Improved IO error checking.

Makefile

@@ -36,7 +36,7 @@ endif
 	$(MAKE) -C doc $@
 
 
-ifneq ($(wildcard .hg/data/.),)
+ifneq ($(wildcard .hg/.),)
 # automatically generate ChangeLog from local Mercurial repo
 ChangeLog:
 	hg log --style=changelog > $@

src/file.cpp

@@ -88,7 +88,7 @@ FileBase::~FileBase()
 }
 
 
-void FileBase::sopen()
+bool FileBase::do_sopen()
 {
     if (_shflags < 0)
         _fd = ::open(_name, _flags, _mode);
@@ -101,13 +101,15 @@ void FileBase::sopen()
 #elif defined(SH_DENYRW)
         _fd = ::sopen(_name, _flags, _shflags, _mode);
 #else
-        assert(0);
+        throwInternalError("bad usage of do_sopen()");
 #endif
     }
-    if (!(_fd < 0)) {
-        ::fstat(_fd, &st);
-        _length = st.st_size;
-    }
+    if (_fd < 0)
+        return false;
+    if (::fstat(_fd, &st) != 0)
+        throwIOException(_name, errno);
+    _length = st.st_size;
+    return true;
 }
 
 
@@ -232,8 +234,7 @@ void InputFile::sopen(const char *name, int flags, int shflags)
     _mode = 0;
     _offset = 0;
     _length = 0;
-    FileBase::sopen();
-    if (!isOpen())
+    if (!FileBase::do_sopen())
     {
         if (errno == ENOENT)
             throw FileNotFoundException(_name, errno);
@@ -318,8 +319,7 @@ void OutputFile::sopen(const char *name, int flags, int shflags, int mode)
     _mode = mode;
     _offset = 0;
     _length = 0;
-    FileBase::sopen();
-    if (!isOpen())
+    if (!FileBase::do_sopen())
     {
 #if 0
         // don't throw FileNotFound here -- this is confusing
@@ -366,7 +366,8 @@ off_t OutputFile::st_size() const
         return bytes_written;  // too big if seek()+write() instead of rewrite()
     }
     struct stat my_st;
-    ::fstat(_fd, &my_st);
+    if (::fstat(_fd, &my_st) != 0)
+        throwIOException(_name, errno);
     return my_st.st_size;
 }
 
@@ -402,15 +403,19 @@ void OutputFile::set_extent(off_t offset, off_t length)
     super::set_extent(offset, length);
     bytes_written = 0;
     if (0==offset && (off_t)~0u==length) {
-        ::fstat(_fd, &st);
+        if (::fstat(_fd, &st) != 0)
+            throwIOException(_name, errno);
         _length = st.st_size - offset;
     }
 }
 
 off_t OutputFile::unset_extent()
 {
+    off_t l = ::lseek(_fd, 0, SEEK_END);
+    if (l < 0)
+        throwIOException("lseek error", errno);
     _offset = 0;
-    _length = ::lseek(_fd, 0, SEEK_END);
+    _length = l;
     bytes_written = _length;
     return _length;
 }

src/file.h

@@ -63,7 +63,7 @@ public:
     virtual void set_extent(off_t offset, off_t length);
 
 protected:
-    void sopen();
+    bool do_sopen();
     virtual int read(void *buf, int len);
     virtual int readx(void *buf, int len);
     virtual void write(const void *buf, int len);

src/work.cpp

@@ -51,6 +51,9 @@
 #  define SH_DENYWR     (-1)
 #endif
 
+// ignore errors in some cases and silence __attribute__((__warn_unused_result__))
+#define IGNORE_ERROR(var)        ACC_UNUSED(var)
+
 
 /*************************************************************************
 // process one file
@@ -98,8 +101,13 @@ void do_one_file(const char *iname, char *oname)
     fi.sopen(iname, O_RDONLY | O_BINARY, SH_DENYWR);
 
 #if defined(USE_FTIME)
-    struct ftime fit;
-    getftime(fi.getFd(),&fit);
+    struct ftime fi_ftime;
+    memset(&fi_ftime, 0, sizeof(fi_ftime));
+    if (opt->preserve_timestamp)
+    {
+        if (getftime(fi.getFd(), &fi_ftime) != 0)
+            throwIOException("cannot determine file timestamp");
+    }
 #endif
 
     // open output file
@@ -124,9 +132,11 @@ void do_one_file(const char *iname, char *oname)
             if (opt->force >= 2)
             {
 #if defined(HAVE_CHMOD)
-                (void) ::chmod(tname, 0777);
+                r = chmod(tname, 0777);
+                IGNORE_ERROR(r);
 #endif
-                (void) ::unlink(tname);
+                r = unlink(tname);
+                IGNORE_ERROR(r);
             }
             int flags = O_CREAT | O_WRONLY | O_BINARY;
             if (opt->force)
@@ -165,15 +175,17 @@ void do_one_file(const char *iname, char *oname)
         throwInternalError("invalid command");
 
     // copy time stamp
-    if (oname[0] && fo.isOpen())
+    if (opt->preserve_timestamp && oname[0] && fo.isOpen())
     {
 #if defined(USE_FTIME)
-        setftime(fo.getFd(),&fit);
+        r = setftime(fo.getFd(), &fi_ftime);
+        IGNORE_ERROR(r);
 #elif defined(USE__FUTIME)
         struct _utimbuf u;
         u.actime = st.st_atime;
         u.modtime = st.st_mtime;
-        (void) _futime(fo.getFd(),&u);
+        r = _futime(fo.getFd(), &u);
+        IGNORE_ERROR(r);
 #endif
     }
 
@@ -188,7 +200,8 @@ void do_one_file(const char *iname, char *oname)
         if (!opt->backup)
         {
 #if defined(HAVE_CHMOD)
-            (void) ::chmod(iname, 0777);
+            r = chmod(iname, 0777);
+            IGNORE_ERROR(r);
 #endif
             File::unlink(iname);
         }
@@ -217,7 +230,7 @@ void do_one_file(const char *iname, char *oname)
             u.actime = st.st_atime;
             u.modtime = st.st_mtime;
             r = utime(name, &u);
-            UNUSED(r);
+            IGNORE_ERROR(r);
         }
 #endif
 #if defined(HAVE_CHMOD)
@@ -225,7 +238,7 @@ void do_one_file(const char *iname, char *oname)
         if (opt->preserve_mode)
         {
             r = chmod(name, st.st_mode);
-            UNUSED(r);
+            IGNORE_ERROR(r);
         }
 #endif
 #if defined(HAVE_CHOWN)
@@ -233,7 +246,7 @@ void do_one_file(const char *iname, char *oname)
         if (opt->preserve_ownership)
         {
             r = chown(name, st.st_uid, st.st_gid);
-            UNUSED(r);
+            IGNORE_ERROR(r);
         }
 #endif
     }
@@ -251,9 +264,11 @@ static void unlink_ofile(char *oname)
     if (oname && oname[0])
     {
 #if defined(HAVE_CHMOD)
-        (void) ::chmod(oname, 0777);
+        int r;
+        r = chmod(oname, 0777);
+        IGNORE_ERROR(r);
 #endif
-        if (::unlink(oname) == 0)
+        if (unlink(oname) == 0)
             oname[0] = 0;
     }
 }