+ errno = EINVAL;
+ if (stat(prog, &sbuf) < 0 || !S_ISREG(sbuf.st_mode)
+ || (sbuf.st_mode & (S_IXUSR|S_IXGRP|S_IXOTH)) == 0) {
+ if (must_exist || errno != ENOENT)
+ warn("Can't execute %s: %m", prog);
+ return 0;
+ }
+
+ pid = fork();
+ if (pid == -1) {
+ error("Failed to create child process for %s: %m", prog);
+ return -1;
+ }
+ if (pid == 0) {
+ int new_fd;
+
+ /* Leave the current location */
+ (void) setsid(); /* No controlling tty. */
+ (void) umask (S_IRWXG|S_IRWXO);
+ (void) chdir ("/"); /* no current directory. */
+ setuid(0); /* set real UID = root */
+ setgid(getegid());
+
+ /* Ensure that nothing of our device environment is inherited. */
+ sys_close();
+ closelog();
+ close (0);
+ close (1);
+ close (2);
+ close (ttyfd); /* tty interface to the ppp device */
+ if (real_ttyfd >= 0)
+ close(real_ttyfd);
+
+ /* Don't pass handles to the PPP device, even by accident. */
+ new_fd = open (_PATH_DEVNULL, O_RDWR);
+ if (new_fd >= 0) {
+ if (new_fd != 0) {
+ dup2 (new_fd, 0); /* stdin <- /dev/null */
+ close (new_fd);
+ }
+ dup2 (0, 1); /* stdout -> /dev/null */
+ dup2 (0, 2); /* stderr -> /dev/null */
+ }
+
+#ifdef BSD
+ /* Force the priority back to zero if pppd is running higher. */
+ if (setpriority (PRIO_PROCESS, 0, 0) < 0)
+ warn("can't reset priority to 0: %m");
+#endif
+
+ /* SysV recommends a second fork at this point. */
+
+ /* run the program */
+ execve(prog, args, script_env);
+ if (must_exist || errno != ENOENT) {
+ /* have to reopen the log, there's nowhere else
+ for the message to go. */
+ reopen_log();
+ syslog(LOG_ERR, "Can't execute %s: %m", prog);
+ closelog();
+ }
+ _exit(-1);
+ }
+
+ if (debug)
+ dbglog("Script %s started; pid = %d", prog, pid);
+ record_child(pid, prog, done, arg);
+
+ return pid;
+}
+
+
+/*
+ * record_child - add a child process to the list for reap_kids
+ * to use.
+ */
+static void
+record_child(pid, prog, done, arg)
+ int pid;
+ char *prog;
+ void (*done) __P((void *));
+ void *arg;
+{
+ struct subprocess *chp;
+
+ ++n_children;
+
+ chp = (struct subprocess *) malloc(sizeof(struct subprocess));
+ if (chp == NULL) {
+ warn("losing track of %s process", prog);
+ } else {
+ chp->pid = pid;
+ chp->prog = prog;
+ chp->done = done;
+ chp->arg = arg;
+ chp->next = children;
+ children = chp;
+ }
+}
+
+
+/*
+ * reap_kids - get status from any dead child processes,
+ * and log a message for abnormal terminations.
+ */
+static void
+reap_kids(waitfor)
+ int waitfor;
+{
+ int pid, status;
+ struct subprocess *chp, **prevp;
+
+ got_sigchld = 0;
+ if (n_children == 0)
+ return;
+ while ((pid = waitpid(-1, &status, (waitfor? 0: WNOHANG))) != -1
+ && pid != 0) {
+ --n_children;
+ for (prevp = &children; (chp = *prevp) != NULL; prevp = &chp->next)
+ if (chp->pid == pid)
+ break;
+ if (WIFSIGNALED(status)) {
+ warn("Child process %s (pid %d) terminated with signal %d",
+ (chp? chp->prog: "??"), pid, WTERMSIG(status));
+ } else if (debug)
+ dbglog("Script %s finished (pid %d), status = 0x%x",
+ (chp? chp->prog: "??"), pid, status);
+ if (chp && chp->done)
+ (*chp->done)(chp->arg);
+ }
+ if (pid == -1 && errno != ECHILD && errno != EINTR)
+ error("Error waiting for child process: %m");
+}
+
+
+/*
+ * log_packet - format a packet and log it.
