New

diff --git a/bin/setrlimit.c b/bin/setrlimit.c
new file mode 100644 (file)
index 0000000..17c579d
--- /dev/null
+++ b/bin/setrlimit.c
@@ -0,0 +1,96 @@
+/* $Id: setrlimit.c,v 1.1 2007-02-27 14:52:55 mike Exp $ */
+
+/*
+ * A simple wrapper program for the setrlimit(2) system call, which
+ * can be used to run a subprocess under a different regime -- much
+ * like "nice", "time", etc.  This is needed for IRSpy, since when it
+ * runs against many servers simultaneously, it runs out of file
+ * descriptors -- a condition, by the way, which Perl sometimes
+ * reports very misleadingly (e.g. "Can't locate Scalar/Util.pm in
+ * @INC" when the open() failure was due to EMFILE rather than
+ * ENOENT).
+ *
+ * Since the file-descriptor limit can only be raised (from the
+ * default of 1024 in Ubuntu) by root, this program often needs to run
+ * as root -- hence the option for resetting the UID after performing
+ * the limit-change.
+ */
+
+#include <getopt.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <errno.h>
+#include <string.h>
+#include <sys/time.h>
+#include <sys/resource.h>
+#include <sys/types.h>
+#include <unistd.h>
+#include <pwd.h>
+
+int main(int argc, char **argv) {
+    int n = 0;
+    char *user = 0;
+    int c;
+
+    while ((c = getopt(argc, argv, "n:u:")) != -1) {
+       switch (c) {
+       case 'n': n = atoi(optarg); break;
+       case 'u': user = optarg; break;
+       default:
+       USAGE:
+           fprintf(stderr, "Usage: %s [options] <command>\n\
+       -n <number>     Set maximum open files to <number>\n\
+       -u <user>       Run subcommand as <user>\n",
+                   argv[0]);
+           exit(1);
+       }
+    }
+
+    if (optind == argc)
+       goto USAGE;
+
+    if (n != 0) {
+       struct rlimit old, new;
+       getrlimit(RLIMIT_NOFILE, &old);
+       new = old;
+       new.rlim_cur = n;
+       if (n > new.rlim_max)
+           new.rlim_max = n;
+#if 0
+       if (new.rlim_cur != old.rlim_cur)
+           printf("%s: changing soft NOFILE from %ld to %ld\n",
+                  argv[0], (long) old.rlim_cur, (long) new.rlim_cur);
+       if (new.rlim_max != old.rlim_max)
+           printf("%s: changing soft NOFILE from %ld to %ld\n",
+                  argv[0], (long) old.rlim_max, (long) new.rlim_max);
+#endif
+       if (setrlimit(RLIMIT_NOFILE, &new) < 0) {
+           fprintf(stderr, "%s: setrlimit(n=%d): %s\n",
+                   argv[0], n, strerror(errno));
+           exit(2);
+       }
+    }
+
+    if (user != 0) {
+       struct passwd *pwd;
+       if ((pwd = getpwnam(user)) == 0) {
+           fprintf(stderr, "%s: user '%s' not known\n", argv[0], user);
+           exit(3);
+       }
+
+       if (setuid(pwd->pw_uid) < 0) {
+           fprintf(stderr, "%s: setuid('%s'=%ld): %s\n",
+                   argv[0], user, (long) pwd->pw_uid, strerror(errno));
+           exit(4);
+       }
+    }
+
+#if 0
+    printf("%s: n=%d, user='%s', optind=%d, new argc=%d, new argv[0]='%s'\n",
+          argv[0], n, user, optind, argc-optind, argv[optind]);
+#endif
+    execvp(argv[optind], argv+optind);
+    fprintf(stderr, "%s: execvp('%s'): %s\n",
+           argv[0], argv[optind], strerror(errno));
+    exit(5);
+}