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agetty: use the "best" interface for \4 and \6 

The issue file escape sequences \4 and \6 prints the host IP when no
interface is specified. That's useless on some virtual machines where
gethostname()+getaddrinfo() returns 127.0.0.1.

The seems better to print IP of the "best" interface (UP, RUNNING, non-LOOPBACK)
and use gethostname() as painful fallback only.

Addresses: https://bugzilla.redhat.com/show_bug.cgi?id=1090935
Signed-off-by: Karel Zak <kzak@redhat.com>
This commit is contained in:
Karel Zak 2014-05-13 15:07:08 +02:00
parent 9e147794ca
commit 0f283438bf
2 changed files with 74 additions and 49 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

9
term-utils/agetty.8
View File

@ -305,12 +305,13 @@ followed by one of the letters explained below.
.TP
4 or 4{interface}
Insert the IPv4 address of the machine hostname or IPv4 address the configured
network interface if the interface argument is specified (e.g. \\4{eth0}).
Insert the IPv4 address the specified network interface (e.g. \\4{eth0})
and if the interface argument is not specified then select the first fully
configured (UP, non-LOCALBACK, RUNNING) interface. If not found any
configured interface fall back to IP address of the machine hostname.
.TP
6 or 6{interface}
Insert the IPv6 address of the machine hostname or IPv6 address the configured
network interface if the interface argument is specified (e.g. \\6{eth0}}
The same as \\4 but for IPv6.
.TP
b
Insert the baudrate of the current line.

114
term-utils/agetty.c
View File

@ -34,6 +34,7 @@
#include <arpa/inet.h>
#include <netdb.h>
#include <ifaddrs.h>
#include <net/if.h>
#include "strutils.h"
#include "all-io.h"
@ -1952,41 +1953,70 @@ static void log_warn(const char *fmt, ...)
va_end(ap);
}
static void output_iface_ip(struct ifaddrs *addrs, const char *iface, sa_family_t family)
static void print_addr(sa_family_t family, void *addr)
{
if (!iface)
return;
char buff[INET6_ADDRSTRLEN + 1];
if (addrs->ifa_name
&& strcmp(addrs->ifa_name, iface) == 0
&& addrs->ifa_addr
&& addrs->ifa_addr->sa_family == family) {
void *addr = NULL;
char buff[INET6_ADDRSTRLEN + 1];
switch (addrs->ifa_addr->sa_family) {
case AF_INET:
addr = &((struct sockaddr_in *) addrs->ifa_addr)->sin_addr;
break;
case AF_INET6:
addr = &((struct sockaddr_in6 *) addrs->ifa_addr)->sin6_addr;
break;
}
if (addr) {
inet_ntop(addrs->ifa_addr->sa_family, addr, buff, sizeof(buff));
printf("%s", buff);
}
} else if (addrs->ifa_next)
output_iface_ip(addrs->ifa_next, iface, family);
inet_ntop(family, addr, buff, sizeof(buff));
printf("%s", buff);
}
static void output_ip(sa_family_t family)
/*
* Prints IP for the specified interface (@iface), if the interface is not
* specified then prints the "best" one (UP, RUNNING, non-LOOPBACK). If not
* found the "best" interface then prints at least host IP.
*/
static void output_iface_ip(struct ifaddrs *addrs,
const char *iface,
sa_family_t family)
{
char *host;
struct ifaddrs *p;
struct addrinfo hints, *info = NULL;
char *host = NULL;
void *addr = NULL;
if (!addrs)
return;
for (p = addrs; p; p = p->ifa_next) {
if (!p->ifa_name ||
!p->ifa_addr ||
p->ifa_addr->sa_family != family)
continue;
if (iface) {
/* Filter out by interface name */
if (strcmp(p->ifa_name, iface) != 0)
continue;
} else {
/* Select the "best" interface */
if ((p->ifa_flags & IFF_LOOPBACK) ||
!(p->ifa_flags & IFF_UP) ||
!(p->ifa_flags & IFF_RUNNING))
continue;
}
addr = NULL;
switch (p->ifa_addr->sa_family) {
case AF_INET:
addr = &((struct sockaddr_in *) p->ifa_addr)->sin_addr;
break;
case AF_INET6:
addr = &((struct sockaddr_in6 *) p->ifa_addr)->sin6_addr;
break;
}
if (addr) {
print_addr(family, addr);
return;
}
}
if (iface)
return;
/* Hmm.. not found the best interface, print host IP at least */
memset(&hints, 0, sizeof(hints));
hints.ai_family = family;
if (family == AF_INET6)
@ -1994,9 +2024,6 @@ static void output_ip(sa_family_t family)
host = xgethostname();
if (host && getaddrinfo(host, NULL, &hints, &info) == 0 && info) {
void *addr = NULL;
switch (info->ai_family) {
case AF_INET:
addr = &((struct sockaddr_in *) info->ai_addr)->sin_addr;
@ -2005,12 +2032,8 @@ static void output_ip(sa_family_t family)
addr = &((struct sockaddr_in6 *) info->ai_addr)->sin6_addr;
break;
}
if (addr) {
char buff[INET6_ADDRSTRLEN + 1];
inet_ntop(info->ai_family, (void *) addr, buff, sizeof(buff));
printf("%s", buff);
}
if (addr)
print_addr(family, addr);
freeaddrinfo(info);
}
@ -2175,17 +2198,18 @@ static void output_special_char(unsigned char c, struct options *op,
case '6':
{
sa_family_t family = c == '4' ? AF_INET : AF_INET6;
struct ifaddrs *addrs = NULL;
char iface[128];
if (get_escape_argument(fp, iface, sizeof(iface))) { /* interface IP */
struct ifaddrs *addrs;
int status = getifaddrs(&addrs);
if (status != 0)
break;
if (getifaddrs(&addrs))
break;
if (get_escape_argument(fp, iface, sizeof(iface)))
output_iface_ip(addrs, iface, family);
freeifaddrs(addrs);
} else /* host IP */
output_ip(family);
else
output_iface_ip(addrs, NULL, family);
freeifaddrs(addrs);
break;
}
default: