Files
android_external_rsync/xattrs.c
2007-04-07 17:22:25 +00:00

776 lines
20 KiB
C

/*
* Extended Attribute support for rsync.
* Written by Jay Fenlason, vaguely based on the ACLs patch.
*
* Copyright (C) 2004 Red Hat, Inc.
* Copyright (C) 2006, 2007 Wayne Davison
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* 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.,
* 51 Franklin Street - Fifth Floor, Boston, MA 02110-1301, USA.
*/
#include "rsync.h"
#include "lib/sysxattrs.h"
#ifdef SUPPORT_XATTRS
extern int dry_run;
extern int am_root;
extern int am_sender;
extern int am_generator;
extern int read_only;
extern int list_only;
extern int checksum_seed;
#define RSYNC_XAL_INITIAL 5
#define RSYNC_XAL_LIST_INITIAL 100
#define MAX_FULL_DATUM 32
#define HAS_PREFIX(str, prfx) (*(str) == *(prfx) \
&& strncmp(str, prfx, sizeof (prfx) - 1) == 0)
#define XATTR_ABBREV(x) ((size_t)((x).name - (x).datum) < (x).datum_len)
#define XSTATE_ABBREV 0
#define XSTATE_DONE 1
#define XSTATE_TODO 2
#define XSTATE_LOCAL 3
#define USER_PREFIX "user."
#define UPRE_LEN ((int)sizeof USER_PREFIX - 1)
#define SYSTEM_PREFIX "system."
#define SPRE_LEN ((int)sizeof SYSTEM_PREFIX - 1)
#ifdef HAVE_LINUX_XATTRS
#define RPRE_LEN 0
#else
#define RSYNC_PREFIX "rsync."
#define RPRE_LEN ((int)sizeof RSYNC_PREFIX - 1)
#endif
typedef struct {
char *datum, *name;
size_t datum_len, name_len;
} rsync_xa;
static size_t namebuf_len = 0;
static char *namebuf = NULL;
static item_list empty_xattr = EMPTY_ITEM_LIST;
static item_list rsync_xal_l = EMPTY_ITEM_LIST;
/* ------------------------------------------------------------------------- */
static void rsync_xal_free(item_list *xalp)
{
size_t i;
rsync_xa *rxas = xalp->items;
for (i = 0; i < xalp->count; i++) {
free(rxas[i].datum);
/*free(rxas[i].name);*/
}
xalp->count = 0;
}
void free_xattr(statx *sxp)
{
if (!sxp->xattr)
return;
rsync_xal_free(sxp->xattr);
free(sxp->xattr);
sxp->xattr = NULL;
}
static int rsync_xal_compare_names(const void *x1, const void *x2)
{
const rsync_xa *xa1 = x1;
const rsync_xa *xa2 = x2;
return strcmp(xa1->name, xa2->name);
}
static ssize_t get_xattr_names(const char *fname)
{
ssize_t list_len;
if (!namebuf) {
namebuf_len = 1024;
namebuf = new_array(char, namebuf_len);
if (!namebuf)
out_of_memory("get_xattr_names");
}
/* The length returned includes all the '\0' terminators. */
list_len = sys_llistxattr(fname, namebuf, namebuf_len);
if (list_len > (ssize_t)namebuf_len) {
list_len = -1;
errno = ERANGE;
}
if (list_len >= 0)
return list_len;
if (errno == ENOTSUP)
return 0;
if (errno == ERANGE) {
list_len = sys_llistxattr(fname, NULL, 0);
if (list_len < 0) {
rsyserr(FERROR, errno,
"get_xattr_names: llistxattr(\"%s\",0) failed",
fname);
return -1;
}
if (namebuf_len)
free(namebuf);
namebuf_len = list_len + 1024;
namebuf = new_array(char, namebuf_len);
if (!namebuf)
out_of_memory("get_xattr_names");
list_len = sys_llistxattr(fname, namebuf, namebuf_len);
if (list_len >= 0)
return list_len;
}
rsyserr(FERROR, errno,
"get_xattr_names: llistxattr(\"%s\",%ld) failed",
fname, (long)namebuf_len);
