Re: [PATCH v2] pickles: Add mbr.pk for MBR partition table

[Jose E. Marchesi]

Hi Mohammad.

Very nice :)
OK for master!


> 2021-01-28  Mohammad-Reza Nabipoor  <m.nabipoor@yahoo.com>
>
>       * pickles/mbr.pk: New pickle.
>       * pickles/Makefile.am (dist_pickles_DATA): Add `mbr.pk`.
>       * testsuite/poke.pickles/mbr-test.pk: New test.
>       * testsuite/Makefile.am (EXTRA_DIST): Update.
> ---
>  ChangeLog                          |   7 ++
>  pickles/Makefile.am                |   2 +-
>  pickles/mbr.pk                     | 104 ++++++++++++++++++++++++++
>  testsuite/Makefile.am              |   1 +
>  testsuite/poke.pickles/mbr-test.pk | 116 +++++++++++++++++++++++++++++
>  5 files changed, 229 insertions(+), 1 deletion(-)
>  create mode 100644 pickles/mbr.pk
>  create mode 100644 testsuite/poke.pickles/mbr-test.pk
>
> diff --git a/ChangeLog b/ChangeLog
> index 87f22258..336fcc6a 100644
> --- a/ChangeLog
> +++ b/ChangeLog
> @@ -1,3 +1,10 @@
> +2021-01-28  Mohammad-Reza Nabipoor  <m.nabipoor@yahoo.com>
> +
> +     * pickles/mbr.pk: New pickle.
> +     * pickles/Makefile.am (dist_pickles_DATA): Add `mbr.pk`.
> +     * testsuite/poke.pickles/mbr-test.pk: New test.
> +     * testsuite/Makefile.am (EXTRA_DIST): Update.
> +
>  2021-01-28  Mohammad-Reza Nabipoor  <m.nabipoor@yahoo.com>
>  
>       * libpoke/pkl-gen.pks (struct_writer): Fix bit-offset of mapped
> diff --git a/pickles/Makefile.am b/pickles/Makefile.am
> index d5452e52..7dada3dd 100644
> --- a/pickles/Makefile.am
> +++ b/pickles/Makefile.am
> @@ -2,4 +2,4 @@ picklesdir = $(pkgdatadir)/pickles
>  dist_pickles_DATA = elf.pk ctf.pk leb128.pk bpf.pk btf.pk bmp.pk \
>                      color.pk rgb24.pk id3v1.pk \
>                      dwarf.pk dwarf-common.pk dwarf-frame.pk 
> dwarf-pubnames.pk \
> -                    dwarf-types.pk time.pk argp.pk pktest.pk
> +                    dwarf-types.pk time.pk argp.pk pktest.pk mbr.pk
> diff --git a/pickles/mbr.pk b/pickles/mbr.pk
> new file mode 100644
> index 00000000..4bf5172b
> --- /dev/null
> +++ b/pickles/mbr.pk
> @@ -0,0 +1,104 @@
> +/* mbr.pk - MBR (Master Boot Record) partition table.  */
> +
> +/* Copyright (C) 2021 The poke authors */
> +
> +/* This program is free software: you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License as published by
> + * the Free Software Foundation, either version 3 of the License, or
> + * (at your option) any later version.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + * GNU General Public License for more details.
> + *
> + * You should have received a copy of the GNU General Public License
> + * along with this program.  If not, see <http://www.gnu.org/licenses/>.
