pyrox.dev
1#! @python3@/bin/python3 -B
2import argparse
3import shutil
4import os
5import sys
6import errno
7import subprocess
8import glob
9import tempfile
10import errno
11import warnings
12import ctypes
13libc = ctypes.CDLL("libc.so.6")
14import re
15import datetime
16import glob
17import os.path
18
19def copy_if_not_exists(source, dest):
20 if not os.path.exists(dest):
21 shutil.copyfile(source, dest)
22
23def system_dir(profile, generation):
24 if profile:
25 return "/nix/var/nix/profiles/system-profiles/%s-%d-link" % (profile, generation)
26 else:
27 return "/nix/var/nix/profiles/system-%d-link" % (generation)
28
29BOOT_ENTRY = """title NixOS{profile}
30version Generation {generation} {description}
31linux {kernel}
32initrd {initrd}
33options {kernel_params}
34"""
35
36def write_loader_conf(profile, generation):
37 with open("@efiSysMountPoint@/loader/loader.conf.tmp", 'w') as f:
38 if "@timeout@" != "":
39 f.write("timeout @timeout@\n")
40 if profile:
41 f.write("default nixos-%s-generation-%d\n" % (profile, generation))
42 else:
43 f.write("default nixos-generation-%d\n" % (generation))
44 if not @editor@:
45 f.write("editor 0\n");
46 f.write("console-mode @consoleMode@\n");
47 os.rename("@efiSysMountPoint@/loader/loader.conf.tmp", "@efiSysMountPoint@/loader/loader.conf")
48
49def profile_path(profile, generation, name):
50 return os.readlink("%s/%s" % (system_dir(profile, generation), name))
51
52def copy_from_profile(profile, generation, name, dry_run=False):
53 store_file_path = profile_path(profile, generation, name)
54 suffix = os.path.basename(store_file_path)
55 store_dir = os.path.basename(os.path.dirname(store_file_path))
56 efi_file_path = "/efi/nixos/%s-%s.efi" % (store_dir, suffix)
57 if not dry_run:
58 copy_if_not_exists(store_file_path, "@efiSysMountPoint@%s" % (efi_file_path))
59 return efi_file_path
60
61def describe_generation(generation_dir):
62 try:
63 with open("%s/nixos-version" % generation_dir) as f:
64 nixos_version = f.read()
65 except IOError:
66 nixos_version = "Unknown"
67
68 kernel_dir = os.path.dirname(os.path.realpath("%s/kernel" % generation_dir))
69 module_dir = glob.glob("%s/lib/modules/*" % kernel_dir)[0]
70 kernel_version = os.path.basename(module_dir)
71
72 build_time = int(os.path.getctime(generation_dir))
73 build_date = datetime.datetime.fromtimestamp(build_time).strftime('%F')
74
75 description = "NixOS {}, Linux Kernel {}, Built on {}".format(
76 nixos_version, kernel_version, build_date
77 )
78
79 return description
80
81def write_entry(profile, generation, machine_id):
82 kernel = copy_from_profile(profile, generation, "kernel")
83 initrd = copy_from_profile(profile, generation, "initrd")
84 try:
85 append_initrd_secrets = profile_path(profile, generation, "append-initrd-secrets")
86 subprocess.check_call([append_initrd_secrets, "@efiSysMountPoint@%s" % (initrd)])
87 except FileNotFoundError:
88 pass
89 if profile:
90 entry_file = "@efiSysMountPoint@/loader/entries/nixos-%s-generation-%d.conf" % (profile, generation)
91 else:
92 entry_file = "@efiSysMountPoint@/loader/entries/nixos-generation-%d.conf" % (generation)
93 generation_dir = os.readlink(system_dir(profile, generation))
94 tmp_path = "%s.tmp" % (entry_file)
95 kernel_params = "systemConfig=%s init=%s/init " % (generation_dir, generation_dir)
96
97 with open("%s/kernel-params" % (generation_dir)) as params_file:
98 kernel_params = kernel_params + params_file.read()
99 with open(tmp_path, 'w') as f:
100 f.write(BOOT_ENTRY.format(profile=" [" + profile + "]" if profile else "",
101 generation=generation,
102 kernel=kernel,
103 initrd=initrd,
104 kernel_params=kernel_params,
105 description=describe_generation(generation_dir)))
106 if machine_id is not None:
107 f.write("machine-id %s\n" % machine_id)
108 os.rename(tmp_path, entry_file)
109
110def mkdir_p(path):
111 try:
112 os.makedirs(path)
113 except OSError as e:
