support chrooting/setting of ioprio when spawning

execute.c

@@ -15,6 +15,7 @@
 #include "macro.h"
 #include "util.h"
 #include "log.h"
+#include "ioprio.h"
 
 static int close_fds(int except[], unsigned n_except) {
         DIR *d;
@@ -273,13 +274,13 @@ int exec_spawn(const ExecCommand *command, const ExecContext *context, int *fds,
                         goto fail;
                 }
 
-                umask(context->umask);
+                if (setpgid(0, 0) < 0) {
-
+                        r = EXIT_PGID;
-                if (chdir(context->directory ? context->directory : "/") < 0) {
-                        r = EXIT_CHDIR;
                         goto fail;
                 }
 
+                umask(context->umask);
+
                 if (setup_output(context, file_name_from_path(command->path)) < 0) {
                         r = EXIT_OUTPUT;
                         goto fail;
@@ -297,12 +298,29 @@ int exec_spawn(const ExecCommand *command, const ExecContext *context, int *fds,
                         }
                 }
 
+                if (context->root_directory)
+                        if (chroot(context->root_directory) < 0) {
+                                r = EXIT_CHROOT;
+                                goto fail;
+                        }
+
+                if (chdir(context->working_directory ? context->working_directory : "/") < 0) {
+                        r = EXIT_CHDIR;
+                        goto fail;
+                }
+
                 if (context->nice_set)
                         if (setpriority(PRIO_PROCESS, 0, context->nice) < 0) {
                                 r = EXIT_NICE;
                                 goto fail;
                         }
 
+                if (context->ioprio_set)
+                        if (ioprio_set(IOPRIO_WHO_PROCESS, 0, context->ioprio) < 0) {
+                                r = EXIT_IOPRIO;
+                                goto fail;
+                        }
+
                 if (close_fds(fds, n_fds) < 0 ||
                     shift_fds(fds, n_fds) < 0 ||
                     flags_fds(fds, n_fds) < 0) {
@@ -366,8 +384,13 @@ void exec_context_init(ExecContext *c) {
 
         c->umask = 0002;
         cap_clear(c->capabilities);
+        c->capabilities_set = false;
         c->oom_adjust = 0;
+        c->oom_adjust_set = false;
         c->nice = 0;
+        c->nice_set = false;
+        c->ioprio = IOPRIO_PRIO_VALUE(IOPRIO_CLASS_BE, 0);
+        c->ioprio_set = false;
 
         c->output = 0;
         c->syslog_priority = LOG_DAEMON|LOG_INFO;
@@ -386,8 +409,10 @@ void exec_context_done(ExecContext *c) {
                 c->rlimit[l] = NULL;
         }
 
-        free(c->directory);
+        free(c->working_directory);
-        c->directory = NULL;
+        c->working_directory = NULL;
+        free(c->root_directory);
+        c->root_directory = NULL;
 
         free(c->syslog_identifier);
         c->syslog_identifier = NULL;
@@ -424,6 +449,14 @@ void exec_command_free_array(ExecCommand **c, unsigned n) {
 }
 
 void exec_context_dump(ExecContext *c, FILE* f, const char *prefix) {
+
+        static const char * const table[] = {
+                [IOPRIO_CLASS_NONE] = "none",
+                [IOPRIO_CLASS_RT] = "realtime",
+                [IOPRIO_CLASS_BE] = "best-effort",
+                [IOPRIO_CLASS_IDLE] = "idle"
+        };
+
         assert(c);
         assert(f);
 
@@ -432,9 +465,11 @@ void exec_context_dump(ExecContext *c, FILE* f, const char *prefix) {
 
         fprintf(f,
                 "%sUmask: %04o\n"
-                "%sDirectory: %s\n",
+                "%sWorking Directory: %s\n"
+                "%sRoot Directory: %s\n",
                 prefix, c->umask,
-                prefix, c->directory ? c->directory : "/");
+                prefix, c->working_directory ? c->working_directory : "/",
+                prefix, c->root_directory ? c->root_directory : "/");
 
         if (c->nice_set)
                 fprintf(f,
@@ -445,6 +480,13 @@ void exec_context_dump(ExecContext *c, FILE* f, const char *prefix) {
                 fprintf(f,
                         "%sOOMAdjust: %i\n",
                         prefix, c->oom_adjust);
+
+        if (c->ioprio_set)
+                fprintf(f,
+                        "%sIOSchedulingClass: %s\n"
+                        "%sIOPriority: %i\n",
+                        prefix, table[IOPRIO_PRIO_CLASS(c->ioprio)],
+                        prefix, (int) IOPRIO_PRIO_DATA(c->ioprio));
 }
 
 void exec_status_fill(ExecStatus *s, pid_t pid, int code, int status) {

execute.h

@@ -44,12 +44,14 @@ struct ExecContext {
         char **environment;
         mode_t umask;
         struct rlimit *rlimit[RLIMIT_NLIMITS];  /* FIXME: load-fragment parser missing */
-        char *directory;
+        char *working_directory, *root_directory;
         int oom_adjust;
         int nice;
+        int ioprio;
 
         bool oom_adjust_set:1;
         bool nice_set:1;
+        bool ioprio_set:1;
 
         ExecOutput output;
         int syslog_priority;
@@ -91,7 +93,10 @@ typedef enum ExitStatus {
         EXIT_LIMITS,
         EXIT_OOM_ADJUST,
         EXIT_SIGNAL_MASK,
-        EXIT_OUTPUT
+        EXIT_OUTPUT,
+        EXIT_CHROOT,
+        EXIT_PGID,
+        EXIT_IOPRIO
 } ExitStatus;
 
 int exec_spawn(const ExecCommand *command, const ExecContext *context, int *fds, unsigned n_fds, pid_t *ret);

fixme

@@ -27,9 +27,9 @@
 
 - implement mount/automount
 
-- more process attributes: chroot, cpu affinity, scheduling
+- more process attributes: cpu affinity, cpu scheduling
 
-- create session/pgroup for child processes
+- create session/pgroup for child processes? handle input on console properly? interactive fsck? interactive luks password?
 
