From aed35f04f974370bcb7398d5379c6e082efaf6ef Mon Sep 17 00:00:00 2001
From: Marcus Holland-Moritz <github@mhxnet.de>
Date: Sun, 13 Dec 2020 22:43:02 +0100
Subject: [PATCH] Improved error handling

---
 CMakeLists.txt                  |  10 +-
 include/dwarfs/error.h          |  56 ++++++---
 include/dwarfs/logger.h         |   3 +-
 src/dwarfs.cpp                  |  34 +++---
 src/dwarfs/block_compressor.cpp |  67 +++++------
 src/dwarfs/block_manager.cpp    |  10 +-
 src/dwarfs/entry.cpp            |   6 +-
 src/dwarfs/error.cpp            |  80 +++++++++++++
 src/dwarfs/filesystem_v2.cpp    |  30 ++---
 src/dwarfs/inode_manager.cpp    |  14 +--
 src/dwarfs/logger.cpp           |   2 +-
 src/dwarfs/metadata_v2.cpp      |  35 +++---
 src/dwarfs/mmap.cpp             |  14 +--
 src/dwarfs/options.cpp          |   3 +-
 src/dwarfs/os_access_posix.cpp  |  16 +--
 src/dwarfs/python_script.cpp    |  32 ++---
 src/dwarfs/scanner.cpp          |   5 +-
 src/dwarfs/util.cpp             |   4 +-
 src/dwarfs/worker_group.cpp     |   4 +-
 src/dwarfsck.cpp                |  44 ++++---
 src/mkdwarfs.cpp                | 202 ++++++++++++++++++++------------
 21 files changed, 418 insertions(+), 253 deletions(-)
 create mode 100644 src/dwarfs/error.cpp

diff --git a/CMakeLists.txt b/CMakeLists.txt
index df0d5e30..ea8fc60b 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -152,6 +152,7 @@ list(
   src/dwarfs/block_manager.cpp
   src/dwarfs/console_writer.cpp
   src/dwarfs/entry.cpp
+  src/dwarfs/error.cpp
   src/dwarfs/filesystem_v2.cpp
   src/dwarfs/filesystem_writer.cpp
   src/dwarfs/fstypes.cpp
@@ -351,7 +352,7 @@ target_link_libraries(
   PkgConfig::LIBLZ4
   PkgConfig::LIBLZMA)
 
-foreach(tgt dwarfs-bin mkdwarfs dwarfsck dwarfsbench)
+foreach(tgt ${BINARY_TARGETS})
   target_link_libraries(${tgt} dwarfs)
   target_link_libraries(${tgt} -Wl,--whole-archive folly_exception_tracer_base
                         folly_exception_tracer -Wl,--no-whole-archive)
@@ -363,13 +364,8 @@ if(WITH_PYTHON)
   endif()
 
   target_link_libraries(mkdwarfs ${BOOST_PYTHON_LIBS} ${Python3_LIBRARIES})
-endif()
 
-if(WITH_TESTS)
-  foreach(tgt dwarfs_test dwarfs_compat_test)
-    target_link_libraries(${tgt} dwarfs)
-  endforeach()
-  if(WITH_PYTHON)
+  if(WITH_TESTS)
     foreach(tgt dwarfs_test dwarfs_compat_test)
       target_link_libraries(${tgt} ${BOOST_PYTHON_LIBS} ${Python3_LIBRARIES})
     endforeach()
diff --git a/include/dwarfs/error.h b/include/dwarfs/error.h
index 1d03a819..4e7ca7fd 100644
--- a/include/dwarfs/error.h
+++ b/include/dwarfs/error.h
@@ -22,34 +22,56 @@
 #pragma once
 
 #include <exception>
+#include <functional>
+#include <string>
+
+#include <boost/system/error_code.hpp>
+#include <boost/system/system_error.hpp>
 
 namespace dwarfs {
 
 class error : public std::exception {
  public:
-  error(const std::string& str, int err_no) noexcept
-      : what_(str)
-      , errno_(err_no) {}
+  error(std::string const& s, char const* file, int line) noexcept
+      : what_(s)
+      , file_(file)
+      , line_(line) {}
 
-  error(const error& e) noexcept
-      : what_(e.what_)
-      , errno_(e.errno_) {}
+  char const* what() const noexcept override { return what_.c_str(); }
 
-  error& operator=(const error& e) noexcept {
-    if (&e != this) {
-      what_ = e.what_;
-      errno_ = e.errno_;
-    }
-    return *this;
-  }
+  char const* file() const { return file_; }
 
-  const char* what() const noexcept override { return what_.c_str(); }
-
-  int get_errno() const { return errno_; }
+  int line() const { return line_; }
 
  private:
   std::string what_;
-  int errno_;
+  char const* file_;
+  int line_;
 };
 
+class system_error : public boost::system::system_error {
+ public:
+  system_error(char const* file, int line) noexcept;
+  system_error(std::string const& s, char const* file, int line) noexcept;
+  system_error(std::string const& s, int err, char const* file,
+               int line) noexcept;
+  system_error(int err, char const* file, int line) noexcept;
+
+  int get_errno() const { return code().value(); }
+
+  char const* file() const { return file_; }
+
+  int line() const { return line_; }
+
+ private:
+  char const* file_;
+  int line_;
+};
+
+#define DWARFS_THROW(cls, ...) throw cls(__VA_ARGS__, __FILE__, __LINE__)
+
+void dump_exceptions();
+
+int safe_main(std::function<int(void)> fn);
+
 } // namespace dwarfs
diff --git a/include/dwarfs/logger.h b/include/dwarfs/logger.h
index 6d06875a..0abbd258 100644
--- a/include/dwarfs/logger.h
+++ b/include/dwarfs/logger.h
@@ -36,6 +36,7 @@
 #include <type_traits>
 #include <utility>
 
+#include "dwarfs/error.h"
 #include "dwarfs/util.h"
 
 namespace dwarfs {
@@ -302,7 +303,7 @@ template <template <class> class T, class CreatePolicy, class LoggerPolicyList>
 struct logging_class_factory<T, CreatePolicy, LoggerPolicyList, 0> {
   template <class... Args>
   static typename CreatePolicy::return_type create(logger& lgr, Args&&...) {
-    throw std::runtime_error("no such logger policy: " + lgr.policy_name());
+    DWARFS_THROW(error, "no such logger policy: " + lgr.policy_name());
   }
 };
 
diff --git a/src/dwarfs.cpp b/src/dwarfs.cpp
index 4c64840a..066b93c1 100644
--- a/src/dwarfs.cpp
+++ b/src/dwarfs.cpp
@@ -113,7 +113,7 @@ void op_init(void* /*userdata*/, struct fuse_conn_info* /*conn*/) {
         &s_opts.stat_defaults, FUSE_ROOT_ID);
 
