new -lutil, only openpty() for now

lib/util/Makefile

@@ -0,0 +1,19 @@
+# Makefile for lib/util.
+
+CFLAGS	= -O -D_MINIX -D_POSIX_SOURCE
+CC1	= $(CC) $(CFLAGS) -c
+
+LIBUTIL	= ../libutil.a
+all:	$(LIBUTIL)
+
+OBJECTS	= \
+	$(LIBUTIL)(openpty.o) 
+	 
+
+$(LIBUTIL):	$(OBJECTS)
+	aal cr $@ *.o
+	rm *.o
+
+$(LIBUTIL)(openpty.o):	openpty.c
+	$(CC1) openpty.c
+

lib/util/openpty.c

@@ -0,0 +1,83 @@
+/*
+ * openpty() tries to open a pty; applications won't have to
+ * duplicate this code all the time (or change it if the system
+ * pty interface changes).
+ *
+ * First version by Ben Gras <beng@few.vu.nl>,
+ * Initially heavily based on telnetd/pty.c
+ * by Fred N. van Kempen, <waltje@uwalt.nl.mugnet.org>.
+ *
+ */
+#include <libutil.h>
+#include <termios.h>
+#include <fcntl.h>
+#include <grp.h>
+#include <string.h>
+#include <stdlib.h>
+#include <errno.h>
+#include <stdio.h>
+#include <unistd.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <sys/ioc_tty.h>
+
+#define DEV_DIR		"/dev"
+
+/*
+ * Allocate a PTY, by trying to open one repeatedly.
+ */
+int openpty(int *amaster, int *aslave, char *name,
+	struct termios *termp, struct winsize *winp)
+{
+  char buff[128], temp[128];
+  register int i, j;
+  int pty_fd = -1, gr;
+  static char tty_name[128];
+  struct group *ttygroup;
+  gid_t tty_gid = 0;
+
+  if(!amaster || !aslave) {
+  	errno = EINVAL;
+  	return -1;
+  }
+
+  for(i = 'p'; i < 'w'; i++) {
+	j = 0;
+	do {
+		sprintf(buff, "%s/pty%c%c",
+			DEV_DIR, i, (j < 10) ? j + '0' : j + 'a' - 10);
+
+		if((*amaster = open(buff, O_RDWR)) >= 0) {
+		  sprintf(tty_name, "%s/tty%c%c", DEV_DIR,
+			i, (j < 10) ? j + '0' : j + 'a' - 10);
+		  if((*aslave = open(tty_name, O_RDWR)) >= 0) {
+		  	break;
+		  }
+		  close(*amaster);
+		}
+
+		j++;
+		if (j == 16) break;
+	} while(1);
+
+	/* Did we find one? */
+	if (j < 16) break;
+  }
+  if (*amaster < 0) { errno = ENOENT; return(-1); }
+
+  setgrent();
+  ttygroup = getgrnam("tty");
+  endgrent();
+  if(ttygroup) tty_gid = ttygroup->gr_gid;
+
+  if(name) strcpy(name, tty_name);
+
+  /* Ignore errors on these. */
+  chown(tty_name, getuid(), tty_gid);
+  chmod(tty_name, 0620);	/* -rw--w---- */
+  if(termp) tcsetattr(*aslave, TCSAFLUSH, termp);
+  if(winp) ioctl(*aslave, TIOCSWINSZ, winp);
+
+  return(0);
+}
+