155 lines
3.3 KiB
C
155 lines
3.3 KiB
C
/* SPDX-License-Identifier: LGPL-2.1+ */
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#include <errno.h>
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#include <sys/stat.h>
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#include <unistd.h>
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#if HAVE_LINUX_MEMFD_H
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#include <linux/memfd.h>
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#endif
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#include <stdio.h>
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#include <sys/prctl.h>
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#include "alloc-util.h"
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#include "fd-util.h"
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#include "macro.h"
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#include "memfd-util.h"
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#include "missing_fcntl.h"
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#include "missing_mman.h"
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#include "missing_syscall.h"
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#include "string-util.h"
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#include "utf8.h"
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int memfd_new(const char *name) {
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_cleanup_free_ char *g = NULL;
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int fd;
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if (!name) {
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char pr[17] = {};
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/* If no name is specified we generate one. We include
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* a hint indicating our library implementation, and
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* add the thread name to it */
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assert_se(prctl(PR_GET_NAME, (unsigned long) pr) >= 0);
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if (isempty(pr))
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name = "sd";
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else {
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_cleanup_free_ char *e = NULL;
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e = utf8_escape_invalid(pr);
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if (!e)
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return -ENOMEM;
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g = strjoin("sd-", e);
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if (!g)
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return -ENOMEM;
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name = g;
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}
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}
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fd = memfd_create(name, MFD_ALLOW_SEALING | MFD_CLOEXEC);
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if (fd < 0)
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return -errno;
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return fd;
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}
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int memfd_map(int fd, uint64_t offset, size_t size, void **p) {
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void *q;
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int sealed;
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assert(fd >= 0);
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assert(size > 0);
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assert(p);
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sealed = memfd_get_sealed(fd);
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if (sealed < 0)
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return sealed;
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if (sealed)
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q = mmap(NULL, size, PROT_READ, MAP_PRIVATE, fd, offset);
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else
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q = mmap(NULL, size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, offset);
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if (q == MAP_FAILED)
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return -errno;
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*p = q;
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return 0;
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}
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int memfd_set_sealed(int fd) {
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int r;
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assert(fd >= 0);
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r = fcntl(fd, F_ADD_SEALS, F_SEAL_SHRINK | F_SEAL_GROW | F_SEAL_WRITE | F_SEAL_SEAL);
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if (r < 0)
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return -errno;
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return 0;
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}
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int memfd_get_sealed(int fd) {
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int r;
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assert(fd >= 0);
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r = fcntl(fd, F_GET_SEALS);
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if (r < 0)
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return -errno;
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return r == (F_SEAL_SHRINK | F_SEAL_GROW | F_SEAL_WRITE | F_SEAL_SEAL);
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}
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int memfd_get_size(int fd, uint64_t *sz) {
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struct stat stat;
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int r;
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assert(fd >= 0);
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assert(sz);
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r = fstat(fd, &stat);
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if (r < 0)
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return -errno;
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*sz = stat.st_size;
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return 0;
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}
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int memfd_set_size(int fd, uint64_t sz) {
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int r;
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assert(fd >= 0);
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r = ftruncate(fd, sz);
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if (r < 0)
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return -errno;
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return 0;
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}
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int memfd_new_and_map(const char *name, size_t sz, void **p) {
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_cleanup_close_ int fd = -1;
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int r;
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assert(sz > 0);
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assert(p);
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fd = memfd_new(name);
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if (fd < 0)
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return fd;
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r = memfd_set_size(fd, sz);
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if (r < 0)
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return r;
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r = memfd_map(fd, 0, sz, p);
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if (r < 0)
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return r;
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return TAKE_FD(fd);
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}
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