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install: allow instantiated units to be enabled via presets

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This patch implements https://github.com/systemd/systemd/issues/9421.

The .preset file now is able to take a rule in the format of:(e.g)
enable foo@.service bar0 bar1 bar2

In the above example, when preset-all is called, all three instances of
foo@bar0.service, foo@bar1.service and foo@bar2.service will be enabled.

When preset is called on a single service(e.g: foo@bar1.service), only
the mentioned one(foo@bar1.service) will be enabled.

Tests are added for future regression.
This commit is contained in:
Ruixin Bao
2018-08-27 23:56:24 +00:00
parent 56663345df
commit 4c9565eea5
2 changed files with 193 additions and 19 deletions
Download Patch File Download Diff File Expand all files Collapse all files
src/shared/install.c
+136 -19
View File
@@ -60,6 +60,7 @@ typedef enum {
typedef struct {
char *pattern;
PresetAction action;
char **instances;
} PresetRule;
typedef struct {
@@ -87,8 +88,10 @@ static inline void presets_freep(Presets *p) {
if (!p)
return;
for (i = 0; i < p->n_rules; i++)
for (i = 0; i < p->n_rules; i++) {
free(p->rules[i].pattern);
strv_free(p->rules[i].instances);
}
free(p->rules);
p->n_rules = 0;
@@ -2755,6 +2758,39 @@ int unit_file_exists(UnitFileScope scope, const LookupPaths *paths, const char *
return 1;
}
static int split_pattern_into_name_and_instances(const char *pattern, char **out_unit_name, char ***out_instances) {
_cleanup_strv_free_ char **instances = NULL;
_cleanup_free_ char *unit_name = NULL;
int r;
assert(pattern);
assert(out_instances);
assert(out_unit_name);
r = extract_first_word(&pattern, &unit_name, NULL, 0);
if (r < 0)
return r;
/* We handle the instances logic when unit name is extracted */
if (pattern) {
/* We only create instances when a rule of templated unit
* is seen. A rule like enable foo@.service a b c will
* result in an array of (a, b, c) as instance names */
if (!unit_name_is_valid(unit_name, UNIT_NAME_TEMPLATE))
return -EINVAL;
instances = strv_split(pattern, WHITESPACE);
if (!instances)
return -ENOMEM;
*out_instances = TAKE_PTR(instances);
}
*out_unit_name = TAKE_PTR(unit_name);
return 0;
}
static int read_presets(UnitFileScope scope, const char *root_dir, Presets *presets) {
_cleanup_(presets_freep) Presets ps = {};
size_t n_allocated = 0;
@@ -2824,15 +2860,20 @@ static int read_presets(UnitFileScope scope, const char *root_dir, Presets *pres
parameter = first_word(l, "enable");
if (parameter) {
char *pattern;
char *unit_name;
char **instances = NULL;
pattern = strdup(parameter);
if (!pattern)
return -ENOMEM;
/* Unit_name will remain the same as parameter when no instances are specified */
r = split_pattern_into_name_and_instances(parameter, &unit_name, &instances);
if (r < 0) {
log_syntax(NULL, LOG_WARNING, *p, n, 0, "Couldn't parse line '%s'. Ignoring.", line);
continue;
}
rule = (PresetRule) {
.pattern = pattern,
.pattern = unit_name,
.action = PRESET_ENABLE,
.instances = instances,
};
}
@@ -2868,15 +2909,71 @@ static int read_presets(UnitFileScope scope, const char *root_dir, Presets *pres
return 0;
}
static int query_presets(const char *name, const Presets presets) {
static int pattern_match_multiple_instances(
const PresetRule rule,
const char *unit_name,
char ***ret) {
_cleanup_free_ char *templated_name = NULL;
int r;
/* If no ret is needed or the rule itself does not have instances
