[PATCH] Fix bug determining the mode of the io space.

[John Darrington]

---
 ChangeLog                       | 10 ++++++++++
 src/ios-dev-file.c              | 33 ++++++++++++++++++++++-----------
 src/ios-dev.h                   |  4 ++++
 src/ios.c                       |  3 +--
 src/ios.h                       |  1 +
 testsuite/poke.cmd/file-mode.pk |  8 ++++++++
 6 files changed, 46 insertions(+), 13 deletions(-)
 create mode 100644 testsuite/poke.cmd/file-mode.pk

diff --git a/ChangeLog b/ChangeLog
index ac2e02a..1cb70f5 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,13 @@
+2019-12-22 John Darrington <address@hidden>
+
+       * src/ios-dev-file.c (ios_dev_file_open): Use a more reliable
+       method to determine the file's mode.
+       (ios_dev_file_get_mode): New function.
+       * src/ios-dev.h (struct ios_dev_if) [get_mode]: New member.
+       * src/ios.c (ios_mode): Use method from implementation.
+       * src/ios.h (IOS_M_RDONLY): New macro.
+       * testsuite/poke.cmd/file-mode.pk: New file.
+
 2019-12-21 John Darrington <address@hidden>
 
        * src/pk-file.c (pk_cmd_file): Fix memory leaks and
diff --git a/src/ios-dev-file.c b/src/ios-dev-file.c
index fd8a206..8dc366c 100644
--- a/src/ios-dev-file.c
+++ b/src/ios-dev-file.c
@@ -29,6 +29,7 @@
 #include <xalloc.h>
 #include <string.h>
 
+#include "ios.h"
 #include "ios-dev.h"
 
 /* State associated with a file device.  */
@@ -37,7 +38,7 @@ struct ios_dev_file
 {
   FILE *file;
   char *filename;
-  char *mode;
+  int   mode;
 };
 
 static int
@@ -50,22 +51,23 @@ ios_dev_file_handler_p (const char *handler)
 static void *
 ios_dev_file_open (const char *handler)
 {
-  const char *mode;
   struct ios_dev_file *fio;
   FILE *f;
+  int mode = IOS_M_RDWR;
 
   /* Skip the file:// part in the handler, if needed.  */
   if (strlen (handler) >= 7
       && strncmp (handler, "file://", 7) == 0)
     handler += 7;
 
-  /* Open the requested file.  The open mode is read-write if
-     possible.  Otherwise read-only.  */
-
-  mode =
-    access (handler, R_OK | W_OK) != 0 ? "rb" : "r+b";
-
-  f = fopen (handler, mode);
+  /* Open the requested file.  Try read-write initially.
+     If that fails, then try read-only. */
+  f = fopen (handler, "r+b");
+  if (!f)
+    {
+      f = fopen (handler, "rb");
+      mode = IOS_M_RDONLY;
+    }
   if (!f)
     {
       perror (handler);
@@ -75,7 +77,7 @@ ios_dev_file_open (const char *handler)
   fio = xmalloc (sizeof (struct ios_dev_file));
   fio->file = f;
   fio->filename = xstrdup (handler);
-  fio->mode = xstrdup (mode);
+  fio->mode = mode;
 
   return fio;
 }
@@ -88,12 +90,20 @@ ios_dev_file_close (void *iod)
   if (fclose (fio->file) != 0)
     perror (fio->filename);
   free (fio->filename);
-  free (fio->mode);
 
   return 1;
 }
 
 static int
+ios_dev_file_get_mode (void *iod)
+{
+  struct ios_dev_file *fio = iod;
+
+  return fio->mode;
+}
+
+
+static int
 ios_dev_file_getc (void *iod)
 {
   struct ios_dev_file *fio = iod;
@@ -145,4 +155,5 @@ struct ios_dev_if ios_dev_file =
    .seek = ios_dev_file_seek,
    .get_c = ios_dev_file_getc,
    .put_c = ios_dev_file_putc,
+   .get_mode = ios_dev_file_get_mode,
   };
diff --git a/src/ios-dev.h b/src/ios-dev.h
index 7f8579d..432a219 100644
--- a/src/ios-dev.h
+++ b/src/ios-dev.h
@@ -81,4 +81,8 @@ struct ios_dev_if
      the character written as an int, or IOD_EOF on error.  */
 
   int (*put_c) (void *dev, int c);
+
+  /* Return the mode of the device, as it was opened.  */
+
+  int (*get_mode) (void *dev);
 };
diff --git a/src/ios.c b/src/ios.c
index 757ada3..c3dd1e1 100644
--- a/src/ios.c
+++ b/src/ios.c
@@ -113,7 +113,6 @@ struct ios
   char *handler;
   void *dev;
   struct ios_dev_if *dev_if;
-  int mode;
 
   struct ios *next;
 };
@@ -230,7 +229,7 @@ ios_close (ios io)
 int
 ios_mode (ios io)
 {
-  return io->mode;
+  return io->dev_if->get_mode (io->dev);
 }
 
 ios_off
diff --git a/src/ios.h b/src/ios.h
index b0647f6..85055b7 100644
--- a/src/ios.h
+++ b/src/ios.h
@@ -125,6 +125,7 @@ void ios_close (ios io);
    are summarized in the IOS_M_* constants, also defined below.  */
 
 #define IOS_M_RDWR 1
+#define IOS_M_RDONLY 2
 
 int ios_mode (ios io);
 
diff --git a/testsuite/poke.cmd/file-mode.pk b/testsuite/poke.cmd/file-mode.pk
new file mode 100644
index 0000000..bb5402c
--- /dev/null
+++ b/testsuite/poke.cmd/file-mode.pk
@@ -0,0 +1,8 @@
+/* { dg-do run } */
+
+/* { dg-command { .file /etc/passwd } } */
+/* { dg-command { .file /dev/null } } */
+/* { dg-command { .info files } } */
+/* { dg-output "  Id    Mode    Position        Filename\n
+* #0    rw      0x00000000#b    file:///dev/null\n
+  #1    r       0x00000000#b    file:///etc/passwd\n" } */
-- 
2.11.0