On Fri, 26 Aug 2022 14:58:39 +1000
David Gibson <david(a)gibson.dropbear.id.au> wrote:
When not given an existing PID or network
namspace to attach to, pasta
spawns a shell. Most commands which can spawn a shell in an altered
environment can also run other commands in that same environment, which can
be useful in automation.
Allow pasta to do the same thing; it can be given an arbitrary command to
run in the network and user namespace which pasta creates. If neither a
command nor an existing PID or netns to attach to is given, continue to
spawn a default shell, as before.
Signed-off-by: David Gibson <david(a)gibson.dropbear.id.au>
---
conf.c | 27 ++++++++++++++++++---------
passt.1 | 14 +++++++++-----
pasta.c | 33 +++++++++++++++++++++++----------
pasta.h | 2 +-
4 files changed, 51 insertions(+), 25 deletions(-)
diff --git a/conf.c b/conf.c
index 2a18124..162c2dd 100644
--- a/conf.c
+++ b/conf.c
@@ -550,7 +550,8 @@ static int conf_ns_pid(char *userns, char *netns, const char *arg)
return 0;
}
- return -EINVAL;
+ /* Not a PID, later code will treat as a command */
+ return 0;
}
/**
@@ -1480,14 +1481,18 @@ void conf(struct ctx *c, int argc, char **argv)
check_root(c);
- if (c->mode == MODE_PASTA && optind + 1 == argc) {
- ret = conf_ns_pid(userns, netns, argv[optind]);
- if (ret < 0)
+ if (c->mode == MODE_PASTA) {
+ if (*netns && optind != argc) {
+ err("Both --netns and PID or command given");
usage(argv[0]);
- } else if (c->mode == MODE_PASTA && *userns
- && !*netns && optind == argc) {
- err("--userns requires --netns or PID");
- usage(argv[0]);
+ } else if (optind + 1 == argc) {
+ ret = conf_ns_pid(userns, netns, argv[optind]);
+ if (ret < 0)
+ usage(argv[0]);
+ } else if (*userns && !*netns && optind == argc) {
+ err("--userns requires --netns or PID");
+ usage(argv[0]);
+ }
} else if (optind != argc) {
usage(argv[0]);
}
[...]
I haven't really looked into this yet, but I guess we should now
handle getopts return codes a bit differently, because this works:
$ ./pasta --config-net -- sh -c 'sleep 1; ip li sh'
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN mode DEFAULT
group default qlen 1000
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
2: enp9s0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 65520 qdisc pfifo_fast state
UNKNOWN mode DEFAULT group default qlen 1000
link/ether aa:3e:39:5f:c6:15 brd ff:ff:ff:ff:ff:ff
while this doesn't:
$ ./pasta --config-net sh -c 'sleep 1; ip li sh'
./pasta: invalid option -- 'c'
[...]
despite the fact that there's no ambiguity.