mingw: use real pid

The Windows port have so far been using process handles in place
of PID. However, this is not work consistent with what getpid
returns.

PIDs are system-global identifiers, but process handles are local
to a process. Using PIDs instead of process handles allows, for
instance, a user to kill a hung process with the Task Manager,
something that would have been impossible with process handles.

Change the code to use the real PID, and use OpenProcess to get a
process-handle. Store the PID and the process handle in a linked
list protected by a critical section, so we can safely close the
process handle later.

Linked list code written by Pat Thoyts.

Signed-off-by: Erik Faye-Lund <kusmabite@gmail.com>
Signed-off-by: Pat Thoyts <patthoyts@users.sourceforge.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/compat/mingw.c b/compat/mingw.c
index 701a555f13033e65cd56af33e666ca088b95dc11..736d03fa0c3b61163325d9ef6933111e4ef2e656 100644 (file)
--- a/compat/mingw.c
+++ b/compat/mingw.c
@@ -702,6 +702,14 @@ static int env_compare(const void *a, const void *b)
        return strcasecmp(*ea, *eb);
 }
 
+struct pinfo_t {
+       struct pinfo_t *next;
+       pid_t pid;
+       HANDLE proc;
+} pinfo_t;
+struct pinfo_t *pinfo = NULL;
+CRITICAL_SECTION pinfo_cs;
+
 static pid_t mingw_spawnve_fd(const char *cmd, const char **argv, char **env,
                              const char *dir,
                              int prepend_cmd, int fhin, int fhout, int fherr)
@@ -794,7 +802,26 @@ static pid_t mingw_spawnve_fd(const char *cmd, const char **argv, char **env,
                return -1;
        }
        CloseHandle(pi.hThread);
-       return (pid_t)pi.hProcess;
+
+       /*
+        * The process ID is the human-readable identifier of the process
+        * that we want to present in log and error messages. The handle
+        * is not useful for this purpose. But we cannot close it, either,
+        * because it is not possible to turn a process ID into a process
+        * handle after the process terminated.
+        * Keep the handle in a list for waitpid.
+        */
+       EnterCriticalSection(&pinfo_cs);
+       {
+               struct pinfo_t *info = xmalloc(sizeof(struct pinfo_t));
+               info->pid = pi.dwProcessId;
+               info->proc = pi.hProcess;
+               info->next = pinfo;
+               pinfo = info;
+       }
+       LeaveCriticalSection(&pinfo_cs);
+
+       return (pid_t)pi.dwProcessId;
 }
 
 static pid_t mingw_spawnve(const char *cmd, const char **argv, char **env,
@@ -1518,6 +1545,50 @@ char *getpass(const char *prompt)
        return strbuf_detach(&buf, NULL);
 }
 
+pid_t waitpid(pid_t pid, int *status, unsigned options)
+{
+       HANDLE h = OpenProcess(SYNCHRONIZE | PROCESS_QUERY_INFORMATION,
+           FALSE, pid);
+       if (!h) {
+               errno = ECHILD;
+               return -1;
+       }
+
+       if (options == 0) {
+               struct pinfo_t **ppinfo;
+               if (WaitForSingleObject(h, INFINITE) != WAIT_OBJECT_0) {
+                       CloseHandle(h);
+                       return 0;
+               }
+
+               if (status)
+                       GetExitCodeProcess(h, (LPDWORD)status);
+
+               EnterCriticalSection(&pinfo_cs);
+
+               ppinfo = &pinfo;
+               while (*ppinfo) {
+                       struct pinfo_t *info = *ppinfo;
+                       if (info->pid == pid) {
+                               CloseHandle(info->proc);
+                               *ppinfo = info->next;
+                               free(info);
+                               break;
+                       }
+                       ppinfo = &info->next;
+               }
+
+               LeaveCriticalSection(&pinfo_cs);
+
+               CloseHandle(h);
+               return pid;
+       }
+       CloseHandle(h);
+
+       errno = EINVAL;
+       return -1;
+}
+
 #ifndef NO_MINGW_REPLACE_READDIR
 /* MinGW readdir implementation to avoid extra lstats for Git */
 struct mingw_DIR

diff --git a/compat/mingw.h b/compat/mingw.h
index a5bde82b9a7b2ad5bb1743aa471cdef19148a8f5..7c4eeea38cd52bc6b719758f6346c0b9dcb96220 100644 (file)
--- a/compat/mingw.h
+++ b/compat/mingw.h
@@ -140,13 +140,7 @@ static inline int mingw_unlink(const char *pathname)
 }
 #define unlink mingw_unlink
 
-static inline pid_t waitpid(pid_t pid, int *status, unsigned options)
-{
-       if (options == 0)
-               return _cwait(status, pid, 0);
-       errno = EINVAL;
-       return -1;
-}
+pid_t waitpid(pid_t pid, int *status, unsigned options);
 
 #ifndef NO_OPENSSL
 #include <openssl/ssl.h>
@@ -321,11 +315,13 @@ void free_environ(char **env);
 static int mingw_main(); \
 int main(int argc, const char **argv) \
 { \
+       extern CRITICAL_SECTION pinfo_cs; \
        _fmode = _O_BINARY; \
        _setmode(_fileno(stdin), _O_BINARY); \
        _setmode(_fileno(stdout), _O_BINARY); \
        _setmode(_fileno(stderr), _O_BINARY); \
        argv[0] = xstrdup(_pgmptr); \
+       InitializeCriticalSection(&pinfo_cs); \
        return mingw_main(argc, argv); \
 } \
 static int mingw_main(c,v)