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shared/install: rework alias check and add test

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This mostly reuses existing checkers used by pid1, so handling of aliases
should be consistent. Hopefully, with the test it'll be clearer what it
happening.

Support for .wants/.requires "aliases" is restored. Those are still used in the
wild quite a bit, so we need to support them.

See https://github.com/systemd/systemd/pull/13119 for a discussion of aliases
with an instance that point to a different template: this is allowed.
This commit is contained in:
Zbigniew Jędrzejewski-Szmek 2019-12-19 16:53:12 +01:00
parent 9a4f9e69e1
commit 3f57bc2267
3 changed files with 203 additions and 38 deletions
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91
src/shared/install.c
View File

@ -1708,36 +1708,67 @@ static int install_info_discover_and_check(
return install_info_may_process(ret ? *ret : NULL, paths, changes, n_changes);
}
int unit_file_verify_alias(const UnitFileInstallInfo *i, const char *dst) {
int unit_file_verify_alias(const UnitFileInstallInfo *i, const char *dst, char **ret_dst) {
_cleanup_free_ char *dst_updated = NULL;
int r;
if (unit_name_is_valid(i->name, UNIT_NAME_TEMPLATE) &&
!unit_name_is_valid(dst, UNIT_NAME_TEMPLATE) &&
!i->default_instance)
return log_error_errno(SYNTHETIC_ERRNO(EINVAL),
"Aliases for templates without DefaultInstance must be templates.");
/* Verify that dst is a valid either a valid alias or a valid .wants/.requires symlink for the target
* unit *i. Return negative on error or if not compatible, zero on success.
*
* ret_dst is set in cases where "instance propagation" happens, i.e. when the instance part is
* inserted into dst. It is not normally set, even on success, so that the caller can easily
* distinguish the case where instance propagation occured.
*/
if (unit_name_is_valid(i->name, UNIT_NAME_INSTANCE | UNIT_NAME_TEMPLATE) &&
!unit_name_is_valid(dst, UNIT_NAME_TEMPLATE | UNIT_NAME_INSTANCE))
return log_error_errno(SYNTHETIC_ERRNO(EINVAL),
"Aliases for template instances must be a templates or template instances containing the instance name.");
const char *path_alias = strrchr(dst, '/');
if (path_alias) {
/* This branch covers legacy Alias= function of creating .wants and .requires symlinks. */
_cleanup_free_ char *dir = NULL;
if (unit_name_is_valid(i->name, UNIT_NAME_INSTANCE | UNIT_NAME_TEMPLATE) &&
unit_name_is_valid(dst, UNIT_NAME_INSTANCE)) {
_cleanup_free_ char *src_inst = NULL, *dst_inst = NULL;
path_alias ++; /* skip over slash */
r = unit_name_to_instance(i->name, &src_inst);
dir = dirname_malloc(dst);
if (!dir)
return log_oom();
if (!endswith(dir, ".wants") && !endswith(dir, ".requires"))
return log_warning_errno(SYNTHETIC_ERRNO(EXDEV),
"Invalid path \"%s\" in alias.", dir);
/* That's the name we want to use for verification. */
r = unit_symlink_name_compatible(path_alias, i->name);
if (r < 0)
return log_error_errno(r, "Failed to verify alias validity: %m");
if (r == 0)
return log_warning_errno(SYNTHETIC_ERRNO(EXDEV),
"Invalid unit %s symlink %s.",
i->name, dst);
} else {
/* If the symlink target has an instance set and the symlink source doesn't, we "propagate
* the instance", i.e. instantiate the symlink source with the target instance. */
if (unit_name_is_valid(dst, UNIT_NAME_TEMPLATE)) {
_cleanup_free_ char *inst = NULL;
r = unit_name_to_instance(i->name, &inst);
if (r < 0)
return log_error_errno(r, "Failed to extract instance name from %s: %m", i->name);
if (r == UNIT_NAME_INSTANCE) {
r = unit_name_replace_instance(dst, inst, &dst_updated);
if (r < 0)
return log_error_errno(r, "Failed to build unit name from %s+%s: %m",
dst, inst);
}
}
r = unit_validate_alias_symlink_and_warn(dst_updated ?: dst, i->name);
if (r < 0)
return r;
r = unit_name_to_instance(dst, &dst_inst);
if (r < 0)
return r;
if (!strstr(dst_inst, src_inst?src_inst:i->default_instance))
return log_error_errno(SYNTHETIC_ERRNO(EINVAL),
"Aliases for template instances must be a templates or template instances containing the instance name.");
}
*ret_dst = TAKE_PTR(dst_updated);
return 0;
}
@ -1757,31 +1788,17 @@ static int install_info_symlink_alias(
assert(config_path);
STRV_FOREACH(s, i->aliases) {
_cleanup_free_ char *alias_path = NULL, *dst = NULL;
_cleanup_free_ char *alias_path = NULL, *dst = NULL, *dst_updated = NULL;
q = install_full_printf(i, *s, &dst);
if (q < 0)
return q;
q = unit_file_verify_alias(i, dst);
q = unit_file_verify_alias(i, dst, &dst_updated);
if (q < 0)
continue;
if (unit_name_is_valid(i->name, UNIT_NAME_INSTANCE) &&
unit_name_is_valid(dst, UNIT_NAME_TEMPLATE)) {
_cleanup_free_ char *s_copy = NULL, *instance = NULL;
q = unit_name_to_instance(i->name, &instance);
if (q < 0)
return q;
q = unit_name_replace_instance(dst, instance, &s_copy);
if (q < 0)
return q;
free_and_replace(dst, s_copy);
}
alias_path = path_make_absolute(dst, config_path);
alias_path = path_make_absolute(dst_updated ?: dst, config_path);
if (!alias_path)
return -ENOMEM;

