add support for passing arguments to services

doc/manpages/dinit-service.5.m4

@@ -12,15 +12,22 @@ Dinit service description files
 .SH DESCRIPTION
 .\"
 The service description files for \fBDinit\fR each describe a service. The name
-of the file corresponds to the name of the service it describes. 
+of the file corresponds to the name of the service it describes, minus its argument.
 .LP
 Service description files specify the various attributes of a service. A
-service description file is named after the service it represents, and is
-a plain-text file with simple key-value format.
+service description file is named after the service it represents (without
+its argument), and is a plain-text file with simple key-value format.
 The description files are located in a service description directory;
 See \fBdinit\fR(8) for more details of the default service description directories,
 and how and when service descriptions are loaded.
 .LP
+The full name of the service includes its argument, such as \fIservice@argument\fR.
+The argument is optional, so you can also invoke just \fIservice\fR. Each instance
+of a service, i.e. with different arguments, is separate, including loading. This
+means every time you invoke the service with a different argument, it is loaded
+separately. Empty argument is not the same as missing argument, as this affects
+variable substitution (see \fBVARIABLE SUBSTITUTION\fR).
+.LP
 All services have a \fItype\fR and a set of \fIdependencies\fR. These are discussed
 in the following subsections. The type, dependencies, and other attributes are
 specified via property settings, the format of which are documented in the
@@ -269,6 +276,8 @@ This service depends on the named service.
 Starting this service will start the named service; the command to start this service will not be executed
 until the named service has started.
 If the named service stops then this service will also be stopped.
+The \fIservice-name\fR is subject to minimal variable substitution
+(see \fBVARIABLE SUBSTITUTION\fR).
 .TP
 \fBdepends\-ms\fR: \fIservice-name\fR
 This service has a "milestone" dependency on the named service. Starting this
@@ -277,13 +286,15 @@ named service has started, and will fail to start if the named service does
 not start.
 Once the named (dependent) service reaches the started state, however, the
 dependency may stop without affecting the dependent service.
+The name is likewise subject to minimal variable substitution.
 .TP
 \fBwaits\-for\fR: \fIservice-name\fR
 When this service is started, wait for the named service to finish starting
 (or to fail starting) before commencing the start procedure for this service.
 Starting this service will automatically start the named service.
 If the named service fails to start, this service will start as usual (subject to
 other dependencies being met).
+The name is likewise subject to minimal variable substitution.
 .TP
 \fBdepends\-on.d\fR: \fIdirectory-path\fR
 For each file name in \fIdirectory-path\fR which does not begin with a dot,
@@ -296,6 +307,7 @@ is not considered fatal.
 .IP
 The directory path, if not absolute, is relative to the directory containing the service
 description file.
+No variable substitution is done for path dependencies.
 .TP
 \fBdepends\-ms.d\fR: \fIdirectory-path\fR
 As for \fBdepends-on.d\fR, but with dependency type \fBdepends\-ms\fR.
@@ -311,13 +323,17 @@ starting this service will not cause it to start (nor wait for it in that case).
 It does not by itself cause the named service to be loaded (if loaded later, the "after"
 relationship will be enforced from that point).
 .TP
+The name is subject to minimal variable substitution.
+.TP
 \fBbefore\fR: \fIservice-name\fR
 When starting the named service, if this service is also starting, wait for this service
 to finish starting before bringing the named service up. This is largely equivalent to specifying
 an \fBafter\fR relationship to this service from the named service.
 However, it does not by itself cause the named service to be loaded (if loaded later, the "before"
 relationship will be enforced from that point).
 .TP
+The name is subject to minimal variable substitution.
+.TP
 \fBchain\-to\fR = \fIservice-name\fR
 When this service terminates (i.e. starts successfully, and then stops of its
 own accord), the named service should be started.
@@ -338,6 +354,8 @@ stopped due to a dependency stopping (for any reason), if it will restart
 abnormally or with an exit status indicating an error.
 However, if the \fBalways-chain\fR option is set the chain is started regardless of the
 reason and the status of this service termination.
+.IP
+The name is subject to minimal variable substitution.
 .TP
 \fBsocket\-listen\fR = \fIsocket-path\fR
 Pre-open a socket for the service and pass it to the service using the
@@ -711,6 +729,10 @@ set and non\-empty), and `\fB${NAME+word}\fR' (substitute `\fBword\fR' if variab
 Unlike in shell expansion, the substituted \fBword\fR does not itself undergo expansion and
 cannot contain closing brace characters or whitespace, even if quoted.
 .LP
+To substitute the service argument, the `\fB$1\fR' syntax may be used. The complete syntax
+of the substitution is supported here. Services without an argument are treated as if the
+variable was unset, which affects some of the curly brace syntax variants.
+.LP
 Note that by default, command-line variable substitution occurs after splitting the line into
 separate arguments and so
 a single environment variable cannot be used to add multiple arguments to a command line.
@@ -741,6 +763,10 @@ used for substitution, if they have been changed in the meantime.
 Using environment variable values in service commands and parameters can be used as means to
 provide easily-adjustable service configuration, but is not ideal for this purpose and alternatives
 should be considered. 
+.LP
+In dependency fields, including \fIbefore\fR and similar, minimal version of variable
+substitution may happen. Only the service argument may be substituted. No curly brace
+syntax is supported. Escaping to avoid substitution is still supported.
 .\"
 .SS META-COMMANDS
 .\"

