1 files changed, 152 insertions, 0 deletions
diff --git a/src/shared/pcrextend-util.c b/src/shared/pcrextend-util.c
new file mode 100644
index 0000000..fa066a4
--- /dev/null
+++ b/src/shared/pcrextend-util.c
@@ -0,0 +1,152 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include "sd-device.h"
+
+#include "blkid-util.h"
+#include "blockdev-util.h"
+#include "chase.h"
+#include "errno-util.h"
+#include "escape.h"
+#include "fd-util.h"
+#include "mountpoint-util.h"
+#include "pcrextend-util.h"
+#include "strv.h"
+
+static int device_get_file_system_word(
+                sd_device *d,
+                const char *prefix,
+                char **ret) {
+
+#if HAVE_BLKID
+        int r;
+#endif
+
+        assert(d);
+        assert(prefix);
+        assert(ret);
+
+#if HAVE_BLKID
+        _cleanup_close_ int block_fd = sd_device_open(d, O_RDONLY|O_CLOEXEC|O_NONBLOCK);
+        if (block_fd < 0)
+                return block_fd;
+
+        _cleanup_(blkid_free_probep) blkid_probe b = blkid_new_probe();
+        if (!b)
+                return -ENOMEM;
+
+        errno = 0;
+        r = blkid_probe_set_device(b, block_fd, 0, 0);
+        if (r != 0)
+                return errno_or_else(ENOMEM);
+
+        (void) blkid_probe_enable_superblocks(b, 1);
+        (void) blkid_probe_set_superblocks_flags(b, BLKID_SUBLKS_TYPE|BLKID_SUBLKS_UUID|BLKID_SUBLKS_LABEL);
+        (void) blkid_probe_enable_partitions(b, 1);
+        (void) blkid_probe_set_partitions_flags(b, BLKID_PARTS_ENTRY_DETAILS);
+
+        errno = 0;
+        r = blkid_do_safeprobe(b);
+        if (r == _BLKID_SAFEPROBE_ERROR)
+                return errno_or_else(EIO);
+        if (IN_SET(r, _BLKID_SAFEPROBE_AMBIGUOUS, _BLKID_SAFEPROBE_NOT_FOUND))
+                return -ENOPKG;
+
+        assert(r == _BLKID_SAFEPROBE_FOUND);
+
+        _cleanup_strv_free_ char **l = strv_new(prefix);
+        if (!l)
+                return -ENOMEM;
+
+        FOREACH_STRING(field, "TYPE", "UUID", "LABEL", "PART_ENTRY_UUID", "PART_ENTRY_TYPE", "PART_ENTRY_NAME") {
+                const char *v = NULL;
+
+                (void) blkid_probe_lookup_value(b, field, &v, NULL);
+
+                _cleanup_free_ char *escaped = xescape(strempty(v), ":"); /* Avoid ambiguity around ":" */
+                if (!escaped)
+                        return -ENOMEM;
+
+                r = strv_consume(&l, TAKE_PTR(escaped));
+                if (r < 0)
+                        return r;
+        }
+
+        assert(strv_length(l) == 7); /* We always want 7 components, to avoid ambiguous strings */
+
+        _cleanup_free_ char *word = strv_join(l, ":");
+        if (!word)
+                return -ENOMEM;
+
+        *ret = TAKE_PTR(word);
+        return 0;
+#else
+        return -EOPNOTSUPP;
+#endif
+}
+
+int pcrextend_file_system_word(const char *path, char **ret_word, char **ret_normalized_path) {
+        _cleanup_free_ char *normalized_path = NULL, *normalized_escaped = NULL, *prefix = NULL, *word = NULL;
+        _cleanup_(sd_device_unrefp) sd_device *d = NULL;
+        _cleanup_close_ int dfd = -EBADF;
+        int r;
+
+        assert(path);
+        assert(ret_word);
+
+        dfd = chase_and_open(path, NULL, 0, O_DIRECTORY|O_CLOEXEC, &normalized_path);
+        if (dfd < 0)
+                return log_error_errno(dfd, "Failed to open path '%s': %m", path);
+
+        r = fd_is_mount_point(dfd, NULL, 0);
+        if (r < 0)
+                return log_error_errno(r, "Failed to determine if path '%s' is mount point: %m", normalized_path);
+        if (r == 0)
+                return log_error_errno(SYNTHETIC_ERRNO(ENOTDIR), "Specified path '%s' is not a mount point, refusing: %m", normalized_path);
+
+        normalized_escaped = xescape(normalized_path, ":"); /* Avoid ambiguity around ":" */
+        if (!normalized_escaped)
+                return log_oom();
+
+        prefix = strjoin("file-system:", normalized_escaped);
+        if (!prefix)
+                return log_oom();
+
+        r = block_device_new_from_fd(dfd, BLOCK_DEVICE_LOOKUP_BACKING, &d);
+        if (r < 0) {
+                log_notice_errno(r, "Unable to determine backing block device of '%s', using generic fallback file system identity string: %m", path);
+
+                word = strjoin(prefix, "::::::");
+                if (!word)
+                        return log_oom();
+        } else {
+                r = device_get_file_system_word(d, prefix, &word);
+                if (r < 0)
+                        return log_error_errno(r, "Failed to get file system identifier string for '%s': %m", path);
+        }
+
+        *ret_word = TAKE_PTR(word);
+
+        if (ret_normalized_path)
+                *ret_normalized_path = TAKE_PTR(normalized_path);
+
+        return 0;
+}
+
+int pcrextend_machine_id_word(char **ret) {
+        _cleanup_free_ char *word = NULL;
+        sd_id128_t mid;
+        int r;
+
+        assert(ret);
+
+        r = sd_id128_get_machine(&mid);
+        if (r < 0)
+                return log_error_errno(r, "Failed to acquire machine ID: %m");
+
+        word = strjoin("machine-id:", SD_ID128_TO_STRING(mid));
+        if (!word)
+                return log_oom();
+
+        *ret = TAKE_PTR(word);
+        return 0;
+}