     ti << "file system initialized";
-  } catch (const std::exception& e) {
+  } catch (std::exception const& e) {
     log.error() << "error initializing file system: " << e.what();
     fuse_session_exit(s_session);
   }
@@ -148,10 +148,10 @@ void op_lookup(fuse_req_t req, fuse_ino_t parent, const char* name) {
         return;
       }
     }
-  } catch (const dwarfs::error& e) {
+  } catch (dwarfs::system_error const& e) {
     std::cerr << "ERROR: " << e.what() << std::endl;
     err = e.get_errno();
-  } catch (const std::exception& e) {
+  } catch (std::exception const& e) {
     std::cerr << "ERROR: " << e.what() << std::endl;
     err = EIO;
   }
@@ -179,10 +179,10 @@ void op_getattr(fuse_req_t req, fuse_ino_t ino, struct fuse_file_info*) {
         return;
       }
     }
-  } catch (const dwarfs::error& e) {
+  } catch (dwarfs::system_error const& e) {
     std::cerr << "ERROR: " << e.what() << std::endl;
     err = e.get_errno();
-  } catch (const std::exception& e) {
+  } catch (std::exception const& e) {
     std::cerr << "ERROR: " << e.what() << std::endl;
     err = EIO;
   }
@@ -203,10 +203,10 @@ void op_access(fuse_req_t req, fuse_ino_t ino, int mode) {
       auto ctx = fuse_req_ctx(req);
       err = s_fs->access(*entry, mode, ctx->uid, ctx->gid);
     }
-  } catch (const dwarfs::error& e) {
+  } catch (dwarfs::system_error const& e) {
     std::cerr << "ERROR: " << e.what() << std::endl;
     err = e.get_errno();
-  } catch (const std::exception& e) {
+  } catch (std::exception const& e) {
     std::cerr << "ERROR: " << e.what() << std::endl;
     err = EIO;
   }
@@ -233,10 +233,10 @@ void op_readlink(fuse_req_t req, fuse_ino_t ino) {
         return;
       }
     }
-  } catch (const dwarfs::error& e) {
+  } catch (dwarfs::system_error const& e) {
     std::cerr << "ERROR: " << e.what() << std::endl;
     err = e.get_errno();
-  } catch (const std::exception& e) {
+  } catch (std::exception const& e) {
     std::cerr << "ERROR: " << e.what() << std::endl;
     err = EIO;
   }
@@ -265,10 +265,10 @@ void op_open(fuse_req_t req, fuse_ino_t ino, struct fuse_file_info* fi) {
         return;
       }
     }
-  } catch (const dwarfs::error& e) {
+  } catch (dwarfs::system_error const& e) {
     std::cerr << "ERROR: " << e.what() << std::endl;
     err = e.get_errno();
-  } catch (const std::exception& e) {
+  } catch (std::exception const& e) {
     std::cerr << "ERROR: " << e.what() << std::endl;
     err = EIO;
   }
@@ -300,10 +300,10 @@ void op_read(fuse_req_t req, fuse_ino_t ino, size_t size, off_t off,
     } else {
       err = EIO;
     }
-  } catch (const dwarfs::error& e) {
+  } catch (dwarfs::system_error const& e) {
     std::cerr << "ERROR: " << e.what() << std::endl;
     err = e.get_errno();
-  } catch (const std::exception& e) {
+  } catch (std::exception const& e) {
     std::cerr << "ERROR: " << e.what() << std::endl;
     err = EIO;
   }
@@ -357,10 +357,10 @@ void op_readdir(fuse_req_t req, fuse_ino_t ino, size_t size, off_t off,
 
       err = ENOTDIR;
     }
-  } catch (const dwarfs::error& e) {
+  } catch (dwarfs::system_error const& e) {
     std::cerr << "ERROR: " << e.what() << std::endl;
     err = e.get_errno();
-  } catch (const std::exception& e) {
+  } catch (std::exception const& e) {
     std::cerr << "ERROR: " << e.what() << std::endl;
     err = EIO;
   }
@@ -383,10 +383,10 @@ void op_statfs(fuse_req_t req, fuse_ino_t /*ino*/) {
 
       return;
     }
-  } catch (const dwarfs::error& e) {
+  } catch (dwarfs::system_error const& e) {
     std::cerr << "ERROR: " << e.what() << std::endl;
     err = e.get_errno();
-  } catch (const std::exception& e) {
+  } catch (std::exception const& e) {
     std::cerr << "ERROR: " << e.what() << std::endl;
     err = EIO;
   }
diff --git a/src/dwarfs/block_compressor.cpp b/src/dwarfs/block_compressor.cpp
index 5a717d24..540d17f9 100644
--- a/src/dwarfs/block_compressor.cpp
+++ b/src/dwarfs/block_compressor.cpp
@@ -26,7 +26,6 @@
 #include <cstring>
 #include <iterator>
 #include <memory>
-#include <stdexcept>
 #include <unordered_map>
 
 #include <sys/types.h>
@@ -53,6 +52,7 @@
 #endif
 
 #include "dwarfs/block_compressor.h"
+#include "dwarfs/error.h"
 #include "dwarfs/fstypes.h"
 
 namespace dwarfs {
@@ -72,8 +72,8 @@ class option_map {
       boost::split(kv, arg[i], boost::is_any_of("="));
 
       if (kv.size() > 2) {
-        throw std::runtime_error("error parsing option " + kv[0] +
-                                 " for choice " + choice_);
+        DWARFS_THROW(error, "error parsing option " + kv[0] + " for choice " +
+                                choice_);
       }
 
       opt_[kv[0]] = kv.size() > 1 ? kv[1] : std::string("1");
@@ -101,8 +101,8 @@ class option_map {
       std::transform(
           opt_.begin(), opt_.end(), std::back_inserter(invalid),
           [](const std::pair<std::string, std::string>& p) { return p.first; });
-      throw std::runtime_error("invalid option(s) for choice " + choice_ +
-                               ": " + boost::join(invalid, ", "));
+      DWARFS_THROW(error, "invalid option(s) for choice " + choice_ + ": " +
+                              boost::join(invalid, ", "));
     }
   }
 
@@ -164,7 +164,7 @@ class lzma_block_compressor : public block_compressor::impl {
     auto i = vm.find(binary);
 
     if (i == vm.end()) {
-      throw std::runtime_error("unsupported binary mode");
+      DWARFS_THROW(error, "unsupported binary mode");
     }
 
     return i->second;
@@ -215,7 +215,7 @@ lzma_block_compressor::lzma_block_compressor(unsigned level, bool extreme,
     : stream_(LZMA_STREAM_INIT)
     , data_(block_size > 0 ? lzma_stream_buffer_bound(block_size) : 0) {
   if (lzma_lzma_preset(&opt_lzma_, get_preset(level, extreme))) {
-    throw std::runtime_error("unsupported preset, possibly a bug");
+    DWARFS_THROW(error, "unsupported preset, possibly a bug");
   }
 
   if (dict_size > 0) {
@@ -233,7 +233,7 @@ lzma_block_compressor::lzma_block_compressor(unsigned level, bool extreme,
     auto* filters = &filters_[filters_[0].id == LZMA_VLI_UNKNOWN];
 
     if (lzma_stream_encoder(&stream_, filters, LZMA_CHECK_CRC64)) {
-      throw std::runtime_error("lzma_stream_encoder");
+      DWARFS_THROW(error, "lzma_stream_encoder");
     }
 
     stream_.next_out = data_.data();
@@ -253,18 +253,18 @@ void lzma_block_compressor::append(const uint8_t* data, size_t size,
   switch (ret) {
   case LZMA_STREAM_END:
     if (!last) {
-      throw std::runtime_error("LZMA unexpected stream end");
+      DWARFS_THROW(error, "LZMA unexpected stream end");
     }
     break;
 
   case LZMA_MEM_ERROR:
-    throw std::runtime_error("LZMA_MEM_ERROR");
+    DWARFS_THROW(error, "LZMA_MEM_ERROR");
 
   case LZMA_DATA_ERROR:
-    throw std::runtime_error("LZMA_DATA_ERROR");
+    DWARFS_THROW(error, "LZMA_DATA_ERROR");
 
   default:
-    throw std::runtime_error("unknown LZMA error");
+    DWARFS_THROW(error, "unknown LZMA error");
   }
 
   if (last) {
@@ -280,7 +280,7 @@ lzma_block_compressor::compress(const std::vector<uint8_t>& data,
   lzma_stream s = LZMA_STREAM_INIT;
 
   if (lzma_stream_encoder(&s, filters, LZMA_CHECK_CRC64)) {
-    throw std::runtime_error("lzma_stream_encoder");
+    DWARFS_THROW(error, "lzma_stream_encoder");
   }
 
   lzma_action action = LZMA_FINISH;
@@ -304,13 +304,13 @@ lzma_block_compressor::compress(const std::vector<uint8_t>& data,
     break;
 
   case LZMA_MEM_ERROR:
-    throw std::runtime_error("LZMA_MEM_ERROR");
+    DWARFS_THROW(error, "LZMA_MEM_ERROR");
 
   case LZMA_DATA_ERROR:
-    throw std::runtime_error("LZMA_DATA_ERROR");
+    DWARFS_THROW(error, "LZMA_DATA_ERROR");
 
   default:
-    throw std::runtime_error("unknown LZMA error");
+    DWARFS_THROW(error, "unknown LZMA error");
   }
 
