Check overflow in expr(1).
This commit is contained in:
Jonas 'Sortie' Termansen
parent
2a6a246ff4
commit
e4a3bb997b
173
utils/expr.c
173
utils/expr.c
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@ -1,5 +1,5 @@
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/*
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* Copyright (c) 2014 Jonas 'Sortie' Termansen.
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* Copyright (c) 2014, 2015, 2016 Jonas 'Sortie' Termansen.
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*
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* Permission to use, copy, modify, and distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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@ -17,8 +17,9 @@
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* Evaluate expressions.
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*/
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#include <ctype.h>
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#include <err.h>
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#include <errno.h>
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#include <error.h>
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#include <inttypes.h>
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#include <locale.h>
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#include <regex.h>
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@ -34,58 +35,71 @@
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// `expr + 5 + + 2 +'
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// TODO: Support the other GNU function extensions documented in help().
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char* strdup_or_die(const char* str)
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static bool integer_of_string(const char* str, intmax_t* out)
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{
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if ( !isdigit((unsigned char) str[0]) )
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return false;
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char* endptr;
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errno = 0;
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intmax_t result = strtoimax((char*) str, &endptr, 10);
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if ( (result == INTMAX_MIN || result == INTMAX_MAX) && errno == ERANGE )
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return false;
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if ( *endptr )
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return false;
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return *out = result, true;
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}
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static char* strdup_or_die(const char* str)
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{
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char* result = strdup(str);
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if ( !str )
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error(2, errno, "strdup");
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err(2, "strdup");
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return result;
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}
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char* strndup_or_die(const char* str, size_t n)
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static char* strndup_or_die(const char* str, size_t n)
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{
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char* result = strndup(str, n);
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if ( !str )
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error(2, errno, "strndup");
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err(2, "strndup");
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return result;
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}
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char* print_intmax_or_die(intmax_t value)
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static char* print_intmax_or_die(intmax_t value)
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{
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char value_string[sizeof(intmax_t) * 3];
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snprintf(value_string, sizeof(value_string), "%ji", value);
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return strdup_or_die(value_string);
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}
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__attribute__((noreturn))
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void syntax_error(void)
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static void syntax_error(void)
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{
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error(2, 0, "syntax error");
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__builtin_unreachable();
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errx(2, "syntax error");
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}
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__attribute__((noreturn))
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void non_integer_argument(void)
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static void non_integer_argument(void)
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{
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error(2, 0, "non-integer argument");
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__builtin_unreachable();
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errx(2, "non-integer argument");
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}
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__attribute__((noreturn))
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void division_by_zero(void)
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static void division_by_zero(void)
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{
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error(2, 0, "division by zero");
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__builtin_unreachable();
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errx(2, "division by zero");
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}
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char* interpret(char** tokens, size_t num_tokens);
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static void overflow(const char* op)
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{
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errx(2, "%s overflow", op);
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}
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char* interpret_left_associative(char** tokens,
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size_t num_tokens,
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const char* operator_name,
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char* (*next)(char**, size_t, const void*),
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const void* next_context,
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char* (*function)(const char*, const char*))
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static char* interpret(char** tokens, size_t num_tokens);
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static char* interpret_left_associative(char** tokens,
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size_t num_tokens,
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const char* operator_name,
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char* (*next)(char**, size_t, const void*),
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const void* next_context,
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char* (*function)(const char*, const char*))
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{
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size_t depth = 0;
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for ( size_t n = num_tokens; n != 0; n-- )
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@ -132,14 +146,14 @@ char* interpret_left_associative(char** tokens,
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return next(tokens, num_tokens, next_context);
