Bionic lacks ttyname_r; provide a workaround

Signed-off-by: Matt Whitlock <busybox@mattwhitlock.name>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

1 files changed, 19 insertions, 0 deletions

diff --git a/libbb/platform.c b/libbb/platform.c
index 8d90ca4e9..03bbb798b 100644
--- a/libbb/platform.c
+++ b/libbb/platform.c
@@ -194,3 +194,22 @@ ssize_t FAST_FUNC getline(char **lineptr, size_t *n, FILE *stream)
         return len;
 }
 #endif
+
+#ifndef HAVE_TTYNAME_R
+int ttyname_r(int fd, char *buf, size_t buflen)
+{
+        int r;
+        char path[sizeof("/proc/self/fd/%d") + sizeof(int)*3];
+
+        if (!isatty(fd))
+                return errno == EINVAL ? ENOTTY : errno;
+        sprintf(path, "/proc/self/fd/%d", fd);
+        r = readlink(path, buf, buflen);
+        if (r < 0)
+                return errno;
+        if (r >= buflen)
+                return ERANGE;
+        buf[r] = '\0';
+        return 0;
+}
+#endif