return -1;
}
/* On entry, the *len_ptr parameter contains the size of the extra space we
* should allocate when we create a buffer for the data. On exit, it contains
* the length of the datum. */
static char *get_xattr_data(const char *fname, const char *name, size_t *len_ptr,
int no_missing_error)
{
size_t datum_len = sys_lgetxattr(fname, name, NULL, 0);
char *ptr;
if (datum_len == (size_t)-1) {
if (errno == ENOTSUP || no_missing_error)
return NULL;
rsyserr(FERROR, errno,
"get_xattr_data: lgetxattr(\"%s\",\"%s\",0) failed",
fname, name);
return NULL;
}
if (datum_len + *len_ptr < datum_len /* checks for overflow */
|| !(ptr = new_array(char, datum_len + *len_ptr)))
out_of_memory("get_xattr_data");
*len_ptr = datum_len;
if (datum_len) {
size_t len = sys_lgetxattr(fname, name, ptr, datum_len);
if (len != datum_len) {
if (len == (size_t)-1) {
rsyserr(FERROR, errno,
"get_xattr_data: lgetxattr(\"%s\",\"%s\",%ld)"
" failed", fname, name, (long)datum_len);
} else {
rprintf(FERROR,
"get_xattr_data: lgetxattr(\"%s\",\"%s\",%ld)"
" returned %ld\n", fname, name,
(long)datum_len, (long)len);
}
free(ptr);
return NULL;
}
}
return ptr;
}
static int rsync_xal_get(const char *fname, item_list *xalp)
{
ssize_t list_len, name_len;
size_t datum_len, name_offset;
char *name, *ptr;
#ifdef HAVE_LINUX_XATTRS
int user_only = am_sender ? 0 : !am_root;
#endif
/* This puts the name list into the "namebuf" buffer. */
if ((list_len = get_xattr_names(fname)) < 0)
return -1;
for (name = namebuf; list_len > 0; name += name_len) {
rsync_xa *rxas;
name_len = strlen(name) + 1;
list_len -= name_len;
#ifdef HAVE_LINUX_XATTRS
/* We always ignore the system namespace, and non-root
* ignores everything but the user namespace. */
if (user_only ? !HAS_PREFIX(name, USER_PREFIX)
: HAS_PREFIX(name, SYSTEM_PREFIX))
continue;
#endif
datum_len = name_len; /* Pass extra size to get_xattr_data() */
if (!(ptr = get_xattr_data(fname, name, &datum_len, 0)))
return -1;
if (datum_len > MAX_FULL_DATUM) {
/* For large datums, we store a flag and a checksum. */
name_offset = 1 + MAX_DIGEST_LEN;
sum_init(checksum_seed);
sum_update(ptr, datum_len);
free(ptr);
if (!(ptr = new_array(char, name_offset + name_len)))
out_of_memory("rsync_xal_get");
*ptr = XSTATE_ABBREV;
sum_end(ptr + 1);
} else
name_offset = datum_len;
rxas = EXPAND_ITEM_LIST(xalp, rsync_xa, RSYNC_XAL_INITIAL);
rxas->name = ptr + name_offset;
memcpy(rxas->name, name, name_len);
rxas->datum = ptr;
rxas->name_len = name_len;
rxas->datum_len = datum_len;
}
if (xalp->count > 1)
qsort(xalp->items, xalp->count, sizeof (rsync_xa), rsync_xal_compare_names);
return 0;
}
/* Read the xattr(s) for this filename. */
int get_xattr(const char *fname, statx *sxp)
{
sxp->xattr = new(item_list);
*sxp->xattr = empty_xattr;
if (rsync_xal_get(fname, sxp->xattr) < 0) {
free_xattr(sxp);
return -1;
}
return 0;
}
static int find_matching_xattr(item_list *xalp)
{
size_t i, j;
item_list *lst = rsync_xal_l.items;
for (i = 0; i < rsync_xal_l.count; i++) {
rsync_xa *rxas1 = lst[i].items;
rsync_xa *rxas2 = xalp->items;
/* Wrong number of elements? */
