reformat for readability; more prep. for patch 1376506

[wxWidgets.git] / src / unix / snglinst.cpp

diff --git a/src/unix/snglinst.cpp b/src/unix/snglinst.cpp
index 8b569946b165579cd9332fea966fc06ad57a2678..bdd773a19e470197655edd8c049304d09864463b 100644 (file)
--- a/src/unix/snglinst.cpp
+++ b/src/unix/snglinst.cpp
@@ -7,7 +7,7 @@
 // Created:     09.06.01
 // RCS-ID:      $Id$
 // Copyright:   (c) 2001 Vadim Zeitlin <zeitlin@dptmaths.ens-cachan.fr>
 // Created:     09.06.01
 // RCS-ID:      $Id$
 // Copyright:   (c) 2001 Vadim Zeitlin <zeitlin@dptmaths.ens-cachan.fr>

-// License:     wxWindows license
+// License:     wxWindows licence

 ///////////////////////////////////////////////////////////////////////////////
 
 // ============================================================================
 ///////////////////////////////////////////////////////////////////////////////
 
 // ============================================================================


@@ -18,10 +18,6 @@
 // headers
 // ----------------------------------------------------------------------------
 
 // headers
 // ----------------------------------------------------------------------------
 

-#ifdef __GNUG__
-    #pragma implementation "snglinst.h"
-#endif
-

 // For compilers that support precompilation, includes "wx.h".
 #include "wx/wxprec.h"
 
 // For compilers that support precompilation, includes "wx.h".
 #include "wx/wxprec.h"
 


@@ -35,17 +31,18 @@
     #include "wx/string.h"
     #include "wx/log.h"
     #include "wx/intl.h"
     #include "wx/string.h"
     #include "wx/log.h"
     #include "wx/intl.h"

-    #include "wx/file.h"

 #endif //WX_PRECOMP
 
 #endif //WX_PRECOMP
 

+#include "wx/file.h"

 #include "wx/utils.h"           // wxGetHomeDir()
 
 #include "wx/snglinst.h"
 
 #include <unistd.h>
 #include <sys/types.h>
 #include "wx/utils.h"           // wxGetHomeDir()
 
 #include "wx/snglinst.h"
 
 #include <unistd.h>
 #include <sys/types.h>

-#include <sys/stat.h>
+#include <sys/stat.h>           // for S_I[RW]USR

 #include <signal.h>             // for kill()
 #include <signal.h>             // for kill()

+#include <errno.h>

 
 #ifdef HAVE_FCNTL
     #include <fcntl.h>
 
 #ifdef HAVE_FCNTL
     #include <fcntl.h>


@@ -57,15 +54,28 @@
 #endif // fcntl()/flock()
 
 // ----------------------------------------------------------------------------
 #endif // fcntl()/flock()
 
 // ----------------------------------------------------------------------------

-// private functions: (exclusively) lock/unlock the file
+// constants

 // ----------------------------------------------------------------------------
 
 // ----------------------------------------------------------------------------
 

+// argument of wxLockFile()

 enum LockOperation
 {
     LOCK,
     UNLOCK
 };
 
 enum LockOperation
 {
     LOCK,
     UNLOCK
 };
 

+// return value of CreateLockFile()
+enum LockResult
+{
+    LOCK_ERROR = -1,
+    LOCK_EXISTS,
+    LOCK_CREATED
+};
+
+// ----------------------------------------------------------------------------
+// private functions: (exclusively) lock/unlock the file
+// ----------------------------------------------------------------------------
+

 #ifdef HAVE_FCNTL
 
 static int wxLockFile(int fd, LockOperation lock)
 #ifdef HAVE_FCNTL
 
 static int wxLockFile(int fd, LockOperation lock)


@@ -75,9 +85,9 @@ static int wxLockFile(int fd, LockOperation lock)
     fl.l_type = lock == LOCK ? F_WRLCK : F_UNLCK;
 
     // lock the entire file
     fl.l_type = lock == LOCK ? F_WRLCK : F_UNLCK;
 
