On Fri, Apr 13, 2007 at 11:07:58AM +0200, Dejan Muhamedagic wrote:
> On Fri, Apr 13, 2007 at 04:02:37PM +0900, Simon Horman wrote:
> > If for some reason the file being scanned is malformed, or
> > overflows one of the feilds for some reason, scanf will neither
> > return EOF nor fill in all of its parameters correctly. In the
> > case that I observed this resulted in an endless loop.
> >
> > This simple fix just bails out in this case.
> > Perhaps an error message is in order?
>
> yes, /proc might change. perhaps sth like:
>
> for( ;; ) {
> c=fscanf(...);
> if( c == EOF )
> break;
> else if( c != 13 )
> }
>
> besides, having such a large fscanf in a while test looks ugly.
I agree, though I'm not sure if the version below improves
the code's beuaty in any way.
--
Horms
H: http://www.vergenet.net/~horms/
W: http://www.valinux.co.jp/en/
Subject: [IPv6addr] Merge duplicated code from find_if() and get_if() into
scan_if()
I notice that find_if() and get_if() share a non-trivial amount of code.
The only difference between these two functions is that the latter
constructs and uses a mask, whereas the former only looks for an exact
match. By creating a new function scan_if(), with a switch telling
it weather or not to construct a mask based on the prefix - the default
mask is all 1s, or in otherwords an exact match - the code
duplication is removed.
Index: heartbeat-ipv6addr/resources/OCF/IPv6addr.c
===================================================================
--- heartbeat-ipv6addr.orig/resources/OCF/IPv6addr.c 2007-04-13
15:47:38.000000000 +0900
+++ heartbeat-ipv6addr/resources/OCF/IPv6addr.c 2007-04-13 15:47:41.000000000
+0900
@@ -158,6 +158,8 @@
int create_pid_directory(const char *pid_file);
static void byebye(int nsig);
+static char* scan_if(struct in6_addr* addr_target, int* plen_target,
+ int use_mask);
static char* find_if(struct in6_addr* addr_target, int* plen_target);
static char* get_if(struct in6_addr* addr_target, int* plen_target);
static int assign_addr6(struct in6_addr* addr6, int prefix_len, char* if_name);
@@ -425,9 +427,9 @@
return status;
}
-/* find a proper network interface to assign the address */
+/* find the network interface associated with an address */
char*
-find_if(struct in6_addr* addr_target, int* plen_target)
+scan_if(struct in6_addr* addr_target, int* plen_target, int use_mask)
{
FILE *f;
char addr6[40];
@@ -477,7 +479,7 @@
/* Make the mask based on prefix length */
memset(mask.s6_addr, 0xff, 16);
- if (plen < 128) {
+ if (use_mask && plen < 128) {
n = plen / 8;
memset(mask.s6_addr + n + 1, 0, 15 - n);
s = 8 - plen % 8;
@@ -503,57 +505,17 @@
fclose(f);
return NULL;
}
+/* find a proper network interface to assign the address */
+char*
+find_if(struct in6_addr* addr_target, int* plen_target)
+{
+ return scan_if(addr_target, plen_target, 1);
+}
/* get the device name and the plen_target of a special address */
char*
get_if(struct in6_addr* addr_target, int* plen_target)
{
- FILE *f;
- char addr6[40];
- static char devname[20]="";
- struct in6_addr addr;
- unsigned int plen, scope, dad_status, if_idx;
- char addr6p[8][5];
-
- /* open /proc/net/if_inet6 file */
- if ((f = fopen(IF_INET6, "r")) == NULL) {
- return NULL;
- }
- /* loop for each entry */
- while ( fscanf(f,"%4s%4s%4s%4s%4s%4s%4s%4s %02x %02x %02x %02x %20s\n",
- addr6p[0], addr6p[1], addr6p[2], addr6p[3],
- addr6p[4], addr6p[5], addr6p[6], addr6p[7],
- &if_idx, &plen, &scope, &dad_status, devname) != EOF) {
-
- sprintf(addr6, "%s:%s:%s:%s:%s:%s:%s:%s",
- addr6p[0], addr6p[1], addr6p[2], addr6p[3],
- addr6p[4], addr6p[5], addr6p[6], addr6p[7]);
-
- /* Only Global address entry would be considered.
- * maybe change
- */
- if (0 != scope) {
- continue;
- }
-
- /* "if" specified prefix, only same prefix entry
- * would be considered.
- */
- if (*plen_target!=0 && plen != *plen_target) {
- continue;
- }
- *plen_target = plen;
-
- /* Convert to sockaddr_in6 */
- inet_pton(AF_INET6, addr6, &addr);
-
- /* We found it! */
- if (0 == memcmp(&addr, addr_target,sizeof(addr))) {
- fclose(f);
- return devname;
- }
- }
- fclose(f);
- return NULL;
+ return scan_if(addr_target, plen_target, 0);
}
int
assign_addr6(struct in6_addr* addr6, int prefix_len, char* if_name)
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