![[BACK]](/icons/back.gif){kind=icon}
Return to child.c CVS log ![[TXT]](/icons/text.gif){kind=icon}
![[DIR]](/icons/dir.gif){kind=icon}
Up to [local] / src / usr.bin / rdist|
Return to child.c CVS log | Up to [local] / src / usr.bin / rdist |
1.9 ! millert 1: /* $OpenBSD: child.c,v 1.8 1999/02/04 23:18:56 millert Exp $ */
1.3 deraadt 2:
1.1 dm 3: /*
4: * Copyright (c) 1983 Regents of the University of California.
5: * All rights reserved.
6: *
7: * Redistribution and use in source and binary forms, with or without
8: * modification, are permitted provided that the following conditions
9: * are met:
10: * 1. Redistributions of source code must retain the above copyright
11: * notice, this list of conditions and the following disclaimer.
12: * 2. Redistributions in binary form must reproduce the above copyright
13: * notice, this list of conditions and the following disclaimer in the
14: * documentation and/or other materials provided with the distribution.
15: * 3. All advertising materials mentioning features or use of this software
16: * must display the following acknowledgement:
17: * This product includes software developed by the University of
18: * California, Berkeley and its contributors.
19: * 4. 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.
22: *
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
33: * SUCH DAMAGE.
34: */
35:
36: #ifndef lint
1.7 millert 37: #if 0
1.1 dm 38: static char RCSid[] =
1.7 millert 39: "$From: child.c,v 6.28 1996/02/22 19:30:09 mcooper Exp $";
40: #else
41: static char RCSid[] =
1.9 ! millert 42: "$OpenBSD: child.c,v 1.8 1999/02/04 23:18:56 millert Exp $";
1.7 millert 43: #endif
1.1 dm 44:
45: static char sccsid[] = "@(#)docmd.c 5.1 (Berkeley) 6/6/85";
46:
47: static char copyright[] =
48: "@(#) Copyright (c) 1983 Regents of the University of California.\n\
49: All rights reserved.\n";
50: #endif /* not lint */
51:
52: /*
53: * Functions for rdist related to children
54: */
55:
56: #include "defs.h"
57: #include <sys/types.h>
58: #include <sys/wait.h>
59: #if defined(NEED_SYS_SELECT_H)
60: #include <sys/select.h>
61: #endif /* NEED_SYS_SELECT_H */
62:
63: typedef enum _PROCSTATE {
64: PSrunning,
65: PSdead
66: } PROCSTATE;
67:
68: /*
69: * Structure for child rdist processes mainted by the parent
70: */
71: struct _child {
72: char *c_name; /* Name of child */
73: int c_readfd; /* Read file descriptor */
74: pid_t c_pid; /* Process ID */
75: PROCSTATE c_state; /* Running? */
76: struct _child *c_next; /* Next entry */
77: };
78: typedef struct _child CHILD;
79:
80: static CHILD *childlist = NULL; /* List of children */
81: int activechildren = 0; /* Number of active children */
82: extern int maxchildren; /* Max active children */
83: static int needscan = FALSE; /* Need to scan children */
84:
85: /*
86: * Remove a child that has died (exited)
87: * from the list of active children
88: */
89: static void removechild(child)
90: CHILD *child;
91: {
92: register CHILD *pc, *prevpc;
93:
94: debugmsg(DM_CALL, "removechild(%s, %d, %d) start",
95: child->c_name, child->c_pid, child->c_readfd);
96:
97: /*
98: * Find the child in the list
99: */
100: for (pc = childlist, prevpc = NULL; pc != NULL;
101: prevpc = pc, pc = pc->c_next)
102: if (pc == child)
103: break;
104:
105: if (pc == NULL)
106: error("RemoveChild called with bad child %s %d %d",
107: child->c_name, child->c_pid, child->c_readfd);
108: else {
109: /*
110: * Remove the child
111: */
112: #if defined(POSIX_SIGNALS)
113: sigset_t set;
114:
115: sigemptyset(&set);
116: sigaddset(&set, SIGCHLD);
1.7 millert 117: sigprocmask(SIG_BLOCK, &set, NULL);
1.1 dm 118: #else /* !POSIX_SIGNALS */
119: int oldmask;
120:
121: oldmask = sigblock(sigmask(SIGCHLD));
122: #endif /* POSIX_SIGNALS */
123:
124: if (prevpc != NULL)
125: prevpc->c_next = pc->c_next;
126: else
127: childlist = pc->c_next;
128:
129: #if defined(POSIX_SIGNALS)
1.7 millert 130: sigprocmask(SIG_UNBLOCK, &set, NULL);
1.1 dm 131: #else
132: sigsetmask(oldmask);
133: #endif /* POSIX_SIGNALS */
134:
135: (void) free(child->c_name);
136: --activechildren;
137: (void) close(child->c_readfd);
138: (void) free(pc);
139: }
140:
141: debugmsg(DM_CALL, "removechild() end");
142: }
143:
144: /*
145: * Create a totally new copy of a child.
