/*
* Handle the mapping of uid/gid and user/group names between systems.
*
* Copyright (C) 1996 Andrew Tridgell
* Copyright (C) 1996 Paul Mackerras
* Copyright (C) 2004-2009 Wayne Davison
*
* 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 3 of the License, 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, visit the http://fsf.org website.
*/
/* If the source username/group does not exist on the target then use
* the numeric IDs. Never do any mapping for uid=0 or gid=0 as these
* are special. */
#include "rsync.h"
#include "io.h"
extern int verbose;
extern int am_root;
extern int preserve_uid;
extern int preserve_gid;
extern int preserve_acls;
extern int numeric_ids;
#ifdef HAVE_GETGROUPS
# ifndef GETGROUPS_T
# define GETGROUPS_T gid_t
# endif
#endif
struct idlist {
struct idlist *next;
const char *name;
id_t id, id2;
uint16 flags;
};
static struct idlist *uidlist;
static struct idlist *gidlist;
static struct idlist *add_to_list(struct idlist **root, id_t id, const char *name,
id_t id2, uint16 flags)
{
struct idlist *node = new(struct idlist);
if (!node)
out_of_memory("add_to_list");
node->next = *root;
node->name = name;
node->id = id;
node->id2 = id2;
node->flags = flags;
*root = node;
return node;
}
/* turn a uid into a user name */
static const char *uid_to_name(uid_t uid)
{
struct passwd *pass = getpwuid(uid);
if (pass)
return strdup(pass->pw_name);
return NULL;
}
/* turn a gid into a group name */
static const char *gid_to_name(gid_t gid)
{
struct group *grp = getgrgid(gid);
if (grp)
return strdup(grp->gr_name);
return NULL;
}
static uid_t map_uid(uid_t id, const char *name)
{
uid_t uid;
if (id != 0 && name_to_uid(name, &uid))
return uid;
return id;
}
static gid_t map_gid(gid_t id, const char *name)
{
gid_t gid;
if (id != 0 && name_to_gid(name, &gid))
return gid;
return id;
}
static int is_in_group(gid_t gid)
{
#ifdef HAVE_GETGROUPS
static gid_t last_in;
static int ngroups = -2, last_out = -1;
static GETGROUPS_T *gidset;
int n;
if (gid == last_in && last_out >= 0)
return last_out;
if (ngroups < -1) {
gid_t mygid = MY_GID();
if ((ngroups = getgroups(0, NULL)) < 0)
ngroups = 0;
gidset = new_array(GETGROUPS_T, ngroups+1);
if (!gidset)
out_of_memory("is_in_group");
if (ngroups > 0)
ngroups = getgroups(ngroups, gidset);
/* The default gid might not be in the list on some systems. */
for (n = 0; n < ngroups; n++) {
if (gidset[n] == mygid)
break;
}
if (n == ngroups)
gidset[ngroups++] = mygid;
if (verbose > 3) {
int pos;
char *gidbuf = new_array(char, ngroups*21+32);
if (!gidbuf)
out_of_memory("is_in_group");
pos = snprintf(gidbuf, 32, "process has %d gid%s: ",
ngroups, ngroups == 1? "" : "s");
for (n = 0; n < ngroups; n++) {
pos += snprintf(gidbuf+pos, 21, " %d", (int)gidset[n]);
}
rprintf(FINFO, "%s\n", gidbuf);
free(gidbuf);
}
}
last_in = gid;
for (n = 0; n < ngroups; n++) {
if (gidset[n] == gid)
return last_out = 1;
}
return last_out = 0;
#else
static gid_t mygid = GID_NONE;
if (mygid == GID_NONE) {
mygid = MY_GID();
if (verbose > 3)
rprintf(FINFO, "process has gid %u\n", (unsigned)mygid);
}
return gid == mygid;
#endif
}
/* Add a uid to the list of uids. Only called on receiving side. */
static struct idlist *recv_add_uid(uid_t id, const char *name)
{
uid_t id2 = name ? map_uid(id, name) : id;
struct idlist *node;
node = add_to_list(&uidlist, id, name, id2, 0);
if (verbose > 3) {
rprintf(FINFO, "uid %u(%s) maps to %u\n",
(unsigned)id, name ? name : "", (unsigned)id2);
}
return node;
}
/* Add a gid to the list of gids. Only called on receiving side. */
static struct idlist *recv_add_gid(gid_t id, const char *name)
{
gid_t id2 = name ? map_gid(id, name) : id;
struct idlist *node;
node = add_to_list(&gidlist, id, name, id2,
!am_root && !is_in_group(id2) ? FLAG_SKIP_GROUP : 0);
if (verbose > 3) {
rprintf(FINFO, "gid %u(%s) maps to %u\n",
(unsigned)id, name ? name : "", (unsigned)id2);
}
return node;
}
