[PATCH grub] hurdhelper: Add helper to load GNU/Hurd multiboot modules

[Damien Zammit]

This adds a new grub module called hurdhelper.

This module simplifies the loading of hurd multiboot modules
by allowing them to be loaded in one line (in order of loading).

A typical use case would be:

        insmod multiboot
        insmod hurdhelper
        multiboot /boot/gnumach-1.8-486-dbg.gz root=part:2:device:wd0
        hurdmodules /hurd/acpi.static /hurd/pci-arbiter.static 
/hurd/rumpdisk.static \
                    /hurd/ext2fs.static /hurd/exec.static

This could, for example, allow hurd to be booted from the grub shell manually
without remembering and typing dozens of commands.

Signed-off-by: Damien Zammit <damien@zamaudio.com>

---
 grub-core/Makefile.core.def   |   8 ++
 grub-core/loader/hurdhelper.c | 190 ++++++++++++++++++++++++++++++++++++++++++
 grub-core/loader/multiboot.c  |   6 ++
 include/grub/multiboot.h      |   1 +
 include/grub/multiboot2.h     |   1 +
 5 files changed, 206 insertions(+)
 create mode 100644 grub-core/loader/hurdhelper.c

diff --git a/grub-core/Makefile.core.def b/grub-core/Makefile.core.def
index 5212dfab1..240520189 100644
--- a/grub-core/Makefile.core.def
+++ b/grub-core/Makefile.core.def
@@ -1800,6 +1800,14 @@ module = {
 };

