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From: Stefano Brivio <sbrivio@redhat.com>
To: David Gibson <david@gibson.dropbear.id.au>
Cc: passt-dev@passt.top
Subject: Re: [PATCH 06/14] nstool: Detect what namespaces target is in
Date: Wed, 5 Apr 2023 13:58:25 +0200	[thread overview]
Message-ID: <20230405135825.13e18482@elisabeth> (raw)
In-Reply-To: <20230404014638.3225556-7-david@gibson.dropbear.id.au>

On Tue,  4 Apr 2023 11:46:30 +1000
David Gibson <david@gibson.dropbear.id.au> wrote:

> Give nstool the ability to detect what namespaces the target process is in,
> relative to where it's called.  That is, those namespace types for which
> the target is not in the same namespace as the caller.  For now, just
> print this information with "info", which can be useful for debugging.
> 
> Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
> ---
>  test/nstool.c | 154 +++++++++++++++++++++++++++++++++++++++++++++-----
>  1 file changed, 140 insertions(+), 14 deletions(-)
> 
> diff --git a/test/nstool.c b/test/nstool.c
> index 2cb4fb3..428c9c4 100644
> --- a/test/nstool.c
> +++ b/test/nstool.c
> @@ -15,8 +15,13 @@
>  #include <errno.h>
>  #include <unistd.h>
>  #include <getopt.h>
> +#include <stdarg.h>
>  #include <sys/socket.h>
>  #include <linux/un.h>
> +#include <linux/limits.h>
> +#include <sched.h>
> +
> +#define	ARRAY_SIZE(a)	((int)(sizeof(a) / sizeof((a)[0])))
>  
>  #define die(...)				\
>  	do {					\
> @@ -24,6 +29,28 @@
>  		exit(1);			\
>  	} while (0)
>  
> +struct ns_type {
> +	int flag;
> +	const char *name;
> +};
> +
> +const struct ns_type nstypes[] = {
> +	{ CLONE_NEWCGROUP, "cgroup" },
> +	{ CLONE_NEWIPC, "ipc" },
> +	{ CLONE_NEWNET, "net" },
> +	{ CLONE_NEWNS, "mnt" },
> +	{ CLONE_NEWPID, "pid" },
> +	{ CLONE_NEWTIME, "time" },
> +	{ CLONE_NEWUSER, "user" },
> +	{ CLONE_NEWUTS, "uts" },
> +};
> +
> +struct holder_info {
> +	pid_t pid;
> +	uid_t uid;
> +	gid_t gid;
> +};
> +
>  static void usage(void)
>  {
>  	die("Usage:\n"
> @@ -41,12 +68,16 @@ static void usage(void)
>  	    "    terminate.\n");
>  }
>  
> -static int connect_ctl(const char * sockpath, bool wait)
> +static int connect_ctl(const char *sockpath, bool wait,
> +		       struct holder_info *info,
> +		       struct ucred *peercred)
>  {
>  	int fd = socket(AF_UNIX, SOCK_STREAM, PF_UNIX);
>  	struct sockaddr_un addr = {
>  		.sun_family = AF_UNIX,
>  	};
> +	struct holder_info discard;
> +	ssize_t len;
>  	int rc;
>  
>  	if (fd < 0)
> @@ -61,6 +92,25 @@ static int connect_ctl(const char * sockpath, bool wait)
>  			die("connect() to %s: %s\n", sockpath, strerror(errno));
>  	} while (rc < 0);
>  
> +	if (!info)
> +		info = &discard;

As you close the socket anyway moments later, I wonder if it wouldn't
be doable (and more natural) to just do:

	if (info) {
		len = read(fd, info, sizeof(*info));
		...
	}

	if (peercred) {
		...
	}

...but maybe it adds unnecessary complication to 7/14 (or perhaps the
magic is not really part of 'info'?).

-- 
Stefano


  reply	other threads:[~2023-04-05 11:58 UTC|newest]

Thread overview: 36+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-04-04  1:46 [PATCH 00/14] Improved tool for testing across multiple namespaces David Gibson
2023-04-04  1:46 ` [PATCH 01/14] nstool: Rename nsholder to nstool David Gibson
2023-04-04  1:46 ` [PATCH 02/14] nstool: Reverse parameters " David Gibson
2023-04-04  1:46 ` [PATCH 03/14] nstool: Move description of its operation modes from comment to usage David Gibson
2023-04-05 11:56   ` Stefano Brivio
2023-04-06  0:10     ` David Gibson
2023-04-04  1:46 ` [PATCH 04/14] nstool: Split some command line parsing and socket setup to subcommands David Gibson
2023-04-05 11:58   ` Stefano Brivio
2023-04-06  2:31     ` David Gibson
2023-04-06  6:47       ` Stefano Brivio
2023-04-06 10:35         ` David Gibson
2023-04-04  1:46 ` [PATCH 05/14] nstool: Replace "pid" subcommand with "info" subcommand David Gibson
2023-04-05 11:58   ` Stefano Brivio
2023-04-06  0:13     ` David Gibson
2023-04-04  1:46 ` [PATCH 06/14] nstool: Detect what namespaces target is in David Gibson
2023-04-05 11:58   ` Stefano Brivio [this message]
2023-04-06  0:15     ` David Gibson
2023-04-04  1:46 ` [PATCH 07/14] nstool: Add magic number to advertized information David Gibson
2023-04-05 11:58   ` Stefano Brivio
2023-04-06  0:18     ` David Gibson
2023-04-04  1:46 ` [PATCH 08/14] nstool: Helpers to iterate through namespace types David Gibson
2023-04-05 11:58   ` Stefano Brivio
2023-04-06  0:55     ` David Gibson
2023-04-04  1:46 ` [PATCH 09/14] nstool: Add nstool exec command to execute commands in an nstool namespace David Gibson
2023-04-05 11:58   ` Stefano Brivio
2023-04-06  0:59     ` David Gibson
2023-04-04  1:46 ` [PATCH 10/14] nstool: Add --keep-caps option to nstool exec David Gibson
2023-04-05 11:59   ` Stefano Brivio
2023-04-06  1:11     ` David Gibson
2023-04-04  1:46 ` [PATCH 11/14] test: Initialise ${TRACE} properly David Gibson
2023-04-04  1:46 ` [PATCH 12/14] test: Use "nstool exec" to slightly simplify tests David Gibson
2023-04-05 11:59   ` Stefano Brivio
2023-04-06  1:14     ` David Gibson
2023-04-04  1:46 ` [PATCH 13/14] nstool: Advertise the holder's cwd (in its mountns) across the socket David Gibson
2023-04-04  1:46 ` [PATCH 14/14] nstool: Enter holder's cwd when changing mount ns with nstool exec David Gibson
2023-04-05 12:01 ` [PATCH 00/14] Improved tool for testing across multiple namespaces Stefano Brivio

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