> + */
> +
> +/* set_endian(ENDIAN_LITTLE); */
> +
> +type MBR_CHS =
> +  struct
> +  {
> +    type CySec = /* FIXME use unnamed type for `cs` */
> +      struct byte
> +      {
> +        uint<2> cylinder_hi;
> +        uint<6> sector;
> +      };
> +    byte head;
> +    CySec cs;
> +    byte cylinder_lo;
> +
> +    method get_cylinder = uint<10>:
> +      {
> +        return cs.cylinder_hi ::: cylinder_lo;
> +      }
> +    method set_cylinder = (uint<10> c) void:
> +      {
> +        cs.cylinder_hi = c .>> 8;
> +        cylinder_lo = c;
> +      }
> +    method _print = void:
> +      {
> +        printf ("#<head=%u8d,sector=%u6d,cylinder=%u10d>",
> +                head, cs.sector, get_cylinder);
> +      }
> +  };
> +
> +/* MBR Partition Table Entry (PTE)
> + *
> + *  Offset  Size (bytes)  Description
> + *
> + *  0x00    1             Drive attributes (bit 7 set = active or bootable)
> + *  0x01    3             CHS Address of partition start
> + *  0x04    1             Partition type
> + *  0x05    3             CHS address of last partition sector
> + *  0x08    4             LBA of partition start
> + *  0x0C    4             Number of sectors in partition
> + *
> + * ref: https://wiki.osdev.org/MBR_(x86)
> + */
> +type MBR_PTE =
> +  struct
> +  {
> +    struct byte
> +    {
> +      uint<1> active;  /* bootable */
> +      uint<7>;
> +
> +      method _print = void:
> +        {
> +          printf "#<active=%u1d>", active;
> +        }
> +    } attr;
> +    MBR_CHS start_chs;
> +    byte part_type;  /* partition type*/
> +    MBR_CHS end_chs;
> +    uint32 lba;
> +    uint32 sector_count;
> +  };
> +
> +/*
> + *  Offset  Size (bytes)  Description
> + *
> + *  0x000   440           MBR Bootstrap (flat binary executable code)
> + *  0x1B8   4             Optional "Unique Disk ID / Signature"
> + *  0x1BC   2             Optional, reserved 0x0000
> + *  0x1BE   16            First partition table entry
> + *  0x1CE   16            Second partition table entry
> + *  0x1DE   16            Third partition table entry
> + *  0x1EE   16            Fourth partition table entry
> + *  0x1FE   2             (0x55, 0xAA) "Valid bootsector" signature bytes
> + *
> + * ref: https://wiki.osdev.org/MBR_(x86)
> + */
> +type MBR = struct
> +  {
> +    byte[440#B] bootstrap;
> +    uint32 signature;
> +    byte[2] reserved;
> +    MBR_PTE[4] pte;
> +    uint16 magic = 0xaa55UH;
> +  };
> diff --git a/testsuite/Makefile.am b/testsuite/Makefile.am
> index 15c490ce..3139b33e 100644
> --- a/testsuite/Makefile.am
> +++ b/testsuite/Makefile.am
> @@ -481,6 +481,7 @@ EXTRA_DIST = \
>    poke.pickles/pickles.exp \
>    poke.pickles/argp-test.pk \
>    poke.pickles/color-test.pk \
> +  poke.pickles/mbr-test.pk \
>    poke.pickles/id3v1-test.pk \
>    poke.pickles/rgb24-test.pk \
>    poke.pkl/pkl.exp \
> diff --git a/testsuite/poke.pickles/mbr-test.pk 
> b/testsuite/poke.pickles/mbr-test.pk
> new file mode 100644
> index 00000000..962fcc77
> --- /dev/null
> +++ b/testsuite/poke.pickles/mbr-test.pk
> @@ -0,0 +1,116 @@
> +/* mbr-test.pk - Tests for the mbr pickle.  */
> +
> +/* Copyright (C) 2021 The poke authors */
> +
> +/* This program is free software: you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License as published by
> + * the Free Software Foundation, either version 3 of the License, or
> + * (at your option) any later version.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + * GNU General Public License for more details.
> + *
> + * You should have received a copy of the GNU General Public License
> + * along with this program.  If not, see <http://www.gnu.org/licenses/>.