+ */
+
+char line[256]; /* line to be logged accumulated here */
+char *linep;
+
+void
+log_packet(p, len, prefix, level)
+ u_char *p;
+ int len;
+ char *prefix;
+ int level;
+{
+ strlcpy(line, prefix, sizeof(line));
+ linep = line + strlen(line);
+ format_packet(p, len, pr_log, NULL);
+ if (linep != line)
+ syslog(level, "%s", line);
+}
+
+/*
+ * format_packet - make a readable representation of a packet,
+ * calling `printer(arg, format, ...)' to output it.
+ */
+static void
+format_packet(p, len, printer, arg)
+ u_char *p;
+ int len;
+ void (*printer) __P((void *, char *, ...));
+ void *arg;
+{
+ int i, n;
+ u_short proto;
+ struct protent *protp;
+
+ if (len >= PPP_HDRLEN && p[0] == PPP_ALLSTATIONS && p[1] == PPP_UI) {
+ p += 2;
+ GETSHORT(proto, p);
+ len -= PPP_HDRLEN;
+ for (i = 0; (protp = protocols[i]) != NULL; ++i)
+ if (proto == protp->protocol)
+ break;
+ if (protp != NULL) {
+ printer(arg, "[%s", protp->name);
+ n = (*protp->printpkt)(p, len, printer, arg);
+ printer(arg, "]");
+ p += n;
+ len -= n;
+ } else {
+ for (i = 0; (protp = protocols[i]) != NULL; ++i)
+ if (proto == (protp->protocol & ~0x8000))
+ break;
+ if (protp != 0 && protp->data_name != 0) {
+ printer(arg, "[%s data]", protp->data_name);
+ if (len > 8)
+ printer(arg, "%.8B ...", p);
+ else
+ printer(arg, "%.*B", len, p);
+ len = 0;
+ } else
+ printer(arg, "[proto=0x%x]", proto);
+ }
+ }
+
+ if (len > 32)
+ printer(arg, "%.32B ...", p);
+ else
+ printer(arg, "%.*B", len, p);
+}
+
+static void
+pr_log __V((void *arg, char *fmt, ...))
+{
+ int n;
+ va_list pvar;
+ char buf[256];
+
+#if __STDC__
+ va_start(pvar, fmt);
+#else
+ void *arg;
+ char *fmt;
+ va_start(pvar);
+ arg = va_arg(pvar, void *);
+ fmt = va_arg(pvar, char *);
+#endif
+
+ n = vslprintf(buf, sizeof(buf), fmt, pvar);
+ va_end(pvar);
+
+ if (linep + n + 1 > line + sizeof(line)) {
+ syslog(LOG_DEBUG, "%s", line);
+ linep = line;
+ }
+ strlcpy(linep, buf, line + sizeof(line) - linep);
+ linep += n;
+}
+
+/*
+ * vslp_printer - used in processing a %P format
+ */
+struct buffer_info {
+ char *ptr;
+ int len;
+};
+
+static void
+vslp_printer __V((void *arg, char *fmt, ...))
+{
+ int n;
+ va_list pvar;
+ struct buffer_info *bi;
+
+#if __STDC__
+ va_start(pvar, fmt);
+#else
+ void *arg;
+ char *fmt;
+ va_start(pvar);
+ arg = va_arg(pvar, void *);
+ fmt = va_arg(pvar, char *);
+#endif
+
+ bi = (struct buffer_info *) arg;
+ n = vslprintf(bi->ptr, bi->len, fmt, pvar);
+ va_end(pvar);
+
+ bi->ptr += n;
+ bi->len -= n;
+}
+
+/*
+ * print_string - print a readable representation of a string using
+ * printer.
