3 * Source and target for executable programs
5 * (c) 1999 Straylight/Edgeware
8 /*----- Licensing notice --------------------------------------------------*
10 * This file is part of the `fwd' port forwarder.
12 * `fwd' is free software; you can redistribute it and/or modify
13 * it under the terms of the GNU General Public License as published by
14 * the Free Software Foundation; either version 2 of the License, or
15 * (at your option) any later version.
17 * `fwd' is distributed in the hope that it will be useful,
18 * but WITHOUT ANY WARRANTY; without even the implied warranty of
19 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
20 * GNU General Public License for more details.
22 * You should have received a copy of the GNU General Public License
23 * along with `fwd'; if not, write to the Free Software Foundation,
24 * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
29 /*----- Data structures ---------------------------------------------------*/
31 /* --- Resource usage --- */
35 typedef struct xlimit {
36 #define R(r, n) struct rlimit n;
42 /* --- Environment variable modifications --- */
54 /* --- Program options --- */
56 typedef struct xopts {
72 /* --- Executable program arguments --- */
74 typedef struct xargs {
80 #define XARGS_SZ(n) (sizeof(xargs) + sizeof(char *) * (n))
82 /* --- Executable endpoints --- */
86 struct xept *next, *prev;
99 /* --- Executable program data --- */
101 typedef struct xdata {
106 /* --- Executable source block --- */
108 typedef struct xsource {
113 /* --- Executable target block --- */
115 typedef struct xtarget {
120 /*----- Static variables --------------------------------------------------*/
122 static xopts exec_opts = { 1, 0, 0, 0, -1, -1, 0, &exec_opts.env };
123 static xept *xept_list;
125 static sym_table env;
127 /*----- Fiddling about with resource limits -------------------------------*/
129 #ifdef HAVE_SETRLIMIT
131 /* --- Table mapping user-level names to OS interface bits --- */
133 typedef struct rlimit_ent {
140 static rlimit_ent rlimits[] = {
141 #define R(r, n) { #n, #r, r, offsetof(xlimit, n) },
146 #define RLIMIT(xl, o) ((struct rlimit *)((char *)(xl) + (o)))
148 /* --- @rlimit_get@ --- *
150 * Arguments: @xlimit *xl@ = pointer to limit structure
154 * Use: Initializes a limit structure from the current limits.
157 static void rlimit_get(xlimit *xl)
161 for (r = rlimits; r->name; r++) {
162 if (getrlimit(r->r, RLIMIT(xl, r->off))) {
163 moan("couldn't read %s: %s", r->rname, strerror(errno));
169 /* --- @rlimit_set@ --- *
171 * Arguments: @xlimit *xl@ = pointer to limit structure
175 * Use: Sets resource limits from the supplied limits structure.
178 static void rlimit_set(xlimit *xl)
182 for (r = rlimits; r->name; r++) {
183 if (setrlimit(r->r, RLIMIT(xl, r->off))) {
184 moan("couldn't set %s: %s", r->rname, strerror(errno));
190 /* --- @rlimit_option@ --- */
192 static int rlimit_option(xlimit *xl, scanner *sc)
194 CONF_BEGIN(sc, "rlimit", "resource limit")
195 enum { w_soft, w_hard, w_both } which = w_both;
200 /* --- Find out which resource is being fiddled --- */
206 for (r = rlimits; r->name; r++) {
207 if (strncmp(sc->d.buf, r->name, sc->d.len) == 0) {
208 if (r->name[sc->d.len] == 0) {
212 error(sc, "ambiguous resource limit name `%s'", sc->d.buf);
220 rl = RLIMIT(xl, chosen->off);
223 /* --- Look for hard or soft restrictions --- */
229 if (sc->t == CTOK_WORD) {
230 if ((i = conf_enum(sc, "soft,hard",
231 ENUM_ABBREV | ENUM_NONE, "limit type")) != -1)
236 /* --- Now read the new value --- */
240 if (sc->t != CTOK_WORD)
241 error(sc, "parse error, expected limit value");
243 if (conf_enum(sc, "unlimited,infinity",
244 ENUM_ABBREV | ENUM_NONE, "limit value") > -1)
249 v = strtol(sc->d.buf, &p, 0);
251 error(sc, "parse error, invalid limit value `%s'", sc->d.buf);
252 switch (tolower((unsigned char)*p)) {
254 case 'b': v *= 512; break;
257 case 'k': v *= 1024; break;
258 default: error(sc, "parse error, invalid limit scale `%c'", *p);
263 /* --- Store the limit value away --- */
271 if (v > rl->rlim_max)
272 error(sc, "soft limit %l exceeds hard limit %l for %s",
273 v, rl->rlim_max, chosen->rname);
278 if (rl->rlim_cur > v)
289 /*----- Environment fiddling ----------------------------------------------*/
291 /* --- @xenv_option@ --- *
293 * Arguments: @xopts *xo@ = pointer to options block
294 * @scanner *sc@ = pointer to scanner
296 * Returns: Nonzero if claimed
298 * Use: Parses environment variable assignments.