 - fs namespaces
 
@@ -45,3 +45,10 @@
   presumably uses the logging socket in blocking mode which might
   trigger a deadlock if syslog does not process the socket anymore
   (maybe because it is restarted) and the socket buffer is full.
+
+- in udev/mount if properties change we need to delete the old
+  settings and install the new settings. Deleting the old settings is
+  currently missing.
+
+- ability to kill services? i.e. in contrast to stopping them, go directly
+  into killing mode?

load-fragment.c

@@ -12,6 +12,7 @@
 #include "conf-parser.h"
 #include "load-fragment.h"
 #include "log.h"
+#include "ioprio.h"
 
 static int config_parse_deps(
                 const char *filename,
@@ -625,6 +626,90 @@ int config_parse_level(
         return 0;
 }
 
+int config_parse_io_class(
+                const char *filename,
+                unsigned line,
+                const char *section,
+                const char *lvalue,
+                const char *rvalue,
+                void *data,
+                void *userdata) {
+
+        static const char * const table[] = {
+                [IOPRIO_CLASS_NONE] = NULL,
+                [IOPRIO_CLASS_RT] = "realtime",
+                [IOPRIO_CLASS_BE] = "best-effort",
+                [IOPRIO_CLASS_IDLE] = "idle",
+        };
+
+        ExecContext *c = data;
+        int i;
+
+        assert(filename);
+        assert(lvalue);
+        assert(rvalue);
+        assert(data);
+
+        for (i = 0; i < (int) ELEMENTSOF(table); i++) {
+                if (!table[i])
+                        continue;
+
+                if (streq(rvalue, table[i])) {
+                        c->ioprio = IOPRIO_PRIO_VALUE(i, IOPRIO_PRIO_DATA(c->ioprio));
+                        break;
+                }
+        }
+
+        if (i >= (int) ELEMENTSOF(table)) {
+
+                /* Second try, let's see if this is a number. */
+                if (safe_atoi(rvalue, &i) >= 0 &&
+                    i >= 0 &&
+                    i < (int) ELEMENTSOF(table) &&
+                    table[i])
+                        c->ioprio = IOPRIO_PRIO_VALUE(i, IOPRIO_PRIO_DATA(c->ioprio));
+                else {
+                        log_error("[%s:%u] Failed to parse io priority: %s", filename, line, rvalue);
+                        return -EBADMSG;
+                }
+        }
+
+        c->ioprio_set = true;
+
+        return 0;
+}
+
+int config_parse_io_priority(
+                const char *filename,
+                unsigned line,
+                const char *section,
+                const char *lvalue,
+                const char *rvalue,
+                void *data,
+                void *userdata) {
+
+        ExecContext *c = data;
+        int i;
+
+        assert(filename);
+        assert(lvalue);
+        assert(rvalue);
+        assert(data);
+
+        if (safe_atoi(rvalue, &i) >= 0 &&
+            i >= 0 &&
+            i < IOPRIO_BE_NR)
+                c->ioprio = IOPRIO_PRIO_VALUE(IOPRIO_PRIO_CLASS(c->ioprio), i);
+        else {
+                log_error("[%s:%u] Failed to parse io priority: %s", filename, line, rvalue);
+                return -EBADMSG;
+        }
+
+        c->ioprio_set = true;
+
+        return 0;
+}
+
 #define FOLLOW_MAX 8
 
 static int open_follow(char **filename, FILE **_f, Set *names, char **_id) {
@@ -709,12 +794,15 @@ static int load_from_path(Unit *u, const char *path) {
         };
 
 #define EXEC_CONTEXT_CONFIG_ITEMS(context, section) \
-                { "Directory",              config_parse_path,            &(context).directory,                            section   }, \
+                { "WorkingDirectory",       config_parse_path,            &(context).working_directory,                    section   }, \
+                { "RootDirectory",          config_parse_path,            &(context).root_directory,                       section   }, \
                 { "User",                   config_parse_string,          &(context).user,                                 section   }, \
                 { "Group",                  config_parse_string,          &(context).group,                                section   }, \
                 { "SupplementaryGroups",    config_parse_strv,            &(context).supplementary_groups,                 section   }, \
                 { "Nice",                   config_parse_nice,            &(context),                                      section   }, \
                 { "OOMAdjust",              config_parse_oom_adjust,      &(context),                                      section   }, \
+                { "IOPriority",             config_parse_io_priority,     &(context),                                      section   }, \
+                { "IOSchedulingClass",      config_parse_io_class,        &(context),                                      section   }, \
                 { "UMask",                  config_parse_umask,           &(context).umask,                                section   }, \
                 { "Environment",            config_parse_strv,            &(context).environment,                          section   }, \
                 { "Output",                 config_parse_output,          &(context).output,                               section   }, \