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authorKaren Arutyunov <karen@codesynthesis.com>2017-04-24 13:51:56 +0300
committerKaren Arutyunov <karen@codesynthesis.com>2017-04-24 14:49:11 +0300
commitb8526f8f0cb24c457da8c88877e516943e3e1902 (patch)
treef63a266ab7710a21c3d1cbca132194b1c7ad5b5f /butl
parenteb4810893eb4c8379c3455f1e8a75ccd3b911aa6 (diff)
Make fdnull() to return auto_fd
Diffstat (limited to 'butl')
-rw-r--r--butl/curl.cxx8
-rw-r--r--butl/fdstream17
-rw-r--r--butl/fdstream.cxx55
-rw-r--r--butl/process.cxx46
4 files changed, 81 insertions, 45 deletions
diff --git a/butl/curl.cxx b/butl/curl.cxx
index 4951b52..12a1d54 100644
--- a/butl/curl.cxx
+++ b/butl/curl.cxx
@@ -25,7 +25,7 @@ namespace butl
case ftp_get:
case http_get:
{
- d.pipe.in.reset (fdnull ()); // /dev/null
+ d.pipe.in = fdnull (); // /dev/null
return d.pipe.in.get ();
}
}
@@ -60,7 +60,7 @@ namespace butl
out.open (move (d.pipe.out));
}
else
- d.pipe.in.reset (fdnull ()); // /dev/null
+ d.pipe.in = fdnull (); // /dev/null
return d.pipe.in.get ();
}
@@ -85,7 +85,7 @@ namespace butl
case ftp_put:
case http_post: // May or may not produce output.
{
- d.pipe.out.reset (fdnull ());
+ d.pipe.out = fdnull ();
return d.pipe.out.get (); // /dev/null
}
}
@@ -113,7 +113,7 @@ namespace butl
{
d.options.push_back ("-o");
d.options.push_back (f.string ().c_str ());
- d.pipe.out.reset (fdnull ()); // /dev/null
+ d.pipe.out = fdnull (); // /dev/null
}
return d.pipe.out.get ();
diff --git a/butl/fdstream b/butl/fdstream
index afc3ef6..df39808 100644
--- a/butl/fdstream
+++ b/butl/fdstream
@@ -575,9 +575,8 @@ namespace butl
// Open the null device (e.g., /dev/null) that discards all data written to
// it and provides no data for read operations (i.e., yelds EOF on read).
- // Return file descriptor on success, set errno and return -1 otherwise.
- // Note that it's the caller's responsibility to close the returned file
- // descriptor.
+ // Return an auto_fd that holds its file descriptor on success and throwing
+ // ios::failure otherwise.
//
// On Windows the null device is NUL and writing anything substantial to it
// (like redirecting a process' output) is extremely slow, as in, an order
@@ -593,18 +592,14 @@ namespace butl
// and read from the descriptor.
//
// Note that on POSIX the FD_CLOEXEC flag is set for the file descriptor to
- // prevent its leakage into child processes.
- //
- // @@ You may have noticed that this interface doesn't match fdopen() (it
- // does not throw and return int instead of auto_fd). The reason for this
- // is process and its need to translate everything to process_error).
- // Once we solve that we can clean this up as well.
+ // prevent its leakage into child processes. On Windows, for the same
+ // purpose, the _O_NOINHERIT flag is set.
//
#ifndef _WIN32
- LIBBUTL_EXPORT int
+ LIBBUTL_EXPORT auto_fd
fdnull () noexcept;
#else
- LIBBUTL_EXPORT int
+ LIBBUTL_EXPORT auto_fd
fdnull (bool temp = false) noexcept;
#endif
diff --git a/butl/fdstream.cxx b/butl/fdstream.cxx
index 19ef6c5..68168f3 100644
--- a/butl/fdstream.cxx
+++ b/butl/fdstream.cxx
@@ -47,7 +47,7 @@ namespace butl
// throw_ios_failure
//
template <bool v>
- static inline typename enable_if<v>::type
+ [[noreturn]] static inline typename enable_if<v>::type
throw_ios_failure (error_code e, const char* m)
{
// The idea here is to make an error code to be saved into failure
@@ -65,7 +65,7 @@ namespace butl
}
template <bool v>
- static inline typename enable_if<!v>::type
+ [[noreturn]] static inline typename enable_if<!v>::type
throw_ios_failure (error_code e, const char* m)
{
throw ios_base::failure (m != nullptr ? m : e.message ().c_str ());
@@ -73,7 +73,7 @@ namespace butl
// Throw system_error with generic_category.
