From c56c1f6c2b683d6f20a7e8caeecec6c3cb76798f Mon Sep 17 00:00:00 2001

From: Lukas Nykryn <lnykryn@redhat.com>

Date: Tue, 3 Jan 2017 14:21:25 +0100

Subject: [PATCH] core: make parsing of RLIMIT_NICE aware of actual nice levels

RHEL-only

(most of code taken from 29857001854a02c292f1f3b324e7a66831e859c8)

Resolves: #1409588

---

 man/systemd.exec.xml                  |  7 ++-

 src/core/load-fragment-gperf.gperf.m4 |  2 +-

 src/core/load-fragment.c              | 72 +++++++++++++++++++++++++++

 src/core/load-fragment.h              |  1 +

 src/core/main.c                       |  2 +-

 5 files changed, 81 insertions(+), 3 deletions(-)

diff --git a/man/systemd.exec.xml b/man/systemd.exec.xml

index 0cd469cd9..c5199d3a5 100644

--- a/man/systemd.exec.xml

+++ b/man/systemd.exec.xml

@@ -575,7 +575,12 @@

         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>

+        multiples of 1s. For <varname>LimitNICE=</varname> the value

+        may be specified in two syntaxes: if prefixed with <literal>+</literal>

+        or <literal>-</literal>, the value is understood as regular Linux

+        nice value in the range -20..19. If not prefixed like this the value

+        is understood as raw resource limit parameter in the range 0..40 (with 0 being

+        equivalent to 1).</para>

         <para>Note that most process resource limits configured with

         these options are per-process, and processes may fork in order

diff --git a/src/core/load-fragment-gperf.gperf.m4 b/src/core/load-fragment-gperf.gperf.m4

index 45d1ead45..f3a6e13d9 100644

--- a/src/core/load-fragment-gperf.gperf.m4

+++ b/src/core/load-fragment-gperf.gperf.m4

@@ -71,7 +71,7 @@ $1.LimitMEMLOCK,                 config_parse_bytes_limit,           RLIMIT_MEML

 $1.LimitLOCKS,                   config_parse_limit,                 RLIMIT_LOCKS,                  offsetof($1, exec_context.rlimit)

 $1.LimitSIGPENDING,              config_parse_limit,                 RLIMIT_SIGPENDING,             offsetof($1, exec_context.rlimit)

 $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.LimitNICE,                    config_parse_nice_limit,            RLIMIT_NICE,                   offsetof($1, exec_context.rlimit)

 $1.LimitRTPRIO,                  config_parse_limit,                 RLIMIT_RTPRIO,                 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)

diff --git a/src/core/load-fragment.c b/src/core/load-fragment.c

index 705641971..3a3c456da 100644

--- a/src/core/load-fragment.c

+++ b/src/core/load-fragment.c

@@ -1154,6 +1154,56 @@ static int rlim_parse_usec(const char *val, rlim_t *res) {

         return r;

 }

+static int rlim_parse_nice(const char *val, rlim_t *ret) {

+        uint64_t rl;

+        int r;

+

+        /* So, Linux is weird. The range for RLIMIT_NICE is 40..1, mapping to the nice levels -20..19. However, the

+         * RLIMIT_NICE limit defaults to 0 by the kernel, i.e. a value that maps to nice level 20, which of course is

+         * bogus and does not exist. In order to permit parsing the RLIMIT_NICE of 0 here we hence implement a slight

+         * asymmetry: when parsing as positive nice level we permit 0..19. When parsing as negative nice level, we

+         * permit -20..0. But when parsing as raw resource limit value then we also allow the special value 0.

+         *

+         * Yeah, Linux is quality engineering sometimes... */

+

+        if (val[0] == '+') {

+

+                /* Prefixed with "+": Parse as positive user-friendly nice value */

+                r = safe_atou64(val + 1, &rl);

+                if (r < 0)

+                        return r;

+

+                if (rl >= PRIO_MAX)

+                        return -ERANGE;

+

+                rl = 20 - rl;

+

+        } else if (val[0] == '-') {

+

+                /* Prefixed with "-": Parse as negative user-friendly nice value */

+                r = safe_atou64(val + 1, &rl);

+                if (r < 0)

+                        return r;

+

+                if (rl > (uint64_t) (-PRIO_MIN))

+                        return -ERANGE;

+

+                rl = 20 + rl;

+        } else {

+

+                /* Not prefixed: parse as raw resource limit value */

+                r = safe_atou64(val, &rl);

+                if (r < 0)

+                        return r;

+

+                if (rl > (uint64_t) (20 - PRIO_MIN))

+                        return -ERANGE;

+        }

+

+        *ret = (rlim_t) rl;

+        return 0;

+}

+

 static int parse_rlimit_range(

                 const char *unit,

                 const char *filename,

@@ -1286,6 +1336,28 @@ int config_parse_usec_limit(

         return parse_rlimit_range(unit, filename, line, rvalue, rl, rlim_parse_usec);

 }

+int config_parse_nice_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;

+

+        assert(filename);

+        assert(lvalue);

+        assert(rvalue);

+        assert(data);

+

+        rl += ltype;

+        return parse_rlimit_range(unit, filename, line, rvalue, rl, rlim_parse_nice);

+}

 #ifdef HAVE_SYSV_COMPAT

 int config_parse_sysv_priority(const char *unit,

diff --git a/src/core/load-fragment.h b/src/core/load-fragment.h

index 611479612..7c69e5369 100644

--- a/src/core/load-fragment.h

+++ b/src/core/load-fragment.h

@@ -59,6 +59,7 @@ int config_parse_limit(const char *unit, const char *filename, unsigned line, co

 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_nice_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/core/main.c b/src/core/main.c

index 6f8367632..820cbc3e5 100644

--- a/src/core/main.c

+++ b/src/core/main.c

@@ -669,7 +669,7 @@ static int parse_config_file(void) {

                 { "Manager", "DefaultLimitLOCKS",         config_parse_limit,            0, &arg_default_rlimit[RLIMIT_LOCKS]      },

                 { "Manager", "DefaultLimitSIGPENDING",    config_parse_limit,            0, &arg_default_rlimit[RLIMIT_SIGPENDING] },

                 { "Manager", "DefaultLimitMSGQUEUE",      config_parse_bytes_limit,      0, &arg_default_rlimit[RLIMIT_MSGQUEUE]   },

-                { "Manager", "DefaultLimitNICE",          config_parse_limit,            0, &arg_default_rlimit[RLIMIT_NICE]       },

+                { "Manager", "DefaultLimitNICE",          config_parse_nice_limit,       0, &arg_default_rlimit[RLIMIT_NICE]       },

                 { "Manager", "DefaultLimitRTPRIO",        config_parse_limit,            0, &arg_default_rlimit[RLIMIT_RTPRIO]     },

                 { "Manager", "DefaultLimitRTTIME",        config_parse_limit,            0, &arg_default_rlimit[RLIMIT_RTTIME]     },

                 { "Manager", "DefaultCPUAccounting",      config_parse_bool,             0, &arg_default_cpu_accounting            },