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97870c34b4
Convert files to use SPDX header. All files are licensed under the GPLv2. Signed-off-by: Alex Dewar <alex.dewar@gmx.co.uk> Signed-off-by: Richard Weinberger <richard@nod.at>
211 lines
4.2 KiB
C
211 lines
4.2 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Copyright (C) 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
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*/
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#include <stdio.h>
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#include <stddef.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include <errno.h>
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#include <fcntl.h>
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#include <string.h>
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#include <sys/stat.h>
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#include <sys/mman.h>
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#include <sys/vfs.h>
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#include <linux/magic.h>
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#include <init.h>
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#include <os.h>
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/* Set by make_tempfile() during early boot. */
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static char *tempdir = NULL;
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/* Check if dir is on tmpfs. Return 0 if yes, -1 if no or error. */
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static int __init check_tmpfs(const char *dir)
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{
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struct statfs st;
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os_info("Checking if %s is on tmpfs...", dir);
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if (statfs(dir, &st) < 0) {
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os_info("%s\n", strerror(errno));
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} else if (st.f_type != TMPFS_MAGIC) {
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os_info("no\n");
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} else {
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os_info("OK\n");
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return 0;
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}
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return -1;
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}
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/*
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* Choose the tempdir to use. We want something on tmpfs so that our memory is
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* not subject to the host's vm.dirty_ratio. If a tempdir is specified in the
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* environment, we use that even if it's not on tmpfs, but we warn the user.
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* Otherwise, we try common tmpfs locations, and if no tmpfs directory is found
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* then we fall back to /tmp.
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*/
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static char * __init choose_tempdir(void)
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{
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static const char * const vars[] = {
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"TMPDIR",
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"TMP",
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"TEMP",
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NULL
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};
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static const char fallback_dir[] = "/tmp";
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static const char * const tmpfs_dirs[] = {
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"/dev/shm",
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fallback_dir,
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NULL
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};
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int i;
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const char *dir;
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os_info("Checking environment variables for a tempdir...");
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for (i = 0; vars[i]; i++) {
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dir = getenv(vars[i]);
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if ((dir != NULL) && (*dir != '\0')) {
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os_info("%s\n", dir);
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if (check_tmpfs(dir) >= 0)
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goto done;
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else
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goto warn;
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}
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}
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os_info("none found\n");
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for (i = 0; tmpfs_dirs[i]; i++) {
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dir = tmpfs_dirs[i];
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if (check_tmpfs(dir) >= 0)
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goto done;
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}
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dir = fallback_dir;
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warn:
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os_warn("Warning: tempdir %s is not on tmpfs\n", dir);
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done:
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/* Make a copy since getenv results may not remain valid forever. */
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return strdup(dir);
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}
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/*
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* Create an unlinked tempfile in a suitable tempdir. template must be the
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* basename part of the template with a leading '/'.
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*/
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static int __init make_tempfile(const char *template)
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{
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char *tempname;
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int fd;
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if (tempdir == NULL) {
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tempdir = choose_tempdir();
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if (tempdir == NULL) {
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os_warn("Failed to choose tempdir: %s\n",
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strerror(errno));
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return -1;
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}
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}
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#ifdef O_TMPFILE
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fd = open(tempdir, O_CLOEXEC | O_RDWR | O_EXCL | O_TMPFILE, 0700);
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/*
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* If the running system does not support O_TMPFILE flag then retry
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* without it.
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*/
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if (fd != -1 || (errno != EINVAL && errno != EISDIR &&
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errno != EOPNOTSUPP))
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return fd;
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#endif
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tempname = malloc(strlen(tempdir) + strlen(template) + 1);
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if (tempname == NULL)
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return -1;
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strcpy(tempname, tempdir);
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strcat(tempname, template);
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fd = mkstemp(tempname);
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if (fd < 0) {
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os_warn("open - cannot create %s: %s\n", tempname,
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strerror(errno));
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goto out;
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}
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if (unlink(tempname) < 0) {
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perror("unlink");
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goto close;
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}
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free(tempname);
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return fd;
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close:
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close(fd);
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out:
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free(tempname);
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return -1;
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}
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#define TEMPNAME_TEMPLATE "/vm_file-XXXXXX"
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static int __init create_tmp_file(unsigned long long len)
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{
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int fd, err;
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char zero;
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fd = make_tempfile(TEMPNAME_TEMPLATE);
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if (fd < 0)
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exit(1);
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/*
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* Seek to len - 1 because writing a character there will
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* increase the file size by one byte, to the desired length.
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*/
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if (lseek64(fd, len - 1, SEEK_SET) < 0) {
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perror("lseek64");
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exit(1);
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}
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zero = 0;
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err = write(fd, &zero, 1);
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if (err != 1) {
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perror("write");
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exit(1);
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}
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return fd;
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}
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int __init create_mem_file(unsigned long long len)
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{
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int err, fd;
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fd = create_tmp_file(len);
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err = os_set_exec_close(fd);
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if (err < 0) {
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errno = -err;
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perror("exec_close");
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}
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return fd;
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}
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void __init check_tmpexec(void)
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{
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void *addr;
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int err, fd = create_tmp_file(UM_KERN_PAGE_SIZE);
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addr = mmap(NULL, UM_KERN_PAGE_SIZE,
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PROT_READ | PROT_WRITE | PROT_EXEC, MAP_PRIVATE, fd, 0);
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os_info("Checking PROT_EXEC mmap in %s...", tempdir);
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if (addr == MAP_FAILED) {
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err = errno;
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os_warn("%s\n", strerror(err));
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close(fd);
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if (err == EPERM)
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os_warn("%s must be not mounted noexec\n", tempdir);
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exit(1);
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}
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os_info("OK\n");
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munmap(addr, UM_KERN_PAGE_SIZE);
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close(fd);
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}
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