Properly catch exceptions in {i|o}stream

Fixes microsoft#1858
miscco · Jul 1, 2021 · 3c59e25 · 3c59e25
1 parent e745bad
commit 3c59e25
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Showing 5 changed files with 146 additions and 16 deletions.
diff --git a/stl/inc/istream b/stl/inc/istream
@@ -619,14 +619,12 @@ public:
             return -1;
         }
 
-        bool _Sync_failed = true; // sync fails if an exception is thrown
         _TRY_IO_BEGIN
-        _Sync_failed = _Rdbuf->pubsync() == -1;
-        _CATCH_IO_END
-        if (_Sync_failed) {
+        if (_Rdbuf->pubsync() == -1) {
             _Myios::setstate(ios_base::badbit);
             return -1;
         }
+        _CATCH_IO_END
 
         return 0;
     }
@@ -637,8 +635,12 @@ public:
         _Myios::clear(_Oldstate & ~ios_base::eofbit);
         const sentry _Ok(*this, true);
 
-        if (!this->fail() && static_cast<off_type>(_Myios::rdbuf()->pubseekpos(_Pos, ios_base::in)) == -1) {
-            _Myios::setstate(_State | ios_base::failbit);
+        if (!this->fail()) {
+            _TRY_IO_BEGIN
+            if (static_cast<off_type>(_Myios::rdbuf()->pubseekpos(_Pos, ios_base::in)) == -1) {
+                _Myios::setstate(_State | ios_base::failbit);
+            }
+            _CATCH_IO_END
         }
 
         return *this;
@@ -651,8 +653,12 @@ public:
         _Myios::clear(_Oldstate & ~ios_base::eofbit);
         const sentry _Ok(*this, true);
 
-        if (!this->fail() && static_cast<off_type>(_Myios::rdbuf()->pubseekoff(_Off, _Way, ios_base::in)) == -1) {
-            _Myios::setstate(_State | ios_base::failbit);
+        if (!this->fail()) {
+            _TRY_IO_BEGIN
+            if (static_cast<off_type>(_Myios::rdbuf()->pubseekoff(_Off, _Way, ios_base::in)) == -1) {
+                _Myios::setstate(_State | ios_base::failbit);
+            }
+            _CATCH_IO_END
         }
 
         return *this;
@@ -662,10 +668,12 @@ public:
         const sentry _Ok(*this, true);
 
         if (!this->fail()) {
+            _TRY_IO_BEGIN
             return _Myios::rdbuf()->pubseekoff(0, ios_base::cur, ios_base::in);
-        } else {
-            return pos_type(-1);
+            _CATCH_IO_END
         }
+
+        return pos_type(-1);
     }
 
 private:

diff --git a/stl/inc/ostream b/stl/inc/ostream
@@ -547,18 +547,24 @@ public:
         if (_Rdbuf) { // buffer exists, flush it
             const sentry _Ok(*this);
 
+            _TRY_IO_BEGIN
             if (_Ok && _Rdbuf->pubsync() == -1) {
                 _Myios::setstate(ios_base::badbit); // sync failed
             }
+            _CATCH_IO_END
         }
         return *this;
     }
 
     basic_ostream& __CLR_OR_THIS_CALL seekp(pos_type _Pos) { // set output stream position to _Pos
         const sentry _Ok(*this);
 
-        if (!this->fail() && static_cast<off_type>(_Myios::rdbuf()->pubseekpos(_Pos, ios_base::out)) == -1) {
-            _Myios::setstate(ios_base::failbit);
+        if (!this->fail()) {
+            _TRY_IO_BEGIN
+            if (static_cast<off_type>(_Myios::rdbuf()->pubseekpos(_Pos, ios_base::out)) == -1) {
+                _Myios::setstate(ios_base::failbit);
+            }
+            _CATCH_IO_END
         }
 
         return *this;
@@ -568,8 +574,12 @@ public:
         off_type _Off, ios_base::seekdir _Way) { // change output stream position by _Off, according to _Way
         const sentry _Ok(*this);
 