2
src/shared/install.h
View File

@ -187,7 +187,7 @@ int unit_file_changes_add(UnitFileChange **changes, size_t *n_changes, UnitFileC
void unit_file_changes_free(UnitFileChange *changes, size_t n_changes);
void unit_file_dump_changes(int r, const char *verb, const UnitFileChange *changes, size_t n_changes, bool quiet);
int unit_file_verify_alias(const UnitFileInstallInfo *i, const char *dst);
int unit_file_verify_alias(const UnitFileInstallInfo *i, const char *dst, char **ret_dst);
int unit_file_query_preset(UnitFileScope scope, const char *root_dir, const char *name);

148
src/test/test-install-root.c
View File

@ -1043,6 +1043,152 @@ static void test_preset_multiple_instances(const char *root) {
unit_file_changes_free(changes, n_changes);
}
static void verify_one(
const UnitFileInstallInfo *i,
const char *alias,
int expected,
const char *updated_name) {
int r;
static const UnitFileInstallInfo *last_info = NULL;
_cleanup_free_ char *alias2 = NULL;
if (i != last_info)
log_info("-- %s --", (last_info = i)->name);
r = unit_file_verify_alias(i, alias, &alias2);
log_info_errno(r, "alias %s ← %s: %d/%m (expected %d)%s%s%s",
i->name, alias, r, expected,
alias2 ? " [" : "", alias2 ?: "", alias2 ? "]" : "");
assert(r == expected);
/* This is is test for "instance propagation". This propagation matters mostly for WantedBy= and
* RequiredBy= settings, and less so for Alias=. The only case where it should happen is when we have
* an Alias=alias@.service an instantiated template template@instance. In that case the instance name
* should be propagated into the alias as alias@instance. */
assert(streq_ptr(alias2, updated_name));
}
static void test_verify_alias(void) {
const UnitFileInstallInfo
plain_service = { .name = (char*) "plain.service" },
bare_template = { .name = (char*) "template1@.service" },
di_template = { .name = (char*) "template2@.service",
.default_instance = (char*) "di" },
inst_template = { .name = (char*) "template3@inst.service" },
di_inst_template = { .name = (char*) "template4@inst.service",
.default_instance = (char*) "di" };
verify_one(&plain_service, "alias.service", 0, NULL);
verify_one(&plain_service, "alias.socket", -EXDEV, NULL);
verify_one(&plain_service, "alias@.service", -EXDEV, NULL);
verify_one(&plain_service, "alias@inst.service", -EXDEV, NULL);
verify_one(&plain_service, "foo.target.wants/plain.service", 0, NULL);
verify_one(&plain_service, "foo.target.wants/plain.socket", -EXDEV, NULL);
verify_one(&plain_service, "foo.target.wants/plain@.service", -EXDEV, NULL);
verify_one(&plain_service, "foo.target.wants/service", -EXDEV, NULL);
verify_one(&plain_service, "foo.target.requires/plain.service", 0, NULL);
verify_one(&plain_service, "foo.target.requires/plain.socket", -EXDEV, NULL);
verify_one(&plain_service, "foo.target.requires/plain@.service", -EXDEV, NULL);
verify_one(&plain_service, "foo.target.requires/service", -EXDEV, NULL);
verify_one(&plain_service, "foo.target.conf/plain.service", -EXDEV, NULL);
verify_one(&bare_template, "alias.service", -EXDEV, NULL);
verify_one(&bare_template, "alias.socket", -EXDEV, NULL);
verify_one(&bare_template, "alias@.socket", -EXDEV, NULL);
verify_one(&bare_template, "alias@inst.socket", -EXDEV, NULL);
/* A general alias alias@.service → template1@.service. */
verify_one(&bare_template, "alias@.service", 0, NULL);
