170 lines
3.8 KiB
C
170 lines
3.8 KiB
C
/*
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* libifupdown/execute.c
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* Purpose: execution of individual commands
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*
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* Copyright (c) 2020 Ariadne Conill <ariadne@dereferenced.org>
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*
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* Permission to use, copy, modify, and/or 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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* copyright notice and this permission notice appear in all copies.
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*
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* This software is provided 'as is' and without any warranty, express or
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* implied. In no event shall the authors be liable for any damages arising
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* from the use of this software.
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*/
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#include <errno.h>
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#include <stdarg.h>
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#include <stddef.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 <spawn.h>
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#include <sys/stat.h>
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#include <sys/types.h>
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#include <sys/wait.h>
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#include <unistd.h>
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#include <poll.h>
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#include "libifupdown/execute.h"
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#define SHELL "/bin/sh"
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bool
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lif_execute_fmt(const struct lif_execute_opts *opts, char *const envp[], const char *fmt, ...)
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{
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char cmdbuf[4096];
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va_list va;
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va_start(va, fmt);
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vsnprintf(cmdbuf, sizeof cmdbuf, fmt, va);
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va_end(va);
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pid_t child;
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char *argv[] = { SHELL, "-c", cmdbuf, NULL };
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if (opts->verbose)
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puts(cmdbuf);
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if (opts->mock)
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return true;
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if (posix_spawn(&child, SHELL, NULL, NULL, argv, envp) != 0)
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{
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fprintf(stderr, "execute '%s': %s\n", cmdbuf, strerror(errno));
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return false;
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}
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int status;
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waitpid(child, &status, 0);
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return WIFEXITED(status) && WEXITSTATUS(status) == 0;
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}
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bool
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lif_execute_fmt_with_result(const struct lif_execute_opts *opts, char *buf, size_t bufsize, char *const envp[], const char *fmt, ...)
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{
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char cmdbuf[4096];
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va_list va;
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va_start(va, fmt);
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vsnprintf(cmdbuf, sizeof cmdbuf, fmt, va);
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va_end(va);
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pid_t child;
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char *argv[] = { SHELL, "-c", cmdbuf, NULL };
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if (opts->verbose)
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puts(cmdbuf);
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if (opts->mock)
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return true;
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int pipefds[2];
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if (pipe(pipefds) < 0)
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{
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fprintf(stderr, "execute '%s': %s\n", cmdbuf, strerror(errno));
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return false;
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}
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posix_spawn_file_actions_t file_actions;
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posix_spawn_file_actions_init(&file_actions);
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posix_spawn_file_actions_addclose(&file_actions, pipefds[0]);
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posix_spawn_file_actions_adddup2(&file_actions, pipefds[1], 1);
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posix_spawn_file_actions_addclose(&file_actions, pipefds[1]);
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if (posix_spawn(&child, SHELL, &file_actions, NULL, argv, envp) != 0)
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{
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fprintf(stderr, "execute '%s': %s\n", cmdbuf, strerror(errno));
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return false;
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}
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close(pipefds[1]);
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struct pollfd pfd = {
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.fd = pipefds[0],
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.events = POLLIN
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};
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if (poll(&pfd, 1, -1) < 1)
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goto no_result;
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if (read(pipefds[0], buf, bufsize) < 0)
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{
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fprintf(stderr, "reading from pipe: %s\n", strerror(errno));
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return false;
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}
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int status;
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no_result:
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waitpid(child, &status, 0);
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return WIFEXITED(status) && WEXITSTATUS(status) == 0;
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}
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bool
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lif_file_is_executable(const char *path)
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{
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struct stat st;
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if (stat(path, &st))
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return false;
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if (!S_ISREG(st.st_mode))
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return false;
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return !access(path, X_OK);
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}
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bool
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lif_maybe_run_executor(const struct lif_execute_opts *opts, char *const envp[], const char *executor)
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{
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if (opts->verbose)
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fprintf(stderr, "ifupdown: attempting to run %s executor\n", executor);
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char pathbuf[4096];
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snprintf(pathbuf, sizeof pathbuf, "%s/%s", opts->executor_path, executor);
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if (!lif_file_is_executable(pathbuf))
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return true;
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return lif_execute_fmt(opts, envp, "%s", pathbuf);
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}
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bool
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lif_maybe_run_executor_with_result(const struct lif_execute_opts *opts, char *const envp[], const char *executor, char *buf, size_t bufsize)
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{
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if (opts->verbose)
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fprintf(stderr, "ifupdown: attempting to run %s executor\n", executor);
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char pathbuf[4096];
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snprintf(pathbuf, sizeof pathbuf, "%s/%s", opts->executor_path, executor);
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if (!lif_file_is_executable(pathbuf))
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return true;
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return lif_execute_fmt_with_result(opts, buf, bufsize, envp, "%s", pathbuf);
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}
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