tree-wide: trivial sysconf() invocations tweaks (#42837)

src/basic/env-util.c

@@ -555,7 +555,7 @@ char* strv_env_get_n(char * const *l, const char *name, size_t k, ReplaceEnvFlag
                 const char *t;
 
                 /* Safety check that the name is not overly long, before we do a stack allocation */
-                if (k > (size_t) sysconf(_SC_ARG_MAX) - 2)
+                if (k > sc_arg_max() - 2)
                         return NULL;
 
                 t = strndupa_safe(name, k);

src/basic/memory-util.c

@@ -8,15 +8,14 @@
 
 size_t page_size(void) {
         static thread_local size_t pgsz = 0;
-        long r;
 
         if (_likely_(pgsz > 0))
                 return pgsz;
 
-        r = sysconf(_SC_PAGESIZE);
-        assert(r > 0);
+        long p = sysconf(_SC_PAGESIZE);
+        assert(p > 0);
 
-        pgsz = (size_t) r;
+        pgsz = (size_t) p;
         return pgsz;
 }
 

src/basic/procfs-util.c

@@ -131,7 +131,6 @@ int procfs_cpu_get_usage(nsec_t *ret) {
         _cleanup_free_ char *first_line = NULL;
         unsigned long user_ticks, nice_ticks, system_ticks, irq_ticks, softirq_ticks,
                 guest_ticks = 0, guest_nice_ticks = 0;
-        long ticks_per_second;
         uint64_t sum, gcd, a, b;
         const char *p;
         int r;
@@ -156,10 +155,7 @@ int procfs_cpu_get_usage(nsec_t *ret) {
                    &guest_nice_ticks) < 5) /* we only insist on the first five fields */
                 return -EINVAL;
 
-        ticks_per_second = sysconf(_SC_CLK_TCK);
-        if (ticks_per_second  < 0)
-                return -errno;
-        assert(ticks_per_second > 0);
+        uint64_t ticks_per_second = sysconf_clock_ticks_cached();
 
         sum = (uint64_t) user_ticks + (uint64_t) nice_ticks + (uint64_t) system_ticks +
                 (uint64_t) irq_ticks + (uint64_t) softirq_ticks +
@@ -168,8 +164,8 @@ int procfs_cpu_get_usage(nsec_t *ret) {
         /* Let's reduce this fraction before we apply it to avoid overflows when converting this to μsec */
         gcd = calc_gcd64(NSEC_PER_SEC, ticks_per_second);
 
-        a = (uint64_t) NSEC_PER_SEC / gcd;
-        b = (uint64_t) ticks_per_second / gcd;
+        a = NSEC_PER_SEC / gcd;
+        b = ticks_per_second / gcd;
 
         *ret = DIV_ROUND_UP((nsec_t) sum * (nsec_t) a, (nsec_t) b);
         return 0;

src/basic/time-util.c

@@ -1766,27 +1766,26 @@ int localtime_or_gmtime_usec(
         return 0;
 }
 
-static uint32_t sysconf_clock_ticks_cached(void) {
-        static thread_local uint32_t hz = 0;
-        long r;
+uint64_t sysconf_clock_ticks_cached(void) {
+        static thread_local uint64_t hz = 0;
 
-        if (hz == 0) {
-                r = sysconf(_SC_CLK_TCK);
+        if (hz != 0)
+                return hz;
 
-                assert(r > 0);
-                hz = r;
-        }
+        long t = sysconf(_SC_CLK_TCK);
+        assert(t > 0);
+        hz = (uint64_t) t;
 
         return hz;
 }
 
 uint32_t usec_to_jiffies(usec_t u) {
-        uint32_t hz = sysconf_clock_ticks_cached();
+        uint64_t hz = sysconf_clock_ticks_cached();
         return DIV_ROUND_UP(u, USEC_PER_SEC / hz);
 }
 
 usec_t jiffies_to_usec(uint32_t j) {
-        uint32_t hz = sysconf_clock_ticks_cached();
+        uint64_t hz = sysconf_clock_ticks_cached();
         return DIV_ROUND_UP(j * USEC_PER_SEC, hz);
 }
 

src/basic/time-util.h

@@ -201,6 +201,8 @@ static inline int parse_birth_date(const char *s, struct tm *ret) {
         return parse_calendar_date_full(s, /* allow_pre_epoch= */ true, NULL, ret);
 }
 
+uint64_t sysconf_clock_ticks_cached(void);
+
 uint32_t usec_to_jiffies(usec_t usec);
 usec_t jiffies_to_usec(uint32_t jiffies);
 

src/core/exec-invoke.c

@@ -922,7 +922,7 @@ static int get_supplementary_groups(
          * be positive, otherwise fail.
          */
         errno = 0;
-        int ngroups_max = (int) sysconf(_SC_NGROUPS_MAX);
+        long ngroups_max = sysconf(_SC_NGROUPS_MAX);
         if (ngroups_max <= 0)
                 return errno_or_else(EOPNOTSUPP);
 

src/test/test-condition.c

@@ -1037,7 +1037,8 @@ TEST(condition_test_group) {
         Condition *condition;
         char gid[DECIMAL_STR_MAX(uint32_t)];
         gid_t *gids, max_gid;
-        int ngroups_max, ngroups, r, i;
+        int ngroups, r, i;
+        long ngroups_max;
 
         xsprintf(gid, "%u", UINT32_C(0xFFFF));
         ASSERT_NOT_NULL((condition = condition_new(CONDITION_GROUP, gid, false, false)));