Fix three uses of bogus errno value in logs (and returned value in one case)

src/activate/activate.c

@@ -186,7 +186,7 @@ static int exec_process(const char* name, char **argv, char **env, int start_fd,
 
                 r = rearrange_stdio(start_fd, start_fd, STDERR_FILENO); /* invalidates start_fd on success + error */
                 if (r < 0)
-                        return log_error_errno(errno, "Failed to move fd to stdin+stdout: %m");
+                        return log_error_errno(r, "Failed to move fd to stdin+stdout: %m");
 
         } else {
                 if (start_fd != SD_LISTEN_FDS_START) {

src/core/bpf-firewall.c

@@ -691,13 +691,14 @@ int bpf_firewall_supported(void) {
                          1,
                          BPF_F_NO_PREALLOC);
         if (fd < 0) {
-                log_debug_errno(r, "Can't allocate BPF LPM TRIE map, BPF firewalling is not supported: %m");
+                log_debug_errno(fd, "Can't allocate BPF LPM TRIE map, BPF firewalling is not supported: %m");
                 return supported = BPF_FIREWALL_UNSUPPORTED;
         }
 
         safe_close(fd);
 
-        if (bpf_program_new(BPF_PROG_TYPE_CGROUP_SKB, &program) < 0) {
+        r = bpf_program_new(BPF_PROG_TYPE_CGROUP_SKB, &program);
+        if (r < 0) {
                 log_debug_errno(r, "Can't allocate CGROUP SKB BPF program, BPF firewalling is not supported: %m");
                 return supported = BPF_FIREWALL_UNSUPPORTED;
         }