5 * Copyright (C)1996-1997,1999-2001,2003 Ian Jackson
7 * This is free software; you can redistribute it and/or modify it
8 * under the terms of the GNU General Public License as published by
9 * the Free Software Foundation; either version 2 of the License, or
10 * (at your option) any later version.
12 * This program is distributed in the hope that it will be useful, but
13 * WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 * General Public License for more details.
17 * You should have received a copy of the GNU General Public License
18 * along with userv; if not, write to the Free Software
19 * Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
23 * Here too, we do some horrible asynchronous stuff with signals.
25 * The following objects &c. are used in signal handlers and so
26 * must be protected by calls to blocksignals if they are used in
31 * The following objects are used in the main program unprotected
32 * and so must not be used in signal handlers:
37 * The following objects/functions are not modified/called after the
38 * asynchronicity starts:
44 * results of argument parsing
46 * systemerror, swfile, fdsetup[].catpid and fdsetup[].killed are used
47 * for communication between the main thread and the signal handlers.
49 * All the signal handlers save errno so that is OK too.
66 #include <sys/types.h>
68 #include <sys/socket.h>
70 #include <sys/resource.h>
78 enum fdmodifiervalues {
92 struct fdmodifierinfo {
100 const char *filename; /* non-null iff this fd has been specified */
101 int copyfd; /* fd to copy, -1 unless mods & fdm_fd */
102 int mods, oflags, pipefd, killed; /* 0,0,-1,0 unless otherwise set */
103 pid_t catpid; /* -1 indicates no cat process */
106 enum signalsexitspecials { se_number=-100, se_numbernocore, se_highbit, se_stdout };
107 enum overridetypes { ot_none, ot_string, ot_file, ot_builtin };
109 struct constkeyvaluepair { const char *key, *value; };
111 /* Variables from command-line arguments */
112 static const char *serviceuser;
113 static uid_t serviceuid;
114 static struct fdsetupstate *fdsetup;
115 static int fdsetupsize;
116 static struct constkeyvaluepair *defvararray;
117 static int defvaravail, defvarused;
118 static unsigned long timeout;
119 static int signalsexit=254;
120 static int sigpipeok, hidecwd;
121 static int overridetype= ot_none;
122 static const char *overridevalue, *spoofuser=0;
124 /* Other state variables */
125 static FILE *srfile, *swfile;
127 static uid_t myuid, spoofuid;
128 static gid_t mygid, spoofgid, *gidarray;
130 static struct opening_msg opening_mbuf;
131 static const char *loginname;
133 static size_t cwdbufsize;
135 static int ovused, systemerror, socketfd;
137 static void blocksignals(int how) {
139 static const char blockerrmsg[]= "userv: failed to [un]block signals: ";
143 sigaddset(&set,SIGCHLD);
144 sigaddset(&set,SIGALRM);
145 if (sigprocmask(how,&set,0)) {
146 str= strerror(errno);
147 write(2,blockerrmsg,sizeof(blockerrmsg)-1);
148 write(2,str,strlen(str));
154 /* Functions which may be called either from signal handlers or from
155 * the main thread. They block signals in case they are on the main
156 * thread, and may only use signal handler objects. None of them
157 * return. If they did they'd have to restore the signal mask.
160 static void NONRETURNPRINTFFORMAT(1,2) miscerror(const char *fmt, ...) {
163 blocksignals(SIG_BLOCK);
165 fprintf(stderr,"userv: failure: ");
166 vfprintf(stderr,fmt,al);
167 fprintf(stderr,"\n");
171 static void NONRETURNPRINTFFORMAT(1,2) fsyscallerror(const char *fmt, ...) {
176 blocksignals(SIG_BLOCK);
178 fprintf(stderr,"userv: system call failure: ");
179 vfprintf(stderr,fmt,al);
180 fprintf(stderr,": %s\n",strerror(e));
184 void syscallerror(const char *what) {
185 fsyscallerror("%s",what);
188 static void NONRETURNING protoreaderror(FILE *file, const char *where) {
192 blocksignals(SIG_BLOCK);
194 fprintf(stderr,"userv: failure: read error %s: %s\n",where,strerror(e));
197 fprintf(stderr,"userv: internal failure: EOF from server %s\n",where);
202 static void NONRETURNPRINTFFORMAT(1,2) protoerror(const char *fmt, ...) {
205 blocksignals(SIG_BLOCK);
207 fprintf(stderr,"userv: internal failure: protocol error: ");
208 vfprintf(stderr,fmt,al);
209 fprintf(stderr,"\n");
214 * General-purpose functions; these do nothing special about signals,
215 * except that they can call error-handlers which may block them
216 * to print error messages.
