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-rw-r--r--src/shared/memfd.c308
-rw-r--r--src/shared/memfd.h57
2 files changed, 365 insertions, 0 deletions
diff --git a/src/shared/memfd.c b/src/shared/memfd.c
new file mode 100644
index 0000000000..4dd70a2473
--- /dev/null
+++ b/src/shared/memfd.c
@@ -0,0 +1,308 @@
+/*-*- 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 <sys/prctl.h>
+
+#include "util.h"
+#include "bus-label.h"
+#include "missing.h"
+#include "memfd.h"
+
+#include "sd-bus.h"
+
+struct sd_memfd {
+ int fd;
+ FILE *f;
+};
+
+int sd_memfd_new(sd_memfd **m, const char *name) {
+
+ _cleanup_close_ int kdbus = -1;
+ _cleanup_free_ char *g = NULL;
+ sd_memfd *n;
+
+ assert_return(m, -EINVAL);
+
+ kdbus = open("/dev/kdbus/control", O_RDWR|O_NOCTTY|O_CLOEXEC);
+ if (kdbus < 0)
+ return -errno;
+
+ if (name) {
+ /* The kernel side is pretty picky about the character
+ * set here, let's do the usual bus escaping to deal
+ * with that. */
+
+ g = bus_label_escape(name);
+ if (!g)
+ return -ENOMEM;
+
+ name = g;
+
+ } else {
+ 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 = bus_label_escape(pr);
+ if (!e)
+ return -ENOMEM;
+
+ g = strappend("sd-", e);
+ if (!g)
+ return -ENOMEM;
+
+ name = g;
+ }
+ }
+
+ n = new0(struct sd_memfd, 1);
+ if (!n)
+ return -ENOMEM;
+
+ n->fd = memfd_create(name, 0, MFD_ALLOW_SEALING);
+ if (n->fd < 0) {
+ free(n);
+ return -errno;
+ }
+
+ *m = n;
+ return 0;
+}
+
+int sd_memfd_new_from_fd(sd_memfd **m, int fd) {
+ sd_memfd *n;
+
+ assert_return(m, -EINVAL);
+ assert_return(fd >= 0, -EINVAL);
+
+ /* Check if this is a sealable fd */
+ if (fcntl(fd, F_GET_SEALS) < 0)
+ return -ENOTTY;
+
+ n = new0(struct sd_memfd, 1);
+ if (!n)
+ return -ENOMEM;
+
+ n->fd = fd;
+ *m = n;
+
+ return 0;
+}
+
+void sd_memfd_free(sd_memfd *m) {
+ if (!m)
+ return;
+
+ if (m->f)
+ fclose(m->f);
+ else
+ safe_close(m->fd);
+
+ free(m);
+}
+
+int sd_memfd_get_fd(sd_memfd *m) {
+ assert_return(m, -EINVAL);
+
+ return m->fd;
+}
+
+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;
+}
+
+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;
+}
+
+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_PRIVATE, m->fd, offset);
+ if (q == MAP_FAILED)
+ return -errno;
+
+ *p = q;
+ return 0;
+}
+
+int sd_memfd_set_sealed(sd_memfd *m) {
+ int r;
+
+ assert_return(m, -EINVAL);
+
+ r = fcntl(m->fd, F_ADD_SEALS, F_SEAL_SHRINK | F_SEAL_GROW | F_SEAL_WRITE);
+ if (r < 0)
+ return -errno;
+
+ return 0;
+}
+
+int sd_memfd_get_sealed(sd_memfd *m) {
+ int r;
+
+ assert_return(m, -EINVAL);
+
+ r = fcntl(m->fd, F_GET_SEALS);
+ if (r < 0)
+ return -errno;
+
+ return (r & (F_SEAL_SHRINK | F_SEAL_GROW | F_SEAL_WRITE)) ==