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}
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char* bool_to_boolean_value(bool b)
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static char* bool_to_boolean_value(bool b)
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{
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return strdup_or_die(b ? "1" : "0");
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}
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char* interpret_literal(char** tokens,
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size_t num_tokens,
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const void* ctx)
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static char* interpret_literal(char** tokens,
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size_t num_tokens,
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const void* ctx)
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{
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(void) ctx;
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if ( num_tokens != 1 )
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@ -147,9 +161,9 @@ char* interpret_literal(char** tokens,
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return strdup_or_die(tokens[0]);
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}
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char* interpret_parentheses(char** tokens,
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size_t num_tokens,
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const void* ctx)
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static char* interpret_parentheses(char** tokens,
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size_t num_tokens,
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const void* ctx)
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{
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if ( 2 <= num_tokens &&
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strcmp(tokens[0], "(") == 0 &&
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@ -158,7 +172,7 @@ char* interpret_parentheses(char** tokens,
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return interpret_literal(tokens, num_tokens, ctx);
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}
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char* evaluate_and(const char* a, const char* b)
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static char* evaluate_and(const char* a, const char* b)
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{
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if ( strcmp(a, "") != 0 && strcmp(a, "0") != 0 &&
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strcmp(b, "") != 0 && strcmp(b, "0") != 0 )
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@ -166,7 +180,7 @@ char* evaluate_and(const char* a, const char* b)
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return strdup_or_die("0");
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}
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char* evaluate_or(const char* a, const char* b)
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static char* evaluate_or(const char* a, const char* b)
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{
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if ( strcmp(a, "") != 0 && strcmp(a, "0") != 0 )
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return strdup_or_die(a);
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@ -175,14 +189,11 @@ char* evaluate_or(const char* a, const char* b)
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return strdup_or_die("0");
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}
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int compare_values(const char* a, const char* b)
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static int compare_values(const char* a, const char* b)
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{
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// TODO: Compute using arbitrary length integers.
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char* a_endptr;
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char* b_endptr;
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intmax_t a_int = strtoimax((char*) a, &a_endptr, 10);
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intmax_t b_int = strtoimax((char*) b, &b_endptr, 10);
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if ( a[0] && !*a_endptr && b[0] && !*b_endptr )
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intmax_t a_int, b_int;
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if ( integer_of_string(a, &a_int) &&
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integer_of_string(b, &b_int) )
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{
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if ( a_int < b_int )
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return -1;
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@ -193,104 +204,116 @@ int compare_values(const char* a, const char* b)
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return strcoll(a, b);
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}
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char* evaluate_eq(const char* a, const char* b)
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static char* evaluate_eq(const char* a, const char* b)
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{
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return bool_to_boolean_value(compare_values(a, b) == 0);
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}
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char* evaluate_gt(const char* a, const char* b)
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static char* evaluate_gt(const char* a, const char* b)
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{
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return bool_to_boolean_value(0 < compare_values(a, b));
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}
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char* evaluate_ge(const char* a, const char* b)
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static char* evaluate_ge(const char* a, const char* b)
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{
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return bool_to_boolean_value(0 <= compare_values(a, b));
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}
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char* evaluate_lt(const char* a, const char* b)
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static char* evaluate_lt(const char* a, const char* b)
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{
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return bool_to_boolean_value(compare_values(a, b) < 0);
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}
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char* evaluate_le(const char* a, const char* b)
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static char* evaluate_le(const char* a, const char* b)
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{
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return bool_to_boolean_value(compare_values(a, b) <= 0);
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}
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char* evaluate_neq(const char* a, const char* b)
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static char* evaluate_neq(const char* a, const char* b)
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{
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return bool_to_boolean_value(compare_values(a, b) != 0);
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}
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char* evaluate_integer_function(const char* a, const char* b,
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intmax_t (*function)(intmax_t, intmax_t))
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static char* evaluate_integer_function(const char* a, const char* b,
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intmax_t (*function)(intmax_t, intmax_t))
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{
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// TODO: Compute using arbitrary length integers.