219 static void xfread(void *p, size_t sz, FILE *file) {
221 nr= working_fread(p,sz,file);
222 if (nr != sz) protoreaderror(file,"in data");
225 static void xfwrite(const void *p, size_t sz, FILE *file) {
227 nr= fwrite(p,1,sz,file); if (nr == sz) return;
228 syscallerror("writing to server");
231 static void xfflush(FILE *file) {
232 if (fflush(file)) syscallerror("flush server socket");
235 /* Functions which may be called only from the main thread. These may
236 * use main-thread objects and must block signals before using signal
241 static void priv_suspend(void) { }
242 static void priv_resume(void) { }
243 static void priv_permanentlyrevokesuspended(void) { }
245 static void priv_suspend(void) {
246 if (setreuid(0,myuid) != 0) syscallerror("suspend root setreuid(0,myuid)");
248 static void priv_resume(void) {
249 if (setreuid(myuid,0) != 0) syscallerror("resume root setreuid(myuid,0)");
251 static void priv_permanentlyrevokesuspended(void) {
252 if (setreuid(myuid,myuid) != 0) syscallerror("revoke root setreuid(myuid,myuid)");
253 if (setreuid(myuid,myuid) != 0) syscallerror("rerevoke root setreuid(myuid,myuid)");
255 if (!setreuid(myuid,0)) miscerror("revoked root but setreuid(0,0) succeeded !");
256 if (errno != EPERM) syscallerror("revoked and setreuid(myuid,0) unexpected error");
261 static void checkmagic(unsigned long was, unsigned long should, const char *when) {
263 protoerror("magic number %s was %08lx, expected %08lx",when,was,should);
266 static void getprogress(struct progress_msg *progress_r, FILE *file) {
271 xfread(progress_r,sizeof(struct progress_msg),file);
272 checkmagic(progress_r->magic,PROGRESS_MAGIC,"in progress message");
273 switch (progress_r->type) {
275 blocksignals(SIG_BLOCK);
276 fputs("userv: uservd reports that service failed\n",stderr);
279 blocksignals(SIG_BLOCK);
280 fputs("uservd: ",stderr);
281 if (progress_r->data.errmsg.messagelen>MAX_ERRMSG_STRING)
282 protoerror("stderr message length %d is far too long",
283 progress_r->data.errmsg.messagelen);
284 for (i=0; i<progress_r->data.errmsg.messagelen; i++) {
285 c= working_getc(file);
286 if (c==EOF) protoreaderror(file,"in error message");
287 if (ISCHAR(isprint,c)) putc(c,stderr);
288 else fprintf(stderr,"\\x%02x",(unsigned char)c);
291 if (ferror(stderr)) syscallerror("printing error message");
292 xfread(&ul,sizeof(ul),file);
293 checkmagic(ul,PROGRESS_ERRMSG_END_MAGIC,"after error message");
294 blocksignals(SIG_UNBLOCK);
303 * Functions which are called only during setup, before
304 * the signal asynchronicity starts. They can do anything they like.
307 /* This includes xmalloc and xrealloc from both.c */
309 static void xfwritestring(const char *s, FILE *file) {
312 assert(l<=MAX_GENERAL_STRING);
313 xfwrite(&l,sizeof(l),file);
314 xfwrite(s,sizeof(*s)*l,file);
317 static void xfwritefds(int modifier, int expected, FILE *file) {
320 for (i=0, fdcount=0; i<fdsetupsize; i++) {
321 if (!(fdsetup[i].filename && (fdsetup[i].mods & modifier)))
323 xfwrite(&i,sizeof(int),file); fdcount++;
325 assert(fdcount == expected);
328 /* Functions which may be called from signal handlers. These
329 * may use signal-handler objects. The main program may only
330 * call them with signals blocked, and they may not use any
331 * main-thread objects.
334 static void disconnect(void) /* DOES return, unlike in daemon */ {
335 struct event_msg event_mbuf;
339 memset(&event_mbuf,0,sizeof(event_mbuf));
340 event_mbuf.magic= EVENT_MAGIC;
341 event_mbuf.type= et_disconnect;
342 r= fwrite(&event_mbuf,1,sizeof(event_mbuf),swfile);
343 if ((r != sizeof(event_mbuf) || fflush(swfile)) && errno != EPIPE)
344 syscallerror("write to server when disconnecting");
349 static void sighandler_alrm(int ignored) /* DOES return, unlike in daemon */ {
352 fputs("userv: timeout\n",stderr);
357 static void sighandler_chld(int ignored) /* DOES return, unlike in daemon */ {
358 struct event_msg event_mbuf;
360 int status, fd, r, es;
364 child= wait3(&status,WNOHANG,0);
365 if (child == 0 || (child == -1 && errno == ECHILD)) break;
366 if (child == -1) syscallerror("wait for child process (in sigchld handler)");
367 for (fd=0; fd<fdsetupsize && fdsetup[fd].catpid != child; fd++);
368 if (fd>=fdsetupsize) continue; /* perhaps the caller gave us children */
369 if ((WIFEXITED(status) && WEXITSTATUS(status)==0) ||
370 (WIFSIGNALED(status) && WTERMSIG(status)==SIGPIPE) ||
371 (fdsetup[fd].killed && WIFSIGNALED(status) && WTERMSIG(status)==SIGKILL)) {
372 if (swfile && fdsetup[fd].mods & fdm_read) {
373 memset(&event_mbuf,0,sizeof(event_mbuf));
374 event_mbuf.magic= EVENT_MAGIC;
375 event_mbuf.type= et_closereadfd;
376 event_mbuf.data.closereadfd.fd= fd;
377 r= fwrite(&event_mbuf,1,sizeof(event_mbuf),swfile);
378 if (r != sizeof(event_mbuf) || fflush(swfile))
379 if (errno != EPIPE) syscallerror("inform service of closed read fd");
382 if (WIFEXITED(status))
383 fprintf(stderr,"userv: cat for fd %d exited with error exit status %d\n",
384 fd,WEXITSTATUS(status));
385 else if (WIFSIGNALED(status))
386 if (WCOREDUMP(status))
387 fprintf(stderr,"userv: cat for fd %d dumped core due to signal %s (%d)\n",
388 fd,strsignal(WTERMSIG(status)),WTERMSIG(status));
390 fprintf(stderr,"userv: cat for fd %d terminated by signal %s (%d)\n",
391 fd,strsignal(WTERMSIG(status)),WTERMSIG(status));
393 fprintf(stderr,"userv: cat for fd %d gave unknown wait status %d\n",
397 fdsetup[fd].catpid= -1;
403 * Argument parsing. These functions which are called only during
404 * setup, before the signal asynchronicity starts.
