core: accept time units for time-based resource limits

Let's make sure "LimitCPU=30min" can be parsed properly, following the
usual logic how we parse time values. Similar for LimitRTTIME=.

While we are at it, extend a bit on the man page section about resource
limits.

Fixes: #1772

5 files changed, 231 insertions, 23 deletions

diff --git a/man/systemd.exec.xml b/man/systemd.exec.xml
index 96298f11ed..2b090871ff 100644
--- a/man/systemd.exec.xml
+++ b/man/systemd.exec.xml
@@ -568,90 +568,133 @@
         of various resources for executed processes. See
         <citerefentry><refentrytitle>setrlimit</refentrytitle><manvolnum>2</manvolnum></citerefentry>
         for details. Use the string <varname>infinity</varname> to
-        configure no limit on a specific resource. The multiplicative suffixes
-        K (=1024), M (=1024*1024) and so on for G, T, P and E may be used for
-        resource limits measured in bytes (e.g. LimitAS=16G).</para></listitem>
+        configure no limit on a specific resource. The multiplicative
+        suffixes K (=1024), M (=1024*1024) and so on for G, T, P and E
+        may be used for resource limits measured in bytes
+        (e.g. LimitAS=16G). For the limits referring to time values,
+        the usual time units ms, s, min, h and so on may be used (see
+        <citerefentry><refentrytitle>systemd.time</refentrytitle><manvolnum>7</manvolnum></citerefentry>
+        for details). Note that if no time unit is specified for
+        <varname>LimitCPU=</varname> the default unit of seconds is
+        implied, while for <varname>LimitRTTIME=</varname> the default
+        unit of microseconds is implied. Also, note that the effective
+        granularity of the limits might influence their
+        enforcement. For example, time limits specified for
+        <varname>LimitCPU=</varname> will be rounded up implicitly to
+        multiples of 1s.</para>
+
+        <para>Note that most process resource limits configured with
+        these options are per-process, and processes may fork in order
+        to acquire a new set of resources that are accounted
+        independently of the original process, and may thus escape
+        limits set. Also note that <varname>LimitRSS=</varname> is not
+        implemented on Linux, and setting it has no effect. Often it
+        is advisable to prefer the resource controls listed in
+        <citerefentry><refentrytitle>systemd.resource-control</refentrytitle><manvolnum>5</manvolnum></citerefentry>
+        over these per-process limits, as they apply to services as a
+        whole, may be altered dynamically at runtime, and are
+        generally more expressive. For example,
+        <varname>MemoryLimit=</varname> is a more powerful (and
+        working) replacement for <varname>LimitRSS=</varname>.</para>
 
         <table>
           <title>Limit directives and their equivalent with ulimit</title>
 
