basic: move acquire_data_fd() and fd_duplicate_data_fd() to new data-fd-util.c

fd_duplicate_data_fd() is renamed to copy_data_fd(). This makes
the two functions have nicely similar names.

Now fd-util.[ch] is again about low-level file descriptor manipulations.
copy_data_fd() is a complex function that internally wraps the other
functions in copy.c. I want to move copy.c and the whole cluster of
related code from basic/ to shared/ later on, and this is a preparatory
step for that.

1 files changed, 154 insertions, 0 deletions

diff --git a/src/test/test-data-fd-util.c b/src/test/test-data-fd-util.c
new file mode 100644
index 0000000000..22a57b5155
--- /dev/null
+++ b/src/test/test-data-fd-util.c
@@ -0,0 +1,154 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+
+#include "data-fd-util.h"
+#include "fd-util.h"
+#include "memory-util.h"
+#include "process-util.h"
+#include "tests.h"
+#include "random-util.h"
+
+static void test_acquire_data_fd_one(unsigned flags) {
+        char wbuffer[196*1024 - 7];
+        char rbuffer[sizeof(wbuffer)];
+        int fd;
+
+        fd = acquire_data_fd("foo", 3, flags);
+        assert_se(fd >= 0);
+
+        zero(rbuffer);
+        assert_se(read(fd, rbuffer, sizeof(rbuffer)) == 3);
+        assert_se(streq(rbuffer, "foo"));
+
+        fd = safe_close(fd);
+
+        fd = acquire_data_fd("", 0, flags);
+        assert_se(fd >= 0);
+
+        zero(rbuffer);
+        assert_se(read(fd, rbuffer, sizeof(rbuffer)) == 0);
+        assert_se(streq(rbuffer, ""));
+
+        fd = safe_close(fd);
+
+        random_bytes(wbuffer, sizeof(wbuffer));
+
+        fd = acquire_data_fd(wbuffer, sizeof(wbuffer), flags);
+        assert_se(fd >= 0);
+
+        zero(rbuffer);
+        assert_se(read(fd, rbuffer, sizeof(rbuffer)) == sizeof(rbuffer));
+        assert_se(memcmp(rbuffer, wbuffer, sizeof(rbuffer)) == 0);
+
+        fd = safe_close(fd);
+}
+
+static void test_acquire_data_fd(void) {
+        test_acquire_data_fd_one(0);
+        test_acquire_data_fd_one(ACQUIRE_NO_DEV_NULL);
+        test_acquire_data_fd_one(ACQUIRE_NO_MEMFD);
+        test_acquire_data_fd_one(ACQUIRE_NO_DEV_NULL|ACQUIRE_NO_MEMFD);
+        test_acquire_data_fd_one(ACQUIRE_NO_PIPE);
+        test_acquire_data_fd_one(ACQUIRE_NO_DEV_NULL|ACQUIRE_NO_PIPE);
+        test_acquire_data_fd_one(ACQUIRE_NO_MEMFD|ACQUIRE_NO_PIPE);
+        test_acquire_data_fd_one(ACQUIRE_NO_DEV_NULL|ACQUIRE_NO_MEMFD|ACQUIRE_NO_PIPE);
+        test_acquire_data_fd_one(ACQUIRE_NO_DEV_NULL|ACQUIRE_NO_MEMFD|ACQUIRE_NO_PIPE|ACQUIRE_NO_TMPFILE);
+}
+
+static void assert_equal_fd(int fd1, int fd2) {
+        for (;;) {
+                uint8_t a[4096], b[4096];
+                ssize_t x, y;
+
+                x = read(fd1, a, sizeof(a));
+                assert_se(x >= 0);
+
+                y = read(fd2, b, sizeof(b));
+                assert_se(y >= 0);
+
+                assert_se(x == y);
+
+                if (x == 0)
+                        break;
+
+                assert_se(memcmp(a, b, x) == 0);
+        }
+}
+
+static void test_copy_data_fd(void) {
+        _cleanup_close_ int fd1 = -1, fd2 = -1;
+        _cleanup_(close_pairp) int sfd[2] = { -1, -1 };
+        _cleanup_(sigkill_waitp) pid_t pid = -1;
+        int r;
+
+        fd1 = open("/etc/fstab", O_RDONLY|O_CLOEXEC);
+        if (fd1 >= 0) {
+
+                fd2 = copy_data_fd(fd1);
+                assert_se(fd2 >= 0);
+
+                assert_se(lseek(fd1, 0, SEEK_SET) == 0);
+                assert_equal_fd(fd1, fd2);
+        }
+
+        fd1 = safe_close(fd1);
+        fd2 = safe_close(fd2);
+
+        fd1 = acquire_data_fd("hallo", 6,  0);
+        assert_se(fd1 >= 0);
+
+        fd2 = copy_data_fd(fd1);
+        assert_se(fd2 >= 0);
+
+        safe_close(fd1);
+        fd1 = acquire_data_fd("hallo", 6,  0);
+        assert_se(fd1 >= 0);
+
+        assert_equal_fd(fd1, fd2);
+
+        fd1 = safe_close(fd1);
+        fd2 = safe_close(fd2);
+
+        assert_se(socketpair(AF_UNIX, SOCK_STREAM|SOCK_CLOEXEC, 0, sfd) >= 0);
+
+        r = safe_fork("(sd-pipe)", FORK_RESET_SIGNALS|FORK_DEATHSIG|FORK_LOG, &pid);
+        assert_se(r >= 0);
+
+        if (r == 0) {
+                /* child */
+
+                sfd[0] = safe_close(sfd[0]);
+
+                for (uint64_t i = 0; i < 1536*1024 / sizeof(uint64_t); i++)
+                        assert_se(write(sfd[1], &i, sizeof(i)) == sizeof(i));
+
+                sfd[1] = safe_close(sfd[1]);
+
+                _exit(EXIT_SUCCESS);
+        }
+
+        sfd[1] = safe_close(sfd[1]);
+
+        fd2 = copy_data_fd(sfd[0]);
+        assert_se(fd2 >= 0);
+
+        uint64_t j;
+        for (uint64_t i = 0; i < 1536*1024 / sizeof(uint64_t); i++) {
+                assert_se(read(fd2, &j, sizeof(j)) == sizeof(j));
+                assert_se(i == j);
+        }
+
+        assert_se(read(fd2, &j, sizeof(j)) == 0);
+}
+
+int main(int argc, char *argv[]) {
+        test_setup_logging(LOG_DEBUG);
+
+        test_acquire_data_fd();
+        test_copy_data_fd();
+
+        return 0;
+}