diff options
Diffstat (limited to 'src/libsystemd/sd-memfd.c')
| -rw-r--r-- | src/libsystemd/sd-memfd.c | 216 |
1 files changed, 216 insertions, 0 deletions
diff --git a/src/libsystemd/sd-memfd.c b/src/libsystemd/sd-memfd.c new file mode 100644 index 0000000000..cd95978ac2 --- /dev/null +++ b/src/libsystemd/sd-memfd.c @@ -0,0 +1,216 @@ +/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/ + +/*** + 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 <stdio.h> +#include <fcntl.h> +#include <sys/ioctl.h> +#include <sys/mman.h> + +#include "util.h" +#include "kdbus.h" + +#include "sd-memfd.h" + +struct sd_memfd { + int fd; + FILE *f; +}; + +_public_ int sd_memfd_new(sd_memfd **m) { + _cleanup_close_ int kdbus = -1; + sd_memfd *n; + int fd; + + assert_return(m, -EINVAL); + + kdbus = open("/dev/kdbus/control", O_RDWR|O_NOCTTY|O_CLOEXEC); + if (kdbus < 0) + return -errno; + + if (ioctl(kdbus, KDBUS_CMD_MEMFD_NEW, &fd) < 0) + return -errno; + + n = new0(struct sd_memfd, 1); + if (!n) + return -ENOMEM; + + n->fd = fd; + *m = n; + return 0; +} + +_public_ int sd_memfd_make(int fd, sd_memfd **m) { + sd_memfd *n; + uint64_t sz; + + assert_return(m, -EINVAL); + assert_return(fd >= 0, -EINVAL); + + /* Check if this is a valid memfd */ + if (ioctl(fd, KDBUS_CMD_MEMFD_SIZE_GET, &sz) < 0) + return -ENOTTY; + + n = new0(struct sd_memfd, 1); + if (!n) + return -ENOMEM; + + n->fd = fd; + *m = n; + + return 0; +} + +_public_ void sd_memfd_free(sd_memfd *m) { + if (!m) + return; + + if (m->f) + fclose(m->f); + else + close_nointr_nofail(m->fd); + + free(m); +} + +_public_ int sd_memfd_get_fd(sd_memfd *m) { + assert_return(m, -EINVAL); + + return m->fd; +} + +_public_ int sd_memfd_get_file(sd_memfd *m, FILE **f) { + assert_return(m, -EINVAL); + assert_return(f, -EINVAL); + + if (!m->f) { + m->f = fdopen(m->fd, "r+"); + if (!m->f) + return -errno; + } + + *f = m->f; + return 0; +} + +_public_ int sd_memfd_dup_fd(sd_memfd *m) { + int fd; + + assert_return(m, -EINVAL); + + fd = fcntl(m->fd, F_DUPFD_CLOEXEC, 3); + if (fd < 0) + return -errno; + + return fd; +} + +_public_ int sd_memfd_map(sd_memfd *m, uint64_t offset, size_t size, void **p) { + void *q; + int sealed; + + assert_return(m, -EINVAL); + assert_return(size > 0, -EINVAL); + assert_return(p, -EINVAL); + + sealed = sd_memfd_get_sealed(m); + if (sealed < 0) + return sealed; + + q = mmap(NULL, size, sealed ? PROT_READ : PROT_READ|PROT_WRITE, MAP_SHARED, m->fd, offset); + if (q == MAP_FAILED) + return -errno; + + *p = q; + return 0; +} + +_public_ int sd_memfd_set_sealed(sd_memfd *m, int b) { + int r; + + assert_return(m, -EINVAL); + + r = ioctl(m->fd, KDBUS_CMD_MEMFD_SEAL_SET, b); + if (r < 0) + return -errno; + + return 0; +} + +_public_ int sd_memfd_get_sealed(sd_memfd *m) { + int r, b; + + assert_return(m, -EINVAL); + + r = ioctl(m->fd, KDBUS_CMD_MEMFD_SEAL_GET, &b); + if (r < 0) + return -errno; + + return !!b; +} + +_public_ int sd_memfd_get_size(sd_memfd *m, uint64_t *sz) { + int r; + + assert_return(m, -EINVAL); + assert_return(sz, -EINVAL); + + r = ioctl(m->fd, KDBUS_CMD_MEMFD_SIZE_GET, sz); + if (r < 0) + return -errno; + + return r; +} + +_public_ int sd_memfd_set_size(sd_memfd *m, uint64_t sz) { + int r; + + assert_return(m, -EINVAL); + + r = ioctl(m->fd, KDBUS_CMD_MEMFD_SIZE_SET, &sz); + if (r < 0) + return -errno; + + return r; +} + +_public_ int sd_memfd_new_and_map(sd_memfd **m, size_t sz, void **p) { + sd_memfd *n; + int r; + + r = sd_memfd_new(&n); + if (r < 0) + return r; + + r = sd_memfd_set_size(n, sz); + if (r < 0) { + sd_memfd_free(n); + return r; + } + + r = sd_memfd_map(n, 0, sz, p); + if (r < 0) { + sd_memfd_free(n); + return r; + } + + *m = n; + return 0; +} |