409 typedef void optionfunction(const struct optioninfo*, const char *value, char *key);
414 int values; /* 0: no value; 1: single value; 2: key and value */
418 static void usage(FILE *stream) {
420 "usage: userv <options> [--] <service-user> <service-name> [<argument> ...]\n"
421 "usage: userv <options> -B|--builtin [--] <builtin-service> [<info-argument> ...]\n"
422 "options: -f|--file <fd>[<fdmodifiers>]=<filename>\n"
423 " -D|--defvar <name>=<value>\n"
424 " -t|--timeout <seconds>\n"
425 " -S|--signals <status>|number|number-nocore|highbit|stdout\n"
426 " -w|--fdwait <fd>=wait|nowait|close\n"
427 " -P|--sigpipe -H|--hidecwd -h|--help|--version --copyright\n"
428 " --override <configuration-data> } available only\n"
429 " --override-file <filename> } to root\n"
430 " --spoof-user <username> } or same user\n"
431 "fdmodifiers: read write overwrite trunc[ate]\n"
432 "(separate with commas) append sync excl[usive] creat[e] fd\n"
433 "userv -B 'X' ... is same as userv --override 'execute-builtin X' - 'X' ...\n"
434 " for help, type `userv -B help'; remember to quote multi-word X\n"
435 "userv and uservd version " VERSION VEREXT ".\n"
436 "Copyright (C)1996-2003,2006 Ian Jackson; copyright (C)2000 Ben Harris.\n"
437 "there is NO WARRANTY; type `userv --copyright' for details.\n",
439 syscallerror("write usage message");
442 static void NONRETURNPRINTFFORMAT(1,2) usageerror(const char *fmt, ...) {
445 fputs("userv: ",stderr);
446 vfprintf(stderr,fmt,al);
447 fputs("\n\n",stderr);
452 static const struct fdmodifierinfo fdmodifierinfos[]= {
456 { "write", fdm_write,
459 { "overwrite", fdm_write|fdm_create|fdm_truncate,
460 fdm_read|fdm_fd|fdm_exclusive,
461 O_WRONLY|O_CREAT|O_TRUNC },
462 { "create", fdm_write|fdm_create,
465 { "creat", fdm_write|fdm_create,
468 { "exclusive", fdm_write|fdm_create|fdm_exclusive,
469 fdm_read|fdm_fd|fdm_truncate,
470 O_WRONLY|O_CREAT|O_EXCL },
471 { "excl", fdm_write|fdm_create|fdm_exclusive,
472 fdm_read|fdm_fd|fdm_truncate,
473 O_WRONLY|O_CREAT|O_EXCL },
474 { "truncate", fdm_write|fdm_truncate,
475 fdm_read|fdm_fd|fdm_exclusive,
476 O_WRONLY|O_CREAT|O_EXCL },
477 { "trunc", fdm_write|fdm_truncate,
478 fdm_read|fdm_fd|fdm_exclusive,
479 O_WRONLY|O_CREAT|O_EXCL },
480 { "append", fdm_write|fdm_append,
482 O_WRONLY|O_CREAT|O_APPEND },
483 { "sync", fdm_write|fdm_sync,
485 O_WRONLY|O_CREAT|O_SYNC },
487 fdm_nowait|fdm_close,
489 { "nowait", fdm_nowait,
492 { "close", fdm_close,
496 fdm_create|fdm_exclusive|fdm_truncate|fdm_append|fdm_sync,
501 static void addfdmodifier(int fd, const char *key, size_t key_len) {
502 const struct fdmodifierinfo *fdmip;
505 for (fdmip= fdmodifierinfos;
507 !(strlen(fdmip->string) == key_len &&
508 !memcmp(fdmip->string,key,key_len));
510 if (!fdmip->string) usageerror("unknown fdmodifer `%.*s' for fd %d",
511 (int)key_len,key,fd);
512 if (fdmip->conflicts & fdsetup[fd].mods)
513 usageerror("fdmodifier `%.*s' conflicts with another for fd %d",
514 (int)key_len,key,fd);
515 fdsetup[fd].mods |= fdmip->implies;
516 fdsetup[fd].oflags |= fdmip->oflags;
519 static void addfdmodifier_fixed(int fd, const char *key) {
520 addfdmodifier(fd, key, strlen(key));
523 static int fdstdnumber(const char *string, const char **delim_r) {
524 #define FN(v,s) do{ \
525 if (!memcmp(string,s,sizeof(s)-1)) { \
526 *delim_r= string+sizeof(s)-1; \
538 static int strtofd(const char *string,
539 const char **mods_r /* 0: no modifiers, must go to end */,
546 fd= fdstdnumber(string,&mods);
548 if (*mods && *mods != ',')
549 usageerror("%s, when it is `stdin', `stdout' or `stderr',"
550 " must be delimited with a comma from any following"
551 " modifiers - `%s' is not permitted",
557 ul= strtoul(string,&delim_v,10);
558 if (errno || delim_v == string || ul > INT_MAX)
559 usageerror("%s must be must be numeric file descriptor"
560 " or `stdin', `stdout' or `stderr'"
561 " - `%s' is not recognized",
573 usageerror("%s must be must be only file descriptor"
574 " - trailing portion or modifiers `%s' not permitted",
577 if (fd > MAX_ALLOW_FD)
578 usageerror("%s file descriptor specified (%d)"
579 " is larger than maximum allowed (%d)",
580 what, fd, MAX_ALLOW_FD);
585 static void of_file(const struct optioninfo *oip, const char *value, char *key) {
586 unsigned long fd, copyfd;
590 const char *mods, *delim;
592 fd= strtofd(key,&mods,"first part of argument to -f or --file");
594 if (fd >= fdsetupsize) {
595 oldarraysize= fdsetupsize;
596 fdsetupsize+=2; fdsetupsize<<=1;
597 fdsetup= xrealloc(fdsetup,sizeof(struct fdsetupstate)*fdsetupsize);
598 while (oldarraysize < fdsetupsize) {
599 fdsetup[oldarraysize].filename= 0;
600 fdsetup[oldarraysize].pipefd= -1;
601 fdsetup[oldarraysize].copyfd= -1;
602 fdsetup[oldarraysize].mods= 0;
603 fdsetup[oldarraysize].oflags= 0;
604 fdsetup[oldarraysize].catpid= -1;
605 fdsetup[oldarraysize].killed= 0;
606 fdsetup[oldarraysize].filename= 0;
610 fdsetup[fd].filename= value;
611 fdsetup[fd].oflags= 0;
613 fdsetup[fd].copyfd= -1;
614 while (mods && *mods) {
615 delim= strchr(mods,',');
616 mod_len= delim ? delim-mods : strlen(mods);
617 addfdmodifier(fd,mods,mod_len);
618 mods= delim ? delim+1 : 0;
620 if (!(fdsetup[fd].mods & (fdm_read|fdm_write))) {
622 addfdmodifier_fixed(fd,"read");
623 } else if (fdsetup[fd].mods & fdm_fd) {
624 addfdmodifier_fixed(fd,"write");
626 addfdmodifier_fixed(fd,"overwrite");
629 if (fdsetup[fd].mods & fdm_fd) {
630 copyfd= strtofd(value,0,
631 "value part of argument to --file with fd modifier");
632 r= fstat(copyfd,&stab);
634 if (oip) fsyscallerror("check filedescriptor %lu (named as target of file "
