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From: Corinna Vinschen <corinna@sourceware.org> To: cygwin-cvs@sourceware.org Subject: [newlib-cygwin] Cygwin: pipe: Use NtQuerySystemInformation() instead of EnumProcesses(). Date: Tue, 19 Oct 2021 11:06:58 +0000 (GMT) [thread overview] Message-ID: <20211019110658.763DA3858D39@sourceware.org> (raw) https://sourceware.org/git/gitweb.cgi?p=newlib-cygwin.git;h=745b547ebd03ce29fdbf223dd400e7f65aba1c7f commit 745b547ebd03ce29fdbf223dd400e7f65aba1c7f Author: Takashi Yano <takashi.yano@nifty.ne.jp> Date: Tue Oct 19 17:40:19 2021 +0900 Cygwin: pipe: Use NtQuerySystemInformation() instead of EnumProcesses(). - Using EnumProcess() breaks Windows Vista compatibility. This patch replaces EnumProcesses() with NtQuerySystemInformation(). Addresses: https://cygwin.com/pipermail/cygwin-developers/2021-October/012422.html Diff: --- winsup/cygwin/fhandler_pipe.cc | 50 ++++++++++++++++++++++++++++-------------- 1 file changed, 34 insertions(+), 16 deletions(-) diff --git a/winsup/cygwin/fhandler_pipe.cc b/winsup/cygwin/fhandler_pipe.cc index dd8b4f317..63e432160 100644 --- a/winsup/cygwin/fhandler_pipe.cc +++ b/winsup/cygwin/fhandler_pipe.cc @@ -20,7 +20,6 @@ details. */ #include "pinfo.h" #include "shared_info.h" #include "tls_pbuf.h" -#include <psapi.h> /* This is only to be used for writing. When reading, STATUS_PIPE_EMPTY simply means there's no data to be read. */ @@ -1190,27 +1189,47 @@ HANDLE fhandler_pipe::get_query_hdl_per_process (WCHAR *name, OBJECT_NAME_INFORMATION *ntfn) { + NTSTATUS status; ULONG len; - BOOL res; DWORD n_process = 256; - DWORD *proc_pids; + PSYSTEM_PROCESS_INFORMATION spi; do { /* Enumerate processes */ - DWORD nbytes = n_process * sizeof (DWORD); - proc_pids = (DWORD *) HeapAlloc (GetProcessHeap (), 0, nbytes); - if (!proc_pids) + DWORD nbytes = n_process * sizeof (SYSTEM_PROCESS_INFORMATION); + spi = (PSYSTEM_PROCESS_INFORMATION) HeapAlloc (GetProcessHeap (), + 0, nbytes); + if (!spi) return NULL; - res = EnumProcesses (proc_pids, nbytes, &len); - if (res && len < nbytes) + status = NtQuerySystemInformation (SystemProcessInformation, + spi, nbytes, &len); + if (NT_SUCCESS (status)) break; - res = FALSE; - HeapFree (GetProcessHeap (), 0, proc_pids); + HeapFree (GetProcessHeap (), 0, spi); n_process *= 2; } - while (n_process < (1L<<20)); - if (!res) + while (n_process < (1L<<20) && status == STATUS_INFO_LENGTH_MISMATCH); + if (!NT_SUCCESS (status)) return NULL; - n_process = len / sizeof (DWORD); + + /* In most cases, it is faster to check the processes in reverse order. + To do this, store PIDs into an array. */ + DWORD *proc_pids = (DWORD *) HeapAlloc (GetProcessHeap (), 0, + n_process * sizeof (DWORD)); + if (!proc_pids) + { + HeapFree (GetProcessHeap (), 0, spi); + return NULL; + } + PSYSTEM_PROCESS_INFORMATION p = spi; + n_process = 0; + while (true) + { + proc_pids[n_process++] = (DWORD)(intptr_t) p->UniqueProcessId; + if (!p->NextEntryOffset) + break; + p = (PSYSTEM_PROCESS_INFORMATION) ((char *) p + p->NextEntryOffset); + } + HeapFree (GetProcessHeap (), 0, spi); for (LONG i = (LONG) n_process - 1; i >= 0; i--) { @@ -1221,7 +1240,6 @@ fhandler_pipe::get_query_hdl_per_process (WCHAR *name, continue; /* Retrieve process handles */ - NTSTATUS status; DWORD n_handle = 256; PPROCESS_HANDLE_SNAPSHOT_INFORMATION phi; do @@ -1255,8 +1273,8 @@ fhandler_pipe::get_query_hdl_per_process (WCHAR *name, /* Retrieve handle */ HANDLE h = (HANDLE)(intptr_t) phi->Handles[j].HandleValue; - res = DuplicateHandle (proc, h, GetCurrentProcess (), &h, - FILE_READ_DATA, 0, 0); + BOOL res = DuplicateHandle (proc, h, GetCurrentProcess (), &h, + FILE_READ_DATA, 0, 0); if (!res) continue;
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