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/* SPDX-License-Identifier: LGPL-2.1-or-later */
#include <errno.h>
#include <sys/stat.h>
#include <unistd.h>
#if HAVE_LINUX_MEMFD_H
#include <linux/memfd.h>
#endif
#include <stdio.h>
#include <sys/prctl.h>
#include "alloc-util.h"
#include "errno-util.h"
#include "fd-util.h"
#include "macro.h"
#include "memfd-util.h"
#include "missing_fcntl.h"
#include "missing_mman.h"
#include "missing_syscall.h"
#include "string-util.h"
#include "utf8.h"
int memfd_create_wrapper(const char *name, unsigned mode) {
unsigned mode_compat;
int mfd;
mfd = RET_NERRNO(memfd_create(name, mode));
if (mfd != -EINVAL)
return mfd;
mode_compat = mode & ~(MFD_EXEC | MFD_NOEXEC_SEAL);
if (mode == mode_compat)
return mfd;
return RET_NERRNO(memfd_create(name, mode_compat));
}
int memfd_new(const char *name) {
_cleanup_free_ char *g = NULL;
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 = strjoin("sd-", e);
if (!g)
return -ENOMEM;
name = g;
}
}
return memfd_create_wrapper(name, MFD_ALLOW_SEALING | MFD_CLOEXEC | MFD_NOEXEC_SEAL);
}
int memfd_add_seals(int fd, unsigned int seals) {
assert(fd >= 0);
return RET_NERRNO(fcntl(fd, F_ADD_SEALS, seals));
}
int memfd_get_seals(int fd, unsigned int *ret_seals) {
int r;
assert(fd >= 0);
r = RET_NERRNO(fcntl(fd, F_GET_SEALS));
if (r < 0)
return r;
if (ret_seals)
*ret_seals = r;
return 0;
}
int memfd_map(int fd, uint64_t offset, size_t size, void **p) {
unsigned int seals;
void *q;
int r;
assert(fd >= 0);
assert(size > 0);
assert(p);
r = memfd_get_seals(fd, &seals);
if (r < 0)
return r;
if (seals & F_SEAL_WRITE)
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) {
return memfd_add_seals(fd, F_SEAL_SEAL | F_SEAL_SHRINK | F_SEAL_GROW | F_SEAL_WRITE);
}
int memfd_get_sealed(int fd) {
unsigned int seals;
int r;
r = memfd_get_seals(fd, &seals);
if (r < 0)
return r;
/* We ignore F_SEAL_EXEC here to support older kernels. */
return FLAGS_SET(seals, F_SEAL_SHRINK | F_SEAL_GROW | F_SEAL_WRITE);
}
int memfd_get_size(int fd, uint64_t *sz) {
struct stat stat;
assert(fd >= 0);
assert(sz);
if (fstat(fd, &stat) < 0)
return -errno;
*sz = stat.st_size;
return 0;
}
int memfd_set_size(int fd, uint64_t sz) {
assert(fd >= 0);
return RET_NERRNO(ftruncate(fd, sz));
}
int memfd_new_and_map(const char *name, size_t sz, void **p) {
_cleanup_close_ int fd = -EBADF;
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;
return TAKE_FD(fd);
}
int memfd_new_and_seal(const char *name, const void *data, size_t sz) {
_cleanup_close_ int fd = -EBADF;
ssize_t n;
off_t f;
int r;
assert(data || sz == 0);
fd = memfd_new(name);
if (fd < 0)
return fd;
if (sz > 0) {
n = write(fd, data, sz);
if (n < 0)
return -errno;
if ((size_t) n != sz)
return -EIO;
f = lseek(fd, 0, SEEK_SET);
if (f != 0)
return -errno;
}
r = memfd_set_sealed(fd);
if (r < 0)
return r;
return TAKE_FD(fd);
}
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