635 "descriptor redirection for %lu)",copyfd,fd);
636 else fsyscallerror("check basic filedescriptor %lu at program start",copyfd);
638 fdsetup[fd].copyfd= copyfd;
642 static void of_fdwait(const struct optioninfo *oip, const char *value, char *key) {
643 const struct fdmodifierinfo *fdmip;
646 fd= strtofd(key,0,"first part of argument to --fdwait");
647 if (fd >= fdsetupsize || !fdsetup[fd].filename)
648 usageerror("file descriptor %d specified in --fdwait option is not open",fd);
649 for (fdmip= fdmodifierinfos; fdmip->string && strcmp(fdmip->string,value); fdmip++);
650 if (!fdmip->string || !(fdmip->implies & (fdm_wait|fdm_nowait|fdm_close)))
651 usageerror("value for --fdwait must be `wait', `nowait' or `close', not `%s'",value);
652 fdsetup[fd].mods &= ~(fdm_wait|fdm_nowait|fdm_close);
653 fdsetup[fd].mods |= fdmip->implies;
656 static void of_defvar(const struct optioninfo *oip, const char *value, char *key) {
660 usageerror("empty string not allowed as variable name");
661 if (strlen(key)>MAX_GENERAL_STRING)
662 usageerror("variable name `%s' is far too long",key);
663 if (strlen(value)>MAX_GENERAL_STRING)
664 usageerror("variable `%s' has value `%s' which is far too long",key,value);
665 for (i=0; i<defvarused && strcmp(defvararray[i].key,key); i++);
666 if (defvarused >= MAX_ARGSDEFVAR) usageerror("far too many --defvar or -D options");
667 if (i>=defvaravail) {
668 defvaravail+=10; defvaravail<<=1;
669 defvararray= xrealloc(defvararray,sizeof(struct constkeyvaluepair)*defvaravail);
671 if (i==defvarused) defvarused++;
672 defvararray[i].key= key;
673 defvararray[i].value= value;
676 static void of_timeout(const struct optioninfo *oip, const char *value, char *key) {
681 ul= strtoul(value,&endp,10);
683 usageerror("timeout value `%s' must be a plain decimal string",value);
684 if (ul>INT_MAX) usageerror("timeout value %lu too large",ul);
688 static void of_signals(const struct optioninfo *oip, const char *value, char *key) {
689 unsigned long numvalue;
693 numvalue= strtoul(value,&endp,10);
694 if (errno || *endp) {
695 if (!strcmp(value,"number")) signalsexit= se_number;
696 else if (!strcmp(value,"number-nocore")) signalsexit= se_numbernocore;
697 else if (!strcmp(value,"highbit")) signalsexit= se_highbit;
698 else if (!strcmp(value,"stdout")) signalsexit= se_stdout;
699 else usageerror("value `%s' for --signals not understood",value);
701 if (numvalue<0 || numvalue>255)
702 usageerror("value %lu for --signals not 0...255",numvalue);
703 signalsexit= numvalue;
707 static void of_sigpipe(const struct optioninfo *oip, const char *value, char *key) {
711 static void of_hidecwd(const struct optioninfo *oip, const char *value, char *key) {
715 static void of_help(const struct optioninfo *oip, const char *value, char *key) {
717 if (fclose(stdout)) syscallerror("fclose stdout after writing usage message");
721 static void of_version(const struct optioninfo *oip, const char *value, char *key) {
722 if (puts(VERSION VEREXT) == EOF || fclose(stdout))
723 syscallerror("write version number");
727 static void of_copyright(const struct optioninfo *oip, const char *value, char *key) {
729 " userv - user service daemon and client; copyright (C)1996-1999 Ian Jackson\n\n"
730 " This is free software; you can redistribute it and/or modify it under the\n"
731 " terms of the GNU General Public License as published by the Free Software\n"
732 " Foundation; either version 2 of the License, or (at your option) any\n"
733 " later version.\n\n"
734 " This program is distributed in the hope that it will be useful, but\n"
735 " WITHOUT ANY WARRANTY; without even the implied warranty of\n"
736 " MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General\n"
737 " Public License for more details.\n\n"
738 " You should have received a copy of the GNU General Public License along\n"
739 " with userv; if not, write to Ian Jackson <ian@davenant.greenend.org.uk> or\n"
740 " to the Free Software Foundation, 59 Temple Place - Suite 330, Boston,\n"
741 " MA 02111-1307, USA.\n",
742 stdout) < 0) syscallerror("write usage to stderr");
746 static void of_builtin(const struct optioninfo *oip, const char *value, char *key) {
747 overridetype= ot_builtin;
750 static void of_override(const struct optioninfo *oip, const char *value, char *key) {
751 overridetype= ot_string;
752 overridevalue= value;
755 static void of_overridefile(const struct optioninfo *oip,
756 const char *value, char *key) {
757 overridetype= ot_file;
758 overridevalue= value;
761 static void of_spoofuser(const struct optioninfo *oip,
762 const char *value, char *key) {
766 const struct optioninfo optioninfos[]= {
767 { 'f', "file", 2, of_file },
768 { 'w', "fdwait", 2, of_fdwait },
769 { 'D', "defvar", 2, of_defvar },
770 { 't', "timeout", 1, of_timeout },
771 { 'S', "signals", 1, of_signals },
772 { 'P', "sigpipe", 0, of_sigpipe },
773 { 'H', "hidecwd", 0, of_hidecwd },
774 { 'B', "builtin", 0, of_builtin },
775 { 'h', "help", 0, of_help },
776 { 0, "version", 0, of_version },
777 { 0, "copyright", 0, of_copyright },
778 { 0, "override", 1, of_override },
779 { 0, "override-file", 1, of_overridefile },
780 { 0, "spoof-user", 1, of_spoofuser },
784 static void callvalueoption(const struct optioninfo *oip, char *arg) {
786 if (oip->values == 2) {
787 equals= strchr(arg,'=');
790 usageerror("option --%s (-%c) passed argument `%s' with no `='",
791 oip->full,oip->abbrev,arg);
793 usageerror("option --%s passed argument `%s' with no `='",
797 (oip->fn)(oip,equals,arg);
799 (oip->fn)(oip,arg,0);
804 * Main thread main processing functions - in order of execution.
