[PATCH] ios: avoid collision with O_RDONLY

[David Faust]

Hi!

ios_dev_file_convert_flags was returning 0 in the case of bad flags.
But, many implementations define the O_RDONLY flag for `open` as 0.
This resulted an unhandled invalid IO flags exception when attempting
to open a file with the 'open' poke builtin and IOS_M_RDONLY.

OK to install? (and probably pick to maint/poke-1?)

2021-03-26  David Faust  <david.faust@oracle.com>

        * libpoke/ios-dev-file.c (ios_dev_file_convert_flags): Return
        -1 for bad flags to avoid collision with O_RDONLY == 0.
        (ios_dev_file_open): Update flags_for_open check accordingly.
---
 ChangeLog              | 6 ++++++
 libpoke/ios-dev-file.c | 4 ++--
 2 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index 439daf69..36a1f140 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+2021-03-26  David Faust  <david.faust@oracle.com>
+
+       * libpoke/ios-dev-file.c (ios_dev_file_convert_flags): Return
+       -1 for bad flags to avoid collision with O_RDONLY == 0.
+       (ios_dev_file_open): Update flags_for_open check accordingly.
+
 2021-03-25  Jose E. Marchesi  <jemarch@gnu.org>
 
        * poke/pk-mi-msg.c (pk_mi_set_arg): An ANY msg argument can be of
diff --git a/libpoke/ios-dev-file.c b/libpoke/ios-dev-file.c
index 93d36ff4..94798419 100644
--- a/libpoke/ios-dev-file.c
+++ b/libpoke/ios-dev-file.c
@@ -87,7 +87,7 @@ ios_dev_file_convert_flags (int mode_flags, char 
**mode_for_fdopen)
     }
   else
     /* Cannot open a file neither to write nor to read.  */
-    return 0;
+    return -1;
 
   if (mode_flags & IOS_F_CREATE)
     flags_for_open |= O_CREAT;
@@ -112,7 +112,7 @@ ios_dev_file_open (const char *handler, uint64_t flags, int 
*error)
       /* Decide what mode to use to open the file.  */
       flags_for_open
         = ios_dev_file_convert_flags (mode_flags, &mode_for_fdopen);
-      if (flags_for_open == 0)
+      if (flags_for_open == -1)
         {
           internal_error = IOD_EFLAGS;
           goto err;
-- 
2.31.0