summaryrefslogtreecommitdiff
path: root/src/init/s6-linux-init-maker.c
blob: 33197eefb4dbb849b3ccea20b8c22c0e00033e09 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
/* ISC license. */

#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <errno.h>
#include <pwd.h>
#include <skalibs/config.h>
#include <skalibs/uint64.h>
#include <skalibs/uint.h>
#include <skalibs/gidstuff.h>
#include <skalibs/bytestr.h>
#include <skalibs/allreadwrite.h>
#include <skalibs/buffer.h>
#include <skalibs/strerr2.h>
#include <skalibs/stralloc.h>
#include <skalibs/djbunix.h>
#include <skalibs/sgetopt.h>
#include <skalibs/skamisc.h>
#include <execline/config.h>
#include <s6/config.h>

#define USAGE "s6-linux-init-maker [ -c basedir ] [ -l tmpfsdir ] [ -b execline_bindir ] [ -u log_user ] [ -g early_getty_cmd ] [ -2 stage2_script ] [ -r ] [ -3 stage3_script ] [ -p initial_path ] [ -m initial_umask ] [ -t timestamp_style ] [ -d dev_style ] [ -e initial_envvar ... ] dir"
#define dieusage() strerr_dieusage(100, USAGE)
#define dienomem() strerr_diefu1sys(111, "stralloc_catb") ;

#define BANNER "*\n* init created by s6-linux-init-maker\n* see http://skarnet.org/software/s6-linux-init/\n*\n"

#define CRASH_SCRIPT \
"#!" EXECLINE_EXTBINPREFIX "execlineb -P\n\n" \
"redirfd -r 0 /dev/console\n" \
"redirfd -w 1 /dev/console\n" \
"fdmove -c 2 1\n" \
"foreground { s6-echo -- " \
"\"s6-svscan crashed. Dropping to an interactive shell.\" }\n" \
"/bin/sh -i\n"

static char const *slashrun = "/run" ;
static char const *robase = "/etc/s6-linux-init" ;
static char const *init_script = "/etc/rc.init" ;
static char const *shutdown_script = "/etc/rc.shutdown" ;
static char const *bindir = "/bin" ;
static char const *initial_path = SKALIBS_DEFAULTPATH ;
static char const *early_getty = 0 ;
static uid_t uncaught_logs_uid = 65534 ;
static gid_t uncaught_logs_gid = 65534 ;
static unsigned int initial_umask = 022 ;
static unsigned int timestamp_style = 1 ;
static unsigned int slashdev_style = 2 ;
static int redirect_stage2 = 0 ;

typedef int writetobuf_func_t (buffer *) ;
typedef writetobuf_func_t *writetobuf_func_t_ref ;

static int early_getty_script (buffer *b)
{
  if (buffer_puts(b, "#!" EXECLINE_EXTBINPREFIX "execlineb -P\n\n") < 0
   || buffer_puts(b, early_getty) < 0
   || buffer_put(b, "\n", 1) < 0)
    return 0 ;
  return 1 ;
}

static int s6_svscan_log_script (buffer *b)
{
  unsigned int sabase = satmp.len ;
  char fmt[UINT64_FMT] ;
  if (buffer_puts(b,
    "#!" EXECLINE_EXTBINPREFIX "execlineb -P\n\n"
    "redirfd -rnb 0 fifo\n"
    "s6-applyuidgid -u ") < 0
   || buffer_put(b, fmt, uint64_fmt(fmt, uncaught_logs_uid)) < 0
   || buffer_puts(b, " -g ") < 0
   || buffer_put(b, fmt, gid_fmt(fmt, uncaught_logs_gid)) < 0
   || buffer_puts(b, " --\ns6-log -bp -- ") < 0
   || buffer_puts(b, timestamp_style & 1 ? "t " : "") < 0
   || buffer_puts(b, timestamp_style & 2 ? "T " : "") < 0) return 0 ;
  if (!string_quote(&satmp, slashrun, str_len(slashrun))) return 0 ;
  if (buffer_put(b, satmp.s + sabase, satmp.len - sabase) < 0)
  {
    satmp.len = sabase ;
    return 0 ;
  }
  satmp.len = sabase ;
  if (buffer_puts(b, "/uncaught-logs\n") < 0) return 0 ;
  return 1 ;
}