   return compressed;
@@ -372,7 +372,7 @@ class lz4_block_compressor : public block_compressor::impl {
         Policy::compress(&data[0], &compressed[sizeof(uint32_t)], data.size(),
                          compressed.size() - sizeof(uint32_t), level_);
     if (csize == 0) {
-      throw std::runtime_error("error during compression");
+      DWARFS_THROW(error, "error during compression");
     }
     compressed.resize(sizeof(uint32_t) + csize);
     return compressed;
@@ -474,7 +474,7 @@ block_compressor::block_compressor(const std::string& spec, size_t block_size) {
         om.get<int>("level", ZSTD_maxCLevel()));
 #endif
   } else {
-    throw std::runtime_error("unknown compression: " + om.choice());
+    DWARFS_THROW(error, "unknown compression: " + om.choice());
   }
 
   om.report();
@@ -528,7 +528,7 @@ class lzma_block_decompressor : public block_decompressor::impl {
     stream_.avail_in = size;
     if (lzma_stream_decoder(&stream_, UINT64_MAX, LZMA_CONCATENATED) !=
         LZMA_OK) {
-      throw std::runtime_error("lzma_stream_decoder");
+      DWARFS_THROW(error, "lzma_stream_decoder");
     }
     decompressed_.reserve(uncompressed_size_);
   }
@@ -561,9 +561,10 @@ class lzma_block_decompressor : public block_decompressor::impl {
 
     if (ret != (action == LZMA_RUN ? LZMA_OK : LZMA_STREAM_END) ||
         stream_.avail_out != 0) {
-      throw std::runtime_error(folly::to<std::string>(
-          "error while decompressing LZMA stream (action=", action,
-          ", ret=", ret, ", stream_.avail_out=", stream_.avail_out, ")"));
+      DWARFS_THROW(error,
+                   fmt::format("error while decompressing LZMA stream "
+                               "(action={0}, ret={1}, stream_.avail_out={2})",
+                               action, ret, stream_.avail_out));
     }
 
     return ret == LZMA_STREAM_END;
@@ -638,7 +639,7 @@ class zstd_block_decompressor : public block_decompressor::impl {
     auto rv = ZSTD_decompress(decompressed_.data(), decompressed_.size(), data_,
                               size_);
     if (ZSTD_isError(rv)) {
-      throw std::runtime_error(fmt::format("ZSTD: {}", ZSTD_getErrorName(rv)));
+      DWARFS_THROW(error, fmt::format("ZSTD: {}", ZSTD_getErrorName(rv)));
     }
     return true;
   }
@@ -657,7 +658,7 @@ class zstd_block_decompressor : public block_decompressor::impl {
 size_t lzma_block_decompressor::get_uncompressed_size(const uint8_t* data,
                                                       size_t size) {
   if (size < 2 * LZMA_STREAM_HEADER_SIZE) {
-    throw std::runtime_error("lzma compressed block is too small");
+    DWARFS_THROW(error, "lzma compressed block is too small");
   }
 
   lzma_stream s = LZMA_STREAM_INIT;
@@ -671,26 +672,26 @@ size_t lzma_block_decompressor::get_uncompressed_size(const uint8_t* data,
     --ptr;
 
     if (pos < 2 * LZMA_STREAM_HEADER_SIZE) {
-      throw std::runtime_error("data error (stream padding)");
+      DWARFS_THROW(error, "data error (stream padding)");
     }
   }
 
   lzma_stream_flags footer_flags;
 
   if (lzma_stream_footer_decode(&footer_flags, data + pos) != LZMA_OK) {
-    throw std::runtime_error("lzma_stream_footer_decode()");
+    DWARFS_THROW(error, "lzma_stream_footer_decode()");
   }
 
   lzma_vli index_size = footer_flags.backward_size;
   if (static_cast<lzma_vli>(pos) < index_size + LZMA_STREAM_HEADER_SIZE) {
-    throw std::runtime_error("data error (index size)");
+    DWARFS_THROW(error, "data error (index size)");
   }
 
   pos -= index_size;
   lzma_index* index = NULL;
 
   if (lzma_index_decoder(&s, &index, UINT64_MAX) != LZMA_OK) {
-    throw std::runtime_error("lzma_index_decoder()");
+    DWARFS_THROW(error, "lzma_index_decoder()");
   }
 
   s.avail_in = index_size;
@@ -698,13 +699,13 @@ size_t lzma_block_decompressor::get_uncompressed_size(const uint8_t* data,
 
   lzma_ret ret = lzma_code(&s, LZMA_RUN);
   if (ret != LZMA_STREAM_END || s.avail_in != 0) {
-    throw std::runtime_error(
-        fmt::format("lzma_code(): {} (avail_in={})", ret, s.avail_in));
+    DWARFS_THROW(error,
+                 fmt::format("lzma_code(): {} (avail_in={})", ret, s.avail_in));
   }
 
   pos -= LZMA_STREAM_HEADER_SIZE;
   if (static_cast<lzma_vli>(pos) < lzma_index_total_size(index)) {
-    throw std::runtime_error("data error (index total size)");
+    DWARFS_THROW(error, "data error (index total size)");
   }
 
   size_t usize = lzma_index_uncompressed_size(index);
@@ -745,8 +746,8 @@ block_decompressor::block_decompressor(compression_type type,
 #endif
 
   default:
-    throw std::runtime_error("unsupported compression type: " +
-                             get_compression_name(type));
+    DWARFS_THROW(error,
+                 "unsupported compression type: " + get_compression_name(type));
   }
 }
 } // namespace dwarfs
diff --git a/src/dwarfs/block_manager.cpp b/src/dwarfs/block_manager.cpp
index 1a8d5b87..e0d03666 100644
--- a/src/dwarfs/block_manager.cpp
+++ b/src/dwarfs/block_manager.cpp
@@ -23,7 +23,6 @@
 #include <cstdint>
 #include <cstring>
 #include <map>
-#include <stdexcept>
 #include <string>
 #include <type_traits>
 #include <utility>
@@ -34,6 +33,7 @@
 
 #include "dwarfs/block_manager.h"
 #include "dwarfs/entry.h"
+#include "dwarfs/error.h"
 #include "dwarfs/filesystem_writer.h"
 #include "dwarfs/inode.h"
 #include "dwarfs/inode_hasher.h"
@@ -229,8 +229,7 @@ void block_manager_<LoggerPolicy>::update_hashes(const hash_map_type& hm,
       auto& stats = stats_[bhi->size];
 
       if (hmi == hm.end()) {
-        throw std::runtime_error(
-            "internal error: no hash found for window size");
+        DWARFS_THROW(error, "internal error: no hash found for window size");
       }
 
       const auto& hashvec = hmi->second;
@@ -241,7 +240,7 @@ void block_manager_<LoggerPolicy>::update_hashes(const hash_map_type& hm,
         log_.error() << "bhi=" << bhi->size
                      << ", hashvec.size()=" << hashvec.size()
                      << ", offset=" << offset << ", last=" << last;
-        throw std::runtime_error("internal error: hashvec too small");
+        DWARFS_THROW(error, "internal error: hashvec too small");
       }
 
       for (size_t off = 0; off < last; off += incr) {
@@ -410,8 +409,7 @@ void block_manager_<LoggerPolicy>::segment_and_add_data(
       auto& stats = stats_[bhcur->size];
 
       if (hmi == hm.end()) {
-        throw std::runtime_error(
-            "internal error: no hash found for window size");
+        DWARFS_THROW(error, "internal error: no hash found for window size");
       }
 
       const auto& hashvec = hmi->second;
diff --git a/src/dwarfs/entry.cpp b/src/dwarfs/entry.cpp
index 844a70f7..25c28d84 100644
--- a/src/dwarfs/entry.cpp
+++ b/src/dwarfs/entry.cpp
@@ -21,7 +21,6 @@
 
 #include <algorithm>
 #include <cstring>
-#include <stdexcept>
 #include <utility>
 
 #include <openssl/sha.h>
@@ -29,6 +28,7 @@
 #include <fmt/format.h>
 
 #include "dwarfs/entry.h"
+#include "dwarfs/error.h"
 #include "dwarfs/global_entry_data.h"
 #include "dwarfs/inode.h"
 #include "dwarfs/mmif.h"
@@ -86,7 +86,7 @@ std::string entry::type_string() const {
     return "socket";
   }
 
