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ab1f8b836e0a65235cb74168db5a83b2b6f74330
android_bootable_recovery/edify/expr.c
Doug Zongker 5b695f393e make StringValue wrapper okay to call on NULL 
The docs say "don't do this", but it's trivial to make safe.  Make
StringValue(NULL) return NULL instead of crashing.

Change-Id: I2221bcb4c98d8adb4e25c764d7bdcfa787822bcf
2010-02-24 15:05:07 -08:00

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/*
* Copyright (C) 2009 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 <string.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <stdarg.h>
#include <unistd.h>
#include "expr.h"
// Functions should:
//
// - return a malloc()'d string
// - if Evaluate() on any argument returns NULL, return NULL.
int BooleanString(const char* s) {
return s[0] != '\0';
}
char* Evaluate(State* state, Expr* expr) {
Value* v = expr->fn(expr->name, state, expr->argc, expr->argv);
if (v == NULL) return NULL;
if (v->type != VAL_STRING) {
ErrorAbort(state, "expecting string, got value type %d", v->type);
FreeValue(v);
return NULL;
}
char* result = v->data;
free(v);
return result;
}
Value* EvaluateValue(State* state, Expr* expr) {
return expr->fn(expr->name, state, expr->argc, expr->argv);
}
Value* StringValue(char* str) {
if (str == NULL) return NULL;
Value* v = malloc(sizeof(Value));
v->type = VAL_STRING;
v->size = strlen(str);
v->data = str;
return v;
}
void FreeValue(Value* v) {
if (v == NULL) return;
free(v->data);
free(v);
}
Value* ConcatFn(const char* name, State* state, int argc, Expr* argv[]) {
if (argc == 0) {
return StringValue(strdup(""));
}
char** strings = malloc(argc * sizeof(char*));
int i;
for (i = 0; i < argc; ++i) {
strings[i] = NULL;
}
char* result = NULL;
int length = 0;
for (i = 0; i < argc; ++i) {
strings[i] = Evaluate(state, argv[i]);
if (strings[i] == NULL) {
goto done;
}
length += strlen(strings[i]);
}
result = malloc(length+1);
int p = 0;
for (i = 0; i < argc; ++i) {
strcpy(result+p, strings[i]);
p += strlen(strings[i]);
}
result[p] = '\0';
done:
for (i = 0; i < argc; ++i) {
free(strings[i]);
}
free(strings);
return StringValue(result);
}
Value* IfElseFn(const char* name, State* state, int argc, Expr* argv[]) {
if (argc != 2 && argc != 3) {
free(state->errmsg);
state->errmsg = strdup("ifelse expects 2 or 3 arguments");
return NULL;
}
char* cond = Evaluate(state, argv[0]);
if (cond == NULL) {
return NULL;
}
if (BooleanString(cond) == true) {
free(cond);
return EvaluateValue(state, argv[1]);
} else {
if (argc == 3) {
free(cond);
return EvaluateValue(state, argv[2]);
} else {
return StringValue(cond);
}
}
}
Value* AbortFn(const char* name, State* state, int argc, Expr* argv[]) {
char* msg = NULL;
if (argc > 0) {
msg = Evaluate(state, argv[0]);
}
free(state->errmsg);
if (msg) {
state->errmsg = msg;
} else {
state->errmsg = strdup("called abort()");
}
return NULL;
}
Value* AssertFn(const char* name, State* state, int argc, Expr* argv[]) {
int i;
for (i = 0; i < argc; ++i) {
char* v = Evaluate(state, argv[i]);
if (v == NULL) {
return NULL;
}
int b = BooleanString(v);
free(v);
if (!b) {
int prefix_len;
int len = argv[i]->end - argv[i]->start;
char* err_src = malloc(len + 20);
strcpy(err_src, "assert failed: ");
prefix_len = strlen(err_src);
memcpy(err_src + prefix_len, state->script + argv[i]->start, len);
err_src[prefix_len + len] = '\0';
free(state->errmsg);
state->errmsg = err_src;
return NULL;
}
}
return StringValue(strdup(""));
}
Value* SleepFn(const char* name, State* state, int argc, Expr* argv[]) {
char* val = Evaluate(state, argv[0]);
if (val == NULL) {
return NULL;
}
int v = strtol(val, NULL, 10);
sleep(v);
return StringValue(val);
}
Value* StdoutFn(const char* name, State* state, int argc, Expr* argv[]) {
int i;
for (i = 0; i < argc; ++i) {
char* v = Evaluate(state, argv[i]);
if (v == NULL) {
return NULL;
}
fputs(v, stdout);
free(v);
}
return StringValue(strdup(""));
}
Value* LogicalAndFn(const char* name, State* state,
int argc, Expr* argv[]) {
char* left = Evaluate(state, argv[0]);
if (left == NULL) return NULL;
if (BooleanString(left) == true) {
free(left);
return EvaluateValue(state, argv[1]);
} else {
return StringValue(left);
}
}
Value* LogicalOrFn(const char* name, State* state,
int argc, Expr* argv[]) {
char* left = Evaluate(state, argv[0]);
if (left == NULL) return NULL;
if (BooleanString(left) == false) {
free(left);
return EvaluateValue(state, argv[1]);
} else {
return StringValue(left);
}
}
Value* LogicalNotFn(const char* name, State* state,
int argc, Expr* argv[]) {
char* val = Evaluate(state, argv[0]);
if (val == NULL) return NULL;
bool bv = BooleanString(val);
free(val);
return StringValue(strdup(bv ? "" : "t"));
}
Value* SubstringFn(const char* name, State* state,
int argc, Expr* argv[]) {
char* needle = Evaluate(state, argv[0]);
if (needle == NULL) return NULL;
char* haystack = Evaluate(state, argv[1]);
if (haystack == NULL) {
free(needle);
return NULL;
}
char* result = strdup(strstr(haystack, needle) ? "t" : "");
free(needle);
free(haystack);
return StringValue(result);
}
Value* EqualityFn(const char* name, State* state, int argc, Expr* argv[]) {
char* left = Evaluate(state, argv[0]);
if (left == NULL) return NULL;
char* right = Evaluate(state, argv[1]);
if (right == NULL) {
free(left);
return NULL;
}
char* result = strdup(strcmp(left, right) == 0 ? "t" : "");
free(left);
free(right);
return StringValue(result);
}
Value* InequalityFn(const char* name, State* state, int argc, Expr* argv[]) {
char* left = Evaluate(state, argv[0]);
if (left == NULL) return NULL;
char* right = Evaluate(state, argv[1]);
if (right == NULL) {
free(left);
return NULL;
}
char* result = strdup(strcmp(left, right) != 0 ? "t" : "");
free(left);
free(right);
return StringValue(result);
}
Value* SequenceFn(const char* name, State* state, int argc, Expr* argv[]) {
Value* left = EvaluateValue(state, argv[0]);
if (left == NULL) return NULL;
FreeValue(left);
return EvaluateValue(state, argv[1]);
}
Value* LessThanIntFn(const char* name, State* state, int argc, Expr* argv[]) {
if (argc != 2) {
free(state->errmsg);
state->errmsg = strdup("less_than_int expects 2 arguments");
return NULL;
}
char* left;
char* right;
if (ReadArgs(state, argv, 2, &left, &right) < 0) return NULL;
bool result = false;
char* end;
long l_int = strtol(left, &end, 10);
if (left[0] == '\0' || *end != '\0') {
fprintf(stderr, "[%s] is not an int\n", left);
goto done;
}
long r_int = strtol(right, &end, 10);
if (right[0] == '\0' || *end != '\0') {
fprintf(stderr, "[%s] is not an int\n", right);
goto done;
}
result = l_int < r_int;
done:
free(left);
free(right);
return StringValue(strdup(result ? "t" : ""));
}
Value* GreaterThanIntFn(const char* name, State* state,
int argc, Expr* argv[]) {
if (argc != 2) {
free(state->errmsg);
state->errmsg = strdup("greater_than_int expects 2 arguments");
return NULL;
}
Expr* temp[2];
temp[0] = argv[1];
temp[1] = argv[0];
return LessThanIntFn(name, state, 2, temp);
}
Value* Literal(const char* name, State* state, int argc, Expr* argv[]) {
return StringValue(strdup(name));
}
Expr* Build(Function fn, YYLTYPE loc, int count, ...) {
va_list v;
va_start(v, count);
Expr* e = malloc(sizeof(Expr));
e->fn = fn;
e->name = "(operator)";
e->argc = count;
e->argv = malloc(count * sizeof(Expr*));
int i;
for (i = 0; i < count; ++i) {
e->argv[i] = va_arg(v, Expr*);
}
va_end(v);
e->start = loc.start;
e->end = loc.end;
return e;
}
// -----------------------------------------------------------------
// the function table
// -----------------------------------------------------------------
static int fn_entries = 0;
static int fn_size = 0;
NamedFunction* fn_table = NULL;
void RegisterFunction(const char* name, Function fn) {
if (fn_entries >= fn_size) {
fn_size = fn_size*2 + 1;
