/// <summary>
/// Retrieves the number of open file descriptors for the specified pid
/// </summary>
/// <returns>A count of file descriptors for this process.</returns>
/// <remarks>
/// This function doesn't use the helper since it seems to allow passing NULL
/// values in to the buffer and length parameters to get back an estimation
/// of how much data we will need to allocate; the other flavors don't seem
/// to support doing that.
/// </remarks>
internal static unsafe int GetFileDescriptorCountForPid(int pid)
{
// Negative PIDs are invalid
if (pid < 0)
{
throw new ArgumentOutOfRangeException("pid");
}
// Query for an estimation about the size of the buffer we will need. This seems
// to add some padding from the real number, so we don't need to do that
int result = proc_pidinfo(pid, PROC_PIDLISTFDS, 0, (proc_fdinfo *)null, 0);
if (result <= 0)
{
// If we were unable to access the information, just return the empty list.
// This is likely to happen for privileged processes, if the process went away
// by the time we tried to query it, etc.
return(0);
}
proc_fdinfo[] fds;
int size = (int)(result / Marshal.SizeOf <proc_fdinfo>()) + 1;
// Just in case the app opened a ton of handles between when we asked and now,
// make sure we retry if our buffer is filled
do
{
fds = new proc_fdinfo[size];
fixed(proc_fdinfo *pFds = fds)
{
result = proc_pidinfo(pid, PROC_PIDLISTFDS, 0, pFds, Marshal.SizeOf <proc_fdinfo>() * fds.Length);
}
if (result <= 0)
{
// If we were unable to access the information, just return the empty list.
// This is likely to happen for privileged processes, if the process went away
// by the time we tried to query it, etc.
return(0);
}
else
{
checked
{
size *= 2;
}
}
}while (result == (fds.Length * Marshal.SizeOf <proc_fdinfo>()));
Debug.Assert((result % Marshal.SizeOf <proc_fdinfo>()) == 0);
return((int)(result / Marshal.SizeOf <proc_fdinfo>()));
}
/// <summary>
/// Retrieves the number of open file descriptors for the specified pid
/// </summary>
/// <returns>A count of file descriptors for this process.</returns>
/// <remarks>
/// This function doesn't use the helper since it seems to allow passing NULL
/// values in to the buffer and length parameters to get back an estimation
/// of how much data we will need to allocate; the other flavors don't seem
/// to support doing that.
/// </remarks>
internal static unsafe int GetFileDescriptorCountForPid(int pid)
{
// Negative PIDs are invalid
if (pid < 0)
{
throw new ArgumentOutOfRangeException("pid");
}
// Query for an estimation about the size of the buffer we will need. This seems
// to add some padding from the real number, so we don't need to do that
int result = proc_pidinfo(pid, PROC_PIDLISTFDS, 0, (proc_fdinfo*)null, 0);
if (result <= 0)
{
// If we were unable to access the information, just return the empty list.
// This is likely to happen for privileged processes, if the process went away
// by the time we tried to query it, etc.
return 0;
}
proc_fdinfo[] fds;
int size = (int)(result / Marshal.SizeOf<proc_fdinfo>()) + 1;
// Just in case the app opened a ton of handles between when we asked and now,
// make sure we retry if our buffer is filled
do
{
fds = new proc_fdinfo[size];
fixed (proc_fdinfo* pFds = fds)
{
result = proc_pidinfo(pid, PROC_PIDLISTFDS, 0, pFds, Marshal.SizeOf<proc_fdinfo>() * fds.Length);
}
if (result <= 0)
{
// If we were unable to access the information, just return the empty list.
// This is likely to happen for privileged processes, if the process went away
// by the time we tried to query it, etc.
return 0;
}
else
{
checked
{
size *= 2;
}
}
}
while (result == (fds.Length * Marshal.SizeOf<proc_fdinfo>()));
Debug.Assert((result % Marshal.SizeOf<proc_fdinfo>()) == 0);
return (int)(result / Marshal.SizeOf<proc_fdinfo>());
}
private static unsafe extern int proc_pidinfo(
int pid,
int flavor,
ulong arg,
proc_fdinfo* buffer,
int bufferSize);
