/* $OpenBSD: newsyslog.c,v 1.47 2002/09/12 19:58:38 millert Exp $ */ /* * Copyright (c) 1999 Todd C. Miller * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. The name of the author may not be used to endorse or promote products * derived from this software without specific prior written permission. * * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY * AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL * THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */ /* * Copyright (c) 1997, Jason Downs. All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. All advertising materials mentioning features or use of this software * must display the following acknowledgement: * This product includes software developed by Jason Downs for the * OpenBSD system. * 4. Neither the name(s) of the author(s) nor the name OpenBSD * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE AUTHOR(S) ``AS IS'' AND ANY EXPRESS * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE * DISCLAIMED. IN NO EVENT SHALL THE AUTHOR(S) BE LIABLE FOR ANY DIRECT, * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. */ /* * This file contains changes from the Open Software Foundation. */ /* Copyright 1988, 1989 by the Massachusetts Institute of Technology Permission to use, copy, modify, and distribute this software and its documentation for any purpose and without fee is hereby granted, provided that the above copyright notice appear in all copies and that both that copyright notice and this permission notice appear in supporting documentation, and that the names of M.I.T. and the M.I.T. S.I.P.B. not be used in advertising or publicity pertaining to distribution of the software without specific, written prior permission. M.I.T. and the M.I.T. S.I.P.B. make no representations about the suitability of this software for any purpose. It is provided "as is" without express or implied warranty. */ /* * newsyslog - roll over selected logs at the appropriate time, * keeping the a specified number of backup files around. * */ #ifndef lint static char rcsid[] = "$OpenBSD: newsyslog.c,v 1.47 2002/09/12 19:58:38 millert Exp $"; #endif /* not lint */ #ifndef CONF #define CONF "/etc/newsyslog.conf" /* Configuration file */ #endif #ifndef PIDFILE #define PIDFILE "/etc/syslog.pid" #endif #ifndef COMPRESS #define COMPRESS "/usr/bin/compress" /* File compression program */ #endif #ifndef COMPRESS_POSTFIX #define COMPRESS_POSTFIX ".Z" #endif #ifndef STATS_DIR #define STATS_DIR "/etc" #endif #ifndef SENDMAIL #define SENDMAIL "/usr/lib/sendmail" #endif #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #define CE_ROTATED 0x01 /* Log file has been rotated */ #define CE_COMPACT 0x02 /* Compact the achived log files */ #define CE_BINARY 0x04 /* Logfile is in binary, don't add */ /* status messages */ #define CE_MONITOR 0x08 /* Monitory for changes */ #define CE_FOLLOW 0x10 /* Follow symbolic links */ #define NONE -1 struct conf_entry { char *log; /* Name of the log */ uid_t uid; /* Owner of log */ gid_t gid; /* Group of log */ int numlogs; /* Number of logs to keep */ int size; /* Size cutoff to trigger trimming the log */ int hours; /* Hours between log trimming */ int permissions; /* File permissions on the log */ int signal; /* Signal to send (defaults to SIGHUP) */ int flags; /* Flags (CE_COMPACT & CE_BINARY) */ char *whom; /* Whom to notify if logfile changes */ char *pidfile; /* Path to file containg pid to signal */ char *runcmd; /* Command to run instead of sending a signal */ struct conf_entry *next; /* Linked list pointer */ }; struct pidinfo { char *file; int signal; }; int verbose = 0; /* Print out what's going on */ int needroot = 1; /* Root privs are necessary */ int noaction = 0; /* Don't do anything, just show it */ int monitormode = 0; /* Don't do monitoring by default */ char *conf = CONF; /* Configuration file to use */ time_t timenow; #define