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discover/grub2: add support for grub2-style path specifiers in resources
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This change incorporates the grub2-style (device)/path specifiers in the
grub2 parser's resource code. This allows the boot option paths to use
device-specific references.

Device names are looked-up using the UUID and kernel IDs, but with the
lookup logic specific to a new function (grub2_lookup_device), so that
can be extended in a future change.

Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
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@jk-ozlabs
jk-ozlabs committed Nov 29, 2019
1 parent 51f7117 commit 9fc2ac6
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Showing 6 changed files with 147 additions and 37 deletions.
19 changes: 8 additions & 11 deletions discover/grub2/blscfg.c
View file
Expand Up @@ -166,7 +166,6 @@ static void bls_finish(struct conf_context *conf)
struct discover_context *dc = conf->dc;
struct discover_boot_option *opt = state->opt;
struct boot_option *option = opt->option;
const char *root;
char *filename;

if (!state->image) {
Expand All @@ -192,23 +191,21 @@ static void bls_finish(struct conf_context *conf)
else
option->name = talloc_strdup(option, state->image);

root = script_env_get(state->script, "root");

opt->boot_image = create_grub2_resource(opt, conf->dc->device,
root, state->image);
opt->boot_image = create_grub2_resource(state->script, opt,
state->image);

if (state->initrd)
opt->initrd = create_grub2_resource(opt, conf->dc->device,
root, state->initrd);
opt->initrd = create_grub2_resource(state->script, opt,
state->initrd);

if (state->dtb)
opt->dtb = create_grub2_resource(opt, conf->dc->device,
root, state->dtb);
opt->dtb = create_grub2_resource(state->script, opt,
state->dtb);

char* args_sigfile_default = talloc_asprintf(opt,
"%s.cmdline.sig", state->image);
opt->args_sig_file = create_grub2_resource(opt, conf->dc->device,
root, args_sigfile_default);
opt->args_sig_file = create_grub2_resource(state->script, opt,
args_sigfile_default);
talloc_free(args_sigfile_default);

option->is_default = option_is_default(state, option);
Expand Down
15 changes: 4 additions & 11 deletions discover/grub2/builtins.c
View file
Expand Up @@ -46,7 +46,6 @@ static int builtin_linux(struct grub2_script *script,
int argc, char *argv[])
{
struct discover_boot_option *opt = script->opt;
const char *root;
int i;

if (!opt) {
Expand All @@ -61,10 +60,7 @@ static int builtin_linux(struct grub2_script *script,
return -1;
}

root = script_env_get(script, "root");

opt->boot_image = create_grub2_resource(opt, script->ctx->device,
root, argv[1]);
opt->boot_image = create_grub2_resource(script, opt, argv[1]);
opt->option->boot_args = NULL;

if (argc > 2)
Expand All @@ -77,8 +73,8 @@ static int builtin_linux(struct grub2_script *script,

char* args_sigfile_default = talloc_asprintf(opt,
"%s.cmdline.sig", argv[1]);
opt->args_sig_file = create_grub2_resource(opt, script->ctx->device,
root, args_sigfile_default);
opt->args_sig_file = create_grub2_resource(script, opt,
args_sigfile_default);
talloc_free(args_sigfile_default);
return 0;
}
Expand All @@ -88,7 +84,6 @@ static int builtin_initrd(struct grub2_script *script,
int argc, char *argv[])
{
struct discover_boot_option *opt = script->opt;
const char *root;

if (!opt) {
pb_log("grub2 syntax error: 'initrd' statement outside "
Expand All @@ -102,9 +97,7 @@ static int builtin_initrd(struct grub2_script *script,
return -1;
}

root = script_env_get(script, "root");
opt->initrd = create_grub2_resource(opt, script->ctx->device,
root, argv[1]);
opt->initrd = create_grub2_resource(script, opt, argv[1]);

return 0;
}
Expand Down
56 changes: 44 additions & 12 deletions discover/grub2/grub2.c
View file
Expand Up @@ -33,32 +33,65 @@ static const char *const grub2_conf_files[] = {
NULL
};

static struct discover_device *grub2_lookup_device(
struct device_handler *handler, const char *desc)
{
struct discover_device *dev;

if (!desc || !*desc)
return NULL;

dev = device_lookup_by_id(handler, desc);
if (dev)
return dev;

