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l---------libinstaller/advconst.h1
-rw-r--r--libinstaller/setadv.c160
-rw-r--r--libinstaller/syslxint.h74
3 files changed, 235 insertions, 0 deletions
diff --git a/libinstaller/advconst.h b/libinstaller/advconst.h
new file mode 120000
index 00000000..044572ba
--- /dev/null
+++ b/libinstaller/advconst.h
@@ -0,0 +1 @@
+../com32/include/syslinux/advconst.h \ No newline at end of file
diff --git a/libinstaller/setadv.c b/libinstaller/setadv.c
new file mode 100644
index 00000000..e786e401
--- /dev/null
+++ b/libinstaller/setadv.c
@@ -0,0 +1,160 @@
+/* ----------------------------------------------------------------------- *
+ *
+ * Copyright 2007 H. Peter Anvin - All Rights Reserved
+ *
+ * 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, Inc., 53 Temple Place Ste 330,
+ * Boston MA 02111-1307, USA; either version 2 of the License, or
+ * (at your option) any later version; incorporated herein by reference.
+ *
+ * ----------------------------------------------------------------------- */
+
+/*
+ * setadv.c
+ *
+ * (Over)write a data item in the auxilliary data vector. To
+ * delete an item, set its length to zero.
+ *
+ * Return 0 on success, -1 on error, and set errno.
+ *
+ */
+
+#include <string.h>
+#include <errno.h>
+#include "syslxint.h"
+
+unsigned char syslinux_adv[2*ADV_SIZE];
+
+#define ADV_MAGIC1 0x5a2d2fa5 /* Head signature */
+#define ADV_MAGIC2 0xa3041767 /* Total checksum */
+#define ADV_MAGIC3 0xdd28bf64 /* Tail signature */
+
+static void cleanup_adv(unsigned char *advbuf)
+{
+ int i;
+ uint32_t csum;
+
+ /* Make sure both copies agree, and update the checksum */
+ set_32(advbuf, ADV_MAGIC1);
+
+ csum = ADV_MAGIC2;
+ for (i = 8; i < ADV_SIZE-4; i += 4)
+ csum -= get_32(advbuf+i);
+
+ set_32(advbuf+4, csum);
+ set_32(advbuf+ADV_SIZE-4, ADV_MAGIC3);
+
+ memcpy(advbuf+ADV_SIZE, advbuf, ADV_SIZE);
+}
+
+int syslinux_setadv(int tag, size_t size, const void *data)
+{
+ uint8_t *p;
+ size_t left;
+ uint8_t advtmp[ADV_SIZE];
+
+ if ((unsigned)tag-1 > 254) {
+ errno = EINVAL;
+ return -1; /* Impossible tag value */
+ }
+
+ if (size > 255) {
+ errno = ENOSPC; /* Max 255 bytes for a data item */
+ return -1;
+ }
+
+ left = ADV_LEN;
+ p = advtmp;
+ memcpy(p, syslinux_adv+2*4, left); /* Make working copy */
+
+ while (left >= 2) {
+ uint8_t ptag = p[0];
+ size_t plen = p[1]+2;
+
+ if (ptag == ADV_END)
+ break;
+
+ if (ptag == tag) {
+ /* Found our tag. Delete it. */
+
+ if (plen >= left) {
+ /* Entire remainder is our tag */
+ break;
+ }
+ memmove(p, p+plen, left-plen);
+ } else {
+ /* Not our tag */
+ if (plen > left)
+ break; /* Corrupt tag (overrun) - overwrite it */
+
+ left -= plen;
+ p += plen;
+ }
+ }
+
+ /* Now (p, left) reflects the position to write in and how much space
+ we have for our data. */
+
+ if (size) {
+ if (left < size+2) {
+ errno = ENOSPC; /* Not enough space for data */
+ return -1;
+ }
+
+ *p++ = tag;
+ *p++ = size;
+ memcpy(p, data, size);
+ p += size;
+ left -= size+2;
+ }
+
+ memset(p, 0, left);
+
+ /* If we got here, everything went OK, commit the write */
+ memcpy(syslinux_adv+2*4, advtmp, ADV_LEN);
+ cleanup_adv(syslinux_adv);
+
+ return 0;
+}
+
+void syslinux_reset_adv(unsigned char *advbuf)
+{
+ /* Create an all-zero ADV */
+ memset(advbuf+2*4, 0, ADV_LEN);
+ cleanup_adv(advbuf);
+}
+
+static int adv_consistent(const unsigned char *p)
+{
+ int i;
+ uint32_t csum;
+
+ if (get_32(p) != ADV_MAGIC1 || get_32(p+ADV_SIZE-4) != ADV_MAGIC3)
+ return 0;
+
+ csum = 0;
+ for (i = 4; i < ADV_SIZE-4; i += 4)
+ csum += get_32(p+i);
+
+ return csum == ADV_MAGIC2;
+}
+
+/*
+ * Verify that an in-memory ADV is consistent, making the copies consistent.