MIN_PID 4 char hostname[MAXHOSTNAMELEN]; /* hostname */ char *daytime; /* timenow in human readable form */ void do_entry(struct conf_entry *); void PRS(int, char **); void usage(void); struct conf_entry *parse_file(int *); char *missing_field(char *, char *); void dotrim(char *, int, int, int, uid_t, gid_t); int log_trim(char *); void compress_log(char *); int sizefile(char *); int age_old_log(char *); char *sob(char *); char *son(char *); int isnumberstr(char *); void domonitor(char *, char *); FILE *openmail(void); void closemail(FILE *); void child_killer(int); void run_command(char *); void send_signal(char *, int); int main(argc, argv) int argc; char **argv; { struct conf_entry *p, *q; struct pidinfo *pidlist, *pl; int status, listlen; PRS(argc, argv); if (needroot && getuid() && geteuid()) errx(1, "You must be root."); p = q = parse_file(&listlen); signal(SIGCHLD, child_killer); pidlist = (struct pidinfo *)calloc(listlen + 1, sizeof(struct pidinfo)); if (pidlist == NULL) err(1, "calloc"); /* Step 1, rotate all log files */ while (q) { do_entry(q); q = q->next; } /* Step 2, make a list of unique pid files */ for (q = p, pl = pidlist; q; ) { if (q->flags & CE_ROTATED) { struct pidinfo *pltmp; for (pltmp = pidlist; pltmp < pl; pltmp++) { if ((strcmp(pltmp->file, q->pidfile) == 0 && pltmp->signal == q->signal) || (q->runcmd && strcmp(q->runcmd, pltmp->file) == 0)) break; } if (pltmp == pl) { /* unique entry */ if (q->runcmd) { pl->file = q->runcmd; pl->signal = -1; } else { pl->file = q->pidfile; pl->signal = q->signal; } pl++; } } q = q->next; } /* Step 3, send a signal or run a command */ for (pl = pidlist; pl->file; pl++) { if (pl->signal == -1) run_command(pl->file); else send_signal(pl->file, pl->signal); } if (!noaction) sleep(5); /* Step 4, compress the log.0 file if configured to do so and free */ while (p) { if ((p->flags & CE_COMPACT) && (p->flags & CE_ROTATED)) compress_log(p->log); q = p; p = p->next; free(q); } /* Wait for children to finish, then exit */ while (waitpid(-1, &status, 0) != -1) ; exit(0); } void do_entry(ent) struct conf_entry *ent; { int modtime, size; struct stat sta; if (!(ent->flags & CE_FOLLOW)) { if (lstat(ent->log, &sta) != 0) return; if ((sta.st_mode & S_IFLNK) != S_IFREG) { if (verbose) { printf("--> %s is not a regular file, skip\n", ent->log); return; } } } if (verbose) printf("%s <%d%s>: ", ent->log, ent->numlogs, (ent->flags & CE_COMPACT) ? "Z" : ""); size = sizefile(ent->log); modtime = age_old_log(ent->log); if (size < 0) { if (verbose) printf("does not exist.\n"); } else { if (verbose && (ent->size > 0)) printf("size (Kb): %d [%d] ", size, ent->size); if (verbose && (ent->hours > 0)) printf(" age (hr): %d [%d] ", modtime, ent->hours); if (monitormode && ent->flags & CE_MONITOR) domonitor(ent->log, ent->whom); if (!monitormode && (((ent->size > 0) && (size >= ent->size)) || ((ent->hours > 0) && ((modtime >= ent->hours) || (modtime < 0))))) { if (verbose) printf("--> trimming log....\n"); if (noaction && !verbose) printf("%s <%d%s>: ", ent->log, ent->numlogs, (ent->flags & CE_COMPACT) ? "Z" : ""); dotrim(ent->log, ent->numlogs, ent->flags, ent->permissions, ent->uid, ent->gid); ent->flags |= CE_ROTATED; } else if (verbose) printf("--> skipping\n"); } } /* Run the specified command */ void run_command(cmd) char *cmd; { if (noaction) (void)printf("run %s\n", cmd); else system(cmd); } /* Send a signal to the pid specified by pidfile */ void send_signal(pidfile, signal) char *pidfile; int signal; { char line[BUFSIZ]; pid_t pid = 0; FILE *f; unsigned long ulval; char *ep; char *err; if ((f = fopen(pidfile, "r")) == NULL) { warn("can't open %s", pidfile); return; } errno = 0; err = NULL; if (fgets(line, sizeof(line), f)) { ulval = strtoul(line, &ep, 10); if (line[0] == '\0' || (*ep != '\0' && *ep != '\n')) err = "invalid number in"; else if (errno == ERANGE && ulval == ULONG_MAX) err = "out of range number in"; else if (ulval == 0) err = "no number in"; else if (ulval < MIN_PID) err = "preposterous process number in"; else pid = ulval; } else { if (errno == 0) err = "empty"; else err = "error reading"; } (void)fclose(f); if (err) warnx("%s pid file: %s", err, pidfile); else if (noaction) (void)printf("kill -%s %ld\n", sys_signame[signal], (long)pid); else if (kill(pid, signal)) warnx("warning - could not send SIG%s to daemon", sys_signame[signal]); } void PRS(argc, argv) int argc; char **argv; { int c; char *p; timenow = time(NULL); daytime = ctime(&timenow) + 4; daytime[15] = '\0'; /* Let's get our hostname */ (void)gethostname(hostname, sizeof(hostname)); /* Truncate domain */ p = strchr(hostname, '.'); if (p) *p = '\0'; optind = 1; /* Start options parsing */ while ((c = getopt(argc, argv, "nrvmf:")) != -1) { switch (c) { case 'n': noaction++; /* This implies needroot as off */ /* fall through */ case 'r': needroot = 0; break; case 'v': verbose++; break; case 'f': conf = optarg; break; case 'm': monitormode++; break; default: usage(); } } } void usage() { extern const char *__progname; (void)fprintf(stderr, "usage: %s [-mnrv] [-f config_file]\n", __progname); exit(1); } /* Parse a configuration file and return a linked list of all the logs * to process */ struct conf_entry * parse_file(nentries) int *nentries; { FILE *f; char line[BUFSIZ], *parse, *q; char *errline, *group, *tmp; struct conf_entry *first = NULL; struct conf_entry *working = NULL; struct passwd *pass; struct group *grp; if (strcmp(conf, "-") == 0) f = stdin; else { if ((f = fopen(conf, "r")) == NULL) err(1, "can't open %s", conf); } *nentries = 0; while (fgets(line, sizeof(line), f)) { if ((line[0] == '\n') || (line[0] == '#')) continue; errline = strdup(line); if (errline == NULL) err(1, "strdup"); (*nentries)++; if (!first) { working = (struct conf_entry *) malloc(sizeof(struct conf_entry)); if (working == NULL) err(1, "malloc"); first = working; } else { working->next = (struct conf_entry *) malloc(sizeof(struct conf_entry)); if (working->next == NULL) err(1, "malloc"); working = working->next; } q = parse = missing_field(sob(line), errline); *(parse = son(line)) = '\0'; working->log = strdup(q); if (working->log == NULL) err(1, "strdup"); q = parse = missing_field(sob(++parse), errline); *(parse = son(parse)) = '\0'; if ((group = strchr(q, '.')) != NULL) { *group++ = '\0'; if (*q) { if (!(isnumberstr(q))) { if ((pass = getpwnam(q)) == NULL) errx(1, "Error in config file; unknown user: %s", q); working->uid = pass->pw_uid; } else working->uid = atoi(q); } else working->uid = NONE; q = group; if (*q) { if (!(isnumberstr(q))) { if ((grp = getgrnam(q)) == NULL) errx(1, "Error in config file; unknown group: %s", q); working->gid = grp->gr_gid; } else working->gid = atoi(q); } else working->gid = NONE; q = parse = missing_field(sob(++parse), errline); *(parse = son(parse)) = '\0'; } else working->uid = working->gid = NONE; if (!sscanf(q, "%o", &working->permissions)) errx(1, "Error in config file; bad permissions: %s", q); q = parse = missing_field(sob(++parse), errline); *(parse = son(parse)) = '\0'; if (!sscanf(q, "%d", &working->numlogs) || working->numlogs < 0) errx(1, "Error in config file; bad number: %s", q); q = parse = missing_field(sob(++parse), errline); *(parse = son(parse)) = '\0'; if (isdigit(*q)) working->size = atoi(q); else working->size = -1; q = parse = missing_field(sob(++parse), errline); *(parse = son(parse)) = '\0'; if (isdigit(*q)) working->hours = atoi(q); else working->hours = -1; working->flags = 0; q = sob(++parse); /* Optional field */ if (*q == 'Z' || *q == 'z' || *q == 'B' || *q == 'b' || *q == 'M' || *q == 'm') { *(parse = son(q)) = '\0'; while (*q) { switch (*q) { case 'Z': case 'z': working->flags |= CE_COMPACT; break; case 'B': case 'b': working->flags |= CE_BINARY; break; case 'M': case 