ostree/src/libostree/ostree-core.c

272 lines
7.1 KiB
C

/* -*- mode: C; c-file-style: "gnu"; indent-tabs-mode: nil; -*-
*
* Copyright (C) 2011 Colin Walters <walters@verbum.org>
*
* 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 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, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*
* Author: Colin Walters <walters@verbum.org>
*/
#include "config.h"
#include "ostree.h"
#include "otutil.h"
#include <sys/types.h>
#include <attr/xattr.h>
static char *
stat_to_string (struct stat *stbuf)
{
return g_strdup_printf ("%u:%u:%u",
(guint32)(stbuf->st_mode & ~S_IFMT),
(guint32)stbuf->st_uid,
(guint32)stbuf->st_gid);
}
static char *
canonicalize_xattrs (char *xattr_string, size_t len)
{
char *p;
GSList *xattrs = NULL;
GSList *iter;
GString *result;
result = g_string_new (0);
p = xattr_string;
while (p < xattr_string+len)
{
xattrs = g_slist_prepend (xattrs, p);
p += strlen (p) + 1;
}
xattrs = g_slist_sort (xattrs, (GCompareFunc) strcmp);
for (iter = xattrs; iter; iter = iter->next)
g_string_append (result, iter->data);
g_slist_free (xattrs);
return g_string_free (result, FALSE);
}
static gboolean
read_xattr_name_array (const char *path,
const char *xattrs,
size_t len,
GVariantBuilder *builder,
GError **error)
{
gboolean ret = FALSE;
const char *p;
p = xattrs;
while (p < xattrs+len)
{
ssize_t bytes_read;
char *buf;
bytes_read = lgetxattr (path, p, NULL, 0);
if (bytes_read < 0)
{
ot_util_set_error_from_errno (error, errno);
goto out;
}
if (bytes_read == 0)
continue;
buf = g_malloc (bytes_read);
if (lgetxattr (path, p, buf, bytes_read) < 0)
{
ot_util_set_error_from_errno (error, errno);
g_free (buf);
goto out;
}
g_variant_builder_add (builder, "(@ay@ay)",
g_variant_new_bytestring (p),
g_variant_new_from_data (G_VARIANT_TYPE ("ay"),
buf, bytes_read, FALSE, g_free, buf));
p = p + strlen (p) + 1;
}
ret = TRUE;
out:
return ret;
}
GVariant *
ostree_get_xattrs_for_path (const char *path,
GError **error)
{
GVariant *ret = NULL;
GVariantBuilder builder;
char *xattr_names = NULL;
char *xattr_names_canonical = NULL;
ssize_t bytes_read;
g_variant_builder_init (&builder, G_VARIANT_TYPE ("a(ayay)"));
bytes_read = llistxattr (path, NULL, 0);
if (bytes_read < 0)
{
if (errno != ENOTSUP)
{
ot_util_set_error_from_errno (error, errno);
goto out;
}
}
else if (bytes_read > 0)
{
xattr_names = g_malloc (bytes_read);
if (llistxattr (path, xattr_names, bytes_read) < 0)
{
ot_util_set_error_from_errno (error, errno);
goto out;
}
xattr_names_canonical = canonicalize_xattrs (xattr_names, bytes_read);
if (!read_xattr_name_array (path, xattr_names_canonical, bytes_read, &builder, error))
goto out;
}
ret = g_variant_builder_end (&builder);
out:
if (!ret)
g_variant_builder_clear (&builder);
g_free (xattr_names);
g_free (xattr_names_canonical);
return ret;
}
gboolean
ostree_stat_and_checksum_file (int dir_fd, const char *path,
GChecksum **out_checksum,
struct stat *out_stbuf,
GError **error)
{
GChecksum *content_sha256 = NULL;
GChecksum *content_and_meta_sha256 = NULL;
char *stat_string = NULL;
ssize_t bytes_read;
GVariant *xattrs = NULL;
int fd = -1;
DIR *temp_dir = NULL;
char *basename = NULL;
gboolean ret = FALSE;
char *symlink_target = NULL;
char *device_id = NULL;
struct stat stbuf;
basename = g_path_get_basename (path);
if (dir_fd == -1)
{
char *dirname = g_path_get_dirname (path);
temp_dir = opendir (dirname);
if (temp_dir == NULL)
{
ot_util_set_error_from_errno (error, errno);
g_free (dirname);
}
g_free (dirname);
dir_fd = dirfd (temp_dir);
}
if (fstatat (dir_fd, basename, &stbuf, AT_SYMLINK_NOFOLLOW) < 0)
{
ot_util_set_error_from_errno (error, errno);
goto out;
}
if (S_ISREG(stbuf.st_mode))
{
fd = ot_util_open_file_read_at (dir_fd, basename, error);
if (fd < 0)
{
ot_util_set_error_from_errno (error, errno);
goto out;
}
}
stat_string = stat_to_string (&stbuf);
xattrs = ostree_get_xattrs_for_path (path, error);
if (!xattrs)
goto out;
content_sha256 = g_checksum_new (G_CHECKSUM_SHA256);
if (S_ISREG(stbuf.st_mode))
{
guint8 buf[8192];
while ((bytes_read = read (fd, buf, sizeof (buf))) > 0)
g_checksum_update (content_sha256, buf, bytes_read);
if (bytes_read < 0)
{
ot_util_set_error_from_errno (error, errno);
goto out;
}
}
else if (S_ISLNK(stbuf.st_mode))
{
symlink_target = g_malloc (PATH_MAX);
if (readlinkat (dir_fd, basename, symlink_target, PATH_MAX) < 0)
{
ot_util_set_error_from_errno (error, errno);
goto out;
}
g_checksum_update (content_sha256, (guint8*)symlink_target, strlen (symlink_target));
}
else if (S_ISCHR(stbuf.st_mode) || S_ISBLK(stbuf.st_mode))
{
device_id = g_strdup_printf ("%u", (guint)stbuf.st_rdev);
g_checksum_update (content_sha256, (guint8*)device_id, strlen (device_id));
}
else
{
g_set_error (error, G_IO_ERROR,
G_IO_ERROR_FAILED,
"Unsupported file '%s' (must be regular, symbolic link, or device)",
path);
goto out;
}
content_and_meta_sha256 = g_checksum_copy (content_sha256);
g_checksum_update (content_and_meta_sha256, (guint8*)stat_string, strlen (stat_string));
g_checksum_update (content_and_meta_sha256, (guint8*)g_variant_get_data (xattrs), g_variant_get_size (xattrs));
*out_stbuf = stbuf;
*out_checksum = content_and_meta_sha256;
ret = TRUE;
out:
if (fd >= 0)
close (fd);
if (temp_dir != NULL)
closedir (temp_dir);
g_free (symlink_target);
g_free (basename);
g_free (stat_string);
if (xattrs)
g_variant_unref (xattrs);
if (content_sha256)
g_checksum_free (content_sha256);
return ret;
}