fileutl: empty file support: Avoid fstat() on -1 fd and check result

[apt.git] / apt-pkg / contrib / fileutl.cc

diff --git a/apt-pkg/contrib/fileutl.cc b/apt-pkg/contrib/fileutl.cc
index e410f52d6f892e3648e1655cb2b81d9c1ec3c12b..fd13b45dc61374f6534524becda29e7bce488b0a 100644 (file)
--- a/apt-pkg/contrib/fileutl.cc
+++ b/apt-pkg/contrib/fileutl.cc
@@ -694,6 +694,25 @@ string flAbsPath(string File)
    return AbsPath;
 }
                                                                        /*}}}*/
+std::string flNormalize(std::string file)                              /*{{{*/
+{
+   if (file.empty())
+      return file;
+   // do some normalisation by removing // and /./ from the path
+   size_t found = string::npos;
+   while ((found = file.find("/./")) != string::npos)
+      file.replace(found, 3, "/");
+   while ((found = file.find("//")) != string::npos)
+      file.replace(found, 2, "/");
+
+   if (APT::String::Startswith(file, "/dev/null"))
+   {
+      file.erase(strlen("/dev/null"));
+      return file;
+   }
+   return file;
+}
+                                                                       /*}}}*/
 // SetCloseExec - Set the close on exec flag                           /*{{{*/
 // ---------------------------------------------------------------------
 /* */
@@ -1258,9 +1277,8 @@ public:
 
         writebuffer.bufferstart += written;
       }
-
       writebuffer.reset();
-      return true;
+      return wrapped->InternalFlush();
    }
    virtual ssize_t InternalWrite(void const * const From, unsigned long long const Size) APT_OVERRIDE
    {
@@ -1890,11 +1908,12 @@ public:
               " but was forced to ignore it in favor of an external binary – which isn't installed.", compressor.Name.c_str());
 
       bool const Comp = (Mode & FileFd::WriteOnly) == FileFd::WriteOnly;
-      if (Comp == false)
+      if (Comp == false && filefd->iFd != -1)
       {
         // Handle 'decompression' of empty files
         struct stat Buf;
-        fstat(filefd->iFd, &Buf);
+        if (fstat(filefd->iFd, &Buf) != 0)
+           return filefd->FileFdErrno("fstat", "Could not stat fd %d for file %s", filefd->iFd, filefd->FileName.c_str());
         if (Buf.st_size == 0 && S_ISFIFO(Buf.st_mode) == false)
            return true;
 
@@ -2383,7 +2402,7 @@ FileFd::~FileFd()
    gracefully. */
 bool FileFd::Read(void *To,unsigned long long Size,unsigned long long *Actual)
 {
-   if (d == nullptr)
+   if (d == nullptr || Failed())
       return false;
    ssize_t Res = 1;
    errno = 0;
@@ -2425,6 +2444,37 @@ bool FileFd::Read(void *To,unsigned long long Size,unsigned long long *Actual)
    }
 
    return FileFdError(_("read, still have %llu to read but none left"), Size);
+}
+bool FileFd::Read(int const Fd, void *To, unsigned long long Size, unsigned long long * const Actual)
+{
+   ssize_t Res = 1;
+   errno = 0;
+   if (Actual != nullptr)
+      *Actual = 0;
+   *static_cast<char *>(To) = '\0';
+   while (Res > 0 && Size > 0)
+   {
+      Res = read(Fd, To, Size);
+      if (Res < 0)
+      {
+        if (errno == EINTR)
+        {
+           Res = 1;
+           errno = 0;
+           continue;
+        }
+        return _error->Errno("read", _("Read error"));
+      }
+      To = static_cast<char *>(To) + Res;
+      Size -= Res;
+      if (Actual != 0)
+        *Actual += Res;
+   }
+   if (Size == 0)
+      return true;
+   if (Actual != nullptr)
+      return true;
+   return _error->Error(_("read, still have %llu to read but none left"), Size);
 }
                                                                        /*}}}*/
 // FileFd::ReadLine - Read a complete line from the file               /*{{{*/
@@ -2434,7 +2484,7 @@ bool FileFd::Read(void *To,unsigned long long Size,unsigned long long *Actual)
 char* FileFd::ReadLine(char *To, unsigned long long const Size)
 {
    *To = '\0';
-   if (d == nullptr)
+   if (d == nullptr || Failed())
       return nullptr;
    return d->InternalReadLine(To, Size);
 }
@@ -2442,6 +2492,8 @@ char* FileFd::ReadLine(char *To, unsigned long long const Size)
 // FileFd::Flush - Flush the file                                      /*{{{*/
 bool FileFd::Flush()
 {
+   if (Failed())
+      return false;
    if (d == nullptr)
       return true;
 