+ */
+void
+print_string(p, len, printer, arg)
+ char *p;
+ int len;
+ void (*printer) __P((void *, char *, ...));
+ void *arg;
+{
+ int c;
+
+ printer(arg, "\"");
+ for (; len > 0; --len) {
+ c = *p++;
+ if (' ' <= c && c <= '~') {
+ if (c == '\\' || c == '"')
+ printer(arg, "\\");
+ printer(arg, "%c", c);
+ } else {
+ switch (c) {
+ case '\n':
+ printer(arg, "\\n");
+ break;
+ case '\r':
+ printer(arg, "\\r");
+ break;
+ case '\t':
+ printer(arg, "\\t");
+ break;
+ default:
+ printer(arg, "\\%.3o", c);
+ }
+ }
+ }
+ printer(arg, "\"");
+}
+
+/*
+ * novm - log an error message saying we ran out of memory, and die.
+ */
+void
+novm(msg)
+ char *msg;
+{
+ fatal("Virtual memory exhausted allocating %s\n", msg);
+}
+
+/*
+ * slprintf - format a message into a buffer. Like sprintf except we
+ * also specify the length of the output buffer, and we handle
+ * %r (recursive format), %m (error message), %v (visible string),
+ * %q (quoted string), %t (current time) and %I (IP address) formats.
+ * Doesn't do floating-point formats.
+ * Returns the number of chars put into buf.
+ */
+int
+slprintf __V((char *buf, int buflen, char *fmt, ...))
+{
+ va_list args;
+ int n;
+
+#if __STDC__
+ va_start(args, fmt);
+#else
+ char *buf;
+ int buflen;
+ char *fmt;
+ va_start(args);
+ buf = va_arg(args, char *);
+ buflen = va_arg(args, int);
+ fmt = va_arg(args, char *);
+#endif
+ n = vslprintf(buf, buflen, fmt, args);
+ va_end(args);
+ return n;
+}
+
+/*
+ * vslprintf - like slprintf, takes a va_list instead of a list of args.
+ */
+#define OUTCHAR(c) (buflen > 0? (--buflen, *buf++ = (c)): 0)
+
+int
+vslprintf(buf, buflen, fmt, args)
+ char *buf;
+ int buflen;
+ char *fmt;
+ va_list args;
+{
+ int c, i, n;
+ int width, prec, fillch;
+ int base, len, neg, quoted;
+ unsigned long val = 0;
+ char *str, *f, *buf0;
+ unsigned char *p;
+ char num[32];
+ time_t t;
+ u_int32_t ip;
+ static char hexchars[] = "0123456789abcdef";
+ struct buffer_info bufinfo;
+
+ buf0 = buf;
+ --buflen;
+ while (buflen > 0) {
+ for (f = fmt; *f != '%' && *f != 0; ++f)
+ ;
+ if (f > fmt) {
+ len = f - fmt;
+ if (len > buflen)
+ len = buflen;
+ memcpy(buf, fmt, len);
+ buf += len;
+ buflen -= len;
+ fmt = f;
+ }
+ if (*fmt == 0)
+ break;
+ c = *++fmt;
+ width = prec = 0;
+ fillch = ' ';
+ if (c == '0') {
+ fillch = '0';
+ c = *++fmt;
+ }
+ if (c == '*') {
+ width = va_arg(args, int);
+ c = *++fmt;
+ } else {
+ while (isdigit(c)) {
+ width = width * 10 + c - '0';
+ c = *++fmt;
+ }
+ }
+ if (c == '.') {
+ c = *++fmt;
+ if (c == '*') {
+ prec = va_arg(args, int);
+ c = *++fmt;
+ } else {
+ while (isdigit(c)) {
+ prec = prec * 10 + c - '0';
+ c = *++fmt;
+ }
+ }
+ }
+ str = 0;
+ base = 0;
+ neg = 0;
+ ++fmt;
+ switch (c) {
+ case 'd':
+ i = va_arg(args, int);
+ if (i < 0) {
+ neg = 1;
+ val = -i;
+ } else
+ val = i;
+ base = 10;
+ break;
+ case 'o':
+ val = va_arg(args, unsigned int);
