1 /*@ S-nail - a mail user agent derived from Berkeley Mail.
2 *@ Signal related stuff as well as NotYetDead functions.
4 * Copyright (c) 2000-2004 Gunnar Ritter, Freiburg i. Br., Germany.
5 * Copyright (c) 2012 - 2016 Steffen (Daode) Nurpmeso <steffen@sdaoden.eu>.
8 * Copyright (c) 1980, 1993
9 * The Regents of the University of California. All rights reserved.
11 * Redistribution and use in source and binary forms, with or without
12 * modification, are permitted provided that the following conditions
14 * 1. Redistributions of source code must retain the above copyright
15 * notice, this list of conditions and the following disclaimer.
16 * 2. Redistributions in binary form must reproduce the above copyright
17 * notice, this list of conditions and the following disclaimer in the
18 * documentation and/or other materials provided with the distribution.
19 * 3. Neither the name of the University nor the names of its contributors
20 * may be used to endorse or promote products derived from this software
21 * without specific prior written permission.
23 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
26 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
38 #ifndef HAVE_AMALGAMATION
43 * TODO At the beginning of November 2015 -- for v14.9 -- i've tried for one
44 * TODO and a half week to convert this codebase to SysV style signal handling,
45 * TODO meaning no SA_RESTART and EINTR in a lot of places and error reporting
46 * TODO up the chain. I failed miserably, not only because S/MIME / SSL but
47 * TODO also because of general frustration. Directly after v14.9 i will strip
48 * TODO ANYTHING off the codebase (socket stuff etc.) and keep only the very
49 * TODO core, doing namespace and type cleanup and convert this core to a clean
50 * TODO approach, from which i plan to start this thing anew.
51 * TODO For now i introduced the n_sigman, yet another hack, to be used in a
53 * TODO The real solution:
54 * TODO - No SA_RESTART. Just like for my C++ library: encapsulate EINTR in
55 * TODO userspace at the systemcall (I/O rewrite: drop stdio), normal
56 * TODO interface auto-restarts, special _intr() series return EINTR.
57 * TODO Do n_sigman_poll()/peek()/whatever whenever desired for the former,
58 * TODO report errors up the call chain, have places where operations can be
59 * TODO "properly" aborted.
60 * TODO - We save the initial signal settings upon program startup.
61 * TODO - We register our sigman handlers once, at program startup.
62 * TODO Maximally, and most likely only due to lack of atomic CAS, ignore
63 * TODO or block some signals temporarily. Best if not.
64 * TODO The signal handlers only set a flag. Block all signals for handler
65 * TODO execution, like this we are safe to "set the first signal was x".
66 * TODO - In interactive context, ignore SIGTERM.
67 * TODO I.e., see the POSIX standard for what a shell does.
68 * TODO - In non-interactive context, don't know anything about job control!?!
69 * TODO - Place child processes in their own process group. Restore the signal
70 * TODO mask back to the saved original one for them, before exec.
71 * TODO - Except for job control related (<-> interactive) ignore any signals
72 * TODO while we are "behind" a child that occupies the terminal. For those,
73 * TODO perform proper terminal attribute handling. For childs that don't
74 * TODO occupy the terminal we "are the shell" and should therefore manage
75 * TODO them accordingly, including termination request as necessary.
76 * TODO And if we have a worker in a pipeline, we need to manage it and deal
77 * TODO with it properly, WITHOUT temporary signal overwrites.
78 * TODO - No more jumps.
79 * TODO - (When sockets will be reintroduced, non-blocking.)
80 * TODO - (When SSL is reintroduced, memory BIO. It MAY be necessary to
81 * TODO temporarily block signals during a few SSL functions? Read SSL docu!
82 * TODO But i prefer blocking since it's a single syscall, not temporary
83 * TODO SA_RESTART setting, since that has to be done for every signal.)