static int finish_script (buffer *b)
{
  unsigned int sabase = satmp.len ;
  if (buffer_puts(b, 
    "#!" EXECLINE_EXTBINPREFIX "execlineb -S0\n\n"
    "cd /\nredirfd -w 2 /dev/console\nfdmove -c 1 2\nwait { }\n") < 0
   || !string_quote(&satmp, shutdown_script, str_len(shutdown_script))) return 0 ;
  if (buffer_put(b, satmp.s + sabase, satmp.len - sabase) < 0)
  {
    satmp.len = sabase ;
    return 0 ;
  }
  satmp.len = sabase ;
  if (buffer_puts(b, " ${@}\n") < 0) return 0 ;
  return 1 ;
}

static void cleanup (char const *base)
{
  int e = errno ;
  rm_rf(base) ;
  errno = e ;
}

static void auto_dir (char const *base, char const *dir, uid_t uid, gid_t gid, unsigned int mode)
{
  unsigned int clen = str_len(base) ;
  unsigned int dlen = str_len(dir) ;
  char fn[clen + dlen + 2] ;
  byte_copy(fn, clen, base) ;
  fn[clen] = dlen ? '/' : 0 ;
  byte_copy(fn + clen + 1, dlen + 1, dir) ;
  if (mkdir(fn, mode) < 0
   || ((uid || gid) && (chown(fn, uid, gid) < 0 || chmod(fn, mode) < 0)))
  {
    cleanup(base) ;
    strerr_diefu2sys(111, "mkdir ", fn) ;
  }
}

static void auto_file (char const *base, char const *file, char const *s, unsigned int n, int executable)
{
  unsigned int clen = str_len(base) ;
  unsigned int flen = str_len(file) ;
  char fn[clen + flen + 2] ;
  byte_copy(fn, clen, base) ;
  fn[clen] = '/' ;
  byte_copy(fn + clen + 1, flen + 1, file) ;
  if (!openwritenclose_unsafe(fn, s, n)
   || (executable && chmod(fn, 0755) < 0))
  {
    cleanup(base) ;
    strerr_diefu2sys(111, "write to ", fn) ;
  }
}

static void auto_fifo (char const *base, char const *fifo)
{
  unsigned int baselen = str_len(base) ;
  unsigned int fifolen = str_len(fifo) ;
  char fn[baselen + fifolen + 2] ;
  byte_copy(fn, baselen, base) ;
  fn[baselen] = '/' ;
  byte_copy(fn + baselen + 1, fifolen + 1, fifo) ;
  if (mkfifo(fn, 0600) < 0)
  {
    cleanup(base) ;
    strerr_diefu2sys(111, "mkfifo ", fn) ;
  }
}

static void auto_script (char const *base, char const *file, writetobuf_func_t_ref scriptf)
{
  char buf[4096] ;
  buffer b ;
  int fd ;
  unsigned int baselen = str_len(base) ;
  unsigned int filelen = str_len(file) ;
  char fn[baselen + filelen + 2] ;
  byte_copy(fn, baselen, base) ;
  fn[baselen] = '/' ;
  byte_copy(fn + baselen + 1, filelen + 1, file) ;
  fd = open_trunc(fn) ;
  if (fd < 0 || ndelay_off(fd) < 0 || fchmod(fd, 0755) < 0)
  {
    cleanup(base) ;
    strerr_diefu3sys(111, "open ", fn, " for script writing") ;
  }
  buffer_init(&b, &fd_writesv, fd, buf, 4096) ;
  if (!(*scriptf)(&b) || !buffer_flush(&b))
  {
    cleanup(base) ;
    strerr_diefu2sys(111, "write to ", fn) ;
  }
  close(fd) ;
}

