When receiving strings *from* msgpack, we don't need to duplicate/free since
the data only lives in the msgpack parse buffer until the end of the call.
But in order to reuse `msgpack_rpc_free_object` when sending event data(which is
sent *to* msgpack), Strings must be freed, which means they must also be
allocated separately.
Relates to issue #760
These coverity warnings are of the form:
>>> CID 62602: Buffer not null terminated (BUFFER_SIZE_WARNING)
>>> Calling strncpy with a maximum size argument of 256 bytes...
This is caused by strncpy not alway NULL-terminated the destination buffer
(for example in the case where strlen(src) >= size(dst)). It's better to
replace that with (x)strlcpy, which always NULL-terminates.
Most of these are related to the set_api_error macro, which uses strncpy.
The error struct is used (for example) in msgpack_rpc_error, where strlen is
executed on it, so it needs to be NULL-terminated. (x)strlcpy, unlike
strncpy, always NULL-terminates the destination buffer.
Relevant parts of the coverity report:
*** CID 62602: Buffer not null terminated (BUFFER_SIZE_WARNING)
/src/nvim/api/vim.c: 236 in vim_set_current_buffer()
230 if (try_end(err)) {
231 return;
232 }
233
234 char msg[256];
235 snprintf(msg, sizeof(msg),
"failed to switch to buffer %d", (int)buffer);
>>> CID 62602: Buffer not null terminated (BUFFER_SIZE_WARNING)
>>> Calling strncpy with a maximum size argument of 256 bytes on
>>> destination array "err->msg" of size 256 bytes might leave the
>>> destination string unterminated.
236 set_api_error(msg, err);
237 return;
238 }
239
240 try_end(err);
241 }
*** CID 62603: Buffer not null terminated (BUFFER_SIZE_WARNING)
/src/nvim/api/private/helpers.c: 70 in try_end()
64 } else if (msg_list != NULL && *msg_list != NULL) {
65 int should_free;
66 char *msg = (char *)get_exception_string(*msg_list,
67 ET_ERROR,
68 NULL,
69 &should_free);
>>> CID 62603: Buffer not null terminated (BUFFER_SIZE_WARNING)
>>> Calling strncpy with a maximum size argument of 256 bytes on
>>> destination array "err->msg" of size 256 bytes might leave the
>>> destination string unterminated.
70 strncpy(err->msg, msg, sizeof(err->msg));
71 err->set = true;
72 free_global_msglist();
73
74 if (should_free) {
75 free(msg);
/src/nvim/api/private/helpers.c: 78 in try_end()
72 free_global_msglist();
73
74 if (should_free) {
75 free(msg);
76 }
77 } else if (did_throw) {
>>> CID 62603: Buffer not null terminated (BUFFER_SIZE_WARNING)
>>> Calling strncpy with a maximum size argument of 256 bytes on
>>> destination array "err->msg" of size 256 bytes might leave the
>>> destination string unterminated.
78 set_api_error((char *)current_exception->value, err);
79 }
80
81 return err->set;
82 }
83
*** CID 62604: Buffer not null terminated (BUFFER_SIZE_WARNING)
/src/nvim/api/private/helpers.c: 592 in set_option_value_err()
586 opt_flags)))
587 {
588 if (try_end(err)) {
589 return;
590 }
591
>>> CID 62604: Buffer not null terminated (BUFFER_SIZE_WARNING)
>>> Calling strncpy with a maximum size argument of 256 bytes on
>>> destination array "err->msg" of size 256 bytes might leave the
>>> destination string unterminated.
592 set_api_error(errmsg, err);
593 }
*** CID 62605: Buffer not null terminated (BUFFER_SIZE_WARNING)
/src/nvim/os/server.c: 114 in server_start()
108 if (addr_len > sizeof(ip) - 1) {
109 // Maximum length of a ip address buffer is 15(eg: 255.255.255.255)
110 addr_len = sizeof(ip);
111 }
112
113 // Extract the address part
>>> CID 62605: Buffer not null terminated (BUFFER_SIZE_WARNING)
>>> Calling strncpy with a maximum size argument of 16 bytes on
>>> destination array "ip" of size 16 bytes might leave the destination
>>> string unterminated.
114 strncpy(ip, addr, addr_len);
115
116 int port = NEOVIM_DEFAULT_TCP_PORT;
117
118 if (*ip_end == ':') {
119 char *port_end;
/src/nvim/os/server.c: 88 in server_start()
82
83 void server_start(char *endpoint, ChannelProtocol prot)
84 {
85 char addr[ADDRESS_MAX_SIZE];
86
87 // Trim to `ADDRESS_MAX_SIZE`
>>> CID 62605: Buffer not null terminated (BUFFER_SIZE_WARNING)
>>> Calling strncpy with a maximum size argument of 256 bytes on
>>> destination array "addr" of size 256 bytes might leave the
>>> destination string unterminated.
88 strncpy(addr, endpoint, sizeof(addr));
89
90 // Check if the server already exists
91 if (map_has(cstr_t)(servers, addr)) {
92 EMSG2("Already listening on %s", addr);
93 return;
*** CID 62606: Buffer not null terminated (BUFFER_SIZE_WARNING)
/src/nvim/os/server.c: 186 in server_stop()
180 void server_stop(char *endpoint)
181 {
182 Server *server;
183 char addr[ADDRESS_MAX_SIZE];
184
185 // Trim to `ADDRESS_MAX_SIZE`
>>> CID 62606: Buffer not null terminated (BUFFER_SIZE_WARNING)
>>> Calling strncpy with a maximum size argument of 256 bytes on
>>> destination array "addr" of size 256 bytes might leave the
>>> destination string unterminated.
187
188 if ((server = map_get(cstr_t)(servers, addr)) == NULL) {
189 EMSG2("Not listening on %s", addr);
190 return;
191 }
- Define specialized arrays for each remote object type
- Implement msgpack_rpc functions for dealing with the new types
- Refactor all functions dealing with buffers, windows and tabpages to
return/accept handles instead of list indexes.