807 static void security_init(void) {
808 /* May not open any file descriptors. */
810 mypid= getpid(); if (mypid == (pid_t)-1) syscallerror("getpid");
811 myuid= getuid(); if (myuid == (uid_t)-1) syscallerror("getuid");
812 mygid= getgid(); if (mygid == (gid_t)-1) syscallerror("getgid");
813 ngids= getgroups(0,0); if (ngids == -1) syscallerror("getgroups(0,0)");
814 gidarray= xmalloc(sizeof(gid_t)*ngids);
815 if (getgroups(ngids,gidarray) != ngids) syscallerror("getgroups(ngids,)");
819 if (ngids > MAX_GIDS) miscerror("caller is in far too many gids");
822 static void parse_arguments(int *argcp, char *const **argvp) {
823 static char fd0key[]= "stdin,fd,read";
824 static char fd1key[]= "stdout,fd,write";
825 static char fd2key[]= "stderr,fd,write";
829 const struct optioninfo *oip;
833 of_file(0,"stdin",fd0key);
834 of_file(0,"stdout",fd1key);
835 of_file(0,"stderr",fd2key);
837 for (argpp= *argvp+1;
838 (argp= *argpp) && *argp == '-' && argp[1];
840 if (!*++argp) usageerror("unknown option/argument `%s'",*argpp);
841 if (*argp == '-') { /* Two hyphens */
842 if (!*++argp) { argpp++; break; /* End of options. */ }
843 for (oip= optioninfos; oip->full && strcmp(oip->full,argp); oip++);
844 if (!oip->full) usageerror("unknown long option `%s'",*argpp);
846 if (!argpp[1]) usageerror("long option `%s' needs a value",*argpp);
847 callvalueoption(oip,*++argpp);
852 for (; *argp; argp++) {
853 for (oip= optioninfos; oip->full && oip->abbrev != *argp; oip++);
854 if (!oip->full) usageerror("unknown short option `-%c' in argument `%s'",
860 if (!argpp[1]) usageerror("short option `-%c' in argument `%s' needs"
861 " a value",*argp,*argpp);
864 callvalueoption(oip,argp);
865 break; /* No more options in this argument, go on to the next one. */
872 if (overridetype == ot_builtin) {
875 if (!*argpp) usageerror("no service user given after options");
876 serviceuser= *argpp++;
878 if (!*argpp) usageerror(overridetype == ot_builtin ?
879 "no service name given after options and service user" :
880 "no builtin service given after options");
882 *argcp-= (argpp-*argvp);
885 if (*argcp > MAX_ARGSDEFVAR) usageerror("far too many arguments");
887 for (fd=0; fd<fdsetupsize; fd++) {
888 if (!fdsetup[fd].filename) continue;
889 if (fdsetup[fd].mods & (fdm_wait|fdm_nowait|fdm_close)) continue;
890 assert(fdsetup[fd].mods & (fdm_read|fdm_write));
891 fdsetup[fd].mods |= (fdsetup[fd].mods & fdm_read) ? fdm_close : fdm_wait;
895 static void determine_users(void) {
903 loginname= getenv("LOGNAME");
904 if (!loginname) loginname= getenv("USER");
906 pw= getpwnam(loginname);
907 if (!pw || pw->pw_uid != myuid) loginname= 0;
910 pw= getpwuid(myuid); if (!pw) miscerror("cannot determine your login name");
911 loginname= xstrsave(pw->pw_name);
914 if (!strcmp(serviceuser,"-")) serviceuser= loginname;
915 pw= getpwnam(serviceuser);
916 if (!pw) miscerror("requested service user `%s' is not a user",serviceuser);
917 serviceuid= pw->pw_uid;
919 if ((overridetype != ot_none || spoofuser) && myuid != 0 && myuid != serviceuid)
920 miscerror("--override and --spoof options only available to root or to"
921 " the user who will be providing the service");
924 loginname= spoofuser;
925 pw= getpwnam(loginname);
926 if (!pw) miscerror("spoofed login name `%s' is not valid",loginname);
927 spoofuid= pw->pw_uid;
928 spoofgid= pw->pw_gid;
929 ngidssize= ngids; ngids= 0;
932 gidarray= xrealloc(gidarray,sizeof(gid_t)*ngidssize);
934 gidarray[ngids++]= spoofgid;
935 while ((gr= getgrent())) { /* ouch! getgrent has no error behaviour! */
936 for (mem= gr->gr_mem; *mem && strcmp(*mem,loginname); mem++);
938 if (ngids>=ngidssize) {
939 if (ngids>=MAX_GIDS) miscerror("spoofed user is member of too many groups");
940 ngidssize= (ngids+5)<<1;
941 gidarray= xrealloc(gidarray,sizeof(gid_t)*ngidssize);
943 gidarray[ngids++]= gr->gr_gid;
948 static void determine_cwd(void) {
949 cwdbufsize= 0; cwdbuf= 0;
954 if (cwdbufsize > MAX_GENERAL_STRING) { cwdbufsize= 0; free(cwdbuf); break; }