-          <tgroup cols='2'>
+          <tgroup cols='3'>
             <colspec colname='directive' />
             <colspec colname='equivalent' />
+            <colspec colname='unit' />
             <thead>
               <row>
                 <entry>Directive</entry>
                 <entry>ulimit equivalent</entry>
+                <entry>Unit</entry>
               </row>
             </thead>
             <tbody>
               <row>
-                <entry>LimitCPU</entry>
+                <entry>LimitCPU=</entry>
                 <entry>ulimit -t</entry>
+                <entry>Seconds</entry>
               </row>
               <row>
-                <entry>LimitFSIZE</entry>
+                <entry>LimitFSIZE=</entry>
                 <entry>ulimit -f</entry>
+                <entry>Bytes</entry>
               </row>
               <row>
-                <entry>LimitDATA</entry>
+                <entry>LimitDATA=</entry>
                 <entry>ulimit -d</entry>
+                <entry>Bytes</entry>
               </row>
               <row>
-                <entry>LimitSTACK</entry>
+                <entry>LimitSTACK=</entry>
                 <entry>ulimit -s</entry>
+                <entry>Bytes</entry>
               </row>
               <row>
-                <entry>LimitCORE</entry>
+                <entry>LimitCORE=</entry>
                 <entry>ulimit -c</entry>
+                <entry>Bytes</entry>
               </row>
               <row>
-                <entry>LimitRSS</entry>
+                <entry>LimitRSS=</entry>
                 <entry>ulimit -m</entry>
+                <entry>Bytes</entry>
               </row>
               <row>
-                <entry>LimitNOFILE</entry>
+                <entry>LimitNOFILE=</entry>
                 <entry>ulimit -n</entry>
+                <entry>Number of File Descriptors</entry>
               </row>
               <row>
-                <entry>LimitAS</entry>
+                <entry>LimitAS=</entry>
                 <entry>ulimit -v</entry>
+                <entry>Bytes</entry>
               </row>
               <row>
-                <entry>LimitNPROC</entry>
+                <entry>LimitNPROC=</entry>
                 <entry>ulimit -u</entry>
+                <entry>Number of Processes</entry>
               </row>
               <row>
-                <entry>LimitMEMLOCK</entry>
+                <entry>LimitMEMLOCK=</entry>
                 <entry>ulimit -l</entry>
+                <entry>Bytes</entry>
               </row>
               <row>
-                <entry>LimitLOCKS</entry>
+                <entry>LimitLOCKS=</entry>
                 <entry>ulimit -x</entry>
+                <entry>Number of Locks</entry>
               </row>
               <row>
-                <entry>LimitSIGPENDING</entry>
+                <entry>LimitSIGPENDING=</entry>
                 <entry>ulimit -i</entry>
+                <entry>Number of Queued Signals</entry>
               </row>
               <row>
-                <entry>LimitMSGQUEUE</entry>
+                <entry>LimitMSGQUEUE=</entry>
                 <entry>ulimit -q</entry>
+                <entry>Bytes</entry>
               </row>
               <row>
-                <entry>LimitNICE</entry>
+                <entry>LimitNICE=</entry>
                 <entry>ulimit -e</entry>
+                <entry>Nice Level</entry>
               </row>
               <row>
-                <entry>LimitRTPRIO</entry>
+                <entry>LimitRTPRIO=</entry>
                 <entry>ulimit -r</entry>
+                <entry>Realtime Priority</entry>
               </row>
               <row>
-                <entry>LimitRTTIME</entry>
+                <entry>LimitRTTIME=</entry>