301 static int xenv_option(xopts *xo, scanner *sc)
303 CONF_BEGIN(sc, "env", "environment")
306 /* --- Unset a variable --- */
308 if (strcmp(sc->d.buf, "unset") == 0) {
310 if (sc->t != CTOK_WORD)
311 error(sc, "parse error, expected environment variable name");
313 xe->name = xstrdup(sc->d.buf);
320 /* --- Clear the entire environment --- */
322 if (strcmp(sc->d.buf, "clear") == 0) {
329 /* --- Allow `set' to be omitted if there's a prefix --- */
331 if (strcmp(sc->d.buf, "set") == 0)
336 /* --- Set a variable --- */
338 if (sc->t != CTOK_WORD)
339 error(sc, "parse error, expected environment variable name");
341 xe->name = xstrdup(sc->d.buf);
345 if (sc->t != CTOK_WORD)
346 error(sc, "parse error, expected environment variable value");
347 xe->value = xstrdup(sc->d.buf);
355 xo->etail = &xe->next;
358 /* --- Nothing else to try --- */
363 /* --- @xenv_apply@ --- *
365 * Arguments: @xenv *xe@ = pointer to a variable change list
369 * Use: Modifies the environment (in @env@) according to the list.
372 static void xenv_apply(xenv *xe)
377 env_put(&env, xe->name, xe->value);
388 /* --- @xenv_destroy@ --- *
390 * Arguments: @xenv *xe@ = pointer to a variable change list
394 * Use: Frees the memory used by an environment variable change list.
397 static void xenv_destroy(xenv *xe)
409 /*----- Miscellaneous good things -----------------------------------------*/
411 /* --- @x_tidy@ --- *
413 * Arguments: @xargs *xa@ = pointer to an arguments block
414 * @xopts *xo@ = pointer to an options block
418 * Use: Releases a reference to argument and options blocks.
421 static void x_tidy(xargs *xa, xopts *xo)
429 xenv_destroy(xo->env);
434 /*----- Executable endpoints ----------------------------------------------*/
436 /* --- @attach@ --- */
438 static void xept_error(char */*p*/, size_t /*len*/, void */*v*/);
440 static void xept_attach(endpt *e, reffd *in, reffd *out)
442 xept *xe = (xept *)e;
446 /* --- Make a pipe for standard error --- */
449 fw_log(-1, "[%s] couldn't create pipe: %s", xe->desc, strerror(errno));
452 fdflags(fd[0], O_NONBLOCK, O_NONBLOCK, FD_CLOEXEC, FD_CLOEXEC);
454 /* --- Fork a child, and handle an error if there was one --- */
456 if ((kid = fork()) == -1) {
457 fw_log(-1, "[%s] couldn't fork: %s", xe->desc, strerror(errno));
463 /* --- Do the child thing --- */
469 /* --- Fiddle with the file descriptors --- *
471 * Attach the other endpoint's descriptors to standard input and output.
472 * Attach my pipe to standard error. Mark everything as blocking and
473 * not-to-be-closed-on-exec at this end.
