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authorDavid Oberhollenzer <david.oberhollenzer@sigma-star.at>2020-04-27 20:19:46 +0200
committerDavid Oberhollenzer <david.oberhollenzer@sigma-star.at>2020-04-27 20:41:21 +0200
commit687e44297071c95004d47e389fc409b951a8f9ff (patch)
tree6383b32c960a32bfb1393b774cc72a54fe2b94b1 /bin/gensquashfs/dirscan_xattr.c
parent6a0d2f053ba32c63bb9a3c40135f8d5bb46c9cb0 (diff)
Cleanup/fix: gensquashfs: split directory scanning from xattr scanning
On the one hand, this commit cleanes the code a bit by splitting the "scan directory contents" code from the "scan xattrs from directory contents" and moving the later in a seperate file. On the other hand, the xattr scanning is now done *after* the fstree is post processed, which includes sorting it. This way, the xattrs are always added in a deterministic, reproducible order. Signed-off-by: David Oberhollenzer <david.oberhollenzer@sigma-star.at>
Diffstat (limited to 'bin/gensquashfs/dirscan_xattr.c')
-rw-r--r--bin/gensquashfs/dirscan_xattr.c200
1 files changed, 200 insertions, 0 deletions
diff --git a/bin/gensquashfs/dirscan_xattr.c b/bin/gensquashfs/dirscan_xattr.c
new file mode 100644
index 0000000..3995a19
--- /dev/null
+++ b/bin/gensquashfs/dirscan_xattr.c
@@ -0,0 +1,200 @@
+/* SPDX-License-Identifier: GPL-3.0-or-later */
+/*
+ * dirscan_xattr.c
+ *
+ * Copyright (C) 2019 David Oberhollenzer <goliath@infraroot.at>
+ */
+#include "mkfs.h"
+
+#ifdef HAVE_SYS_XATTR_H
+static char *get_full_path(const char *prefix, tree_node_t *node)
+{
+ char *path = NULL, *new = NULL;
+ size_t path_len, prefix_len;
+ int ret;
+
+ path = fstree_get_path(node);
+ if (path == NULL)
+ goto fail;
+
+ ret = canonicalize_name(path);
+ assert(ret == 0);
+
+ path_len = strlen(path);
+ prefix_len = strlen(prefix);
+
+ while (prefix_len > 0 && prefix[prefix_len - 1] == '/')
+ --prefix_len;
+
+ if (prefix_len > 0) {
+ new = realloc(path, path_len + prefix_len + 2);
+ if (new == NULL)
+ goto fail;
+
+ path = new;
+
+ memmove(path + prefix_len + 1, path, path_len + 1);
+ memcpy(path, prefix, prefix_len);
+ path[prefix_len] = '/';
+ }
+
+ return path;
+fail:
+ perror("getting full path for xattr scan");
+ free(path);
+ return NULL;
+}
+
+static int xattr_from_path(sqfs_xattr_writer_t *xwr, const char *path)
+{
+ char *key, *value = NULL, *buffer = NULL;
+ ssize_t buflen, vallen, keylen;
+ int ret;
+
+ buflen = llistxattr(path, NULL, 0);
+ if (buflen < 0) {
+ fprintf(stderr, "llistxattr %s: %s", path, strerror(errno));
+ return -1;
+ }
+
+ if (buflen == 0)
+ return 0;
+
+ buffer = malloc(buflen);
+ if (buffer == NULL) {
+ perror("xattr name buffer");
+ return -1;
+ }
+
+ buflen = llistxattr(path, buffer, buflen);
+ if (buflen == -1) {
+ fprintf(stderr, "llistxattr %s: %s", path, strerror(errno));
+ goto fail;
+ }
+
+ key = buffer;
+ while (buflen > 0) {
+ vallen = lgetxattr(path, key, NULL, 0);
+ if (vallen == -1) {
+ fprintf(stderr, "lgetxattr %s: %s",
+ path, strerror(errno));
+ goto fail;
+ }
+
+ if (vallen > 0) {
+ value = calloc(1, vallen);
+ if (value == NULL) {
+ perror("allocating xattr value buffer");
+ goto fail;
+ }
+
+ vallen = lgetxattr(path, key, value, vallen);
+ if (vallen == -1) {
+ fprintf(stderr, "lgetxattr %s: %s\n",
+ path, strerror(errno));
+ goto fail;
+ }
+
+ ret = sqfs_xattr_writer_add(xwr, key, value, vallen);
+ if (ret) {
+ sqfs_perror(path,
+ "storing xattr key-value pairs",
+ ret);
+ goto fail;
+ }
+
+ free(value);
+ value = NULL;
+ }
+
+ keylen = strlen(key) + 1;
+ buflen -= keylen;
+ key += keylen;
+ }
+
+ free(buffer);
+ return 0;
+fail:
+ free(value);
+ free(buffer);
+ return -1;
+}
+#endif
+
+static int xattr_xcan_dfs(const char *path_prefix, void *selinux_handle,
+ sqfs_xattr_writer_t *xwr, unsigned int flags,
+ tree_node_t *node)
+{
+ char *path;
+ int ret;
+
+ ret = sqfs_xattr_writer_begin(xwr);
+ if (ret) {
+ sqfs_perror(node->name, "recoding xattr key-value pairs\n",
+ ret);
+ return -1;
+ }
+
+#ifdef HAVE_SYS_XATTR_H
+ if (flags & DIR_SCAN_READ_XATTR) {
+ path = get_full_path(path_prefix, node);
+ if (path == NULL)
+ return -1;
+
+ ret = xattr_from_path(xwr, path);
+ free(path);
+
+ if (ret)
+ return -1;
+ }
+#else
+ (void)path_prefix;
+#endif
+
+ if (selinux_handle != NULL) {
+ path = fstree_get_path(node);
+ if (path == NULL) {
+ perror("reconstructing absolute path");
+ return -1;
+ }
+
+ ret = selinux_relable_node(selinux_handle, xwr, node, path);
+ free(path);
+
+ if (ret)
+ return -1;
+ }
+
+ if (sqfs_xattr_writer_end(xwr, &node->xattr_idx)) {
+ sqfs_perror(node->name, "completing xattr key-value pairs",
+ ret);
+ return -1;
+ }
+
+ if (S_ISDIR(node->mode)) {
+ node = node->data.dir.children;
+
+ while (node != NULL) {
+ if (xattr_xcan_dfs(path_prefix, selinux_handle, xwr,
+ flags, node)) {
+ return -1;
+ }
+
+ node = node->next;
+ }
+ }
+
+ return 0;
+}
+
+int xattrs_from_dir(fstree_t *fs, const char *path, void *selinux_handle,
+ sqfs_xattr_writer_t *xwr, unsigned int flags)
+{
+ if (xwr == NULL)
+ return 0;
+
+ if (selinux_handle == NULL && !(flags & DIR_SCAN_READ_XATTR))
+ return 0;
+
+ return xattr_xcan_dfs(path, selinux_handle, xwr, flags, fs->root);
+}