if (lst[i].count != xalp->count)
continue;
/* any elements different? */
for (j = 0; j < xalp->count; j++) {
if (rxas1[j].name_len != rxas2[j].name_len
|| rxas1[j].datum_len != rxas2[j].datum_len
|| strcmp(rxas1[j].name, rxas2[j].name))
break;
if (rxas1[j].datum_len > MAX_FULL_DATUM) {
if (memcmp(rxas1[j].datum + 1,
rxas2[j].datum + 1,
MAX_DIGEST_LEN) != 0)
break;
} else {
if (memcmp(rxas1[j].datum, rxas2[j].datum,
rxas2[j].datum_len))
break;
}
}
/* no differences found. This is The One! */
if (j == xalp->count)
return i;
}
return -1;
}
/* Store *xalp on the end of rsync_xal_l */
static void rsync_xal_store(item_list *xalp)
{
item_list *new_lst = EXPAND_ITEM_LIST(&rsync_xal_l, item_list, RSYNC_XAL_LIST_INITIAL);
/* Since the following call starts a new list, we know it will hold the
* entire initial-count, not just enough space for one new item. */
*new_lst = empty_xattr;
(void)EXPAND_ITEM_LIST(new_lst, rsync_xa, xalp->count);
memcpy(new_lst->items, xalp->items, xalp->count * sizeof (rsync_xa));
new_lst->count = xalp->count;
xalp->count = 0;
}
/* Send the make_xattr()-generated xattr list for this flist entry. */
int send_xattr(statx *sxp, int f)
{
int ndx = find_matching_xattr(sxp->xattr);
/* Send 0 (-1 + 1) to indicate that literal xattr data follows. */
write_abbrevint(f, ndx + 1);
if (ndx < 0) {
rsync_xa *rxa;
int count = sxp->xattr->count;
write_abbrevint(f, count);
for (rxa = sxp->xattr->items; count--; rxa++) {
#ifdef HAVE_LINUX_XATTRS
write_abbrevint(f, rxa->name_len);
write_abbrevint(f, rxa->datum_len);
write_buf(f, rxa->name, rxa->name_len);
#else
/* We strip the rsync prefix from disguised namespaces
* and put everything else in the user namespace. */
if (HAS_PREFIX(rxa->name, RSYNC_PREFIX)
&& rxa->name[RPRE_LEN] != '%') {
write_abbrevint(f, rxa->name_len - RPRE_LEN);
write_abbrevint(f, rxa->datum_len);
write_buf(f, rxa->name + RPRE_LEN, rxa->name_len - RPRE_LEN);
} else {
write_abbrevint(f, rxa->name_len + UPRE_LEN);
write_abbrevint(f, rxa->datum_len);
write_buf(f, USER_PREFIX, UPRE_LEN);
write_buf(f, rxa->name, rxa->name_len);
}
#endif
if (rxa->datum_len > MAX_FULL_DATUM)
write_buf(f, rxa->datum + 1, MAX_DIGEST_LEN);
else
write_buf(f, rxa->datum, rxa->datum_len);
}
ndx = rsync_xal_l.count; /* pre-incremented count */
rsync_xal_store(sxp->xattr); /* adds item to rsync_xal_l */
}
return ndx;
}
/* Return a flag indicating if we need to change a file's xattrs. If
* "find_all" is specified, also mark any abbreviated xattrs that we
* need so that send_xattr_request() can tell the sender about them. */
int xattr_diff(struct file_struct *file, statx *sxp, int find_all)
{
item_list *lst = rsync_xal_l.items;
rsync_xa *snd_rxa, *rec_rxa;
int snd_cnt, rec_cnt;
int cmp, same, xattrs_equal = 1;
if (sxp && XATTR_READY(*sxp)) {
rec_rxa = sxp->xattr->items;
rec_cnt = sxp->xattr->count;
} else {
rec_rxa = NULL;
rec_cnt = 0;
}
if (F_XATTR(file) >= 0)
lst += F_XATTR(file);
else
lst = &empty_xattr;
snd_rxa = lst->items;
snd_cnt = lst->count;
/* If the count of the sender's xattrs is different from our
