Preserve existing network configuration files during install (#461550)

The suggestion for this patch came from OLPC (or someone with an
@laptop.org email address).  The user was doing a kickstart install
and adding a local yum repo that provided an RPM of site-specific
configuration files, including ifcfg-DEVICE files.  This package
would get installed just fine, but then anaconda drives over the
configuration files after package installation.

If we see any configuration file on the target system during
installation, skip over it and don't write a new one.  This
should handle upgrades and kickstart install types like OLPC was
describing.

1 files changed, 90 insertions, 77 deletions

diff --git a/network.py b/network.py
index 45dc40880..7becba3f5 100644
--- a/network.py
+++ b/network.py
@@ -529,6 +529,11 @@ class Network:
         # /etc/sysconfig/network-scripts/ifcfg-*
         for dev in self.netdevices.values():
             device = dev.get('DEVICE')
+
+            cfgfile = "%s/ifcfg-%s" % (netscripts, device,)
+            if os.path.isfile(cfgfile):
+                continue
+
             bootproto = dev.get('BOOTPROTO').lower()
             ipv6addr = dev.get('IPV6ADDR').lower()
             ipv6prefix = dev.get('IPV6PREFIX').lower()
@@ -600,6 +605,10 @@ class Network:
             # XXX: is this necessary with NetworkManager?
             # handle the keys* files if we have those
             if dev.get("KEY"):
+                cfgfile = "%s/keys-%s" % (netscripts, device,)
+                if os.path.isfile(cfgfile):
+                    continue
+
                 newkey = "%s/keys-%s.new" % (netscripts, device,)
                 f = open(newkey, "w")
                 f.write("KEY=%s\n" % (dev.get('KEY'),))
@@ -610,78 +619,80 @@ class Network:
                 shutil.move(newkey, destkey)
 
         # /etc/sysconfig/network
-        newnetwork = "%s.new" % (destnetwork,)
+        if not os.path.isfile(destnetwork):
+            newnetwork = "%s.new" % (destnetwork,)
 
-        f = open(newnetwork, "w")
-        f.write("NETWORKING=yes\n")
-        f.write("HOSTNAME=")
+            f = open(newnetwork, "w")
+            f.write("NETWORKING=yes\n")
+            f.write("HOSTNAME=")
 
-        # use instclass hostname if set(kickstart) to override
-        if self.hostname:
-            f.write(self.hostname + "\n")
-        else:
-            f.write("localhost.localdomain\n")
+            # use instclass hostname if set(kickstart) to override
+            if self.hostname:
+                f.write(self.hostname + "\n")
+            else:
+                f.write("localhost.localdomain\n")
 
-        if dev.get('GATEWAY'):
-            f.write("GATEWAY=%s\n" % (dev.get('GATEWAY'),))
+            if dev.get('GATEWAY'):
+                f.write("GATEWAY=%s\n" % (dev.get('GATEWAY'),))
 
-        if dev.get('IPV6_DEFAULTGW'):
-            f.write("IPV6_DEFAULTGW=%s\n" % (dev.get('IPV6_DEFAULTGW'),))
+            if dev.get('IPV6_DEFAULTGW'):
+                f.write("IPV6_DEFAULTGW=%s\n" % (dev.get('IPV6_DEFAULTGW'),))
 
-        f.close()
-        shutil.move(newnetwork, destnetwork)
+            f.close()
+            shutil.move(newnetwork, destnetwork)
 
         # /etc/hosts
-        f = open(instPath + "/etc/hosts", "w")
-
-        log.info("self.hostname = %s", self.hostname)
-
-        # IP address
-        ip = self.lookupHostname()
-        if ip in [ "127.0.0.1", "::1" ]:
-            ip = None
-
-        # fqdn and hostname
-        if "." in self.hostname:
-            fqdn = self.hostname
-            hostname = self.hostname.split('.', 1)[0]
-        else:
-            fqdn = socket.getfqdn(self.hostname)
-            hostname = self.hostname
-
-        if fqdn in [ "localhost.localdomain", "localhost",
-                     "localhost6.localdomain6", "localhost6", hostname ] \
-                     or "." not in fqdn:
-            fqdn = None
-
-        # domainname
-        if fqdn:
-            domainname = fqdn.split('.', 1)[1]
-            if domainname in [ "localdomain", "localdomain6" ]:
-                domainname = None
-        else:
-            domainname = None
-
-        localline = "localhost.localdomain localhost"
-        if not ip or not fqdn:
-            # There is no ip or no fqdn, tie it to 127.0.0.1.
+        if not os.path.isfile(instPath + "/etc/hosts"):
+            f = open(instPath + "/etc/hosts", "w")
+
+            log.info("self.hostname = %s", self.hostname)
+
+            # IP address
+            ip = self.lookupHostname()
+            if ip in [ "127.0.0.1", "::1" ]:
+                ip = None
+
+            # fqdn and hostname
+            if "." in self.hostname:
+                fqdn = self.hostname
+                hostname = self.hostname.split('.', 1)[0]
+            else:
+                fqdn = socket.getfqdn(self.hostname)
+                hostname = self.hostname
+
+            if fqdn in [ "localhost.localdomain", "localhost",
+                         "localhost6.localdomain6", "localhost6", hostname ] \
+                         or "." not in fqdn:
+                fqdn = None
+
+            # domainname
             if fqdn:
-                # add fqdn to 127.0.0.1
-                localline += " " + fqdn
-            if hostname and hostname != "localhost":
-                # add short hostname to 127.0.0.1
-                localline += " " + hostname
-
-        f.write("# Do not remove the following line, or various programs\n")
-        f.write("# that require network functionality will fail.\n")
-        f.write("127.0.0.1\t\t" + localline + "\n")
-        f.write("::1\t\tlocalhost6.localdomain6 localhost6\n")
+                domainname = fqdn.split('.', 1)[1]
+                if domainname in [ "localdomain", "localdomain6" ]:
+                    domainname = None
+            else:
+                domainname = None
 