                 <entry>No equivalent</entry>
+                <entry>Microseconds</entry>
               </row>
             </tbody>
           </tgroup>
-        </table>
+        </table></listitem>
       </varlistentry>
 
       <varlistentry>
@@ -1320,6 +1363,7 @@
         <citerefentry><refentrytitle>systemd.mount</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
         <citerefentry><refentrytitle>systemd.kill</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
         <citerefentry><refentrytitle>systemd.resource-control</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
+        <citerefentry><refentrytitle>systemd.time</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
         <citerefentry><refentrytitle>systemd.directives</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
         <citerefentry><refentrytitle>tmpfiles.d</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
         <citerefentry project='man-pages'><refentrytitle>exec</refentrytitle><manvolnum>3</manvolnum></citerefentry>
diff --git a/src/core/load-fragment-gperf.gperf.m4 b/src/core/load-fragment-gperf.gperf.m4
index 5b7954dbf9..75388659e3 100644
--- a/src/core/load-fragment-gperf.gperf.m4
+++ b/src/core/load-fragment-gperf.gperf.m4
@@ -58,7 +58,7 @@ $1.RestrictAddressFamilies,      config_parse_address_families,      0,
 $1.SystemCallArchitectures,      config_parse_warn_compat,           DISABLED_CONFIGURATION,        0
 $1.SystemCallErrorNumber,        config_parse_warn_compat,           DISABLED_CONFIGURATION,        0
 $1.RestrictAddressFamilies,      config_parse_warn_compat,           DISABLED_CONFIGURATION,        0')
-$1.LimitCPU,                     config_parse_limit,                 RLIMIT_CPU,                    offsetof($1, exec_context.rlimit)
+$1.LimitCPU,                     config_parse_sec_limit,             RLIMIT_CPU,                    offsetof($1, exec_context.rlimit)
 $1.LimitFSIZE,                   config_parse_bytes_limit,           RLIMIT_FSIZE,                  offsetof($1, exec_context.rlimit)
 $1.LimitDATA,                    config_parse_bytes_limit,           RLIMIT_DATA,                   offsetof($1, exec_context.rlimit)
 $1.LimitSTACK,                   config_parse_bytes_limit,           RLIMIT_STACK,                  offsetof($1, exec_context.rlimit)
@@ -73,7 +73,7 @@ $1.LimitSIGPENDING,              config_parse_limit,                 RLIMIT_SIGP
 $1.LimitMSGQUEUE,                config_parse_bytes_limit,           RLIMIT_MSGQUEUE,               offsetof($1, exec_context.rlimit)
 $1.LimitNICE,                    config_parse_limit,                 RLIMIT_NICE,                   offsetof($1, exec_context.rlimit)
 $1.LimitRTPRIO,                  config_parse_limit,                 RLIMIT_RTPRIO,                 offsetof($1, exec_context.rlimit)
-$1.LimitRTTIME,                  config_parse_limit,                 RLIMIT_RTTIME,                 offsetof($1, exec_context.rlimit)
+$1.LimitRTTIME,                  config_parse_usec_limit,            RLIMIT_RTTIME,                 offsetof($1, exec_context.rlimit)
 $1.ReadWriteDirectories,         config_parse_namespace_path_strv,   0,                             offsetof($1, exec_context.read_write_dirs)
 $1.ReadOnlyDirectories,          config_parse_namespace_path_strv,   0,                             offsetof($1, exec_context.read_only_dirs)
 $1.InaccessibleDirectories,      config_parse_namespace_path_strv,   0,                             offsetof($1, exec_context.inaccessible_dirs)
diff --git a/src/core/load-fragment.c b/src/core/load-fragment.c
index cdc2ad950d..28b90eccc1 100644
--- a/src/core/load-fragment.c
+++ b/src/core/load-fragment.c
@@ -1136,6 +1136,107 @@ int config_parse_bytes_limit(
         return 0;
 }
 
