threads/76938: include/unistd.h: ttyname_r prototype missing

[Craig Rodrigues]

The following reply was made to PR threads/76938; it has been noted by GNATS.

From: Craig Rodrigues <rodrigc at crodrigues.org>
To: freebsd-gnats-submit at freebsd.org
Cc: tmclaugh at sdf.lonestar.org
Subject: Re: threads/76938: include/unistd.h: ttyname_r prototype missing
Date: Thu, 17 Mar 2005 20:19:51 -0500

 Hi,
 
 Poul-Henning recently modified ttyname, but still kept
 our non-standard ttyname_r, so I am submitting
 a modified patch.
 
 --- lib/libc/gen/ttyname.3.orig	Wed Mar  9 17:13:58 2005
 +++ lib/libc/gen/ttyname.3	Thu Mar 17 20:00:02 2005
 @@ -37,6 +37,7 @@
  .Os
  .Sh NAME
  .Nm ttyname ,
 +.Nm ttyname_r ,
  .Nm isatty ,
  .Nm ttyslot
  .Nd get name of associated terminal (tty) from file descriptor
 @@ -46,7 +47,7 @@
  .In unistd.h
  .Ft char *
  .Fn ttyname "int fd"
 -.Ft char *
 +.Ft int
  .Fn ttyname_r "int fd" "char *buf" "size_t len"
  .Ft int
  .Fn isatty "int fd"
 @@ -82,7 +83,13 @@
  gets the related device name of
  a file descriptor for which
  .Fn isatty
 -is true
 +is true.
 +.Pp
 +.Fn ttyname
 +returns the name stored in a static buffer which will be overwritten
 +on subsequent calls.
 +.Fn ttyname_r
 +takes a buffer and length as arguments to avoid this problem.
  .Pp
  The
  .Fn ttyslot
 @@ -100,12 +107,25 @@
  a
  .Dv NULL
  pointer is returned.
 +The
 +.Fn ttyname_r
 +function returns 0 if successful.  Otherwise an error number is returned.
  .Pp
  The
  .Fn ttyslot
  function
  returns the unit number of the device file if found; otherwise
  the value zero is returned.
 +.Sh ERRORS
 +.Fn ttyname_r
 +may return the following error codes:
 +.Bl -tag -width Er
 +.It Bq Er ENOTTY
 +.Fa fd
 +is not a valid file descriptor.
 +.It Bq Er ERANGE
 +.Fa bufsize
 +is smaller than the length of the string to be returned.
  .Sh FILES
  .Bl -tag -width /etc/ttys -compact
  .It Pa /dev/\(**
 @@ -123,11 +143,6 @@
  function
  appeared in
  .At v7 .
 -.Sh BUGS
 -The
 -.Fn ttyname
 -function leaves its result in an internal static object and returns
 -a pointer to that object.
 -Subsequent calls to
 -.Fn ttyname
 -will modify the same object.
 +.Fn ttyname_r
 +appeared in
 +.Fx 6.0 .
 --- lib/libc/gen/ttyname.c.orig	Thu Mar 17 10:39:08 2005
 +++ lib/libc/gen/ttyname.c	Thu Mar 17 11:15:42 2005
 @@ -50,6 +50,7 @@
  #include <string.h>
  #include <paths.h>
  #include <pthread.h>
 +#include <errno.h>
  #include "un-namespace.h"
  
  #include "libc_private.h"
 @@ -60,34 +61,32 @@
  static pthread_key_t	ttyname_key;
  static int		ttyname_init = 0;
  
 -char *
 +int
  ttyname_r(int fd, char *buf, size_t len)
  {
  	struct stat	sb;
 -	char		*rval;
  	struct fiodgname_arg fgn;
  
 -	rval = NULL;
  	*buf = '\0';
  
  	/* Must be a terminal. */
  	if (!isatty(fd))
 -		return (rval);
 +		return (ENOTTY);
  	/* Must be a character device. */
  	if (_fstat(fd, &sb) || !S_ISCHR(sb.st_mode))
 -		return (rval);
 +		return (ENOTTY);
  	/* Must have enough room */
  	if (len <= sizeof(_PATH_DEV))
 -		return (rval);
 +		return (ERANGE);
  
  	strcpy(buf, _PATH_DEV);
  	fgn.len = len - strlen(buf);
  	fgn.buf = buf + strlen(buf);
  	if (!_ioctl(fd, FIODGNAME, &fgn))
 -		return(buf);
 +		return (EINVAL);
  	devname_r(sb.st_rdev, S_IFCHR,
  	    buf + strlen(buf), sizeof(buf) - strlen(buf));
 -	return (buf);
 +	return (0);
  }
  
  char *
 @@ -95,8 +94,12 @@
  {
  	char	*buf;
  
 -	if (__isthreaded == 0)
 -		return (ttyname_r(fd, ttyname_buf, sizeof ttyname_buf));
 +	if (__isthreaded == 0) {
 +		if (ttyname_r(fd, ttyname_buf, sizeof ttyname_buf) != 0)
 +			return (NULL);
 +		else
 +			return (ttyname_buf);
 +	}
  
  	if (ttyname_init == 0) {
  		_pthread_mutex_lock(&ttyname_lock);
 @@ -121,6 +124,7 @@
  			return (NULL);
  		}
  	}
 -	return (ttyname_r(fd, buf, sizeof(_PATH_DEV) + MAXNAMLEN));
 +	ttyname_r(fd, buf, sizeof(_PATH_DEV) + MAXNAMLEN);
 +	return (buf);
  }
  
 --- include/unistd.h.orig	Thu Feb 17 17:37:41 2005
 +++ include/unistd.h	Thu Feb 17 17:38:19 2005
 @@ -365,6 +365,7 @@
  pid_t	 tcgetpgrp(int);
  int	 tcsetpgrp(int, pid_t);
  char	*ttyname(int);
 +int	ttyname_r(int, char *, size_t);
  int	 unlink(const char *);
  ssize_t	 write(int, const void *, size_t);
 
 
 
 -- 
 Craig Rodrigues        
 rodrigc at crodrigues.org