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/*
* Copyright (C) 2009 Citrix Ltd.
* Author Vincent Hanquez <vincent.hanquez@eu.citrix.com>
* Author Stefano Stabellini <stefano.stabellini@eu.citrix.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as published
* by the Free Software Foundation; version 2.1 only. with the special
* exception on linking described in file LICENSE.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Lesser General Public License for more details.
*/
#include "libxl_osdeps.h"
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <stdlib.h>
#include <unistd.h>
#include <assert.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <signal.h> /* for SIGKILL */
#include "libxl.h"
#include "libxl_internal.h"
static pid_t libxl_fork(struct libxl_ctx *ctx)
{
pid_t pid;
pid = fork();
if (pid == -1) {
XL_LOG_ERRNO(ctx, XL_LOG_ERROR, "fork failed");
return -1;
}
return pid;
}
static int call_waitpid(pid_t (*waitpid_cb)(pid_t, int *, int), pid_t pid, int *status, int options)
{
return (waitpid_cb) ? waitpid_cb(pid, status, options) : waitpid(pid, status, options);
}
void libxl_exec(struct libxl_ctx *ctx, int stdinfd, int stdoutfd, int stderrfd,
char *arg0, char **args)
/* call this in the child */
{
int i;
if (stdinfd != -1)
dup2(stdinfd, STDIN_FILENO);
if (stdoutfd != -1)
dup2(stdoutfd, STDOUT_FILENO);
if (stderrfd != -1)
dup2(stderrfd, STDERR_FILENO);
for (i = 4; i < 256; i++)
close(i);
execv(arg0, args);
XL_LOG_ERRNO(ctx, XL_LOG_ERROR, "exec %s failed", arg0);
_exit(-1);
}
void libxl_report_child_exitstatus(struct libxl_ctx *ctx,
const char *what, pid_t pid, int status)
{
/* treats all exit statuses as errors; if that's not what you want,
* check status yourself first */
if (WIFEXITED(status)) {
int st = WEXITSTATUS(status);
if (st)
XL_LOG(ctx, XL_LOG_ERROR, "%s [%ld] exited"
" with error status %d", what, (unsigned long)pid, st);
else
XL_LOG(ctx, XL_LOG_ERROR, "%s [%ld] unexpectedly"
" exited status zero", what, (unsigned long)pid);
} else if (WIFSIGNALED(status)) {
int sig = WTERMSIG(status);
const char *str = strsignal(sig);
const char *coredump = WCOREDUMP(status) ? " (core dumped)" : "";
if (str)
XL_LOG(ctx, XL_LOG_ERROR, "%s [%ld] died due to"
" fatal signal %s%s", what, (unsigned long)pid,
str, coredump);
else
XL_LOG(ctx, XL_LOG_ERROR, "%s [%ld] died due to unknown"
" fatal signal number %d%s", what, (unsigned long)pid,
sig, coredump);
} else {
XL_LOG(ctx, XL_LOG_ERROR, "%s [%ld] gave unknown"
" wait status 0x%x", what, (unsigned long)pid, status);
}
}
int libxl_spawn_spawn(struct libxl_ctx *ctx,
libxl_device_model_starting *starting,
const char *what,
void (*intermediate_hook)(struct libxl_ctx *ctx,
void *for_spawn,
pid_t innerchild))
{
pid_t child, got;
int status;
pid_t intermediate;
struct libxl_spawn_starting *for_spawn = starting->for_spawn;
if (for_spawn) {
for_spawn->what = libxl_sprintf(ctx, "%s", what);
if (!for_spawn->what) return ERROR_NOMEM;
}
intermediate = libxl_fork(ctx);
if (intermediate ==-1) {
if (for_spawn) free(for_spawn->what);
return ERROR_FAIL;
}
if (intermediate) {
/* parent */
if (for_spawn) for_spawn->intermediate = intermediate;
return 1;
}
/* we are now the intermediate process */
child = libxl_fork(ctx);
if (!child) return 0; /* caller runs child code */
if (child < 0) exit(255);
intermediate_hook(ctx, starting, child);
if (!for_spawn) _exit(0); /* just detach then */
got = call_waitpid(ctx->waitpid_instead, child, &status, 0);
assert(got == child);
libxl_report_child_exitstatus(ctx, what, child, status);
_exit(WIFEXITED(status) ? WEXITSTATUS(status) :
WIFSIGNALED(status) && WTERMSIG(status) < 127
? WTERMSIG(status)+128 : -1);
}
static void report_spawn_intermediate_status(struct libxl_ctx *ctx,
struct libxl_spawn_starting *for_spawn,
int status)
{
if (!WIFEXITED(status)) {
/* intermediate process did the logging itself if it exited */
char *intermediate_what = libxl_sprintf(ctx,
"%s intermediate process (startup monitor)",
for_spawn->what);
libxl_report_child_exitstatus(ctx, intermediate_what,
for_spawn->intermediate, status);
}
}
int libxl_spawn_detach(struct libxl_ctx *ctx,
struct libxl_spawn_starting *for_spawn)
{
int r, status;
pid_t got;
int rc = 0;
if (!for_spawn) return 0;
if (for_spawn->intermediate) {
r = kill(for_spawn->intermediate, SIGKILL);
if (r) {
XL_LOG_ERRNO(ctx, XL_LOG_ERROR,
"could not kill %s intermediate process [%ld]",
for_spawn->what,
(unsigned long)for_spawn->intermediate);
abort(); /* things are very wrong */
}
got = call_waitpid(ctx->waitpid_instead, for_spawn->intermediate, &status, 0);
assert(got == for_spawn->intermediate);
if (!(WIFSIGNALED(status) && WTERMSIG(status) == SIGKILL)) {
report_spawn_intermediate_status(ctx, for_spawn, status);
rc = ERROR_FAIL;
}
for_spawn->intermediate = 0;
}
free(for_spawn->what);
for_spawn->what = 0;
return rc;
}
int libxl_spawn_check(struct libxl_ctx *ctx, void *for_spawn_void)
{
struct libxl_spawn_starting *for_spawn = for_spawn_void;
pid_t got;
int status;
if (!for_spawn) return 0;
assert(for_spawn->intermediate);
got = call_waitpid(ctx->waitpid_instead, for_spawn->intermediate, &status, WNOHANG);
if (!got) return 0;
assert(got == for_spawn->intermediate);
report_spawn_intermediate_status(ctx, for_spawn, status);
for_spawn->intermediate = 0;
return ERROR_FAIL;
}
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