     // lock the entire file

-    fl.l_whence =

     fl.l_start =
     fl.l_start =

-    fl.l_len = 0;
+    fl.l_len =
+    fl.l_whence = 0;

 
     // is this needed?
     fl.l_pid = getpid();
 
     // is this needed?
     fl.l_pid = getpid();


@@ -115,7 +125,7 @@ public:
 
 private:
     // try to create and lock the file
 
 private:
     // try to create and lock the file

-    bool CreateLockFile();
+    LockResult CreateLockFile();

 
     // unlock and remove the lock file
     void Unlock();
 
     // unlock and remove the lock file
     void Unlock();


@@ -134,12 +144,12 @@ private:
 // wxSingleInstanceCheckerImpl implementation
 // ============================================================================
 
 // wxSingleInstanceCheckerImpl implementation
 // ============================================================================
 

-bool wxSingleInstanceCheckerImpl::CreateLockFile()
+LockResult wxSingleInstanceCheckerImpl::CreateLockFile()

 {
     // try to open the file
 {
     // try to open the file

-    m_fdLock = open(m_nameLock,
+    m_fdLock = open(m_nameLock.fn_str(),

                     O_WRONLY | O_CREAT | O_EXCL,
                     O_WRONLY | O_CREAT | O_EXCL,

-                    S_IREAD | S_IWRITE);
+                    S_IRUSR | S_IWUSR);

 
     if ( m_fdLock != -1 )
     {
 
     if ( m_fdLock != -1 )
     {


@@ -152,7 +162,7 @@ bool wxSingleInstanceCheckerImpl::CreateLockFile()
 
             // use char here, not wxChar!
             char buf[256]; // enough for any PID size
 
             // use char here, not wxChar!
             char buf[256]; // enough for any PID size

-            int len = sprintf(buf, "%d", m_pidLocker) + 1;
+            int len = sprintf(buf, "%d", (int)m_pidLocker) + 1;

 
             if ( write(m_fdLock, buf, len) != len )
             {
 
             if ( write(m_fdLock, buf, len) != len )
             {


@@ -161,33 +171,86 @@ bool wxSingleInstanceCheckerImpl::CreateLockFile()
 
                 Unlock();
 
 
                 Unlock();
 

-                return FALSE;
+                return LOCK_ERROR;

             }
 
             fsync(m_fdLock);
 
             }
 
             fsync(m_fdLock);
 

-            return TRUE;
+            // change file's permission so that only this user can access it:
+            if ( chmod(m_nameLock.fn_str(), S_IRUSR | S_IWUSR) != 0 )
+            {
+                wxLogSysError(_("Failed to set permissions on lock file '%s'"),
+                              m_nameLock.c_str());
+
+                Unlock();
+                
+                return LOCK_ERROR;
+            }
+
+            return LOCK_CREATED;

         }
         }

+        else // failure: see what exactly happened
+        {
+            close(m_fdLock);
+            m_fdLock = -1;

 
 

-        // couldn't lock: this might have happened because of a race
-        // condition: maybe another instance opened and locked the file
-        // between our calls to open() and flock()
-        close(m_fdLock);
-        m_fdLock = -1;
+            if ( errno != EACCES && errno != EAGAIN )
+            {
+                wxLogSysError(_("Failed to lock the lock file '%s'"),
+                              m_nameLock.c_str());
+
+                unlink(m_nameLock.fn_str());
+
+                return LOCK_ERROR;
+            }
+            //else: couldn't lock because the lock is held by another process:
+            //      this might have happened because of a race condition:
+            //      maybe another instance opened and locked the file between
+            //      our calls to open() and flock(), so don't give an error
+        }

     }
 
     // we didn't create and lock the file
     }
 
     // we didn't create and lock the file

-    return FALSE;
+    return LOCK_EXISTS;

 }
 
 bool wxSingleInstanceCheckerImpl::Create(const wxString& name)
 {
     m_nameLock = name;
 
 }
 
 bool wxSingleInstanceCheckerImpl::Create(const wxString& name)
 {
     m_nameLock = name;
 

