src/debug-generator/debug-generator.c

   1 /* SPDX-License-Identifier: LGPL-2.1-or-later */
   2
   3 #include <unistd.h>
   4
   5 #include "alloc-util.h"
   6 #include "bitfield.h"
   7 #include "creds-util.h"
   8 #include "dropin.h"
   9 #include "errno-util.h"
  10 #include "extract-word.h"
  11 #include "fileio.h"
  12 #include "log.h"
  13 #include "generator.h"
  14 #include "initrd-util.h"
  15 #include "parse-util.h"
  16 #include "path-util.h"
  17 #include "proc-cmdline.h"
  18 #include "recurse-dir.h"
  19 #include "special.h"
  20 #include "string-util.h"
  21 #include "strv.h"
  22 #include "unit-file.h"
  23 #include "unit-name.h"
  24
  25 static const char *arg_dest = NULL;
  26 static char *arg_default_unit = NULL;
  27 static char **arg_mask = NULL;
  28 static char **arg_wants = NULL;
  29 static bool arg_debug_shell = false;
  30 static char *arg_debug_tty = NULL;
  31 static char *arg_default_debug_tty = NULL;
  32 static uint32_t arg_breakpoints = 0;
  33
  34 STATIC_DESTRUCTOR_REGISTER(arg_default_unit, freep);
  35 STATIC_DESTRUCTOR_REGISTER(arg_mask, strv_freep);
  36 STATIC_DESTRUCTOR_REGISTER(arg_wants, strv_freep);
  37 STATIC_DESTRUCTOR_REGISTER(arg_debug_tty, freep);
  38 STATIC_DESTRUCTOR_REGISTER(arg_default_debug_tty, freep);
  39
  40 typedef enum BreakpointType {
  41         BREAKPOINT_PRE_UDEV,
  42         BREAKPOINT_PRE_BASIC,
  43         BREAKPOINT_PRE_SYSROOT_MOUNT,
  44         BREAKPOINT_PRE_SWITCH_ROOT,
  45         _BREAKPOINT_TYPE_MAX,
  46         _BREAKPOINT_TYPE_INVALID = -EINVAL,
  47 } BreakpointType;
  48
  49 typedef enum BreakpointValidity {
  50         BREAKPOINT_DEFAULT   = 1 << 0,
  51         BREAKPOINT_IN_INITRD = 1 << 1,
  52         BREAKPOINT_ON_HOST   = 1 << 2,
  53 } BreakpointValidity;
  54
  55 typedef struct BreakpointInfo {
  56         BreakpointType type;
  57         const char *name;
  58         const char *unit;
  59         BreakpointValidity validity;
  60 } BreakpointInfo;
  61
  62 static const struct BreakpointInfo breakpoint_info_table[_BREAKPOINT_TYPE_MAX] = {
  63         { BREAKPOINT_PRE_UDEV,          "pre-udev",        "breakpoint-pre-udev.service",        BREAKPOINT_IN_INITRD | BREAKPOINT_ON_HOST },
  64         { BREAKPOINT_PRE_BASIC,         "pre-basic",       "breakpoint-pre-basic.service",       BREAKPOINT_IN_INITRD | BREAKPOINT_ON_HOST },
  65         { BREAKPOINT_PRE_SYSROOT_MOUNT, "pre-mount",       "breakpoint-pre-mount.service",       BREAKPOINT_IN_INITRD                      },
  66         { BREAKPOINT_PRE_SWITCH_ROOT,   "pre-switch-root", "breakpoint-pre-switch-root.service", BREAKPOINT_IN_INITRD | BREAKPOINT_DEFAULT },
  67 };
  68
  69 static bool breakpoint_applies(const BreakpointInfo *info, int log_level) {
  70         assert(info);
  71
  72         if (in_initrd() && !FLAGS_SET(info->validity, BREAKPOINT_IN_INITRD))
  73                 log_full(log_level, "Breakpoint '%s' not valid in the initrd, ignoring.", info->name);
  74         else if (!in_initrd() && !FLAGS_SET(info->validity, BREAKPOINT_ON_HOST))
  75                 log_full(log_level, "Breakpoint '%s' not valid on the host, ignoring.", info->name);
  76         else
  77                 return true;
  78
  79         return false;
  80 }
  81
  82 static BreakpointType parse_breakpoint_from_string_one(const char *s) {
  83         assert(s);
  84
  85         FOREACH_ELEMENT(i, breakpoint_info_table)
  86                 if (streq(i->name, s))
  87                         return i->type;
  88
  89         return _BREAKPOINT_TYPE_INVALID;
  90 }
  91
  92 static int parse_breakpoint_from_string(const char *s, uint32_t *ret_breakpoints) {
  93         uint32_t breakpoints = 0;
  94         int r;
  95
  96         assert(ret_breakpoints);
  97
  98         /* Empty value? set default breakpoint */
  99         if (isempty(s)) {
 100                 bool found_default = false;
 101
 102                 FOREACH_ELEMENT(i, breakpoint_info_table)
 103                         if (FLAGS_SET(i->validity, BREAKPOINT_DEFAULT) && breakpoint_applies(i, INT_MAX)) {
