librazor/root.c
author J. Ali Harlow <ali@juiblex.co.uk>
Thu Feb 16 17:33:47 2012 +0000 (2012-02-16)
changeset 424 8cbc438cc298
parent 406 5ab137def3d1
child 425 0c8bdd8dc942
permissions -rw-r--r--
Allow multiple atomic transactions to be used with one root object.
This allows transactions that include barriers to be performed
while holding an exclusive system lock.
     1 /*
     2  * Copyright (C) 2008  Kristian Høgsberg <krh@redhat.com>
     3  * Copyright (C) 2008  Red Hat, Inc
     4  * Copyright (C) 2009, 2011, 2012  J. Ali Harlow <ali@juiblex.co.uk>
     5  *
     6  * This program is free software; you can redistribute it and/or modify
     7  * it under the terms of the GNU General Public License as published by
     8  * the Free Software Foundation; either version 2 of the License, or
     9  * (at your option) any later version.
    10  *
    11  * This program is distributed in the hope that it will be useful,
    12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
    13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    14  * GNU General Public License for more details.
    15  *
    16  * You should have received a copy of the GNU General Public License along
    17  * with this program; if not, write to the Free Software Foundation, Inc.,
    18  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
    19  */
    20 
    21 #include "config.h"
    22 
    23 #include <stdlib.h>
    24 #include <stdint.h>
    25 #include <stdio.h>
    26 #include <string.h>
    27 #include <sys/stat.h>
    28 #include <dirent.h>
    29 #include <unistd.h>
    30 #include <fcntl.h>
    31 #include <limits.h>
    32 #include <assert.h>
    33 #ifdef MSWIN_API
    34 #include <shlobj.h>
    35 #endif
    36 
    37 #include "razor.h"
    38 #include "razor-internal.h"
    39 
    40 #ifndef O_BINARY
    41 #define O_BINARY	0
    42 #endif
    43 
    44 static const char system_repo_filename[] = "system.rzdb";
    45 /*
    46  * system_lock_filename is chosen to be the same as the pre v0.3
    47  * next_repo_filename. This means that once a system has been
    48  * updated by a v0.3+ copy of razor all pre v0.3 versions of razor
    49  * will see the system as permenantly locked.
    50  */
    51 static const char system_lock_filename[] = "system-next.rzdb";
    52 #ifdef MSWIN_API
    53 #define RAZOR_ROOT_PATH	NULL
    54 #else
    55 #define RAZOR_ROOT_PATH	"/var/lib/razor"
    56 #endif
    57 static const char *razor_root_path = RAZOR_ROOT_PATH;
    58 
    59 struct razor_root {
    60 	struct razor_set *system;
    61 	char *path;
    62 };
    63 
    64 static void
    65 razor_root_init(void)
    66 {
    67 #ifdef MSWIN_API
    68 	static char root_path[MAX_PATH];
    69 	if (!razor_root_path) {
    70 		SHGetFolderPath(NULL,
    71 			CSIDL_COMMON_APPDATA | CSIDL_FLAG_DONT_VERIFY, NULL, 0,
    72 			root_path);
    73 		strcat(root_path, "\\Razor");
    74 		razor_root_path = root_path;
    75 	}
    76 #endif
    77 }
    78 
    79 RAZOR_EXPORT int
    80 razor_root_create(const char *root)
    81 {
    82 	int retval;
    83 	struct stat buf;
    84 	struct razor_set *set;
    85 	struct razor_atomic *atomic;
    86 	char *file, *path;
    87 
    88 	assert (root != NULL);
    89 
    90 	razor_root_init();
    91 	if (root[0] == '\0') {
    92 		/* root is file system root */
    93 	} else if (stat(root, &buf) < 0) {
    94 		if (mkdir(root, 0777) < 0) {
    95 			fprintf(stderr,
    96 				"could not create install root \"%s\"\n",
    97 				root);
    98 			return -1;
    99 		}
   100 		fprintf(stderr, "created install root \"%s\"\n", root);
   101 	} else if (!S_ISDIR(buf.st_mode)) {
   102 		fprintf(stderr,
   103 			"install root \"%s\" exists, but is not a directory\n",
   104 			root);
   105 		return -1;
   106 	}
   107 
   108 	file = razor_concat(razor_root_path, "/", system_repo_filename, NULL);
   109 	path = razor_concat(root, file, NULL);
   110 	retval = !stat(path, &buf);
   111 	if (retval) {
   112 		fprintf(stderr,
   113 			"a razor install root is already initialized\n");
   114 		free(path);
   115 		free(file);
   116 		return retval;
   117 	}
   118 
