// SPDX-License-Identifier: GPL-2.0 #define _GNU_SOURCE #define __SANE_USERSPACE_TYPES__ // Use ll64 #include #include #include #include #include #include #include #include #include #include #include #include "../../kselftest.h" #include "log.h" #include "../wrappers.h" static long get_file_dev_and_inode(void *addr, struct statx *stx) { char buf[4096]; FILE *mapf; mapf = fopen("/proc/self/maps", "r"); if (mapf == NULL) return pr_perror("fopen(/proc/self/maps)"); while (fgets(buf, sizeof(buf), mapf)) { unsigned long start, end; uint32_t maj, min; __u64 ino; if (sscanf(buf, "%lx-%lx %*s %*s %x:%x %llu", &start, &end, &maj, &min, &ino) != 5) return pr_perror("unable to parse: %s", buf); if (start == (unsigned long)addr) { stx->stx_dev_major = maj; stx->stx_dev_minor = min; stx->stx_ino = ino; return 0; } } return pr_err("unable to find the mapping"); } static int ovl_mount(void) { int tmpfs, fsfd, ovl; fsfd = sys_fsopen("tmpfs", 0); if (fsfd == -1) return pr_perror("fsopen(tmpfs)"); if (sys_fsconfig(fsfd, FSCONFIG_CMD_CREATE, NULL, NULL, 0) == -1) return pr_perror("FSCONFIG_CMD_CREATE"); tmpfs = sys_fsmount(fsfd, 0, 0); if (tmpfs == -1) return pr_perror("fsmount"); close(fsfd); /* overlayfs can't be constructed on top of a detached mount. */ if (sys_move_mount(tmpfs, "", AT_FDCWD, "/tmp", MOVE_MOUNT_F_EMPTY_PATH)) return pr_perror("move_mount"); close(tmpfs); if (mkdir("/tmp/w", 0755) == -1 || mkdir("/tmp/u", 0755) == -1 || mkdir("/tmp/l", 0755) == -1) return pr_perror("mkdir"); fsfd = sys_fsopen("overlay", 0); if (fsfd == -1) return pr_perror("fsopen(overlay)"); if (sys_fsconfig(fsfd, FSCONFIG_SET_STRING, "source", "test", 0) == -1 || sys_fsconfig(fsfd, FSCONFIG_SET_STRING, "lowerdir", "/tmp/l", 0) == -1 || sys_fsconfig(fsfd, FSCONFIG_SET_STRING, "upperdir", "/tmp/u", 0) == -1 || sys_fsconfig(fsfd, FSCONFIG_SET_STRING, "workdir", "/tmp/w", 0) == -1) return pr_perror("fsconfig"); if (sys_fsconfig(fsfd, FSCONFIG_CMD_CREATE, NULL, NULL, 0) == -1) return pr_perror("fsconfig"); ovl = sys_fsmount(fsfd, 0, 0); if (ovl == -1) return pr_perror("fsmount"); return ovl; } /* * Check that the file device and inode shown in /proc/pid/maps match values * returned by stat(2). */ static int test(void) { struct statx stx, mstx; int ovl, fd; void *addr; ovl = ovl_mount(); if (ovl == -1) return -1; fd = openat(ovl, "test", O_RDWR | O_CREAT, 0644); if (fd == -1) return pr_perror("openat"); addr = mmap(NULL, 4096, PROT_READ | PROT_WRITE, MAP_FILE | MAP_SHARED, fd, 0); if (addr == MAP_FAILED) return pr_perror("mmap"); if (get_file_dev_and_inode(addr, &mstx)) return -1; if (statx(fd, "", AT_EMPTY_PATH | AT_STATX_SYNC_AS_STAT, STATX_INO, &stx)) return pr_perror("statx"); if (stx.stx_dev_major != mstx.stx_dev_major || stx.stx_dev_minor != mstx.stx_dev_minor || stx.stx_ino != mstx.stx_ino) return pr_fail("unmatched dev:ino %x:%x:%llx (expected %x:%x:%llx)\n", mstx.stx_dev_major, mstx.stx_dev_minor, mstx.stx_ino, stx.stx_dev_major, stx.stx_dev_minor, stx.stx_ino); ksft_test_result_pass("devices are matched\n"); return 0; } int main(int argc, char **argv) { int fsfd; fsfd = sys_fsopen("overlay", 0); if (fsfd == -1) { ksft_test_result_skip("unable to create overlay mount\n"); return 1; } close(fsfd); /* Create a new mount namespace to not care about cleaning test mounts. */ if (unshare(CLONE_NEWNS) == -1) { ksft_test_result_skip("unable to create a new mount namespace\n"); return 1; } if (sys_mount(NULL, "/", NULL, MS_SLAVE | MS_REC, NULL) == -1) { pr_perror("mount"); return 1; } ksft_set_plan(1); if (test()) return 1; ksft_exit_pass(); return 0; }