+int config_parse_sec_limit(
+                const char *unit,
+                const char *filename,
+                unsigned line,
+                const char *section,
+                unsigned section_line,
+                const char *lvalue,
+                int ltype,
+                const char *rvalue,
+                void *data,
+                void *userdata) {
+
+        struct rlimit **rl = data;
+        rlim_t seconds;
+        int r;
+
+        assert(filename);
+        assert(lvalue);
+        assert(rvalue);
+        assert(data);
+
+        rl += ltype;
+
+        if (streq(rvalue, "infinity"))
+                seconds = RLIM_INFINITY;
+        else {
+                usec_t t;
+
+                r = parse_sec(rvalue, &t);
+                if (r < 0) {
+                        log_syntax(unit, LOG_ERR, filename, line, r, "Failed to parse resource value, ignoring: %s", rvalue);
+                        return 0;
+                }
+
+                if (t == USEC_INFINITY)
+                        seconds = RLIM_INFINITY;
+                else
+                        seconds = (rlim_t) (DIV_ROUND_UP(t, USEC_PER_SEC));
+        }
+
+        if (!*rl) {
+                *rl = new(struct rlimit, 1);
+                if (!*rl)
+                        return log_oom();
+        }
+
+        (*rl)->rlim_cur = (*rl)->rlim_max = seconds;
+        return 0;
+}
+
+
+int config_parse_usec_limit(
+                const char *unit,
+                const char *filename,
+                unsigned line,
+                const char *section,
+                unsigned section_line,
+                const char *lvalue,
+                int ltype,
+                const char *rvalue,
+                void *data,
+                void *userdata) {
+
+        struct rlimit **rl = data;
+        rlim_t useconds;
+        int r;
+
+        assert(filename);
+        assert(lvalue);
+        assert(rvalue);
+        assert(data);
+
+        rl += ltype;
+
+        if (streq(rvalue, "infinity"))
+                useconds = RLIM_INFINITY;
+        else {
+                usec_t t;
+
+                r = parse_time(rvalue, &t, 1);
+                if (r < 0) {
+                        log_syntax(unit, LOG_ERR, filename, line, r, "Failed to parse resource value, ignoring: %s", rvalue);
+                        return 0;
+                }
+
+                if (t == USEC_INFINITY)
+                        useconds = RLIM_INFINITY;
+                else
+                        useconds = (rlim_t) t;
+        }
+
+        if (!*rl) {
+                *rl = new(struct rlimit, 1);
+                if (!*rl)
+                        return log_oom();
+        }
+
+        (*rl)->rlim_cur = (*rl)->rlim_max = useconds;
+        return 0;
+}
+
 #ifdef HAVE_SYSV_COMPAT
 int config_parse_sysv_priority(const char *unit,
                                const char *filename,
diff --git a/src/core/load-fragment.h b/src/core/load-fragment.h
index 029775bb46..0cf821289c 100644
--- a/src/core/load-fragment.h
+++ b/src/core/load-fragment.h
@@ -57,6 +57,8 @@ int config_parse_exec_secure_bits(const char *unit, const char *filename, unsign
 int config_parse_bounding_set(const char *unit, const char *filename, unsigned line, const char *section, unsigned section_line, const char *lvalue, int ltype, const char *rvalue, void *data, void *userdata);
 int config_parse_limit(const char *unit, const char *filename, unsigned line, const char *section, unsigned section_line, const char *lvalue, int ltype, const char *rvalue, void *data, void *userdata);
 int config_parse_bytes_limit(const char *unit, const char *filename, unsigned line, const char *section, unsigned section_line, const char *lvalue, int ltype, const char *rvalue, void *data, void *userdata);
+int config_parse_sec_limit(const char *unit, const char *filename, unsigned line, const char *section, unsigned section_line, const char *lvalue, int ltype, const char *rvalue, void *data, void *userdata);
+int config_parse_usec_limit(const char *unit, const char *filename, unsigned line, const char *section, unsigned section_line, const char *lvalue, int ltype, const char *rvalue, void *data, void *userdata);
 int config_parse_sysv_priority(const char *unit, const char *filename, unsigned line, const char *section, unsigned section_line, const char *lvalue, int ltype, const char *rvalue, void *data, void *userdata);
 int config_parse_kill_signal(const char *unit, const char *filename, unsigned line, const char *section, unsigned section_line, const char *lvalue, int ltype, const char *rvalue, void *data, void *userdata);
 int config_parse_exec_mount_flags(const char *unit, const char *filename, unsigned line, const char *section, unsigned section_line, const char *lvalue, int ltype, const char *rvalue, void *data, void *userdata);
diff --git a/src/test/test-unit-file.c b/src/test/test-unit-file.c
index f9107e0d0d..3648ec9c58 100644
--- a/src/test/test-unit-file.c
+++ b/src/test/test-unit-file.c
@@ -681,6 +681,66 @@ static void test_config_parse_bounding_set(void) {
         assert_se(capability_bounding_set_drop == ~(make_cap(CAP_NET_RAW) | make_cap(CAP_NET_ADMIN)));
 }
 