-    if ( CreateLockFile() )
+    switch ( CreateLockFile() )

     {
     {

-        // nothing more to do
-        return TRUE;
+        case LOCK_EXISTS:
+            // there is a lock file, check below if it is still valid
+            break;
+
+        case LOCK_CREATED:
+            // nothing more to do
+            return TRUE;
+
+        case LOCK_ERROR:
+            // oops...
+            return FALSE;
+    }
+
+    // Check if the file is owned by current user and has 0600 permissions.
+    // If it doesn't, it's a fake file, possibly meant as a DoS attack, and
+    // so we refuse to touch it:
+    wxStructStat stats;
+    if ( wxStat(name, &stats) != 0 )
+    {
+        wxLogSysError(_("Failed to inspect the lock file '%s'"), name.c_str());
+        return false;
+    }
+    if ( stats.st_uid != getuid() )
+    {
+        wxLogError(_("Lock file '%s' has incorrect owner."), name.c_str());
+        return false;
+    }
+    if ( stats.st_mode != (S_IFREG | S_IRUSR | S_IWUSR) )
+    {
+        wxLogError(_("Lock file '%s' has incorrect permissions."), name.c_str());
+        return false;

     }
 
     // try to open the file for reading and get the PID of the process
     }
 
     // try to open the file for reading and get the PID of the process


@@ -210,18 +273,18 @@ bool wxSingleInstanceCheckerImpl::Create(const wxString& name)
     }
 
     char buf[256];
     }
 
     char buf[256];

-    off_t count = file.Read(buf, WXSIZEOF(buf));
+    ssize_t count = file.Read(buf, WXSIZEOF(buf));

     if ( count == wxInvalidOffset )
     {
         wxLogError(_("Failed to read PID from lock file."));
     }
     else
     {
     if ( count == wxInvalidOffset )
     {
         wxLogError(_("Failed to read PID from lock file."));
     }
     else
     {

-        if ( sscanf(buf, "%d", &m_pidLocker) == 1 )
+        if ( sscanf(buf, "%d", (int *)&m_pidLocker) == 1 )

         {
             if ( kill(m_pidLocker, 0) != 0 )
             {
         {
             if ( kill(m_pidLocker, 0) != 0 )
             {

-                if ( unlink(name) != 0 )
+                if ( unlink(name.fn_str()) != 0 )

                 {
                     wxLogError(_("Failed to remove stale lock file '%s'."),
                                name.c_str());
                 {
                     wxLogError(_("Failed to remove stale lock file '%s'."),
                                name.c_str());


@@ -241,7 +304,7 @@ bool wxSingleInstanceCheckerImpl::Create(const wxString& name)
         }
         else
         {
         }
         else
         {

-            wxLogWarning(_("Invalid lock file '%s'."));
+            wxLogWarning(_("Invalid lock file '%s'."), name.c_str());

         }
     }
 
         }
     }
 


@@ -255,7 +318,7 @@ void wxSingleInstanceCheckerImpl::Unlock()
 {
     if ( m_fdLock != -1 )
     {
 {
     if ( m_fdLock != -1 )
     {

-        if ( unlink(m_nameLock) != 0 )
+        if ( unlink(m_nameLock.fn_str()) != 0 )

         {
             wxLogSysError(_("Failed to remove lock file '%s'"),
                           m_nameLock.c_str());
         {
             wxLogSysError(_("Failed to remove lock file '%s'"),
                           m_nameLock.c_str());


@@ -295,7 +358,12 @@ bool wxSingleInstanceChecker::Create(const wxString& name,
     wxString fullname = path;
     if ( fullname.empty() )
     {
     wxString fullname = path;
     if ( fullname.empty() )
     {

-        fullname << wxGetHomeDir() << _T('/');
+        fullname = wxGetHomeDir();
+    }
+
+    if ( fullname.Last() != _T('/') )
+    {
+        fullname += _T('/');

     }
 
     fullname << name;
     }
 
     fullname << name;