* initalized, we return not matching */
if (!ret || !rule.instances)
return 0;
r = unit_name_template(unit_name, &templated_name);
if (r < 0)
return r;
if (!streq(rule.pattern, templated_name))
return 0;
/* Compose a list of specified instances when unit name is a template */
if (unit_name_is_valid(unit_name, UNIT_NAME_TEMPLATE)) {
_cleanup_free_ char *prefix = NULL;
_cleanup_strv_free_ char **out_strv = NULL;
char **iter;
r = unit_name_to_prefix(unit_name, &prefix);
if (r < 0)
return r;
STRV_FOREACH(iter, rule.instances) {
_cleanup_free_ char *name = NULL;
r = unit_name_build(prefix, *iter, ".service", &name);
if (r < 0)
return r;
r = strv_extend(&out_strv, name);
if (r < 0)
return r;
}
*ret = TAKE_PTR(out_strv);
return 1;
} else {
/* We now know the input unit name is an instance name */
_cleanup_free_ char *instance_name = NULL;
r = unit_name_to_instance(unit_name, &instance_name);
if (r < 0)
return r;
if (strv_find(rule.instances, instance_name))
return 1;
}
return 0;
}
static int query_presets(const char *name, const Presets presets, char ***instance_name_list) {
PresetAction action = PRESET_UNKNOWN;
size_t i;
char **s;
if (!unit_name_is_valid(name, UNIT_NAME_ANY))
return -EINVAL;
for (i = 0; i < presets.n_rules; i++)
if (fnmatch(presets.rules[i].pattern, name, FNM_NOESCAPE) == 0) {
if (pattern_match_multiple_instances(presets.rules[i], name, instance_name_list) > 0 ||
fnmatch(presets.rules[i].pattern, name, FNM_NOESCAPE) == 0) {
action = presets.rules[i].action;
break;
}
@@ -2886,7 +2983,11 @@ static int query_presets(const char *name, const Presets presets) {
log_debug("Preset files don't specify rule for %s. Enabling.", name);
return 1;
case PRESET_ENABLE:
log_debug("Preset files say enable %s.", name);
if (instance_name_list && *instance_name_list)
STRV_FOREACH(s, *instance_name_list)
log_debug("Preset files say enable %s.", *s);
else
log_debug("Preset files say enable %s.", name);
return 1;
case PRESET_DISABLE:
log_debug("Preset files say disable %s.", name);
@@ -2904,7 +3005,7 @@ int unit_file_query_preset(UnitFileScope scope, const char *root_dir, const char
if (r < 0)
return r;
return query_presets(name, presets);
return query_presets(name, presets, NULL);
}
static int execute_preset(
@@ -2964,6 +3065,7 @@ static int preset_prepare_one(
size_t *n_changes) {
_cleanup_(install_context_done) InstallContext tmp = {};
_cleanup_strv_free_ char **instance_name_list = NULL;
UnitFileInstallInfo *i;
int r;
@@ -2979,19 +3081,34 @@ static int preset_prepare_one(
return 0;
}
r = query_presets(name, presets);
r = query_presets(name, presets, &instance_name_list);
if (r < 0)
return r;
if (r > 0) {
r = install_info_discover(scope, plus, paths, name, SEARCH_LOAD|SEARCH_FOLLOW_CONFIG_SYMLINKS,
&i, changes, n_changes);
if (r < 0)
return r;
if (instance_name_list) {
char **s;
STRV_FOREACH(s, instance_name_list) {
r = install_info_discover(scope, plus, paths, *s, SEARCH_LOAD|SEARCH_FOLLOW_CONFIG_SYMLINKS,
&i, changes, n_changes);
if (r < 0)
return r;
r = install_info_may_process(i, paths, changes, n_changes);
if (r < 0)
return r;
}
} else {
r = install_info_discover(scope, plus, paths, name, SEARCH_LOAD|SEARCH_FOLLOW_CONFIG_SYMLINKS,
&i, changes, n_changes);
if (r < 0)
return r;
r = install_info_may_process(i, paths, changes, n_changes);
if (r < 0)
return r;
}
r = install_info_may_process(i, paths, changes, n_changes);
if (r < 0)
return r;
} else
r = install_info_discover(scope, minus, paths, name, SEARCH_FOLLOW_CONFIG_SYMLINKS,
&i, changes, n_changes);