 104                                 breakpoints |= 1 << i->type;
 105                                 found_default = true;
 106                                 break;
 107                         }
 108
 109                 if (!found_default)
 110                         log_warning("No default breakpoint defined %s, ignoring.",
 111                                     in_initrd() ? "in the initrd" : "on the host");
 112         } else
 113                 for (;;) {
 114                         _cleanup_free_ char *t = NULL;
 115                         BreakpointType tt;
 116
 117                         r = extract_first_word(&s, &t, ",", EXTRACT_DONT_COALESCE_SEPARATORS);
 118                         if (r < 0)
 119                                 return r;
 120                         if (r == 0)
 121                                 break;
 122
 123                         tt = parse_breakpoint_from_string_one(t);
 124                         if (tt < 0) {
 125                                 log_warning("Invalid breakpoint value '%s', ignoring.", t);
 126                                 continue;
 127                         }
 128
 129                         if (breakpoint_applies(&breakpoint_info_table[tt], LOG_WARNING))
 130                                 breakpoints |= 1 << tt;
 131                 }
 132
 133         *ret_breakpoints = breakpoints;
 134
 135         return 0;
 136 }
 137
 138 static int parse_proc_cmdline_item(const char *key, const char *value, void *data) {
 139         int r;
 140
 141         assert(key);
 142
 143         if (streq(key, "systemd.mask")) {
 144                 char *n;
 145
 146                 if (proc_cmdline_value_missing(key, value))
 147                         return 0;
 148
 149                 r = unit_name_mangle(value, UNIT_NAME_MANGLE_WARN, &n);
 150                 if (r < 0)
 151                         return log_error_errno(r, "Failed to glob unit name: %m");
 152
 153                 if (strv_consume(&arg_mask, n) < 0)
 154                         return log_oom();
 155
 156         } else if (streq(key, "systemd.wants")) {
 157                 char *n;
 158
 159                 if (proc_cmdline_value_missing(key, value))
 160                         return 0;
 161
 162                 r = unit_name_mangle(value, UNIT_NAME_MANGLE_WARN, &n);
 163                 if (r < 0)
 164                         return log_error_errno(r, "Failed to glob unit name: %m");
 165
 166                 if (strv_consume(&arg_wants, n) < 0)
 167                         return log_oom();
 168
 169         } else if (proc_cmdline_key_streq(key, "systemd.debug_shell")) {
 170
 171                 r = value ? parse_boolean(value) : 1;
 172                 arg_debug_shell = r != 0;
 173                 if (r >= 0)
 174                         return 0;
 175
 176                 return free_and_strdup_warn(&arg_debug_tty, skip_dev_prefix(value));
 177
 178         } else if (proc_cmdline_key_streq(key, "systemd.default_debug_tty")) {
 179
 180                 if (proc_cmdline_value_missing(key, value))
 181                         return 0;
 182
 183                 return free_and_strdup_warn(&arg_default_debug_tty, skip_dev_prefix(value));
 184
 185         } else if (streq(key, "systemd.unit")) {
 186
 187                 if (proc_cmdline_value_missing(key, value))
 188                         return 0;
 189
 190                 return free_and_strdup_warn(&arg_default_unit, value);
 191
 192         } else if (streq(key, "systemd.break")) {
 193                 uint32_t breakpoints = 0;
 194
 195                 r = parse_breakpoint_from_string(value, &breakpoints);
 196                 if (r < 0)
 197                         return log_warning_errno(r, "Failed to parse breakpoint value '%s': %m", value);
 198
 199                 arg_breakpoints |= breakpoints;
 200
 201         } else if (!value) {
 202                 const char *target;
 203
 204                 target = runlevel_to_target(key);
 205                 if (target)
 206                         return free_and_strdup_warn(&arg_default_unit, target);
 207         }
 208
