Squashed 'third_party/elfutils/' content from commit 555e15e
Change-Id: I61cde98949e47e5c8c09c33260de17f30921be79
git-subtree-dir: third_party/elfutils
git-subtree-split: 555e15ebe8bf1eb33d00747173cfc80cc65648a4
diff --git a/lib/crc32_file.c b/lib/crc32_file.c
new file mode 100644
index 0000000..f7607d0
--- /dev/null
+++ b/lib/crc32_file.c
@@ -0,0 +1,92 @@
+/* Compute CRC32 checksum of file contents.
+ Copyright (C) 2006 Red Hat, Inc.
+ This file is part of elfutils.
+
+ This file is free software; you can redistribute it and/or modify
+ it under the terms of either
+
+ * the GNU Lesser General Public License as published by the Free
+ Software Foundation; either version 3 of the License, or (at
+ your option) any later version
+
+ or
+
+ * the GNU General Public License as published by the Free
+ Software Foundation; either version 2 of the License, or (at
+ your option) any later version
+
+ or both in parallel, as here.
+
+ elfutils is distributed in the hope that it will be useful, but
+ WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ General Public License for more details.
+
+ You should have received copies of the GNU General Public License and
+ the GNU Lesser General Public License along with this program. If
+ not, see <http://www.gnu.org/licenses/>. */
+
+#ifdef HAVE_CONFIG_H
+# include <config.h>
+#endif
+
+#include "libeu.h"
+#include <errno.h>
+#include <unistd.h>
+#include <sys/stat.h>
+#include <sys/mman.h>
+#include "system.h"
+
+int
+crc32_file (int fd, uint32_t *resp)
+{
+ unsigned char buffer[1024 * 8];
+ uint32_t crc = 0;
+ off_t off = 0;
+ ssize_t count;
+
+ struct stat st;
+ if (fstat (fd, &st) == 0)
+ {
+ /* Try mapping in the file data. */
+ size_t mapsize = st.st_size;
+ void *mapped = mmap (NULL, mapsize, PROT_READ, MAP_PRIVATE, fd, 0);
+ if (mapped == MAP_FAILED && errno == ENOMEM)
+ {
+ const size_t pagesize = sysconf (_SC_PAGESIZE);
+ mapsize = ((mapsize / 2) + pagesize - 1) & -pagesize;
+ while (mapsize >= pagesize
+ && (mapped = mmap (NULL, mapsize, PROT_READ, MAP_PRIVATE,
+ fd, 0)) == MAP_FAILED && errno == ENOMEM)
+ mapsize /= 2;
+ }
+ if (mapped != MAP_FAILED)
+ {
+ do
+ {
+ if (st.st_size <= (off_t) mapsize)
+ {
+ *resp = crc32 (crc, mapped, st.st_size);
+ munmap (mapped, mapsize);
+ return 0;
+ }
+ crc = crc32 (crc, mapped, mapsize);
+ off += mapsize;
+ st.st_size -= mapsize;
+ } while (mmap (mapped, mapsize, PROT_READ, MAP_FIXED|MAP_PRIVATE,
+ fd, off) == mapped);
+ munmap (mapped, mapsize);
+ }
+ }
+
+ while ((count = TEMP_FAILURE_RETRY (pread (fd, buffer, sizeof buffer,
+ off))) > 0)
+ {
+ off += count;
+ crc = crc32 (crc, buffer, count);
+ }
+
+ *resp = crc;
+
+ return count == 0 ? 0 : -1;
+}