fn_table = realloc(fn_table, fn_size * sizeof(NamedFunction));
}
fn_table[fn_entries].name = name;
fn_table[fn_entries].fn = fn;
++fn_entries;
}
static int fn_entry_compare(const void* a, const void* b) {
const char* na = ((const NamedFunction*)a)->name;
const char* nb = ((const NamedFunction*)b)->name;
return strcmp(na, nb);
}
void FinishRegistration() {
qsort(fn_table, fn_entries, sizeof(NamedFunction), fn_entry_compare);
}
Function FindFunction(const char* name) {
NamedFunction key;
key.name = name;
NamedFunction* nf = bsearch(&key, fn_table, fn_entries,
sizeof(NamedFunction), fn_entry_compare);
if (nf == NULL) {
return NULL;
}
return nf->fn;
}
void RegisterBuiltins() {
RegisterFunction("ifelse", IfElseFn);
RegisterFunction("abort", AbortFn);
RegisterFunction("assert", AssertFn);
RegisterFunction("concat", ConcatFn);
RegisterFunction("is_substring", SubstringFn);
RegisterFunction("stdout", StdoutFn);
RegisterFunction("sleep", SleepFn);
RegisterFunction("less_than_int", LessThanIntFn);
RegisterFunction("greater_than_int", GreaterThanIntFn);
}
// -----------------------------------------------------------------
// convenience methods for functions
// -----------------------------------------------------------------
// Evaluate the expressions in argv, giving 'count' char* (the ... is
// zero or more char** to put them in). If any expression evaluates
// to NULL, free the rest and return -1. Return 0 on success.
int ReadArgs(State* state, Expr* argv[], int count, ...) {
char** args = malloc(count * sizeof(char*));
va_list v;
va_start(v, count);
int i;
for (i = 0; i < count; ++i) {
args[i] = Evaluate(state, argv[i]);
if (args[i] == NULL) {
va_end(v);
int j;
for (j = 0; j < i; ++j) {
free(args[j]);
}
free(args);
return -1;
}
*(va_arg(v, char**)) = args[i];
}
va_end(v);
free(args);
return 0;
}
// Evaluate the expressions in argv, giving 'count' Value* (the ... is
// zero or more Value** to put them in). If any expression evaluates
// to NULL, free the rest and return -1. Return 0 on success.
int ReadValueArgs(State* state, Expr* argv[], int count, ...) {
Value** args = malloc(count * sizeof(Value*));
va_list v;
va_start(v, count);
int i;
for (i = 0; i < count; ++i) {
args[i] = EvaluateValue(state, argv[i]);
if (args[i] == NULL) {
va_end(v);
int j;
for (j = 0; j < i; ++j) {
FreeValue(args[j]);
}
free(args);
return -1;
}
*(va_arg(v, Value**)) = args[i];
}
va_end(v);
free(args);
return 0;
}
// Evaluate the expressions in argv, returning an array of char*
// results. If any evaluate to NULL, free the rest and return NULL.
// The caller is responsible for freeing the returned array and the
// strings it contains.
char** ReadVarArgs(State* state, int argc, Expr* argv[]) {
char** args = (char**)malloc(argc * sizeof(char*));
int i = 0;
for (i = 0; i < argc; ++i) {
args[i] = Evaluate(state, argv[i]);
if (args[i] == NULL) {
int j;
for (j = 0; j < i; ++j) {
free(args[j]);
}
free(args);
return NULL;
}
}
return args;
}
// Evaluate the expressions in argv, returning an array of Value*
// results. If any evaluate to NULL, free the rest and return NULL.
// The caller is responsible for freeing the returned array and the
// Values it contains.
Value** ReadValueVarArgs(State* state, int argc, Expr* argv[]) {
Value** args = (Value**)malloc(argc * sizeof(Value*));
int i = 0;
for (i = 0; i < argc; ++i) {
args[i] = EvaluateValue(state, argv[i]);
if (args[i] == NULL) {
int j;
for (j = 0; j < i; ++j) {
FreeValue(args[j]);
}
free(args);
return NULL;
}
}
return args;
}
// Use printf-style arguments to compose an error message to put into
// *state. Returns NULL.
Value* ErrorAbort(State* state, char* format, ...) {
char* buffer = malloc(4096);
va_list v;
va_start(v, format);
vsnprintf(buffer, 4096, format, v);
va_end(v);
free(state->errmsg);
state->errmsg = buffer;
return NULL;
}
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