/* for now, only lookup by UUID */
dev = device_lookup_by_uuid(handler, desc);
if (dev)
return dev;

return NULL;
}

/* we use slightly different resources for grub2 */
struct resource *create_grub2_resource(struct discover_boot_option *opt,
struct discover_device *orig_device,
const char *root, const char *path)
struct resource *create_grub2_resource(struct grub2_script *script,
struct discover_boot_option *opt,
const char *path)
{
struct discover_device *dev;
struct grub2_file *file;
struct resource *res;
const char *root;

if (strstr(path, "://")) {
struct pb_url *url = pb_url_parse(opt, path);
if (url)
return create_url_resource(opt, url);
}

file = grub2_parse_file(script, path);
if (!file)
return NULL;

res = talloc(opt, struct resource);
root = script_env_get(script, "root");

if (root) {
file = talloc(res, struct grub2_file);
if (!file->dev && root && strlen(root))
file->dev = talloc_strdup(file, root);
file->path = talloc_strdup(file, path);

res->resolved = false;
res->info = file;
/* if we don't have a device specified, or the lookup succeeds now,
* then we can resolve the resource right away */
if (file->dev)
dev = grub2_lookup_device(script->ctx->handler, file->dev);
else
dev = script->ctx->device;

} else
resolve_resource_against_device(res, orig_device, path);
if (dev) {
resolve_resource_against_device(res, dev, file->path);
} else {
res->resolved = false;
res->info = talloc_steal(opt, file);
}

return res;
}
Expand All @@ -71,8 +104,7 @@ bool resolve_grub2_resource(struct device_handler *handler,

assert(!res->resolved);

dev = device_lookup_by_uuid(handler, file->dev);

dev = grub2_lookup_device(handler, file->dev);
if (!dev)
return false;

Expand Down
5 changes: 2 additions & 3 deletions discover/grub2/grub2.h
View file
Expand Up @@ -191,9 +191,8 @@ void script_register_function(struct grub2_script *script,
void register_builtins(struct grub2_script *script);

/* resources */
struct resource *create_grub2_resource(struct discover_boot_option *opt,
struct discover_device *orig_device,
const char *root, const char *path);
struct resource *create_grub2_resource(struct grub2_script *script,
struct discover_boot_option *opt, const char *path);

bool resolve_grub2_resource(struct device_handler *handler,
struct resource *res);
Expand Down
1 change: 1 addition & 0 deletions test/parser/Makefile.am
View file
Expand Up @@ -32,6 +32,7 @@ parser_TESTS = \
test/parser/test-grub2-search-args \
test/parser/test-grub2-search-uuid \
test/parser/test-grub2-search-label \
test/parser/test-grub2-devpath \
test/parser/test-grub2-load-env \
test/parser/test-grub2-save-env \
test/parser/test-grub2-save-env-dash-f \
Expand Down
88 changes: 88 additions & 0 deletions test/parser/test-grub2-devpath.c
View file
@@ -0,0 +1,88 @@
/* check grub2 device+path string parsing */

#include "parser-test.h"

#if 0 /* PARSER_EMBEDDED_CONFIG */

# local
menuentry a {
linux /vmlinux
}

# local, specified by root env var
root=00000000-0000-0000-0000-000000000001
menuentry b {
linux /vmlinux
}

# remote, specified by root env var
root=00000000-0000-0000-0000-000000000002
menuentry c {
linux /vmlinux
}

# local, full dev+path spec
menuentry d {
linux (00000000-0000-0000-0000-000000000001)/vmlinux
}

# remote, full dev+path spec
menuentry e {
linux (00000000-0000-0000-0000-000000000002)/vmlinux
}

# invalid: incomplete dev+path spec
menuentry f {
linux (00000000-0000-0000-0000-000000000001
}

# invalid: no path
menuentry g {
linux (00000000-0000-0000-0000-000000000001)
}


#endif

void run_test(struct parser_test *test)
{
struct discover_device *dev1, *dev2;
struct discover_boot_option *opt;
struct discover_context *ctx;

ctx = test->ctx;

/* set local uuid */
dev1 = test->ctx->device;
dev1->uuid = "00000000-0000-0000-0000-000000000001";

dev2 = test_create_device(test, "extdev");
dev2->uuid = "00000000-0000-0000-0000-000000000002";
device_handler_add_device(ctx->handler, dev2);

test_read_conf_embedded(test, "/grub/grub.cfg");

test_run_parser(test, "grub2");

check_boot_option_count(ctx, 5);

opt = get_boot_option(ctx, 0);
check_name(opt, "a");
check_resolved_local_resource(opt->boot_image, dev1, "/vmlinux");

opt = get_boot_option(ctx, 1);
check_name(opt, "b");
check_resolved_local_resource(opt->boot_image, dev1, "/vmlinux");

opt = get_boot_option(ctx, 2);
check_name(opt, "c");
check_resolved_local_resource(opt->boot_image, dev2, "/vmlinux");

opt = get_boot_option(ctx, 3);
check_name(opt, "d");
check_resolved_local_resource(opt->boot_image, dev1, "/vmlinux");

opt = get_boot_option(ctx, 4);
check_name(opt, "e");
check_resolved_local_resource(opt->boot_image, dev2, "/vmlinux");
}

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