   119 	atomic = razor_atomic_open("Create initial package set");
   120 	razor_atomic_make_dirs(atomic, root, file);
   121 	set = razor_set_create();
   122 	razor_set_write(set, atomic, path, RAZOR_SECTION_ALL);
   123 	free(path);
   124 	free(file);
   125 	retval = razor_atomic_commit(atomic);
   126 	if (retval)
   127 		fprintf(stderr, "could not write initial package set\n");
   128 	razor_set_unref(set);
   129 	razor_atomic_destroy(atomic);
   130 
   131 	return retval;
   132 }
   133 
   134 RAZOR_EXPORT struct razor_root *
   135 razor_root_open(const char *root, struct razor_error **error)
   136 {
   137 	struct razor_root *image;
   138 	char *lock_path;
   139 	int r;
   140 
   141 	assert (root != NULL);
   142 
   143 	razor_root_init();
   144 	image = malloc(sizeof *image);
   145 	if (image == NULL) {
   146 		razor_set_error(error, NULL, "Not enough memory");
   147 		return NULL;
   148 	}
   149 
   150 	image->system = razor_set_create_without_root();
   151 	if (image->system == NULL) {
   152 		free(image);
   153 		razor_set_error(error, NULL, "Not enough memory");
   154 		return NULL;
   155 	}
   156 
   157 	lock_path = razor_concat(root, razor_root_path, "/",
   158 				 system_lock_filename, NULL);
   159 
   160 	r = razor_set_aquire_lock(image->system, lock_path, 1);
   161 
   162 	free(lock_path);
   163 
   164 	if (r < 0) {
   165 		razor_set_error(error, NULL,
   166 				"Failed to aquire exclusive system lock");
   167 		razor_set_unref(image->system);
   168 		free(image);
   169 		return NULL;
   170 	}
   171 
   172 	image->path = razor_concat(root, razor_root_path, "/",
   173 				   system_repo_filename, NULL);
   174 
   175 	if (razor_set_bind_sections(image->system, image->path,
   176 				    RAZOR_SET_PRIVATE, error)) {
   177 		free(image->path);
   178 		razor_set_unref(image->system);
   179 		free(image);
   180 		return NULL;
   181 	}
   182 
   183 	return image;
   184 }
   185 
   186 RAZOR_EXPORT struct razor_set *
   187 razor_root_open_read_only(const char *root, struct razor_error **error)
   188 {
   189 	char *path;
   190 	struct razor_set *set;
   191 
   192 	assert (root != NULL);
   193 
   194 	razor_root_init();
   195 	set = razor_set_create_without_root();
   196 	if (set == NULL) {
   197 		razor_set_error(error, NULL, "Not enough memory");
   198 		return NULL;
   199 	}
   200 
   201 	path = razor_concat(root, razor_root_path, "/", system_lock_filename,
   202 			    NULL);
   203 	if (razor_set_aquire_lock(set, path, 0) < 0) {
   204 		razor_set_error(error, NULL,
   205 				"Failed to aquire non-exclusive system lock");
   206 		free(path);
   207 		razor_set_unref(set);
   208 		return NULL;
   209 	}
   210 
   211 	free(path);
   212 	path = razor_concat(root, razor_root_path, "/", system_repo_filename,
   213 			    NULL);
   214 
   215 	if (razor_set_bind_sections(set, path, 0, error)) {
   216 		razor_set_unref(set);
   217 		set = NULL;
   218 	}
   219 
   220 	free(path);
   221 
   222 	return set;
   223 }
   224 
   225 RAZOR_EXPORT struct razor_set *
   226 razor_root_get_system_set(struct razor_root *root)
   227 {
   228 	assert (root != NULL);
   229 
   230 	return root->system;
   231 }
   232 
   233 RAZOR_EXPORT int
   234 razor_root_close(struct razor_root *root)
   235 {
   236 	assert (root != NULL);
   237 
   238 	razor_set_unref(root->system);
   239 	free(root->path);
   240 	free(root);
   241 
   242 	return 0;
   243 }
   244 
   245 RAZOR_EXPORT int
   246 razor_root_update(struct razor_root *root, struct razor_set *next,
   247 		  struct razor_atomic *atomic)
   248 {
   249 	int handle, retval;
   250 
   251 	assert (root != NULL);
   252 	assert (next != NULL);
   253 
   254 	handle = razor_atomic_create_file(atomic, root->path,
   255 					  S_IRWXU | S_IRWXG | S_IRWXO);
   256 	if (handle < 0)
   257 		return handle;
   258 
   259 	razor_set_write_to_handle(next, atomic, handle, RAZOR_SECTION_ALL);
   260 
   261 	retval = razor_atomic_close(atomic, handle);
   262 
   263 	if (!retval) {
   264 		razor_set_unref(root->system);
   265 		root->system = razor_set_ref(next);
   266 	}
   267 
   268 	return retval;
   269 }