Re: [libvirt] [PATCH] lxc: do not require 'ifconfig' or 'ipconfig' in container

Quoting Scott Moser (smoser(a)ubuntu.com): > Currently, the lxc implementation invokes 'ip' and 'ifconfig' commands > inside a container using 'virRun'. That has the side effect of requiring > those commands to be present and to function in a manner consistent with > the usage. Some small roots (such as ttylinux) may not have 'ip' or > 'ifconfig'. > > This patch replaces the use of these commands with usage of > netdevice. The result is that lxc containers do not have to implement > those commands, and lxc in libvirt is only dependent on the netdevice > interface. Requiring fewer tools in the container seems like a very good thing, especially when trying to create a tiny busybox-based container.

> I've tested this patch locally against the ubuntu libvirt version enough > to verify its generally sane. I attempted to build upstream today, but > failed with: > /usr/bin/ld: > ../src/.libs/libvirt_driver_qemu.a(libvirt_driver_qemu_la-qemu_domain.o): > undefined reference to symbol &#39;xmlXPathRegisterNs@(a)LIBXML2_2.4.30 > > Thats probably a local issue only, but I wanted to get this patch up and > see what others thought of it. This is ubuntu bug > https://bugs.launchpad.net/ubuntu/+source/libvirt/+bug/828211 . > > diff --git a/src/lxc/veth.c b/src/lxc/veth.c > index 34cb804..c24df91 100644 > --- a/src/lxc/veth.c > +++ b/src/lxc/veth.c > @@ -12,8 +12,11 @@ > > #include <config.h> > > +#include <linux/sockios.h> > +#include <net/if.h> > #include <string.h> > #include <stdio.h> > +#include <sys/ioctl.h> > #include <sys/types.h> > #include <sys/wait.h> > > @@ -186,41 +189,49 @@ int vethDelete(const char *veth) > * @veth: name of veth device > * @upOrDown: 0 => down, 1 => up > * > - * Enables a veth device using the ifconfig command. A NULL inetAddress > - * will cause it to be left off the command line. > + * Enables a veth device using SIOCSIFFLAGS > * > - * Returns 0 on success or -1 in case of error > + * Returns 0 on success, -1 on failure, with errno set > */ > int vethInterfaceUpOrDown(const char* veth, int upOrDown) > { > - int rc; > - const char *argv[] = {"ifconfig", veth, NULL, NULL}; > - int cmdResult = 0; > + struct ifreq ifr; > + int fd, ret; > > - if (0 == upOrDown) > - argv[2] = "down"; > - else > - argv[2] = "up"; > + if ((fd = socket(PF_PACKET, SOCK_DGRAM, 0)) == -1) > + return(-1); > > - rc = virRun(argv, &cmdResult); > + memset(&ifr, 0, sizeof(struct ifreq)); > > - if (rc != 0 || > - (WIFEXITED(cmdResult) && WEXITSTATUS(cmdResult) != 0)) { > - if (0 == upOrDown) > + if (virStrcpyStatic(ifr.ifr_name, veth) == NULL) { > + errno = EINVAL; > + return -1; > + } > + > + if ((ret = ioctl(fd, SIOCGIFFLAGS, &ifr)) == 0) { > + if (upOrDown) > + ifr.ifr_flags |= IFF_UP; > + else > + ifr.ifr_flags &= ~(IFF_UP | IFF_RUNNING); > + > + ret = ioctl(fd, SIOCSIFFLAGS, &ifr); > + } > + > + close(fd); > + if (ret == -1) > + if (upOrDown == 0) > /* > * Prevent overwriting an error log which may be set > * where an actual failure occurs. > */ > - VIR_DEBUG("Failed to disable '%s' (%d)", > - veth, WEXITSTATUS(cmdResult)); > + VIR_DEBUG("Failed to disable '%s'", veth); > else > vethError(VIR_ERR_INTERNAL_ERROR, > - _("Failed to enable '%s' (%d)"), > - veth, WEXITSTATUS(cmdResult)); > - rc = -1; > - } > + _("Failed to enable '%s'"), veth); > + else > + ret = 0; > > - return rc; > + return(ret); > } > > /** > @@ -279,17 +290,29 @@ int setMacAddr(const char* iface, const char* macaddr) > * @iface: name of device > * @new: new name of @iface > * > - * Changes the name of the given device with the > - * given new name using this command: > - * ip link set @iface name @new > + * Changes the name of the given device. > * > - * Returns 0 on success or -1 in case of error > + * Returns 0 on success, -1 on failure with errno set. > */ > int setInterfaceName(const char* iface, const char* new) > { > - const char *argv[] = { > - "ip", "link", "set", iface, "name", new, NULL > - }; > + struct ifreq ifr; > + int fd = socket(PF_PACKET, SOCK_DGRAM, 0); > > - return virRun(argv, NULL); > + memset(&ifr, 0, sizeof(struct ifreq)); > + > + if (virStrcpyStatic(ifr.ifr_name, iface) == NULL) { > + errno = EINVAL; > + return -1; > + } > + > + if (virStrcpyStatic(ifr.ifr_newname, new) == NULL) { > + errno = EINVAL; > + return -1; > + } > + > + if (ioctl(fd, SIOCSIFNAME, &ifr)) > + return -1; > + > + return 0; > } >