 module = {
+  name = hurdhelper;
+  common = loader/hurdhelper.c;
+  enable = x86;
+  enable = i386_pc;
+  enable = i386_multiboot;
+};
+
+module = {
   name = xen_boot;
   arm64 = loader/arm64/xen_boot.c;
   enable = arm64;
diff --git a/grub-core/loader/hurdhelper.c b/grub-core/loader/hurdhelper.c
new file mode 100644
index 000000000..e868ec96a
--- /dev/null
+++ b/grub-core/loader/hurdhelper.c
@@ -0,0 +1,190 @@
+/* hurdhelper.c - helper for loading GNU/Hurd multiboot modules. */
+/*
+ *  GRUB  --  GRand Unified Bootloader
+ *  Copyright (C) 2022  Free Software Foundation, Inc.
+ *
+ *  GRUB 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.
+ *
+ *  GRUB 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 GRUB.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <grub/loader.h>
+#include <grub/command.h>
+#ifdef GRUB_USE_MULTIBOOT2
+#include <grub/multiboot2.h>
+#define GRUB_MULTIBOOT(x) grub_multiboot2_ ## x
+#else
+#include <grub/multiboot.h>
+#define GRUB_MULTIBOOT(x) grub_multiboot_ ## x
+#endif
+#include <grub/cpu/multiboot.h>
+#include <grub/memory.h>
+#include <grub/dl.h>
+#include <grub/err.h>
+
+#define HURD_CMDLINE           
"--multiboot-command-line=${kernel-command-line}"
+#define HURD_HOST_PRIV         "--host-priv-port=${host-port}"
+#define HURD_DEV_MASTER                "--device-master-port=${device-port}"
+
+#define ACPI_TASK              "acpi"
+#define PCI_TASK               "pci-arbiter"
+#define DISK_TASK              "rumpdisk"
+#define FS_TASK                        "ext2fs"
+#define EXEC_TASK              "exec"
+
+#define MAX_MODULES            16
+#define MAX_PARAMS             32
+#define MAX_STRLEN             256
+
+GRUB_MOD_LICENSE ("GPLv3+");
+
+static grub_dl_t my_mod;
+static char *hurd_argv[MAX_MODULES][MAX_PARAMS];
+
+static const char *
+lookup_task (char *arg)
+{
+  char *start;
+  if ((start = grub_strrchr(arg, '/')))
+    start++;
+  else
+    start = arg;
+
+  if (!grub_strncmp(start, ACPI_TASK, 4))
+    return ACPI_TASK;
+  else if (!grub_strncmp(start, PCI_TASK, 11))
+    return PCI_TASK;
+  else if (!grub_strncmp(start, DISK_TASK, 8))
+    return DISK_TASK;
+  else if (!grub_strncmp(start, FS_TASK, 6))
+    return FS_TASK;
+  else if (!grub_strncmp(start, EXEC_TASK, 4))
+    return EXEC_TASK;
+  else
+    return "unknown";
+}
+
+static int
+zalloc_array(char *base[], int members, int size)
+{
+  int i;
+
+  for (i = 0; i < members; i++)
+    {
+      base[i] = grub_zalloc(size);
+      if (!base[i])
+        goto free_and_fail;
+    }
+  return 0;
+
+free_and_fail:
+  for (i--; i > 0; i--)
+    grub_free(base[i]);
+  return 1;
+}
+
+static grub_err_t
+grub_cmd_hurdmodules (grub_command_t cmd __attribute__ ((unused)),
+                     int argc, char *argv[])
+{
+  int err;
+  int i = 0;
+
+  if (argc < 2)
+    return grub_error (GRUB_ERR_BAD_ARGUMENT, N_("minimum two filenames 
expected"));
+
+  /* first module has different args */
+  {
+    err = zalloc_array(hurd_argv[i], 11, MAX_STRLEN);
+    if (err)
+      return grub_error (GRUB_ERR_OUT_OF_MEMORY, "can't create array for 
hurdhelper");
+    grub_snprintf(hurd_argv[i][0], MAX_STRLEN, "%s", argv[i]);
+    grub_snprintf(hurd_argv[i][1], MAX_STRLEN, "%s", lookup_task(argv[i]));
+    grub_snprintf(hurd_argv[i][2], MAX_STRLEN, HURD_HOST_PRIV);
+    grub_snprintf(hurd_argv[i][3], MAX_STRLEN, HURD_DEV_MASTER);
+    if (!grub_strncmp(lookup_task(argv[i]), FS_TASK, 6))
+      {
+        grub_snprintf(hurd_argv[i][4], MAX_STRLEN, HURD_CMDLINE);
+        grub_snprintf(hurd_argv[i][5], MAX_STRLEN, "-T");
+        grub_snprintf(hurd_argv[i][6], MAX_STRLEN, "typed");
+        grub_snprintf(hurd_argv[i][7], MAX_STRLEN, "${root}");
+        grub_snprintf(hurd_argv[i][8], MAX_STRLEN, 
"--exec-server-task=${%s-task}",
+                     lookup_task(argv[i+1]));
+      }
+    else
+      grub_snprintf(hurd_argv[i][8], MAX_STRLEN, "--next-task=${%s-task}", 
lookup_task(argv[i+1]));
+    grub_snprintf(hurd_argv[i][9], MAX_STRLEN, "$(task-create)");
+    grub_snprintf(hurd_argv[i][10], MAX_STRLEN, "$(task-resume)");
+    err = GRUB_MULTIBOOT (cmd_module) (11, hurd_argv[i]);
+    if (err)
+      return err;
+    i++;
+  }
+
+  argc--;
+
+  for (; argc > 1; argc--)
+    {
+      err = zalloc_array(hurd_argv[i], 8, MAX_STRLEN);
+      if (err)
+        return grub_error (GRUB_ERR_OUT_OF_MEMORY, "can't create array for 
hurdhelper");
+      grub_snprintf(hurd_argv[i][0], MAX_STRLEN, "%s", argv[i]);
+      grub_snprintf(hurd_argv[i][1], MAX_STRLEN, "%s", lookup_task(argv[i]));
+      if (!grub_strncmp(lookup_task(argv[i]), FS_TASK, 6))
+        {
+          grub_snprintf(hurd_argv[i][2], MAX_STRLEN, HURD_CMDLINE);
+          grub_snprintf(hurd_argv[i][3], MAX_STRLEN, "-T");
+          grub_snprintf(hurd_argv[i][4], MAX_STRLEN, "typed");
+          grub_snprintf(hurd_argv[i][5], MAX_STRLEN, "${root}");
+          grub_snprintf(hurd_argv[i][6], MAX_STRLEN, 
"--exec-server-task=${%s-task}",
+                       lookup_task(argv[i+1]));
+       }
+      else
+       grub_snprintf(hurd_argv[i][6], MAX_STRLEN, "--next-task=${%s-task}", 
lookup_task(argv[i+1]));
+      grub_snprintf(hurd_argv[i][7], MAX_STRLEN, "$(%s-task=task-create)", 
lookup_task(argv[i]));
+      err = GRUB_MULTIBOOT (cmd_module) (8, hurd_argv[i]);
+      if (err)
+        return err;
+      i++;
+    }
+
+  /* last module has different args */
+  {
+    err = zalloc_array(hurd_argv[i], 3, MAX_STRLEN);
+    if (err)
+      return grub_error (GRUB_ERR_OUT_OF_MEMORY, "can't create array for 
hurdhelper");
+    grub_snprintf(hurd_argv[i][0], MAX_STRLEN, "%s", argv[i]);
+    grub_snprintf(hurd_argv[i][1], MAX_STRLEN, "%s", lookup_task(argv[i]));
+    grub_snprintf(hurd_argv[i][2], MAX_STRLEN, "$(%s-task=task-create)", 
lookup_task(argv[i]));
+    err = GRUB_MULTIBOOT (cmd_module) (3, hurd_argv[i]);
+    if (err)
+      return err;
+  }
+
+  return GRUB_ERR_NONE;
+}
+
+static grub_command_t cmd_hurdmodules;
+
+GRUB_MOD_INIT(hurdhelper)
+{
+  cmd_hurdmodules =
+    grub_register_command ("hurdmodules", grub_cmd_hurdmodules,
+                          0, N_("Load a HURD of multiboot modules."));
+
+  my_mod = mod;
+}
+
+GRUB_MOD_FINI(hurdhelper)
+{
+  grub_unregister_command (cmd_hurdmodules);
+}
diff --git a/grub-core/loader/multiboot.c b/grub-core/loader/multiboot.c
index 94be512c4..e733dfa60 100644
--- a/grub-core/loader/multiboot.c
+++ b/grub-core/loader/multiboot.c
@@ -440,6 +440,12 @@ grub_cmd_module (grub_command_t cmd __attribute__ 
((unused)),
   return GRUB_ERR_NONE;
 }

