Re: [PATCH 2/5] mkfs: add initial ini format config file parsing support

Darrick J. Wong
2020-10-15T05:46:41Z

On Thu, Oct 15, 2020 at 02:29:22PM +1100, Dave Chinner wrote:
> From: Dave Chinner <dchinner@redhat.com>
>
> Add the framework that will allow the config file to be supplied on
> the CLI and passed to the library that will parse it. This does not
> yet do any option parsing from the config file.
>
> Signed-off-by: Dave Chinner <dchinner@redhat.com>
> ---
> mkfs/Makefile | 2 +-
> mkfs/xfs_mkfs.c | 115 +++++++++++++++++++++++++++++++++++++++++++++++-
> 2 files changed, 115 insertions(+), 2 deletions(-)
>
> diff --git a/mkfs/Makefile b/mkfs/Makefile
> index 31482b08d559..b8805f7e1ea1 100644
> --- a/mkfs/Makefile
> +++ b/mkfs/Makefile
> @@ -11,7 +11,7 @@ HFILES =
> CFILES = proto.c xfs_mkfs.c
>
> LLDLIBS += $(LIBXFS) $(LIBXCMD) $(LIBFROG) $(LIBRT) $(LIBPTHREAD) $(LIBBLKID) \
> - $(LIBUUID)
> + $(LIBUUID) $(LIBINIH)
> LTDEPENDENCIES += $(LIBXFS) $(LIBXCMD) $(LIBFROG)
> LLDFLAGS = -static-libtool-libs
>
> diff --git a/mkfs/xfs_mkfs.c b/mkfs/xfs_mkfs.c
> index 8fe149d74b0a..e84be74fb100 100644
> --- a/mkfs/xfs_mkfs.c
> +++ b/mkfs/xfs_mkfs.c
> @@ -11,6 +11,7 @@
> #include "libfrog/fsgeom.h"
> #include "libfrog/topology.h"
> #include "libfrog/convert.h"
> +#include <ini.h>
>
> #define TERABYTES(count, blog) ((uint64_t)(count) << (40 - (blog)))
> #define GIGABYTES(count, blog) ((uint64_t)(count) << (30 - (blog)))
> @@ -44,6 +45,11 @@ enum {
> B_MAX_OPTS,
> };
>
> +enum {
> + C_OPTFILE = 0,
> + C_MAX_OPTS,
> +};
> +
> enum {
> D_AGCOUNT = 0,
> D_FILE,
> @@ -237,6 +243,28 @@ static struct opt_params bopts = {
> },
> };
>
> +/*
> + * Config file specification. Usage is:
> + *
> + * mkfs.xfs -c file=<name>

I thought it was -c options=/dev/random ?

> + *
> + * A subopt is used for the filename so in future we can extend the behaviour
> + * of the config file (e.g. specified defaults rather than options) if we ever
> + * have a need to do that sort of thing.
> + */
> +static struct opt_params copts = {
> + .name = 'c',
> + .subopts = {
> + [C_OPTFILE] = "options",

Sure looks that way here...

> + },
> + .subopt_params = {
> + { .index = C_OPTFILE,
> + .conflicts = { { NULL, LAST_CONFLICT } },
> + .defaultval = SUBOPT_NEEDS_VAL,
> + },
> + },
> +};
> +
> static struct opt_params dopts = {
> .name = 'd',
> .subopts = {
> @@ -748,6 +776,8 @@ struct cli_params {
> int sectorsize;
> int blocksize;
>
> + char *cfgfile;
> +
> /* parameters that depend on sector/block size being validated. */
> char *dsize;
> char *agsize;
> @@ -862,6 +892,7 @@ usage( void )
> {
> fprintf(stderr, _("Usage: %s\n\
> /* blocksize */ [-b size=num]\n\
> +/* config file */ [-c file=xxx]\n\

...but then we go back to -c file=...

