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* fports.c (scm_fdes_to_port): call fcntl F_GETFL to test that

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the fdes is valid before doing anything else.  check that
	the file descriptor supports the modes required.
	(scm_fport_buffer_add): don't throw an error if fstat doesn't
	work: just use the default buffer size.

	* throw.c: change an outdated comment about scm_internal_catch
	BODY: it doesn't take a jumpbuf arg.

	* init.c (scm_standard_stream_to_port): install a handler in case
	scm_fdes_to_port throws an error.  don't check here whether the
	file descriptor is valid, since scm_fdes_to_port will do that.
	set the revealed count depending on whether the port got the
	standard file descriptor.
	(stream_body_data): new type.
	(stream_body, stream_handler): new procs.
This commit is contained in:
Gary Houston 2000-03-12 19:58:56 +00:00
parent f8a72ca4c9
commit 19b27fa236
4 changed files with 85 additions and 37 deletions
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79
libguile/init.c
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@ -248,32 +248,69 @@ check_config (void)
/* initializing standard and current I/O ports */
/* Like scm_fdes_to_port, except that:
- NAME is a standard C string, not a Guile string
- we set the revealed count for FILE's file descriptor to 1, so
that FDES won't be closed when the port object is GC'd.
- when FDES is not a valid file descripter (as determined by
fstat), we open "/dev/null" and use that instead. In that case,
the revealed count is left at zero.
*/
typedef struct
{
int fdes;
char *mode;
char *name;
} stream_body_data;
/* proc to be called in scope of exception handler stream_handler. */
static SCM
stream_body (void *data)
{
stream_body_data *body_data = (stream_body_data *) data;
SCM port = scm_fdes_to_port (body_data->fdes, body_data->mode,
scm_makfrom0str (body_data->name));
SCM_REVEALED (port) = 1;
return port;
}
/* exception handler for stream_body. */
static SCM
stream_handler (void *data, SCM tag, SCM throw_args)
{
return SCM_BOOL_F;
}
/* Convert a file descriptor to a port, using scm_fdes_to_port.
- NAME is a C string, not a Guile string
- set the revealed count for FILE's file descriptor to 1, so
that fdes won't be closed when the port object is GC'd.
- catch exceptions: allow Guile to be able to start up even
if it has been handed bogus stdin/stdout/stderr. In this case
try to open a new stream on /dev/null. */
static SCM
scm_standard_stream_to_port (int fdes, char *mode, char *name)
{
struct stat st;
if (fstat (fdes, &st) == -1)
{
/* We do not bother to check errno. When fstat fails, there is
generally no point in trying to use FDES, I think. */
SCM port;
stream_body_data body_data;
fdes = open ("/dev/null", (mode[0] == 'r')? O_RDONLY : O_WRONLY);
return scm_fdes_to_port (fdes, mode, scm_makfrom0str (name));
}
else
body_data.fdes = fdes;
body_data.mode = mode;
body_data.name = name;
port = scm_internal_catch (SCM_BOOL_T, stream_body, &body_data,
stream_handler, NULL);
if (SCM_FALSEP (port))
{
SCM port = scm_fdes_to_port (fdes, mode, scm_makfrom0str (name));
scm_set_port_revealed_x (port, SCM_MAKINUM (1));
return port;
}
/* FIXME: /dev/null portability. there's also *null-device* in
r4rs.scm. */
int null_fdes = open ("/dev/null",
(mode[0] == 'r') ? O_RDONLY : O_WRONLY);
body_data.fdes = null_fdes;
port = (null_fdes == -1) ? SCM_BOOL_F
: scm_internal_catch (SCM_BOOL_T, stream_body, &body_data,
stream_handler, NULL);
/* if the standard fdes was not allocated, reset the revealed count
on the grounds that the user doesn't know what it is. */
if (SCM_NFALSEP (port) && null_fdes != fdes)
SCM_REVEALED (port) = 0;
/* if port is still #f, we'll just leave it like that and
an error will be raised on the first attempt to use it. */
}
return port;
}
/* Create standard ports from stdin, stdout, and stderr. */