bus: update test-bus-memfd

src/libsystemd-bus/test-bus-memfd.c

@@ -33,6 +33,9 @@ int main(int argc, char *argv[]) {
         uint64_t sz;
         int r, fd;
         FILE *f;
+        char buf[3] = {};
+        struct iovec iov[3] = {};
+        char bufv[3][3] = {};
 
         log_set_max_level(LOG_DEBUG);
 
@@ -49,12 +52,20 @@ int main(int argc, char *argv[]) {
         assert_se(r == -EPERM);
 
         assert_se(write(sd_memfd_get_fd(m), "he", 2) == 2);
+        assert_se(write(sd_memfd_get_fd(m), "XXX", 3) == 3);
+        assert_se(streq(s, "heXXX world"));
+
+        /* fix "hello" */
+        assert_se(lseek(sd_memfd_get_fd(m), 2, SEEK_SET) == 2);
         assert_se(write(sd_memfd_get_fd(m), "ll", 2) == 2);
 
         assert_se(sd_memfd_get_file(m, &f) >= 0);
         fputc('o', f);
         fflush(f);
 
+        /* check content  */
+        assert_se(streq(s, "hello world"));
+
         assert_se(munmap(s, 12) == 0);
 
         r = sd_memfd_get_sealed(m);
@@ -64,9 +75,15 @@ int main(int argc, char *argv[]) {
         assert_se(r >= 0);
         assert_se(sz = page_size());
 
-        r = sd_memfd_set_size(m, 12);
+        /* truncate it */
+        r = sd_memfd_set_size(m, 6);
         assert_se(r >= 0);
 
+        /* get back new value */
+        r = sd_memfd_get_size(m, &sz);
+        assert_se(r >= 0);
+        assert_se(sz == 6);
+
         r = sd_memfd_set_sealed(m, 1);
         assert_se(r >= 0);
 
@@ -78,27 +95,79 @@ int main(int argc, char *argv[]) {
 
         sd_memfd_free(m);
 
+        /* new sd_memfd, same underlying memfd */
         r = sd_memfd_make(fd, &m);
         assert_se(r >= 0);
 
+        /* we did truncate it to 6 */
         r = sd_memfd_get_size(m, &sz);
-        assert_se(r >= 0);
-        assert_se(sz = 12);
+        assert_se(sz == 6);
 
-        r = sd_memfd_map(m, 0, 12, (void**) &s);
+        /* map it, check content */
+        r = sd_memfd_map(m, 0, 12, (void **)&s);
         assert_se(r >= 0);
 
+        /* we only see the truncated size */
+        assert_se(streq(s, "hello "));
+
+        /* it was already sealed */
         r = sd_memfd_set_sealed(m, 1);
         assert_se(r == -EALREADY);
 
+        /* we cannot break the seal, it is mapped */
         r = sd_memfd_set_sealed(m, 0);
         assert_se(r == -EPERM);
 
-        assert_se(streq(s, "hello world"));
+        /* unmap it; become the single owner */
         assert_se(munmap(s, 12) == 0);
 
+        /* now we can do flip the sealing */
         r = sd_memfd_set_sealed(m, 0);
-        assert_se(r >= 0);
+        assert_se(r == 0);
+        r = sd_memfd_get_sealed(m);
+        assert_se(r == 0);
+
+        r = sd_memfd_set_sealed(m, 1);
+        assert_se(r == 0);
+        r = sd_memfd_get_sealed(m);
+        assert_se(r == 1);
+
+        r = sd_memfd_set_sealed(m, 0);
+        assert_se(r == 0);
+        r = sd_memfd_get_sealed(m);
+        assert_se(r == 0);
+
+        /* seek at 2, read() 2 bytes */
+        assert_se(lseek(fd, 2, SEEK_SET) == 2);
+        assert_se(read(fd, buf, 2) == 2);
+
+        /* check content */
+        assert_se(memcmp(buf, "ll", 2) == 0);
+
+        /* writev it out*/
+        iov[0].iov_base = (char *)"ABC";
+        iov[0].iov_len = 3;
+        iov[1].iov_base = (char *)"DEF";
+        iov[1].iov_len = 3;
+        iov[2].iov_base = (char *)"GHI";
+        iov[2].iov_len = 3;
+        assert_se(lseek(fd, 0, SEEK_SET) == 0);
+        assert_se(writev(fd, iov, 3) == 9);
+
+        /* readv it back */
+        iov[0].iov_base = bufv[0];
+        iov[0].iov_len = 3;
+        iov[1].iov_base = bufv[1];
+        iov[1].iov_len = 3;
+        iov[2].iov_base = bufv[2];
+        iov[2].iov_len = 3;
+        assert_se(lseek(fd, 0, SEEK_SET) == 0);
+        assert_se(readv(fd, iov, 3) == 9);
+
+        /* check content */
+        assert_se(memcmp(bufv[0], "ABC", 3) == 0);
+        assert_se(memcmp(bufv[1], "DEF", 3) == 0);
+        assert_se(memcmp(bufv[2], "GHI", 3) == 0);
 
         sd_memfd_free(m);