1 files changed, 141 insertions, 0 deletions
diff --git a/tools/ota/add-property-tag.c b/tools/ota/add-property-tag.c
new file mode 100644
index 0000000..5277edd
--- /dev/null
+++ b/tools/ota/add-property-tag.c
@@ -0,0 +1,141 @@
+/*
+ * Copyright (C) 2008 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <ctype.h>
+#include <errno.h>
+#include <getopt.h>
+#include <limits.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+/*
+ * Append a tag to a property value in a .prop file if it isn't already there.
+ * Normally used to modify build properties to record incremental updates.
+ */
+
+// Return nonzero if the tag should be added to this line.
+int should_tag(const char *line, const char *propname) {
+    const char *prop = strstr(line, propname);
+    if (prop == NULL) return 0;
+
+    // Make sure this is actually the property name (not an accidental hit)
+    const char *ptr;
+    for (ptr = line; ptr < prop && isspace(*ptr); ++ptr) ;
+    if (ptr != prop) return 0;  // Must be at the beginning of the line
+
+    for (ptr += strlen(propname); *ptr != '\0' && isspace(*ptr); ++ptr) ;
+    return (*ptr == '=');  // Must be followed by a '='
+}
+
+// Remove existing tags from the line, return the following number (if any)
+int remove_tag(char *line, const char *tag) {
+    char *pos = strstr(line, tag);
+    if (pos == NULL) return 0;
+
+    char *end;
+    int num = strtoul(pos + strlen(tag), &end, 10);
+    strcpy(pos, end);
+    return num;
+}
+
+// Write line to output with the tag added, adding a number (if >0)
+void write_tagged(FILE *out, const char *line, const char *tag, int number) {
+    const char *end = line + strlen(line);
+    while (end > line && isspace(end[-1])) --end;
+    if (number > 0) {
+        fprintf(out, "%.*s%s%d%s", end - line, line, tag, number, end);
+    } else {
+        fprintf(out, "%.*s%s%s", end - line, line, tag, end);
+    }
+}
+
+int main(int argc, char **argv) {
+    const char *filename = "/system/build.prop";
+    const char *propname = "ro.build.fingerprint";
+    const char *tag = NULL;
+    int do_remove = 0, do_number = 0;
+
+    int opt;
+    while ((opt = getopt(argc, argv, "f:p:rn")) != -1) {
+        switch (opt) {
+        case 'f': filename = optarg; break;
+        case 'p': propname = optarg; break;
+        case 'r': do_remove = 1; break;
+        case 'n': do_number = 1; break;
+        case '?': return 2;
+        }
+    }
+
+    if (argc != optind + 1) {
+        fprintf(stderr,
+            "usage: add-property-tag [flags] tag-to-add\n"
+            "flags: -f /dir/file.prop (default /system/build.prop)\n"
+            "       -p prop.name (default ro.build.fingerprint)\n"
+            "       -r (if set, remove the tag rather than adding it)\n"
+            "       -n (if set, add and increment a number after the tag)\n");
+        return 2;
+    }
+
+    tag = argv[optind];
+    FILE *input = fopen(filename, "r");
+    if (input == NULL) {
+        fprintf(stderr, "can't read %s: %s\n", filename, strerror(errno));
+        return 1;
+    }
+
+    char tmpname[PATH_MAX];
+    snprintf(tmpname, sizeof(tmpname), "%s.tmp", filename);
+    FILE *output = fopen(tmpname, "w");
+    if (output == NULL) {
+        fprintf(stderr, "can't write %s: %s\n", tmpname, strerror(errno));
+        return 1;
+    }
+
+    int found = 0;
+    char line[4096];
+    while (fgets(line, sizeof(line), input)) {
+        if (!should_tag(line, propname)) {
+            fputs(line, output);  // Pass through unmodified
+        } else {
+            found = 1;
+            int number = remove_tag(line, tag);
+            if (do_remove) {
+                fputs(line, output);  // Remove the tag but don't re-add it
+            } else {
+                write_tagged(output, line, tag, number + do_number);
+            }
+        }
+    }
+
+    fclose(input);
+    fclose(output);
+
+    if (!found) {
+        fprintf(stderr, "property %s not found in %s\n", propname, filename);
+        remove(tmpname);
+        return 1;
+    }
+
+    if (rename(tmpname, filename)) {
+        fprintf(stderr, "can't rename %s to %s: %s\n",
+            tmpname, filename, strerror(errno));
+        remove(tmpname);
+        return 1;
+    }
+
+    return 0;
+}