-  throw std::runtime_error(fmt::format("unknown file type: {:#06x}", mode));
+  DWARFS_THROW(error, fmt::format("unknown file type: {:#06x}", mode));
 }
 
 void entry::walk(std::function<void(entry*)> const& f) { f(this); }
@@ -150,7 +150,7 @@ std::string_view file::hash() const {
 
 void file::set_inode(std::shared_ptr<inode> ino) {
   if (inode_) {
-    throw std::runtime_error("inode already set for file");
+    DWARFS_THROW(error, "inode already set for file");
   }
 
   inode_ = std::move(ino);
diff --git a/src/dwarfs/error.cpp b/src/dwarfs/error.cpp
new file mode 100644
index 00000000..cb36613a
--- /dev/null
+++ b/src/dwarfs/error.cpp
@@ -0,0 +1,80 @@
+/* vim:set ts=2 sw=2 sts=2 et: */
+/**
+ * \author     Marcus Holland-Moritz (github@mhxnet.de)
+ * \copyright  Copyright (c) Marcus Holland-Moritz
+ *
+ * This file is part of dwarfs.
+ *
+ * dwarfs is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * dwarfs is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with dwarfs.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+#include <cerrno>
+#include <iostream>
+
+#include <folly/String.h>
+#include <folly/experimental/exception_tracer/ExceptionTracer.h>
+#include <folly/experimental/symbolizer/SignalHandler.h>
+
+#include "dwarfs/error.h"
+
+namespace dwarfs {
+
+system_error::system_error(char const* file, int line) noexcept
+    : system_error(errno, file, line) {}
+
+system_error::system_error(std::string const& s, char const* file,
+                           int line) noexcept
+    : system_error(s, errno, file, line) {}
+
+system_error::system_error(std::string const& s, int err, char const* file,
+                           int line) noexcept
+    : boost::system::system_error(err, boost::system::generic_category(),
+                                  s.c_str())
+    , file_(file)
+    , line_(line) {}
+
+system_error::system_error(int err, char const* file, int line) noexcept
+    : boost::system::system_error(err, boost::system::generic_category())
+    , file_(file)
+    , line_(line) {}
+
+void dump_exceptions() {
+  auto exceptions = ::folly::exception_tracer::getCurrentExceptions();
+  for (auto& exc : exceptions) {
+    std::cerr << exc << std::endl;
+  }
+}
+
+int safe_main(std::function<int(void)> fn) {
+  try {
+    folly::symbolizer::installFatalSignalHandler();
+    return fn();
+  } catch (system_error const& e) {
+    std::cerr << "ERROR: " << folly::exceptionStr(e) << " [" << e.file() << ":"
+              << e.line() << "]" << std::endl;
+    dump_exceptions();
+  } catch (error const& e) {
+    std::cerr << "ERROR: " << folly::exceptionStr(e) << " [" << e.file() << ":"
+              << e.line() << "]" << std::endl;
+    dump_exceptions();
+  } catch (std::exception const& e) {
+    std::cerr << "ERROR: " << folly::exceptionStr(e) << std::endl;
+    dump_exceptions();
+  } catch (...) {
+    dump_exceptions();
+  }
+  return 1;
+}
+
+} // namespace dwarfs
diff --git a/src/dwarfs/filesystem_v2.cpp b/src/dwarfs/filesystem_v2.cpp
index 18bd1f3e..d9e98878 100644
--- a/src/dwarfs/filesystem_v2.cpp
+++ b/src/dwarfs/filesystem_v2.cpp
@@ -22,7 +22,6 @@
 #include <cstddef>
 #include <cstring>
 #include <optional>
-#include <stdexcept>
 #include <unordered_map>
 #include <vector>
 
@@ -37,6 +36,7 @@
 
 #include "dwarfs/block_cache.h"
 #include "dwarfs/block_compressor.h"
+#include "dwarfs/error.h"
 #include "dwarfs/filesystem_v2.h"
 #include "dwarfs/filesystem_writer.h"
 #include "dwarfs/fstypes.h"
@@ -62,21 +62,21 @@ class filesystem_parser {
       : mm_(mm)
       , offset_(sizeof(file_header)) {
     if (mm_->size() < sizeof(file_header)) {
-      throw std::runtime_error("file too small");
+      DWARFS_THROW(error, "file too small");
     }
 
     const file_header* fh = mm_->as<file_header>();
 
     if (::memcmp(&fh->magic[0], "DWARFS", 6) != 0) {
-      throw std::runtime_error("magic not found");
+      DWARFS_THROW(error, "magic not found");
     }
 
     if (fh->major != MAJOR_VERSION) {
-      throw std::runtime_error("different major version");
+      DWARFS_THROW(error, "different major version");
     }
 
     if (fh->minor > MINOR_VERSION) {
-      throw std::runtime_error("newer minor version");
+      DWARFS_THROW(error, "newer minor version");
     }
   }
 
@@ -91,7 +91,7 @@ class filesystem_parser {
       offset_ += sizeof(section_header);
 
       if (offset_ + sh.length > mm_->size()) {
-        throw std::runtime_error("truncated file");
+        DWARFS_THROW(error, "truncated file");
       }
 
       start = offset_;
@@ -151,11 +151,11 @@ make_metadata(logger& lgr, std::shared_ptr<mmif> mm,
   auto meta_it = sections.find(section_type::METADATA_V2);
 
   if (schema_it == sections.end()) {
-    throw std::runtime_error("no metadata schema found");
+    DWARFS_THROW(error, "no metadata schema found");
   }
 
   if (meta_it == sections.end()) {
-    throw std::runtime_error("no metadata found");
+    DWARFS_THROW(error, "no metadata found");
   }
 
   auto& meta_section = meta_it->second;
@@ -166,7 +166,7 @@ make_metadata(logger& lgr, std::shared_ptr<mmif> mm,
   if (lock_mode != mlock_mode::NONE) {
     if (auto ec = mm->lock(meta_section.start, meta_section_range.size())) {
       if (lock_mode == mlock_mode::MUST) {
-        throw boost::system::system_error(ec, "mlock");
+        DWARFS_THROW(system_error, "mlock");
       } else {
         log.warn() << "mlock() failed: " << ec.message();
       }
@@ -241,8 +241,8 @@ filesystem_<LoggerPolicy>::filesystem_(logger& lgr, std::shared_ptr<mmif> mm,
                    static_cast<size_t>(s->header.length));
     } else {
       if (!sections.emplace(s->header.type, *s).second) {
-        throw std::runtime_error("duplicate section: " +
-                                 get_section_name(s->header.type));
+        DWARFS_THROW(error,
+                     "duplicate section: " + get_section_name(s->header.type));
       }
     }
   }
@@ -398,8 +398,8 @@ void filesystem_v2::rewrite(logger& lgr, progress& prog,
       ++prog.block_count;
     } else {
       if (!sections.emplace(s->header.type, *s).second) {
-        throw std::runtime_error("duplicate section: " +
-                                 get_section_name(s->header.type));
+        DWARFS_THROW(error,
+                     "duplicate section: " + get_section_name(s->header.type));
       }
     }
   }
@@ -452,8 +452,8 @@ void filesystem_v2::identify(logger& lgr, std::shared_ptr<mmif> mm,
 
     if (s->header.type != section_type::BLOCK) {
       if (!sections.emplace(s->header.type, *s).second) {
-        throw std::runtime_error("duplicate section: " +
-                                 get_section_name(s->header.type));
+        DWARFS_THROW(error,
+                     "duplicate section: " + get_section_name(s->header.type));
       }
     }
   }
diff --git a/src/dwarfs/inode_manager.cpp b/src/dwarfs/inode_manager.cpp
index f15a6e99..a1f1e125 100644
--- a/src/dwarfs/inode_manager.cpp
+++ b/src/dwarfs/inode_manager.cpp
@@ -25,11 +25,11 @@
 #include <deque>
 #include <limits>
 #include <numeric>
-#include <stdexcept>
 #include <string>
 #include <vector>
 