//
- static inline void
+ [[noreturn]] static inline void
throw_ios_failure (int errno_code, const char* m = nullptr)
{
error_code ec (errno_code, generic_category ());
@@ -810,10 +810,15 @@ namespace butl
return close (fd) == 0;
}
- int
+ auto_fd
fdnull () noexcept
{
- return open ("/dev/null", O_RDWR | O_CLOEXEC);
+ int fd (open ("/dev/null", O_RDWR | O_CLOEXEC));
+
+ if (fd == -1)
+ throw_ios_failure (errno);
+
+ return auto_fd (fd);
}
fdstream_mode
@@ -955,13 +960,20 @@ namespace butl
return _close (fd) == 0;
}
- int
+ auto_fd
fdnull (bool temp) noexcept
{
// No need to translate \r\n before sending it to void.
//
if (!temp)
- return _sopen ("nul", _O_RDWR | _O_BINARY | _O_NOINHERIT, _SH_DENYNO);
+ {
+ int fd (_sopen ("nul", _O_RDWR | _O_BINARY | _O_NOINHERIT, _SH_DENYNO));
+
+ if (fd == -1)
+ throw_ios_failure (errno);
+
+ return auto_fd (fd);
+ }
try
{
@@ -969,20 +981,24 @@ namespace butl
// the temporary file that avoid any allocations and exceptions.
//
path p (path::temp_path ("null")); // Can throw.
- return _sopen (p.string ().c_str (),
- (_O_CREAT |
- _O_RDWR |
- _O_BINARY | // Don't translate.
- _O_TEMPORARY | // Remove on close.
- _O_SHORT_LIVED | // Don't flush to disk.
- _O_NOINHERIT), // Don't inherit by child process.
- _SH_DENYNO,
- _S_IREAD | _S_IWRITE);
+ int fd (_sopen (p.string ().c_str (),
+ (_O_CREAT |
+ _O_RDWR |
+ _O_BINARY | // Don't translate.
+ _O_TEMPORARY | // Remove on close.
+ _O_SHORT_LIVED | // Don't flush to disk.
+ _O_NOINHERIT), // Don't inherit by child process.
+ _SH_DENYNO,
+ _S_IREAD | _S_IWRITE));
+
+ if (fd == -1)
+ throw_ios_failure (errno);
+
+ return auto_fd (fd);
}
catch (const bad_alloc&)
{
- errno = ENOMEM;
- return -1;
+ throw_ios_failure (ENOMEM);
}
catch (const system_error& e)
{
@@ -990,8 +1006,7 @@ namespace butl
//
assert (e.code ().category () == generic_category ());
- errno = e.code ().value ();
- return -1;
+ throw_ios_failure (e.code ().value ());
}
}
diff --git a/butl/process.cxx b/butl/process.cxx
index 850ba9b..c427aa8 100644
--- a/butl/process.cxx
+++ b/butl/process.cxx
@@ -286,13 +286,26 @@ namespace butl
}
};
- auto open_null = [&fail] () -> auto_fd
+ auto open_null = [] () -> auto_fd
{
- auto_fd fd (fdnull ());
- if (fd.get () == -1)
- fail (false);
+ try
+ {
+ return fdnull ();
+ }
+ catch (const ios_base::failure& e)
+ {
+ // Translate to process_error.
+ //
+ // For old versions of g++ (as of 4.9) ios_base::failure is not derived
+ // from system_error and so we cannot recover the errno value. Lets use
+ // EIO in this case. This is a temporary code after all.
+ //
+ const system_error* se (dynamic_cast<const system_error*> (&e));
- return fd;
+ throw process_error (se != nullptr
+ ? se->code ().value ()
+ : EIO);
+ }
};
// If we are asked to open null (-2) then open "half-pipe".
@@ -940,17 +953,30 @@ namespace butl
throw process_error (m == nullptr ? last_error_msg () : m);
};
- auto open_null = [&fail] () -> auto_fd
+ auto open_null = [] () -> auto_fd
{
// Note that we are using a faster, temporary file-based emulation of
// NUL since we have no way of making sure the child buffers things
// properly (and by default they seem no to).
//
- auto_fd fd (fdnull (true));
- if (fd.get () == -1)
- fail ();
+ try
+ {
+ return fdnull (true);
+ }
+ catch (const ios_base::failure& e)
+ {
+ // Translate to process_error.
+ //
+ // For old versions of g++ (as of 4.9) ios_base::failure is not derived
+ // from system_error and so we cannot recover the errno value. Lets use
+ // EIO in this case. This is a temporary code after all.
+ //
+ const system_error* se (dynamic_cast<const system_error*> (&e));
- return fd;
+ throw process_error (se != nullptr
+ ? se->code ().value ()
+ : EIO);
+ }
};
// If we are asked to open null (-2) then open "half-pipe".