/* Only a specific instance is aliased, see the discussion in https://github.com/systemd/systemd/pull/13119. */
verify_one(&bare_template, "alias@inst.service", 0, NULL);
verify_one(&bare_template, "foo.target.wants/plain.service", -EXDEV, NULL);
verify_one(&bare_template, "foo.target.wants/plain.socket", -EXDEV, NULL);
verify_one(&bare_template, "foo.target.wants/plain@.service", -EXDEV, NULL);
/* Name mistmatch: we cannot allow this, because plain@foo.service would be pulled in by foo.taget,
* but would not be resolvable on its own, since systemd doesn't know how to load the fragment. */
verify_one(&bare_template, "foo.target.wants/plain@foo.service", -EXDEV, NULL);
verify_one(&bare_template, "foo.target.wants/template1@foo.service", 0, NULL);
verify_one(&bare_template, "foo.target.wants/service", -EXDEV, NULL);
verify_one(&bare_template, "foo.target.requires/plain.service", -EXDEV, NULL);
verify_one(&bare_template, "foo.target.requires/plain.socket", -EXDEV, NULL);
verify_one(&bare_template, "foo.target.requires/plain@.service", -EXDEV, NULL); /* instance missing */
verify_one(&bare_template, "foo.target.requires/template1@inst.service", 0, NULL);
verify_one(&bare_template, "foo.target.requires/service", -EXDEV, NULL);
verify_one(&bare_template, "foo.target.conf/plain.service", -EXDEV, NULL);
verify_one(&di_template, "alias.service", -EXDEV, NULL);
verify_one(&di_template, "alias.socket", -EXDEV, NULL);
verify_one(&di_template, "alias@.socket", -EXDEV, NULL);
verify_one(&di_template, "alias@inst.socket", -EXDEV, NULL);
verify_one(&di_template, "alias@inst.service", 0, NULL);
verify_one(&di_template, "alias@.service", 0, NULL);
verify_one(&di_template, "alias@di.service", 0, NULL);
verify_one(&di_template, "foo.target.wants/plain.service", -EXDEV, NULL);
verify_one(&di_template, "foo.target.wants/plain.socket", -EXDEV, NULL);
verify_one(&di_template, "foo.target.wants/plain@.service", -EXDEV, NULL);
verify_one(&di_template, "foo.target.wants/plain@di.service", -EXDEV, NULL);
verify_one(&di_template, "foo.target.wants/template2@di.service", 0, NULL);
verify_one(&di_template, "foo.target.wants/service", -EXDEV, NULL);
verify_one(&di_template, "foo.target.requires/plain.service", -EXDEV, NULL);
verify_one(&di_template, "foo.target.requires/plain.socket", -EXDEV, NULL);
verify_one(&di_template, "foo.target.requires/plain@.service", -EXDEV, NULL);
verify_one(&di_template, "foo.target.requires/plain@di.service", -EXDEV, NULL);
verify_one(&di_template, "foo.target.requires/plain@foo.service", -EXDEV, NULL);
verify_one(&di_template, "foo.target.requires/template2@di.service", 0, NULL);
verify_one(&di_template, "foo.target.requires/service", -EXDEV, NULL);
verify_one(&di_template, "foo.target.conf/plain.service", -EXDEV, NULL);
verify_one(&inst_template, "alias.service", -EXDEV, NULL);
verify_one(&inst_template, "alias.socket", -EXDEV, NULL);
verify_one(&inst_template, "alias@.socket", -EXDEV, NULL);
verify_one(&inst_template, "alias@inst.socket", -EXDEV, NULL);
verify_one(&inst_template, "alias@inst.service", 0, NULL);
verify_one(&inst_template, "alias@.service", 0, "alias@inst.service");
verify_one(&inst_template, "alias@di.service", -EXDEV, NULL);
verify_one(&inst_template, "bar.target.wants/plain.service", -EXDEV, NULL);
verify_one(&inst_template, "bar.target.wants/plain.socket", -EXDEV, NULL);