 #include "dwarfs/entry.h"
+#include "dwarfs/error.h"
 #include "dwarfs/inode.h"
 #include "dwarfs/inode_manager.h"
 #include "dwarfs/logger.h"
@@ -56,21 +56,21 @@ class inode_ : public inode {
 
   uint32_t similarity_hash() const override {
     if (files_.empty()) {
-      throw std::runtime_error("inode has no file");
+      DWARFS_THROW(error, "inode has no file");
     }
     return similarity_hash_;
   }
 
   std::vector<uint64_t> const& nilsimsa_similarity_hash() const override {
     if (files_.empty()) {
-      throw std::runtime_error("inode has no file");
+      DWARFS_THROW(error, "inode has no file");
     }
     return nilsimsa_similarity_hash_;
   }
 
   void set_files(files_vector&& fv) override {
     if (!files_.empty()) {
-      throw std::runtime_error("files already set for inode");
+      DWARFS_THROW(error, "files already set for inode");
     }
 
     files_ = std::move(fv);
@@ -110,7 +110,7 @@ class inode_ : public inode {
 
   file const* any() const override {
     if (files_.empty()) {
-      throw std::runtime_error("inode has no file");
+      DWARFS_THROW(error, "inode has no file");
     }
     return files_.front();
   }
@@ -247,7 +247,7 @@ void inode_manager_<LoggerPolicy>::order_inodes(
 
   case file_order_mode::SCRIPT: {
     if (!scr->has_order()) {
-      throw std::runtime_error("script cannot order inodes");
+      DWARFS_THROW(error, "script cannot order inodes");
     }
     log_.info() << "ordering " << count() << " inodes using script...";
     auto ti = log_.timed_info();
@@ -390,7 +390,7 @@ void inode_manager_<LoggerPolicy>::order_inodes_by_nilsimsa(
   }
 
   if (count != inodes_.size()) {
-    throw std::runtime_error("internal error: nilsimsa ordering failed");
+    DWARFS_THROW(error, "internal error: nilsimsa ordering failed");
   }
 }
 
diff --git a/src/dwarfs/logger.cpp b/src/dwarfs/logger.cpp
index d4ffec9f..7ff10116 100644
--- a/src/dwarfs/logger.cpp
+++ b/src/dwarfs/logger.cpp
@@ -87,7 +87,7 @@ logger::level_type logger::parse_level(std::string_view level) {
   if (level == "trace") {
     return TRACE;
   }
-  throw std::runtime_error(fmt::format("invalid logger level: {}", level));
+  DWARFS_THROW(error, fmt::format("invalid logger level: {}", level));
 }
 
 stream_logger::stream_logger(std::ostream& os, level_type threshold)
diff --git a/src/dwarfs/metadata_v2.cpp b/src/dwarfs/metadata_v2.cpp
index 0c2273dd..92d62ece 100644
--- a/src/dwarfs/metadata_v2.cpp
+++ b/src/dwarfs/metadata_v2.cpp
@@ -37,6 +37,7 @@
 
 #include <fmt/format.h>
 
+#include "dwarfs/error.h"
 #include "dwarfs/logger.h"
 #include "dwarfs/metadata_v2.h"
 #include "dwarfs/options.h"
@@ -121,7 +122,8 @@ class metadata_ : public metadata_v2::impl {
     log_.debug() << "device index offset: " << dev_index_offset_;
 
     if (int(meta_.directories().size() - 1) != link_index_offset_) {
-      throw std::runtime_error(
+      DWARFS_THROW(
+          error,
           fmt::format("metadata inconsistency: number of directories ({}) does "
                       "not match link index ({})",
                       meta_.directories().size() - 1, link_index_offset_));
@@ -129,27 +131,32 @@ class metadata_ : public metadata_v2::impl {
 
     if (int(meta_.link_index().size()) !=
         (chunk_index_offset_ - link_index_offset_)) {
-      throw std::runtime_error(fmt::format(
-          "metadata inconsistency: number of links ({}) does not match "
-          "chunk/link index delta ({} - {} = {})",
-          meta_.link_index().size(), chunk_index_offset_, link_index_offset_,
-          chunk_index_offset_ - link_index_offset_));
+      DWARFS_THROW(
+          error,
+          fmt::format(
+              "metadata inconsistency: number of links ({}) does not match "
+              "chunk/link index delta ({} - {} = {})",
+              meta_.link_index().size(), chunk_index_offset_,
+              link_index_offset_, chunk_index_offset_ - link_index_offset_));
     }
 
     if (int(meta_.chunk_index().size() - 1) !=
         (dev_index_offset_ - chunk_index_offset_)) {
-      throw std::runtime_error(fmt::format(
-          "metadata inconsistency: number of files ({}) does not match "
-          "device/chunk index delta ({} - {} = {})",
-          meta_.chunk_index().size() - 1, dev_index_offset_,
-          chunk_index_offset_, dev_index_offset_ - chunk_index_offset_));
+      DWARFS_THROW(
+          error,
+          fmt::format(
+              "metadata inconsistency: number of files ({}) does not match "
+              "device/chunk index delta ({} - {} = {})",
+              meta_.chunk_index().size() - 1, dev_index_offset_,
+              chunk_index_offset_, dev_index_offset_ - chunk_index_offset_));
     }
 
     if (auto devs = meta_.devices()) {
       auto other_offset = find_index_offset(inode_rank::INO_OTH);
 
       if (devs->size() != (other_offset - dev_index_offset_)) {
-        throw std::runtime_error(
+        DWARFS_THROW(
+            error,
             fmt::format("metadata inconsistency: number of devices ({}) does "
                         "not match other/device index delta ({} - {} = {})",
                         devs->size(), other_offset, dev_index_offset_,
@@ -233,7 +240,7 @@ class metadata_ : public metadata_v2::impl {
     case S_IFIFO:
       return inode_rank::INO_OTH;
     default:
-      throw std::runtime_error(fmt::format("unknown file type: {:#06x}", mode));
+      DWARFS_THROW(error, fmt::format("unknown file type: {:#06x}", mode));
     }
   }
 
@@ -254,7 +261,7 @@ class metadata_ : public metadata_v2::impl {
     case S_IFIFO:
       return 'p';
     default:
-      throw std::runtime_error(fmt::format("unknown file type: {:#06x}", mode));
+      DWARFS_THROW(error, fmt::format("unknown file type: {:#06x}", mode));
     }
   }
 
diff --git a/src/dwarfs/mmap.cpp b/src/dwarfs/mmap.cpp
index 36f75e69..8b108fa6 100644
--- a/src/dwarfs/mmap.cpp
+++ b/src/dwarfs/mmap.cpp
@@ -20,7 +20,6 @@
  */
 
 #include <cerrno>
-#include <cstdio> // TODO
 
 #include <fcntl.h>
 #include <sys/mman.h>
@@ -28,8 +27,10 @@
 #include <unistd.h>
 
 #include <boost/system/error_code.hpp>
-#include <boost/system/system_error.hpp>
 
+#include <fmt/format.h>
+
+#include "dwarfs/error.h"
 #include "dwarfs/mmap.h"
 
 namespace dwarfs {
@@ -40,8 +41,7 @@ int safe_open(const std::string& path) {
   int fd = ::open(path.c_str(), O_RDONLY);
 
   if (fd == -1) {
-    throw boost::system::system_error(errno, boost::system::generic_category(),
-                                      "open");
+    DWARFS_THROW(system_error, fmt::format("open('{}')", path));
   }
 
   return fd;
@@ -50,8 +50,7 @@ int safe_open(const std::string& path) {
 size_t safe_size(int fd) {
   struct stat st;
   if (::fstat(fd, &st) == -1) {
-    throw boost::system::system_error(errno, boost::system::generic_category(),
-                                      "fstat");
+    DWARFS_THROW(system_error, "fstat");
   }
   return st.st_size;
 }
@@ -60,8 +59,7 @@ void* safe_mmap(int fd, size_t size) {
   void* addr = ::mmap(NULL, size, PROT_READ, MAP_PRIVATE, fd, 0);
 
   if (addr == MAP_FAILED) {
-    throw boost::system::system_error(errno, boost::system::generic_category(),
-                                      "mmap");
+    DWARFS_THROW(system_error, "mmap");
   }
 
   return addr;
diff --git a/src/dwarfs/options.cpp b/src/dwarfs/options.cpp
index f382f686..a20843ae 100644
--- a/src/dwarfs/options.cpp
+++ b/src/dwarfs/options.cpp
@@ -24,6 +24,7 @@
 
