i3status/src/print_ip_addr.c
2019-01-23 08:56:40 +01:00

106 lines
2.6 KiB
C

// vim:ts=4:sw=4:expandtab
#include <config.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <netdb.h>
#include <ifaddrs.h>
#include <net/if.h>
#include "i3status.h"
/*
* Return a copy of the .ifa_name field passed as argument where the optional
* IP label, if present, is removed.
*
* example:
* - strip_optional_label("eth0") => "eth0"
* - strip_optional_label("eth0:label") => "eth0"
*
* The memory for the returned string is obtained with malloc(3), and can be
* freed with free(3).
*
*
*/
static char *strip_optional_label(const char *ifa_name) {
char *copy = sstrdup(ifa_name);
char *ptr = strchr(copy, ':');
if (ptr) {
*ptr = '\0';
}
return copy;
}
/*
* Return the IP address for the given interface or "no IP" if the
* interface is up and running but hasn't got an IP address yet
*
*/
const char *get_ip_addr(const char *interface, int family) {
static char part[512];
socklen_t len = 0;
if (family == AF_INET)
len = sizeof(struct sockaddr_in);
else if (family == AF_INET6)
len = sizeof(struct sockaddr_in6);
memset(part, 0, sizeof(part));
struct ifaddrs *ifaddr, *addrp;
bool found = false;
getifaddrs(&ifaddr);
if (ifaddr == NULL)
return NULL;
/* Skip until we are at the input family address of interface */
for (addrp = ifaddr; addrp != NULL; addrp = addrp->ifa_next) {
/* Strip the label if present in the .ifa_name field. */
char *stripped_ifa_name = strip_optional_label(addrp->ifa_name);
bool name_matches = strcmp(stripped_ifa_name, interface) != 0;
free(stripped_ifa_name);
if (name_matches) {
/* The interface does not have the right name, skip it. */
continue;
}
if (addrp->ifa_addr != NULL && addrp->ifa_addr->sa_family == family) {
/* We found the right interface with the right address. */
break;
}
/* Check if the interface is down. If it is, no need to look any
* further. */
if ((addrp->ifa_flags & IFF_RUNNING) == 0) {
freeifaddrs(ifaddr);
return NULL;
}
found = true;
}
if (addrp == NULL) {
freeifaddrs(ifaddr);
return (found ? "no IP" : NULL);
}
int ret;
if ((ret = getnameinfo(addrp->ifa_addr, len, part, sizeof(part), NULL, 0, NI_NUMERICHOST)) != 0) {
fprintf(stderr, "i3status: getnameinfo(): %s\n", gai_strerror(ret));
freeifaddrs(ifaddr);
return "no IP";
}
freeifaddrs(ifaddr);
return part;
}