> + */
> +
> +load pktest;
> +load mbr;
> +
> +set_endian(ENDIAN_LITTLE);
> +
> +var data = open ("*data*");
> +
> +var tests = [
> +  PkTest {
> +    name = "magic number",
> +    func = lambda (string name) void:
> +      {
> +        byte[512] @ data : 0#B = byte[512] ();
> +
> +        try
> +          {
> +            var m = MBR @ data : 0#B;
> +
> +            assert(0, "unreachable reached!");
> +          }
> +        catch if E_constraint
> +          {
> +            assert (1, "the magic number cannot be zero!");
> +          }
> +
> +        /* Fix the magic number */
> +        byte[2] @ data : 510#B = [0x55UB, 0xaaUB];
> +
> +        var m = MBR @ data : 0#B;
> +      },
> +  },
> +  PkTest {
> +    name = "CHS",
> +    func = lambda (string name) void:
> +      {
> +        byte[510] @ data : 0#B = byte[510] ();
> +        byte[2] @ data : 510#B = [0x55UB, 0xaaUB];
> +
> +        var m = MBR @ data : 0#B;
> +        var chs = m.pte[0].start_chs;
> +
> +        assert(chs.head == 0);
> +        assert(chs.cs.cylinder_hi == 0);
> +        assert(chs.cs.sector == 0);
> +        assert(chs.cylinder_lo == 0);
> +        assert(chs.get_cylinder == 0);
> +        assert((byte[chs'size] @ data : chs'offset) == [0UB, 0UB, 0UB]);
> +
> +        chs.set_cylinder(0x3ff);
> +        assert(chs.head == 0);
> +        assert(chs.cs.cylinder_hi == 3);
> +        assert(chs.cs.sector == 0);
> +        assert(chs.cylinder_lo == 0xff);
> +        assert(chs.get_cylinder == 0x3ff);
> +        assert((byte[chs'size] @ data : chs'offset) == [0UB, 0xc0UB, 
> 0xffUB]);
> +
> +        chs.cs.cylinder_hi = 1;
> +        assert(chs.head == 0);
> +        assert(chs.cs.cylinder_hi == 1);
> +        assert(chs.cs.sector == 0);
> +        assert(chs.cylinder_lo == 0xff);
> +        assert(chs.get_cylinder == 0x1ff);
> +        assert((byte[chs'size] @ data : chs'offset) == [0UB, 0x40UB, 
> 0xffUB]);
> +
> +        chs.head = 0xa5;
> +        assert(chs.head == 0xa5);
> +        assert(chs.cs.cylinder_hi == 1);
> +        assert(chs.cs.sector == 0);
> +        assert(chs.cylinder_lo == 0xff);
> +        assert(chs.get_cylinder == 0x1ff);
> +        assert((byte[chs'size] @ data : chs'offset) ==
> +               [0xa5UB, 0x40UB, 0xffUB]);
> +
> +        chs.cs.sector = 0xff;  /* Only the 6 LSBs are relevant */
> +        assert(chs.head == 0xa5);
> +        assert(chs.cs.cylinder_hi == 1);
> +        assert(chs.cs.sector == 0x3f);
> +        assert(chs.cylinder_lo == 0xff);
> +        assert(chs.get_cylinder == 0x1ff);
> +        assert((byte[chs'size] @ data : chs'offset) ==
> +               [0xa5UB, 0x7fUB, 0xffUB]);
> +
> +        chs.cylinder_lo = 0x81;
> +        assert(chs.head == 0xa5);
> +        assert(chs.cs.cylinder_hi == 1);
> +        assert(chs.cs.sector == 0x3f);
> +        assert(chs.cylinder_lo == 0x81);
> +        assert(chs.get_cylinder == 0x181);
> +        assert((byte[chs'size] @ data : chs'offset) ==
> +               [0xa5UB, 0x7fUB, 0x81UB]);
> +      },
> +  },
> +];
> +
> +var ec = pktest_run (tests) ? 0 : 1;
> +
> +close(data);
> +exit (ec);