 #include <fmt/format.h>
 
+#include "dwarfs/error.h"
 #include "dwarfs/options.h"
 
 namespace dwarfs {
@@ -64,7 +65,7 @@ mlock_mode parse_mlock_mode(std::string_view mode) {
   if (mode == "must") {
     return mlock_mode::MUST;
   }
-  throw std::runtime_error(fmt::format("invalid lock mode: {}", mode));
+  DWARFS_THROW(error, fmt::format("invalid lock mode: {}", mode));
 }
 
 } // namespace dwarfs
diff --git a/src/dwarfs/os_access_posix.cpp b/src/dwarfs/os_access_posix.cpp
index b40ec2c6..a7193765 100644
--- a/src/dwarfs/os_access_posix.cpp
+++ b/src/dwarfs/os_access_posix.cpp
@@ -19,7 +19,6 @@
  * along with dwarfs.  If not, see <https://www.gnu.org/licenses/>.
  */
 
-#include <cerrno>
 #include <stdexcept>
 #include <vector>
 
@@ -27,8 +26,9 @@
 #include <sys/stat.h>
 #include <unistd.h>
 
-#include <boost/system/system_error.hpp>
+#include <fmt/format.h>
 
+#include "dwarfs/error.h"
 #include "dwarfs/mmap.h"
 #include "dwarfs/os_access_posix.h"
 
@@ -39,8 +39,7 @@ class posix_dir_reader : public dir_reader {
   posix_dir_reader(const std::string& path)
       : dir_(::opendir(path.c_str())) {
     if (!dir_) {
-      throw boost::system::system_error(
-          errno, boost::system::generic_category(), "opendir: " + path);
+      DWARFS_THROW(system_error, fmt::format("opendir('{}')", path));
     }
   }
 
@@ -64,8 +63,7 @@ class posix_dir_reader : public dir_reader {
       return false;
     }
 
-    throw boost::system::system_error(errno, boost::system::generic_category(),
-                                      "readdir_r");
+    DWARFS_THROW(system_error, "readdir");
   }
 
  private:
@@ -79,8 +77,7 @@ os_access_posix::opendir(const std::string& path) const {
 
 void os_access_posix::lstat(const std::string& path, struct ::stat* st) const {
   if (::lstat(path.c_str(), st) == -1) {
-    throw boost::system::system_error(errno, boost::system::generic_category(),
-                                      "lstat");
+    DWARFS_THROW(system_error, fmt::format("lstat('{}')", path));
   }
 }
 
@@ -93,8 +90,7 @@ os_access_posix::readlink(const std::string& path, size_t size) const {
     return std::string(linkname.begin(), linkname.end());
   }
 
-  throw boost::system::system_error(errno, boost::system::generic_category(),
-                                    "readlink");
+  DWARFS_THROW(system_error, fmt::format("readlink('{}')", path));
 }
 
 std::shared_ptr<mmif>
diff --git a/src/dwarfs/python_script.cpp b/src/dwarfs/python_script.cpp
index 840f02a7..e88b220a 100644
--- a/src/dwarfs/python_script.cpp
+++ b/src/dwarfs/python_script.cpp
@@ -31,6 +31,7 @@
 #include <fmt/format.h>
 
 #include "dwarfs/entry.h"
+#include "dwarfs/error.h"
 #include "dwarfs/inode.h"
 #include "dwarfs/logger.h"
 #include "dwarfs/options_interface.h"
@@ -282,7 +283,7 @@ python_script::impl::impl(logger& lgr, const std::string& code,
     has_order_ = has_callable(instance_, "order");
   } catch (py::error_already_set const&) {
     log_py_error();
-    throw std::runtime_error("error initializing script");
+    DWARFS_THROW(error, "error initializing script");
   }
 }
 
@@ -347,7 +348,7 @@ void python_script::impl::configure(options_interface const& oi) {
     instance_.attr("configure")(py::ptr(&oi));
   } catch (py::error_already_set const&) {
     log_py_error();
-    throw std::runtime_error("error in configure");
+    DWARFS_THROW(error, "error in configure");
   }
 }
 
@@ -358,7 +359,7 @@ bool python_script::impl::filter(entry_interface const& ei) {
         instance_.attr("filter")(std::make_shared<entry_wrapper>(ei)));
   } catch (py::error_already_set const&) {
     log_py_error();
-    throw std::runtime_error("error filtering entry");
+    DWARFS_THROW(error, "error filtering entry");
   }
 }
 
@@ -368,7 +369,7 @@ void python_script::impl::transform(entry_interface& ei) {
     instance_.attr("transform")(std::make_shared<mutable_entry_wrapper>(ei));
   } catch (py::error_already_set const&) {
     log_py_error();
-    throw std::runtime_error("error transforming entry");
+    DWARFS_THROW(error, "error transforming entry");
   }
 }
 
@@ -407,24 +408,23 @@ void python_script::impl::order(inode_vector& iv) {
     }
 
     if (index != iv.size()) {
-      throw std::runtime_error("order() returned different number of files");
+      DWARFS_THROW(error, "order() returned different number of files");
     }
 
-    std::sort(iv.begin(), iv.end(),
-              [&](inode_ptr const& a, inode_ptr const& b) {
-                auto ia = priority.find(a.get());
-                auto ib = priority.find(b.get());
-                if (ia == priority.end() || ib == priority.end()) {
-                  throw std::runtime_error(
-                      "invalid inode pointer while ordering files");
-                }
-                return ia->second < ib->second;
-              });
+    std::sort(
+        iv.begin(), iv.end(), [&](inode_ptr const& a, inode_ptr const& b) {
+          auto ia = priority.find(a.get());
+          auto ib = priority.find(b.get());
+          if (ia == priority.end() || ib == priority.end()) {
+            DWARFS_THROW(error, "invalid inode pointer while ordering files");
+          }
+          return ia->second < ib->second;
+        });
 
     td << "applied new inode order";
   } catch (py::error_already_set const&) {
     log_py_error();
-    throw std::runtime_error("error ordering inodes");
+    DWARFS_THROW(error, "error ordering inodes");
   }
 }
 
diff --git a/src/dwarfs/scanner.cpp b/src/dwarfs/scanner.cpp
index 4a791b4c..0a80fd79 100644
--- a/src/dwarfs/scanner.cpp
+++ b/src/dwarfs/scanner.cpp
@@ -40,6 +40,7 @@
 #include <fmt/format.h>
 
 #include "dwarfs/entry.h"
+#include "dwarfs/error.h"
 #include "dwarfs/filesystem_writer.h"
 #include "dwarfs/global_entry_data.h"
 #include "dwarfs/hash_util.h"
@@ -336,7 +337,7 @@ scanner_<LoggerPolicy>::scan_tree(const std::string& path, progress& prog) {
   auto root = entry_->create(*os_, path);
 
   if (root->type() != entry::E_DIR) {
-    throw std::runtime_error(path + " must be a directory");
+    DWARFS_THROW(error, fmt::format("'{}' must be a directory", path));
   }
 
   std::deque<std::shared_ptr<entry>> queue({root});
@@ -346,7 +347,7 @@ scanner_<LoggerPolicy>::scan_tree(const std::string& path, progress& prog) {
     auto parent = std::dynamic_pointer_cast<dir>(queue.front());
 
     if (!parent) {
-      throw std::runtime_error("expected directory");
+      DWARFS_THROW(error, "expected directory");
     }
 
     queue.pop_front();
diff --git a/src/dwarfs/util.cpp b/src/dwarfs/util.cpp
index 00b3110a..5ab8e220 100644
--- a/src/dwarfs/util.cpp
+++ b/src/dwarfs/util.cpp
@@ -21,13 +21,13 @@
 
 #include <array>
 #include <climits>
-#include <stdexcept>
 #include <string>
 
 #include <unistd.h>
 
 #include <folly/String.h>
 
+#include "dwarfs/error.h"
 #include "dwarfs/util.h"
 
 namespace dwarfs {
@@ -77,7 +77,7 @@ size_t parse_size_with_unit(const std::string& str) {
     }
   }
 