> /* metadata */ [-m crc=0|1,finobt=0|1,uuid=xxx,rmapbt=0|1,reflink=0|1]\n\
> /* data subvol */ [-d agcount=n,agsize=n,file,name=xxx,size=num,\n\
> (sunit=value,swidth=value|su=num,sw=num|noalign),\n\
> @@ -1385,6 +1416,23 @@ block_opts_parser(
> return 0;
> }
>
> +static int
> +cfgfile_opts_parser(
> + struct opt_params *opts,
> + int subopt,
> + char *value,
> + struct cli_params *cli)
> +{
> + switch (subopt) {
> + case C_OPTFILE:
> + cli->cfgfile = getstr(value, opts, subopt);
> + break;
> + default:
> + return -EINVAL;
> + }
> + return 0;
> +}
> +
> static int
> data_opts_parser(
> struct opt_params *opts,
> @@ -1656,6 +1704,7 @@ static struct subopts {
> struct cli_params *cli);
> } subopt_tab[] = {
> { 'b', &bopts, block_opts_parser },
> + { 'c', &copts, cfgfile_opts_parser },
> { 'd', &dopts, data_opts_parser },
> { 'i', &iopts, inode_opts_parser },
> { 'l', &lopts, log_opts_parser },
> @@ -3562,6 +3611,61 @@ check_root_ino(
> }
> }
>
> +/*
> + * INI file format option parser.
> + *
> + * This is called by the file parser library for every valid option it finds in
> + * the config file. The option is already broken down into a
> + * {section,name,value} tuple, so all we need to do is feed it to the correct

XFS, SAX style.

> + * suboption parser function and translate the return value.
> + *
> + * Returns 0 on failure, 1 for success.
> + */
> +static int
> +cfgfile_parse_ini(
> + void *user,
> + const char *section,
> + const char *name,
> + const char *value)
> +{
> + struct cli_params *cli = user;
> +
> + fprintf(stderr, "Ini debug: file %s, section %s, name %s, value %s\n",
> + cli->cfgfile, section, name, value);
> +
> + return 1;
> +}
> +
> +void
> +cfgfile_parse(
> + struct cli_params *cli)
> +{
> + int error;
> +
> + if (!cli->cfgfile)
> + return;
> +
> + error = ini_parse(cli->cfgfile, cfgfile_parse_ini, cli);
> + if (error) {
> + if (error > 0) {
> + fprintf(stderr,
> + _("%s: Unrecognised input on line %d. Aborting.\n"),
> + cli->cfgfile, error);
> + } else if (error == -2) {
> + fprintf(stderr,
> + _("Memory allocation failure parsing %s. Aborting.\n"),
> + cli->cfgfile);
> + } else {
> + fprintf(stderr,
> + _("Unable to open config file %s. Aborting.\n"),
> + cli->cfgfile);

I worry about libinih someday defining more negative error codes. -1 is
"open failed", -2 is OOM, and positive is the line number of a parsing
error, at least according to the documentation.

Maybe we should handle -1 specifically and use the else as a catchall
for unrecognized error codes?

> + }
> + exit(1);
> + }
> + printf(_("Parameters parsed from config file %s successfully\n"),
> + cli->cfgfile);
> +}
> +
> int
> main(
> int argc,
> @@ -3648,13 +3752,14 @@ main(
> memcpy(&cli.sb_feat, &dft.sb_feat, sizeof(cli.sb_feat));
> memcpy(&cli.fsx, &dft.fsx, sizeof(cli.fsx));
>
> - while ((c = getopt(argc, argv, "b:d:i:l:L:m:n:KNp:qr:s:CfV")) != EOF) {
> + while ((c = getopt(argc, argv, "b:c:d:i:l:L:m:n:KNp:qr:s:CfV")) != EOF) {
> switch (c) {
> case 'C':
> case 'f':
> force_overwrite = 1;
> break;
> case 'b':
> + case 'c':
> case 'd':
> case 'i':
> case 'l':
> @@ -3698,6 +3803,14 @@ main(
> } else
> dfile = xi.dname;
>
> + /*
> + * Now we have all the options parsed, we can read in the option file
> + * specified on the command line via "-c file=xxx". Once we have all the

-c options=xxx?

--D

> + * options from this file parsed, we can then proceed with parameter
> + * and bounds checking and making the filesystem.
> + */
> + cfgfile_parse(&cli);
> +
> protostring = setup_proto(protofile);
>
> /*
> --
> 2.28.0
>