-        if ip and fqdn:
-            # Add an extra entry for ip, fqdn and hostname
-            f.write("%s\t\t%s %s\n" % (ip, fqdn, hostname))
+            localline = "localhost.localdomain localhost"
+            if not ip or not fqdn:
+                # There is no ip or no fqdn, tie it to 127.0.0.1.
+                if fqdn:
+                    # add fqdn to 127.0.0.1
+                    localline += " " + fqdn
+                if hostname and hostname != "localhost":
+                    # add short hostname to 127.0.0.1
+                    localline += " " + hostname
+
+            f.write("# Do not remove the following line, or various programs\n")
+            f.write("# that require network functionality will fail.\n")
+            f.write("127.0.0.1\t\t" + localline + "\n")
+            f.write("::1\t\tlocalhost6.localdomain6 localhost6\n")
+
+            if ip and fqdn:
+                # Add an extra entry for ip, fqdn and hostname
+                f.write("%s\t\t%s %s\n" % (ip, fqdn, hostname))
 
-        f.close()
+            f.close()
 
         # If the hostname was not looked up, but typed in by the user,
         # domain might not be computed, so do it now.
@@ -690,30 +701,32 @@ class Network:
                 self.domains = [domainname]
 
         # /etc/resolv.conf
-        if os.path.isfile('/etc/resolv.conf') and instPath != '':
-            destresolv = "%s/etc/resolv.conf" % (instPath,)
-            shutil.copy('/etc/resolv.conf', destresolv)
-        elif (self.domains != ['localdomain'] and self.domains) or \
-            self.hasNameServers(dev.info):
-            resolv = "%s/etc/resolv.conf" % (instPath,)
+        if not os.path.isfile(instPath + '/etc/resolv.conf'):
+            if os.path.isfile('/etc/resolv.conf') and instPath != '':
+                destresolv = "%s/etc/resolv.conf" % (instPath,)
+                shutil.copy('/etc/resolv.conf', destresolv)
+            elif (self.domains != ['localdomain'] and self.domains) or \
+                self.hasNameServers(dev.info):
+                resolv = "%s/etc/resolv.conf" % (instPath,)
 
-            f = open(resolv, "w")
+                f = open(resolv, "w")
 
-            if self.domains != ['localdomain'] and self.domains:
-                f.write("search %s\n" % (string.joinfields(self.domains, ' '),))
+                if self.domains != ['localdomain'] and self.domains:
+                    f.write("search %s\n" % (string.joinfields(self.domains, ' '),))
 
-            for key in dev.info.keys():
-                if key.upper().startswith('DNS'):
-                    f.write("nameserver %s\n" % (dev.get(key),))
+                for key in dev.info.keys():
+                    if key.upper().startswith('DNS'):
+                        f.write("nameserver %s\n" % (dev.get(key),))
 
-            f.close()
+                f.close()
 
         # /etc/udev/rules.d/70-persistent-net.rules
-        if not instPath == '':
+        rules = instPath + "/etc/udev/rules.d/70-persistent-net.rules"
+        if (not instPath) and (not os.path.isfile(rules)):
             if not os.path.isdir("%s/etc/udev/rules.d" %(instPath,)):
                 iutil.mkdirChain("%s/etc/udev/rules.d" %(instPath,))
 
-            f = open(instPath + "/etc/udev/rules.d/70-persistent-net.rules", "w")
+            f = open(rules, "w")
             f.write("""
 # This file was automatically generated by the /lib/udev/write_net_rules
 # program run by the persistent-net-generator.rules rules file.