1 /*
2 * CDDL HEADER START
3 *
4 * The contents of this file are subject to the terms of the
5 * Common Development and Distribution License (the "License").
6 * You may not use this file except in compliance with the License.
7 *
8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9 * or http://www.opensolaris.org/os/licensing.
10 * See the License for the specific language governing permissions
11 * and limitations under the License.
12 *
13 * When distributing Covered Code, include this CDDL HEADER in each
14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15 * If applicable, add the following below this CDDL HEADER, with the
16 * fields enclosed by brackets "[]" replaced with your own identifying
17 * information: Portions Copyright [yyyy] [name of copyright owner]
18 *
19 * CDDL HEADER END
20 */
21 /*
22 * Copyright 2009 Sun Microsystems, Inc. All rights reserved.
23 * Use is subject to license terms.
24 */
25
26 /*
27 * This file contains functions for constructing boot arguments
28 * from GRUB menu for Fast Reboot.
29 */
30 #include <stdio.h>
31 #include <stdlib.h>
32 #include <errno.h>
33 #include <strings.h>
34 #include <unistd.h>
35 #include <fcntl.h>
36 #include <assert.h>
37 #include <sys/types.h>
38 #include <sys/elf.h>
39
40 #include "libgrub_impl.h"
41
42 #if defined(__sparc)
43 #define CUR_ELFDATA ELFDATA2MSB
44 #elif defined(__i386)
45 #define CUR_ELFDATA ELFDATA2LSB
46 #endif /* __i386 */
47
48 /*
49 * Open the kernel file.
50 * Return zero on sucess or error code otherwise.
51 * On success the kernel file descriptor is returned in fdp.
52 */
53 static int
get_kernel_fd(const char * path,int * fdp)54 get_kernel_fd(const char *path, int *fdp)
55 {
56 const char *bname;
57 int fd = -1, class, format;
58 char ident[EI_NIDENT];
59
60 /* kernel basename must be unix */
61 if ((bname = strrchr(path, '/')) == NULL)
62 bname = path;
63 else
64 bname++;
65
66 if (strcmp(bname, "unix") != 0) {
67 if (strcmp(bname, "xen.gz") == 0)
68 return (EG_XVMNOTSUP);
69 return (EG_NOTUNIX);
70 }
71
72 if ((fd = open64(path, O_RDONLY)) >= 0 &&
73 (pread64(fd, ident, sizeof (ident), 0) == sizeof (ident))) {
74
75 class = ident[EI_CLASS];
76 format = ident[EI_DATA];
77
78 if ((class == ELFCLASS32 || class == ELFCLASS64) &&
79 (memcmp(&ident[EI_MAG0], ELFMAG, 4) == 0) &&
80 format == CUR_ELFDATA) {
81 *fdp = fd;
82 return (0);
83 }
84 }
85
86 if (fd >= 0)
87 (void) close(fd);
88 return (EG_OPENKERNFILE);
89 }
90
91 /*
92 * Construct boot arguments for Fast Reboot from the ge_barg field of
93 * a GRUB menu entry.
94 * Return 0 on success, errno on failure.