146: */
147: static CHILD *copychild(child)
148: CHILD *child;
149: {
150: register CHILD *newc;
151:
152: newc = (CHILD *) xmalloc(sizeof(CHILD));
153:
1.8 millert 154: newc->c_name = xstrdup(child->c_name);
1.1 dm 155: newc->c_readfd = child->c_readfd;
156: newc->c_pid = child->c_pid;
157: newc->c_state = child->c_state;
158: newc->c_next = NULL;
159:
160: return(newc);
161: }
162:
163: /*
164: * Add a child to the list of children.
165: */
166: static void addchild(child)
167: CHILD *child;
168: {
169: register CHILD *pc;
170:
171: debugmsg(DM_CALL, "addchild() start\n");
172:
173: pc = copychild(child);
174: pc->c_next = childlist;
175: childlist = pc;
176:
177: ++activechildren;
178:
179: debugmsg(DM_MISC,
180: "addchild() created '%s' pid %d fd %d (active=%d)\n",
181: child->c_name, child->c_pid, child->c_readfd, activechildren);
182: }
183:
184: /*
185: * Read input from a child process.
186: */
187: static void readchild(child)
188: CHILD *child;
189: {
190: char rbuf[BUFSIZ];
191: int amt;
192:
193: debugmsg(DM_CALL, "[readchild(%s, %d, %d) start]",
194: child->c_name, child->c_pid, child->c_readfd);
195:
196: /*
197: * Check that this is a valid child.
198: */
199: if (child->c_name == NULL || child->c_readfd <= 0) {
200: debugmsg(DM_MISC, "[readchild(%s, %d, %d) bad child]",
201: child->c_name, child->c_pid, child->c_readfd);
202: return;
203: }
204:
205: /*
206: * Read from child and display the result.
207: */
208: while ((amt = read(child->c_readfd, rbuf, sizeof(rbuf))) > 0) {
209: /* XXX remove these debug calls */
210: debugmsg(DM_MISC, "[readchild(%s, %d, %d) got %d bytes]",
211: child->c_name, child->c_pid, child->c_readfd, amt);
212:
213: (void) xwrite(fileno(stdout), rbuf, amt);
214:
215: debugmsg(DM_MISC, "[readchild(%s, %d, %d) write done]",
216: child->c_name, child->c_pid, child->c_readfd);
217: }
218:
219: debugmsg(DM_MISC, "readchild(%s, %d, %d) done: amt = %d errno = %d\n",
220: child->c_name, child->c_pid, child->c_readfd, amt, errno);
221:
222: /*
223: * See if we've reached EOF
224: */
225: if (amt == 0)
226: debugmsg(DM_MISC, "readchild(%s, %d, %d) at EOF\n",
227: child->c_name, child->c_pid, child->c_readfd);
228: }
229:
230: /*
231: * Wait for processes to exit. If "block" is true, then we block
232: * until a process exits. Otherwise, we return right away. If
233: * a process does exit, then the pointer "statval" is set to the
234: * exit status of the exiting process, if statval is not NULL.
