[hackers] [scroll] set resource limit for scroll back buffer size || Jan Klemkow

[git]

commit b11c164c60aedf10026bfc1a168ce79ba005fe43
Author:     Jan Klemkow <j.klem...@wemelug.de>
AuthorDate: Thu Apr 9 20:29:27 2020 +0200
Commit:     Jan Klemkow <j.klem...@wemelug.de>
CommitDate: Thu Apr 9 20:44:57 2020 +0200

    set resource limit for scroll back buffer size

diff --git a/scroll.c b/scroll.c
index 51366f5..89bbd1d 100644
--- a/scroll.c
+++ b/scroll.c
@@ -21,6 +21,7 @@
 #include <sys/ioctl.h>
 #include <sys/wait.h>
 #include <sys/queue.h>
+#include <sys/resource.h>
 
 #include <assert.h>
 #include <errno.h>
@@ -333,9 +334,37 @@ jumpdown(char *buf, size_t size)
        scrolldown(buf, size, ws.ws_row);
 }
 
+void
+usage(void) {
+       die("usage: scroll [-M] [-m mem] <program>");
+}
+
 int
 main(int argc, char *argv[])
 {
+       int ch;
+       struct rlimit rlimit;
+
+       if (getrlimit(RLIMIT_DATA, &rlimit) == -1)
+               die("getrlimit");
+
+       while ((ch = getopt(argc, argv, "Mm:")) != -1) {
+               switch (ch) {
+               case 'M':
+                       rlimit.rlim_cur = rlimit.rlim_max;
+                       break;
+               case 'm':
+                       rlimit.rlim_cur = strtoull(optarg, NULL, 0);
+                       if (errno != 0)
+                               die("strtoull: %s", optarg);
+                       break;
+               default:
+                       usage();
+               }
+       }
+       argc -= optind;
+       argv += optind;
+
        TAILQ_INIT(&head);
 
        if (isatty(STDIN_FILENO) == 0)
@@ -343,8 +372,8 @@ main(int argc, char *argv[])
        if (isatty(STDOUT_FILENO) == 0)
                die("stdout it not a tty");
 
-       if (argc <= 1)
-               die("usage: scroll <program>");
+       if (argc < 1)
+               usage();
 
        /* save terminal settings for resetting after exit */
        if (tcgetattr(STDIN_FILENO, &dfl) == -1)
@@ -360,11 +389,15 @@ main(int argc, char *argv[])
        if (child == -1)
                die("forkpty:");
        if (child == 0) {       /* child */
-               execvp(argv[1], argv + 1);
+               execvp(argv[0], argv);
                perror("execvp");
                _exit(127);
        }
 
+       /* set maximum memory size for scrollback buffer */
+       if (setrlimit(RLIMIT_DATA, &rlimit) == -1)
+               die("setrlimit:");
+
 #ifdef __OpenBSD__
        if (pledge("stdio tty proc", NULL) == -1)
                die("pledge:");