* (receiver's) xattrs, the lists are not the same. */
if (snd_cnt != rec_cnt) {
if (!find_all)
return 1;
xattrs_equal = 0;
}
while (snd_cnt) {
cmp = rec_cnt ? strcmp(snd_rxa->name, rec_rxa->name) : -1;
if (cmp > 0)
same = 0;
else if (snd_rxa->datum_len > MAX_FULL_DATUM) {
same = cmp == 0 && snd_rxa->datum_len == rec_rxa->datum_len
&& memcmp(snd_rxa->datum + 1, rec_rxa->datum + 1,
MAX_DIGEST_LEN) == 0;
/* Flag unrequested items that we need. */
if (!same && find_all && snd_rxa->datum[0] == XSTATE_ABBREV)
snd_rxa->datum[0] = XSTATE_TODO;
} else {
same = cmp == 0 && snd_rxa->datum_len == rec_rxa->datum_len
&& memcmp(snd_rxa->datum, rec_rxa->datum,
snd_rxa->datum_len) == 0;
}
if (!same) {
if (!find_all)
return 1;
xattrs_equal = 0;
}
if (cmp <= 0) {
snd_rxa++;
snd_cnt--;
}
if (cmp >= 0) {
rec_rxa++;
rec_cnt--;
}
}
if (rec_cnt)
xattrs_equal = 0;
return !xattrs_equal;
}
/* When called by the generator with a NULL fname, this tells the sender
* which abbreviated xattr values we need. When called by the sender
* (with a non-NULL fname), we send all the extra xattr data it needs. */
void send_xattr_request(const char *fname, struct file_struct *file, int f_out)
{
item_list *lst = rsync_xal_l.items;
int j, cnt, prior_req = -1;
rsync_xa *rxa;
lst += F_XATTR(file);
cnt = lst->count;
for (rxa = lst->items, j = 0; j < cnt; rxa++, j++) {
if (rxa->datum_len <= MAX_FULL_DATUM)
continue;
switch (rxa->datum[0]) {
case XSTATE_LOCAL:
/* Items set locally will get cached by receiver. */
rxa->datum[0] = XSTATE_DONE;
continue;
case XSTATE_TODO:
break;
default:
continue;
}
/* Flag that we handled this abbreviated item. */
rxa->datum[0] = XSTATE_DONE;
write_abbrevint(f_out, j - prior_req);
prior_req = j;
if (fname) {
size_t len = 0;
char *ptr;
/* Re-read the long datum. */
if (!(ptr = get_xattr_data(fname, rxa->name, &len, 0)))
continue;
write_abbrevint(f_out, len); /* length might have changed! */
write_buf(f_out, ptr, len);
free(ptr);
}
}
write_byte(f_out, 0); /* end the list */
}
/* Any items set locally by the generator that the receiver doesn't
* get told about get changed back to XSTATE_ABBREV. */
void xattr_clear_locals(struct file_struct *file)
{
item_list *lst = rsync_xal_l.items;
rsync_xa *rxa;
int cnt;
if (F_XATTR(file) < 0)
return;
lst += F_XATTR(file);
cnt = lst->count;
for (rxa = lst->items; cnt--; rxa++) {
if (rxa->datum_len <= MAX_FULL_DATUM)
continue;
if (rxa->datum[0] == XSTATE_LOCAL)
rxa->datum[0] = XSTATE_ABBREV;
}
}
/* When called by the sender, read the request from the generator and mark
* any needed xattrs with a flag that lets us know they need to be sent to
* the receiver. When called by the receiver, reads the sent data and
* stores it in place of its checksum. */
void recv_xattr_request(struct file_struct *file, int f_in)
{
item_list *lst = rsync_xal_l.items;
char *old_datum, *name;
rsync_xa *rxa;
int rel_pos, cnt;
if (F_XATTR(file) < 0) {
rprintf(FERROR, "recv_xattr_request: internal data error!\n");
exit_cleanup(RERR_STREAMIO);
}
lst += F_XATTR(file);
cnt = lst->count;
rxa = lst->items;
rxa -= 1;
while ((rel_pos = read_abbrevint(f_in)) != 0) {
