curl_formadd: fix file upload on VMS

For the standard VMS text file formats, VMS needs to read the file to
get the actual file size.

For the standard VMS binary file formats, VMS needs a special format of
fopen() call so that it stops reading at the logical end of file instead
of at the end of the blocks allocated to the file.

I structured the patch this way as I was not sure about changing the
structures or parameters to the routines, but would prefer to only call
the stat() function once and pass the information to where the fopen()
call is made.

Bug: https://sourceforge.net/p/curl/bugs/758/

lib/formdata.c

@@ -774,6 +774,70 @@ CURLFORMcode curl_formadd(struct curl_httppost **httppost,
   return result;
 }
 
+#ifdef __VMS
+#include <fabdef.h>
+/*
+ * get_vms_file_size does what it takes to get the real size of the file
+ *
+ * For fixed files, find out the size of the EOF block and adjust.
+ *
+ * For all others, have to read the entire file in, discarding the contents.
+ * Most posted text files will be small, and binary files like zlib archives
+ * and CD/DVD images should be either a STREAM_LF format or a fixed format.
+ *
+ */
+curl_off_t VmsRealFileSize(const char * name,
+                           const struct_stat * stat_buf)
+{
+  char buffer[8192];
+  curl_off_t count;
+  int ret_stat;
+  FILE * file;
+
+  file = fopen(name, "r");
+  if(file == NULL)
+    return 0;
+
+  count = 0;
+  ret_stat = 1;
+  while(ret_stat > 0) {
+    ret_stat = fread(buffer, 1, sizeof(buffer), file);
+    if(ret_stat != 0)
+      count += ret_stat;
+  }
+  fclose(file);
+
+  return count;
+}
+
+/*
+ *
+ *  VmsSpecialSize checks to see if the stat st_size can be trusted and
+ *  if not to call a routine to get the correct size.
+ *
+ */
+static curl_off_t VmsSpecialSize(const char * name,
+                                 const struct_stat * stat_buf)
+{
+  switch(stat_buf->st_fab_rfm) {
+  case FAB$C_VAR:
+  case FAB$C_VFC:
+    return VmsRealFileSize(name, stat_buf);
+    break;
+  default:
+    return stat_buf->st_size;
+  }
+}
+
+#endif
+
+#ifndef __VMS
+#define filesize(name, stat_data) (stat_data.st_size)
+#else
+    /* Getting the expected file size needs help on VMS */
+#define filesize(name, stat_data) VmsSpecialSize(name, &stat_data)
+#endif
+
 /*
  * AddFormData() adds a chunk of data to the FormData linked list.
  *
@@ -829,7 +893,7 @@ static CURLcode AddFormData(struct FormData **formp,
       if(!strequal("-", newform->line)) {
         struct_stat file;
         if(!stat(newform->line, &file) && !S_ISDIR(file.st_mode))
-          *size += file.st_size;
+          *size += filesize(newform->line, file);
         else
           return CURLE_BAD_FUNCTION_ARGUMENT;
       }
@@ -1340,6 +1404,36 @@ int Curl_FormInit(struct Form *form, struct FormData *formdata )
   return 0;
 }
 
+#ifndef __VMS
+# define fopen_read fopen
+#else
+  /*
+   * vmsfopenread
+   *
+   * For upload to work as expected on VMS, different optional
+   * parameters must be added to the fopen command based on
+   * record format of the file.
+   *
+   */
+# define fopen_read vmsfopenread
+static FILE * vmsfopenread(const char *file, const char *mode) {
+  struct_stat statbuf;
+  int result;
+
+  result = stat(file, &statbuf);
+
+  switch (statbuf.st_fab_rfm) {
+  case FAB$C_VAR:
+  case FAB$C_VFC:
+  case FAB$C_STMCR:
+    return fopen(file, "r");
+    break;
+  default:
+    return fopen(file, "r", "rfm=stmlf", "ctx=stm");
+  }
+}
+#endif
+
 /*
  * readfromfile()
  *
@@ -1362,7 +1456,7 @@ static size_t readfromfile(struct Form *form, char *buffer,
   else {
     if(!form->fp) {
       /* this file hasn't yet been opened */
-      form->fp = fopen(form->data->line, "rb"); /* b is for binary */
+      form->fp = fopen_read(form->data->line, "rb"); /* b is for binary */
       if(!form->fp)
         return (size_t)-1; /* failure */
     }