criu/util.c

#include <stdlib.h>
#include <stdio.h>
#include <stdarg.h>
#include <string.h>
#include <errno.h>
#include <unistd.h>
#include <stdbool.h>
#include <limits.h>
#include <signal.h>
#include <limits.h>
#include <unistd.h>
#include <errno.h>
#include <string.h>
#include <dirent.h>

#include <fcntl.h>

#include <sys/param.h>
#include <sys/types.h>
#include <sys/ptrace.h>
#include <sys/types.h>
#include <sys/time.h>
#include <sys/resource.h>
#include <sys/stat.h>
#include <sys/mman.h>
#include <sys/vfs.h>
#include <sys/ptrace.h>
#include <sys/user.h>
#include <sys/wait.h>
#include <sys/resource.h>
#include <sys/wait.h>

#include "compiler.h"
#include "types.h"
#include "list.h"
#include "util.h"

#include "crtools.h"

void pr_vma(unsigned int loglevel, const struct vma_area *vma_area)
{
	if (!vma_area)
		return;

	print_on_level(loglevel, "s: %16lx e: %16lx l: %8liK p: %8x f: %8x pg: %8lx "
		       "vf: %s st: %s spc: %-8s shmid: %8lx\n",
		       vma_area->vma.start, vma_area->vma.end,
		       KBYTES(vma_area_len(vma_area)),
		       vma_area->vma.prot,
		       vma_area->vma.flags,
		       vma_area->vma.pgoff,
		       vma_area->vm_file_fd < 0 ? "n" : "y",
		       !vma_area->vma.status ? "--" :
		       ((vma_area->vma.status & VMA_FILE_PRIVATE) ? "FP" :
			((vma_area->vma.status & VMA_FILE_SHARED) ? "FS" :
			 ((vma_area->vma.status & VMA_ANON_SHARED) ? "AS" :
			  ((vma_area->vma.status & VMA_ANON_PRIVATE) ? "AP" : "--")))),
		       !vma_area->vma.status ? "--" :
		       ((vma_area->vma.status & VMA_AREA_STACK) ? "stack" :
			((vma_area->vma.status & VMA_AREA_HEAP) ? "heap" :
			 ((vma_area->vma.status & VMA_AREA_VSYSCALL) ? "vsyscall" :
			  ((vma_area->vma.status & VMA_AREA_VDSO) ? "vdso" : "n")))),
			vma_area->vma.shmid);
}

int close_safe(int *fd)
{
	int ret = 0;
	if (*fd > -1) {
		ret = close(*fd);
		if (!ret)
			*fd = -1;
		else
			pr_perror("Unable to close fd %d", *fd);
	}

	return ret;
}

int reopen_fd_as_safe(int new_fd, int old_fd, bool allow_reuse_fd)
{
	int tmp;

	if (old_fd != new_fd) {

		if (!allow_reuse_fd) {
			if (fcntl(new_fd, F_GETFD) != -1 || errno != EBADF) {
				if (new_fd < 3) {
					/*
					 * Standard descriptors.
					 */
					pr_warn("fd %d already in use\n", new_fd);
				} else {
					pr_err("fd %d already in use\n", new_fd);
					return -1;
				}
			}
		}

		tmp = dup2(old_fd, new_fd);
		if (tmp < 0) {
			pr_perror("Dup %d -> %d failed", old_fd, new_fd);
			return tmp;
		}

		/* Just to have error message if failed */
		close_safe(&old_fd);
	}

	return 0;
}

int move_img_fd(int *img_fd, int want_fd)
{
	if (*img_fd == want_fd) {
		int tmp;

		tmp = dup(*img_fd);
		if (tmp < 0) {
			pr_perror("Can't dup file");
			return -1;
		}

		close(*img_fd);

		*img_fd = tmp;
	}

	return 0;
}

static int image_dir_fd = -1;

int open_image(int type, unsigned long flags, ...)
{
	char path[PATH_MAX];
	va_list args;
	int ret;

	va_start(args, flags);
	vsnprintf(path, PATH_MAX, fdset_template[type].fmt, args);
	va_end(args);

	if (flags & O_EXCL) {
		ret = unlinkat(image_dir_fd, path, 0);
		if (ret && errno != ENOENT) {
			pr_perror("Unable to unlink %s", path);
			goto err;
		}
	}

	ret = openat(image_dir_fd, path, flags, CR_FD_PERM);
	if (ret < 0) {
		pr_perror("Unable to open %s", path);
		goto err;
	}

	if (flags == O_RDONLY) {
		u32 magic;

		if (read_img(ret, &magic) < 0)
			goto err;
		if (magic != fdset_template[type].magic) {
			pr_err("Magic doesn't match for %s\n", path);
			goto err;
		}
	} else {
		if (write_img(ret, &fdset_template[type].magic))
			goto err;
	}

	return ret;
err:
	return -1;
}

int open_image_dir(void)
{
	int fd;

	image_dir_fd = get_service_fd(IMG_FD_OFF);
	if (image_dir_fd < 0) {
		pr_perror("Can't get image fd");
		return -1;
	}

	fd = open(".", O_RDONLY);
	if (fd < 0) {
		pr_perror("Can't open cwd");
		return -1;
	}

	pr_info("Image dir fd is %d\n", image_dir_fd);

	return reopen_fd_as(image_dir_fd, fd);
}

void close_image_dir(void)
{
	close(image_dir_fd);
	image_dir_fd = -1;
}

static pid_t open_proc_pid = 0;
static int open_proc_fd = -1;

int close_pid_proc(void)
{
	int ret = 0;

	if (open_proc_fd >= 0)
		ret = close(open_proc_fd);

	open_proc_fd = -1;
	open_proc_pid = 0;

	return ret;
}

inline int open_pid_proc(pid_t pid)
{
	char path[18];
	int fd;

	if (pid == open_proc_pid)
		return open_proc_fd;

	close_pid_proc();
	sprintf(path, "/proc/%d", pid);
	fd = open(path, O_RDONLY);
	if (fd < 0)
		pr_perror("Can't open %s", path);
	else {
		open_proc_fd = fd;
		open_proc_pid = pid;
	}

	return fd;
}

int do_open_proc(pid_t pid, int flags, const char *fmt, ...)
{
	char path[128];
	va_list args;
	int dirfd = open_pid_proc(pid);

	if (dirfd < 0)
		return -1;

	va_start(args, fmt);
	vsnprintf(path, sizeof(path), fmt, args);
	va_end(args);

	return openat(dirfd, path, flags);
}

int get_service_fd(int type)
{
	struct rlimit rlimit;

	/*
	 * Service FDs are thouse that most likely won't
	 * conflict with any 'real-life' ones
	 */

	if (getrlimit(RLIMIT_NOFILE, &rlimit)) {
		pr_perror("Can't get rlimit");
		return -1;
	}

	return rlimit.rlim_cur - type;
}