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/*
* 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", (int)(end - line), line, tag, number, end);
} else {
fprintf(out, "%.*s%s%s", (int)(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;
}
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