doc/manpages/dinit.8.m4

@@ -119,7 +119,7 @@ Specifies the name of a service that should be started (along with its
 dependencies).
 If none are specified, defaults to \fIboot\fR (which requires that a suitable service description
 for the \fIboot\fR service exists). Multiple services can be specified in which case they will each
-be started.
+be started. An argument to the service may be included here.
 .sp
 \fBNote:\fR on Linux, if \fBdinit\fR is running as PID 1 and with UID 0, it may ignore "naked"
 service names (without preceding \fB\-\-service\fR/\fB\-t\fR) provided on the command line.

doc/manpages/dinitctl.8.m4

@@ -162,7 +162,8 @@ success.
 Clear the log buffer for the service after displaying it.
 .TP
 \fIservice-name\fR
-Specifies the name of the service to which the command applies.
+Specifies the name of the service to which the command applies. It may have an argument that is passed
+to the service.
 .\"
 .SH COMMAND DESCRIPTIONS
 .\"

src/dinitcheck.cc

@@ -671,7 +671,7 @@ service_record *load_service(service_set_t &services, const std::string &name,
             };
 
             try {
-                process_service_line(settings, name.c_str(), line, input_pos, setting, op, i, end,
+                process_service_line(settings, name.c_str(), nullptr, line, input_pos, setting, op, i, end,
                         load_service_n, process_dep_dir_n);
             }
             catch (service_description_exc &exc) {
@@ -745,7 +745,7 @@ service_record *load_service(service_set_t &services, const std::string &name,
         return resolve_env_var(name, envmap);
     };
 
-    settings.finalise(report_err, renvmap, report_err, resolve_var);
+    settings.finalise(report_err, renvmap, nullptr, report_err, resolve_var);
 
     if (!settings.working_dir.empty()) {
         service_wdir = settings.working_dir;

src/igr-tests/igr-runner.cc

@@ -40,6 +40,7 @@ void catlog_test();
 void offline_enable_test();
 void xdg_config_test();
 void cycles_test();
+void svc_arg_test();
 
 int main(int argc, char **argv)
 {
@@ -55,7 +56,8 @@ int main(int argc, char **argv)
             { "pseudo-cycle", pseudo_cycle_test }, { "before-after", before_after_test},
             { "before-after2", before_after2_test }, { "log-via-pipe", log_via_pipe_test },
             { "catlog", catlog_test }, { "offline-enable", offline_enable_test },
-            { "xdg-config", xdg_config_test }, { "cycles", cycles_test } };
+            { "xdg-config", xdg_config_test }, { "cycles", cycles_test },
+            { "svc-arg", svc_arg_test } };
     constexpr int num_tests = sizeof(tests) / sizeof(tests[0]);
 
