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authorSergey Poznyakoff <gray@gnu.org.ua>2004-02-27 13:28:40 +0000
committerSergey Poznyakoff <gray@gnu.org.ua>2004-02-27 13:28:40 +0000
commita783e2c18c6b566b2f4c2b06e6c388a9645c826c (patch)
treeae12abc157dee99bd4c67bab25316be06d3519a2 /src/userspec.c
parentcb721df9888a296af824a4acab4916694d6dc35d (diff)
downloadcpio-a783e2c18c6b566b2f4c2b06e6c388a9645c826c.tar.gz
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+/* userspec.c -- Parse a user and group string.
+ Copyright (C) 1989, 1990, 1991, 1992, 2001 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.,
+ 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */
+
+/* Written by David MacKenzie <djm@gnu.ai.mit.edu>. */
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+
+#include "system.h"
+
+#ifdef __GNUC__
+#define alloca __builtin_alloca
+#else
+#ifdef HAVE_ALLOCA_H
+#include <alloca.h>
+#else
+#ifdef _AIX
+ #pragma alloca
+#else
+char *alloca ();
+#endif
+#endif
+#endif
+
+#include <stdio.h>
+#include <ctype.h>
+#include <sys/types.h>
+#include <pwd.h>
+#include <grp.h>
+
+#if !HAVE_DECL_GETPWNAM
+extern struct passwd *getpwnam (const char *name);
+#endif
+#if !HAVE_DECL_GETGRNAM
+extern struct group *getgrnam (const char *name);
+#endif
+#if !HAVE_DECL_GETGRGID
+extern struct group *getgrgid (gid_t gid);
+#endif
+
+#ifndef HAVE_ENDPWENT
+# define endpwent()
+#endif
+#ifndef HAVE_ENDGRENT
+# define endgrent()
+#endif
+
+/* Perform the equivalent of the statement `dest = strdup (src);',
+ but obtaining storage via alloca instead of from the heap. */
+
+#define V_STRDUP(dest, src) \
+ do \
+ { \
+ int _len = strlen ((src)); \
+ (dest) = (char *) alloca (_len + 1); \
+ strcpy (dest, src); \
+ } \
+ while (0)
+
+/* Return nonzero if STR represents an unsigned decimal integer,
+ otherwise return 0. */
+
+static int
+isnumber (str)
+ const char *str;
+{
+ for (; *str; str++)
+ if (!isdigit (*str))
+ return 0;
+ return 1;
+}
+
+/* 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.
+
+ Return NULL if successful, a static error message string if not. */
+
+const char *
+parse_user_spec (spec_arg, uid, gid, username_arg, groupname_arg)
+ const char *spec_arg;
+ uid_t *uid;
+ gid_t *gid;
+ char **username_arg, **groupname_arg;
+{
+ static const char *tired = "virtual memory exhausted";
+ const char *error_msg;
+ char *spec; /* A copy we can write on. */
+ struct passwd *pwd;
+ struct group *grp;
+ char *g, *u, *separator;
+ char *groupname;
+
+ error_msg = NULL;
+ *username_arg = *groupname_arg = NULL;
+ groupname = NULL;
+
+ V_STRDUP (spec, spec_arg);
+
+ /* Find the separator if there is one. */
+ separator = index (spec, ':');
+ if (separator == NULL)
+ separator = index (spec, '.');
+
+ /* Replace separator with a NUL. */
+ if (separator != NULL)
+ *separator = '\0';
+
+ /* Set U and G to non-zero length strings corresponding to user and
+ group specifiers or to NULL. */
+ u = (*spec == '\0' ? NULL : spec);
+
+ g = (separator == NULL || *(separator + 1) == '\0'
+ ? NULL
+ : separator + 1);
+
+ if (u == NULL && g == NULL)
+ return "can not omit both user and group";
+
+ if (u != NULL)
+ {
+ pwd = getpwnam (u);
+ if (pwd == NULL)
+ {
+
+ if (!isnumber (u))
+ error_msg = _("invalid user");
+ else
+ {
+ int use_login_group;
+ use_login_group = (separator != NULL && g == NULL);
+ if (use_login_group)
+ error_msg = _("cannot get the login group of a numeric UID");
+ else
+ *uid = atoi (u);
+ }
+ }
+ else
+ {
+ *uid = pwd->pw_uid;
+ if (g == NULL && separator != NULL)
+ {
+ /* A separator was given, but a group was not specified,
+ so get the login group. */
+ *gid = pwd->pw_gid;
+ grp = getgrgid (pwd->pw_gid);
+ if (grp == NULL)
+ {
+ /* This is enough room to hold the unsigned decimal
+ representation of any 32-bit quantity and the trailing
+ zero byte. */
+ char uint_buf[21];
+ sprintf (uint_buf, "%u", (unsigned) (pwd->pw_gid));
+ V_STRDUP (groupname, uint_buf);
+ }
+ else
+ {
+ V_STRDUP (groupname, grp->gr_name);
+ }
+ endgrent ();
+ }
+ }
+ endpwent ();
+ }
+
+ if (g != NULL && error_msg == NULL)
+ {
+ /* Explicit group. */
+ grp = getgrnam (g);
+ if (grp == NULL)
+ {
+ if (!isnumber (g))
+ error_msg = _("invalid group");
+ else
+ *gid = atoi (g);
+ }
+ else
+ *gid = grp->gr_gid;
+ endgrent (); /* Save a file descriptor. */
+
+ if (error_msg == NULL)
+ V_STRDUP (groupname, g);
+ }
+
+ if (error_msg == NULL)
+ {
+ if (u != NULL)
+ {
+ *username_arg = strdup (u);
+ if (*username_arg == NULL)
+ error_msg = tired;
+ }
+
+ if (groupname != NULL && error_msg == NULL)
+ {
+ *groupname_arg = strdup (groupname);
+ if (*groupname_arg == NULL)
+ {
+ if (*username_arg != NULL)
+ {
+ free (*username_arg);
+ *username_arg = NULL;
+ }
+ error_msg = tired;
+ }
+ }
+ }
+
+ return error_msg;
+}
+
+#ifdef TEST
+
+#define NULL_CHECK(s) ((s) == NULL ? "(null)" : (s))
+
+int
+main (int argc, char **argv)
+{
+ int i;
+
+ for (i = 1; i < argc; i++)
+ {
+ const char *e;
+ char *username, *groupname;
+ uid_t uid;
+ gid_t gid;
+ char *tmp;
+
+ tmp = strdup (argv[i]);
+ e = parse_user_spec (tmp, &uid, &gid, &username, &groupname);
+ free (tmp);
+ printf ("%s: %u %u %s %s %s\n",
+ argv[i],
+ (unsigned int) uid,
+ (unsigned int) gid,
+ NULL_CHECK (username),
+ NULL_CHECK (groupname),
+ NULL_CHECK (e));
+ }
+
+ exit (0);
+}
+
+#endif

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