95 /* {hold,rele}_all_sigs() */
96 static size_t _alls_depth
;
97 static sigset_t _alls_nset
, _alls_oset
;
99 /* {hold,rele}_sigs() */
100 static size_t _hold_sigdepth
;
101 static sigset_t _hold_nset
, _hold_oset
;
103 /* NYD, memory pool debug */
105 static ui32_t _nyd_curr
, _nyd_level
;
106 static struct nyd_info _nyd_infos
[NYD_CALLS_MAX
];
111 static void _nyd_print(int fd
, struct nyd_info
*nip
);
116 _nyd_print(int fd
, struct nyd_info
*nip
)
119 union {int i
; size_t z
;} u
;
121 u
.i
= snprintf(buf
, sizeof buf
,
122 "%c [%2" PRIu32
"] %.25s (%.16s:%" PRIu32
")\n",
123 "=><"[(nip
->ni_chirp_line
>> 29) & 0x3], nip
->ni_level
, nip
->ni_fun
,
124 nip
->ni_file
, (nip
->ni_chirp_line
& 0x1FFFFFFFu
));
127 if (u
.z
> sizeof buf
)
128 u
.z
= sizeof buf
- 1; /* (Skip \0) */
138 kill(getpid(), signo
);
143 safe_signal(int signum
, sighandler_type handler
)
145 struct sigaction nact
, oact
;
149 nact
.sa_handler
= handler
;
150 sigemptyset(&nact
.sa_mask
);
151 nact
.sa_flags
= SA_RESTART
;
152 rv
= (sigaction(signum
, &nact
, &oact
) != 0) ? SIG_ERR
: oact
.sa_handler
;
158 n_signal(int signo
, n_sighdl_t hdl
){
159 struct sigaction nact
, oact
;
162 nact
.sa_handler
= hdl
;
163 sigemptyset(&nact
.sa_mask
);
165 hdl
= (sigaction(signo
, &nact
, &oact
) != 0) ? SIG_ERR
: oact
.sa_handler
;
174 if (_alls_depth
++ == 0) {
175 sigfillset(&_alls_nset
);
176 sigdelset(&_alls_nset
, SIGABRT
);
178 sigdelset(&_alls_nset
, SIGBUS
);
180 sigdelset(&_alls_nset
, SIGCHLD
);
181 sigdelset(&_alls_nset
, SIGFPE
);
182 sigdelset(&_alls_nset
, SIGILL
);
183 sigdelset(&_alls_nset
, SIGKILL
);
184 sigdelset(&_alls_nset
, SIGSEGV
);
185 sigdelset(&_alls_nset
, SIGSTOP
);
186 sigprocmask(SIG_BLOCK
, &_alls_nset
, &_alls_oset
);
195 if (--_alls_depth
== 0)
196 sigprocmask(SIG_SETMASK
, &_alls_oset
, (sigset_t
*)NULL
);
204 if (_hold_sigdepth
++ == 0) {
205 sigemptyset(&_hold_nset
);
206 sigaddset(&_hold_nset
, SIGHUP
);
207 sigaddset(&_hold_nset
, SIGINT
);
208 sigaddset(&_hold_nset
, SIGQUIT
);
209 sigprocmask(SIG_BLOCK
, &_hold_nset
, &_hold_oset
);
218 if (--_hold_sigdepth
== 0)
219 sigprocmask(SIG_SETMASK
, &_hold_oset
, NULL
);
223 /* TODO This is temporary gracyness */
224 static struct n_sigman
*n__sigman
;
225 static void n__sigman_hdl(int signo
);
227 n__sigman_hdl(int signo
){
228 NYD_X
; /* Signal handler */
229 n__sigman
->sm_signo
= signo
;
230 siglongjmp(n__sigman
->sm_jump
, 1);
234 n__sigman_enter(struct n_sigman
*self
, int flags
){
235 /* TODO no error checking when installing sighdls */
240 self
->sm_flags
= (enum n_sigman_flags
)flags
;
242 self
->sm_outer
= n__sigman
;
243 if(flags
& n_SIGMAN_HUP
)
244 self
->sm_ohup
= safe_signal(SIGHUP
, &n__sigman_hdl
);
245 if(flags
& n_SIGMAN_INT
)
246 self
->sm_oint
= safe_signal(SIGINT
, &n__sigman_hdl
);
247 if(flags
& n_SIGMAN_QUIT
)
248 self
->sm_oquit
= safe_signal(SIGQUIT
, &n__sigman_hdl
);
249 if(flags
& n_SIGMAN_PIPE
)
250 self
->sm_opipe
= safe_signal(SIGPIPE
, &n__sigman_hdl
);
254 flags
= self
->sm_flags
;
256 /* Just in case of a race (signal while holding and ignoring? really?) */
257 if(!(flags
& n__SIGMAN_PING
)){
258 if(flags
& n_SIGMAN_HUP
)
259 safe_signal(SIGHUP
, SIG_IGN
);
260 if(flags
& n_SIGMAN_INT
)
261 safe_signal(SIGINT
, SIG_IGN
);
262 if(flags
