pasta: modify hostname when detaching new namespace

When invoking pasta without any arguments, it's difficult
to tell whether we are in the new namespace or not leaving
users a bit confused. This change modifies the host namespace
to add a prefix "pasta-" to make it a bit more obvious.

Signed-off-by: Danish Prakash <contact@danishpraka.sh>
[sbrivio: coding style fixes]
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
This commit is contained in:
Danish Prakash 2024-07-30 11:31:23 +05:30 committed by Stefano Brivio
parent 8fae3b73cb
commit 0149d11cc5

11
pasta.c
View file

@ -50,6 +50,8 @@
#include "netlink.h" #include "netlink.h"
#include "log.h" #include "log.h"
#define HOSTNAME_PREFIX "pasta-"
/* PID of child, in case we created a namespace */ /* PID of child, in case we created a namespace */
int pasta_child_pid; int pasta_child_pid;
@ -177,6 +179,7 @@ struct pasta_spawn_cmd_arg {
/* cppcheck-suppress [constParameterCallback, unmatchedSuppression] */ /* cppcheck-suppress [constParameterCallback, unmatchedSuppression] */
static int pasta_spawn_cmd(void *arg) static int pasta_spawn_cmd(void *arg)
{ {
char hostname[HOST_NAME_MAX + 1] = HOSTNAME_PREFIX;
const struct pasta_spawn_cmd_arg *a; const struct pasta_spawn_cmd_arg *a;
sigset_t set; sigset_t set;
@ -187,6 +190,14 @@ static int pasta_spawn_cmd(void *arg)
if (write_file("/proc/sys/net/ipv4/ping_group_range", "0 0")) if (write_file("/proc/sys/net/ipv4/ping_group_range", "0 0"))
warn("Cannot set ping_group_range, ICMP requests might fail"); warn("Cannot set ping_group_range, ICMP requests might fail");
if (!gethostname(hostname + sizeof(HOSTNAME_PREFIX) - 1,
HOST_NAME_MAX + 1 - sizeof(HOSTNAME_PREFIX)) ||
errno == ENAMETOOLONG) {
hostname[HOST_NAME_MAX] = '\0';
if (sethostname(hostname, strlen(hostname)))
warn("Unable to set pasta-prefixed hostname");
}
/* Wait for the parent to be ready: see main() */ /* Wait for the parent to be ready: see main() */
sigemptyset(&set); sigemptyset(&set);
sigaddset(&set, SIGUSR1); sigaddset(&set, SIGUSR1);