     dinit_bindir = "../..";
@@ -974,3 +976,23 @@ void cycles_test()
     igr_assert_eq(read_file_contents(igr_input_basedir + "/cycles/expected-after_self"),
             dinitctl_p.get_stderr());
 }
+
+void svc_arg_test()
+{
+    igr_test_setup setup("svc-arg");
+    std::string output_file = setup.prep_output_file("svc-arg-record");
+    std::string socket_path = setup.prep_socket_path();
+
+    igr_env_var_setup env_output("OUTPUT", output_file.c_str());
+
+    dinit_proc dinit_p;
+    dinit_p.start("svc-arg", {"-u", "-d", "sd", "-p", socket_path, "-q", "checkarg@foo"});
+    dinit_p.wait_for_term({1,0} /* max 1 second */);
+
+    check_file_contents(output_file, std::string() +
+            "test-$1\n" +
+            "test-hello\n" +
+            "hello\n" +
+            "foo\n" +
+            "foo\n");
+}

src/igr-tests/svc-arg/checkarg.sh

@@ -0,0 +1,3 @@
+#!/bin/sh
+
+echo "$1" >> "$OUTPUT"

src/igr-tests/svc-arg/sd/checkarg

@@ -0,0 +1,4 @@
+type = process
+waits-for = checkarg2@$1
+command = ../checkarg.sh $1
+restart = false

src/igr-tests/svc-arg/sd/checkarg2

@@ -0,0 +1,3 @@
+type = scripted
+waits-for = checkarg3@hello
+command = ../checkarg.sh $1

src/igr-tests/svc-arg/sd/checkarg3

@@ -0,0 +1,3 @@
+type = scripted
+waits-for = checkarg4@test-$1
+command = ../checkarg.sh $1

src/igr-tests/svc-arg/sd/checkarg4

@@ -0,0 +1,3 @@
+type = scripted
+waits-for = checkarg5@test-$$1
+command = ../checkarg.sh $1

src/igr-tests/svc-arg/sd/checkarg5

@@ -0,0 +1,2 @@
+type = scripted
+command = ../checkarg.sh $1

src/includes/load-service.h

@@ -547,6 +547,27 @@ inline string read_setting_value(file_pos_ref input_pos, string_iterator &i, str
     return rval;
 }
 
+// Reads a dependency name while performing minimal argument expansion in it.
+inline string read_dependency_value(file_pos_ref input_pos, string_iterator &i, string_iterator end,
+        const char *argval)
+{
+    string rval;
+    if (!argval) argval = "";
+    read_setting_value(rval, setting_op_t::ASSIGN, input_pos, i, end, nullptr);
+    for (auto v = rval.find('$'); v != rval.npos && v != (rval.size() - 1); v = rval.find('$', v + 1)) {
+        switch (rval[v + 1]) {
+        case '$':
+            rval.erase(v, 1);
+            break;
+        case '1':
+            rval.replace(v, 2, argval);
+            v += strlen(argval) - 1;
+            continue;
+        }
+    }
+    return rval;
+}
+
 inline void fill_environment_userinfo(uid_t uid, const std::string &service_name, environment &env)
 {
     if (uid == (uid_t)-1) {
@@ -1031,7 +1052,7 @@ inline const char *resolve_env_var(const string &name, const environment::env_ma
 template <typename T>
 static void value_var_subst(const char *setting_name, std::string &line,
         std::list<std::pair<unsigned,unsigned>> &offsets, T &var_resolve,
-        environment::env_map const &envmap)
+        environment::env_map const &envmap, const char *argval = nullptr)
 {
     auto dindx = line.find('$');
     if (dindx == string::npos) {
@@ -1074,11 +1095,16 @@ static void value_var_subst(const char *setting_name, std::string &line,
                 bool brace = line[spos] == '{';
                 if (brace) ++spos;
                 auto j = std::next(line.begin(), spos);
+                // may be a service argument
+                bool is_arg = j != token_end && *j == '1';
                 // read environment variable name
-                string name = read_config_name(j, token_end, true);
-                if (name.empty()) {
-                    throw service_description_exc(setting_name, "invalid/missing variable name after '$'");
-                }
+                string name;
+                if (!is_arg) {
+                    name = read_config_name(j, token_end, true);
+                    if (name.empty()) {
+                        throw service_description_exc(setting_name, "invalid/missing variable name after '$'");
+                    }
+                } else ++j;
                 char altmode = '\0';
                 bool colon = false;
                 auto altbeg = j, altend = j;
@@ -1106,7 +1132,7 @@ static void value_var_subst(const char *setting_name, std::string &line,
                 }
                 size_t line_len_before = r_line.size();
                 string_view resolved_vw;
-                auto *resolved = var_resolve(name, envmap);
+                auto *resolved = is_arg ? argval : var_resolve(name, envmap);
                 if (resolved) {
                     resolved_vw = resolved;
                 }
@@ -1300,7 +1326,7 @@ class service_settings_wrapper
     //     var_subst - functor to resolve environment variable values
     template <bool propagate_sde = false, typename T, typename U = decltype(dummy_lint), typename V = decltype(resolve_env_var),
             bool do_report_lint = !std::is_same<U, decltype(dummy_lint)>::value>
-    void finalise(T &report_error, environment::env_map const &envmap, U &report_lint = dummy_lint, V &var_subst = resolve_env_var)
+    void finalise(T &report_error, environment::env_map const &envmap, const char *argval, U &report_lint = dummy_lint, V &var_subst = resolve_env_var)
     {
         if (service_type == service_type_t::PROCESS || service_type == service_type_t::BGPROCESS
                 || service_type == service_type_t::SCRIPTED) {
@@ -1384,7 +1410,7 @@ class service_settings_wrapper
                 try {
                     offsets.front().first = 0;
                     offsets.front().second = setting_value.size();
-                    value_var_subst(setting_name, setting_value, offsets, var_subst, envmap);
+                    value_var_subst(setting_name, setting_value, offsets, var_subst, envmap, argval);
                 }
                 catch (service_description_exc &exc) {
                     if (propagate_sde) throw;
@@ -1460,7 +1486,7 @@ class service_settings_wrapper
 template <typename settings_wrapper,
     typename load_service_t,
     typename process_dep_dir_t>
-void process_service_line(settings_wrapper &settings, const char *name, string &line,
+void process_service_line(settings_wrapper &settings, const char *name, const char *arg, string &line,
         file_pos_ref input_pos, string &setting, setting_op_t setting_op, string::iterator &i,
         string::iterator &end, load_service_t load_service,
         process_dep_dir_t process_dep_dir)
@@ -1524,20 +1550,21 @@ void process_service_line(settings_wrapper &settings, const char *name, string &
             break;
         case setting_id_t::DEPENDS_ON:
         {
-            string dependency_name = read_setting_value(input_pos, i, end);
-            settings.depends.emplace_back(load_service(dependency_name.c_str()), dependency_type::REGULAR);
+            string dependency_name = read_dependency_value(input_pos, i, end, arg);
+            settings.depends.emplace_back(load_service(dependency_name.c_str()),
+                    dependency_type::REGULAR);
             break;
         }
         case setting_id_t::DEPENDS_MS:
         {
-            string dependency_name = read_setting_value(input_pos, i, end);
+            string dependency_name = read_dependency_value(input_pos, i, end, arg);
             settings.depends.emplace_back(load_service(dependency_name.c_str()),
                     dependency_type::MILESTONE);
             break;
         }
         case setting_id_t::WAITS_FOR:
         {
-            string dependency_name = read_setting_value(input_pos, i, end);
+            string dependency_name = read_dependency_value(input_pos, i, end, arg);
             settings.depends.emplace_back(load_service(dependency_name.c_str()),
                     dependency_type::WAITS_FOR);
             break;
@@ -1556,20 +1583,19 @@ void process_service_line(settings_wrapper &settings, const char *name, string &
         }
         case setting_id_t::DEPENDS_MS_D:
         {
-            string dependency_name = read_setting_value(input_pos, i, end);
-            settings.depends.emplace_back(load_service(dependency_name.c_str()),
-                    dependency_type::MILESTONE);
+            string depends_ms_d = read_setting_value(input_pos, i, end);
+            process_dep_dir(settings.depends, depends_ms_d, dependency_type::MILESTONE);
             break;
         }
         case setting_id_t::AFTER:
         {
-            string after_name = read_setting_value(input_pos, i, end);
+            string after_name = read_dependency_value(input_pos, i, end, arg);
             settings.after_svcs.emplace_back(std::move(after_name));
             break;
         }
         case setting_id_t::BEFORE:
         {
-            string before_name = read_setting_value(input_pos, i, end);
+            string before_name = read_dependency_value(input_pos, i, end, arg);
             settings.before_svcs.emplace_back(std::move(before_name));
             break;
         }