@@ -2451,7 +2503,7 @@ bool FileFd::Flush()
 // FileFd::Write - Write to the file                                   /*{{{*/
 bool FileFd::Write(const void *From,unsigned long long Size)
 {
-   if (d == nullptr)
+   if (d == nullptr || Failed())
       return false;
    ssize_t Res = 1;
    errno = 0;
@@ -2507,7 +2559,7 @@ bool FileFd::Write(int Fd, const void *From, unsigned long long Size)
 // FileFd::Seek - Seek in the file                                     /*{{{*/
 bool FileFd::Seek(unsigned long long To)
 {
-   if (d == nullptr)
+   if (d == nullptr || Failed())
       return false;
    Flags &= ~HitEof;
    return d->InternalSeek(To);
@@ -2516,7 +2568,7 @@ bool FileFd::Seek(unsigned long long To)
 // FileFd::Skip - Skip over data in the file                           /*{{{*/
 bool FileFd::Skip(unsigned long long Over)
 {
-   if (d == nullptr)
+   if (d == nullptr || Failed())
       return false;
    return d->InternalSkip(Over);
 }
@@ -2524,7 +2576,7 @@ bool FileFd::Skip(unsigned long long Over)
 // FileFd::Truncate - Truncate the file                                        /*{{{*/
 bool FileFd::Truncate(unsigned long long To)
 {
-   if (d == nullptr)
+   if (d == nullptr || Failed())
       return false;
    // truncating /dev/null is always successful - as we get an error otherwise
    if (To == 0 && FileName == "/dev/null")
@@ -2537,7 +2589,7 @@ bool FileFd::Truncate(unsigned long long To)
 /* */
 unsigned long long FileFd::Tell()
 {
-   if (d == nullptr)
+   if (d == nullptr || Failed())
       return false;
    off_t const Res = d->InternalTell();
    if (Res == (off_t)-1)
@@ -2600,7 +2652,7 @@ time_t FileFd::ModificationTime()
 unsigned long long FileFd::Size()
 {
    if (d == nullptr)
-      return false;
+      return 0;
    return d->InternalSize();
 }
                                                                        /*}}}*/
@@ -2664,13 +2716,12 @@ bool FileFd::FileFdErrno(const char *Function, const char *Description,...)
    va_list args;
    size_t msgSize = 400;
    int const errsv = errno;
-   while (true)
-   {
+   bool retry;
+   do {
       va_start(args,Description);
-      if (_error->InsertErrno(GlobalError::ERROR, Function, Description, args, errsv, msgSize) == false)
-        break;
+      retry = _error->InsertErrno(GlobalError::ERROR, Function, Description, args, errsv, msgSize);
       va_end(args);
-   }
+   } while (retry);
    return false;
 }
                                                                        /*}}}*/
@@ -2679,13 +2730,12 @@ bool FileFd::FileFdError(const char *Description,...) {
    Flags |= Fail;
    va_list args;
    size_t msgSize = 400;
-   while (true)
-   {
+   bool retry;
+   do {
       va_start(args,Description);
-      if (_error->Insert(GlobalError::ERROR, Description, args, msgSize) == false)
-        break;
+      retry = _error->Insert(GlobalError::ERROR, Description, args, msgSize);
       va_end(args);
-   }
+   } while (retry);
    return false;
 }
                                                                        /*}}}*/