'm': working->flags |= CE_MONITOR; break; case 'F': case 'f': working->flags |= CE_FOLLOW; break; default: errx(1, "Illegal flag in config file: %c", *q); break; } q++; } } else parse--; /* no flags so undo */ working->whom = NULL; if (working->flags & CE_MONITOR) { /* Optional field */ q = parse = sob(++parse); *(parse = son(parse)) = '\0'; working->whom = strdup(q); if (working->log == NULL) err(1, "strdup"); } working->pidfile = PIDFILE; working->signal = SIGHUP; working->runcmd = NULL; for (;;) { q = parse = sob(++parse); /* Optional field */ if (q == NULL || *q == '\0') break; if (*q == '/') { *(parse = son(parse)) = '\0'; if (strlen(q) >= MAXPATHLEN) errx(1, "%s: pathname too long", q); working->pidfile = strdup(q); if (working->pidfile == NULL) err(1, "strdup"); } else if (*q == '"' && (tmp = strchr(q + 1, '"'))) { *(parse = tmp) = '\0'; working->runcmd = strdup(++q); if (working->runcmd == NULL) err(1, "strdup"); } else if (strncmp(q, "SIG", 3) == 0) { int i; *(parse = son(parse)) = '\0'; for (i = 1; i < NSIG; i++) { if (!strcmp(sys_signame[i], q + 3)) { working->signal = i; break; } } if (i == NSIG) errx(1, "unknown signal: %s", q); } else errx(1, "unrecognized field: %s", q); } /* Make sure we can't oflow MAXPATHLEN */ if (asprintf(&tmp, "%s.%d%s", working->log, working->numlogs, COMPRESS_POSTFIX) >= MAXPATHLEN) errx(1, "%s: pathname too long", working->log); if (tmp) free(tmp); free(errline); } if (working) working->next = NULL; (void)fclose(f); return(first); } char * missing_field(p, errline) char *p; char *errline; { if (!p || !*p) { warnx("Missing field in config file line:"); fputs(errline, stderr); exit(1); } return(p); } void dotrim(log, numdays, flags, perm, owner_uid, group_gid) char *log; int numdays; int flags; int perm; uid_t owner_uid; gid_t group_gid; { char file1[MAXPATHLEN], file2[MAXPATHLEN]; char zfile1[MAXPATHLEN], zfile2[MAXPATHLEN]; int fd; struct stat st; int days = numdays; /* Remove oldest log (may not exist) */ (void)snprintf(file1, sizeof file1, "%s.%d", log, numdays); (void)snprintf(zfile1, sizeof zfile1, "%s.%d%s", log, numdays, COMPRESS_POSTFIX); if (noaction) { printf("rm -f %s %s\n", file1, zfile1); } else { (void)unlink(file1); (void)unlink(zfile1); } /* Move down log files */ while (numdays--) { (void)strlcpy(file2, file1, sizeof file2); (void)snprintf(file1, sizeof file1, "%s.%d", log, numdays); (void)strlcpy(zfile1, file1, sizeof zfile1); (void)strlcpy(zfile2, file2, sizeof zfile2); if (lstat(file1, &st)) { (void)strlcat(zfile1, COMPRESS_POSTFIX, sizeof zfile1); (void)strlcat(zfile2, COMPRESS_POSTFIX, sizeof zfile2); if (lstat(zfile1, &st)) continue; } if (noaction) { printf("mv %s %s\n", zfile1, zfile2); printf("chmod %o %s\n", perm, zfile2); printf("chown %u:%u %s\n", owner_uid, group_gid, zfile2); } else { if (rename(zfile1, zfile2)) warn("can't mv %s to %s", zfile1, zfile2); if (chmod(zfile2, perm)) warn("can't chmod %s", zfile2); if (chown(zfile2, owner_uid, group_gid)) warn("can't chown %s", zfile2); } } if (!noaction && !(flags & CE_BINARY)) (void)log_trim(log); /* Report the trimming to the old log */ (void)snprintf(file2, sizeof(file2), "%s.XXXXXXXXXX", log); if (noaction) { printf("Create new log file...\n"); } else { if ((fd = mkstemp(file2)) < 0) err(1, "can't start '%s' log", file2); if (fchown(fd, owner_uid, group_gid)) err(1, "can't chown '%s' log file", file2); if (fchmod(fd, perm)) err(1, "can't chmod '%s' log file", file2); (void)close(fd); /* Add status message */ if (!