-  throw std::runtime_error("invalid size suffix");
+  DWARFS_THROW(error, "invalid size suffix");
 }
 
 std::string get_program_path() {
diff --git a/src/dwarfs/worker_group.cpp b/src/dwarfs/worker_group.cpp
index 3b5bb987..597508bb 100644
--- a/src/dwarfs/worker_group.cpp
+++ b/src/dwarfs/worker_group.cpp
@@ -24,7 +24,6 @@
 #include <cstdint>
 #include <mutex>
 #include <queue>
-#include <stdexcept>
 #include <string>
 #include <thread>
 #include <vector>
@@ -36,6 +35,7 @@
 #include <folly/Conv.h>
 #include <folly/system/ThreadName.h>
 
+#include "dwarfs/error.h"
 #include "dwarfs/semaphore.h"
 #include "dwarfs/worker_group.h"
 
@@ -52,7 +52,7 @@ class basic_worker_group : public worker_group::impl, private Policy {
       , pending_(0)
       , max_queue_len_(max_queue_len) {
     if (num_workers < 1) {
-      throw std::runtime_error("invalid number of worker threads");
+      DWARFS_THROW(error, "invalid number of worker threads");
     }
     if (!group_name) {
       group_name = "worker";
diff --git a/src/dwarfsck.cpp b/src/dwarfsck.cpp
index 0bfd5f35..d85a70a6 100644
--- a/src/dwarfsck.cpp
+++ b/src/dwarfsck.cpp
@@ -27,6 +27,7 @@
 #include <folly/String.h>
 #include <folly/json.h>
 
+#include "dwarfs/error.h"
 #include "dwarfs/filesystem_v2.h"
 #include "dwarfs/logger.h"
 #include "dwarfs/mmap.h"
@@ -65,25 +66,39 @@ int dwarfsck(int argc, char** argv) {
 
   po::variables_map vm;
 
-  po::store(
-      po::command_line_parser(argc, argv).options(opts).positional(pos).run(),
-      vm);
-  po::notify(vm);
+  try {
+    po::store(
+        po::command_line_parser(argc, argv).options(opts).positional(pos).run(),
+        vm);
+    po::notify(vm);
+  } catch (po::error const& e) {
+    std::cerr << "error: " << e.what() << std::endl;
+    return 1;
+  }
 
   if (vm.count("help") or !vm.count("input")) {
     std::cout << "dwarfsck (" << DWARFS_VERSION << ")\n" << opts << std::endl;
     return 0;
   }
 
-  dwarfs::stream_logger lgr(std::cerr, logger::parse_level(log_level));
+  stream_logger lgr(std::cerr, logger::parse_level(log_level));
+  log_proxy<debug_logger_policy> log(lgr);
 
-  auto mm = std::make_shared<dwarfs::mmap>(input);
+  try {
+    auto mm = std::make_shared<mmap>(input);
 
-  if (json) {
-    dwarfs::filesystem_v2 fs(lgr, mm);
-    std::cout << folly::toPrettyJson(fs.metadata_as_dynamic()) << std::endl;
-  } else {
-    dwarfs::filesystem_v2::identify(lgr, mm, std::cout, detail);
+    if (json) {
+      filesystem_v2 fs(lgr, mm);
+      std::cout << folly::toPrettyJson(fs.metadata_as_dynamic()) << std::endl;
+    } else {
+      filesystem_v2::identify(lgr, mm, std::cout, detail);
+    }
+  } catch (system_error const& e) {
+    log.error() << folly::exceptionStr(e);
+    return 1;
+  } catch (error const& e) {
+    log.error() << folly::exceptionStr(e);
+    return 1;
   }
 
   return 0;
@@ -92,10 +107,5 @@ int dwarfsck(int argc, char** argv) {
 } // namespace dwarfs
 
 int main(int argc, char** argv) {
-  try {
-    return dwarfs::dwarfsck(argc, argv);
-  } catch (std::exception const& e) {
-    std::cerr << "ERROR: " << folly::exceptionStr(e) << std::endl;
-    return 1;
-  }
+  return dwarfs::safe_main([&] { return dwarfs::dwarfsck(argc, argv); });
 }
diff --git a/src/mkdwarfs.cpp b/src/mkdwarfs.cpp
index 6dddc7e8..4eb99bbc 100644
--- a/src/mkdwarfs.cpp
+++ b/src/mkdwarfs.cpp
@@ -45,7 +45,6 @@
 
 #include <folly/Conv.h>
 #include <folly/FileUtil.h>
-#include <folly/experimental/symbolizer/SignalHandler.h>
 #include <folly/gen/String.h>
 
 #include <fmt/format.h>
@@ -58,6 +57,7 @@
 #include "dwarfs/block_manager.h"
 #include "dwarfs/console_writer.h"
 #include "dwarfs/entry.h"
+#include "dwarfs/error.h"
 #include "dwarfs/filesystem_v2.h"
 #include "dwarfs/filesystem_writer.h"
 #include "dwarfs/logger.h"
@@ -401,17 +401,24 @@ int mkdwarfs(int argc, char** argv) {
   // clang-format on
 
   po::variables_map vm;
-  auto parsed = po::parse_command_line(argc, argv, opts);
 
-  po::store(parsed, vm);
-  po::notify(vm);
+  try {
+    auto parsed = po::parse_command_line(argc, argv, opts);
 
-  auto unrecognized =
-      po::collect_unrecognized(parsed.options, po::include_positional);
+    po::store(parsed, vm);
+    po::notify(vm);
 
-  if (!unrecognized.empty()) {
-    throw std::runtime_error("unrecognized argument(s): " +
-                             boost::join(unrecognized, " "));
+    auto unrecognized =
+        po::collect_unrecognized(parsed.options, po::include_positional);
+
+    if (!unrecognized.empty()) {
+      std::cerr << "error: unrecognized argument(s) '"
+                << boost::join(unrecognized, " ") << "'" << std::endl;
+      return 1;
+    }
+  } catch (po::error const& e) {
+    std::cerr << "error: " << e.what() << std::endl;
+    return 1;
   }
 
   if (vm.count("help") or !vm.count("input") or !vm.count("output")) {
@@ -478,7 +485,8 @@ int mkdwarfs(int argc, char** argv) {
   }
 
   if (level >= levels.size()) {
-    throw std::runtime_error("invalid compression level");
+    std::cerr << "error: invalid compression level" << std::endl;
+    return 1;
   }
 
   auto const& defaults = levels[level];
@@ -509,36 +517,59 @@ int mkdwarfs(int argc, char** argv) {
 
   std::vector<std::string> order_opts;
   boost::split(order_opts, order, boost::is_any_of(":"));
+
   if (auto it = order_choices.find(order_opts.front());
       it != order_choices.end()) {
     options.file_order.mode = it->second;
+
     if (order_opts.size() > 1) {
       if (options.file_order.mode != file_order_mode::NILSIMSA) {
-        throw std::runtime_error(
-            fmt::format("inode order mode '{}' does not support options",
-                        order_opts.front()));
+        std::cerr << "error: inode order mode '" << order_opts.front()
+                  << "' does not support options" << std::endl;
+        return 1;
       }
+
       if (order_opts.size() > 3) {
-        throw std::runtime_error(fmt::format(
-            "too many options for inode order mode '{}'", order_opts.front()));
+        std::cerr << "error: too many options for inode order mode '"
+                  << order_opts[0] << "'" << std::endl;
+        return 1;
       }
-      options.file_order.nilsimsa_limit = folly::to<int>(order_opts[1]);
-      if (options.file_order.nilsimsa_limit < 0 ||
-          options.file_order.nilsimsa_limit > 255) {
-        throw std::runtime_error(
-            fmt::format("limit ({}) out of range for '{}' (0..255)",
-                        options.file_order.nilsimsa_limit, order_opts.front()));
+
+      if (auto val = folly::tryTo<int>(order_opts[1])) {
+        options.file_order.nilsimsa_limit = *val;
+        if (options.file_order.nilsimsa_limit < 0 ||
+            options.file_order.nilsimsa_limit > 255) {
+          std::cerr << "error: limit (" << order_opts[1]
+                    << ") out of range for order '" << order_opts[0]
+                    << "' (0..255)" << std::endl;
+          return 1;
+        }
+      } else {
+        std::cerr << "error: limit (" << order_opts[1]
+                  << ") is not numeric for order '" << order_opts[0] << "'"
+                  << std::endl;
+        return 1;
       }
+
       if (order_opts.size() > 2) {
-        options.file_order.nilsimsa_depth = folly::to<int>(order_opts[2]);
-        if (options.file_order.nilsimsa_depth < 0) {
-          throw std::runtime_error(fmt::format(
-              "depth ({}) cannot be negative for '{}'", order_opts.front()));
+        if (auto val = folly::tryTo<int>(order_opts[2])) {
+          options.file_order.nilsimsa_depth = *val;
+          if (options.file_order.nilsimsa_depth < 0) {
+            std::cerr << "error: depth (" << order_opts[2]
+                      << ") cannot be negative for order '" << order_opts[0]
+                      << "'" << std::endl;
+          }
+        } else {
+          std::cerr << "error: depth (" << order_opts[2]
+                    << ") is not numeric for order '" << order_opts[0] << "'"
+                    << std::endl;
+          return 1;
         }
       }
     }
   } else {
-    throw std::runtime_error("invalid inode order mode: " + order);
+    std::cerr << "error: invalid inode order mode: " << order << std::endl;
+    return 1;
   }
 
