"
+#include "_syscall.h"
+
+#ifndef PATH_MAX
+#define PATH_MAX _POSIX_PATH_MAX
+#endif
+
+#ifndef readlink
+#define readlink(_path, _buf, _bufsiz) __syscall(__syscall_lookup(readlink), _path, _buf, _bufsiz, 0, 0, 0)
+#endif
 
 char *ttyname(int fildes)
 {
-	(void)fildes;
-	return NULL;
+	char path[PATH_MAX + 1];
+
+	if (!isatty(fildes)) {
+		return NULL;
+	}
+
+	sprintf(path, "/proc/self/fd/%d", fildes);
+	if (readlink(path, __unistd.ttyname, sizeof(__unistd.ttyname)) == -1) {
+		return NULL;
+	}
+	return __unistd.ttyname;
 }
 /*
 POSIX(1)