 209         return 0;
 210 }
 211
 212 static int generate_mask_symlinks(void) {
 213         int r = 0;
 214
 215         STRV_FOREACH(u, arg_mask) {
 216                 _cleanup_free_ char *p = NULL;
 217
 218                 p = path_join(arg_dest, *u);
 219                 if (!p)
 220                         return log_oom();
 221
 222                 if (symlink("/dev/null", p) < 0)
 223                         RET_GATHER(r, log_error_errno(errno, "Failed to create mask symlink '%s': %m", p));
 224         }
 225
 226         return r;
 227 }
 228
 229 static int generate_wants_symlinks(void) {
 230         int r = 0;
 231
 232         STRV_FOREACH(u, arg_wants) {
 233                 _cleanup_free_ char *f = NULL;
 234                 const char *target;
 235
 236                 /* This should match what do_queue_default_job() in core/main.c does. */
 237                 if (arg_default_unit)
 238                         target = arg_default_unit;
 239                 else if (in_initrd())
 240                         target = SPECIAL_INITRD_TARGET;
 241                 else
 242                         target = SPECIAL_DEFAULT_TARGET;
 243
 244                 f = path_join(SYSTEM_DATA_UNIT_DIR, *u);
 245                 if (!f)
 246                         return log_oom();
 247
 248                 RET_GATHER(r, generator_add_symlink(arg_dest, target, "wants", f));
 249         }
 250
 251         return r;
 252 }
 253
 254 static int install_debug_shell_dropin(void) {
 255         const char *tty = arg_debug_tty ?: arg_default_debug_tty;
 256         int r;
 257
 258         if (!tty || path_equal(tty, skip_dev_prefix(DEBUGTTY)))
 259                 return 0;
 260
 261         r = write_drop_in_format(arg_dest, "debug-shell.service", 50, "tty",
 262                                  "# Automatically generated by systemd-debug-generator\n\n"
 263                                  "[Unit]\n"
 264                                  "Description=Early root shell on /dev/%s FOR DEBUGGING ONLY\n"
 265                                  "ConditionPathExists=\n"
 266                                  "\n[Service]\n"
 267                                  "TTYPath=/dev/%s\n",
 268                                  tty, tty);
 269         if (r < 0)
 270                 return log_warning_errno(r, "Failed to write drop-in for debug-shell.service: %m");
 271
 272         return 1;
 273 }
 274
 275 static int process_unit_credentials(const char *credentials_dir) {
 276         _cleanup_free_ DirectoryEntries *des = NULL;
 277         int r;
 278
 279         assert(credentials_dir);
 280
 281         r = readdir_all_at(AT_FDCWD, credentials_dir, RECURSE_DIR_SORT|RECURSE_DIR_IGNORE_DOT|RECURSE_DIR_ENSURE_TYPE, &des);
 282         if (r < 0)
 283                 return log_error_errno(r, "Failed to enumerate credentials from credentials directory '%s': %m", credentials_dir);
 284
 285         FOREACH_ARRAY(i, des->entries, des->n_entries) {
 286                 struct dirent *de = *i;
 287                 const char *unit, *dropin;
 288
 289                 if (de->d_type != DT_REG)
 290                         continue;
 291
 292                 unit = startswith(de->d_name, "systemd.extra-unit.");
 293                 dropin = startswith(de->d_name, "systemd.unit-dropin.");
 294
 295                 if (!unit && !dropin)
 296                         continue;
 297
 298                 _cleanup_free_ char *d = NULL;
 299
 300                 r = read_credential_with_decryption(de->d_name, (void**) &d, NULL);
 301                 if (r < 0) {
 302                         log_warning_errno(r, "Failed to read credential '%s', ignoring: %m", de->d_name);
 303                         continue;
 304                 }
 305
 306                 if (unit) {
 307                         _cleanup_free_ char *p = NULL;
 308
 309                         if (!unit_name_is_valid(unit, UNIT_NAME_ANY)) {
 310                                 log_warning("Invalid unit name '%s' in credential '%s', ignoring.",
 311                                             unit, de->d_name);