235: */
236: static int waitproc(statval, block)
237: int *statval;
238: int block;
239: {
240: WAIT_ARG_TYPE status;
241: int pid, exitval;
242:
243: debugmsg(DM_CALL, "waitproc() %s, active children = %d...\n",
244: (block) ? "blocking" : "nonblocking", activechildren);
245:
246: #if WAIT_TYPE == WAIT_WAITPID
247: pid = waitpid(-1, &status, (block) ? 0 : WNOHANG);
248: #else
249: #if WAIT_TYPE == WAIT_WAIT3
250: pid = wait3(&status, (block) ? 0 : WNOHANG, NULL);
251: #endif /* WAIT_WAIT3 */
252: #endif /* WAIT_WAITPID */
253:
254: #if defined(WEXITSTATUS)
255: exitval = WEXITSTATUS(status);
256: #else
257: exitval = status.w_retcode;
258: #endif /* defined(WEXITSTATUS) */
259:
260: if (pid > 0 && exitval != 0) {
261: nerrs++;
262: debugmsg(DM_MISC,
263: "Child process %d exited with status %d.\n",
264: pid, exitval);
265: }
266:
267: if (statval)
268: *statval = exitval;
269:
270: debugmsg(DM_CALL, "waitproc() done (activechildren = %d)\n",
271: activechildren);
272:
273: return(pid);
274: }
275:
276: /*
277: * Check to see if any children have exited, and if so, read any unread
278: * input and then remove the child from the list of children.
279: */
280: static void reap()
281: {
282: register CHILD *pc;
1.5 deraadt 283: int save_errno = errno;
1.1 dm 284: int status = 0;
285: pid_t pid;
286:
287: debugmsg(DM_CALL, "reap() called\n");
288:
289: /*
290: * Reap every child that has exited. Break out of the
291: * loop as soon as we run out of children that have
292: * exited so far.
293: */
294: for ( ; ; ) {
295: /*
296: * Do a non-blocking check for exiting processes
297: */
298: pid = waitproc(&status, FALSE);
299: debugmsg(DM_MISC,
300: "reap() pid = %d status = %d activechildren=%d\n",
301: pid, status, activechildren);
302:
303: /*
304: * See if a child really exited
305: */
306: if (pid == 0)
307: break;
308: if (pid < 0) {
309: if (errno != ECHILD)
310: error("Wait failed: %s", SYSERR);
311: break;
312: }
313:
314: /*
315: * Find the process (pid) and mark it as dead.
316: */
317: for (pc = childlist; pc; pc = pc->c_next)
318: if (pc->c_pid == pid) {
319: needscan = TRUE;
320: pc->c_state = PSdead;
321: }
322:
323: }
324:
325: /*
326: * Reset signals
327: */
328: (void) signal(SIGCHLD, reap);
329:
330: debugmsg(DM_CALL, "reap() done\n");
1.5 deraadt 331: errno = save_errno;
1.1 dm 332: }
333:
334: /*
335: * Scan the children list to find the child that just exited,
336: * read any unread input, then remove it from the list of active children.
337: */
338: static void childscan()
339: {
340: register CHILD *pc, *nextpc;
341:
342: debugmsg(DM_CALL, "childscan() start");
343:
344: for (pc = childlist; pc; pc = nextpc) {
345: nextpc = pc->c_next;
346: if (pc->c_state == PSdead) {
347: readchild(pc);
348: removechild(pc);
349: }
350: }
351:
352: needscan = FALSE;
353: debugmsg(DM_CALL, "childscan() end");
354: }
355:
356: /*
357: #if defined HAVE_SELECT
358: *
359: * Wait for children to send output for us to read.
