#define _GNU_SOURCE #include #include #include #include #include #include #include #include #include #include #include #include static int syscall_clone (unsigned long flags, void *child_stack) { return (int) syscall (__NR_clone, flags, child_stack); } static char ** get_cmd_line_args (pid_t pid) { int fd; char path[PATH_MAX]; char *buffer; size_t allocated; size_t used = 0; int ret; int i, argc = 0; char **argv; sprintf (path, "/proc/%d/cmdline", pid); fd = open (path, O_RDONLY); if (fd < 0) return NULL; allocated = 512; buffer = malloc (allocated); if (buffer == NULL) return NULL; for (;;) { do ret = read (fd, buffer + used, allocated - used); while (ret < 0 && errno == EINTR); if (ret < 0) return NULL; if (ret == 0) break; used += ret; if (allocated == used) { allocated += 512; buffer = realloc (buffer, allocated); if (buffer == NULL) return NULL; } } close (fd); for (i = 0; i < used; i++) if (buffer[i] == '\0') argc++; argv = malloc (sizeof (char *) * (argc + 1)); if (argv == NULL) return NULL; argc = 0; argv[argc++] = buffer; for (i = 0; i < used - 1; i++) if (buffer[i] == '\0') argv[argc++] = buffer + i + 1; argv[argc] = NULL; return argv; } int reexec_in_user_namespace(int ready) { int ret; pid_t pid; char b; pid_t ppid = getpid (); char **argv; pid = syscall_clone (CLONE_NEWUSER|SIGCHLD, NULL); if (pid) return pid; argv = get_cmd_line_args (ppid); setenv ("_LIBPOD_USERNS_CONFIGURED", "init", 1); do ret = read (ready, &b, 1) < 0; while (ret < 0 && errno == EINTR); if (ret < 0) _exit (1); close (ready); execv (argv[0], argv); _exit (1); } int reexec_in_user_namespace_wait (int pid) { pid_t p; int status; do p = waitpid (pid, &status, 0); while (p < 0 && errno == EINTR); if (p < 0) return -1; if (WIFEXITED (status)) return WEXITSTATUS (status); if (WIFSIGNALED (status)) return 128 + WTERMSIG (status); return -1; }