 312                                 continue;
 313                         }
 314
 315                         p = path_join(arg_dest, unit);
 316                         if (!p)
 317                                 return log_oom();
 318
 319                         r = write_string_file(p, d, WRITE_STRING_FILE_CREATE|WRITE_STRING_FILE_ATOMIC|WRITE_STRING_FILE_MKDIR_0755|WRITE_STRING_FILE_LABEL);
 320                         if (r < 0) {
 321                                 log_warning_errno(r, "Failed to write unit file '%s' from credential '%s', ignoring: %m",
 322                                                   unit, de->d_name);
 323                                 continue;
 324                         }
 325
 326                         log_debug("Wrote unit file '%s' from credential '%s'", unit, de->d_name);
 327
 328                 } else if (dropin) {
 329                         _cleanup_free_ char *dropin_unit = NULL;
 330                         const char *tilde, *dropin_name;
 331
 332                         tilde = strchrnul(dropin, '~');
 333                         dropin_unit = strndup(dropin, tilde - dropin);
 334                         if (!dropin_unit)
 335                                 return log_oom();
 336
 337                         if (!unit_name_is_valid(dropin_unit, UNIT_NAME_ANY)) {
 338                                 log_warning("Invalid unit name '%s' in credential '%s', ignoring.",
 339                                             dropin_unit, de->d_name);
 340                                 continue;
 341                         }
 342
 343                         dropin_name = isempty(tilde) ? "50-credential" : tilde + 1;
 344                         if (isempty(dropin_name)) {
 345                                 log_warning("Empty drop-in name for unit '%s' in credential '%s', ignoring.",
 346                                             dropin_unit, de->d_name);
 347                                 continue;
 348                         }
 349
 350                         r = write_drop_in(arg_dest, dropin_unit, /* level = */ UINT_MAX, dropin_name, d);
 351                         if (r < 0) {
 352                                 log_warning_errno(r, "Failed to write drop-in '%s' for unit '%s' from credential '%s', ignoring: %m",
 353                                                   dropin_name, dropin_unit, de->d_name);
 354                                 continue;
 355                         }
 356
 357                         log_debug("Wrote drop-in '%s' for unit '%s' from credential '%s'", dropin_name, dropin_unit, de->d_name);
 358                 } else
 359                         assert_not_reached();
 360         }
 361
 362         return 0;
 363 }
 364
 365 static int run(const char *dest, const char *dest_early, const char *dest_late) {
 366         const char *credentials_dir;
 367         int r;
 368
 369         assert_se(arg_dest = dest_early);
 370
 371         r = proc_cmdline_parse(parse_proc_cmdline_item, NULL, PROC_CMDLINE_RD_STRICT | PROC_CMDLINE_STRIP_RD_PREFIX);
 372         if (r < 0)
 373                 log_warning_errno(r, "Failed to parse kernel command line, ignoring: %m");
 374
 375         if (arg_debug_shell) {
 376                 if (strv_extend(&arg_wants, "debug-shell.service") < 0)
 377                         return log_oom();
 378
 379                 RET_GATHER(r, install_debug_shell_dropin());
 380         }
 381
 382         BIT_FOREACH(i, arg_breakpoints)
 383                 if (strv_extend(&arg_wants, breakpoint_info_table[i].unit) < 0)
 384                         return log_oom();
 385
 386         if (get_credentials_dir(&credentials_dir) >= 0)
 387                 RET_GATHER(r, process_unit_credentials(credentials_dir));
 388
 389         if (get_encrypted_credentials_dir(&credentials_dir) >= 0)
 390                 RET_GATHER(r, process_unit_credentials(credentials_dir));
 391
 392         RET_GATHER(r, generate_mask_symlinks());
 393         RET_GATHER(r, generate_wants_symlinks());
 394
 395         return r;
 396 }
 397
 398 DEFINE_MAIN_GENERATOR_FUNCTION(run);