477 md[0].cur = in->fd; md[0].want = STDIN_FILENO;
478 md[1].cur = out->fd; md[1].want = STDOUT_FILENO;
479 md[2].cur = fd[1]; md[2].want = STDERR_FILENO;
481 moan("couldn't manipulate file descriptors: %s", strerror(errno));
485 fdflags(STDIN_FILENO, O_NONBLOCK, 0, FD_CLOEXEC, 0);
486 fdflags(STDOUT_FILENO, O_NONBLOCK, 0, FD_CLOEXEC, 0);
487 fdflags(STDERR_FILENO, O_NONBLOCK, 0, FD_CLOEXEC, 0);
489 /* --- First of all set the @chroot@ prison --- */
491 if (xo->root && chroot(xo->root)) {
492 moan("couldn't set `%s' as filesystem root: %s",
493 xo->root, strerror(errno));
497 /* --- Now set the current directory --- */
499 if (xo->dir ? chdir(xo->dir) : xo->root ? chdir("/") : 0) {
500 moan("couldn't set `%s' as current directory: %s",
501 xo->dir ? xo->dir : "/", strerror(errno));
505 /* --- Set the resource limits --- */
507 #ifdef HAVE_SETRLIMIT
511 /* --- Set group id --- */
513 if (xo->gid != (gid_t)-1) {
514 if (setgid(xo->gid)) {
515 moan("couldn't set gid %i: %s", xo->gid, strerror(errno));
518 #ifdef HAVE_SETGROUPS
519 if (setgroups(1, &xo->gid))
520 moan("warning: couldn't set group list to %i: %s", xo->gid,
525 /* --- Set uid --- */
527 if (xo->uid != (uid_t)-1) {
528 if (setuid(xo->uid)) {
529 moan("couldn't set uid %i: %s", xo->uid, strerror(errno));
534 /* --- Play with signal dispositions --- */
536 signal(SIGPIPE, SIG_DFL);
538 /* --- Fiddle with the environment --- */
540 xenv_apply(exec_opts.env);
541 xenv_apply(xe->xo->env);
542 environ = env_export(&env);
544 /* --- Run the program --- */
546 execvp(xe->xa->file, xe->xa->argv);
547 moan("couldn't execute `%s': %s", xe->xa->file, strerror(errno));
551 /* --- The child's done; see to the parent --- */
554 selbuf_init(&xe->err, sel, fd[0], xept_error, xe);
556 xe->next = xept_list;
559 xept_list->prev = xe;
561 if (!(xe->xo->f & XF_NOLOG))
562 fw_log(-1, "[%s] started with pid %i", xe->desc, kid);
567 /* --- @xept_file@ --- */
569 static void xept_file(endpt *e, endpt *f)
571 xept *xe = (xept *)e;
575 /* --- @xept_close@ --- */
577 static void xept_close(endpt *e)
579 xept *xe = (xept *)e;
582 xe->f->ops->close(xe->f);
583 x_tidy(xe->xa, xe->xo);
589 /* --- @xept_destroy@ --- */
591 static void xept_destroy(xept *xe)
593 /* --- First emit the news about the process --- */
595 if (xe->xo->f & XF_NOLOG)
597 else if (WIFEXITED(xe->st)) {
598 if (WEXITSTATUS(xe->st) == 0)
599 fw_log(-1, "[%s] pid %i exited successfully", xe->desc, xe->kid);
601 fw_log(-1, "[%s] pid %i failed: status %i",
602 xe->desc, xe->kid, WEXITSTATUS(xe->st));
604 } else if (WIFSIGNALED(xe->st)) {
606 #ifdef HAVE_STRSIGNAL
607 s = strsignal(WTERMSIG(xe->st));
608 #elif HAVE__SYS_SIGLIST
609 s = _sys_siglist[WTERMSIG(xe->st)];
612 sprintf(buf, "signal %i", WTERMSIG(xe->st));
615 fw_log(-1, "[%s] pid %i failed: %s", xe->desc, xe->kid, s);
617 fw_log(-1, "[%s] pid %i failed: unrecognized status", xe->desc, xe->kid);
619 /* --- Free up the parent-side resources --- */
622 xe->next->prev = xe->prev;
624 xe->prev->next = xe->next;
626 xept_list = xe->next;
630 xe->f->ops->close(xe->f);
631 x_tidy(xe->xa, xe->xo);
636 /* --- @xept_chld@ --- *
638 * Arguments: @int n@ = signal number
639 * @void *p@ = uninteresting pointer
643 * Use: Deals with child death situations.
646 static void xept_chld(int n, void *p)
651 while ((kid = waitpid(-1, &st, WNOHANG)) > 0) {
652 xept *xe = xept_list;
656 if (kid == xxe->kid) {
658 xxe->e.f |= XEF_EXIT;
659 if (xxe->e.f & XEF_CLOSE)
667 /* --- @xept_error@ --- *
669 * Arguments: @char *p@ = pointer to string read from stderr
670 * @size_t len@ = length of the string
671 * @void *v@ = pointer to by endpoint
675 * Use: Handles error reports from a child process.
