diff options
| -rw-r--r-- | init/initramfs_test.c | 67 |
1 files changed, 66 insertions, 1 deletions
diff --git a/init/initramfs_test.c b/init/initramfs_test.c index 517e5e04e5cc..5d2db455e60c 100644 --- a/init/initramfs_test.c +++ b/init/initramfs_test.c @@ -45,8 +45,11 @@ static size_t fill_cpio(struct initramfs_test_cpio *cs, size_t csz, char *out) c->mtime, c->filesize, c->devmajor, c->devminor, c->rdevmajor, c->rdevminor, c->namesize, c->csum, c->fname) + 1; + pr_debug("packing (%zu): %.*s\n", thislen, (int)thislen, pos); - off += thislen; + if (thislen != CPIO_HDRLEN + c->namesize) + pr_debug("padded to: %u\n", CPIO_HDRLEN + c->namesize); + off += CPIO_HDRLEN + c->namesize; while (off & 3) out[off++] = '\0'; @@ -384,6 +387,67 @@ static void __init initramfs_test_many(struct kunit *test) } /* + * An initramfs filename is namesize in length, including the zero-terminator. + * A filename can be zero-terminated prior to namesize, with the remainder used + * as padding. This can be useful for e.g. alignment of file data segments with + * a 4KB filesystem block, allowing for extent sharing (reflinks) between cpio + * source and destination. This hack works with both GNU cpio and initramfs, as + * long as PATH_MAX isn't exceeded. + */ +static void __init initramfs_test_fname_pad(struct kunit *test) +{ + char *err; + size_t len; + struct file *file; + char fdata[] = "this file data is aligned at 4K in the archive"; + struct test_fname_pad { + char padded_fname[4096 - CPIO_HDRLEN]; + char cpio_srcbuf[CPIO_HDRLEN + PATH_MAX + 3 + sizeof(fdata)]; + } *tbufs = kzalloc(sizeof(struct test_fname_pad), GFP_KERNEL); + struct initramfs_test_cpio c[] = { { + .magic = "070701", + .ino = 1, + .mode = S_IFREG | 0777, + .uid = 0, + .gid = 0, + .nlink = 1, + .mtime = 1, + .filesize = sizeof(fdata), + .devmajor = 0, + .devminor = 1, + .rdevmajor = 0, + .rdevminor = 0, + /* align file data at 4K archive offset via padded fname */ + .namesize = 4096 - CPIO_HDRLEN, + .csum = 0, + .fname = tbufs->padded_fname, + .data = fdata, + } }; + + memcpy(tbufs->padded_fname, "padded_fname", sizeof("padded_fname")); + len = fill_cpio(c, ARRAY_SIZE(c), tbufs->cpio_srcbuf); + + err = unpack_to_rootfs(tbufs->cpio_srcbuf, len); + KUNIT_EXPECT_NULL(test, err); + + file = filp_open(c[0].fname, O_RDONLY, 0); + if (IS_ERR(file)) { + KUNIT_FAIL(test, "open failed"); + goto out; + } + + /* read back file contents into @cpio_srcbuf and confirm match */ + len = kernel_read(file, tbufs->cpio_srcbuf, c[0].filesize, NULL); + KUNIT_EXPECT_EQ(test, len, c[0].filesize); + KUNIT_EXPECT_MEMEQ(test, tbufs->cpio_srcbuf, c[0].data, len); + + fput(file); + KUNIT_EXPECT_EQ(test, init_unlink(c[0].fname), 0); +out: + kfree(tbufs); +} + +/* * The kunit_case/_suite struct cannot be marked as __initdata as this will be * used in debugfs to retrieve results after test has run. */ @@ -394,6 +458,7 @@ static struct kunit_case __refdata initramfs_test_cases[] = { KUNIT_CASE(initramfs_test_csum), KUNIT_CASE(initramfs_test_hardlink), KUNIT_CASE(initramfs_test_many), + KUNIT_CASE(initramfs_test_fname_pad), {}, }; |