systemd-analyze: option to exit with an error when 'verify' fails

The commit introduces a callback invoked from log_syntax_internal.
Use it from systemd-analyze to gather a list of units that contain
syntax warnings. A new command line option is added to make use of this.

The new option --recursive-errors takes in three possible modes:

1. yes - which is the default. systemd-analyze exits with an error when syntax warnings arise during verification of the
	 specified units or any of their dependencies.
3. no - systemd-analyze exits with an error when syntax warnings arise during verification of only the selected unit.
	Analyzing and loading any dependencies will be skipped.
4. one - systemd-analyze exits with an error when syntax warnings arise during verification
	 of only the selected units and their direct dependencies.

Below are two service unit files that I created for the purposes of testing:

1. First, we run the commands on a unit that does not have dependencies but has a non-existing key-value setting (i.e. foo = bar).

> cat <<EOF>testcase.service

[Unit]
foo = bar

[Service]
ExecStart = echo hello
EOF

OUTPUT:

maanya-goenka@debian:~/systemd (log-error)$ sudo build/systemd-analyze verify testcase.service
/home/maanya-goenka/systemd/testcase.service:2: Unknown key name 'foo' in section 'Unit', ignoring.
/usr/lib/systemd/system/plymouth-start.service:15: Unit configured to use KillMode=none. This is unsafe, as it disables systemd's process lifecycle management for the service. Please update your service to use a safer KillMode=, such as 'mixed' or 'control-group'. Support for KillMode=none is deprecated and will eventually be removed.
/usr/lib/systemd/system/dbus.socket:5: ListenStream= references a path below legacy directory /var/run/, updating /var/run/dbus/system_bus_socket → /run/dbus/system_bus_socket; please update the unit file accordingly.
/usr/lib/systemd/system/gdm.service:30: Standard output type syslog is obsolete, automatically updating to journal. Please update your unit file, and consider removing the setting altogether.
maanya-goenka@debian:~/systemd (log-error)$ echo $?
1

maanya-goenka@debian:~/systemd (log-error)$ sudo build/systemd-analyze verify --recursive-errors=yes testcase.service
/home/maanya-goenka/systemd/testcase.service:2: Unknown key name 'foo' in section 'Unit', ignoring.
/usr/lib/systemd/system/plymouth-start.service:15: Unit configured to use KillMode=none. This is unsafe, as it disables systemd's process lifecycle management for the service. Please update your service to use a safer KillMode=, such as 'mixed' or 'control-group'. Support for KillMode=none is deprecated and will eventually be removed.
/usr/lib/systemd/system/dbus.socket:5: ListenStream= references a path below legacy directory /var/run/, updating /var/run/dbus/system_bus_socket → /run/dbus/system_bus_socket; please update the unit file accordingly.
/usr/lib/systemd/system/gdm.service:30: Standard output type syslog is obsolete, automatically updating to journal. Please update your unit file, and consider removing the setting altogether.
maanya-goenka@debian:~/systemd (log-error)$ echo $?
1

maanya-goenka@debian:~/systemd (log-error)$ sudo build/systemd-analyze verify --recursive-errors=no testcase.service
/home/maanya-goenka/systemd/testcase.service:2: Unknown key name 'foo' in section 'Unit', ignoring.
maanya-goenka@debian:~/systemd (log-error)$ echo $?
1

maanya-goenka@debian:~/systemd (log-error)$ sudo build/systemd-analyze verify --recursive-errors=one testcase.service
/home/maanya-goenka/systemd/testcase.service:2: Unknown key name 'foo' in section 'Unit', ignoring.
/usr/lib/systemd/system/plymouth-start.service:15: Unit configured to use KillMode=none. This is unsafe, as it disables systemd's process lifecycle management for the service. Please update your service to use a safer KillMode=, such as 'mixed' or 'control-group'. Support for KillMode=none is deprecated and will eventually be removed.
/usr/lib/systemd/system/dbus.socket:5: ListenStream= references a path below legacy directory /var/run/, updating /var/run/dbus/system_bus_socket → /run/dbus/system_bus_socket; please update the unit file accordingly.
/usr/lib/systemd/system/gdm.service:30: Standard output type syslog is obsolete, automatically updating to journal. Please update your unit file, and consider removing the setting altogether.
maanya-goenka@debian:~/systemd (log-error)$ echo $?
1