678 static void xept_error(char *p, size_t len, void *v)
682 fw_log(-1, "[%s] pid %i: %s", xe->desc, xe->kid, p);
684 close(xe->err.reader.fd);
685 selbuf_destroy(&xe->err);
686 xe->e.f |= XEF_CLOSE;
687 if (xe->e.f & XEF_EXIT)
692 /* --- Endpoint operations --- */
694 static endpt_ops xept_ops = { xept_attach, xept_file, 0, xept_close };
696 /*----- General operations on sources and targets -------------------------*/
698 /* --- @exec_init@ --- *
704 * Use: Initializes the executable problem source and target.
709 #ifdef HAVE_SETRLIMIT
710 rlimit_get(&exec_opts.xl);
712 sig_add(&xept_sig, SIGCHLD, xept_chld, 0);
714 env_import(&env, environ);
717 /* --- @exec_option@ --- */
719 static int exec_option(xdata *x, scanner *sc)
721 xopts *xo = x ? x->xo : &exec_opts;
723 CONF_BEGIN(sc, "exec", "executable");
725 /* --- Logging settings --- */
727 if (strcmp(sc->d.buf, "logging") == 0 ||
728 strcmp(sc->d.buf, "log") == 0) {
732 if (conf_enum(sc, "no,yes", ENUM_ABBREV, "logging status"))
739 /* --- Current directory setting --- *
741 * Lots of possibilities to guard against possible brainoes.
744 if (strcmp(sc->d.buf, "dir") == 0 ||
745 strcmp(sc->d.buf, "cd") == 0 ||
746 strcmp(sc->d.buf, "chdir") == 0 ||
747 strcmp(sc->d.buf, "cwd") == 0) {
753 xo->dir = xstrdup(d.buf);
758 /* --- Set a chroot prison --- */
760 if (strcmp(sc->d.buf, "root") == 0 ||
761 strcmp(sc->d.buf, "chroot") == 0) {
767 xo->root = xstrdup(d.buf);
772 /* --- Set the target user id --- */
774 if (strcmp(sc->d.buf, "uid") == 0 ||
775 strcmp(sc->d.buf, "user") == 0) {
779 if (sc->t != CTOK_WORD)
780 error(sc, "parse error, expected user name or uid");
781 if (isdigit((unsigned char)*sc->d.buf))
782 xo->uid = atoi(sc->d.buf);
784 struct passwd *pw = getpwnam(sc->d.buf);
786 error(sc, "unknown user name `%s'", sc->d.buf);
787 xo->uid = pw->pw_uid;
793 /* --- Set the target group id --- */
795 if (strcmp(sc->d.buf, "gid") == 0 ||
796 strcmp(sc->d.buf, "group") == 0) {
800 if (sc->t != CTOK_WORD)
801 error(sc, "parse error, expected group name or gid");
802 if (isdigit((unsigned char)*sc->d.buf))
803 xo->gid = atoi(sc->d.buf);
805 struct group *gr = getgrnam(sc->d.buf);
807 error(sc, "unknown user name `%s'", sc->d.buf);
808 xo->gid = gr->gr_gid;
814 /* --- Now try resource limit settings --- */
816 #ifdef HAVE_SETRLIMIT
817 if (rlimit_option(&xo->xl, sc))
821 /* --- And then environment settings --- */
823 if (xenv_option(xo, sc))
826 /* --- Nothing found --- */
831 /* --- @exec_desc@ --- */
833 static void exec_desc(xdata *x, dstr *d)
837 dstr_puts(d, "exec ");
838 if (strcmp(x->xa->file, x->xa->argv[0]) != 0) {
839 dstr_puts(d, x->xa->file);
842 for (p = x->xa->argv; *p; p++) {
851 /* --- @exec_read@ --- */
853 static void exec_read(xdata *x, scanner *sc)
859 /* --- Read the first word --- *
861 * This is either a shell command or the actual program to run.
864 if (sc->t == CTOK_WORD) {
865 dstr_putd(&d, &sc->d); d.len++;
870 /* --- See if there's a list of arguments --- *
872 * If not, then the thing I saw was a shell command, so build the proper
873 * arguments for that.
879 error(sc, "parse error, expected shell command or argument list");
880 xa = xmalloc(XARGS_SZ(3) + 8 + 3 + d.len);
881 p = (char *)(xa->argv + 4);
884 xa->argv[0] = p; memcpy(p, "/bin/sh", 8); p += 8;
885 xa->argv[1] = p; memcpy(p, "-c", 3); p += 3;
886 xa->argv[2] = p; memcpy(p, d.buf, d.len); p += d.len;
890 /* --- Snarf in a list of arguments --- */
897 /* --- Strip off the leading `[' --- *
899 * Allow various handy filename characters to be entered without quoting.
