add to osmo_sock_get_name*() API

Basically, I am applying code review that I would have given had I not been on
vacation when the last osmo_sock_get_name* stuff was merged.

osmo_sock_get_name2() is so far a static internal function. However, it is
nothing like osmo_sock_get_name(), so instead rename it to
osmo_sock_get_ip_and_port(). Also make it public API, no need to hide it.  I'm
adding an "and" in the name to hopefully clarify: "ip_port" vs. "ip_and_port"
-- there already are _get_X_ip_port() functions that only return the port
string, despite "ip" in the name.

Add new public osmo_sock_get_name2(), which is like osmo_sock_get_name(),
except it uses a static string instead of talloc, and omits the braces. This
is most convenient for log statement formats, avoiding dyn allocations.

Add new osmo_sock_get_name_buf(), which is like osmo_sock_get_name2() but
writes to a caller provided char buffer.

Use osmo_sock_get_name_buf() in the implementation of osmo_sock_get_name(),
but use another (non-static) local string buffer, because adding braces is too
complex without talloc_snprintf().

Rationale:

I want to improve the logging of socket errors, e.g. change

  DLMGCP ERROR Failed to read: 111/Connection refused (mgcp_client.c:720)

to

  DLMGCP ERROR Failed to read: r=10.0.99.2:2427<->l=10.0.99.2:2728: 111='Connection refused' (mgcp_client.c:721)

but it is just not handy to compose logging with the current API:

- osmo_sock_get_name() requires a talloc_free().
- all the others require output buffers.
- the only way to conveniently compose a logging string and,
- notably, the only trivial way to skip the string composition if the logging
  level is currently muted, is to have a function that returns a static string:
  the new osmo_sock_get_name2().
- (I think the osmo_sock_get_{local,remote}_* convenience wrappers should never
  have been added, because they encourage the caller to invoke the same code
  twice, for IP addr and port, and throw away one half each time.)

Related: Iae728192f499330d16836d9435648f6b8ed213b6 (osmo-mgw)
Change-Id: I8ad89ac447c9c582742e70d082072bdd40a5a398

1 files changed, 3 insertions, 0 deletions

diff --git a/include/osmocom/core/socket.h b/include/osmocom/core/socket.h
index 79a61bb0..43604ec0 100644
--- a/include/osmocom/core/socket.h
+++ b/include/osmocom/core/socket.h
@@ -60,6 +60,9 @@ int osmo_sock_unix_init_ofd(struct osmo_fd *ofd, uint16_t type, uint8_t proto,
 			    const char *socket_path, unsigned int flags);
 
 char *osmo_sock_get_name(void *ctx, int fd);
+const char *osmo_sock_get_name2(int fd);
+int osmo_sock_get_name_buf(char *str, size_t str_len, int fd);
+int osmo_sock_get_ip_and_port(int fd, char *ip, size_t ip_len, char *port, size_t port_len, bool local);
 int osmo_sock_get_local_ip(int fd, char *host, size_t len);
 int osmo_sock_get_local_ip_port(int fd, char *port, size_t len);
 int osmo_sock_get_remote_ip(int fd, char *host, size_t len);