+ * If neither copy is OK, return -1 and call syslinux_reset_adv().
+ */
+int syslinux_validate_adv(unsigned char *advbuf)
+{
+ if (adv_consistent(advbuf+0*ADV_SIZE)) {
+ memcpy(advbuf+ADV_SIZE, advbuf, ADV_SIZE);
+ return 0;
+ } else if (adv_consistent(advbuf+1*ADV_SIZE)) {
+ memcpy(advbuf, advbuf+ADV_SIZE, ADV_SIZE);
+ return 0;
+ } else {
+ syslinux_reset_adv(advbuf);
+ return -1;
+ }
+}
+
diff --git a/libinstaller/syslxint.h b/libinstaller/syslxint.h
new file mode 100644
index 00000000..e296df1d
--- /dev/null
+++ b/libinstaller/syslxint.h
@@ -0,0 +1,74 @@
+/* ----------------------------------------------------------------------- *
+ *
+ * Copyright 2007 H. Peter Anvin - All Rights Reserved
+ *
+ * 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, Inc., 53 Temple Place Ste 330,
+ * Boston MA 02111-1307, USA; either version 2 of the License, or
+ * (at your option) any later version; incorporated herein by reference.
+ *
+ * ----------------------------------------------------------------------- */
+
+#ifndef SYSLXINT_H
+#define SYSLXINT_H
+
+#include "syslinux.h"
+
+/*
+ * Access functions for littleendian numbers, possibly misaligned.
+ */
+static inline uint8_t get_8(const unsigned char *p)
+{
+ return *(const uint8_t *)p;
+}
+
+static inline uint16_t get_16(const unsigned char *p)
+{
+#if defined(__i386__) || defined(__x86_64__)
+ /* Littleendian and unaligned-capable */
+ return *(const uint16_t *)p;
+#else
+ return (uint16_t)p[0] + ((uint16_t)p[1] << 8);
+#endif
+}
+
+static inline uint32_t get_32(const unsigned char *p)
+{
+#if defined(__i386__) || defined(__x86_64__)
+ /* Littleendian and unaligned-capable */
+ return *(const uint32_t *)p;
+#else
+ return (uint32_t)p[0] + ((uint32_t)p[1] << 8) +
+ ((uint32_t)p[2] << 16) + ((uint32_t)p[3] << 24);
+#endif
+}
+
+static inline void set_16(unsigned char *p, uint16_t v)
+{
+#if defined(__i386__) || defined(__x86_64__)
+ /* Littleendian and unaligned-capable */
+ *(uint16_t *)p = v;
+#else
+ p[0] = (v & 0xff);
+ p[1] = ((v >> 8) & 0xff);
+#endif
+}
+
+static inline void set_32(unsigned char *p, uint32_t v)
+{
+#if defined(__i386__) || defined(__x86_64__)
+ /* Littleendian and unaligned-capable */
+ *(uint32_t *)p = v;
+#else
+ p[0] = (v & 0xff);
+ p[1] = ((v >> 8) & 0xff);
+ p[2] = ((v >> 16) & 0xff);
+ p[3] = ((v >> 24) & 0xff);
+#endif
+}
+
+#define SECTOR_SHIFT 9 /* 512-byte sectors */
+#define SECTOR_SIZE (1 << SECTOR_SHIFT)
+
+#endif /* SYSLXINT_H */