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-rw-r--r--com32/elflink/ldlinux/setadv.c116
1 files changed, 116 insertions, 0 deletions
diff --git a/com32/elflink/ldlinux/setadv.c b/com32/elflink/ldlinux/setadv.c
new file mode 100644
index 00000000..2e386213
--- /dev/null
+++ b/com32/elflink/ldlinux/setadv.c
@@ -0,0 +1,116 @@
+/* ----------------------------------------------------------------------- *
+ *
+ * Copyright 2007-2008 H. Peter Anvin - All Rights Reserved
+ * Copyright 2009 Intel Corporation; author: H. Peter Anvin
+ *
+ * Permission is hereby granted, free of charge, to any person
+ * obtaining a copy of this software and associated documentation
+ * files (the "Software"), to deal in the Software without
+ * restriction, including without limitation the rights to use,
+ * copy, modify, merge, publish, distribute, sublicense, and/or
+ * sell copies of the Software, and to permit persons to whom
+ * the Software is furnished to do so, subject to the following
+ * conditions:
+ *
+ * The above copyright notice and this permission notice shall
+ * be included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
+ * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
+ * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
+ * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+ * OTHER DEALINGS IN THE SOFTWARE.
+ *
+ * ----------------------------------------------------------------------- */
+
+/*
+ * syslinux/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.
+ *
+ * NOTE: Data is not written to disk unless
+ * syslinux_adv_write() is called.
+ */
+
+#include <syslinux/adv.h>
+#include <klibc/compiler.h>
+#include <inttypes.h>
+#include <string.h>
+#include <errno.h>
+#include <alloca.h>
+
+__export int syslinux_setadv(int tag, size_t size, const void *data)
+{
+ uint8_t *p, *advtmp;
+ size_t rleft, left;
+
+ 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;
+ }
+
+ rleft = left = syslinux_adv_size();
+ p = advtmp = alloca(left);
+ memcpy(p, syslinux_adv_ptr(), left); /* Make working copy */
+
+ while (rleft >= 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 >= rleft) {
+ /* Entire remainder is our tag */
+ break;
+ }
+ memmove(p, p + plen, rleft - plen);
+ rleft -= plen; /* Fewer bytes to read, but not to write */
+ } else {
+ /* Not our tag */
+ if (plen > rleft)
+ break; /* Corrupt tag (overrun) - overwrite it */
+
+ left -= plen;
+ rleft -= 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 to low memory */
+ memcpy(syslinux_adv_ptr(), advtmp, syslinux_adv_size());
+
+ return 0;
+}