114 if e.errno != errno.EEXIST or not os.path.isdir(path):
115 raise
116
117def get_generations(profile=None):
118 gen_list = subprocess.check_output([
119 "@nix@/bin/nix-env",
120 "--list-generations",
121 "-p",
122 "/nix/var/nix/profiles/%s" % ("system-profiles/" + profile if profile else "system"),
123 "--option", "build-users-group", ""],
124 universal_newlines=True)
125 gen_lines = gen_list.split('\n')
126 gen_lines.pop()
127 return [ (profile, int(line.split()[0])) for line in gen_lines ]
128
129def remove_old_entries(gens):
130 rex_profile = re.compile("^@efiSysMountPoint@/loader/entries/nixos-(.*)-generation-.*\.conf$")
131 rex_generation = re.compile("^@efiSysMountPoint@/loader/entries/nixos.*-generation-(.*)\.conf$")
132 known_paths = []
133 for gen in gens:
134 known_paths.append(copy_from_profile(*gen, "kernel", True))
135 known_paths.append(copy_from_profile(*gen, "initrd", True))
136 for path in glob.iglob("@efiSysMountPoint@/loader/entries/nixos*-generation-[1-9]*.conf"):
137 try:
138 if rex_profile.match(path):
139 prof = rex_profile.sub(r"\1", path)
140 else:
141 prof = "system"
142 gen = int(rex_generation.sub(r"\1", path))
143 if not (prof, gen) in gens:
144 os.unlink(path)
145 except ValueError:
146 pass
147 for path in glob.iglob("@efiSysMountPoint@/efi/nixos/*"):
148 if not path in known_paths:
149 os.unlink(path)
150
151def get_profiles():
152 if os.path.isdir("/nix/var/nix/profiles/system-profiles/"):
153 return [x
154 for x in os.listdir("/nix/var/nix/profiles/system-profiles/")
155 if not x.endswith("-link")]
156 else:
157 return []
158
159def main():
160 parser = argparse.ArgumentParser(description='Update NixOS-related systemd-boot files')
161 parser.add_argument('default_config', metavar='DEFAULT-CONFIG', help='The default NixOS config to boot')
162 args = parser.parse_args()
163
164 try:
165 with open("/etc/machine-id") as machine_file:
166 machine_id = machine_file.readlines()[0]
167 except IOError as e:
168 if e.errno != errno.ENOENT:
169 raise
170 # Since systemd version 232 a machine ID is required and it might not
171 # be there on newly installed systems, so let's generate one so that
172 # bootctl can find it and we can also pass it to write_entry() later.
173 cmd = ["@systemd@/bin/systemd-machine-id-setup", "--print"]
174 machine_id = subprocess.check_output(cmd).rstrip()
175
176 if os.getenv("NIXOS_INSTALL_GRUB") == "1":
177 warnings.warn("NIXOS_INSTALL_GRUB env var deprecated, use NIXOS_INSTALL_BOOTLOADER", DeprecationWarning)
178 os.environ["NIXOS_INSTALL_BOOTLOADER"] = "1"
179
180 if os.getenv("NIXOS_INSTALL_BOOTLOADER") == "1":
181 # bootctl uses fopen() with modes "wxe" and fails if the file exists.
182 if os.path.exists("@efiSysMountPoint@/loader/loader.conf"):
183 os.unlink("@efiSysMountPoint@/loader/loader.conf")
184
185 if "@canTouchEfiVariables@" == "1":
186 subprocess.check_call(["@systemd@/bin/bootctl", "--path=@efiSysMountPoint@", "install"])
187 else:
188 subprocess.check_call(["@systemd@/bin/bootctl", "--path=@efiSysMountPoint@", "--no-variables", "install"])
189
190 mkdir_p("@efiSysMountPoint@/efi/nixos")
191 mkdir_p("@efiSysMountPoint@/loader/entries")
192
193 gens = get_generations()
194 for profile in get_profiles():
195 gens += get_generations(profile)
196 remove_old_entries(gens)
197 for gen in gens:
198 write_entry(*gen, machine_id)
199 if os.readlink(system_dir(*gen)) == args.default_config:
200 write_loader_conf(*gen)
201
202 # Since fat32 provides little recovery facilities after a crash,
203 # it can leave the system in an unbootable state, when a crash/outage
204 # happens shortly after an update. To decrease the likelihood of this
205 # event sync the efi filesystem after each update.
206 rc = libc.syncfs(os.open("@efiSysMountPoint@", os.O_RDONLY))
207 if rc != 0:
208 print("could not sync @efiSysMountPoint@: {}".format(os.strerror(rc)), file=sys.stderr)
209
210if __name__ == '__main__':
211 main()