+static void test_config_parse_rlimit(void) {
+        struct rlimit * rl[_RLIMIT_MAX] = {};
+
+        assert_se(config_parse_limit(NULL, "fake", 1, "section", 1, "LimitNOFILE", RLIMIT_NOFILE, "55", rl, NULL) >= 0);
+        assert_se(rl[RLIMIT_NOFILE]);
+        assert_se(rl[RLIMIT_NOFILE]->rlim_cur == 55);
+        assert_se(rl[RLIMIT_NOFILE]->rlim_cur == rl[RLIMIT_NOFILE]->rlim_max);
+
+        assert_se(config_parse_limit(NULL, "fake", 1, "section", 1, "LimitNOFILE", RLIMIT_NOFILE, "infinity", rl, NULL) >= 0);
+        assert_se(rl[RLIMIT_NOFILE]);
+        assert_se(rl[RLIMIT_NOFILE]->rlim_cur == RLIM_INFINITY);
+        assert_se(rl[RLIMIT_NOFILE]->rlim_cur == rl[RLIMIT_NOFILE]->rlim_max);
+
+        rl[RLIMIT_NOFILE] = mfree(rl[RLIMIT_NOFILE]);
+
+        assert_se(config_parse_sec_limit(NULL, "fake", 1, "section", 1, "LimitCPU", RLIMIT_CPU, "56", rl, NULL) >= 0);
+        assert_se(rl[RLIMIT_CPU]);
+        assert_se(rl[RLIMIT_CPU]->rlim_cur == 56);
+        assert_se(rl[RLIMIT_CPU]->rlim_cur == rl[RLIMIT_CPU]->rlim_max);
+
+        assert_se(config_parse_sec_limit(NULL, "fake", 1, "section", 1, "LimitCPU", RLIMIT_CPU, "57s", rl, NULL) >= 0);
+        assert_se(rl[RLIMIT_CPU]);
+        assert_se(rl[RLIMIT_CPU]->rlim_cur == 57);
+        assert_se(rl[RLIMIT_CPU]->rlim_cur == rl[RLIMIT_CPU]->rlim_max);
+
+        assert_se(config_parse_sec_limit(NULL, "fake", 1, "section", 1, "LimitCPU", RLIMIT_CPU, "infinity", rl, NULL) >= 0);
+        assert_se(rl[RLIMIT_CPU]);
+        assert_se(rl[RLIMIT_CPU]->rlim_cur == RLIM_INFINITY);
+        assert_se(rl[RLIMIT_CPU]->rlim_cur == rl[RLIMIT_CPU]->rlim_max);
+
+        assert_se(config_parse_sec_limit(NULL, "fake", 1, "section", 1, "LimitCPU", RLIMIT_CPU, "1234ms", rl, NULL) >= 0);
+        assert_se(rl[RLIMIT_CPU]);
+        assert_se(rl[RLIMIT_CPU]->rlim_cur == 2);
+        assert_se(rl[RLIMIT_CPU]->rlim_cur == rl[RLIMIT_CPU]->rlim_max);
+
+        rl[RLIMIT_CPU] = mfree(rl[RLIMIT_CPU]);
+
+        assert_se(config_parse_usec_limit(NULL, "fake", 1, "section", 1, "LimitRTTIME", RLIMIT_RTTIME, "58", rl, NULL) >= 0);
+        assert_se(rl[RLIMIT_RTTIME]);
+        assert_se(rl[RLIMIT_RTTIME]->rlim_cur == 58);
+        assert_se(rl[RLIMIT_RTTIME]->rlim_cur == rl[RLIMIT_RTTIME]->rlim_max);
+
+        assert_se(config_parse_usec_limit(NULL, "fake", 1, "section", 1, "LimitRTTIME", RLIMIT_RTTIME, "59s", rl, NULL) >= 0);
+        assert_se(rl[RLIMIT_RTTIME]);
+        assert_se(rl[RLIMIT_RTTIME]->rlim_cur == 59 * USEC_PER_SEC);
+        assert_se(rl[RLIMIT_RTTIME]->rlim_cur == rl[RLIMIT_RTTIME]->rlim_max);
+
+        assert_se(config_parse_usec_limit(NULL, "fake", 1, "section", 1, "LimitRTTIME", RLIMIT_RTTIME, "infinity", rl, NULL) >= 0);
+        assert_se(rl[RLIMIT_RTTIME]);
+        assert_se(rl[RLIMIT_RTTIME]->rlim_cur == RLIM_INFINITY);
+        assert_se(rl[RLIMIT_RTTIME]->rlim_cur == rl[RLIMIT_RTTIME]->rlim_max);
+
+        assert_se(config_parse_usec_limit(NULL, "fake", 1, "section", 1, "LimitRTTIME", RLIMIT_RTTIME, "2345ms", rl, NULL) >= 0);
+        assert_se(rl[RLIMIT_RTTIME]);
+        assert_se(rl[RLIMIT_RTTIME]->rlim_cur == 2345 * USEC_PER_MSEC);
+        assert_se(rl[RLIMIT_RTTIME]->rlim_cur == rl[RLIMIT_RTTIME]->rlim_max);
+
+        rl[RLIMIT_RTTIME] = mfree(rl[RLIMIT_RTTIME]);
+}
+
 int main(int argc, char *argv[]) {
         int r;
 
@@ -690,6 +750,7 @@ int main(int argc, char *argv[]) {
         r = test_unit_file_get_set();
         test_config_parse_exec();
         test_config_parse_bounding_set();
+        test_config_parse_rlimit();
         test_load_env_file_1();
         test_load_env_file_2();
         test_load_env_file_3();