mirror of https://github.com/Icinga/icinga2.git
100 lines
3.0 KiB
C++
100 lines
3.0 KiB
C++
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/*
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* popen_noshell: A faster implementation of popen() and system() for Linux.
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* Copyright (c) 2009 Ivan Zahariev (famzah)
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* Credits for the C++ test cases go to David Coz
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* Version: 1.0
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU Lesser General Public License as published by
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* the Free Software Foundation; under version 3 of the License.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses>.
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*/
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#include "popen_noshell.h"
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#include <err.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <alloca.h>
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/*****************************************************
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* popen_noshell C++ unit test and use-case examples *
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*****************************************************
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*
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* Compile and test via:
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* g++ -Wall popen_noshell.c popen_noshell_tests.cpp -o popen_noshell_tests_cpp && ./popen_noshell_tests_cpp
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*/
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#define DUMMY_SIZE 10000
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// Just a dummy structure that allocates memory at startup and releases it
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// when exit() is called.
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struct Dummy {
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Dummy() {
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val = new char[DUMMY_SIZE];
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}
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~Dummy() {
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delete[] val;
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val = NULL;
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}
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char* val;
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};
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static Dummy dummy;
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int main() {
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FILE *fp;
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char buf[256];
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int status;
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struct popen_noshell_pass_to_pclose pclose_arg;
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popen_noshell_set_fork_mode(POPEN_NOSHELL_MODE_CLONE);
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// We provide an invalid command, so that the child calls exit().
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// Child's exit() will result in destruction of global objects, while these
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// objects belong to the parent!
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// Therefore, if the parent uses them after child's exit(), it is likely to
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// lead to a crash.
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//char *exec_file = (char *) "ls";
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char *exec_file = (char *) "lsaaa";
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char *arg1 = (char *) "-la";
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char *arg2 = (char *) "/proc/self/fd";
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char *arg3 = (char *) NULL; /* last element */
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char *argv[] = {exec_file, arg1, arg2, arg3}; /* NOTE! The first argv[] must be the executed *exec_file itself */
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fp = popen_noshell(argv[0], (const char * const *)argv, "r", &pclose_arg, 0);
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if (!fp) {
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err(EXIT_FAILURE, "popen_noshell()");
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}
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while (fgets(buf, sizeof(buf)-1, fp)) {
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printf("Got line: %s", buf);
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}
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status = pclose_noshell(&pclose_arg);
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if (status == -1) {
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err(EXIT_FAILURE, "pclose_noshell()");
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} else {
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printf("The status of the child is %d. Note that this is not only the exit code. See man waitpid().\n", status);
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}
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// Trying to access our global variable stuff.
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// If exit() is used in the child process, dummy.val = 0 and we have a crash.
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// With _exit(), dummy.val is still valid.
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// printf("Accessing dummy stuff. dummy.val=%p\n", dummy.val);
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memset(dummy.val, 42, DUMMY_SIZE);
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printf("\nTests passed OK.\n");
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return 0;
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}
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