[PATCH v2] mkfs: add mkfs config version specifier for the config file

Luis R. Rodriguez
2018-06-18T18:05:26Z

We may opt later to bump this and add new features which we
don't want a v1 parser to use. So peg a version number. We add
a new [global] section dedicated for special configuration file
option specifiers, with the only subtopt supported being 'version'.

The only we support for now is version 1.

Suggested-by: Dave Chinner <david@fromorbit.com>
Signed-off-by: Luis R. Rodriguez <mcgrof@kernel.org>
---

As suggested by Sandeed, added a [global] section which makes the
code easier to read and maintain.

man/man8/mkfs.xfs.8.in | 9 ++++-
mkfs/config.c | 91 ++++++++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 99 insertions(+), 1 deletion(-)

diff --git a/man/man8/mkfs.xfs.8.in b/man/man8/mkfs.xfs.8.in
index cf4bdf827d9c..c86d559ba3e1 100644
--- a/man/man8/mkfs.xfs.8.in
+++ b/man/man8/mkfs.xfs.8.in
@@ -965,12 +965,19 @@ option follow a simple ini-style format as shown below.
Available options consist of a small subset of the parameters available
via the
.BR mkfs.xfs (8)
-command line.
+command line. All configuration files must start with an annotation of
+the configuration file format, specified in the global section with the keyword
+.B version
+and the only supported version format is 1.
Currently all default parameters can only be either enabled or disabled,
with a value of 1 to enable or 0 to disable.
See below for a list of all supported configuration parameters and their
current built-in default settings.
.PP
+.BI [global]
+.br
+.BI version=1
+.PP
.BI [data]
.br
.BI noalign=0
diff --git a/mkfs/config.c b/mkfs/config.c
index 835adc45f02d..4bb371d6b1e8 100644
--- a/mkfs/config.c
+++ b/mkfs/config.c
@@ -32,6 +32,8 @@
* We only provide definitions for what we currently support parsing.
*/

+static uint64_t mkfs_config_version;
+
enum data_subopts {
D_NOALIGN = 0,
};
@@ -42,6 +44,14 @@ enum inode_subopts {
I_SPINODES,
};

+/*
+ * These are not part of the defaults but rather global generic configuration
+ * file options.
+ */
+enum global_subopts {
+ G_VERSION = 0,
+};
+
enum log_subopts {
L_LAZYSBCNTR = 0,
};
@@ -122,6 +132,24 @@ inode_config_parser(
return -1;
}

+static int
+global_config_parser(
+ struct mkfs_default_params *dft,
+ int psubopt,
+ uint64_t value)
+{
+ enum global_subopts subopt = psubopt;
+
+ switch (subopt) {
+ case G_VERSION:
+ if (value != 1)
+ return -1;
+ mkfs_config_version = value;
+ return 0;
+ }
+ return -1;
+}
+
static int
log_config_parser(
struct mkfs_default_params *dft,
@@ -234,6 +262,14 @@ struct confopts {
},
.parser = inode_config_parser,
},
+ {
+ .name = "global",
+ .subopts = {
+ [G_VERSION] = "version",
+ NULL
+ },
+ .parser = global_config_parser,
+ },
{
.name = "log",
.subopts = {
@@ -287,6 +323,24 @@ get_confopts(
return NULL;
}

+static bool config_version_set(void)
+{
+ /* cannot fail */
+ struct confopts *opts = get_confopts("global");
+
+ return opts->seen;
+}
+
+static uint64_t config_version(void)
+{
+ /* cannot fail */
+ struct confopts *opts = get_confopts("global");
+
+ if (!opts->seen)
+ return 0;
+ return mkfs_config_version;
+}
+
enum parse_line_type {
PARSE_COMMENT = 0,
PARSE_EMPTY,
@@ -379,6 +433,32 @@ parse_get_line_type(
return PARSE_INVALID;
}

+static bool
+check_version_supported(
+ void)
+{
+ uint64_t version = config_version();
+
+ if (!version) {
+ fprintf(stderr,
+_("Version for configuration file not specified\n"));
+ goto out;
+ }
+
+ if (version != 1) {
+ errno = EOPNOTSUPP;
+ fprintf(stderr,
+_("Only version 1 supported, you specified version %lu\n"), version);
+ goto out;
+ }
+
+ return true;
+
+out:
+ errno = EOPNOTSUPP;
+ return false;
+}
+
static int
parse_config_stream(
struct mkfs_default_params *dft,
@@ -420,6 +500,7 @@ parse_config_stream(
config_file, lineno, line);
goto out;
case PARSE_SECTION:
+
confopt = get_confopts(tag);
if (!confopt) {
fprintf(stderr,
@@ -451,6 +532,13 @@ _("No section specified yet on line %s:%zu : %s\n"),
goto out_free_tag;
}

+ if (!config_version_set() &&
+ strcmp(confopt->name, "global") != 0) {
+ fprintf(stderr,
+_("A global section with a version set was not detected and must be set first\n"));
+ goto out_free_tag;
+ }
+
/*
* We re-use the line buffer allocated by getline(),
* however line must be kept pointing to its original
@@ -486,6 +574,9 @@ _("Error parsing line %s:%zu : %s\n"),
goto out;
}

+ if (!check_version_supported())
+ goto out;
+
break;
}
free(line);
--
2.16.3