(flags & CE_BINARY) && log_trim(file2)) err(1, "can't add status message to log '%s'", file2); } if (days == 0) { if (noaction) printf("rm %s\n", log); else if (unlink(log)) warn("can't rm %s", log); } else { if (noaction) printf("mv %s to %s\n", log, file1); else if (rename(log, file1)) warn("can't to mv %s to %s", log, file1); } /* Now move the new log file into place */ if (noaction) printf("mv %s to %s\n", file2, log); else if (rename(file2, log)) warn("can't to mv %s to %s", file2, log); } /* Log the fact that the logs were turned over */ int log_trim(log) char *log; { FILE *f; if ((f = fopen(log, "a")) == NULL) return(-1); (void)fprintf(f, "%s %s newsyslog[%ld]: logfile turned over\n", daytime, hostname, (long)getpid()); if (fclose(f) == EOF) err(1, "log_trim: fclose"); return(0); } /* Fork off compress or gzip to compress the old log file */ void compress_log(log) char *log; { pid_t pid; char *base; char tmp[MAXPATHLEN]; if ((base = strrchr(COMPRESS, '/')) == NULL) base = COMPRESS; else base++; if (noaction) { printf("%s %s.0\n", base, log); return; } pid = fork(); (void)snprintf(tmp, sizeof tmp, "%s.0", log); if (pid < 0) { err(1, "fork"); } else if (!pid) { (void)execl(COMPRESS, base, "-f", tmp, (char *)NULL); warn(COMPRESS); _exit(1); } } /* Return size in kilobytes of a file */ int sizefile(file) char *file; { struct stat sb; if (stat(file, &sb) < 0) return(-1); return(sb.st_blocks / (1024.0 / DEV_BSIZE)); } /* Return the age (in hours) of old log file (file.0), or -1 if none */ int age_old_log(file) char *file; { struct stat sb; char tmp[MAXPATHLEN]; (void)strlcpy(tmp, file, sizeof tmp); strlcat(tmp, ".0", sizeof tmp); if (stat(tmp, &sb) < 0) { strlcat(tmp, COMPRESS_POSTFIX, sizeof tmp); if (stat(tmp, &sb) < 0) return(-1); } return( (int) (timenow - sb.st_mtime + 1800) / 3600); } /* Skip Over Blanks */ char * sob(p) char *p; { while (p && *p && isspace(*p)) p++; return(p); } /* Skip Over Non-Blanks */ char * son(p) char *p; { while (p && *p && !isspace(*p)) p++; return(p); } /* Check if string is actually a number */ int isnumberstr(string) char *string; { while (*string) { if (!isdigit(*string++)) return(0); } return(1); } void domonitor(log, whom) char *log, *whom; { struct stat sb, tsb; char fname[MAXPATHLEN], *flog, *p, *rb = NULL; FILE *fp; off_t osize; int rd; if (stat(log, &sb) < 0) return; flog = strdup(log); if (flog == NULL) err(1, "strdup"); for (p = flog; *p != '\0'; p++) { if (*p == '/') *p = '_'; } snprintf(fname, sizeof fname, "%s/newsyslog.%s.size", STATS_DIR, flog); /* ..if it doesn't exist, simply record the current size. */ if ((sb.st_size == 0) || stat(fname, &tsb) < 0) goto update; fp = fopen(fname, "r"); if (fp == NULL) { warn("%s", fname); goto cleanup; } #ifdef QUAD_OFF_T if (fscanf(fp, "%qd\n", &osize) != 1) { #else if (fscanf(fp, "%ld\n", &osize) != 1) { #endif /* QUAD_OFF_T */ fclose(fp); goto update; } fclose(fp); /* If the file is smaller, mark the entire thing as changed. */ if (sb.st_size < osize) osize = 0; /* Now see if current size is larger. */ if (sb.st_size > osize) { rb = (char *) malloc(sb.st_size - osize); if (rb == NULL) err(1, "malloc"); /* Open logfile, seek. */ fp = fopen(log, "r"); if (fp == NULL) { warn("%s", log); goto cleanup; } fseek(fp, osize, SEEK_SET); rd = fread(rb, 1, sb.st_size - osize, fp); if (rd < 1) { warn("fread"); fclose(fp); goto cleanup; } /* Send message. */ fclose(fp); fp = openmail(); if (fp == NULL) { warn("openmail"); goto cleanup; } fprintf(fp, "To: %s\nSubject: LOGFILE NOTIFICATION: %s\n\n\n", whom, log); fwrite(rb, 1, rd, fp); fputs("\n\n", fp); closemail(fp); } update: /* Reopen for writing and update file. */ fp = fopen(fname, "w"); if (fp == NULL) { warn("%s", fname); goto cleanup; } #ifdef QUAD_OFF_T fprintf(fp, "%qd\n", sb.st_size); #else fprintf(fp, "%ld\n", sb.st_size); #endif /* QUAD_OFF_T */ fclose(fp); cleanup: free(flog); if (rb != NULL) free(rb); } FILE * openmail() { char *cmdbuf = NULL; FILE *ret; asprintf(&cmdbuf, "%s -t", SENDMAIL); if (cmdbuf) { ret = popen(cmdbuf, "w"); free(cmdbuf); return (ret); } return (NULL); } void closemail(pfp) FILE *pfp; { pclose(pfp); } void child_killer(signum) int signum; { int save_errno = errno; int status; while (waitpid(-1, &status, WNOHANG) > 0) ; errno = save_errno; }