   size_t mem_limit = parse_size_with_unit(memory_limit);
@@ -548,11 +579,17 @@ int mkdwarfs(int argc, char** argv) {
   if (window_sizes != "-") {
     boost::split(wsv, window_sizes, boost::is_any_of(","));
 
-    std::transform(wsv.begin(), wsv.end(),
-                   std::back_inserter(cfg.blockhash_window_size),
-                   [](const std::string& x) {
-                     return static_cast<size_t>(1) << folly::to<unsigned>(x);
-                   });
+    try {
+      std::transform(wsv.begin(), wsv.end(),
+                     std::back_inserter(cfg.blockhash_window_size),
+                     [](const std::string& x) {
+                       return static_cast<size_t>(1) << folly::to<unsigned>(x);
+                     });
+    } catch (folly::ConversionError const& e) {
+      std::cerr << "error: window size is not numeric (" << window_sizes << ")"
+                << std::endl;
+      return 1;
+    }
   }
 
   worker_group wg_writer("writer", num_workers);
@@ -566,7 +603,9 @@ int mkdwarfs(int argc, char** argv) {
     progress_mode = "simple";
   }
   if (!progress_modes.count(progress_mode)) {
-    throw std::runtime_error("invalid progress mode: " + progress_mode);
+    std::cerr << "error: invalid progress mode '" << progress_mode << "'"
+              << std::endl;
+    return 1;
   }
 
   auto pg_mode = progress_modes.at(progress_mode);
@@ -594,7 +633,8 @@ int mkdwarfs(int argc, char** argv) {
     if (folly::readFile(file.c_str(), code)) {
       script = std::make_shared<python_script>(lgr, code, ctor);
     } else {
-      throw std::runtime_error("could not load script: " + file);
+      std::cerr << "error: could not load script '" << file << "'" << std::endl;
+      return 1;
     }
   }
 #endif
@@ -607,8 +647,10 @@ int mkdwarfs(int argc, char** argv) {
   }
 
   if (options.file_order.mode == file_order_mode::SCRIPT && !script) {
-    throw std::runtime_error(
-        "--order=script can only be used with a valid --script option");
+    std::cerr << "error: '--order=script' can only be used with a valid "
+                 "'--script' option"
+              << std::endl;
+    return 1;
   }
 
   if (vm.count("set-owner")) {
@@ -620,18 +662,32 @@ int mkdwarfs(int argc, char** argv) {
   }
 
   if (vm.count("set-time")) {
-    options.timestamp = timestamp == "now" ? std::time(nullptr)
-                                           : folly::to<uint64_t>(timestamp);
+    if (timestamp == "now") {
+      options.timestamp = std::time(nullptr);
+    } else if (auto val = folly::tryTo<uint64_t>(timestamp)) {
+      options.timestamp = *val;
+    } else {
+      std::cerr
+          << "error: argument for option '--set-time' must be numeric or `now`"
+          << std::endl;
+      return 1;
+    }
   }
 
   if (auto it = time_resolutions.find(time_resolution);
       it != time_resolutions.end()) {
     options.time_resolution_sec = it->second;
-  } else {
-    options.time_resolution_sec = folly::to<uint32_t>(time_resolution);
+  } else if (auto val = folly::tryTo<uint32_t>(time_resolution)) {
+    options.time_resolution_sec = *val;
     if (options.time_resolution_sec == 0) {
-      throw std::runtime_error("timestamp resolution cannot be 0");
+      std::cerr << "error: the argument to '--time-resolution' must be nonzero"
+                << std::endl;
+      return 1;
     }
+  } else {
+    std::cerr << "error: the argument ('" << time_resolution
+              << "') to '--time-resolution' is invalid" << std::endl;
+    return 1;
   }
 
   unsigned interval_ms =
@@ -639,6 +695,14 @@ int mkdwarfs(int argc, char** argv) {
           ? 2000
           : 200;
 
+  std::ofstream ofs(output, std::ios::binary);
+
+  if (ofs.bad() || !ofs.is_open()) {
+    std::cerr << "error: cannot open output file '" << output
+              << "': " << strerror(errno) << std::endl;
+    return 1;
+  }
+
   log_proxy<debug_logger_policy> log(lgr);
 
   progress prog([&](const progress& p, bool last) { lgr.update(p, last); },
@@ -648,22 +712,15 @@ int mkdwarfs(int argc, char** argv) {
   block_compressor schema_bc(schema_compression);
   block_compressor metadata_bc(metadata_compression);
 
-  std::ofstream ofs(output, std::ios::binary);
-
-  if (ofs.bad() || !ofs.is_open()) {
-    throw std::runtime_error(
-        fmt::format("cannot open '{}': {}", output, strerror(errno)));
-  }
-
   filesystem_writer fsw(ofs, lgr, wg_writer, prog, bc, schema_bc, metadata_bc,
                         mem_limit);
 
+  auto ti = log.timed_info();
+
   if (recompress) {
-    auto ti = log.timed_info();
     filesystem_v2::rewrite(lgr, prog, std::make_shared<dwarfs::mmap>(path),
                            fsw);
     wg_writer.wait();
-    ti << "filesystem rewritten";
   } else {
     options.inode.with_similarity =
         force_similarity ||
@@ -674,44 +731,41 @@ int mkdwarfs(int argc, char** argv) {
     scanner s(lgr, wg_scanner, cfg, entry_factory::create(),
               std::make_shared<os_access_posix>(), std::move(script), options);
 
-    {
-      auto ti = log.timed_info();
-
+    try {
       s.scan(fsw, path, prog);
-
-      std::ostringstream err;
-
-      if (prog.errors) {
-        err << "with " << prog.errors << " error";
-        if (prog.errors > 1) {
-          err << "s";
-        }
-      } else {
-        err << "without errors";
-      }
-
-      ti << "filesystem created " << err.str();
+    } catch (error const& e) {
+      log.error() << e.what();
+      prog.errors++;
+      return 1;
     }
   }
 
   ofs.close();
 
   if (ofs.bad()) {
-    throw std::runtime_error(
-        fmt::format("failed to close '{}': {}", output, strerror(errno)));
+    log.error() << "failed to close output file '" << output
+                << "': " << strerror(errno);
+    return 1;
   }
 
+  std::ostringstream err;
+
+  if (prog.errors) {
+    err << "with " << prog.errors << " error";
+    if (prog.errors > 1) {
+      err << "s";
+    }
+  } else {
+    err << "without errors";
+  }
+
+  ti << "filesystem " << (recompress ? "rewritten" : "created ") << err.str();
+
   return prog.errors > 0;
 }
 
 } // namespace
 
 int main(int argc, char** argv) {
-  try {
-    folly::symbolizer::installFatalSignalHandler();
-    return mkdwarfs(argc, argv);
-  } catch (std::exception const& e) {
-    std::cerr << "ERROR: " << folly::exceptionStr(e) << std::endl;
-    return 1;
-  }
+  return dwarfs::safe_main([&] { return mkdwarfs(argc, argv); });
 }