mingw: add routine to pipe a file descriptor to/from a command

2 files changed, 129 insertions, 18 deletions

diff --git a/include/mingw.h b/include/mingw.h
index d6ed909b5..bf8cd0c4c 100644
--- a/include/mingw.h
+++ b/include/mingw.h
@@ -142,6 +142,7 @@ int mingw_rename(const char*, const char*);
 #define rename mingw_rename
 
 FILE *mingw_popen(const char *cmd, const char *mode);
+int mingw_popen_fd(const char *cmd, const char *mode, int fd0, pid_t *pid);
 int mingw_pclose(FILE *fd);
 #undef popen
 #undef pclose
diff --git a/win32/popen.c b/win32/popen.c
index a7b2c7ec9..93d51bb55 100644
--- a/win32/popen.c
+++ b/win32/popen.c
@@ -26,24 +26,10 @@ static int mingw_pipe(HANDLE *readwrite)
         return 0;
 }
 
-FILE *mingw_popen(const char *cmd, const char *mode)
+static pipe_data *find_pipe(void)
 {
         int i;
         pipe_data *p = NULL;
-        FILE *fptr = NULL;
-        STARTUPINFO siStartInfo;
-        int success;
-        int fd;
-        int len, count;
-        int ip, ic;
-        char *cmd_buff = NULL;
-        const char *s;
-        char *t;
-
-        if ( cmd == NULL || *cmd == '\0' || mode == NULL ||
-                        (*mode != 'r' && *mode != 'w') ) {
-                return NULL;
-        }
 
         /* find an unused pipe structure */
         for ( i=0; i<num_pipes; ++i ) {
@@ -67,6 +53,35 @@ FILE *mingw_popen(const char *cmd, const char *mode)
                 num_pipes += 10;
         }
 
+        p->pipe[0] = INVALID_HANDLE_VALUE;
+        p->pipe[1] = INVALID_HANDLE_VALUE;
+
+        return p;
+}
+
+FILE *mingw_popen(const char *cmd, const char *mode)
+{
+        pipe_data *p;
+        FILE *fptr = NULL;
+        STARTUPINFO siStartInfo;
+        int success;
+        int fd;
+        int len, count;
+        int ip, ic;
+        char *cmd_buff = NULL;
+        const char *s;
+        char *t;
+
+        if ( cmd == NULL || *cmd == '\0' || mode == NULL ||
+                        (*mode != 'r' && *mode != 'w') ) {
+                return NULL;
+        }
+
+        /* find an unused pipe structure */
+        if ( (p=find_pipe()) == NULL ) {
+                return NULL;
+        }
+
         /* count double quotes */
         count = 0;
         for ( s=cmd; *s; ++s ) {
@@ -91,9 +106,6 @@ FILE *mingw_popen(const char *cmd, const char *mode)
         *t++ = '"';
         *t = '\0';
 
-        p->pipe[0] = INVALID_HANDLE_VALUE;
-        p->pipe[1] = INVALID_HANDLE_VALUE;
-
         /* Create the pipe */
         if ( mingw_pipe(p->pipe) == -1 ) {
                 goto finito;
@@ -168,6 +180,104 @@ finito:
         return fptr;
 }
 
+/*
+ * Open a pipe to a command where the file descriptor fd0 is used
+ * as input to the command (read mode) or as the destination of the
+ * output from the command (write mode).  The pid of the command is
+ * returned in the variable pid, which can be NULL.
+ */
+int mingw_popen_fd(const char *cmd, const char *mode, int fd0, pid_t *pid)
+{
+        pipe_data *p;
+        STARTUPINFO siStartInfo;
+        int success;
+        int fd = -1;
+        int ip, ic;
+
+        if ( cmd == NULL || *cmd == '\0' || mode == NULL ||
+                        (*mode != 'r' && *mode != 'w') ) {
+                return -1;
+        }
+
+        /* find an unused pipe structure */
+        if ( (p=find_pipe()) == NULL ) {
+                return -1;
+        }
+
+        /* Create the pipe */
+        if ( mingw_pipe(p->pipe) == -1 ) {
+                goto finito;
+        }
+
+        /* index of parent end of pipe */
+        ip = !(*mode == 'r');
+        /* index of child end of pipe */
+        ic = (*mode == 'r');
+
+        /* Make the parent end of the pipe non-inheritable */
+        SetHandleInformation(p->pipe[ip], HANDLE_FLAG_INHERIT, 0);
+
+        /* Now create the child process */
+        ZeroMemory(&siStartInfo, sizeof(STARTUPINFO));
+        siStartInfo.cb = sizeof(STARTUPINFO);
+        if ( *mode == 'r' ) {
+                siStartInfo.hStdInput = (HANDLE)_get_osfhandle(fd0);
+                siStartInfo.hStdOutput = p->pipe[ic];
+        }
+        else {
+                siStartInfo.hStdInput = p->pipe[ic];
+                siStartInfo.hStdOutput = (HANDLE)_get_osfhandle(fd0);
+        }
+        siStartInfo.hStdError = GetStdHandle(STD_ERROR_HANDLE);
+        siStartInfo.wShowWindow = SW_HIDE;
+        siStartInfo.dwFlags = STARTF_USESTDHANDLES|STARTF_USESHOWWINDOW;
+
+        success = CreateProcess(NULL,
+                                (LPTSTR)cmd,       /* command line */
+                                NULL,              /* process security attributes */
+                                NULL,              /* primary thread security attributes */
+                                TRUE,              /* handles are inherited */
+                                0,                 /* creation flags */
+                                NULL,              /* use parent's environment */
+                                NULL,              /* use parent's current directory */
+                                &siStartInfo,      /* STARTUPINFO pointer */
+                                &p->piProcInfo);   /* receives PROCESS_INFORMATION */
+
+        if ( !success ) {
+                goto finito;
+        }
+
+        /* close child end of pipe */
+        CloseHandle(p->pipe[ic]);
+        p->pipe[ic] = INVALID_HANDLE_VALUE;
+
+        if ( *mode == 'r' ) {
+                fd = _open_osfhandle((long)p->pipe[ip], _O_RDONLY|_O_BINARY);
+        }
+        else {
+                fd = _open_osfhandle((long)p->pipe[ip], _O_WRONLY|_O_BINARY);
+        }
+
+finito:
+        if ( fd == -1 ) {
+                if ( p->pipe[0] != INVALID_HANDLE_VALUE ) {
+                        CloseHandle(p->pipe[0]);
+                }
+                if ( p->pipe[1] != INVALID_HANDLE_VALUE ) {
+                        CloseHandle(p->pipe[1]);
+                }
+        }
+        else {
+                p->mode = *mode;
+                p->fd = fd;
+                if ( pid ) {
+                        *pid = (pid_t)p->piProcInfo.dwProcessId;
+                }
+        }
+
+        return fd;
+}
+
 int mingw_pclose(FILE *fp)
 {
         int i, ip, fd;