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@xxxxxxxxx>
Signed-off-by: Pat Thoyts <patthoyts@xxxxxxxxxxxxxxxxxxxxx>
---
compat/mingw.c | 73 +++++++++++++++++++++++++++++++++++++++++++++++++++++++-
compat/mingw.h | 10 ++-----
2 files changed, 75 insertions(+), 8 deletions(-)
diff --git a/compat/mingw.c b/compat/mingw.c
index 701a555..736d03f 100644
--- 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 a5bde82..7c4eeea 100644
--- 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)
--
1.7.3.2.162.g09d37
--
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