From e3f8001e5c6621d9942fc3832306d1b85f57e503 Mon Sep 17 00:00:00 2001
From: Brad Anderson <brad@cloudant.com>
Date: Fri, 20 Aug 2010 11:05:21 -0400
Subject: a bit more cleanup of root dir

---
 .../c_src/spawnkillable/couchspawnkillable_win.c   | 145 +++++++++++++++++++++
 1 file changed, 145 insertions(+)
 create mode 100644 apps/couch/c_src/spawnkillable/couchspawnkillable_win.c

(limited to 'apps/couch')

diff --git a/apps/couch/c_src/spawnkillable/couchspawnkillable_win.c b/apps/couch/c_src/spawnkillable/couchspawnkillable_win.c
new file mode 100644
index 00000000..06782315
--- /dev/null
+++ b/apps/couch/c_src/spawnkillable/couchspawnkillable_win.c
@@ -0,0 +1,145 @@
+// Licensed under the Apache License, Version 2.0 (the "License"); you may not
+// use this file except in compliance with the License.  You may obtain a copy of
+// the License at
+//
+//   http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+// WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the
+// License for the specific language governing permissions and limitations under
+// the License.
+
+// Do what 2 lines of shell script in couchspawnkillable does...
+// * Create a new suspended process with the same (duplicated) standard 
+//   handles as us.
+// * Write a line to stdout, consisting of the path to ourselves, plus
+//   '--kill {pid}' where {pid} is the PID of the newly created process.
+// * Un-suspend the new process.
+// * Wait for the process to terminate.
+// * Terminate with the child's exit-code.
+
+// Later, couch will call us with --kill and the PID, so we dutifully
+// terminate the specified PID.
+
+#include <stdlib.h>
+#include "windows.h"
+
+char *get_child_cmdline(int argc, char **argv)
+{
+    // make a new command-line, but skipping me.
+    // XXX - todo - spaces etc in args???
+    int i;
+    char *p, *cmdline;
+    int nchars = 0;
+    int nthis = 1;
+    for (i=1;i<argc;i++)
+        nchars += strlen(argv[i])+1;
+    cmdline = p = malloc(nchars+1);
+    if (!cmdline)
+        return NULL;
+    for (i=1;i<argc;i++) {
+        nthis = strlen(argv[i]);
+        strncpy(p, argv[i], nthis);
+        p[nthis] = ' ';
+        p += nthis+1;
+    }
+    // Replace the last space we added above with a '\0'
+    cmdline[nchars-1] = '\0';
+    return cmdline;
+}
+
+// create the child process, returning 0, or the exit-code we will
+// terminate with.
+int create_child(int argc, char **argv, PROCESS_INFORMATION *pi)
+{
+    char buf[1024];
+    DWORD dwcreate;
+    STARTUPINFO si;
+    char *cmdline;
+    if (argc < 2)
+        return 1;
+    cmdline = get_child_cmdline(argc, argv);
+    if (!cmdline)
+        return 2;
+
+    memset(&si, 0, sizeof(si));
+    si.cb = sizeof(si);
+    // depending on how *our* parent is started, we may or may not have
+    // a valid stderr stream - so although we try and duplicate it, only
+    // failing to duplicate stdin and stdout are considered fatal.
+    if (!DuplicateHandle(GetCurrentProcess(),
+                       GetStdHandle(STD_INPUT_HANDLE),
+                       GetCurrentProcess(),
+                       &si.hStdInput,
+                       0,
+                       TRUE, // inheritable
+                       DUPLICATE_SAME_ACCESS) ||
+       !DuplicateHandle(GetCurrentProcess(),
+                       GetStdHandle(STD_OUTPUT_HANDLE),
+                       GetCurrentProcess(),
+                       &si.hStdOutput,
+                       0,
+                       TRUE, // inheritable
+                       DUPLICATE_SAME_ACCESS)) {
+        return 3;
+    }
+    DuplicateHandle(GetCurrentProcess(),
+                   GetStdHandle(STD_ERROR_HANDLE),
+                   GetCurrentProcess(),
+                   &si.hStdError,
+                   0,
+                   TRUE, // inheritable
+                   DUPLICATE_SAME_ACCESS);
+
+    si.dwFlags = STARTF_USESTDHANDLES;
+    dwcreate = CREATE_SUSPENDED;
+    if (!CreateProcess( NULL, cmdline,
+                        NULL,
+                        NULL,
+                        TRUE, // inherit handles
+                        dwcreate,
+                        NULL, // environ
+                        NULL, // cwd
+                        &si,
+                        pi))
+        return 4;
+    return 0;
+}
+
+// and here we go...
+int main(int argc, char **argv)
+{
+    char out_buf[1024];
+    int rc;
+    DWORD cbwritten;
+    DWORD exitcode;
+    PROCESS_INFORMATION pi;
+    if (argc==3 && strcmp(argv[1], "--kill")==0) {
+        HANDLE h = OpenProcess(PROCESS_TERMINATE, 0, atoi(argv[2]));
+        if (!h)
+            return 1;
+        if (!TerminateProcess(h, 0))
+            return 2;
+        CloseHandle(h);
+        return 0;
+    }
+    // spawn the new suspended process
+    rc = create_child(argc, argv, &pi);
+    if (rc)
+        return rc;
+    // Write the 'terminate' command, which includes this PID, back to couch.
+    // *sob* - what about spaces etc?
+    sprintf_s(out_buf, sizeof(out_buf), "%s --kill %d\n", 
+              argv[0], pi.dwProcessId);
+    WriteFile(GetStdHandle(STD_OUTPUT_HANDLE), out_buf, strlen(out_buf), 
+              &cbwritten, NULL);
+    // Let the child process go...
+    ResumeThread(pi.hThread);
+    // Wait for the process to terminate so we can reflect the exit code
+    // back to couch.
+    WaitForSingleObject(pi.hProcess, INFINITE);
+    if (!GetExitCodeProcess(pi.hProcess, &exitcode))
+        return 6;
+    return exitcode;
+}
-- 
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