+ base = 8;
+ break;
+ case 'x':
+ case 'X':
+ val = va_arg(args, unsigned int);
+ base = 16;
+ break;
+ case 'p':
+ val = (unsigned long) va_arg(args, void *);
+ base = 16;
+ neg = 2;
+ break;
+ case 's':
+ str = va_arg(args, char *);
+ break;
+ case 'c':
+ num[0] = va_arg(args, int);
+ num[1] = 0;
+ str = num;
+ break;
+ case 'm':
+ str = strerror(errno);
+ break;
+ case 'I':
+ ip = va_arg(args, u_int32_t);
+ ip = ntohl(ip);
+ slprintf(num, sizeof(num), "%d.%d.%d.%d", (ip >> 24) & 0xff,
+ (ip >> 16) & 0xff, (ip >> 8) & 0xff, ip & 0xff);
+ str = num;
+ break;
+ case 'r':
+ f = va_arg(args, char *);
+#ifndef __powerpc__
+ n = vslprintf(buf, buflen + 1, f, va_arg(args, va_list));
+#else
+ /* On the powerpc, a va_list is an array of 1 structure */
+ n = vslprintf(buf, buflen + 1, f, va_arg(args, void *));
+#endif
+ buf += n;
+ buflen -= n;
+ continue;
+ case 't':
+ time(&t);
+ str = ctime(&t);
+ str += 4; /* chop off the day name */
+ str[15] = 0; /* chop off year and newline */
+ break;
+ case 'v': /* "visible" string */
+ case 'q': /* quoted string */
+ quoted = c == 'q';
+ p = va_arg(args, unsigned char *);
+ if (fillch == '0' && prec > 0) {
+ n = prec;
+ } else {
+ n = strlen((char *)p);
+ if (prec > 0 && prec < n)
+ n = prec;
+ }
+ while (n > 0 && buflen > 0) {
+ c = *p++;
+ --n;
+ if (!quoted && c >= 0x80) {
+ OUTCHAR('M');
+ OUTCHAR('-');
+ c -= 0x80;
+ }
+ if (quoted && (c == '"' || c == '\\'))
+ OUTCHAR('\\');
+ if (c < 0x20 || (0x7f <= c && c < 0xa0)) {
+ if (quoted) {
+ OUTCHAR('\\');
+ switch (c) {
+ case '\t': OUTCHAR('t'); break;
+ case '\n': OUTCHAR('n'); break;
+ case '\b': OUTCHAR('b'); break;
+ case '\f': OUTCHAR('f'); break;
+ default:
+ OUTCHAR('x');
+ OUTCHAR(hexchars[c >> 4]);
+ OUTCHAR(hexchars[c & 0xf]);
+ }
+ } else {
+ if (c == '\t')
+ OUTCHAR(c);
+ else {
+ OUTCHAR('^');
+ OUTCHAR(c ^ 0x40);
+ }
+ }
+ } else
+ OUTCHAR(c);
+ }
+ continue;
+ case 'P': /* print PPP packet */
+ bufinfo.ptr = buf;
+ bufinfo.len = buflen + 1;
+ p = va_arg(args, unsigned char *);
+ n = va_arg(args, int);
+ format_packet(p, n, vslp_printer, &bufinfo);
+ buf = bufinfo.ptr;
+ buflen = bufinfo.len - 1;
+ continue;
+ case 'B':
+ p = va_arg(args, unsigned char *);
+ for (n = prec; n > 0; --n) {
+ c = *p++;
+ if (fillch == ' ')
+ OUTCHAR(' ');
+ OUTCHAR(hexchars[(c >> 4) & 0xf]);
+ OUTCHAR(hexchars[c & 0xf]);
+ }
+ continue;
+ default:
+ *buf++ = '%';
+ if (c != '%')
+ --fmt; /* so %z outputs %z etc. */
+ --buflen;
+ continue;
+ }
+ if (base != 0) {
+ str = num + sizeof(num);
+ *--str = 0;
+ while (str > num + neg) {
+ *--str = hexchars[val % base];
+ val = val / base;
+ if (--prec <= 0 && val == 0)
+ break;
+ }
+ switch (neg) {
+ case 1:
+ *--str = '-';
+ break;
+ case 2:
+ *--str = 'x';
+ *--str = '0';
+ break;
+ }
+ len = num + sizeof(num) - 1 - str;
+ } else {
+ len = strlen(str);
+ if (prec > 0 && len > prec)
+ len = prec;