2. Next, we run the commands on a unit that is syntactically valid but has a non-existing dependency (i.e. foo2.service)

> cat <<EOF>foobar.service

[Unit]
Requires = foo2.service

[Service]
ExecStart = echo hello
EOF

OUTPUT:

maanya-goenka@debian:~/systemd (log-error)$ sudo build/systemd-analyze verify foobar.service
/usr/lib/systemd/system/plymouth-start.service:15: Unit configured to use KillMode=none. This is unsafe, as it disables systemd's process lifecycle management for the service. Please update your service to use a safer KillMode=, such as 'mixed' or 'control-group'. Support for KillMode=none is deprecated and will eventually be removed.
/usr/lib/systemd/system/dbus.socket:5: ListenStream= references a path below legacy directory /var/run/, updating /var/run/dbus/system_bus_socket → /run/dbus/system_bus_socket; please update the unit file accordingly.
/usr/lib/systemd/system/gdm.service:30: Standard output type syslog is obsolete, automatically updating to journal. Please update your unit file, and consider removing the setting altogether.
foobar.service: Failed to create foobar.service/start: Unit foo2.service not found.
maanya-goenka@debian:~/systemd (log-error)$ echo $?
1

maanya-goenka@debian:~/systemd (log-error)$ sudo build/systemd-analyze verify --recursive-errors=yes foobar.service
/usr/lib/systemd/system/plymouth-start.service:15: Unit configured to use KillMode=none. This is unsafe, as it disables systemd's process lifecycle management for the service. Please update your service to use a safer KillMode=, such as 'mixed' or 'control-group'. Support for KillMode=none is deprecated and will eventually be removed.
/usr/lib/systemd/system/dbus.socket:5: ListenStream= references a path below legacy directory /var/run/, updating /var/run/dbus/system_bus_socket → /run/dbus/system_bus_socket; please update the unit file accordingly.
/usr/lib/systemd/system/gdm.service:30: Standard output type syslog is obsolete, automatically updating to journal. Please update your unit file, and consider removing the setting altogether.
foobar.service: Failed to create foobar.service/start: Unit foo2.service not found.
maanya-goenka@debian:~/systemd (log-error)$ echo $?
1

maanya-goenka@debian:~/systemd (log-error)$ sudo build/systemd-analyze verify --recursive-errors=no foobar.service
maanya-goenka@debian:~/systemd (log-error)$ echo $?
0

maanya-goenka@debian:~/systemd (log-error)$ sudo build/systemd-analyze verify --recursive-errors=one foobar.service
/usr/lib/systemd/system/plymouth-start.service:15: Unit configured to use KillMode=none. This is unsafe, as it disables systemd's process lifecycle management for the service. Please update your service to use a safer KillMode=, such as 'mixed' or 'control-group'. Support for KillMode=none is deprecated and will eventually be removed.
/usr/lib/systemd/system/dbus.socket:5: ListenStream= references a path below legacy directory /var/run/, updating /var/run/dbus/system_bus_socket → /run/dbus/system_bus_socket; please update the unit file accordingly.
/usr/lib/systemd/system/gdm.service:30: Standard output type syslog is obsolete, automatically updating to journal. Please update your unit file, and consider removing the setting altogether.
foobar.service: Failed to create foobar.service/start: Unit foo2.service not found.
maanya-goenka@debian:~/systemd (log-error)$ echo $?
1

1 files changed, 63 insertions, 2 deletions

diff --git a/src/analyze/analyze-verify.c b/src/analyze/analyze-verify.c
index 9ef6868367..cd5377200b 100644
--- a/src/analyze/analyze-verify.c
+++ b/src/analyze/analyze-verify.c
@@ -11,10 +11,28 @@
 #include "manager.h"
 #include "pager.h"
 #include "path-util.h"
+#include "string-table.h"
 #include "strv.h"
 #include "unit-name.h"
 #include "unit-serialize.h"
 
