In pipe_read_line Windows code, loop to ensure we get a whole line

from the child process; fixes observed problems when the returned
version number is '8.0.0' rather than '8.0.0rc1'.  Magnus Hagander

diff --git a/src/port/exec.c b/src/port/exec.c
index 19ab92a07253c641756858e1ec303bb1f879b8ce..62a833cb8520669a74b5a96b51e47491c1d6a870 100644 (file)
--- a/src/port/exec.c
+++ b/src/port/exec.c
@@ -9,7 +9,7 @@
  *
  *
  * IDENTIFICATION
- *   $PostgreSQL: pgsql/src/port/exec.c,v 1.33 2004/11/27 22:44:15 petere Exp $
+ *   $PostgreSQL: pgsql/src/port/exec.c,v 1.34 2004/12/20 17:40:59 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -486,30 +486,45 @@ pipe_read_line(char *cmd, char *line, int maxsize)
                      &si,
                      &pi))
    {
-       DWORD       bytesread = 0;
-
        /* Successfully started the process */
+       char   *lineptr;
 
        ZeroMemory(line, maxsize);
 
-       /* Let's see if we can read */
-       if (WaitForSingleObject(childstdoutrddup, 10000) != WAIT_OBJECT_0)
+       /* Try to read at least one line from the pipe */
+       /* This may require more than one wait/read attempt */
+       for (lineptr = line; lineptr < line+maxsize-1; )
        {
-           /* Got timeout */
-           CloseHandle(pi.hProcess);
-           CloseHandle(pi.hThread);
-           CloseHandle(childstdoutwr);
-           CloseHandle(childstdoutrddup);
-           return NULL;
+           DWORD       bytesread = 0;
+
+           /* Let's see if we can read */
+           if (WaitForSingleObject(childstdoutrddup, 10000) != WAIT_OBJECT_0)
+               break;      /* Timeout, but perhaps we got a line already */
+
+           if (!ReadFile(childstdoutrddup, lineptr, maxsize-(lineptr-line),
+                         &bytesread, NULL))
+               break;      /* Error, but perhaps we got a line already */
+
+           lineptr += strlen(lineptr);
+
+           if (!bytesread)
+               break; /* EOF */
+
+           if (strchr(line, '\n'))
+               break; /* One or more lines read */
        }
 
-       /* We try just once */
-       if (ReadFile(childstdoutrddup, line, maxsize, &bytesread, NULL) &&
-           bytesread > 0)
+       if (lineptr != line)
        {
-           /* So we read some data */
-           int         len = strlen(line);
-           retval = line;
+           /* OK, we read some data */
+           int         len;
+
+           /* If we got more than one line, cut off after the first \n */
+           lineptr = strchr(line,'\n');
+           if (lineptr)
+               *(lineptr+1) = '\0';
+
+           len = strlen(line);
 
            /*
             * If EOL is \r\n, convert to just \n. Because stdout is a
@@ -531,6 +546,8 @@ pipe_read_line(char *cmd, char *line, int maxsize)
             */
            if (len == 0 || line[len - 1] != '\n')
                strcat(line, "\n");
+
+           retval = line;
        }
 
        CloseHandle(pi.hProcess);