rxa += rel_pos;
cnt -= rel_pos;
if (cnt < 0 || rxa->datum_len <= MAX_FULL_DATUM
|| rxa->datum[0] != XSTATE_ABBREV) {
rprintf(FERROR, "recv_xattr_request: internal abbrev error!\n");
exit_cleanup(RERR_STREAMIO);
}
if (am_sender) {
rxa->datum[0] = XSTATE_TODO;
continue;
}
old_datum = rxa->datum;
rxa->datum_len = read_abbrevint(f_in);
if (rxa->name_len + rxa->datum_len < rxa->name_len)
out_of_memory("recv_xattr_request"); /* overflow */
rxa->datum = new_array(char, rxa->datum_len + rxa->name_len);
if (!rxa->datum)
out_of_memory("recv_xattr_request");
name = rxa->datum + rxa->datum_len;
memcpy(name, rxa->name, rxa->name_len);
rxa->name = name;
free(old_datum);
read_buf(f_in, rxa->datum, rxa->datum_len);
}
}
/* ------------------------------------------------------------------------- */
/* receive and build the rsync_xattr_lists */
void receive_xattr(struct file_struct *file, int f)
{
static item_list temp_xattr = EMPTY_ITEM_LIST;
int count;
int ndx = read_abbrevint(f);
if (ndx < 0 || (size_t)ndx > rsync_xal_l.count) {
rprintf(FERROR, "receive_xattr: xa index %d out of"
" range for %s\n", ndx, f_name(file, NULL));
exit_cleanup(RERR_STREAMIO);
}
if (ndx != 0) {
F_XATTR(file) = ndx - 1;
return;
}
if ((count = read_abbrevint(f)) != 0) {
(void)EXPAND_ITEM_LIST(&temp_xattr, rsync_xa, count);
temp_xattr.count = 0;
}
while (count--) {
char *ptr, *name;
rsync_xa *rxa;
size_t name_len = read_abbrevint(f);
size_t datum_len = read_abbrevint(f);
size_t dget_len = datum_len > MAX_FULL_DATUM ? 1 + MAX_DIGEST_LEN : datum_len;
#ifdef HAVE_LINUX_XATTRS
size_t extra_len = 0;
#else
size_t extra_len = am_root ? RPRE_LEN : 0;
if (dget_len + extra_len < dget_len)
out_of_memory("receive_xattr"); /* overflow */
#endif
if (dget_len + extra_len + name_len < dget_len)
out_of_memory("receive_xattr"); /* overflow */
ptr = new_array(char, dget_len + extra_len + name_len);
if (!ptr)
out_of_memory("receive_xattr");
name = ptr + dget_len + extra_len;
read_buf(f, name, name_len);
if (dget_len == datum_len)
read_buf(f, ptr, dget_len);
else {
*ptr = XSTATE_ABBREV;
read_buf(f, ptr + 1, MAX_DIGEST_LEN);
}
#ifdef HAVE_LINUX_XATTRS
/* Non-root can only save the user namespace. */
if (!am_root && !HAS_PREFIX(name, USER_PREFIX)) {
free(ptr);
continue;
}
#else
/* This OS only has a user namespace, so we either
* strip the user prefix, or we put a non-user
* namespace inside our rsync hierarchy. */
if (HAS_PREFIX(name, USER_PREFIX)) {
name += UPRE_LEN;
name_len -= UPRE_LEN;
} else if (am_root) {
name -= RPRE_LEN;
name_len += RPRE_LEN;
memcpy(name, RSYNC_PREFIX, RPRE_LEN);
} else {
free(ptr);
continue;
}
#endif
rxa = EXPAND_ITEM_LIST(&temp_xattr, rsync_xa, 1);
rxa->name = name;
rxa->datum = ptr;
rxa->name_len = name_len;
rxa->datum_len = datum_len;
}
ndx = rsync_xal_l.count; /* pre-incremented count */
rsync_xal_store(&temp_xattr); /* adds item to rsync_xal_l */
F_XATTR(file) = ndx;
}
/* Turn the xattr data in statx into cached xattr data, setting the index
* values in the file struct. */
void cache_xattr(struct file_struct *file, statx *sxp)
{
