mirror of
https://github.com/troglobit/finit.git
synced 2026-10-03 14:33:12 +07:00
96 lines
2.8 KiB
C
96 lines
2.8 KiB
C
/* Portable clone3() wrapper with fallback to fork()
|
|
*
|
|
* Copyright (c) 2025 Joachim Wiberg <troglobit@gmail.com>
|
|
*
|
|
* Permission is hereby granted, free of charge, to any person obtaining a copy
|
|
* of this software and associated documentation files (the "Software"), to deal
|
|
* in the Software without restriction, including without limitation the rights
|
|
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
|
|
* copies of the Software, and to permit persons to whom the Software is
|
|
* furnished to do so, subject to the following conditions:
|
|
*
|
|
* The above copyright notice and this permission notice shall be included in
|
|
* all copies or substantial portions of the Software.
|
|
*
|
|
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
|
|
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
|
|
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
|
|
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
|
|
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
|
|
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
|
|
* THE SOFTWARE.
|
|
*/
|
|
|
|
#include "config.h"
|
|
|
|
#include <errno.h>
|
|
#include <sched.h>
|
|
#include <stddef.h>
|
|
#include <stdint.h>
|
|
#include <string.h>
|
|
#include <sys/syscall.h>
|
|
#include <sys/types.h>
|
|
#include <sys/wait.h>
|
|
#include <unistd.h>
|
|
|
|
#include "clone3.h"
|
|
#include "finit.h"
|
|
#include "log.h"
|
|
|
|
/* Clone3 flags from linux/sched.h */
|
|
#ifndef CLONE_INTO_CGROUP
|
|
#define CLONE_INTO_CGROUP 0x200000000ULL
|
|
#endif
|
|
|
|
/* Linux kernel struct clone_args for clone3() syscall */
|
|
struct clone3_args {
|
|
uint64_t flags; /* Flags bit mask */
|
|
uint64_t pidfd; /* File descriptor for PID */
|
|
uint64_t child_tid; /* Child TID */
|
|
uint64_t parent_tid; /* Parent TID */
|
|
uint64_t exit_signal; /* Signal to deliver on exit */
|
|
uint64_t stack; /* Stack address */
|
|
uint64_t stack_size; /* Stack size */
|
|
uint64_t tls; /* TLS descriptor */
|
|
uint64_t set_tid; /* Set PID */
|
|
uint64_t set_tid_size; /* Number of set_tid entries */
|
|
uint64_t cgroup; /* Cgroup file descriptor */
|
|
} __attribute__((aligned(8)));
|
|
|
|
#ifdef __NR_clone3
|
|
static int use_clone3 = 1;
|
|
#else
|
|
static int use_clone3 = 0;
|
|
#endif
|
|
|
|
int has_clone3(void)
|
|
{
|
|
return use_clone3 == 1;
|
|
}
|
|
|
|
pid_t call_clone3(uint64_t flags, int cgroup_fd)
|
|
{
|
|
struct clone3_args cl = {
|
|
.flags = flags,
|
|
.exit_signal = SIGCHLD,
|
|
};
|
|
pid_t pid;
|
|
|
|
if (!use_clone3)
|
|
goto fallback;
|
|
|
|
if (cgroup_fd >= 0) {
|
|
cl.flags |= CLONE_INTO_CGROUP;
|
|
cl.cgroup = cgroup_fd;
|
|
}
|
|
|
|
pid = syscall(__NR_clone3, &cl, sizeof(cl));
|
|
if (pid != -1)
|
|
return pid;
|
|
|
|
logit(LOG_WARNING, "clone3() failed, falling back to fork(): %s", strerror(errno));
|
|
use_clone3 = 0;
|
|
fallback:
|
|
return fork();
|
|
}
|