/*** This file is part of systemd. Copyright 2013 Lennart Poettering systemd 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; either version 2.1 of the License, or (at your option) any later version. systemd 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. You should have received a copy of the GNU Lesser General Public License along with systemd; If not, see <http://www.gnu.org/licenses/>. ***/ #include <errno.h> #include <fcntl.h> #include <sys/stat.h> #include <unistd.h> #ifdef HAVE_LINUX_MEMFD_H #include <linux/memfd.h> #endif #include <stdio.h> #include <sys/mman.h> #include <sys/prctl.h> #include "alloc-util.h" #include "fd-util.h" #include "macro.h" #include "memfd-util.h" #include "missing.h" #include "string-util.h" #include "utf8.h" int memfd_new(const char *name) { _cleanup_free_ char *g = NULL; int fd; if (!name) { char pr[17] = {}; /* If no name is specified we generate one. We include * a hint indicating our library implementation, and * add the thread name to it */ assert_se(prctl(PR_GET_NAME, (unsigned long) pr) >= 0); if (isempty(pr)) name = "sd"; else { _cleanup_free_ char *e = NULL; e = utf8_escape_invalid(pr); if (!e) return -ENOMEM; g = strappend("sd-", e); if (!g) return -ENOMEM; name = g; } } fd = memfd_create(name, MFD_ALLOW_SEALING | MFD_CLOEXEC); if (fd < 0) return -errno; return fd; } int memfd_map(int fd, uint64_t offset, size_t size, void **p) { void *q; int sealed; assert(fd >= 0); assert(size > 0); assert(p); sealed = memfd_get_sealed(fd); if (sealed < 0) return sealed; if (sealed) q = mmap(NULL, size, PROT_READ, MAP_PRIVATE, fd, offset); else q = mmap(NULL, size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, offset); if (q == MAP_FAILED) return -errno; *p = q; return 0; } int memfd_set_sealed(int fd) { int r; assert(fd >= 0); r = fcntl(fd, F_ADD_SEALS, F_SEAL_SHRINK | F_SEAL_GROW | F_SEAL_WRITE | F_SEAL_SEAL); if (r < 0) return -errno; return 0; } int memfd_get_sealed(int fd) { int r; assert(fd >= 0); r = fcntl(fd, F_GET_SEALS); if (r < 0) return -errno; return r == (F_SEAL_SHRINK | F_SEAL_GROW | F_SEAL_WRITE | F_SEAL_SEAL); } int memfd_get_size(int fd, uint64_t *sz) { struct stat stat; int r; assert(fd >= 0); assert(sz); r = fstat(fd, &stat); if (r < 0) return -errno; *sz = stat.st_size; return 0; } int memfd_set_size(int fd, uint64_t sz) { int r; assert(fd >= 0); r = ftruncate(fd, sz); if (r < 0) return -errno; return 0; } int memfd_new_and_map(const char *name, size_t sz, void **p) { _cleanup_close_ int fd = -1; int r; assert(sz > 0); assert(p); fd = memfd_new(name); if (fd < 0) return fd; r = memfd_set_size(fd, sz); if (r < 0) return r; r = memfd_map(fd, 0, sz, p); if (r < 0) return r; r = fd; fd = -1; return r; }