atf-c/utils.c:atf_utils_wait is not multiprocess safe #15
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There is currently no expectation for the ATF interface to be thread-safe. But the problem here is not about threads: it's about multiprocessing. It's perfectly reasonable to spawn to subprocess and wait for them with checks, which fails with the current fork/wait interface. As an easy solution, we can tag the generated file names with the spawned PID. Not completely bug-free if the OS decides to reuse PIDs along the way, but most decent OSs nowadays will avoid immediate PID reuse to prevent certain types of attacks. |
lwhsu
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Jan 16, 2024
atf-check.1: stop with extraneous quoting
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Filed from freebsd/kyua#87 by yaneurabeya:
This code is writing to a non-temporary file with a constant filename in order to capture the exec output. This is not multiprocess/multithreading safe:
381 void 382 atf_utils_wait(const pid_t pid, const int exitstatus, const char *expout, 383 const char *experr) 384 { 385 int status; 386 ATF_REQUIRE(waitpid(pid, &status, 0) != -1); 387 388 atf_utils_cat_file("atf_utils_fork_out.txt", "subprocess stdout: "); 389 atf_utils_cat_file("atf_utils_fork_err.txt", "subprocess stderr: "); 390 391 ATF_REQUIRE(WIFEXITED(status)); 392 ATF_REQUIRE_EQ(exitstatus, WEXITSTATUS(status)); 393 394 const char *save_prefix = "save:"; 395 const size_t save_prefix_length = strlen(save_prefix); 396 397 if (strlen(expout) > save_prefix_length && 398 strncmp(expout, save_prefix, save_prefix_length) == 0) { 399 atf_utils_copy_file("atf_utils_fork_out.txt", 400 expout + save_prefix_length); 401 } else { 402 ATF_REQUIRE(atf_utils_compare_file("atf_utils_fork_out.txt", expout)); 403 } 404 405 if (strlen(experr) > save_prefix_length && 406 strncmp(experr, save_prefix, save_prefix_length) == 0) { 407 atf_utils_copy_file("atf_utils_fork_err.txt", 408 experr + save_prefix_length); 409 } else { 410 ATF_REQUIRE(atf_utils_compare_file("atf_utils_fork_err.txt", experr)); 411 } 412 413 ATF_REQUIRE(unlink("atf_utils_fork_out.txt") != -1); 414 ATF_REQUIRE(unlink("atf_utils_fork_err.txt") != -1); 415 }The text was updated successfully, but these errors were encountered: