* [PATCH] getloadavg: use sysinfo() instead of /proc/loadavg
@ 2015-02-24 18:44 Alexander Monakov
2015-02-25 20:51 ` Rich Felker
0 siblings, 1 reply; 2+ messages in thread
From: Alexander Monakov @ 2015-02-24 18:44 UTC (permalink / raw)
To: musl; +Cc: Alexander Monakov
Based on a patch by Szabolcs Nagy.
---
This is a followup to a recent IRC conversation. getloadavg() doesn't really
need to open a file in /proc, since a sysinfo() syscall should suffice. Based
on a patch by nsz, slightly adjusted. Return value of sysinfo() call is not
checked, since the only documented failure is with EFAULT.
src/legacy/getloadavg.c | 18 +++++++-----------
1 file changed, 7 insertions(+), 11 deletions(-)
diff --git a/src/legacy/getloadavg.c b/src/legacy/getloadavg.c
index 43a8c9e..ff06de0 100644
--- a/src/legacy/getloadavg.c
+++ b/src/legacy/getloadavg.c
@@ -1,18 +1,14 @@
#define _GNU_SOURCE
#include <stdlib.h>
-#include <stdio.h>
-#include <string.h>
+#include <sys/sysinfo.h>
int getloadavg(double *a, int n)
{
- int i;
- double b[3];
- FILE *f = fopen("/proc/loadavg", "rbe");
- if (!f) return -1;
- i = fscanf(f, "%lf %lf %lf", b, b+1, b+2);
- fclose(f);
- if (n > i) n = i;
- if (n < 0) return -1;
- memcpy(a, b, n * sizeof *a);
+ struct sysinfo si;
+ if (n <= 0) return n ? -1 : 0;
+ sysinfo(&si);
+ if (n > 3) n = 3;
+ for (int i=0; i<n; i++)
+ a[i] = 1.0/(1<<SI_LOAD_SHIFT) * si.loads[i];
return n;
}
--
2.1.3
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2015-02-24 18:44 [PATCH] getloadavg: use sysinfo() instead of /proc/loadavg Alexander Monakov
2015-02-25 20:51 ` Rich Felker
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