955 cwdbufsize <<= 1; cwdbufsize+= 100;
956 cwdbuf= xrealloc(cwdbuf,cwdbufsize);
957 cwdbuf[cwdbufsize-1]= 0;
958 if (getcwd(cwdbuf,cwdbufsize-1)) { cwdbufsize= strlen(cwdbuf); break; }
959 if (errno != ERANGE) { cwdbufsize= 0; free(cwdbuf); break; }
963 static void process_override(const char *servicename) {
967 switch (overridetype) {
973 l= strlen(servicename);
974 if (l >= MAX_OVERRIDE_LEN-20)
975 miscerror("builtin service string is too long (%d, max is %d)",
976 l,MAX_OVERRIDE_LEN-21);
979 snprintf(ovbuf,l,"execute-builtin %s\n",servicename);
980 ovused= strlen(ovbuf);
983 l= strlen(overridevalue);
984 if (l >= MAX_OVERRIDE_LEN)
985 miscerror("override string is too long (%d, max is %d)",l,MAX_OVERRIDE_LEN-1);
987 snprintf(ovbuf,l+2,"%s\n",overridevalue);
991 ovfile= fopen(overridevalue,"r");
992 if (!ovfile) fsyscallerror("open overriding configuration file `%s'",overridevalue);
993 ovbuf= 0; ovavail= ovused= 0;
994 while ((c= getc(ovfile)) != EOF) {
995 if (!c) miscerror("overriding config file `%s' contains null(s)",overridevalue);
996 if (ovused >= MAX_OVERRIDE_LEN)
997 miscerror("override file is too long (max is %d)",MAX_OVERRIDE_LEN);
998 if (ovused >= ovavail) {
999 ovavail+=80; ovavail<<=2; ovbuf= xrealloc(ovbuf,ovavail);
1003 if (ferror(ovfile) || fclose(ovfile))
1004 fsyscallerror("read overriding configuration file `%s'",overridevalue);
1005 ovbuf= xrealloc(ovbuf,ovused+1);
1013 static int server_connect(void) {
1014 struct sockaddr_un ssockname;
1016 struct sigaction sig;
1020 sigaddset(&sset,SIGCHLD);
1021 sigaddset(&sset,SIGALRM);
1022 sigaddset(&sset,SIGPIPE);
1023 if (sigprocmask(SIG_UNBLOCK,&sset,0)) syscallerror("preliminarily unblock signals");
1025 sig.sa_handler= SIG_IGN;
1026 sigemptyset(&sig.sa_mask);
1028 if (sigaction(SIGPIPE,&sig,0)) syscallerror("ignore sigpipe");
1030 sfd= socket(AF_UNIX,SOCK_STREAM,0);
1031 if (!sfd) syscallerror("create client socket");
1033 assert(sizeof(ssockname.sun_path) > sizeof(RENDEZVOUSPATH));
1034 ssockname.sun_family= AF_UNIX;
1035 strcpy(ssockname.sun_path,RENDEZVOUSPATH);
1037 while (connect(sfd,(struct sockaddr*)&ssockname,sizeof(ssockname))) {
1038 if (errno == ECONNREFUSED || errno == ENOENT)
1039 syscallerror("uservd daemon is not running - service not available");
1041 fsyscallerror("unable to connect to uservd daemon: %m");
1047 static void server_handshake(int sfd) {
1048 srfile= fdopen(sfd,"r");
1049 if (!srfile) syscallerror("turn socket fd into FILE* for read");
1050 if (setvbuf(srfile,0,_IOFBF,BUFSIZ)) syscallerror("set buffering on socket reads");
1052 swfile= fdopen(sfd,"w");
1053 if (!swfile) syscallerror("turn socket fd into FILE* for write");
1054 if (setvbuf(swfile,0,_IOFBF,BUFSIZ)) syscallerror("set buffering on socket writes");
1056 xfread(&opening_mbuf,sizeof(opening_mbuf),srfile);
1057 checkmagic(opening_mbuf.magic,OPENING_MAGIC,"in opening message");
1058 if (memcmp(protocolchecksumversion,opening_mbuf.protocolchecksumversion,PCSUMSIZE))
1059 protoerror("protocol version checksum mismatch - server not same as client");
1062 static void server_preparepipes(void) {
1063 char pipepathbuf[PIPEPATHMAXLEN+2];
1066 for (fd=0; fd<fdsetupsize; fd++) {
1067 if (!fdsetup[fd].filename) continue;
1068 pipepathbuf[PIPEPATHMAXLEN]= 0;
1069 sprintf(pipepathbuf, PIPEPATHFORMAT,
1070 (unsigned long)mypid, (unsigned long)opening_mbuf.serverpid, fd);
1071 assert(!pipepathbuf[PIPEPATHMAXLEN]);
1073 if (unlink(pipepathbuf) && errno != ENOENT)
1074 fsyscallerror("remove any old pipe `%s'",pipepathbuf);
1075 if (mkfifo(pipepathbuf,0600)) /* permissions are irrelevant */
1076 fsyscallerror("create pipe `%s'",pipepathbuf);
1077 tempfd= open(pipepathbuf,O_RDWR);
1078 if (tempfd<0) fsyscallerror("prelim open pipe `%s' for read+write",pipepathbuf);
1079 assert(fdsetup[fd].mods & (fdm_read|fdm_write));
1081 open(pipepathbuf, (fdsetup[fd].mods & fdm_read) ? O_WRONLY : O_RDONLY);
1082 if (fdsetup[fd].pipefd<0) fsyscallerror("real open pipe `%s'",pipepathbuf);
