From: David Gibson <david@gibson.dropbear.id.au>
To: passt-dev@passt.top, Stefano Brivio <sbrivio@redhat.com>
Cc: David Gibson <david@gibson.dropbear.id.au>
Subject: [PATCH v2 4/9] util: Add open_in_ns() helper
Date: Fri, 3 Nov 2023 13:22:58 +1100 [thread overview]
Message-ID: <20231103022303.968638-5-david@gibson.dropbear.id.au> (raw)
In-Reply-To: <20231103022303.968638-1-david@gibson.dropbear.id.au>
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 <david@gibson.dropbear.id.au>
---
util.c | 53 +++++++++++++++++++++++++++++++++++++++++++++++++++++
util.h | 1 +
2 files changed, 54 insertions(+)
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
diff --git a/util.h b/util.h
index 9effc54..78a8fb2 100644
--- a/util.h
+++ b/util.h
@@ -219,6 +219,7 @@ int bitmap_isset(const uint8_t *map, int bit);
char *line_read(char *buf, size_t len, int fd);
void ns_enter(const struct ctx *c);
bool ns_is_init(void);
+int open_in_ns(const struct ctx *c, const char *path, int flags);
void write_pidfile(int fd, pid_t pid);
int __daemon(int pidfile_fd, int devnull_fd);
int fls(unsigned long x);
--
@@ -219,6 +219,7 @@ int bitmap_isset(const uint8_t *map, int bit);
char *line_read(char *buf, size_t len, int fd);
void ns_enter(const struct ctx *c);
bool ns_is_init(void);
+int open_in_ns(const struct ctx *c, const char *path, int flags);
void write_pidfile(int fd, pid_t pid);
int __daemon(int pidfile_fd, int devnull_fd);
int fls(unsigned long x);
--
2.41.0
next prev parent reply other threads:[~2023-11-03 2:23 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-11-03 2:22 [PATCH v2 0/9] Clean ups to automatic port forwarding David Gibson
2023-11-03 2:22 ` [PATCH v2 1/9] conf: Cleaner initialisation of default forwarding modes David Gibson
2023-11-03 2:22 ` [PATCH v2 2/9] port_fwd: Move automatic port forwarding code to port_fwd.[ch] David Gibson
2023-11-03 2:22 ` [PATCH v2 3/9] port_fwd: Better parameterise procfs_scan_listen() David Gibson
2023-11-03 2:22 ` David Gibson [this message]
2023-11-03 2:22 ` [PATCH v2 5/9] port_fwd: Pre-open /proc/net/* files rather than on-demand David Gibson
2023-11-03 2:23 ` [PATCH v2 6/9] port_fwd: Don't NS_CALL get_bound_ports() David Gibson
2023-11-03 2:23 ` [PATCH v2 7/9] port_fwd: Split TCP and UDP cases for get_bound_ports() David Gibson
2023-11-03 2:23 ` [PATCH v2 8/9] port_fwd: Move port scanning /proc fds into struct port_fwd David Gibson
2023-11-03 2:23 ` [PATCH v2 9/9] port_fwd: Simplify get_bound_ports_*() to port_fwd_scan_*() David Gibson
2023-11-07 12:44 ` [PATCH v2 0/9] Clean ups to automatic port forwarding Stefano Brivio
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