diff options
author | Luke Shumaker <lukeshu@sbcglobal.net> | 2016-06-02 13:16:04 -0400 |
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committer | Luke Shumaker <lukeshu@sbcglobal.net> | 2016-06-02 13:16:04 -0400 |
commit | fccd290a8373438c26ed4e4f8130db18eb9b3dfe (patch) | |
tree | 2f032e1b125aa88e456644de865e9f42fffa4150 /src/libbasic/memfd-util.c | |
parent | 6169d05b4a456e26a0197242464e3e2bca12a29d (diff) |
./move.sh
Diffstat (limited to 'src/libbasic/memfd-util.c')
-rw-r--r-- | src/libbasic/memfd-util.c | 174 |
1 files changed, 174 insertions, 0 deletions
diff --git a/src/libbasic/memfd-util.c b/src/libbasic/memfd-util.c new file mode 100644 index 0000000000..8c8cc78ebf --- /dev/null +++ b/src/libbasic/memfd-util.c @@ -0,0 +1,174 @@ +/*** + 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; +} |