zdtm: Add fd01 test

Fork tasks and create fds with different numbers.
Some children share file with parent (CLONE_FILES).
Check, than we can suspend and resume in this case.

v2: New
Signed-off-by: Kirill Tkhai <ktkhai@virtuozzo.com>
Signed-off-by: Andrei Vagin <avagin@virtuozzo.com>

test/zdtm/static/Makefile

@@ -173,6 +173,7 @@ TST_NOFILE	:=				\
 		aio00				\
 		aio01				\
 		fd				\
+		fd01				\
 		apparmor				\
 		seccomp_strict			\
 		seccomp_filter			\

test/zdtm/static/fd01.c

+#include <sys/types.h>
+#include <sys/mman.h>
+#include <sys/stat.h>
+#include <sys/time.h>
+#include <sys/resource.h>
+#include <fcntl.h>
+#include <errno.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/wait.h>
+#include <sched.h>
+
+#include "zdtmtst.h"
+#include "lock.h"
+
+const char *test_doc	= "Create file descriptors with different numbers. Check that they do not intersect with service fds";
+const char *test_author	= "Kirill Tkhai <ktkhai@virtuozzo.com>";
+
+int main(int argc, char **argv)
+{
+	unsigned int i, max_nr, flags;
+	int fd, status, ret;
+	struct rlimit rlim;
+	char buf[16];
+	pid_t pid;
+
+	test_init(argc, argv);
+
+	fd = open("/proc/sys/fs/nr_open", O_RDONLY);
+	if (fd < 0) {
+		fail("Can't open /proc/sys/fs/nr_open");
+		exit(1);
+	}
+
+	ret = read(fd, buf, sizeof(buf));
+	if (ret <= 0) {
+		fail("Can't read");
+		exit(1);
+	}
+	buf[ret] = '\0';
+
+	max_nr = (unsigned int)atol(buf);
+	if (max_nr == 0) {
+		fail("max_nr");
+		exit(1);
+	}
+
+	if (getrlimit(RLIMIT_NOFILE, &rlim)) {
+		fail("getrlimit");
+		exit(1);
+	}
+
+	rlim.rlim_cur = rlim.rlim_max;
+	if (max_nr < rlim.rlim_cur)
+		rlim.rlim_cur = max_nr;
+
+	if (prlimit(getpid(), RLIMIT_NOFILE, &rlim, NULL)) {
+		fail("rlimir: Can't setup RLIMIT_NOFILE for self");
+		exit(1);
+	}
+
+
+	for (i = 1; (fd = (1 << i)) < (rlim.rlim_cur >> 1); i++) {
+		FILE *fp = tmpfile();
+		if (!fp) {
+			fail("tmpfile");
+			exit(1);
+		}
+
+		/* This fd really exists, skip it */
+		if (fcntl(fd, F_GETFL) >= 0)
+			continue;
+
+		if (dup2(fileno(fp), fd) < 0) {
+			fail("dup2");
+			exit(1);
+		}
+
+		flags = SIGCHLD;
+		if (i % 2 == 0)
+			flags |= CLONE_FILES;
+
+		pid = sys_clone_unified(flags, NULL, NULL, NULL, 0);
+		if (pid < 0) {
+			fail("fork");
+			exit(1);
+		} else if (!pid) {
+			pause();
+			exit(0);
+		}
+	}
+
+	test_daemon();
+	test_waitsig();
+
+	/* Cleanup */
+	while ((pid = waitpid(-1, &status, WNOHANG)) > 0) {
+		if (kill(pid, SIGTERM) == 0)
+			waitpid(-1, &status, 0); /* Ignore errors */
+	}
+
+	pass();
+
+	return 0;
+}

test/zdtm/static/fd01.desc

+{'flags': 'suid'}