From: Stefano Brivio <sbrivio@redhat.com>
To: passt-dev@passt.top
Cc: Callum Parsey <callum@neoninteger.au>,
me@yawnt.com, David Gibson <david@gibson.dropbear.id.au>,
lemmi@nerd2nerd.org, Andrea Arcangeli <aarcange@redhat.com>
Subject: [PATCH v3 02/10] pasta: Improve error handling on failure to join network namespace
Date: Mon, 22 May 2023 19:45:59 +0200 [thread overview]
Message-ID: <20230522174607.2824220-3-sbrivio@redhat.com> (raw)
In-Reply-To: <20230522174607.2824220-1-sbrivio@redhat.com>
In pasta_wait_for_ns(), open() failing with ENOENT is expected: we're
busy-looping until the network namespace appears. But any other
failure is not something we're going to recover from: return right
away if we don't get either success or ENOENT.
Now that pasta_wait_for_ns() can actually fail, handle that in
pasta_start_ns() by reporting the issue and exiting.
Looping on EPERM, when pasta doesn't actually have the permissions to
join a given namespace, isn't exactly a productive thing to do.
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
---
pasta.c | 9 +++++++--
1 file changed, 7 insertions(+), 2 deletions(-)
diff --git a/pasta.c b/pasta.c
index b30ce70..2a6fb60 100644
--- a/pasta.c
+++ b/pasta.c
@@ -95,8 +95,11 @@ static int pasta_wait_for_ns(void *arg)
char ns[PATH_MAX];
snprintf(ns, PATH_MAX, "/proc/%i/ns/net", pasta_child_pid);
- do
- while ((c->pasta_netns_fd = open(ns, flags)) < 0);
+ while ((c->pasta_netns_fd = open(ns, flags)) < 0) {
+ if (errno != ENOENT)
+ return 0;
+ }
+
while (setns(c->pasta_netns_fd, CLONE_NEWNET) &&
!close(c->pasta_netns_fd));
@@ -257,6 +260,8 @@ void pasta_start_ns(struct ctx *c, uid_t uid, gid_t gid,
}
NS_CALL(pasta_wait_for_ns, c);
+ if (c->pasta_netns_fd < 0)
+ die("Failed to join network namespace");
}
/**
--
@@ -95,8 +95,11 @@ static int pasta_wait_for_ns(void *arg)
char ns[PATH_MAX];
snprintf(ns, PATH_MAX, "/proc/%i/ns/net", pasta_child_pid);
- do
- while ((c->pasta_netns_fd = open(ns, flags)) < 0);
+ while ((c->pasta_netns_fd = open(ns, flags)) < 0) {
+ if (errno != ENOENT)
+ return 0;
+ }
+
while (setns(c->pasta_netns_fd, CLONE_NEWNET) &&
!close(c->pasta_netns_fd));
@@ -257,6 +260,8 @@ void pasta_start_ns(struct ctx *c, uid_t uid, gid_t gid,
}
NS_CALL(pasta_wait_for_ns, c);
+ if (c->pasta_netns_fd < 0)
+ die("Failed to join network namespace");
}
/**
--
2.39.2
next prev parent reply other threads:[~2023-05-22 17:46 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-05-22 17:45 [PATCH v3 00/10] Optionally copy all routes and addresses for pasta, allow gateway-less routes Stefano Brivio
2023-05-22 17:45 ` [PATCH v3 01/10] netlink: Fix comment about response buffer size for nl_req() Stefano Brivio
2023-05-22 17:45 ` Stefano Brivio [this message]
2023-05-23 13:47 ` [PATCH v3 02/10] pasta: Improve error handling on failure to join network namespace Stefano Brivio
2023-05-22 17:46 ` [PATCH v3 03/10] netlink: Add functionality to copy routes from outer namespace Stefano Brivio
2023-05-22 17:46 ` [PATCH v3 04/10] conf: --config-net option is for pasta mode only Stefano Brivio
2023-05-22 17:46 ` [PATCH v3 05/10] conf, pasta: With --config-net, copy all routes by default Stefano Brivio
2023-05-23 3:04 ` David Gibson
2023-05-22 17:46 ` [PATCH v3 06/10] Revert "conf: Adjust netmask on mismatch between IPv4 address/netmask and gateway" Stefano Brivio
2023-05-22 17:46 ` [PATCH v3 07/10] conf: Don't exit if sourced default route has no gateway Stefano Brivio
2023-05-22 17:46 ` [PATCH v3 08/10] netlink: Add functionality to copy addresses from outer namespace Stefano Brivio
2023-05-22 17:46 ` [PATCH v3 09/10] conf, pasta: With --config-net, copy all addresses by default Stefano Brivio
2023-05-23 3:05 ` David Gibson
2023-05-22 17:46 ` [PATCH v3 10/10] passt.h: Fix description of pasta_ifi in struct ctx Stefano Brivio
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