+grub_err_t
+GRUB_MULTIBOOT (cmd_module) (int argc, char *argv[])
+{
+  return grub_cmd_module (NULL, argc, argv);
+}
+
 static grub_command_t cmd_multiboot, cmd_module;

 GRUB_MOD_INIT(multiboot)
diff --git a/include/grub/multiboot.h b/include/grub/multiboot.h
index d8847f753..2f5eaa951 100644
--- a/include/grub/multiboot.h
+++ b/include/grub/multiboot.h
@@ -46,6 +46,7 @@ void grub_multiboot_free_mbi (void);
 grub_err_t grub_multiboot_init_mbi (int argc, char *argv[]);
 grub_err_t grub_multiboot_add_module (grub_addr_t start, grub_size_t size,
                                      int argc, char *argv[]);
+grub_err_t grub_multiboot_cmd_module (int argc, char *argv[]);
 void grub_multiboot_set_bootdev (void);
 void
 grub_multiboot_add_elfsyms (grub_size_t num, grub_size_t entsize,
diff --git a/include/grub/multiboot2.h b/include/grub/multiboot2.h
index b90aa6989..1f4ce0933 100644
--- a/include/grub/multiboot2.h
+++ b/include/grub/multiboot2.h
@@ -38,6 +38,7 @@ void grub_multiboot2_free_mbi (void);
 grub_err_t grub_multiboot2_init_mbi (int argc, char *argv[]);
 grub_err_t grub_multiboot2_add_module (grub_addr_t start, grub_size_t size,
                                      int argc, char *argv[]);
+grub_err_t grub_multiboot2_cmd_module (int argc, char *argv[]);
 void grub_multiboot2_set_bootdev (void);
 void
 grub_multiboot2_add_elfsyms (grub_size_t num, grub_size_t entsize,
--
2.13.1