[hackers] [ubase] Implement streplace() || sin

[git]

commit 0897d999e63be4e2e6e5c385b72a02dd649086ee
Author: sin <s...@2f30.org>
Date:   Thu Apr 17 16:38:31 2014 +0100

    Implement streplace()
    
    Restore variable as early as possible and in error conditions

diff --git a/sysctl.c b/sysctl.c
index e9a3898..6a764e5 100644
--- a/sysctl.c
+++ b/sysctl.c
@@ -7,6 +7,16 @@
 #include <unistd.h>
 #include "util.h"
 
+static void
+streplace(char *s, int a, int b)
+{
+       char *p;
+
+       for (p = s; *p; p++)
+               if (*p == a)
+                       *p = b;
+}
+
 static int
 getsysctl(char *variable, char **value)
 {
@@ -17,13 +27,15 @@ getsysctl(char *variable, char **value)
        ssize_t n;
        size_t sz, i;
 
-       for (p = variable; *p; p++)
-               if (*p == '.')
-                       *p = '/';
+       streplace(variable, '.', '/');
 
        strlcpy(path, "/proc/sys/", sizeof(path));
-       if (strlcat(path, variable, sizeof(path)) >= sizeof(path))
+       if (strlcat(path, variable, sizeof(path)) >= sizeof(path)) {
+               streplace(variable, '/', '.');
                return -1;
+       }
+
+       streplace(variable, '/', '.');
 
        fd = open(path, O_RDONLY);
        if (fd < 0)
@@ -59,10 +71,6 @@ getsysctl(char *variable, char **value)
        if (p)
                *p = '