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112 lines
3.4 KiB
112 lines
3.4 KiB
// RUN: %clang_dfsan %s -o %t && %run %t | FileCheck %s
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// RUN: %clang_dfsan -mllvm -dfsan-args-abi %s -o %t && %run %t | FileCheck %s
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// Tests that the custom implementation of write() does writes with or without
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// a callback set using dfsan_set_write_callback().
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// REQUIRES: stable-runtime
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#include <sanitizer/dfsan_interface.h>
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#include <assert.h>
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#include <fcntl.h>
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#include <stdio.h>
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#include <string.h>
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#include <unistd.h>
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// Check write callback arguments by having the callback store them in
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// the following variables:
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static int last_callback_arg_fd;
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static const void *last_callback_arg_buf;
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static size_t last_callback_arg_count;
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// Allow tests to check the number of callbacks made by incrementing
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// this count. When callbacks are verified, the count is reset.
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static int count_unverified_callbacks = 0;
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// This callbact will be installed using dfsan_set_write_callback()
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// in tests below.
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static void write_callback(int fd, const void *buf, size_t count) {
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// Do not do anything in this function that might call write().
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count_unverified_callbacks++;
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last_callback_arg_fd = fd;
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last_callback_arg_buf = buf;
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last_callback_arg_count = count;
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}
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static void write_string_to_stdout(char *string) {
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char *cur = string;
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int bytes_left = strlen(string);
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while (bytes_left > 0) {
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int res = write(fileno(stdout), cur, bytes_left);
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assert (res >= 0);
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cur += res;
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bytes_left -= res;
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}
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}
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static void test_can_write_without_callback() {
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dfsan_set_write_callback(NULL);
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count_unverified_callbacks = 0;
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char aString[] = "Test that writes work without callback.\n";
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// CHECK: Test that writes work without callback.
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write_string_to_stdout(aString);
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assert(count_unverified_callbacks == 0);
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}
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static void test_can_write_with_callback() {
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dfsan_set_write_callback(write_callback);
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count_unverified_callbacks = 0;
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char stringWithCallback[] = "Test that writes work with callback.\n";
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// CHECK: Test that writes work with callback.
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write_string_to_stdout(stringWithCallback);
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// Data was written, so at least one call to write() was made.
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// Because a write may not process all the bytes it is passed, there
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// may have been several calls to write().
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assert(count_unverified_callbacks > 0);
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count_unverified_callbacks = 0;
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dfsan_set_write_callback(NULL);
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char stringWithoutCallback[] = "Writes work after the callback is removed.\n";
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// CHECK: Writes work after the callback is removed.
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write_string_to_stdout(stringWithoutCallback);
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assert(count_unverified_callbacks == 0);
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}
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static void test_failing_write_runs_callback() {
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// Open /dev/null in read-only mode. Calling write() on fd will fail.
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int fd = open("/dev/null", O_RDONLY);
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assert(fd != -1);
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// Install a callback.
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dfsan_set_write_callback(write_callback);
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// Write to the read-only file handle. The write will fail, but the callback
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// should still be invoked.
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char aString[] = "This text will fail to be written.\n";
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int len = strlen(aString);
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int write_result = write(fd, aString, len);
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assert(write_result == -1);
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assert(count_unverified_callbacks == 1);
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count_unverified_callbacks = 0;
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assert(fd == last_callback_arg_fd);
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assert(aString == last_callback_arg_buf);
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assert(len == last_callback_arg_count);
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close(fd);
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}
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int main(int argc, char* argv[]) {
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test_can_write_without_callback();
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test_can_write_with_callback();
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test_failing_write_runs_callback();
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}
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