95 */
96 static int
barg2bootargs(const grub_barg_t * barg,grub_boot_args_t * fbarg)97 barg2bootargs(const grub_barg_t *barg, grub_boot_args_t *fbarg)
98 {
99 int rc = 0;
100 char path[BOOTARGS_MAX];
101 char rpath[BOOTARGS_MAX];
102 const grub_fsdesc_t *fsd;
103
104 assert(fbarg);
105 bzero(fbarg, sizeof (*fbarg));
106 fbarg->gba_kernel_fd = -1;
107
108 if (!IS_BARG_VALID(barg))
109 return (EINVAL);
110 if ((fsd = grub_get_rootfsd(&barg->gb_root)) == NULL)
111 return (EG_UNKNOWNFS);
112
113 bcopy(fsd, &fbarg->gba_fsd, sizeof (fbarg->gba_fsd));
114 bcopy(barg->gb_kernel, fbarg->gba_kernel, sizeof (fbarg->gba_kernel));
115 bcopy(barg->gb_module, fbarg->gba_module, sizeof (fbarg->gba_module));
116
117 if (fbarg->gba_fsd.gfs_mountp[0] == 0 &&
118 (rc = grub_fsd_mount_tmp(&fbarg->gba_fsd,
119 barg->gb_root.gr_fstyp)) != 0)
120 return (rc);
121
122 if (snprintf(path, sizeof (path), "%s%s", fbarg->gba_fsd.gfs_mountp,
123 fbarg->gba_kernel) >= sizeof (path)) {
124 rc = E2BIG;
125 goto err_out;
126 }
127 (void) strtok(path, " \t");
128 (void) clean_path(path);
129
130 /*
131 * GRUB requires absolute path, no symlinks, so do we
132 */
133 if ((rc = resolvepath(path, rpath, sizeof (rpath))) == -1)
134 rc = errno;
135 else {
136 rpath[rc] = 0;
137 if (strcmp(rpath, path) != 0)
138 rc = EG_NOTABSPATH;
139 else
140 rc = get_kernel_fd(rpath, &fbarg->gba_kernel_fd);
141 }
142
143 /* construct bootargs command-line */
144 if (rc == 0 && snprintf(fbarg->gba_bootargs,
145 sizeof (fbarg->gba_bootargs), "%s %s", fbarg->gba_fsd.gfs_mountp,
146 fbarg->gba_kernel) >= sizeof (fbarg->gba_bootargs))
147 rc = E2BIG;
148
149 err_out:
150 if (rc != 0)
151 grub_cleanup_boot_args(fbarg);
152
153 return (rc);
154 }
155
156 /*
157 * Construct boot arguments for Fast Reboot from grub_menu_t.
158 * Return 0 on success, errno on failure.
159 */
160 static int
grub_entry_get_boot_args(grub_entry_t * ent,grub_boot_args_t * fbarg)161 grub_entry_get_boot_args(grub_entry_t *ent, grub_boot_args_t *fbarg)
162 {
163 int rc = EG_INVALIDENT;
164
165 if (IS_ENTRY_VALID(ent) && (rc = grub_entry_construct_barg(ent)) == 0)
166 return (barg2bootargs(&ent->ge_barg, fbarg));
167 else
168 return (rc);
169 }
170
171 /*
172 * Construct boot arguments for Fast Reboot from grub_menu_t and the
173 * entry number.
174 * Return 0 on success, errno on failure.
175 */
176 static int
grub_menu_get_boot_args(const grub_menu_t * mp,int num,grub_boot_args_t * fbarg)177 grub_menu_get_boot_args(const grub_menu_t *mp, int num,
178 grub_boot_args_t *fbarg)
179 {
180 grub_entry_t *ent;
181
182 assert(mp);
183 assert(fbarg);
184
185 if ((ent = grub_menu_get_entry(mp, num)) == NULL)
186 return (EG_NOENTRY);
187
188 return (grub_entry_get_boot_args(ent, fbarg));
189 }
190
191 /*
192 * Construct boot arguments from the specified GRUB menu entry.
193 * Caller must allocate space for fbarg, and call grub_cleanup_boot_args()
194 * when it's done with fbarg to clean up.
195 *
196 * Return 0 on success, errno on failure.
197 */
198 int
grub_get_boot_args(grub_boot_args_t * fbarg,const char * menupath,int num)199 grub_get_boot_args(grub_boot_args_t *fbarg, const char *menupath, int num)
200 {
201 int rc;
202 grub_menu_t *mp;
203
204 assert(fbarg);
205 if ((rc = grub_menu_init(menupath, &mp)) == 0) {
206 rc = grub_menu_get_boot_args(mp, num, fbarg);
207 grub_menu_fini(mp);
208 }
209 return (rc);
210 }
211
212 /*
213 * Clean up when done with fbarg: close file handle, unmount file
214 * systems. Must be safe to call even if not all the fields are
215 * set up.
216 */
217 void
grub_cleanup_boot_args(grub_boot_args_t * fbarg)218 grub_cleanup_boot_args(grub_boot_args_t *fbarg)
219 {
220 if (fbarg == NULL)
221 return;
222
223 (void) close(fbarg->gba_kernel_fd);
224 grub_fsd_umount_tmp(&fbarg->gba_fsd);
225 }
226