902 conf_undelim(sc, "=:/.", "=:/.");
905 /* --- Read a sequence of arguments --- */
907 while (sc->t == CTOK_WORD) {
908 dstr_putd(&d, &sc->d); d.len++;
912 conf_undelim(sc, 0, 0);
914 /* --- Expect the closing `]' --- */
917 error(sc, "parse error, missing `]'");
920 /* --- If there are no arguments, whinge --- */
923 error(sc, "must specify at least one argument");
925 /* --- Allocate a lump of memory for the array --- */
927 xa = xmalloc(XARGS_SZ(argc) + d.len);
930 p = (char *)(v + argc + 1);
931 memcpy(p, d.buf, d.len);
936 /* --- Start dumping addresses into the @argv@ array --- */
940 while (*p++ && p < q)
948 /* --- Do some other setting up --- */
952 x->xo = CREATE(xopts);
958 /* --- @exec_endpt@ --- */
960 static endpt *exec_endpt(xdata *x, const char *desc)
962 xept *xe = CREATE(xept);
963 xe->e.ops = &xept_ops;
967 xe->xa = x->xa; xe->xa->ref++;
968 xe->xo = x->xo; xe->xo->ref++;
971 xe->desc = xstrdup(desc);
975 /* --- @exec_destroy@ --- */
977 static void exec_destroy(xdata *x)
979 x_tidy(x->xa, x->xo);
982 /*----- Source definition -------------------------------------------------*/
984 /* --- @option@ --- */
986 static int xsource_option(source *s, scanner *sc)
988 xsource *xs = (xsource *)s;
989 return (exec_option(xs ? &xs->x : 0, sc));
994 static source *xsource_read(scanner *sc)
998 if (!conf_prefix(sc, "exec"))
1000 xs = CREATE(xsource);
1001 xs->s.ops = &xsource_ops;
1003 exec_read(&xs->x, sc);
1007 /* --- @attach@ --- */
1009 static void xsource_destroy(source */*s*/);
1011 static void xsource_attach(source *s, scanner *sc, target *t)
1013 xsource *xs = (xsource *)s;
1016 /* --- Set up the source description string --- */
1020 exec_desc(&xs->x, &d);
1021 dstr_puts(&d, " -> ");
1022 dstr_puts(&d, t->desc);
1023 xs->s.desc = xstrdup(d.buf);
1027 /* --- Create the endpoints --- */
1029 if ((ee = t->ops->create(t, xs->s.desc)) == 0)
1031 if ((e = exec_endpt(&xs->x, xs->s.desc)) == 0) {
1035 endpt_join(e, ee, xs->s.desc);
1037 /* --- Dispose of source and target --- */
1041 xsource_destroy(&xs->s);
1044 /* --- @destroy@ --- */
1046 static void xsource_destroy(source *s)
1048 xsource *xs = (xsource *)s;
1050 exec_destroy(&xs->x);
1054 /* --- Executable source operations --- */
1056 source_ops xsource_ops = {
1058 xsource_option, xsource_read, xsource_attach, xsource_destroy
1061 /*----- Exec target description -------------------------------------------*/
1063 /* --- @option@ --- */
1065 static int xtarget_option(target *t, scanner *sc)
1067 xtarget *xt = (xtarget *)t;
1068 return (exec_option(xt ? &xt->x : 0, sc));
1071 /* --- @read@ --- */
1073 static target *xtarget_read(scanner *sc)
1078 if (!conf_prefix(sc, "exec"))
1080 xt = CREATE(xtarget);
1081 xt->t.ops = &xtarget_ops;
1082 exec_read(&xt->x, sc);
1083 exec_desc(&xt->x, &d);
1084 xt->t.desc = xstrdup(d.buf);
1089 /* --- @create@ --- */
1091 static endpt *xtarget_create(target *t, const char *desc)
1093 xtarget *xt = (xtarget *)t;
1094 endpt *e = exec_endpt(&xt->x, desc);
1098 /* --- @destroy@ --- */
1100 static void xtarget_destroy(target *t)
1102 xtarget *xt = (xtarget *)t;
1104 exec_destroy(&xt->x);
1108 /* --- Exec target operations --- */
1110 target_ops xtarget_ops = {
1112 xtarget_option, xtarget_read, 0, xtarget_create, xtarget_destroy
1115 /*----- That's all, folks -------------------------------------------------*/