+/*
+ * Execute a shell command to handle special cases.
+ */
+dospecial(cmd)
+ char *cmd;
+{
+ int fd[2], status, pid, i;
+ register char *cp, *s;
+ char sbuf[BUFSIZ];
+
+ if (pipe(fd) < 0) {
+ error("%s\n", sys_errlist[errno]);
+ return;
+ }
+ if ((pid = fork()) == 0) {
+ /*
+ * Return everything the shell commands print.
+ */
+ (void) close(0);
+ (void) close(1);
+ (void) close(2);
+ (void) open("/dev/null", 0);
+ (void) dup(fd[1]);
+ (void) dup(fd[1]);
+ (void) close(fd[0]);
+ (void) close(fd[1]);
+ execl("/bin/sh", "sh", "-c", cmd, 0);
+ _exit(127);
+ }
+ (void) close(fd[1]);
+ s = sbuf;
+ *s++ = '\0';
+ while ((i = read(fd[0], buf, sizeof(buf))) > 0) {
+ cp = buf;
+ do {
+ *s++ = *cp++;
+ if (cp[-1] != '\n') {
+ if (s < &sbuf[sizeof(sbuf)-1])
+ continue;
+ *s++ = '\n';
+ }
+ /*
+ * Throw away blank lines.
+ */
+ if (s == &sbuf[2]) {
+ s--;
+ continue;
+ }
+ (void) write(rem, sbuf, s - sbuf);
+ s = &sbuf[1];
+ } while (--i);
+ }
+ if (s > &sbuf[1]) {
+ *s++ = '\n';
+ (void) write(rem, sbuf, s - sbuf);
+ }
+ while ((i = wait(&status)) != pid && i != -1)
+ ;
+ if (i == -1)
+ status = -1;
+ if (status)
+ error("shell returned %d\n", status);
+ else
+ ack();
+}
+