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-rw-r--r--ext/libelf/libelf_checksum.c96
1 files changed, 96 insertions, 0 deletions
diff --git a/ext/libelf/libelf_checksum.c b/ext/libelf/libelf_checksum.c
new file mode 100644
index 000000000..143517592
--- /dev/null
+++ b/ext/libelf/libelf_checksum.c
@@ -0,0 +1,96 @@
+/*-
+ * Copyright (c) 2006 Joseph Koshy
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include "gelf.h"
+
+#include "_libelf.h"
+
+static unsigned long
+_libelf_sum(unsigned long c, const unsigned char *s, size_t size)
+{
+ if (s == NULL || size == 0)
+ return (c);
+
+ while (size--)
+ c += *s++;
+
+ return (c);
+}
+
+unsigned long
+_libelf_checksum(Elf *e, int elfclass)
+{
+ size_t shn;
+ Elf_Scn *scn;
+ Elf_Data *d;
+ unsigned long checksum;
+ GElf_Ehdr eh;
+ GElf_Shdr shdr;
+
+ if (e == NULL) {
+ LIBELF_SET_ERROR(ARGUMENT, 0);
+ return (0L);
+ }
+
+ if (e->e_class != elfclass) {
+ LIBELF_SET_ERROR(CLASS, 0);
+ return (0L);
+ }
+
+ if (gelf_getehdr(e, &eh) == NULL)
+ return (0);
+
+ /*
+ * Iterate over all sections in the ELF file, computing the
+ * checksum along the way.
+ *
+ * The first section is always SHN_UNDEF and can be skipped.
+ * Non-allocatable sections are skipped, as are sections that
+ * could be affected by utilities such as strip(1).
+ */
+
+ checksum = 0;
+ for (shn = 1; shn < e->e_u.e_elf.e_nscn; shn++) {
+ if ((scn = elf_getscn(e, shn)) == NULL)
+ return (0);
+ if (gelf_getshdr(scn, &shdr) == NULL)
+ return (0);
+ if ((shdr.sh_flags & SHF_ALLOC) == 0 ||
+ shdr.sh_type == SHT_DYNAMIC ||
+ shdr.sh_type == SHT_DYNSYM)
+ continue;
+
+ d = NULL;
+ while ((d = elf_rawdata(scn, d)) != NULL)
+ checksum = _libelf_sum(checksum,
+ (unsigned char *) d->d_buf, d->d_size);
+ }
+
+ /*
+ * Return a 16-bit checksum compatible with Solaris.
+ */
+ return (((checksum >> 16) & 0xFFFFUL) + (checksum & 0xFFFFUL));
+}