verify_one(&inst_template, "bar.target.wants/plain@.service", -EXDEV, NULL);
verify_one(&inst_template, "bar.target.wants/plain@di.service", -EXDEV, NULL);
verify_one(&inst_template, "bar.target.wants/plain@inst.service", -EXDEV, NULL);
verify_one(&inst_template, "bar.target.wants/template3@foo.service", -EXDEV, NULL);
verify_one(&inst_template, "bar.target.wants/template3@inst.service", 0, NULL);
verify_one(&inst_template, "bar.target.wants/service", -EXDEV, NULL);
verify_one(&inst_template, "bar.target.requires/plain.service", -EXDEV, NULL);
verify_one(&inst_template, "bar.target.requires/plain.socket", -EXDEV, NULL);
verify_one(&inst_template, "bar.target.requires/plain@.service", -EXDEV, NULL);
verify_one(&inst_template, "bar.target.requires/plain@di.service", -EXDEV, NULL);
verify_one(&inst_template, "bar.target.requires/plain@inst.service", -EXDEV, NULL);
verify_one(&inst_template, "bar.target.requires/template3@foo.service", -EXDEV, NULL);
verify_one(&inst_template, "bar.target.requires/template3@inst.service", 0, NULL);
verify_one(&inst_template, "bar.target.requires/service", -EXDEV, NULL);
verify_one(&inst_template, "bar.target.conf/plain.service", -EXDEV, NULL);
/* explicit alias overrides DefaultInstance */
verify_one(&di_inst_template, "alias.service", -EXDEV, NULL);
verify_one(&di_inst_template, "alias.socket", -EXDEV, NULL);
verify_one(&di_inst_template, "alias@.socket", -EXDEV, NULL);
verify_one(&di_inst_template, "alias@inst.socket", -EXDEV, NULL);
verify_one(&di_inst_template, "alias@inst.service", 0, NULL);
verify_one(&di_inst_template, "alias@.service", 0, "alias@inst.service");
verify_one(&di_inst_template, "alias@di.service", -EXDEV, NULL);
verify_one(&di_inst_template, "goo.target.wants/plain.service", -EXDEV, NULL);
verify_one(&di_inst_template, "goo.target.wants/plain.socket", -EXDEV, NULL);
verify_one(&di_inst_template, "goo.target.wants/plain@.service", -EXDEV, NULL);
verify_one(&di_inst_template, "goo.target.wants/plain@di.service", -EXDEV, NULL);
verify_one(&di_inst_template, "goo.target.wants/template4@foo.service", -EXDEV, NULL);
verify_one(&di_inst_template, "goo.target.wants/template4@inst.service", 0, NULL);
verify_one(&di_inst_template, "goo.target.wants/template4@di.service", -EXDEV, NULL);
verify_one(&di_inst_template, "goo.target.wants/service", -EXDEV, NULL);
verify_one(&di_inst_template, "goo.target.requires/plain.service", -EXDEV, NULL);
verify_one(&di_inst_template, "goo.target.requires/plain.socket", -EXDEV, NULL);
verify_one(&di_inst_template, "goo.target.requires/plain@.service", -EXDEV, NULL);
verify_one(&di_inst_template, "goo.target.requires/plain@di.service", -EXDEV, NULL);
verify_one(&di_inst_template, "goo.target.requires/plain@inst.service", -EXDEV, NULL);
verify_one(&di_inst_template, "goo.target.requires/template4@foo.service", -EXDEV, NULL);
verify_one(&di_inst_template, "goo.target.requires/template4@inst.service", 0, NULL);
verify_one(&di_inst_template, "goo.target.requires/service", -EXDEV, NULL);
verify_one(&di_inst_template, "goo.target.conf/plain.service", -EXDEV, NULL);
}
int main(int argc, char *argv[]) {
char root[] = "/tmp/rootXXXXXX";
const char *p;
@ -1080,5 +1226,7 @@ int main(int argc, char *argv[]) {
assert_se(rm_rf(root, REMOVE_ROOT|REMOVE_PHYSICAL) >= 0);
test_verify_alias();
return 0;
}