Initial revision

1 files changed, 178 insertions, 0 deletions

diff --git a/lib/userspec.c b/lib/userspec.c
new file mode 100644
index 000000000..60c6ecc1a
--- /dev/null
+++ b/lib/userspec.c
@@ -0,0 +1,178 @@
+/* userspec.c -- Parse a user and group string.
+   Copyright (C) 1989, 1990, 1991, 1992 Free Software Foundation, Inc.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 2, or (at your option)
+   any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program; if not, write to the Free Software
+   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.  */
+
+/* Written by David MacKenzie <djm@gnu.ai.mit.edu>.  */
+
+#include <stdio.h>
+#include <sys/types.h>
+#include <pwd.h>
+#include <grp.h>
+
+#if defined(USG) || defined(STDC_HEADERS)
+#include <string.h>
+#define index strchr
+#else
+#include <strings.h>
+#endif
+
+#ifdef STDC_HEADERS
+#include <stdlib.h>
+#else
+char *malloc ();
+#endif
+
+#ifdef HAVE_UNISTD_H
+#include <unistd.h>
+#endif
+
+#ifndef _POSIX_VERSION
+struct passwd *getpwnam ();
+struct group *getgrnam ();
+struct group *getgrgid ();
+#endif
+
+#ifdef _POSIX_SOURCE
+#define endpwent()
+#define endgrent()
+#endif
+
+#define isdigit(c) ((c) >= '0' && (c) <= '9')
+
+char *strdup ();
+static int isnumber ();
+
+/* Extract from NAME, which has the form "[user][:.][group]",
+   a USERNAME, UID U, GROUPNAME, and GID G.
+   Either user or group, or both, must be present.
+   If the group is omitted but the ":" or "." separator is given,
+   use the given user's login group.
+
+   USERNAME and GROUPNAME will be in newly malloc'd memory.
+   Either one might be NULL instead, indicating that it was not
+   given and the corresponding numeric ID was left unchanged.
+   Might write NULs into NAME.
+
+   Return NULL if successful, a static error message string if not.  */
+
+char *
+parse_user_spec (name, uid, gid, username, groupname)
+     char *name;
+     uid_t *uid;
+     gid_t *gid;
+     char **username, **groupname;
+{
+  static char *tired = "virtual memory exhausted";
+  struct passwd *pwd;
+  struct group *grp;
+  char *cp;
+  int use_login_group = 0;
+
+  *username = *groupname = NULL;
+
+  /* Check whether a group is given.  */
+  cp = index (name, ':');
+  if (cp == NULL)
+    cp = index (name, '.');
+  if (cp != NULL)
+    {
+      *cp++ = '\0';
+      if (*cp == '\0')
+	{
+	  if (cp == name + 1)
+	    /* Neither user nor group given, just "." or ":".  */
+	    return "can not omit both user and group";
+	  else
+	    /* "user.".  */
+	    use_login_group = 1;
+	}
+      else
+	{
+	  /* Explicit group.  */
+	  *groupname = strdup (cp);
+	  if (*groupname == NULL)
+	    return tired;
+	  grp = getgrnam (cp);
+	  if (grp == NULL)
+	    {
+	      if (!isnumber (cp))
+		return "invalid group";
+	      *gid = atoi (cp);
+	    }
+	  else
+	    *gid = grp->gr_gid;
+	  endgrent ();		/* Save a file descriptor.  */
+	}
+    }
+
+  /* Parse the user name, now that any group has been removed.  */
+
+  if (name[0] == '\0')
+    /* No user name was given, just a group.  */
+    return NULL;
+
+  *username = strdup (name);
+  if (*username == NULL)
+    return tired;
+
+  pwd = getpwnam (name);
+  if (pwd == NULL)
+    {
+      if (!isnumber (name))
+	return "invalid user";
+      if (use_login_group)
+	return "cannot get the login group of a numeric UID";
+      *uid = atoi (name);
+    }
+  else
+    {
+      *uid = pwd->pw_uid;
+      if (use_login_group)
+	{
+	  *gid = pwd->pw_gid;
+	  grp = getgrgid (pwd->pw_gid);
+	  if (grp == NULL)
+	    {
+	      *groupname = malloc (15);
+	      if (*groupname == NULL)
+		return tired;
+	      sprintf (*groupname, "%u", pwd->pw_gid);
+	    }
+	  else
+	    {
+	      *groupname = strdup (grp->gr_name);
+	      if (*groupname == NULL)
+		return tired;
+	    }
+	  endgrent ();
+	}
+    }
+  endpwent ();
+  return NULL;
+}
+
+/* Return nonzero if STR represents an unsigned decimal integer,
+   otherwise return 0. */
+
+static int
+isnumber (str)
+     char *str;
+{
+  for (; *str; str++)
+    if (!isdigit (*str))
+      return 0;
+  return 1;
+}