static void make_image (char const *base)
{
  auto_dir(base, "run-image", 0, 0, 0755) ;
  auto_dir(base, "run-image/uncaught-logs", uncaught_logs_uid, uncaught_logs_gid, 02700) ;
  auto_dir(base, "run-image/service", 0, 0, 0755) ;
  auto_dir(base, "run-image/service/.s6-svscan", 0, 0, 0755) ;
  auto_file(base, "run-image/service/.s6-svscan/crash", CRASH_SCRIPT, sizeof(CRASH_SCRIPT) - 1, 1) ;
  auto_script(base, "run-image/service/.s6-svscan/finish", &finish_script) ;
  auto_dir(base, "run-image/service/s6-svscan-log", 0, 0, 0755) ;
  auto_fifo(base, "run-image/service/s6-svscan-log/fifo") ;
  auto_script(base, "run-image/service/s6-svscan-log/run", &s6_svscan_log_script) ;
  if (early_getty)
  {
    auto_dir(base, "run-image/service/early-getty", 0, 0, 0755) ;
    auto_script(base, "run-image/service/early-getty/run", &early_getty_script) ;
  }
}

static void make_env (char const *base, char const *modif, unsigned int modiflen)
{
  auto_dir(base, "env", 0, 0, 0755) ;
  while (modiflen)
  {
    unsigned int len = str_len(modif) ;
    unsigned int pos = byte_chr(modif, len, '=') ;
    char fn[5 + pos] ;
    byte_copy(fn, 4, "env/") ;
    byte_copy(fn + 4, pos, modif) ;
    fn[4 + pos] = 0 ;
    
    if (pos + 1 < len) auto_file(base, fn, modif + pos + 1, len - pos - 1, 0) ;
    else if (pos + 1 == len) auto_file(base, fn, "\n", 1, 0) ;
    else auto_file(base, fn, "", 0, 0) ;
    modif += len+1 ; modiflen -= len+1 ;
  }
}

static int make_init_script (buffer *b)
{
  unsigned int sabase = satmp.len, pos, pos2 ;
  char fmt[UINT_OFMT] ;
  if (buffer_puts(b, "#!") < 0
   || buffer_puts(b, bindir) < 0
   || buffer_puts(b, "/execlineb -P\n\n") < 0
   || buffer_puts(b, bindir) < 0
   || buffer_puts(b, "/export PATH ") < 0
   || !string_quote(&satmp, initial_path, str_len(initial_path))) return 0 ;
  if (buffer_put(b, satmp.s + sabase, satmp.len - sabase) < 0) goto err ;
  satmp.len = sabase ;
  if (buffer_put(b, "\n", 1) < 0
   || buffer_puts(b, bindir) < 0
   || buffer_puts(b, "/cd /\numask 0") < 0
   || buffer_put(b, fmt, uint_ofmt(fmt, initial_umask)) < 0
   || buffer_puts(b, "\nif { s6-echo -- ") < 0
   || !string_quote(&satmp, BANNER, sizeof(BANNER) - 1) < 0) return 0 ;
  if (buffer_put(b, satmp.s, satmp.len) < 0) goto err ;
  satmp.len = sabase ;
  if (buffer_puts(b, " }\nif { s6-mount -nwt tmpfs -o mode=0755 tmpfs ") < 0
   || !string_quote(&satmp, slashrun, str_len(slashrun))) return 0 ;
  pos = satmp.len ;
  if (buffer_put(b, satmp.s + sabase, pos - sabase) < 0
   || buffer_puts(b, " }\nif { s6-hiercopy ") < 0
   || !string_quote(&satmp, robase, str_len(robase))) return 0 ;
  pos2 = satmp.len ;
  if (buffer_put(b, satmp.s + pos, pos2 - pos) < 0
   || buffer_puts(b, "/run-image ") < 0
   || buffer_put(b, satmp.s + sabase, pos - sabase) < 0
   || buffer_puts(b, " }\n") < 0) goto err ;
  if (slashdev_style == 1)
  {
    if (buffer_puts(b, "if { s6-mount -nt devtmpfs dev /dev }\n") < 0) goto err ;
  }
  if (buffer_puts(b, "redirfd -r 0 /dev/null\ns6-envdir -I -- ") < 0
   || buffer_put(b, satmp.s + pos, pos2 - pos) < 0
   || buffer_puts(b, "/env\nbackground\n{\n  s6-setsid --\n  ") < 0) goto err ;
  if (redirect_stage2)
  {
    if (buffer_puts(b, "redirfd -w 2 ") < 0
     || buffer_put(b, satmp.s + sabase, pos - sabase) < 0
     || buffer_puts(b, "/service/s6-svscan-log/fifo\n  fdmove -c 1 2\n  ") < 0) goto err ;
  }
  else
  {
    if (buffer_puts(b, "redirfd -w 3 ") < 0
     || buffer_put(b, satmp.s + sabase, pos - sabase) < 0
     || buffer_puts(b, "/service/s6-svscan-log/fifo\n  fdclose 3\n  ") < 0) goto err ;
  }
  if (!string_quote(&satmp, init_script, str_len(init_script))
   || buffer_put(b, satmp.s + pos2, satmp.len - pos2) < 0
   || buffer_puts(b, "\n}\nunexport !\nredirfd -wnb 1 ") < 0
   || buffer_put(b, satmp.s + sabase, pos - sabase) < 0
   || buffer_puts(b, "/service/s6-svscan-log/fifo\nfdmove -c 2 1\ncd ") < 0
   || buffer_put(b, satmp.s + sabase, pos - sabase) < 0
   || buffer_puts(b, "/service\ns6-svscan -t0\n") < 0) goto err ;
  return 1 ;
 err:
  satmp.len = sabase ;
  return 0 ;
}