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char* a_endptr;
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char* b_endptr;
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intmax_t a_int = strtoimax((char*) a, &a_endptr, 10);
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intmax_t b_int = strtoimax((char*) b, &b_endptr, 10);
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if ( !a[0] || *a_endptr || !b[0] || *b_endptr )
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intmax_t a_int;
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intmax_t b_int;
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if ( !integer_of_string(a, &a_int) ||
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!integer_of_string(b, &b_int) )
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non_integer_argument();
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return print_intmax_or_die(function(a_int, b_int));
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}
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intmax_t integer_add(intmax_t a, intmax_t b)
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static intmax_t integer_add(intmax_t a, intmax_t b)
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{
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return a + b;
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intmax_t result = 0;
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if ( __builtin_add_overflow(a, b, &result) )
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overflow("addition");
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return result;
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}
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char* evaluate_add(const char* a, const char* b)
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static char* evaluate_add(const char* a, const char* b)
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{
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return evaluate_integer_function(a, b, integer_add);
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}
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intmax_t integer_sub(intmax_t a, intmax_t b)
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static intmax_t integer_sub(intmax_t a, intmax_t b)
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{
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return a - b;
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intmax_t result = 0;
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if ( __builtin_sub_overflow(a, b, &result) )
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overflow("subtraction");
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return result;
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}
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char* evaluate_sub(const char* a, const char* b)
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static char* evaluate_sub(const char* a, const char* b)
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{
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return evaluate_integer_function(a, b, integer_sub);
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}
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intmax_t integer_mul(intmax_t a, intmax_t b)
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static intmax_t integer_mul(intmax_t a, intmax_t b)
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{
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return a * b;
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intmax_t result = 0;
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if ( __builtin_mul_overflow(a, b, &result) )
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overflow("multiplication");
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return result;
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}
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char* evaluate_mul(const char* a, const char* b)
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static char* evaluate_mul(const char* a, const char* b)
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{
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return evaluate_integer_function(a, b, integer_mul);
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}
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intmax_t integer_div(intmax_t a, intmax_t b)
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static intmax_t integer_div(intmax_t a, intmax_t b)
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{
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if ( b == 0 )
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division_by_zero();
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if ( a == INTMAX_MIN && b == -1 )
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overflow("division");
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return a / b;
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}
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char* evaluate_div(const char* a, const char* b)
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static char* evaluate_div(const char* a, const char* b)
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{
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return evaluate_integer_function(a, b, integer_div);
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}
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intmax_t integer_mod(intmax_t a, intmax_t b)
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// TODO: Is this fully well-defined?
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static intmax_t integer_mod(intmax_t a, intmax_t b)
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{
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if ( b == 0 )
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division_by_zero();
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if ( a == INTMAX_MIN && b == -1 )
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overflow("division");
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return a % b;
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}
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char* evaluate_mod(const char* a, const char* b)
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static char* evaluate_mod(const char* a, const char* b)
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{
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return evaluate_integer_function(a, b, integer_mod);
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}
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char* evaluate_match(const char* a, const char* b)
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static char* evaluate_match(const char* a, const char* b)
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{
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regex_t regex;
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int status = regcomp(®ex, b, 0);
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@ -309,7 +332,7 @@ char* evaluate_match(const char* a, const char* b)
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regerror(status, ®ex, erralloc, errbuf_needed);
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}
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}
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error(2, 0, "compiling regular expression: %s", errmsg);
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errx(2, "compiling regular expression: %s", errmsg);
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free(erralloc);
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}
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@ -360,9 +383,9 @@ struct binary_operator binary_operators[] =
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{ ":", evaluate_match },
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};
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char* interpret_binary_operator(char** tokens,
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size_t num_tokens,
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const void* context)
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static char* interpret_binary_operator(char** tokens,
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size_t num_tokens,
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const void* context)
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{
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size_t index = *(const size_t*) context;
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size_t next_index = index + 1;
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@ -386,7 +409,7 @@ char* interpret_binary_operator(char** tokens,
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next, next_context, binop->function);
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}
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char* interpret(char** tokens, size_t num_tokens)
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static char* interpret(char** tokens, size_t num_tokens)
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{
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if ( !num_tokens )
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syntax_error();
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