Re: [PATCH 13/17] Tools: hv: Implement the KVP verb - KVP_OP_SET_IP_INFO

Ben Hutchings
2012-07-25T01:25:07Z

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On Tue, 2012-07-24 at 09:01 -0700, K. Y. Srinivasan wrote:
> Implement the KVP verb - KVP_OP_SET_IP_INFO. This operation configures the
> specified interface based on the given configuration. Since configuring
> an interface is very distro specific, we invoke an external script to
> configure the interface.
[...]
> +static int kvp_write_file(FILE *f, char *s1, char *s2, char *s3)
> +{
> + char str[256];
> + int error;
> +
> + memset(str, 0, sizeof(str));
> + strcat(str, s1);
> + if (s2 != NULL)
> + strcat(str, s2);
> + strcat(str, "=");
> + strcat(str, s3);
> + strcat(str, "\n");
> +
> + error = fputs(str, f);

This style of string pasting is crazy; have you never heard of
fprintf()?

[...]
> + /*
> + * Set the configuration for the specified interface with
> + * the information provided. Since there is no standard
> + * way to configure an interface, we will have an external
> + * script that does the job of configuring the interface and
> + * flushing the configuration.
> + *
> + * The parameters passed to this external script are:
> + * 1. A configuration file that has the specified configuration.
> + *
> + * We will embed the name of the interface in the configuration
> + * file: ifcfg-ethx (where ethx is the interface name).
> + *
> + * Here is the format of the ip configuration file:
> + *
> + * HWADDR=macaddr

Is the interface supposed to be matched by name or by MAC address?

> + * BOOTPROTO=dhcp (dhcp enabled for the interface)

The BOOTPROTO line may or may not appear.

> + * NM_CONTROLLED=no (this interface will not be controlled by NM)
> + * PEERDNS=yes

I wonder what the point is of including constant lines in the file.
What is the external script supposed to do if it these apparent
constants change in future?

> + * IPADDR_x=ipaddr
> + * NETMASK_x=netmask
> + * GATEWAY_x=gateway
> + * DNSx=dns

A strangely familiar format...

> + * IPV6 addresses will be tagged as IPV6ADDR, IPV6 gateway will be
> + * tagged as IPV6_DEFAULTGW and IPV6 NETMASK will be tagged as
> + * IPV6NETMASK.
> + */
> +
> + memset(if_file, 0, sizeof(if_file));
> + strcat(if_file, "/var/opt/hyperv/ifcfg-");

Like I said before about the key-value files, this should be under
/var/lib if the daemon is included in a distribution. You should
perhaps use a macro for the "/var/opt" part so it can be overridden
depending on whether it's built as a distribution or add-on package.

> + strcat(if_file, if_name);
> +
> + file = fopen(if_file, "w");
> +
> + if (file == NULL) {
> + syslog(LOG_ERR, "Failed to open config file");
> + return HV_E_FAIL;
> + }
> +
> + /*
> + * First write out the MAC address.
> + */
> +
> + mac_addr = kvp_if_name_to_mac(if_name);
> + if (mac_addr == NULL) {
> + error = HV_E_FAIL;
> + goto setval_error;
> + }
> +
> + error = kvp_write_file(file, "HWADDR", NULL, mac_addr);
> + if (error)
> + goto setval_error;
> +
> + error = kvp_write_file(file, "ONBOOT", NULL, "yes");
> + if (error)
> + goto setval_error;
> +
> + error = kvp_write_file(file, "IPV6INIT", NULL, "yes");
> + if (error)
> + goto setval_error;
[...]

This line isn't mentioned in the above comment.

Ben.

--
Ben Hutchings
If more than one person is responsible for a bug, no one is at fault.

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