-        if (!this->fail() && static_cast<off_type>(_Myios::rdbuf()->pubseekoff(_Off, _Way, ios_base::out)) == -1) {
-            _Myios::setstate(ios_base::failbit);
+        if (!this->fail()) {
+            _TRY_IO_BEGIN
+            if (static_cast<off_type>(_Myios::rdbuf()->pubseekoff(_Off, _Way, ios_base::out)) == -1) {
+                _Myios::setstate(ios_base::failbit);
+            }
+            _CATCH_IO_END
         }
 
         return *this;
@@ -579,10 +589,12 @@ public:
         const sentry _Ok(*this);
 
         if (!this->fail()) {
+            _TRY_IO_BEGIN
             return _Myios::rdbuf()->pubseekoff(0, ios_base::cur, ios_base::out);
-        } else {
-            return pos_type(-1);
+            _CATCH_IO_END
         }
+
+        return pos_type(-1);
     }
 };
 

diff --git a/tests/std/test.lst b/tests/std/test.lst
@@ -175,6 +175,7 @@ tests\GH_001411_core_headers
 tests\GH_001530_binomial_accuracy
 tests\GH_001541_case_sensitive_boolalpha
 tests\GH_001638_dllexport_derived_classes
+tests\GH_001858_iostream_exception
 tests\LWG2597_complex_branch_cut
 tests\LWG3018_shared_ptr_function
 tests\P0019R8_atomic_ref

diff --git a/tests/std/tests/GH_001858_iostream_exception/env.lst b/tests/std/tests/GH_001858_iostream_exception/env.lst
@@ -0,0 +1,4 @@
+# Copyright (c) Microsoft Corporation.
+# SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+
+RUNALL_INCLUDE ..\usual_matrix.lst
diff --git a/tests/std/tests/GH_001858_iostream_exception/test.cpp b/tests/std/tests/GH_001858_iostream_exception/test.cpp
@@ -0,0 +1,105 @@
+// Copyright (c) Microsoft Corporation.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+// Copyright (c) Microsoft Corporation.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+
+#include <cassert>
+#include <istream>
+#include <ostream>
+
+using namespace std;
+
+template <class CharT>
+class throwing_buffer : public basic_streambuf<CharT> {
+public:
+    streampos seekoff(streamoff, ios::seekdir, ios_base::openmode = ios_base::in | ios_base::out) override {
+        throw 42;
+    }
+
+    streampos seekpos(streampos, ios_base::openmode = ios_base::in | ios_base::out) override {
+        throw 42;
+    }
+
+    int sync() override {
+        throw 42;
+    }
+
+    basic_streambuf<CharT>* to_buf() {
+        return this;
+    }
+};
+
+template <class CharT>
+void test_istream_exceptions() {
+    throwing_buffer<CharT> buffer;
+
+    { // sync
+        basic_istream<CharT> is(buffer.to_buf());
+        assert(!is.bad());
+        is.sync();
+        assert(is.bad());
+    }
+
+    { // seekg
+        basic_istream<CharT> is(buffer.to_buf());
+        assert(!is.bad());
+        is.seekg(0);
+        assert(is.bad());
+    }
+
+    { // seekg
+        basic_istream<CharT> is(buffer.to_buf());
+        assert(!is.bad());
+        is.seekg(0, ios_base::beg);
+        assert(is.bad());
+    }
+
+    { // tellg
+        basic_istream<CharT> is(buffer.to_buf());
+        assert(!is.bad());
+        is.tellg();
+        assert(is.bad());
+    }
+}
+
+
+template <class CharT>
+void test_ostream_exceptions() {
+    throwing_buffer<CharT> buffer;
+
+    { // flush
+        basic_ostream<CharT> os(buffer.to_buf());
+        assert(!os.bad());
+        os.flush();
+        assert(os.bad());
+    }
+
+    { // seekp
+        basic_ostream<CharT> os(buffer.to_buf());
+        assert(!os.bad());
+        os.seekp(0);
+        assert(os.bad());
+    }
+
+    { // seekp
+        basic_ostream<CharT> os(buffer.to_buf());
+        assert(!os.bad());
+        os.seekp(0, ios_base::beg);
+        assert(os.bad());
+    }
+
+    { // tellp
+        basic_ostream<CharT> os(buffer.to_buf());
+        assert(!os.bad());
+        os.tellp();
+        assert(os.bad());
+    }
+}
+
+int main() {
+    test_istream_exceptions<char>();
+    test_istream_exceptions<wchar_t>();
+
+    test_ostream_exceptions<char>();
+    test_ostream_exceptions<wchar_t>();
+}