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));
+}