[Libvirt-cim] [PATCH 2 of 4] Add get_vnc_sessions() to determine all of the VNC ports available or in use

[Dan Smith]

KR> +static size_t get_vnc_hash_key(unsigned int key)
KR> +{
KR> +  return key % VNC_PORT_MIN;
KR> +}

What happens if I set my guest to VNC port 500?

KR> +static CMPIStatus port_to_str(unsigned int port,
KR> +                              char **port_str)
KR> +{
KR> +        CMPIStatus s = {CMPI_RC_OK, NULL};
KR> +
KR> +        if (asprintf(port_str, "%" PRIu16, port) == -1) {
KR> +                cu_statusf(_BROKER, &s,
KR> +                           CMPI_RC_ERR_FAILED,
KR> +                           "Unable to determine session port");
KR> +        }
KR> +
KR> +        return s;
KR> +}

Hmm, I don't like the idea of alloc'ing strings to store ports.
They're just integers after all :)

KR> +static CMPIStatus port_convert(unsigned int port,
KR> +                               char *in_str,
KR> +                               int *out_port)
KR> +{
KR> +        CMPIStatus s = {CMPI_RC_OK, NULL};
KR> +        char *str = NULL;
KR> +
KR> +        if (in_str == NULL) {
KR> +                s = port_to_str(port, &str);
KR> +                if (s.rc != CMPI_RC_OK)
KR> +                        goto out;
KR> +        } else
KR> +                str = strdup(in_str);
KR> +
KR> +        *out_port = strtol(str, NULL, 0);

I think sscanf() is always a better choice.

KR> +static CMPIStatus get_vnc_sessions(struct vnc_ports *vnc_hash[])
KR> +{
KR> +        CMPIStatus s = {CMPI_RC_OK, NULL};
KR> +        const char *path = PROC_TCP;
KR> +        unsigned int lport = 0;
KR> +        unsigned int rport = 0;
KR> +        FILE *tcp_info;
KR> +        char *line = NULL;
KR> +        size_t len = 0;
KR> +        char *remote_port;
KR> +        int local_port;
KR> +        int index;
KR> +        int val;
KR> +        int ret;
KR> +
KR> +        tcp_info = fopen(path, "r");
KR> +        if (tcp_info== NULL) {
KR> +                cu_statusf(_BROKER, &s,
KR> +                           CMPI_RC_ERR_FAILED,
KR> +                           "Failed to open %s: %m", tcp_info);
KR> +                goto out;
KR> +        }
KR> +
KR> +        if (getline(&line, &len, tcp_info) == -1) {
KR> +                cu_statusf(_BROKER, &s,
KR> +                           CMPI_RC_ERR_FAILED,
KR> +                           "Failed to read from %s", tcp_info);
KR> +                goto out;
KR> +        }
KR> +
KR> +        while (getline(&line, &len, tcp_info) > 0) {
KR> +                ret = sscanf(line, "%d: %*[^:]:%X %*[^:]:%X", &val, &lport,
KR> +                             &rport);
KR> +                if (ret != 3) {
KR> +                        cu_statusf(_BROKER, &s,
KR> +                                   CMPI_RC_ERR_FAILED,
KR> +                                   "Unable to determine active sessions");
KR> +                        goto out;
KR> +                }
KR> +
KR> +                s = port_convert(lport, NULL, &local_port);
KR> +                if (s.rc != CMPI_RC_OK)
KR> +                        goto out;
KR> +
KR> +                if ((local_port < VNC_PORT_MIN) || (local_port > VNC_PORT_MAX))
KR> +                    continue;

Ah, this is good that you check the range to avoid the crash :)

However, do we want to support guests with non-standard ports?  Seems
like we do, so maybe we do need some collision resolution in the hash
logic after all.

-- 
Dan Smith
IBM Linux Technology Center
Open Hypervisor Team
email: danms at us.ibm.com