From 0149d11cc5043d618cf4a6e6e8201d5718836dd2 Mon Sep 17 00:00:00 2001 From: Danish Prakash Date: Tue, 30 Jul 2024 11:31:23 +0530 Subject: [PATCH] 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 [sbrivio: coding style fixes] Signed-off-by: Stefano Brivio --- pasta.c | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/pasta.c b/pasta.c index 084288c..572048d 100644 --- a/pasta.c +++ b/pasta.c @@ -50,6 +50,8 @@ #include "netlink.h" #include "log.h" +#define HOSTNAME_PREFIX "pasta-" + /* PID of child, in case we created a namespace */ int pasta_child_pid; @@ -177,6 +179,7 @@ struct pasta_spawn_cmd_arg { /* cppcheck-suppress [constParameterCallback, unmatchedSuppression] */ static int pasta_spawn_cmd(void *arg) { + char hostname[HOST_NAME_MAX + 1] = HOSTNAME_PREFIX; const struct pasta_spawn_cmd_arg *a; 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")) 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() */ sigemptyset(&set); sigaddset(&set, SIGUSR1);