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/* PipeWire */
/* SPDX-FileCopyrightText: Copyright © 2018 Wim Taymans */
/* SPDX-License-Identifier: MIT */
#ifndef FLATPAK_UTILS_H
#define FLATPAK_UTILS_H
#define HAVE_GLIB2
#include <stdio.h>
#include <string.h>
#include <fcntl.h>
#include <sys/mman.h>
#include <sys/stat.h>
#ifdef HAVE_SYS_VFS_H
#include <sys/vfs.h>
#endif
#ifdef HAVE_GLIB2
#include <glib.h>
#endif
#include <spa/utils/cleanup.h>
#include <spa/utils/result.h>
#include <pipewire/log.h>
static int pw_check_flatpak_parse_metadata(const char *buf, size_t size, char **app_id, char **instance_id, char **devices)
{
#ifdef HAVE_GLIB2
/*
* See flatpak-metadata(5)
*
* The .flatpak-info file is in GLib key_file .ini format.
*/
g_autoptr(GKeyFile) metadata = NULL;
char *s;
metadata = g_key_file_new();
if (!g_key_file_load_from_data(metadata, buf, size, G_KEY_FILE_NONE, NULL))
return -EINVAL;
if (app_id) {
s = g_key_file_get_value(metadata, "Application", "name", NULL);
*app_id = s ? strdup(s) : NULL;
g_free(s);
}
if (devices) {
s = g_key_file_get_value(metadata, "Context", "devices", NULL);
*devices = s ? strdup(s) : NULL;
g_free(s);
}
if (instance_id) {
s = g_key_file_get_value(metadata, "Instance", "instance-id", NULL);
*instance_id = s ? strdup(s) : NULL;
g_free(s);
}
return 0;
#else
return -ENOTSUP;
#endif
}
static int pw_check_flatpak(pid_t pid, char **app_id, char **instance_id, char **devices)
{
#if defined(__linux__)
char root_path[2048];
struct stat stat_buf;
int res;
if (app_id)
*app_id = NULL;
if (instance_id)
*instance_id = NULL;
if (devices)
*devices = NULL;
snprintf(root_path, sizeof(root_path), "/proc/%d/root", (int)pid);
spa_autoclose int root_fd = openat(AT_FDCWD, root_path, O_RDONLY | O_NONBLOCK | O_DIRECTORY | O_CLOEXEC | O_NOCTTY);
if (root_fd < 0) {
res = -errno;
pw_log_info("failed to open \"%s\": %s", root_path, spa_strerror(res));
if (res == -EACCES) {
/* If we can't access the root filesystem, consider not sandboxed.
* This should not happen but for now it is a workaround for selinux
* where we can't access the gnome-shell root when it connects for
* screen sharing.
*/
return 0;
}
/* Not able to open the root dir shouldn't happen. Probably the app died and
* we're failing due to /proc/$pid not existing. In that case fail instead
* of treating this as privileged. */
return res;
}
spa_autoclose int info_fd = openat(root_fd, ".flatpak-info", O_RDONLY | O_CLOEXEC | O_NOCTTY);
if (info_fd < 0) {
if (errno == ENOENT) {
pw_log_debug("no .flatpak-info, client on the host");
/* No file => on the host */
return 0;
}
res = -errno;
pw_log_error("error opening .flatpak-info: %m");
return res;
}
if (fstat (info_fd, &stat_buf) != 0 || !S_ISREG (stat_buf.st_mode)) {
/* Some weird fd => failure, assume sandboxed */
pw_log_error("error fstat .flatpak-info: %m");
} else if (app_id || instance_id || devices) {
/* Parse the application ID if needed */
const size_t size = stat_buf.st_size;
if (size > 0) {
void *buf = mmap(NULL, size, PROT_READ, MAP_PRIVATE, info_fd, 0);
if (buf != MAP_FAILED) {
res = pw_check_flatpak_parse_metadata(buf, size, app_id, instance_id, devices);
munmap(buf, size);
} else {
res = -errno;
}
} else {
res = -EINVAL;
}
if (res == -EINVAL)
pw_log_error("PID %d .flatpak-info file is malformed",
(int)pid);
else if (res < 0)
pw_log_error("PID %d .flatpak-info parsing failed: %s",
(int)pid, spa_strerror(res));
}
return 1;
#else
return 0;
#endif
}
#endif /* FLATPAK_UTILS_H */
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