& n_SIGMAN_QUIT
)
263 safe_signal(SIGQUIT
, SIG_IGN
);
264 if(flags
& n_SIGMAN_PIPE
)
265 safe_signal(SIGPIPE
, SIG_IGN
);
268 /* The signal mask has been restored, but of course rele_sigs() has
269 * already been called: account for restoration due to jump */
278 n_sigman_cleanup_ping(struct n_sigman
*self
){
289 safe_signal(SIGHUP
, SIG_IGN
);
291 safe_signal(SIGINT
, SIG_IGN
);
292 if(f
& n_SIGMAN_QUIT
)
293 safe_signal(SIGQUIT
, SIG_IGN
);
294 if(f
& n_SIGMAN_PIPE
)
295 safe_signal(SIGPIPE
, SIG_IGN
);
302 n_sigman_leave(struct n_sigman
*self
,
303 enum n_sigman_flags reraise_flags
){
309 n__sigman
= self
->sm_outer
;
313 safe_signal(SIGHUP
, self
->sm_ohup
);
315 safe_signal(SIGINT
, self
->sm_oint
);
316 if(f
& n_SIGMAN_QUIT
)
317 safe_signal(SIGQUIT
, self
->sm_oquit
);
318 if(f
& n_SIGMAN_PIPE
)
319 safe_signal(SIGPIPE
, self
->sm_opipe
);
324 switch(self
->sm_signo
){
326 if((reraise_flags
& n_SIGMAN_PIPE
) ||
327 ((reraise_flags
& n_SIGMAN_NTTYOUT_PIPE
) &&
328 !(options
& OPT_TTYOUT
)))
332 if(reraise_flags
& n_SIGMAN_HUP
)
336 if(reraise_flags
& n_SIGMAN_INT
)
340 if(reraise_flags
& n_SIGMAN_QUIT
)
352 sigaddset(&cset
, sig
);
353 sigprocmask(SIG_UNBLOCK
, &cset
, NULL
);
368 n_sigman_consume(void){
375 _nyd_chirp(ui8_t act
, char const *file
, ui32_t line
, char const *fun
)
377 struct nyd_info
*nip
= _nyd_infos
;
379 if (_nyd_curr
!= n_NELEM(_nyd_infos
))
385 nip
->ni_chirp_line
= ((ui32_t
)(act
& 0x3) << 29) | (line
& 0x1FFFFFFFu
);
386 nip
->ni_level
= ((act
== 0) ? _nyd_level
387 : (act
== 1) ? ++_nyd_level
: _nyd_level
--);
391 _nyd_oncrash(int signo
)
393 char pathbuf
[PATH_MAX
], s2ibuf
[32], *cp
;
394 struct sigaction xact
;
396 struct nyd_info
*nip
;
401 n_LCTA(sizeof("./") -1 + sizeof(VAL_UAGENT
) -1 + sizeof(".dat") < PATH_MAX
,
402 "System limits too low for fixed-size buffer operation");
404 xact
.sa_handler
= SIG_DFL
;
405 sigemptyset(&xact
.sa_mask
);
407 sigaction(signo
, &xact
, NULL
);
409 i
= strlen(tmpdir
= ok_vlook(TMPDIR
));
410 fnl
= sizeof(VAL_UAGENT
) -1;
412 if (i
+ 1 + fnl
+ 1 + sizeof(".dat") > sizeof(pathbuf
)) {
413 (cp
= pathbuf
)[0] = '.';
416 memcpy(cp
= pathbuf
, tmpdir
, i
);
417 cp
[i
++] = '/'; /* xxx pathsep */
418 memcpy(cp
+= i
, VAL_UAGENT
, fnl
);
420 memcpy(cp
+= fnl
, ".dat", sizeof(".dat"));
421 fnl
= i
+ sizeof(".dat") -1;
423 if ((fd
= open(pathbuf
, O_WRONLY
| O_CREAT
| O_EXCL
, 0666)) == -1)
427 # define _X(X) (X), sizeof(X) -1
428 write(fd
, _X("\n\nNYD: program dying due to signal "));
430 cp
= s2ibuf
+ sizeof(s2ibuf
) -1;
434 *--cp
= "0123456789"[i
% 10];
437 write(fd
, cp
, PTR2SIZE((s2ibuf
+ sizeof(s2ibuf
) -1) - cp
));
439 write(fd
, _X(":\n"));
441 if (_nyd_infos
[n_NELEM(_nyd_infos
) - 1].ni_file
!= NULL
)
442 for (i
= _nyd_curr
, nip
= _nyd_infos
+ i
; i
< n_NELEM(_nyd_infos
); ++i
)
443 _nyd_print(fd
, nip
++);
444 for (i
= 0, nip
= _nyd_infos
; i
< _nyd_curr
; ++i
)
445 _nyd_print(fd
, nip
++);
447 write(fd
, _X("----------\nCome up to the lab and see what's on the slab\n"));
449 if (fd
!= STDERR_FILENO
) {
450 write(STDERR_FILENO
, _X("Crash NYD listing written to "));
451 write(STDERR_FILENO
, pathbuf
, fnl
);
452 write(STDERR_FILENO
, _X("\n"));
459 sigaddset(&xset
, signo
);
460 sigprocmask(SIG_UNBLOCK
, &xset
, NULL
);
465 #endif /* HAVE_NYD */