[hackers] [ubase] Don't hardcode the buffer size in sysctl || sin

[git]

commit 3803adfd7eb6b85852e89ae186a1e68834ee72ca
Author: sin <s...@2f30.org>
Date:   Thu Apr 17 16:13:34 2014 +0100

    Don't hardcode the buffer size in sysctl

diff --git a/sysctl.c b/sysctl.c
index c6e42ce..43ab5b1 100644
--- a/sysctl.c
+++ b/sysctl.c
@@ -12,9 +12,10 @@ getsysctl(char *variable, char **value)
 {
        char path[PATH_MAX];
        char *p;
-       char *buf;
+       char *buf, c;
        int fd;
        ssize_t n;
+       size_t sz, i;
 
        for (p = variable; *p; p++)
                if (*p == '.')
@@ -28,19 +29,29 @@ getsysctl(char *variable, char **value)
        if (fd < 0)
                return -1;
 
-       buf = malloc(1024);
-       if (!buf) {
-               close(fd);
-               return -1;
-       }
-
-       n = read(fd, buf, 1023);
-       if (n <= 0) {
-               close(fd);
-               free(buf);
-               return -1;
+       i = 0;
+       sz = 1;
+       buf = NULL;
+       while (1) {
+               n = read(fd, &c, 1);
+               if (n < 0) {
+                       close(fd);
+                       free(buf);
+                       return -1;
+               }
+               if (n == 0)
+                       break;
+               if (i == sz - 1) {
+                       sz *= 2;
+                       buf = realloc(buf, sz);
+                       if (!buf) {
+                               close(fd);
+                               return -1;
+                       }
+               }
+               buf[i++] = c;
        }
-       buf[n] = '