Add md5 command to toolbox.

This command outputs the MD5 for specified files.  The output is
in the same form as the md5sum command on Linux.

Change-Id: Ie0e6faf678469ac886bba8b46d98c0e54976a1ed
Signed-off-by: Scott Anderson <saa@google.com>

toolbox/Android.mk

@@ -55,7 +55,8 @@ TOOLS := \
 	nandread \
 	ionice \
 	touch \
-	lsof
+	lsof \
+	md5
 
 ifneq (,$(filter userdebug eng,$(TARGET_BUILD_VARIANT)))
 TOOLS += r
@@ -68,6 +69,8 @@ LOCAL_SRC_FILES:= \
 
 LOCAL_SHARED_LIBRARIES := libcutils libc libusbhost
 
+LOCAL_C_INCLUDES := bionic/libc/bionic
+
 LOCAL_MODULE:= toolbox
 
 # Including this will define $(intermediates).

toolbox/md5.c

@@ -0,0 +1,77 @@
+#include <errno.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <unistd.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <md5.h>
+
+/* When this was written, bionic's md5.h did not define this. */
+#ifndef MD5_DIGEST_LENGTH
+#define MD5_DIGEST_LENGTH 16
+#endif
+
+static int usage()
+{
+    fprintf(stderr,"md5 file ...\n");
+    return -1;
+}
+
+static int do_md5(const char *path)
+{
+    unsigned int i;
+    int fd;
+    MD5_CTX md5_ctx;
+    unsigned char md5[MD5_DIGEST_LENGTH];
+
+    fd = open(path, O_RDONLY);
+    if (fd < 0) {
+        fprintf(stderr,"could not open %s, %s\n", path, strerror(errno));
+        return -1;
+    }
+
+    /* Note that bionic's MD5_* functions return void. */
+    MD5_Init(&md5_ctx);
+
+    while (1) {
+        char buf[4096];
+        ssize_t rlen;
+        rlen = read(fd, buf, sizeof(buf));
+        if (rlen == 0)
+            break;
+        else if (rlen < 0) {
+            (void)close(fd);
+            fprintf(stderr,"could not read %s, %s\n", path, strerror(errno));
+            return -1;
+        }
+        MD5_Update(&md5_ctx, buf, rlen);
+    }
+    if (close(fd)) {
+        fprintf(stderr,"could not close %s, %s\n", path, strerror(errno));
+        return -1;
+    }
+
+    MD5_Final(md5, &md5_ctx);
+
+    for (i = 0; i < (int)sizeof(md5); i++)
+        printf("%02x", md5[i]);
+    printf("  %s\n", path);
+
+    return 0;
+}
+
+int md5_main(int argc, char *argv[])
+{
+    int i, ret = 0;
+
+    if (argc < 2)
+        return usage();
+
+    /* loop over the file args */
+    for (i = 1; i < argc; i++) {
+        if (do_md5(argv[i]))
+            ret = 1;
+    }
+
+    return ret;
+}