fix select usage for high fd's (dynamically allocate readfds)

diff --git a/tgetpass.c b/tgetpass.c
index e91435cab9777cdef89517188c588140c47f1ce7..f8c950485a53a7cabd1ca12ed6e2d4817e161ab1 100644 (file)
--- a/tgetpass.c
+++ b/tgetpass.c
@@ -114,7 +114,7 @@ char * tgetpass(prompt, timeout, user, host)
     int n, echo;
     FILE *input, *output;
     static char buf[_PASSWD_LEN + 1];
-    fd_set readfds;
+    fd_set *readfds;
     struct timeval tv;
     char *p;
 
@@ -199,8 +199,14 @@ char * tgetpass(prompt, timeout, user, host)
      */
     if (timeout > 0) {
        /* setup for select(2) */
-       FD_ZERO(&readfds);
-       FD_SET(fileno(input), &readfds);
+       n = howmany(fileno(input) + 1, NFDBITS) * sizeof(fd_mask);
+       if ((readfds = (fd_set *) malloc(n)) == NULL) {
+           (void) fprintf(stderr, "Cannot allocate memory: ");
+           perror("");
+           return(NULL);
+       }
+       (void) memset((VOID *)readfds, 0, n);
+       FD_SET(fileno(input), readfds);
 
        /* set timeout for select */
        tv.tv_sec = timeout;
@@ -210,12 +216,13 @@ char * tgetpass(prompt, timeout, user, host)
         * get password or return empty string if nothing to read by timeout
         */
        buf[0] = '\0';
-       if (select(fileno(input) + 1, &readfds, 0, 0, &tv) > 0 &&
+       if (select(fileno(input) + 1, readfds, 0, 0, &tv) > 0 &&
            fgets(buf, sizeof(buf), input)) {
            n = strlen(buf);
            if (buf[n - 1] == '\n')
                buf[n - 1] = '\0';
        }
+       (void) free(readfds);
     } else {
        buf[0] = '\0';
        if (fgets(buf, sizeof(buf), input)) {