From e4ded6ce7fa7db246d7e13d17abdbadeb7ec8cfe Mon Sep 17 00:00:00 2001 From: Matthew Heon Date: Tue, 25 Sep 2018 11:35:16 -0400 Subject: Switch to using libnetwork's resolvconf package Libnetwork provides a well-tested package for generating resolv.conf from the host's that has some features our current implementation does not. Swap to using their code and remove our built-in implementation. Signed-off-by: Matthew Heon --- libpod/container_internal.go | 102 +++++++++++++------------------------------ 1 file changed, 31 insertions(+), 71 deletions(-) (limited to 'libpod') diff --git a/libpod/container_internal.go b/libpod/container_internal.go index c925f070b..9a2777efc 100644 --- a/libpod/container_internal.go +++ b/libpod/container_internal.go @@ -17,11 +17,12 @@ import ( "github.com/containers/libpod/pkg/hooks/exec" "github.com/containers/libpod/pkg/rootless" "github.com/containers/libpod/pkg/secrets" - "github.com/containers/libpod/pkg/util" "github.com/containers/storage" "github.com/containers/storage/pkg/archive" "github.com/containers/storage/pkg/chrootarchive" "github.com/containers/storage/pkg/mount" + "github.com/docker/libnetwork/netutils" + "github.com/docker/libnetwork/resolvconf" spec "github.com/opencontainers/runtime-spec/specs-go" "github.com/opencontainers/runtime-tools/generate" "github.com/opencontainers/selinux/go-selinux/label" @@ -1017,12 +1018,6 @@ func (c *Container) writeStringToRundir(destFile, output string) (string, error) return filepath.Join(c.state.DestinationRunDir, destFile), nil } -type resolvConf struct { - nameServers []string - searchDomains []string - options []string -} - // generateResolvConf generates a containers resolv.conf func (c *Container) generateResolvConf() (string, error) { // Determine the endpoint for resolv.conf in case it is a symlink @@ -1030,86 +1025,51 @@ func (c *Container) generateResolvConf() (string, error) { if err != nil { return "", err } - orig, err := ioutil.ReadFile(resolvPath) + + contents, err := ioutil.ReadFile(resolvPath) if err != nil { return "", errors.Wrapf(err, "unable to read %s", resolvPath) } - if len(c.config.DNSServer) == 0 && len(c.config.DNSSearch) == 0 && len(c.config.DNSOption) == 0 { - return c.writeStringToRundir("resolv.conf", fmt.Sprintf("%s", orig)) - } - - // Read and organize the hosts /etc/resolv.conf - resolv := createResolv(string(orig[:])) - // Populate the resolv struct with user's dns search domains - if len(c.config.DNSSearch) > 0 { - resolv.searchDomains = nil - // The . character means the user doesnt want any search domains in the container - if !util.StringInSlice(".", c.config.DNSSearch) { - resolv.searchDomains = append(resolv.searchDomains, c.Config().DNSSearch...) - } + // Process the file to remove localhost nameservers + // TODO: set ipv6 enable bool more sanely + resolv, err := resolvconf.FilterResolvDNS(contents, true) + if err != nil { + return "", errors.Wrapf(err, "error parsing host resolv.conf") } - // Populate the resolv struct with user's dns servers + // Make a new resolv.conf + nameservers := resolvconf.GetNameservers(resolv.Content, netutils.IP) if len(c.config.DNSServer) > 0 { - resolv.nameServers = nil - for _, i := range c.config.DNSServer { - resolv.nameServers = append(resolv.nameServers, i.String()) + // We store DNS servers as net.IP, so need to convert to string + nameservers = []string{} + for _, server := range c.config.DNSServer { + nameservers = append(nameservers, server.String()) } } - // Populate the resolve struct with the users dns options - if len(c.config.DNSOption) > 0 { - resolv.options = nil - resolv.options = append(resolv.options, c.Config().DNSOption...) + search := resolvconf.GetSearchDomains(resolv.Content) + if len(c.config.DNSSearch) > 0 { + search = c.config.DNSSearch } - return c.writeStringToRundir("resolv.conf", resolv.ToString()) -} -// createResolv creates a resolv struct from an input string -func createResolv(input string) resolvConf { - var resolv resolvConf - for _, line := range strings.Split(input, "\n") { - if strings.HasPrefix(line, "search") { - fields := strings.Fields(line) - if len(fields) < 2 { - logrus.Debugf("invalid resolv.conf line %s", line) - continue - } - resolv.searchDomains = append(resolv.searchDomains, fields[1:]...) - } else if strings.HasPrefix(line, "nameserver") { - fields := strings.Fields(line) - if len(fields) < 2 { - logrus.Debugf("invalid resolv.conf line %s", line) - continue - } - resolv.nameServers = append(resolv.nameServers, fields[1]) - } else if strings.HasPrefix(line, "options") { - fields := strings.Fields(line) - if len(fields) < 2 { - logrus.Debugf("invalid resolv.conf line %s", line) - continue - } - resolv.options = append(resolv.options, fields[1:]...) - } + options := resolvconf.GetOptions(resolv.Content) + if len(c.config.DNSOption) > 0 { + options = c.config.DNSOption } - return resolv -} -//ToString returns a resolv struct in the form of a resolv.conf -func (r resolvConf) ToString() string { - var result string - // Populate the output string with search domains - result += fmt.Sprintf("search %s\n", strings.Join(r.searchDomains, " ")) - // Populate the output string with name servers - for _, i := range r.nameServers { - result += fmt.Sprintf("nameserver %s\n", i) + destPath := filepath.Join(c.state.RunDir, "resolv.conf") + + if err := os.Remove(destPath); err != nil && !os.IsNotExist(err) { + return "", errors.Wrapf(err, "error removing resolv.conf for container %s", c.ID()) } - // Populate the output string with dns options - for _, i := range r.options { - result += fmt.Sprintf("options %s\n", i) + + // Build resolv.conf + if _, err = resolvconf.Build(destPath, nameservers, search, options); err != nil { + return "", errors.Wrapf(err, "error building resolv.conf for container %s") } - return result + + return destPath, nil } // generateHosts creates a containers hosts file -- cgit v1.2.3-54-g00ecf