360: *
361: #else !HAVE_SELECT
362: *
363: * Wait up for children to exit.
364: *
365: #endif
366: */
367: extern void waitup()
368: {
369: #if defined(HAVE_SELECT)
370: register int count;
371: register CHILD *pc;
1.6 deraadt 372: fd_set *rchildfdsp = NULL;
373: int rchildfdsn = 0;
1.7 millert 374: size_t bytes;
1.1 dm 375:
376: debugmsg(DM_CALL, "waitup() start\n");
377:
378: if (needscan)
379: childscan();
380:
381: if (activechildren <= 0)
382: return;
383:
384: /*
385: * Settup which children we want to select() on.
386: */
1.6 deraadt 387: for (pc = childlist; pc; pc = pc->c_next)
388: if (pc->c_readfd > rchildfdsn)
389: rchildfdsn = pc->c_readfd;
390: bytes = howmany(rchildfdsn+1, NFDBITS) * sizeof(fd_mask);
391: if ((rchildfdsp = (fd_set *)malloc(bytes)) == NULL)
392: return;
393:
394: memset(rchildfdsp, 0, bytes);
1.1 dm 395: for (pc = childlist; pc; pc = pc->c_next)
396: if (pc->c_readfd > 0) {
397: debugmsg(DM_MISC, "waitup() select on %d (%s)\n",
398: pc->c_readfd, pc->c_name);
1.6 deraadt 399: FD_SET(pc->c_readfd, rchildfdsp);
1.1 dm 400: }
401:
402: /*
403: * Actually call select()
404: */
405: /* XXX remove debugmsg() calls */
406: debugmsg(DM_MISC, "waitup() Call select(), activechildren=%d\n",
407: activechildren);
408:
1.9 ! millert 409: count = select(rchildfdsn+1, (SELECT_FD_TYPE *) rchildfdsp,
1.7 millert 410: NULL, NULL, NULL);
1.1 dm 411:
412: debugmsg(DM_MISC, "waitup() select returned %d activechildren = %d\n",
413: count, activechildren);
414:
415: /*
416: * select() will return count < 0 and errno == EINTR when
417: * there are no active children left.
418: */
419: if (count < 0) {
420: if (errno != EINTR)
421: error("Select failed reading children input: %s",
422: SYSERR);
1.6 deraadt 423: free(rchildfdsp);
1.1 dm 424: return;
425: }
426:
427: /*
428: * This should never happen.
429: */
430: if (count == 0) {
431: error("Select returned an unexpected count of 0.");
1.6 deraadt 432: free(rchildfdsp);
1.1 dm 433: return;
434: }
435:
436: /*
437: * Go through the list of children and read from each child
438: * which select() detected as ready for reading.
439: */
440: for (pc = childlist; pc && count > 0; pc = pc->c_next) {
441: /*
442: * Make sure child still exists
443: */
444: if (pc->c_name && kill(pc->c_pid, 0) < 0 &&
445: errno == ESRCH) {
446: debugmsg(DM_MISC,
447: "waitup() proc %d (%s) died unexpectedly!",
448: pc->c_pid, pc->c_name);
449: pc->c_state = PSdead;
450: needscan = TRUE;
451: }
452:
453: if (pc->c_name == NULL ||
1.6 deraadt 454: !FD_ISSET(pc->c_readfd, rchildfdsp))
1.1 dm 455: continue;
456:
457: readchild(pc);
458: --count;
459: }
1.7 millert 460: free(rchildfdsp);
1.1 dm 461:
462: #else /* !defined(HAVE_SELECT) */
463:
464: /*
465: * The non-select() version of waitproc()
466: */
467: debugmsg(DM_CALL, "waitup() start\n");
468:
1.7 millert 469: if (waitproc(NULL, TRUE) > 0)
1.1 dm 470: --activechildren;
471:
472: #endif /* defined(HAVE_SELECT) */
473: debugmsg(DM_CALL, "waitup() end\n");
474: }
475:
476: /*
477: * Spawn (create) a new child process for "cmd".
