1 /* ----------------------------------------------------------------------- *
3 * Copyright 2007-2008 H. Peter Anvin - All Rights Reserved
4 * Copyright 2010 Intel Corporation; author: H. Peter Anvin
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, Inc., 53 Temple Place Ste 330,
9 * Boston MA 02111-1307, USA; either version 2 of the License, or
10 * (at your option) any later version; incorporated herein by reference.
12 * ----------------------------------------------------------------------- */
19 * Return 0 on success, -1 on error, and set errno.
33 #include <sys/types.h>
38 * Read the ADV from an existing instance, or initialize if invalid.
39 * Returns -1 on fatal errors, 0 if ADV is okay, 1 if the ADV is
40 * invalid, and 2 if the file does not exist.
42 int read_adv(const char *path, const char *cfg)
50 rv = asprintf(&file, "%s%s%s", path,
51 path[0] && path[strlen(path) - 1] == '/' ? "" : "/", cfg);
53 if (rv < 0 || !file) {
58 fd = open(file, O_RDONLY);
60 if (errno != ENOENT) {
63 syslinux_reset_adv(syslinux_adv);
64 err = 2; /* Nonexistence is not a fatal error */
66 } else if (fstat(fd, &st)) {
68 } else if (st.st_size < 2 * ADV_SIZE) {
69 /* Too small to be useful */
70 syslinux_reset_adv(syslinux_adv);
71 err = 0; /* Nothing to read... */
72 } else if (xpread(fd, syslinux_adv, 2 * ADV_SIZE,
73 st.st_size - 2 * ADV_SIZE) != 2 * ADV_SIZE) {
76 /* We got it... maybe? */
77 err = syslinux_validate_adv(syslinux_adv) ? 1 : 0;
92 * Update the ADV in an existing installation.
94 int write_adv(const char *path, const char *cfg)
96 unsigned char advtmp[2 * ADV_SIZE];
103 rv = asprintf(&file, "%s%s%s", path,
104 path[0] && path[strlen(path) - 1] == '/' ? "" : "/", cfg);
106 if (rv < 0 || !file) {
111 fd = open(file, O_RDONLY);
114 } else if (fstat(fd, &st)) {
116 } else if (st.st_size < 2 * ADV_SIZE) {
117 /* Too small to be useful */
119 } else if (xpread(fd, advtmp, 2 * ADV_SIZE,
120 st.st_size - 2 * ADV_SIZE) != 2 * ADV_SIZE) {
123 /* We got it... maybe? */
124 err = syslinux_validate_adv(advtmp) ? -2 : 0;
126 /* Got a good one, write our own ADV here */
127 clear_attributes(fd);
129 /* Need to re-open read-write */
131 fd = open(file, O_RDWR | O_SYNC);
134 } else if (fstat(fd, &xst) || xst.st_ino != st.st_ino ||
135 xst.st_dev != st.st_dev || xst.st_size != st.st_size) {
136 fprintf(stderr, "%s: race condition on write\n", file);
139 /* Write our own version ... */
140 if (xpwrite(fd, syslinux_adv, 2 * ADV_SIZE,
141 st.st_size - 2 * ADV_SIZE) != 2 * ADV_SIZE) {
151 fprintf(stderr, "%s: cannot write auxilliary data (need --update)?\n",