/* this function is a definate candidate for a faster algorithm */
uid_t match_uid(uid_t uid)
{
static uid_t last_in, last_out;
struct idlist *list;
if (uid == 0)
return 0;
if (uid == last_in)
return last_out;
last_in = uid;
for (list = uidlist; list; list = list->next) {
if (list->id == uid)
return last_out = list->id2;
}
return last_out = uid;
}
gid_t match_gid(gid_t gid, uint16 *flags_ptr)
{
static struct idlist *last = NULL;
struct idlist *list;
if (last && gid == last->id)
list = last;
else {
for (list = gidlist; list; list = list->next) {
if (list->id == gid)
break;
}
if (!list)
list = recv_add_gid(gid, NULL);
last = list;
}
if (flags_ptr && list->flags & FLAG_SKIP_GROUP)
*flags_ptr |= FLAG_SKIP_GROUP;
return list->id2;
}
/* Add a uid to the list of uids. Only called on sending side. */
const char *add_uid(uid_t uid)
{
struct idlist *list;
struct idlist *node;
if (uid == 0) /* don't map root */
return NULL;
for (list = uidlist; list; list = list->next) {
if (list->id == uid)
return NULL;
}
node = add_to_list(&uidlist, uid, uid_to_name(uid), 0, 0);
return node->name;
}
/* Add a gid to the list of gids. Only called on sending side. */
const char *add_gid(gid_t gid)
{
struct idlist *list;
struct idlist *node;
if (gid == 0) /* don't map root */
return NULL;
for (list = gidlist; list; list = list->next) {
if (list->id == gid)
return NULL;
}
node = add_to_list(&gidlist, gid, gid_to_name(gid), 0, 0);
return node->name;
}
/* send a complete uid/gid mapping to the peer */
void send_id_list(int f)
{
struct idlist *list;
if (preserve_uid || preserve_acls) {
int len;
/* we send sequences of uid/byte-length/name */
for (list = uidlist; list; list = list->next) {
if (!list->name)
continue;
len = strlen(list->name);
write_varint30(f, list->id);
write_byte(f, len);
write_buf(f, list->name, len);
}
/* terminate the uid list with a 0 uid. We explicitly exclude
* 0 from the list */
write_varint30(f, 0);
}
if (preserve_gid || preserve_acls) {
int len;
for (list = gidlist; list; list = list->next) {
if (!list->name)
continue;
len = strlen(list->name);
write_varint30(f, list->id);
write_byte(f, len);
write_buf(f, list->name, len);
}
write_varint30(f, 0);
}
}
uid_t recv_user_name(int f, uid_t uid)
{
struct idlist *node;
int len = read_byte(f);
char *name = new_array(char, len+1);
if (!name)
out_of_memory("recv_user_name");
read_sbuf(f, name, len);
if (numeric_ids < 0) {
free(name);
name = NULL;
}
node = recv_add_uid(uid, name); /* node keeps name's memory */
return node->id2;
}
gid_t recv_group_name(int f, gid_t gid, uint16 *flags_ptr)
{
struct idlist *node;
int len = read_byte(f);
char *name = new_array(char, len+1);
if (!name)
out_of_memory("recv_group_name");
read_sbuf(f, name, len);
if (numeric_ids < 0) {
free(name);
name = NULL;
}
node = recv_add_gid(gid, name); /* node keeps name's memory */
if (flags_ptr && node->flags & FLAG_SKIP_GROUP)
*flags_ptr |= FLAG_SKIP_GROUP;
return node->id2;
}
/* recv a complete uid/gid mapping from the peer and map the uid/gid
* in the file list to local names */
void recv_id_list(int f, struct file_list *flist)
{
id_t id;
int i;
if ((preserve_uid || preserve_acls) && numeric_ids <= 0) {
/* read the uid list */
while ((id = read_varint30(f)) != 0)
recv_user_name(f, id);
}
if ((preserve_gid || preserve_acls) && numeric_ids <= 0) {
/* read the gid list */
while ((id = read_varint30(f)) != 0)
recv_group_name(f, id, NULL);
}
/* Now convert all the uids/gids from sender values to our values. */
#ifdef SUPPORT_ACLS
if (preserve_acls && !numeric_ids)
match_acl_ids();
#endif
if (am_root && preserve_uid && !numeric_ids) {
for (i = 0; i < flist->used; i++)
F_OWNER(flist->files[i]) = match_uid(F_OWNER(flist->files[i]));
}
if (preserve_gid && (!am_root || !numeric_ids)) {
for (i = 0; i < flist->used; i++) {
F_GROUP(flist->files[i]) = match_gid(F_GROUP(flist->files[i]),
&flist->files[i]->flags);
}
}
}
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