[PATCH] parted: exit nonzero for certain failures already diagnosed as "Error"

[Jim Meyering]

While working on a different GPT-related problem,
I was surprised to see an "Error: ...", yet to see that
parted exited successfully.  This fixes that:

>From f0e91a88107642b17f1c7801d9326460924a1948 Mon Sep 17 00:00:00 2001
From: Jim Meyering <address@hidden>
Date: Thu, 3 Nov 2011 17:57:19 +0100
Subject: [PATCH] parted: exit nonzero for certain failures already diagnosed
 as "Error"

* parted/parted.c (do_print): Do not exit successfully when issuing
an error about an "unrecognised disk label" or when both GPT primary
and backup tables are corrupted.
* tests/t0101-print-empty.sh: Adjust expected exit code to match
new behavior.
* NEWS (Bug fixes): Mention this.
---
 NEWS                       |    5 +++++
 parted/parted.c            |   17 ++++++++++++++---
 tests/t0101-print-empty.sh |    4 ++--
 3 files changed, 21 insertions(+), 5 deletions(-)

diff --git a/NEWS b/NEWS
index af1d957..b043ba1 100644
--- a/NEWS
+++ b/NEWS
@@ -8,6 +8,11 @@ GNU parted NEWS                                    -*- outline 
-*-

 ** Bug fixes

+  parted now exits nonzero for certain failures already diagnosed as "Error".
+  For example, before this change, parted would exit successfully in spite
+  of "Error: ...unrecognised disk label" and "Error:... both GPT primary
+  and backup partition tables are corrupted".
+
   libparted: gpt_disk_duplicate now copies the flags over to the new
   disk object. Previously the flags would be undefined.

diff --git a/parted/parted.c b/parted/parted.c
index b6f89aa..66beba6 100644
--- a/parted/parted.c
+++ b/parted/parted.c
@@ -990,6 +990,7 @@ do_print (PedDevice** dev)
         const char*     name;
         char*           tmp;
         wchar_t*        table_rendered;
+        int ok = 1; /* default to success */

         peek_word = command_line_peek_word ();
         if (peek_word) {
@@ -1015,8 +1016,18 @@ do_print (PedDevice** dev)
                 free (peek_word);
         }

-        if (!has_devices_arg && !has_list_arg)
+        if (!has_devices_arg && !has_list_arg) {
                 disk = ped_disk_new (*dev);
+                /* Returning NULL here is an indication of failure, when in
+                   script mode.  Otherwise (interactive mode) it may indicate
+                   a real error, but it may also indicate that the user
+                   declined when asked to perform some operation.  FIXME:
+                   what this really needs is an API change, but a reliable
+                   exit code is less important in interactive mode.  */
+                if (disk == NULL && opt_script_mode)
+                        ok = 0;
+        }
+
         if (disk &&
             ped_disk_is_flag_available(disk, PED_DISK_CYLINDER_ALIGNMENT))
                 if (!ped_disk_set_flag(disk, PED_DISK_CYLINDER_ALIGNMENT,
@@ -1229,13 +1240,13 @@ do_print (PedDevice** dev)

         ped_disk_destroy (disk);

-        return 1;
+        return ok;

 error_destroy_disk:
         ped_disk_destroy (disk);
         return 0;
 nopt:
-        return 1;
+        return ok;
 }

 static int
diff --git a/tests/t0101-print-empty.sh b/tests/t0101-print-empty.sh
index 3e77850..b8ff5ed 100755
--- a/tests/t0101-print-empty.sh
+++ b/tests/t0101-print-empty.sh
@@ -34,8 +34,8 @@ EOF
 # create 'empty' device
 dd if=/dev/zero of=$dev bs=$(expr 8 '*' $ss) count=1 >/dev/null 2>&1 || fail=1

-# print the empty table
-parted -s $dev unit s print >out 2>&1 || fail=1
+# print the empty table; expect nonzero exit status
+parted -s $dev unit s print >out 2>&1 && fail=1

 # prepare actual and expected output
 mv out o2 && sed "s,^Disk .*/$dev:,Disk .../$dev:,; \
--
1.7.8.rc0.32.g87bf9