[mosquitto-dev] building git develop trip report

[Greg Troxel <gdt@xxxxxxxxxx>]

System is NetBSD 10 amd64, and dependencies that the mosquitto pkgsrc
package needs are installed.

* cJSON required

I just built (cmake) and got an error that cJSON was not found.   That's
easy to install, but README.md says it's optional.  Am guessing it is no
longer optional

* addrinfo used without required header

On NetBSD, getaddrinfo documents needing netdb.h. POSIX
  https://pubs.opengroup.org/onlinepubs/9799919799/functions/freeaddrinfo.html
says

  SYNOPSIS

      #include <sys/socket.h>
      #include <netdb.h>

      void freeaddrinfo(struct addrinfo *ai);
      int getaddrinfo(const char *restrict nodename,
             const char *restrict servname,
             const struct addrinfo *restrict hints,
             struct addrinfo **restrict res);

so e.g.

diff --git a/src/http_api.c b/src/http_api.c
index 00f78c84..4b5d96de 100644
--- a/src/http_api.c
+++ b/src/http_api.c
@@ -21,6 +21,7 @@ Contributors:
 #include <assert.h>
 #include <errno.h>
 #include <microhttpd.h>
+#include <netdb.h>
 #include <string.h>
 #include <sys/stat.h>
 

* libmicrohttpd

  [ 23%] Linking C executable mosquitto
  ld: cannot find -lmicrohttpd
  *** Error code 1

Looking in README.md, I don't find it mentioned.  I'm guessing it's a
new dependency, and just needs to be listed.  Installed from pkgsrc and continuing.

* UB invoked via ctypes(3)

/n0/gdt/SOFTWARE/IOT/MQTT/mosquitto/apps/mosquitto_passwd/mosquitto_passwd.c:398:23: warning: array subscript has type ‘char’ [-Wchar-subscripts]
  398 |    if(iscntrl(username[i])){
      |                       ^

almost certainly needs to be casted to unsigned char; it's an error to
pass an argument of type char to ctype functions, because it might be
signed, and when extended to int might be out of range.

* PATH_MAX

[ 27%] Building C object apps/mosquitto_signal/CMakeFiles/mosquitto_signal.dir/signal_unix.c.o
/n0/gdt/SOFTWARE/IOT/MQTT/mosquitto/apps/mosquitto_signal/signal_unix.c: In function ‘signal_all’:
/n0/gdt/SOFTWARE/IOT/MQTT/mosquitto/apps/mosquitto_signal/signal_unix.c:31:15: error: ‘PATH_MAX’ undeclared (first use in this function)
   31 |  char pathbuf[PATH_MAX+1];
      |               ^~~~~~~~

I'm not sure where POSIX says this is supposed to be.  sys/param.h on
NetBSD.  There is a POSIX API to get config like this; it might be more
portable to just use that.

* gmock

[ 41%] Building CXX object test/mock/CMakeFiles/pthread_mock.dir/pthread_mock.cpp.o
In file included from /n0/gdt/SOFTWARE/IOT/MQTT/mosquitto/test/mock/pthread_mock.cpp:1:
/n0/gdt/SOFTWARE/IOT/MQTT/mosquitto/test/mock/pthread_mock.hpp:3:10: fatal error: gmock/gmock.h: No such file or directory
    3 | #include <gmock/gmock.h>
      |          ^~~~~~~~~~~~~~~
compilation terminated.
*** Error code 1

Not documented in README.md



Pausing now, and I realize this is likely develop's first contact with
non-Linux.  It would be good for someone to build on FreeBSD and
Illumos.