478: */
479: extern int spawn(cmd, cmdlist)
480: struct cmd *cmd;
481: struct cmd *cmdlist;
482: {
483: pid_t pid;
484: int fildes[2];
485: char *childname = cmd->c_name;
486:
487: if (pipe(fildes) < 0) {
488: error("Cannot create pipe for %s: %s", childname, SYSERR);
489: return(-1);
490: }
491:
492: pid = fork();
493: if (pid == (pid_t)-1) {
494: error("Cannot spawn child for %s: fork failed: %s",
495: childname, SYSERR);
496: return(-1);
497: } else if (pid > 0) {
498: /*
499: * Parent
500: */
501: static CHILD newchild;
502:
503: #if defined(FORK_MISSES)
504: /*
505: * XXX Some OS's have a bug where fork does not
506: * always return properly to the parent
507: * when a number of forks are done very quicky.
508: */
509: sleep(2);
510: #endif /* FORK_MISSES */
511:
512: /* Receive notification when the child exits */
513: (void) signal(SIGCHLD, reap);
514:
515: /* Settup the new child */
516: newchild.c_next = NULL;
517: newchild.c_name = childname;
518: newchild.c_readfd = fildes[PIPE_READ];
519: newchild.c_pid = pid;
520: newchild.c_state = PSrunning;
521:
522: /* We're not going to write to the child */
523: (void) close(fildes[PIPE_WRITE]);
524:
525: /* Set non-blocking I/O */
526: if (setnonblocking(newchild.c_readfd, TRUE) < 0) {
527: error("Set nonblocking I/O failed: %s", SYSERR);
528: return(-1);
529: }
530:
531: /* Add new child to child list */
532: addchild(&newchild);
533:
534: /* Mark all other entries for this host as assigned */
535: markassigned(cmd, cmdlist);
536:
537: debugmsg(DM_CALL,
538: "spawn() Forked child %d for host %s active = %d\n",
539: pid, childname, activechildren);
540: return(pid);
541: } else {
542: /*
543: * Child
544: */
545:
546: /* We're not going to read from our parent */
547: (void) close(fildes[PIPE_READ]);
548:
549: /* Make stdout and stderr go to PIPE_WRITE (our parent) */
550: if (dup2(fildes[PIPE_WRITE], (int)fileno(stdout)) < 0) {
551: error("Cannot duplicate stdout file descriptor: %s",
552: SYSERR);
553: return(-1);
554: }
555: if (dup2(fildes[PIPE_WRITE], (int)fileno(stderr)) < 0) {
556: error("Cannot duplicate stderr file descriptor: %s",
557: SYSERR);
558: return(-1);
559: }
560:
561: return(0);
562: }
563: }
564:
565:
566: /*
567: * Enable or disable non-blocking I/O mode.
568: *
569: * Code is from INN by Rich Salz.
570: */
571: #if NBIO_TYPE == NBIO_IOCTL
572: #include <sys/ioctl.h>
573:
574: int setnonblocking(fd, flag)
575: int fd;
576: int flag;
577: {
578: int state;
579:
580: state = flag ? 1 : 0;
581: return(ioctl(fd, FIONBIO, (char *)&state));
582: }
583:
584: #endif /* NBIO_IOCTL */
585:
586:
587: #if NBIO_TYPE == NBIO_FCNTL
588: int setnonblocking(fd, flag)
589: int fd;
590: int flag;
591: {
592: int mode;
593:
594: if ((mode = fcntl(fd, F_GETFL, 0)) < 0)
595: return(-1);
596: if (flag)
597: mode |= FNDELAY;
598: else
599: mode &= ~FNDELAY;
600: return(fcntl(fd, F_SETFL, mode));
601: }
602: #endif /* NBIO_FCNTL */