From 4f0b9f91e40ac004f955e73860ee1a0eee9cab95 Mon Sep 17 00:00:00 2001 From: David Gibson Date: Fri, 3 Nov 2023 13:22:58 +1100 Subject: util: Add open_in_ns() helper Most of our helpers which need to enter the pasta network namespace are quite specialised. Add one which is rather general - it just open()s a given file in the namespace context and returns the fd back to the main namespace. This will have some future uses. Signed-off-by: David Gibson Signed-off-by: Stefano Brivio --- util.c | 53 +++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 53 insertions(+) (limited to 'util.c') diff --git a/util.c b/util.c index a8f3b35..c38ab7e 100644 --- a/util.c +++ b/util.c @@ -364,6 +364,59 @@ bool ns_is_init(void) return ret; } +/** + * struct open_in_ns_args - Parameters for do_open_in_ns() + * @c: Execution context + * @fd: Filled in with return value from open() + * @err: Filled in with errno if open() failed + * @path: Path to open + * @flags: open() flags + */ +struct open_in_ns_args { + const struct ctx *c; + int fd; + int err; + const char *path; + int flags; +}; + +/** + * do_open_in_ns() - Enter namespace and open a file + * @arg: See struct open_in_ns_args + * + * Must be called via NS_CALL() + */ +static int do_open_in_ns(void *arg) +{ + struct open_in_ns_args *a = (struct open_in_ns_args *)arg; + + ns_enter(a->c); + + a->fd = open(a->path, a->flags); + a->err = errno; + + return 0; +} + +/** + * open_in_ns() - open() within the pasta namespace + * @c: Execution context + * @path: Path to open + * @flags: open() flags + * + * Return: fd of open()ed file or -1 on error, errno is set to indicate error + */ +int open_in_ns(const struct ctx *c, const char *path, int flags) +{ + struct open_in_ns_args arg = { + .c = c, .path = path, .flags = flags, + }; + + NS_CALL(do_open_in_ns, &arg); + errno = arg.err; + return arg.fd; +} + /** * pid_file() - Write PID to file, if requested to do so, and close it * @fd: Open PID file descriptor, closed on exit, -1 to skip writing it -- cgit v1.2.3