failtest: don't assume FD_SETSIZE is maximum runtime fd.

[ccan] / ccan / failtest / test / run-with-fdlimit.c

diff --git a/ccan/failtest/test/run-with-fdlimit.c b/ccan/failtest/test/run-with-fdlimit.c
new file mode 100644 (file)
index 0000000..6b4483f
--- /dev/null
+++ b/ccan/failtest/test/run-with-fdlimit.c
@@ -0,0 +1,51 @@
+/* Include the C files directly. */
+#include <ccan/failtest/failtest.c>
+#include <stdlib.h>
+#include <err.h>
+#include <ccan/tap/tap.h>
+
+int main(void)
+{
+       int fd, pfd[2], ecode;
+       struct rlimit lim;
+
+       if (getrlimit(RLIMIT_NOFILE, &lim) != 0)
+               err(1, "getrlimit RLIMIT_NOFILE fail?");
+
+       printf("rlimit = %lu/%lu (inf=%lu)\n",
+              (long)lim.rlim_cur, (long)lim.rlim_max,
+              (long)RLIM_INFINITY);
+       lim.rlim_cur /= 2;
+       if (lim.rlim_cur < 8)
+               errx(1, "getrlimit limit %li too low", (long)lim.rlim_cur);
+       if (setrlimit(RLIMIT_NOFILE, &lim) != 0)
+               err(1, "setrlimit RLIMIT_NOFILE (%li/%li)",
+                   (long)lim.rlim_cur, (long)lim.rlim_max);
+
+       plan_tests(2);
+       failtest_init(0, NULL);
+
+       if (pipe(pfd))
+               abort();
+
+       fd = failtest_open("run-with-fdlimit-scratch", "run-with_fdlimit.c", 1,
+                          O_RDWR|O_CREAT, 0600);
+       if (fd == -1) {
+               /* We are the child: write error code for parent to check. */
+               ecode = errno;
+               if (write(pfd[1], &ecode, sizeof(ecode)) != sizeof(ecode))
+                       abort();
+               failtest_exit(0);
+       }
+
+       /* Check child got correct errno. */
+       ok1(read(pfd[0], &ecode, sizeof(ecode)) == sizeof(ecode));
+       ok1(ecode == EACCES);
+
+       /* Clean up. */
+       failtest_close(fd, "run-open.c", 1);
+       close(pfd[0]);
+       close(pfd[1]);
+
+       return exit_status();
+}