+ (F_SEAL_SHRINK | F_SEAL_GROW | F_SEAL_WRITE);
+}
+
+int sd_memfd_get_size(sd_memfd *m, uint64_t *sz) {
+ int r;
+ struct stat stat;
+
+ assert_return(m, -EINVAL);
+ assert_return(sz, -EINVAL);
+
+ r = fstat(m->fd, &stat);
+ if (r < 0)
+ return -errno;
+
+ *sz = stat.st_size;
+ return r;
+}
+
+int sd_memfd_set_size(sd_memfd *m, uint64_t sz) {
+ int r;
+
+ assert_return(m, -EINVAL);
+
+ r = ftruncate(m->fd, sz);
+ if (r < 0)
+ return -errno;
+
+ return r;
+}
+
+int sd_memfd_new_and_map(sd_memfd **m, const char *name, size_t sz, void **p) {
+ sd_memfd *n;
+ int r;
+
+ r = sd_memfd_new(&n, name);
+ 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;
+}
+
+int sd_memfd_get_name(sd_memfd *m, char **name) {
+ char path[sizeof("/proc/self/fd/") + DECIMAL_STR_MAX(int)], buf[FILENAME_MAX+1], *e;
+ const char *delim, *end;
+ _cleanup_free_ char *n = NULL;
+ ssize_t k;
+
+ assert_return(m, -EINVAL);
+ assert_return(name, -EINVAL);
+
+ sprintf(path, "/proc/self/fd/%i", m->fd);
+
+ k = readlink(path, buf, sizeof(buf));
+ if (k < 0)
+ return -errno;
+
+ if ((size_t) k >= sizeof(buf))
+ return -E2BIG;
+
+ buf[k] = 0;
+
+ delim = strstr(buf, ":[");
+ if (!delim)
+ return -EIO;
+
+ delim = strchr(delim + 2, ':');
+ if (!delim)
+ return -EIO;
+
+ delim++;
+
+ end = strchr(delim, ']');
+ if (!end)
+ return -EIO;
+
+ n = strndup(delim, end - delim);
+ if (!n)
+ return -ENOMEM;
+
+ e = bus_label_unescape(n);
+ if (!e)
+ return -ENOMEM;
+
+ *name = e;
+
+ return 0;
+}
diff --git a/src/shared/memfd.h b/src/shared/memfd.h
new file mode 100644
index 0000000000..6de045c1d7
--- /dev/null
+++ b/src/shared/memfd.h
@@ -0,0 +1,57 @@
+/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
+
+#ifndef foosdmemfdhfoo
+#define foosdmemfdhfoo
+
+/***
+ 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 <inttypes.h>
+#include <sys/types.h>
+#include <stdio.h>
+
+#include "_sd-common.h"
+
+_SD_BEGIN_DECLARATIONS;
+
+typedef struct sd_memfd sd_memfd;
+
+int sd_memfd_new(sd_memfd **m, const char *name);
+int sd_memfd_new_from_fd(sd_memfd **m, int fd);
+int sd_memfd_new_and_map(sd_memfd **m, const char *name, size_t sz, void **p);
+
+void sd_memfd_free(sd_memfd *m);
+
+int sd_memfd_get_fd(sd_memfd *m);
+int sd_memfd_dup_fd(sd_memfd *n);
+int sd_memfd_get_file(sd_memfd *m, FILE **f);
+
+int sd_memfd_map(sd_memfd *m, uint64_t offset, size_t size, void **p);
+
+int sd_memfd_set_sealed(sd_memfd *m);
+int sd_memfd_get_sealed(sd_memfd *m);
+
+int sd_memfd_get_size(sd_memfd *m, uint64_t *sz);
+int sd_memfd_set_size(sd_memfd *m, uint64_t sz);
+
+int sd_memfd_get_name(sd_memfd *m, char **name);
+
+_SD_END_DECLARATIONS;
+
+#endif
generated by cgit v1.2.3-54-g00ecf (git 2.45.2) at 2024-11-16 07:52:55 +0000