1083 if (close(tempfd)) fsyscallerror("close prelim fd onto pipe `%s'",pipepathbuf);
1088 static void server_sendrequest(int argc, char *const *argv) {
1089 struct request_msg request_mbuf;
1093 memset(&request_mbuf,0,sizeof(request_mbuf));
1094 request_mbuf.magic= REQUEST_MAGIC;
1095 request_mbuf.clientpid= getpid();
1096 request_mbuf.serviceuserlen= strlen(serviceuser);
1097 request_mbuf.servicelen= strlen(argv[0]);
1098 request_mbuf.loginnamelen= strlen(loginname);
1099 request_mbuf.spoofed= spoofuser ? 1 : 0;
1100 request_mbuf.cwdlen= cwdbufsize;
1101 request_mbuf.callinguid= spoofuid;
1102 request_mbuf.ngids= ngids+1;
1103 request_mbuf.nreadfds= 0;
1104 request_mbuf.nwritefds= 0;
1105 for (fd=0; fd<fdsetupsize; fd++) {
1106 if (!fdsetup[fd].filename) continue;
1107 assert(fdsetup[fd].mods & (fdm_write|fdm_read));
1108 if (fdsetup[fd].mods & fdm_write) request_mbuf.nwritefds++;
1109 else request_mbuf.nreadfds++;
1111 request_mbuf.nargs= argc-1;
1112 request_mbuf.nvars= defvarused;
1113 request_mbuf.overridelen= ovused;
1114 xfwrite(&request_mbuf,sizeof(request_mbuf),swfile);
1115 xfwrite(serviceuser,sizeof(*serviceuser)*request_mbuf.serviceuserlen,swfile);
1116 xfwrite(argv[0],sizeof(*argv[0])*request_mbuf.servicelen,swfile);
1117 xfwrite(loginname,sizeof(*loginname)*request_mbuf.loginnamelen,swfile);
1118 xfwrite(cwdbuf,sizeof(*cwdbuf)*request_mbuf.cwdlen,swfile);
1119 if (ovused>=0) xfwrite(ovbuf,sizeof(*ovbuf)*ovused,swfile);
1120 xfwrite(&spoofgid,sizeof(gid_t),swfile);
1121 xfwrite(gidarray,sizeof(gid_t)*ngids,swfile);
1122 xfwritefds(fdm_read,request_mbuf.nreadfds,swfile);
1123 xfwritefds(fdm_write,request_mbuf.nwritefds,swfile);
1124 for (i=1; i<argc; i++)
1125 xfwritestring(argv[i],swfile);
1126 for (i=0; i<defvarused; i++) {
1127 xfwritestring(defvararray[i].key,swfile);
1128 xfwritestring(defvararray[i].value,swfile);
1130 ul= REQUEST_END_MAGIC; xfwrite(&ul,sizeof(ul),swfile);
1134 static void server_awaitconfirm(void) {
1135 struct progress_msg progress_mbuf;
1137 getprogress(&progress_mbuf,srfile);
1138 if (progress_mbuf.type != pt_ok)
1139 protoerror("progress message during configuration phase"
1140 " unexpected type %d",progress_mbuf.type);
1143 static void prepare_asynchsignals(void) {
1144 static char stderrbuf[BUFSIZ], stdoutbuf[BUFSIZ];
1146 struct sigaction sig;
1148 if (setvbuf(stderr,stderrbuf,_IOLBF,sizeof(stderrbuf)))
1149 syscallerror("set buffering on stderr");
1150 if (setvbuf(stdout,stdoutbuf,_IOFBF,sizeof(stdoutbuf)))
1151 syscallerror("set buffering on stdout");
1153 sig.sa_handler= sighandler_chld;
1154 sigemptyset(&sig.sa_mask);
1155 sigaddset(&sig.sa_mask,SIGCHLD);
1156 sigaddset(&sig.sa_mask,SIGALRM);
1158 if (sigaction(SIGCHLD,&sig,0)) syscallerror("set up sigchld handler");
1160 sig.sa_handler= sighandler_alrm;
1161 if (sigaction(SIGALRM,&sig,0)) syscallerror("set up sigalrm handler");
1163 if (!timeout) return;
1168 static void close_unwanted_pipes(void) {
1171 for (fd=0; fd<fdsetupsize; fd++) {
1172 if (!fdsetup[fd].filename) continue;
1173 if (close(fdsetup[fd].pipefd)) fsyscallerror("close pipe fd for %d",fd);
1174 if (fdsetup[fd].copyfd>2)
1175 if (close(fdsetup[fd].copyfd))
1177 /* EBADF can be induced if cmd line specifies same fd twice */
1178 fsyscallerror("close real fd for %d",fd);
1182 static void catdup(const char *which, int from, int to) {
1183 if (dup2(from,to)<0) {
1184 blocksignals(SIG_BLOCK);
1185 fprintf(stderr,"userv: %s: cannot dup for %s: %s\n",which,
1186 to?"stdout":"stdin", strerror(errno));
1191 static void connect_pipes(void) {
1192 struct sigaction sig;
1193 char catnamebuf[sizeof(int)*3+30];
1197 for (fd=0; fd<fdsetupsize; fd++) {
1198 if (!fdsetup[fd].filename) continue;
1199 if (!(fdsetup[fd].mods & fdm_fd)) {
1201 open(fdsetup[fd].filename,fdsetup[fd].oflags|O_NOCTTY,0777);
1202 if (fdsetup[fd].copyfd<0)
1203 fsyscallerror("open file `%s' for fd %d",fdsetup[fd].filename,fd);
1205 blocksignals(SIG_BLOCK);
