image: Tar backend: Fix ups

* Use <filesystem> portably.

* Create the target directory if it doesn't exist.

* Fix symlink detection bug that could cause target mtab to halt
  image creation.

1 files changed, 26 insertions, 10 deletions

diff --git a/image/backends/tar.cc b/image/backends/tar.cc
index efd38e5..d9c2248 100644
--- a/image/backends/tar.cc
+++ b/image/backends/tar.cc
@@ -48,6 +48,7 @@ public:
 
     int prepare() override {
         int res;
+        error_code ec;
 
         a = archive_write_new();
         archive_write_set_format_pax_restricted(a);
@@ -66,6 +67,20 @@ public:
             break;
         }
 
+        output_info("tar backend", "creating directory tree");
+        fs::create_directory(this->ir_dir, ec);
+        if(ec && ec.value() != EEXIST) {
+            output_error("tar backend", "could not create IR directory",
+                         ec.message());
+            return 1;
+        }
+        fs::create_directory(this->ir_dir + "/target", ec);
+        if(ec && ec.value() != EEXIST) {
+            output_error("tar backend", "could not create target directory",
+                         ec.message());
+            return 1;
+        }
+
         res = archive_write_open_filename(a, this->out_path.c_str());
         if(res < ARCHIVE_OK) {
             if(res < ARCHIVE_WARN) {
@@ -93,17 +108,18 @@ public:
 
         for(const auto& dent : fs::recursive_directory_iterator(target, ec)) {
             fs::path relpath = dent.path().lexically_relative(target);
+            std::string pathstr(dent.path().native());
 #define OUTPUT_FAILURE(x) \
-    output_error("tar backend", "failed to " x " '" + std::string(dent.path()) + "'",\
+    output_error("tar backend", "failed to " x " '" + pathstr + "'",\
                  strerror(errno));
-            r = lstat(dent.path().c_str(), &s);
+            r = lstat(pathstr.c_str(), &s);
             if(r == -1) {
                 OUTPUT_FAILURE("stat")
                 code = -1;
                 goto ret;
             }
             archive_entry_copy_stat(entry, &s);
-            if(dent.is_symlink()) {
+            if(fs::is_symlink(dent)) {
                 archive_entry_set_filetype(entry, AE_IFLNK);
                 fs::path resolved = fs::read_symlink(dent.path(), ec);
                 if(ec) {
@@ -112,31 +128,31 @@ public:
                     code = -1;
                     goto ret;
                 }
-                const auto r_path = resolved.u8string();
+                const auto r_path = resolved.native();
                 archive_entry_update_symlink_utf8(entry, r_path.c_str());
             }
-            archive_entry_update_pathname_utf8(entry, relpath.u8string().c_str());
+            archive_entry_update_pathname_utf8(entry, relpath.native().c_str());
             if(archive_write_header(this->a, entry) != ARCHIVE_OK) {
                 output_error("tar backend", archive_error_string(a));
                 code = -1;
                 goto ret;
             }
-            if(dent.is_regular_file() && dent.file_size() > 0) {
-                fd = open(dent.path().c_str(), O_RDONLY);
+            if(fs::is_regular_file(dent) && !fs::is_symlink(dent) &&
+               s.st_size > 0) {
+                fd = open(pathstr.c_str(), O_RDONLY);
                 if(fd == -1) {
                     OUTPUT_FAILURE("open")
                     code = -1;
                     goto ret;
                 }
-                buff = mmap(NULL, dent.file_size(), PROT_READ, MAP_SHARED,
-                            fd, 0);
+                buff = mmap(NULL, s.st_size, PROT_READ, MAP_SHARED, fd, 0);
                 if(buff == MAP_FAILED) {
                     OUTPUT_FAILURE("map")
                     close(fd);
                     code = -1;
                     goto ret;
                 }
-                archive_write_data(this->a, buff, dent.file_size());
+                archive_write_data(this->a, buff, s.st_size);
                 close(fd);
             }
             archive_write_finish_entry(this->a);