[parted-devel] [PATCH 1/5] parted: add --fix to "fix" in script mode

[cristian at kleinlabs.eu]

From: Cristian Klein <cristian.klein at elastisys.com>

Use-case: VMs are booted from images that are smaller than their virtual
disk. This means that -- almost by definition -- the secondary GPT
header will be "misplaced", i.e., not at the end of the virtual disk.

Without this patch, parted cannot be used for custom/exotic partitioning
when the VM boots (e.g., in cloud-init's `bootcmd`). Specifically, it
will fail as follows:

```
$ sudo parted --script /dev/vda "mkpart 2 10GB -1"
Warning: Not all of the space available to /dev/vda appears to be used,
you can fix the GPT to use all of the space (an extra 500 blocks) or continue with the current setting?
Error: Unable to satisfy all constraints on the partition.
```

This happens because, in script mode, exceptions are usually not
resolved.

This patch adds `--fix`. This allows exceptions to be automatically
resolved with Fix. As a result, the following command will work:

```
$ sudo parted --fix --script /dev/vda "mkpart 2 10GB -1"
```
---
 parted/parted.c | 8 ++++++--
 parted/ui.c     | 7 +++++++
 parted/ui.h     | 1 +
 3 files changed, 14 insertions(+), 2 deletions(-)

diff --git a/parted/parted.c b/parted/parted.c
index dbd38d0..7f5e2ab 100644
--- a/parted/parted.c
+++ b/parted/parted.c
@@ -115,6 +115,7 @@ static struct option const options[] = {
         {"list",        0, NULL, 'l'},
         {"machine",     0, NULL, 'm'},
         {"script",      0, NULL, 's'},
+        {"fix",         0, NULL, 'f'},
         {"version",     0, NULL, 'v'},
         {"align",       required_argument, NULL, 'a'},
         {"-pretend-input-tty", 0, NULL, PRETEND_INPUT_TTY},
@@ -126,12 +127,14 @@ static const char *const options_help [][2] = {
         {"list",        N_("lists partition layout on all block devices")},
         {"machine",     N_("displays machine parseable output")},
         {"script",      N_("never prompts for user intervention")},
+        {"fix",         N_("in script mode, fix instead of abort when asked")},
         {"version",     N_("displays the version")},
         {"align=[none|cyl|min|opt]", N_("alignment for new partitions")},
         {NULL,          NULL}
 };
 
 int     opt_script_mode = 0;
+int     opt_fix_mode = 0;
 int     pretend_input_tty = 0;
 int     opt_machine_mode = 0;
 int     disk_is_modified = 0;
@@ -2190,7 +2193,7 @@ int     opt, help = 0, list = 0, version = 0, wrong = 0;
 
 while (1)
 {
-        opt = getopt_long (*argc_ptr, *argv_ptr, "hlmsva:",
+        opt = getopt_long (*argc_ptr, *argv_ptr, "hlmsfva:",
                            options, NULL);
         if (opt == -1)
                 break;
@@ -2200,6 +2203,7 @@ while (1)
                 case 'l': list = 1; break;
                 case 'm': opt_machine_mode = 1; break;
                 case 's': opt_script_mode = 1; break;
+                case 'f': opt_fix_mode = 1; break;
                 case 'v': version = 1; break;
                 case 'a':
                   alignment = XARGMATCH ("--align", optarg,
@@ -2216,7 +2220,7 @@ while (1)
 
 if (wrong == 1) {
         fprintf (stderr,
-                 _("Usage: %s [-hlmsv] [-a<align>] [DEVICE [COMMAND [PARAMETERS]]...]\n"),
+                 _("Usage: %s [-hlmsfv] [-a<align>] [DEVICE [COMMAND [PARAMETERS]]...]\n"),
                  program_name);
         return 0;
 }
diff --git a/parted/ui.c b/parted/ui.c
index 73fdcf5..6fad123 100644
--- a/parted/ui.c
+++ b/parted/ui.c
@@ -643,6 +643,13 @@ exception_handler (PedException* ex)
         if (!option_get_next (ex->options, opt))
                 return opt;
 
+        /* script-mode and fix? */
+        int fix_is_an_option = (ex->options & PED_EXCEPTION_FIX);
+        if (opt_script_mode && opt_fix_mode && fix_is_an_option) {
+                printf ("Fixing, due to --fix\n");
+                return PED_EXCEPTION_FIX;
+        }
+
         /* script-mode: don't handle the exception */
         if (opt_script_mode || (!isatty (0) && !pretend_input_tty))
                 return PED_EXCEPTION_UNHANDLED;
diff --git a/parted/ui.h b/parted/ui.h
index 6192ee5..671deb5 100644
--- a/parted/ui.h
+++ b/parted/ui.h
@@ -88,6 +88,7 @@ extern void print_using_dev (PedDevice* dev);
 
 /* in parted.c */
 extern int	opt_script_mode;
+extern int	opt_fix_mode;
 extern int	pretend_input_tty;
 
 extern void print_options_help ();
-- 
2.25.1