diff options
Diffstat (limited to 'images/hostoverlaytest/test.c')
-rw-r--r-- | images/hostoverlaytest/test.c | 88 |
1 files changed, 0 insertions, 88 deletions
diff --git a/images/hostoverlaytest/test.c b/images/hostoverlaytest/test.c deleted file mode 100644 index 088f90746..000000000 --- a/images/hostoverlaytest/test.c +++ /dev/null @@ -1,88 +0,0 @@ -#include <err.h> -#include <fcntl.h> -#include <stdio.h> -#include <string.h> -#include <sys/mman.h> -#include <unistd.h> - -int main(int argc, char** argv) { - const char kTestFilePath[] = "testfile.txt"; - const char kOldFileData[] = "old data\n"; - const char kNewFileData[] = "new data\n"; - const size_t kPageSize = sysconf(_SC_PAGE_SIZE); - - // Open a file that already exists in a host overlayfs lower layer. - const int fd_rdonly = open(kTestFilePath, O_RDONLY); - if (fd_rdonly < 0) { - err(1, "open(%s, O_RDONLY)", kTestFilePath); - } - - // Check that the file's initial contents are what we expect when read via - // syscall. - char oldbuf[sizeof(kOldFileData)] = {}; - ssize_t n = pread(fd_rdonly, oldbuf, sizeof(oldbuf), 0); - if (n < 0) { - err(1, "initial pread"); - } - if (n != strlen(kOldFileData)) { - errx(1, "short initial pread (%ld/%lu bytes)", n, strlen(kOldFileData)); - } - if (strcmp(oldbuf, kOldFileData) != 0) { - errx(1, "initial pread returned wrong data: %s", oldbuf); - } - - // Check that the file's initial contents are what we expect when read via - // memory mapping. - void* page = mmap(NULL, kPageSize, PROT_READ, MAP_SHARED, fd_rdonly, 0); - if (page == MAP_FAILED) { - err(1, "mmap"); - } - if (strcmp(page, kOldFileData) != 0) { - errx(1, "mapping contains wrong initial data: %s", (const char*)page); - } - - // Open the same file writably, causing host overlayfs to copy it up, and - // replace its contents. - const int fd_rdwr = open(kTestFilePath, O_RDWR); - if (fd_rdwr < 0) { - err(1, "open(%s, O_RDWR)", kTestFilePath); - } - n = write(fd_rdwr, kNewFileData, strlen(kNewFileData)); - if (n < 0) { - err(1, "write"); - } - if (n != strlen(kNewFileData)) { - errx(1, "short write (%ld/%lu bytes)", n, strlen(kNewFileData)); - } - if (ftruncate(fd_rdwr, strlen(kNewFileData)) < 0) { - err(1, "truncate"); - } - - int failed = 0; - - // Check that syscalls on the old FD return updated contents. (Before Linux - // 4.18, this requires that runsc use a post-copy-up FD to service the read.) - char newbuf[sizeof(kNewFileData)] = {}; - n = pread(fd_rdonly, newbuf, sizeof(newbuf), 0); - if (n < 0) { - err(1, "final pread"); - } - if (n != strlen(kNewFileData)) { - warnx("short final pread (%ld/%lu bytes)", n, strlen(kNewFileData)); - failed = 1; - } else if (strcmp(newbuf, kNewFileData) != 0) { - warnx("final pread returned wrong data: %s", newbuf); - failed = 1; - } - - // Check that the memory mapping of the old FD has been updated. (Linux - // overlayfs does not do this, so regardless of kernel version this requires - // that runsc replace existing memory mappings with mappings of a - // post-copy-up FD.) - if (strcmp(page, kNewFileData) != 0) { - warnx("mapping contains wrong final data: %s", (const char*)page); - failed = 1; - } - - return failed; -} |