1207 fdsetup[fd].catpid= child;
1208 blocksignals(SIG_UNBLOCK);
1209 if (child==-1) fsyscallerror("fork for cat for fd %d",fd);
1211 snprintf(catnamebuf,sizeof(catnamebuf),"cat fd%d",fd);
1212 catnamebuf[sizeof(catnamebuf)-1]= 0;
1213 sig.sa_handler= SIG_DFL;
1214 sigemptyset(&sig.sa_mask);
1216 if (sigaction(SIGPIPE,&sig,0)) {
1217 fprintf(stderr,"userv: %s: reset sigpipe handler for cat: %s",
1218 catnamebuf,strerror(errno));
1221 reading= fdsetup[fd].mods & fdm_read;
1222 catdup(catnamebuf, fdsetup[fd].copyfd, reading ? 0 : 1);
1223 catdup(catnamebuf, fdsetup[fd].pipefd, reading ? 1 : 0);
1224 if (close(socketfd))
1225 fsyscallerror("%s: close client socket for for cat",catnamebuf);
1226 close_unwanted_pipes();
1227 execl("/bin/cat",catnamebuf,(char*)0);
1228 fprintf(stderr,"userv: %s: cannot exec `cat': %s\n",catnamebuf,strerror(errno));
1232 close_unwanted_pipes();
1235 static void server_sendconfirm(void) {
1236 struct event_msg event_mbuf;
1238 blocksignals(SIG_BLOCK);
1239 memset(&event_mbuf,0,sizeof(event_mbuf));
1240 event_mbuf.magic= EVENT_MAGIC;
1241 event_mbuf.type= et_confirm;
1242 xfwrite(&event_mbuf,sizeof(event_mbuf),swfile);
1244 blocksignals(SIG_UNBLOCK);
1247 static int server_awaitcompletion(void) {
1248 struct progress_msg progress_mbuf;
1250 getprogress(&progress_mbuf,srfile);
1251 if (progress_mbuf.type != pt_terminated)
1252 protoerror("progress message during execution phase"
1253 " unexpected type %d",progress_mbuf.type);
1256 return progress_mbuf.data.terminated.status;
1259 static void dispose_remaining_pipes(void) {
1263 blocksignals(SIG_BLOCK);
1264 for (fd=0; fd<fdsetupsize; fd++) {
1265 if (!(fdsetup[fd].catpid!=-1 && (fdsetup[fd].mods & fdm_close))) continue;
1266 if (kill(fdsetup[fd].catpid,SIGKILL)) fsyscallerror("kill cat for %d",fd);
1267 fdsetup[fd].killed= 1;
1269 blocksignals(SIG_UNBLOCK);
1272 blocksignals(SIG_BLOCK);
1274 fd<fdsetupsize && !(fdsetup[fd].catpid!=-1 && (fdsetup[fd].mods & fdm_wait));
1276 if (fd>=fdsetupsize) break;
1278 r= sigsuspend(&sset);
1279 if (r && errno != EINTR) syscallerror("sigsuspend failed in unexpected way");
1280 blocksignals(SIG_UNBLOCK);
1284 static void NONRETURNING process_exitstatus(int status) {
1285 blocksignals(SIG_BLOCK);
1287 if (systemerror) _exit(255);
1289 if (sigpipeok && signalsexit != se_stdout && WIFSIGNALED(status) &&
1290 WTERMSIG(status)==SIGPIPE && !WCOREDUMP(status)) status= 0;
1292 switch (signalsexit) {
1294 case se_numbernocore:
1295 if (WIFEXITED(status))
1296 _exit(WEXITSTATUS(status));
1297 else if (WIFSIGNALED(status))
1298 _exit(WTERMSIG(status) + (signalsexit==se_number && WCOREDUMP(status) ? 128 : 0));
1301 if (WIFEXITED(status))
1302 _exit(WEXITSTATUS(status)<=127 ? WEXITSTATUS(status) : 127);
1303 else if (WIFSIGNALED(status) && WTERMSIG(status)<=126)
1304 _exit(WTERMSIG(status)+128);
1307 printf("\n%d %d ",(status>>8)&0x0ff,status&0x0ff);
1308 if (WIFEXITED(status))
1309 printf("exited with code %d",WEXITSTATUS(status));
1310 else if (WIFSIGNALED(status))
1311 printf("killed by %s (signal %d)%s",
1312 strsignal(WTERMSIG(status)),WTERMSIG(status),
1313 WCOREDUMP(status) ? ", core dumped " : "");
1315 printf("unknown wait status");
1317 if (ferror(stdout) || fflush(stdout)) syscallerror("write exit status to stdout");
1320 if (WIFEXITED(status))
1321 _exit(WEXITSTATUS(status));
1322 else if (WIFSIGNALED(status))
1327 fprintf(stderr,"userv: unknown wait status %d\n",status);
1331 int main(int argc, char *const *argv) {
1335 # error Do not disable assertions in this security-critical code !
1339 parse_arguments(&argc,&argv);
1342 process_override(argv[0]);
1344 socketfd= server_connect();
1346 server_handshake(socketfd);
1347 server_preparepipes();
1348 server_sendrequest(argc,argv);
1350 priv_permanentlyrevokesuspended();
1352 server_awaitconfirm();
1353 prepare_asynchsignals();
1355 server_sendconfirm();
1356 status= server_awaitcompletion();
1358 dispose_remaining_pipes();
1359 process_exitstatus(status);