Give PTYs a sensible size

Fixes: ticket:1298, Gentoo#484298

3 files changed, 61 insertions, 7 deletions

diff --git a/paludis/util/process.cc b/paludis/util/process.cc
index 7b4356f97..ef00b003a 100644
--- a/paludis/util/process.cc
+++ b/paludis/util/process.cc
@@ -46,6 +46,7 @@
 #include <sys/types.h>
 #include <sys/wait.h>
 #include <sys/select.h>
+#include <sys/ioctl.h>
 
 using namespace paludis;
 
@@ -561,6 +562,9 @@ Process::run()
     if (_imp->echo_command_to)
         _imp->command.echo_command_to(*_imp->echo_command_to);
 
+    bool set_tty_size_envvars(false);
+    unsigned short columns(80), lines(24);
+
     std::unique_ptr<RunningProcessThread> thread;
     if (_imp->need_thread)
     {
@@ -589,11 +593,39 @@ Process::run()
 
         thread->extra_newlines_if_any_output_exists = _imp->extra_newlines_if_any_output_exists;
 
+        if ((_imp->capture_stdout || _imp->capture_stderr) && _imp->use_ptys)
+        {
+            int tty(::open("/dev/tty", O_RDONLY | O_CLOEXEC));
+            if (-1 == tty)
+                Log::get_instance()->message("util.system.gwinsz.open_failed", ll_debug, lc_context)
+                    << "open(/dev/tty) failed: " + std::string(std::strerror(errno));
+            else
+            {
+                struct winsize ws;
+                if (-1 == ::ioctl(tty, TIOCGWINSZ, &ws))
+                    Log::get_instance()->message("util.system.gwinsz.ioctl_failed", ll_warning, lc_context)
+                        << "ioctl(TIOCGWINSZ) failed: " + std::string(std::strerror(errno));
+                else if (0 == ws.ws_col || 0 == ws.ws_row)
+                    Log::get_instance()->message("util.system.gwinsz.dodgy", ll_warning, lc_context)
+                        << "Got zero for terminal columns and/or lines (" << ws.ws_col << "x" << ws.ws_row << "), ignoring";
+                else
+                {
+                    columns = ws.ws_col;
+                    lines = ws.ws_row;
+                }
+                if (-1 == ::close(tty))
+                    throw InternalError(PALUDIS_HERE, "close(/dev/tty) failed: " + std::string(std::strerror(errno)));
+            }
+            Log::get_instance()->message("util.system.gwinsz", ll_debug, lc_context)
+                << "Terminal size is " << columns << "x" << lines;
+            set_tty_size_envvars = true;
+        }
+
         if (_imp->capture_stdout)
         {
             thread->capture_stdout = _imp->capture_stdout;
             if (_imp->use_ptys)
-                thread->capture_stdout_pipe.reset(new Pty(true));
+                thread->capture_stdout_pipe.reset(new Pty(true, columns, lines));
             else
                 thread->capture_stdout_pipe.reset(new Pipe(true));
         }
@@ -602,7 +634,7 @@ Process::run()
         {
             thread->capture_stderr = _imp->capture_stderr;
             if (_imp->use_ptys)
-                thread->capture_stderr_pipe.reset(new Pty(true));
+                thread->capture_stderr_pipe.reset(new Pty(true, columns, lines));
             else
                 thread->capture_stderr_pipe.reset(new Pipe(true));
         }
@@ -749,6 +781,12 @@ Process::run()
                     throw ProcessError("dup2() failed");
             }
 
+            if (set_tty_size_envvars)
+            {
+                ::setenv("COLUMNS", stringify(columns).c_str(), 1);
+                ::setenv("LINES", stringify(lines).c_str(), 1);
+            }
+
             for (auto m(_imp->setenvs.begin()), m_end(_imp->setenvs.end()) ;
                     m != m_end ; ++m)
                 ::setenv(m->first.c_str(), m->second.c_str(), 1);
diff --git a/paludis/util/pty.cc b/paludis/util/pty.cc
index d2cbd4179..68c2c2e8c 100644
--- a/paludis/util/pty.cc
+++ b/paludis/util/pty.cc
@@ -26,6 +26,7 @@
 #include <errno.h>
 #include <cstring>
 #include <unistd.h>
+#include <sys/ioctl.h>
 #include "config.h"
 
 #ifdef HAVE_PTSNAME_R
@@ -41,16 +42,16 @@ PtyError::PtyError(const std::string & our_message) throw () :
 
 Pty::Pty()
 {
-    _init(false);
+    _init(false, 0, 0);
 }
 
-Pty::Pty(const bool close_exec)
+Pty::Pty(const bool close_exec, const unsigned short columns, const unsigned short lines)
 {
-    _init(close_exec);
+    _init(close_exec, columns, lines);
 }
 
 void
-Pty::_init(const bool close_exec)
+Pty::_init(const bool close_exec, const unsigned short columns, const unsigned short lines)
 {
     Context context("When creating pty FDs:");
 
@@ -100,6 +101,20 @@ Pty::_init(const bool close_exec)
 
     Log::get_instance()->message("util.pty.fds", ll_debug, lc_context) << "Pty FDs are '" << read_fd() << "', '"
         << write_fd() << "'";
+
+    if (0 != columns && 0 != lines)
+    {
+        struct winsize ws;
+        ws.ws_row = lines;
+        ws.ws_col = columns;
+        ws.ws_xpixel = ws.ws_ypixel = 0;
+        if (-1 == ioctl(_fds[1], TIOCSWINSZ, &ws))
+            Log::get_instance()->message("util.pty.swinsz.failed", ll_warning, lc_context)
+                << "ioctl(TIOCSWINSZ, { .ws_row = " << lines << ", .ws_col = " << columns << " }) failed: " + std::string(std::strerror(errno));
+        else
+            Log::get_instance()->message("util.pty.swinsz", ll_debug, lc_context)
+                << "Set Pty size to " << columns << "x" << lines;
+    }
 }
 
 Pty::~Pty()
diff --git a/paludis/util/pty.hh b/paludis/util/pty.hh
index 94406fe3f..58d74859f 100644
--- a/paludis/util/pty.hh
+++ b/paludis/util/pty.hh
@@ -65,7 +65,7 @@ namespace paludis
         public Channel
     {
         private:
-            void _init(const bool);
+            void _init(const bool, const unsigned short columns, const unsigned short lines);
 
         public:
             ///\name Basic operations
@@ -73,6 +73,7 @@ namespace paludis
 
             Pty();
             explicit Pty(const bool close_exec);
+            explicit Pty(const bool close_exec, const unsigned short columns, const unsigned short lines);
 
             virtual ~Pty();