ps: stop using AT_CLKTCK, there are more standard ways
function old new delta
ps_main 537 558 +21
func_time 66 59 -7
get_kernel_HZ 102 - -102
------------------------------------------------------------------------------
(add/remove: 0/1 grow/shrink: 1/1 up/down: 21/-109) Total: -88 bytes
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
diff --git a/procps/ps.c b/procps/ps.c
index e004d25..fab8c81 100644
--- a/procps/ps.c
+++ b/procps/ps.c
@@ -145,12 +145,6 @@
#endif
#if ENABLE_DESKTOP
-
-#include <sys/times.h> /* for times() */
-#ifndef AT_CLKTCK
-# define AT_CLKTCK 17
-#endif
-
/* TODO:
* http://pubs.opengroup.org/onlinepubs/9699919799/utilities/ps.html
* specifies (for XSI-conformant systems) following default columns
@@ -187,7 +181,9 @@
char *buffer;
unsigned terminal_width;
#if ENABLE_FEATURE_PS_TIME
+# if ENABLE_FEATURE_PS_UNUSUAL_SYSTEMS || !defined(__linux__)
unsigned kernel_HZ;
+# endif
unsigned long seconds_since_boot;
#endif
} FIX_ALIASING;
@@ -198,92 +194,15 @@
#define need_flags (G.need_flags )
#define buffer (G.buffer )
#define terminal_width (G.terminal_width )
-#define kernel_HZ (G.kernel_HZ )
#define INIT_G() do { setup_common_bufsiz(); } while (0)
#if ENABLE_FEATURE_PS_TIME
-/* for ELF executables, notes are pushed before environment and args */
-/* try "LD_SHOW_AUXV=1 /bin/true" */
-static uintptr_t find_elf_note(uintptr_t findme)
-{
- uintptr_t *ep = (uintptr_t *) environ;
-
- while (*ep++)
- continue;
- while (*ep) {
- if (ep[0] == findme) {
- return ep[1];
- }
- ep += 2;
- }
- return -1;
-}
-
-# if ENABLE_FEATURE_PS_UNUSUAL_SYSTEMS
-static unsigned get_HZ_by_waiting(void)
-{
- struct timeval tv1, tv2;
- unsigned t1, t2, r, hz;
- unsigned cnt = cnt; /* for compiler */
- int diff;
-
- r = 0;
-
- /* Wait for times() to reach new tick */
- t1 = times(NULL);
- do {
- t2 = times(NULL);
- } while (t2 == t1);
- gettimeofday(&tv2, NULL);
-
- do {
- t1 = t2;
- tv1.tv_usec = tv2.tv_usec;
-
- /* Wait exactly one times() tick */
- do {
- t2 = times(NULL);
- } while (t2 == t1);
- gettimeofday(&tv2, NULL);
-
- /* Calculate ticks per sec, rounding up to even */
- diff = tv2.tv_usec - tv1.tv_usec;
- if (diff <= 0) diff += 1000000;
- hz = 1000000u / (unsigned)diff;
- hz = (hz+1) & ~1;
-
- /* Count how many same hz values we saw */
- if (r != hz) {
- r = hz;
- cnt = 0;
- }
- cnt++;
- } while (cnt < 3); /* exit if saw 3 same values */
-
- return r;
-}
+# if ENABLE_FEATURE_PS_UNUSUAL_SYSTEMS || !defined(__linux__)
+# define get_kernel_HZ() (G.kernel_HZ)
# else
-static inline unsigned get_HZ_by_waiting(void)
-{
- /* Better method? */
- return 100;
-}
+ /* non-ancient Linux standardized on 100 for "times" freq */
+# define get_kernel_HZ() ((unsigned)100)
# endif
-
-static unsigned get_kernel_HZ(void)
-{
- if (kernel_HZ)
- return kernel_HZ;
-
- /* Works for ELF only, Linux 2.4.0+ */
- kernel_HZ = find_elf_note(AT_CLKTCK);
- if (kernel_HZ == (unsigned)-1)
- kernel_HZ = get_HZ_by_waiting();
-
- G.seconds_since_boot = get_uptime();
-
- return kernel_HZ;
-}
#endif
/* Print value to buf, max size+1 chars (including trailing '\0') */
@@ -375,26 +294,21 @@
}
#if ENABLE_FEATURE_PS_ADDITIONAL_COLUMNS
-
static void func_rgroup(char *buf, int size, const procps_status_t *ps)
{
safe_strncpy(buf, get_cached_groupname(ps->rgid), size+1);
}
-
static void func_ruser(char *buf, int size, const procps_status_t *ps)
{
safe_strncpy(buf, get_cached_username(ps->ruid), size+1);
}
-
static void func_nice(char *buf, int size, const procps_status_t *ps)
{
sprintf(buf, "%*d", size, ps->niceness);
}
-
#endif
#if ENABLE_FEATURE_PS_TIME
-
static void func_etime(char *buf, int size, const procps_status_t *ps)
{
/* elapsed time [[dd-]hh:]mm:ss; here only mm:ss */
@@ -402,13 +316,11 @@
unsigned ss;
mm = ps->start_time / get_kernel_HZ();
- /* must be after get_kernel_HZ()! */
mm = G.seconds_since_boot - mm;
ss = mm % 60;
mm /= 60;
snprintf(buf, size+1, "%3lu:%02u", mm, ss);
}
-
static void func_time(char *buf, int size, const procps_status_t *ps)
{
/* cumulative time [[dd-]hh:]mm:ss; here only mm:ss */
@@ -420,7 +332,6 @@
mm /= 60;
snprintf(buf, size+1, "%3lu:%02u", mm, ss);
}
-
#endif
#if ENABLE_SELINUX
@@ -627,6 +538,10 @@
};
INIT_G();
+ G.seconds_since_boot = get_uptime();
+#if ENABLE_FEATURE_PS_TIME && (ENABLE_FEATURE_PS_UNUSUAL_SYSTEMS || !defined(__linux__))
+ G.kernel_HZ = bb_clk_tck(); /* this is sysconf(_SC_CLK_TCK) */
+#endif
// POSIX:
// -a Write information for all processes associated with terminals