[Libguestfs] [PATCH 1/2] mllib: add and use read_first_line_from_file

[Pino Toscano]

Move the read_password_from_file helper in Password to mllib with a more
generic name, and use it in place of the former.

Also, use it in v2v instead of reading the whole file contaning a
password: given that the documentation says that the whole content is
used, there will not be newlines in the password file, so the behaviour
will be preserved. The oly difference is that newline is no more an
acceptable character for passwords, but that is a really unlikely
(if not impossible at all) situation.
---
 customize/password.ml  | 8 +-------
 mllib/common_utils.ml  | 6 ++++++
 mllib/common_utils.mli | 4 ++++
 v2v/cmdline.ml         | 2 +-
 4 files changed, 12 insertions(+), 8 deletions(-)

diff --git a/customize/password.ml b/customize/password.ml
index d91c4b5..111240e 100644
--- a/customize/password.ml
+++ b/customize/password.ml
@@ -60,7 +60,7 @@ and parse_selector_list orig_arg = function
     let pw = parse_selector_list orig_arg rest in
     { pw with pw_locked = true }
   | [ "file"; filename ] ->
-    { pw_password = Password (read_password_from_file filename);
+    { pw_password = Password (read_first_line_from_file filename);
       pw_locked = false }
   | "password" :: password ->
     { pw_password = Password (String.concat ":" password); pw_locked = false }
@@ -71,12 +71,6 @@ and parse_selector_list orig_arg = function
   | _ ->
     error (f_"invalid password selector '%s'; see the man page") orig_arg
 
-and read_password_from_file filename =
-  let chan = open_in filename in
-  let password = input_line chan in
-  close_in chan;
-  password
-
 (* Permissible characters in a salt. *)
 let chars = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789./"
 
diff --git a/mllib/common_utils.ml b/mllib/common_utils.ml
index 083c5d5..f9e8996 100644
--- a/mllib/common_utils.ml
+++ b/mllib/common_utils.ml
@@ -745,3 +745,9 @@ let last_part_of str sep =
     let i = String.rindex str sep in
     Some (String.sub str (i+1) (String.length str - (i+1)))
   with Not_found -> None
+
+let read_first_line_from_file filename =
+  let chan = open_in filename in
+  let line = input_line chan in
+  close_in chan;
+  line
diff --git a/mllib/common_utils.mli b/mllib/common_utils.mli
index 550f37f..16834f7 100644
--- a/mllib/common_utils.mli
+++ b/mllib/common_utils.mli
@@ -181,3 +181,7 @@ val guest_arch_compatible : string -> bool
 
 val last_part_of : string -> char -> string option
 (** Return the last part of a string, after the specified separator. *)
+
+val read_first_line_from_file : string -> string
+(** Read only the first line (i.e. until the first newline character)
+    of a file. *)
diff --git a/v2v/cmdline.ml b/v2v/cmdline.ml
index 705051f..eaf57dc 100644
--- a/v2v/cmdline.ml
+++ b/v2v/cmdline.ml
@@ -259,7 +259,7 @@ read the man page virt-v2v(1).
     match password_file with
     | None -> None
     | Some filename ->
-      let password = read_whole_file filename in
+      let password = read_first_line_from_file filename in
       Some password in
 
   (* Parsing of the argument(s) depends on the input mode. *)
-- 
2.1.0