int main (int argc, char const *const *argv)
{
  char const *catchall_user = "nobody" ;
  stralloc modif = STRALLOC_ZERO ;
  PROG = "s6-linux-init-maker" ;
  {
    subgetopt_t l = SUBGETOPT_ZERO ;
    for (;;)
    {
      register int opt = subgetopt_r(argc, argv, "c:l:b:u:g:2:r3:p:m:t:d:e:", &l) ;
      if (opt == -1) break ;
      switch (opt)
      {
        case 'c' : robase = l.arg ; break ;
        case 'l' : slashrun = l.arg ; break ;
        case 'b' : bindir = l.arg ; break ;
        case 'u' : catchall_user = l.arg ; break ;
        case 'g' : early_getty = l.arg ; break ;
        case '2' : init_script = l.arg ; break ;
        case 'r' : redirect_stage2 = 1 ; break ;
        case '3' : shutdown_script = l.arg ; break ;
        case 'p' : initial_path = l.arg ; break ;
        case 'm' : if (!uint0_oscan(l.arg, &initial_umask)) dieusage() ; break ;
        case 't' : if (!uint0_scan(l.arg, &timestamp_style)) dieusage() ; break ;
        case 'd' : if (!uint0_scan(l.arg, &slashdev_style)) dieusage() ; break ;
        case 'e' : if (!stralloc_catb(&modif, l.arg, str_len(l.arg) + 1)) dienomem() ; break ;
        default : dieusage() ;
      }
    }
    argc -= l.ind ; argv += l.ind ;
  }
  if (!argc) dieusage() ;

  if (robase[0] != '/')
    strerr_dief3x(100, "base directory ", robase, " is not absolute") ;
  if (slashrun[0] != '/')
    strerr_dief3x(100, "tmpfs directory ", slashrun, " is not absolute") ;
  if (bindir[0] != '/')
    strerr_dief3x(100, "initial location for binaries ", bindir, " is not absolute") ;
  if (init_script[0] != '/')
    strerr_dief3x(100, "stage 2 script location ", init_script, " is not absolute") ;
  if (shutdown_script[0] != '/')
    strerr_dief3x(100, "stage 3 script location ", shutdown_script, " is not absolute") ;
  if (timestamp_style > 3)
    strerr_dief1x(100, "-t timestamp_style must be 0, 1, 2 or 3") ;
  if (slashdev_style > 2)
    strerr_dief1x(100, "-d dev_style must be 0, 1 or 2") ;


  {
    struct passwd *pw = getpwnam(catchall_user) ;
    if (!pw)
    {
      if (errno)
        strerr_diefu2sys(111, "getpwnam for ", catchall_user) ;
      else
        strerr_dief3x(100, "getpwnam for ", catchall_user, ": no such user") ;
    }
    uncaught_logs_uid = pw->pw_uid ;
    uncaught_logs_gid = pw->pw_gid ;
  }

  if (mkdir(argv[0], 0755) < 0)
    strerr_diefu2sys(111, "mkdir ", argv[0]) ;

  make_env(argv[0], modif.s, modif.len) ;
  stralloc_free(&modif) ;
  make_image(argv[0]) ;
  if (!make_init_script(buffer_1) || !buffer_flush(buffer_1))
    strerr_diefu1sys(111, "write to stdout") ;
  return 0 ;
}