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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-05-06 02:25:50 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-05-06 02:25:50 +0000 |
commit | 19f4f86bfed21c5326ed2acebe1163f3a83e832b (patch) | |
tree | d59b9989ce55ed23693e80974d94c856f1c2c8b1 /src/basic/memfd-util.c | |
parent | Initial commit. (diff) | |
download | systemd-19f4f86bfed21c5326ed2acebe1163f3a83e832b.tar.xz systemd-19f4f86bfed21c5326ed2acebe1163f3a83e832b.zip |
Adding upstream version 241.upstream/241upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'src/basic/memfd-util.c')
-rw-r--r-- | src/basic/memfd-util.c | 154 |
1 files changed, 154 insertions, 0 deletions
diff --git a/src/basic/memfd-util.c b/src/basic/memfd-util.c new file mode 100644 index 0000000..f88f0fc --- /dev/null +++ b/src/basic/memfd-util.c @@ -0,0 +1,154 @@ +/* SPDX-License-Identifier: LGPL-2.1+ */ + +#include <errno.h> +#include <fcntl.h> +#include <sys/stat.h> +#include <unistd.h> +#if 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; + + return TAKE_FD(fd); +} |