int ndx;
if (!sxp->xattr)
return;
ndx = find_matching_xattr(sxp->xattr);
if (ndx < 0)
rsync_xal_store(sxp->xattr); /* adds item to rsync_xal_l */
F_XATTR(file) = ndx;
}
static int rsync_xal_set(const char *fname, item_list *xalp,
const char *fnamecmp, statx *sxp)
{
rsync_xa *rxas = xalp->items;
ssize_t list_len;
size_t i, len;
char *name, *ptr, sum[MAX_DIGEST_LEN];
int name_len, ret = 0;
/* This puts the current name list into the "namebuf" buffer. */
if ((list_len = get_xattr_names(fname)) < 0)
return -1;
for (i = 0; i < xalp->count; i++) {
name = rxas[i].name;
if (XATTR_ABBREV(rxas[i])) {
/* See if the fnamecmp version is identical. */
len = name_len = rxas[i].name_len;
if ((ptr = get_xattr_data(fnamecmp, name, &len, 1)) == NULL) {
still_abbrev:
if (am_generator)
continue;
rprintf(FERROR, "Missing abbreviated xattr value, %s, for %s\n",
rxas[i].name, full_fname(fname));
ret = -1;
continue;
}
if (len != rxas[i].datum_len) {
free(ptr);
goto still_abbrev;
}
sum_init(checksum_seed);
sum_update(ptr, len);
sum_end(sum);
if (memcmp(sum, rxas[i].datum + 1, MAX_DIGEST_LEN) != 0) {
free(ptr);
goto still_abbrev;
}
if (fname == fnamecmp)
; /* Value is already set when identical */
else if (sys_lsetxattr(fname, name, ptr, len) < 0) {
rsyserr(FERROR, errno,
"rsync_xal_set: lsetxattr(\"%s\",\"%s\") failed",
fname, name);
ret = -1;
} else /* make sure caller sets mtime */
sxp->st.st_mtime = (time_t)-1;
if (am_generator) { /* generator items stay abbreviated */
if (rxas[i].datum[0] == XSTATE_ABBREV)
rxas[i].datum[0] = XSTATE_LOCAL;
free(ptr);
continue;
}
memcpy(ptr + len, name, name_len);
free(rxas[i].datum);
rxas[i].name = name = ptr + len;
rxas[i].datum = ptr;
continue;
}
if (sys_lsetxattr(fname, name, rxas[i].datum, rxas[i].datum_len) < 0) {
rsyserr(FERROR, errno,
"rsync_xal_set: lsetxattr(\"%s\",\"%s\") failed",
fname, name);
ret = -1;
} else /* make sure caller sets mtime */
sxp->st.st_mtime = (time_t)-1;
}
/* Remove any extraneous names. */
for (name = namebuf; list_len > 0; name += name_len) {
name_len = strlen(name) + 1;
list_len -= name_len;
#ifdef HAVE_LINUX_XATTRS
/* We always ignore the system namespace, and non-root
* ignores everything but the user namespace. */
if (am_root ? HAS_PREFIX(name, SYSTEM_PREFIX)
: !HAS_PREFIX(name, USER_PREFIX))
continue;
#endif
for (i = 0; i < xalp->count; i++) {
if (strcmp(name, rxas[i].name) == 0)
break;
}
if (i == xalp->count) {
if (sys_lremovexattr(fname, name) < 0) {
rsyserr(FERROR, errno,
"rsync_xal_clear: lremovexattr(\"%s\",\"%s\") failed",
fname, name);
ret = -1;
} else /* make sure caller sets mtime */
sxp->st.st_mtime = (time_t)-1;
}
}
return ret;
}
/* Set extended attributes on indicated filename. */
int set_xattr(const char *fname, const struct file_struct *file,
const char *fnamecmp, statx *sxp)
{
int ndx;
item_list *lst = rsync_xal_l.items;
if (dry_run)
return 1; /* FIXME: --dry-run needs to compute this value */
if (read_only || list_only) {
errno = EROFS;
return -1;
}
ndx = F_XATTR(file);
return rsync_xal_set(fname, lst + ndx, fnamecmp, sxp);
}
#endif /* SUPPORT_XATTRS */