Initial QSfera import

Server/vendor/github.com/amoghe/go-crypt/crypt_r.go

@@ -0,0 +1,78 @@
+// +build linux
+
+// Package crypt provides wrappers around functions available in crypt.h
+//
+// It wraps around the GNU specific extension (crypt_r) when it is available
+// (i.e. where GOOS=linux). This makes the go function reentrant (and thus
+// callable from concurrent goroutines).
+package crypt
+
+import (
+	"syscall"
+	"unsafe"
+)
+
+/*
+#cgo LDFLAGS: -lcrypt
+
+#define _GNU_SOURCE
+
+#include <stdlib.h>
+#include <string.h>
+#include <crypt.h>
+
+char *gnu_ext_crypt(char *pass, char *salt) {
+  char *enc = NULL;
+  char *ret = NULL;
+  struct crypt_data data;
+  data.initialized = 0;
+
+  enc = crypt_r(pass, salt, &data);
+  if(enc == NULL) {
+    return NULL;
+  }
+
+  ret = (char *)malloc(strlen(enc)+1); // for trailing null
+  strncpy(ret, enc, strlen(enc));
+  ret[strlen(enc)]= '\0'; // paranoid
+
+  return ret;
+}
+*/
+import "C"
+
+// Crypt provides a wrapper around the glibc crypt_r() function.
+// For the meaning of the arguments, refer to the package README.
+func Crypt(pass, salt string) (string, error) {
+	c_pass := C.CString(pass)
+	defer C.free(unsafe.Pointer(c_pass))
+
+	c_salt := C.CString(salt)
+	defer C.free(unsafe.Pointer(c_salt))
+
+	c_enc, err := C.gnu_ext_crypt(c_pass, c_salt)
+	if c_enc == nil {
+		return "", err
+	}
+	defer C.free(unsafe.Pointer(c_enc))
+
+	// From the crypt(3) man-page. Upon error, crypt_r writes an invalid
+	// hashed passphrase to the output field of their data argument, and
+	// crypt writes an invalid hash to its static storage area. This
+	// string will be shorter than 13 characters, will begin with a ‘*’,
+	// and will not compare equal to setting.
+	hash := C.GoString(c_enc)
+	if len(hash) > 0 && hash[0] == '*' {
+		// Make sure we acutally return an error, musl e.g. does not
+		// set errno in all cases here.
+		if err == nil {
+			err = syscall.EINVAL
+		}
+		return "", err
+	}
+
+	// Return nil error if the string is non-nil.
+	// As per the errno.h manpage, functions are allowed to set errno
+	// on success. Caller should ignore errno on success.
+	return hash, nil
+}