+static void log_syntax_callback(const char *unit, int level, void *userdata) {
+        Set **s = userdata;
+        int r;
+
+        assert(userdata);
+        assert(unit);
+
+        if (level > LOG_WARNING)
+                return;
+
+        r = set_put_strdup(s, unit);
+        if (r < 0) {
+                set_free_free(*s);
+                *s = POINTER_MAX;
+        }
+}
+
 static int prepare_filename(const char *filename, char **ret) {
         int r;
         const char *name;
@@ -218,13 +236,22 @@ static int verify_unit(Unit *u, bool check_man, const char *root) {
         return r;
 }
 
-int verify_units(char **filenames, UnitFileScope scope, bool check_man, bool run_generators, const char *root) {
+static void set_destroy_ignore_pointer_max(Set** s) {
+        if (*s == POINTER_MAX)
+                return;
+        set_free_free(*s);
+}
+
+int verify_units(char **filenames, UnitFileScope scope, bool check_man, bool run_generators, RecursiveErrors recursive_errors, const char *root) {
         const ManagerTestRunFlags flags =
                 MANAGER_TEST_RUN_MINIMAL |
                 MANAGER_TEST_RUN_ENV_GENERATORS |
+                (recursive_errors == RECURSIVE_ERRORS_NO) * MANAGER_TEST_RUN_IGNORE_DEPENDENCIES |
                 run_generators * MANAGER_TEST_RUN_GENERATORS;
 
         _cleanup_(manager_freep) Manager *m = NULL;
+        _cleanup_(set_destroy_ignore_pointer_max) Set *s = NULL;
+        _unused_ _cleanup_(clear_log_syntax_callback) dummy_t dummy;
         Unit *units[strv_length(filenames)];
         _cleanup_free_ char *var = NULL;
         int r, k, i, count = 0;
@@ -233,6 +260,11 @@ int verify_units(char **filenames, UnitFileScope scope, bool check_man, bool run
         if (strv_isempty(filenames))
                 return 0;
 
+        /* Allow systemd-analyze to hook in a callback function so that it can get
+         * all the required log data from the function itself without having to rely
+         * on a global set variable for the same */
+        set_log_syntax_callback(log_syntax_callback, &s);
+
         /* set the path */
         r = generate_path(&var, filenames);
         if (r < 0)
@@ -283,5 +315,34 @@ int verify_units(char **filenames, UnitFileScope scope, bool check_man, bool run
                         r = k;
         }
 
-        return r;
+        if (s == POINTER_MAX)
+                return log_oom();
+
+        if (set_isempty(s) || r != 0)
+                return r;
+
+        /* If all previous verifications succeeded, then either the recursive parsing of all the
+         * associated dependencies with RECURSIVE_ERRORS_YES or the parsing of the specified unit file
+         * with RECURSIVE_ERRORS_NO must have yielded a syntax warning and hence, a non-empty set. */
+        if (IN_SET(recursive_errors, RECURSIVE_ERRORS_YES, RECURSIVE_ERRORS_NO))
+                return -ENOTRECOVERABLE;
+
+        /* If all previous verifications succeeded, then the non-empty set could have resulted from
+         * a syntax warning encountered during the recursive parsing of the specified unit file and
+         * its direct dependencies. Hence, search for any of the filenames in the set and if found,
+         * return a non-zero process exit status. */
+        if (recursive_errors == RECURSIVE_ERRORS_ONE)
+                STRV_FOREACH(filename, filenames)
+                        if (set_contains(s, basename(*filename)))
+                                return -ENOTRECOVERABLE;
+
+        return 0;
 }
+
+static const char* const recursive_errors_table[_RECURSIVE_ERRORS_MAX] = {
+        [RECURSIVE_ERRORS_NO]  = "no",
+        [RECURSIVE_ERRORS_YES] = "yes",
+        [RECURSIVE_ERRORS_ONE] = "one",
+};
+
+DEFINE_STRING_TABLE_LOOKUP(recursive_errors, RecursiveErrors);