/* resetprop.cpp - Manipulate any system props * * Copyright 2016 nkk71 <nkk71x@gmail.com> * Copyright 2016 topjohnwu <topjohnwu@gmail.com> * * Info: * * all changes are in * * bionic/libc/bionic/system_properties.cpp * * Functions that need to be patched/added in system_properties.cpp * * int __system_properties_init2() * on android 7, first tear down the everything then let it initialize again: * if (initialized) { * //list_foreach(contexts, [](context_node* l) { l->reset_access(); }); * //return 0; * free_and_unmap_contexts(); * initialized = false; * } * * * static prop_area* map_prop_area(const char* filename, bool is_legacy) * we dont want this read only so change: 'O_RDONLY' to 'O_RDWR' * * static prop_area* map_fd_ro(const int fd) * we dont want this read only so change: 'PROT_READ' to 'PROT_READ | PROT_WRITE' * * * Copy the code of prop_info *prop_area::find_property, and modify to delete props * const prop_info *prop_area::find_property_and_del(prop_bt *const trie, const char *name) * { * ... * ... Do not alloc a new prop_bt here, remove all code involve alloc_if_needed * ... * * if (prop_offset != 0) { * atomic_store_explicit(¤t->prop, 0, memory_order_release); // Add this line to nullify the prop entry * return to_prop_info(¤t->prop); * } else { * * .... * } * * * by patching just those functions directly, all other functions should be ok * as is. * * */ #include <stdio.h> #include <stdint.h> #include <stdlib.h> #include <unistd.h> #include <fcntl.h> #include <string.h> #include <sys/types.h> #define _REALLY_INCLUDE_SYS__SYSTEM_PROPERTIES_H_ #include "_system_properties.h" #include "system_properties.h" #include "magisk.h" #include "resetprop.h" #define PRINT_D(...) { LOGD(__VA_ARGS__); if (verbose) printf(__VA_ARGS__); } #define PRINT_E(...) { LOGE(__VA_ARGS__); fprintf(stderr, __VA_ARGS__); } static int verbose = 0; static bool is_legal_property_name(const char* name, size_t namelen) { if (namelen < 1) return false; if (name[0] == '.') return false; if (name[namelen - 1] == '.') return false; /* Only allow alphanumeric, plus '.', '-', or '_' */ /* Don't allow ".." to appear in a property name */ for (size_t i = 0; i < namelen; i++) { if (name[i] == '.') { // i=0 is guaranteed to never have a dot. See above. if (name[i - 1] == '.') return false; continue; } if (name[i] == '_' || name[i] == '-') continue; if (name[i] >= 'a' && name[i] <= 'z') continue; if (name[i] >= 'A' && name[i] <= 'Z') continue; if (name[i] >= '0' && name[i] <= '9') continue; return false; } return true; } static int usage(char* arg0) { fprintf(stderr, "resetprop v" xstr(MAGISK_VERSION) "(" xstr(MAGISK_VER_CODE) ") (by topjohnwu & nkk71) - System Props Modification Tool\n\n" "Usage: %s [options] [args...]\n" "%s <name> <value>: Set property entry <name> with <value>\n" "%s --file <prop file>: Load props from <prop file>\n" "%s --delete <name>: Remove prop entry <name>\n" "\n" "Options:\n" " -v verbose output\n" " -n don't trigger events when changing props\n" , arg0, arg0, arg0, arg0); return 1; } static int init_resetprop() { if (__system_properties_init2()) { PRINT_E("resetprop: Initialize error\n"); return -1; } return 0; } int prop_exist(const char *name) { if (init_resetprop()) return 0; return __system_property_find2(name) != NULL; } static void read_prop_info(void* cookie, const char *name, const char *value, uint32_t serial) { strcpy((char *) cookie, value); } // Get prop by name, return string (should free manually!) char *getprop(const char *name) { if (init_resetprop()) return NULL; const prop_info *pi = __system_property_find2(name); if (pi == NULL) { PRINT_D("resetprop: prop [%s] does not exist\n", name); return NULL; } char value[PROP_VALUE_MAX]; __system_property_read_callback2(pi, read_prop_info, value); PRINT_D("resetprop: getprop [%s]: [%s]\n", name, value); return strdup(value); } int setprop(const char *name, const char *value) { return setprop2(name, value, 1); } int setprop2(const char *name, const char *value, const int trigger) { if (init_resetprop()) return -1; int ret; prop_info *pi = (prop_info*) __system_property_find2(name); if (pi != NULL) { if (trigger) { if (!strncmp(name, "ro.", 3)) deleteprop(name); ret = __system_property_set2(name, value); } else { ret = __system_property_update2(pi, value, strlen(value)); } } else { PRINT_D("resetprop: New prop [%s]\n", name); if (trigger) { ret = __system_property_set2(name, value); } else { ret = __system_property_add2(name, strlen(name), value, strlen(value)); } } PRINT_D("resetprop: setprop [%s]: [%s] by %s\n", name, value, trigger ? "property_service" : "modifing prop data structure"); if (ret) PRINT_E("resetprop: setprop error\n"); return ret; } int deleteprop(const char *name) { if (init_resetprop()) return -1; PRINT_D("resetprop: deleteprop [%s]\n", name); if (__system_property_del(name)) { PRINT_E("resetprop: delete prop: [%s] error\n", name); return -1; } return 0; } int read_prop_file(const char* filename, const int trigger) { if (init_resetprop()) return -1; PRINT_D("resetprop: Load prop file [%s]\n", filename); FILE *fp = fopen(filename, "r"); if (fp == NULL) { PRINT_E("Cannot open [%s]\n", filename); return 1; } char *line = NULL, *pch; size_t len; ssize_t read; int comment = 0, i; while ((read = getline(&line, &len, fp)) != -1) { // Remove the trailing newline if (line[read - 1] == '\n') { line[read - 1] = '\0'; --read; } comment = 0; for (i = 0; i < read; ++i) { // Ignore starting spaces if (line[i] == ' ') continue; else { // A line starting with # is ignored if (line[i] == '#') comment = 1; break; } } if (comment) continue; pch = strchr(line, '='); // Ignore ivalid formats if ( ((pch == NULL) || (i >= (pch - line))) || (pch >= line + read - 1) ) continue; // Separate the string *pch = '\0'; setprop2(line + i, pch + 1, trigger); } free(line); fclose(fp); return 0; } int resetprop_main(int argc, char *argv[]) { int del = 0, file = 0, trigger = 1; int exp_arg = 2; char *name, *value, *filename; if (argc < 3) { return usage(argv[0]); } for (int i = 1; i < argc; ++i) { if (!strcmp("-v", argv[i])) { verbose = 1; } else if (!strcmp("-n", argv[i])) { trigger = 0; } else if (!strcmp("--file", argv[i])) { file = 1; exp_arg = 1; } else if (!strcmp("--delete", argv[i])) { del = 1; exp_arg = 1; } else { if (i + exp_arg > argc) { return usage(argv[0]); } if (file) { filename = argv[i]; break; } else { if(!is_legal_property_name(argv[i], strlen(argv[i]))) { PRINT_E("Illegal property name: [%s]\n", argv[i]); return 1; } name = argv[i]; if (exp_arg > 1) { if (strlen(argv[i + 1]) >= PROP_VALUE_MAX) { PRINT_E("Value too long: [%s]\n", argv[i + 1]); return 1; } value = argv[i + 1]; } break; } } } if (file) { return read_prop_file(filename, trigger); } else if (del) { return deleteprop(name); } else { return setprop2(name, value, trigger); } return 0; }