pmbootstrap init: Ask for hostname, default: device name (#1327)

* Save "" (empty string) in the user's config as hostname if the user
  let it default to the name of the device. That way, when the device
  gets changed, the user won't get the old device's name as hostname
  by accident.
* Add a test case

pmb/config/__init__.py

@@ -45,8 +45,8 @@ apk_tools_static_min_version = "2.9.0-r0"
 work_version = "1"
 
 # Only save keys to the config file, which we ask for in 'pmbootstrap init'.
-config_keys = ["ccache_size", "device", "extra_packages", "jobs", "keymap",
-               "nonfree_firmware", "nonfree_userland",
+config_keys = ["ccache_size", "device", "extra_packages", "hostname", "jobs",
+               "keymap", "nonfree_firmware", "nonfree_userland",
                "qemu_native_mesa_driver", "timezone", "ui", "user", "work"]
 
 # Config file/commandline default values
@@ -62,6 +62,7 @@ defaults = {
     "config": os.path.expanduser("~") + "/.config/pmbootstrap.cfg",
     "device": "samsung-i9100",
     "extra_packages": "none",
+    "hostname": "",
     # A higher value is typically desired, but this can lead to VERY long open
     # times on slower devices due to host systems being MUCH faster than the
     # target device: <https://github.com/postmarketOS/pmbootstrap/issues/429>

pmb/config/init.py

@@ -240,6 +240,18 @@ def ask_for_build_options(args, cfg):
     cfg["pmbootstrap"]["ccache_size"] = answer
 
 
+def ask_for_hostname(args, device):
+    while True:
+        ret = pmb.helpers.cli.ask(args, "Device hostname (short form, e.g. 'foo')",
+                                  None, (args.hostname or device), True)
+        if not pmb.helpers.other.validate_hostname(ret):
+            continue
+        # Don't store device name in user's config (gets replaced in install)
+        if ret == device:
+            return ""
+        return ret
+
+
 def frontend(args):
     cfg = pmb.config.load(args)
 
@@ -281,6 +293,9 @@ def frontend(args):
     # Configure timezone info
     cfg["pmbootstrap"]["timezone"] = ask_for_timezone(args)
 
+    # Hostname
+    cfg["pmbootstrap"]["hostname"] = ask_for_hostname(args, device)
+
     # Save config
     pmb.config.save(args, cfg)
 

pmb/helpers/other.py

@@ -16,8 +16,9 @@ GNU General Public License for more details.
 You should have received a copy of the GNU General Public License
 along with pmbootstrap.  If not, see <http://www.gnu.org/licenses/>.
 """
-import os
 import logging
+import os
+import re
 import pmb.chroot
 import pmb.config
 import pmb.helpers.run
@@ -127,3 +128,26 @@ def migrate_work_folder(args):
                        " folder manually ('sudo rm -rf " + args.work +
                        "') and start over with 'pmbootstrap init'. All your"
                        " binary packages will be lost.")
+
+
+def validate_hostname(hostname):
+    """
+    Check whether the string is a valid hostname, according to
+    <http://en.wikipedia.org/wiki/Hostname#Restrictions_on_valid_host_names>
+    """
+    # Check length
+    if len(hostname) > 63:
+        logging.fatal("ERROR: Hostname '" + hostname + "' is too long.")
+        return False
+
+    # Check that it only contains valid chars
+    if not re.match("^[0-9a-z-]*$", hostname):
+        logging.fatal("ERROR: Hostname must only contain letters (a-z),"
+                      " digits (0-9) or minus signs (-)")
+        return False
+
+    # Check that doesn't begin or end with a minus sign
+    if hostname[:1] == "-" or hostname[-1:] == "-":
+        logging.fatal("ERROR: Hostname must not begin or end with a minus sign")
+        return False
+    return True

pmb/install/_install.py

@@ -18,7 +18,9 @@ along with pmbootstrap.  If not, see <http://www.gnu.org/licenses/>.
 """
 import logging
 import os
+import re
 import glob
+import shlex
 
 import pmb.chroot
 import pmb.chroot.apk
@@ -234,6 +236,28 @@ def setup_keymap(args):
         logging.info("NOTE: No valid keymap specified for device")
 
 
+def setup_hostname(args):
+    """
+    Set the hostname and update localhost address in /etc/hosts
+    """
+    # Default to device name
+    hostname = args.hostname
+    if not hostname:
+        hostname = args.device
+
+    if not pmb.helpers.other.validate_hostname(hostname):
+        raise RuntimeError("Hostname '" + hostname + "' is not valid, please"
+                           " run 'pmbootstrap init' to configure it.")
+
+    # Update /etc/hosts
+    suffix = "rootfs_" + args.device
+    pmb.chroot.root(args, ["sh", "-c", "echo " + shlex.quote(hostname) +
+                    " > /etc/hostname"], suffix)
+    regex = ("s/^127\.0\.0\.1.*/127.0.0.1\t" + re.escape(hostname) +
+             " localhost.localdomain localhost/")
+    pmb.chroot.root(args, ["sed", "-i", "-e", regex, "/etc/hosts"], suffix)
+
+
 def install_system_image(args):
     # Partition and fill image/sdcard
     logging.info("*** (3/5) PREPARE INSTALL BLOCKDEVICE ***")
@@ -377,6 +401,9 @@ def install(args):
     # Set timezone
     pmb.chroot.root(args, ["setup-timezone", "-z", args.timezone], suffix)
 
+    # Set the hostname as the device name
+    setup_hostname(args)
+
     if args.android_recovery_zip:
         install_recovery_zip(args)
     else:

test/test_questions.py

@@ -219,3 +219,28 @@ def test_questions_build_options(args, monkeypatch):
     func(args, cfg)
     assert cfg == {"pmbootstrap": {"jobs": "5",
                                    "ccache_size": "2G"}}
+
+
+def test_questions_hostname(args, monkeypatch):
+    func = pmb.config.init.ask_for_hostname
+    device = "test-device"
+
+    # Valid hostname
+    fake_answers(monkeypatch, ["valid"])
+    assert func(args, device) == "valid"
+
+    # Hostname too long ("aaaaa...")
+    fake_answers(monkeypatch, ["a" * 64, "a" * 63])
+    assert func(args, device) == "a" * 63
+
+    # Fail the regex
+    fake_answers(monkeypatch, ["$invalid", "valid"])
+    assert func(args, device) == "valid"
+
+    # Begins or ends with minus
+    fake_answers(monkeypatch, ["-invalid", "invalid-", "valid"])
+    assert func(args, device) == "valid"
+
+    # Device name: empty string
+    fake_answers(monkeypatch, [device])
+    assert func(args, device) == ""