69dcb7e771
providing compiled-in static environment data that is used instead of any data passed in from a boot loader. Previously 'env' worked only on i386 and arm xscale systems, because it required the MD startup code to examine the global envmode variable and decide whether to use static_env or an environment obtained from the boot loader, and set the global kern_envp accordingly. Most startup code wasn't doing so. Making things even more complex, some mips startup code uses an alternate scheme that involves calling init_static_kenv() to pass an empty buffer and its size, then uses a series of kern_setenv() calls to populate that buffer. Now all MD startup code calls init_static_kenv(), and that routine provides a single point where envmode is checked and the decision is made whether to use the compiled-in static_kenv or the values provided by the MD code. The routine also continues to serve its original purpose for mips; if a non-zero buffer size is passed the routine installs the empty buffer ready to accept kern_setenv() values. Now if the size is zero, the provided buffer full of existing env data is installed. A NULL pointer can be passed if the boot loader provides no env data; this allows the static env to be installed if envmode is set to do so. Most of the work here is a near-mechanical change to call the init function instead of directly setting kern_envp. A notable exception is in xen/pv.c; that code was originally installing a buffer full of preformatted env data along with its non-zero size (like mips code does), which would have allowed kern_setenv() calls to wipe out the preformatted data. Now it passes a zero for the size so that the buffer of data it installs is treated as non-writeable.
656 lines
14 KiB
C
656 lines
14 KiB
C
/*-
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* Copyright (c) 1998 Michael Smith
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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/*
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* The unified bootloader passes us a pointer to a preserved copy of
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* bootstrap/kernel environment variables. We convert them to a
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* dynamic array of strings later when the VM subsystem is up.
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*
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* We make these available through the kenv(2) syscall for userland
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* and through kern_getenv()/freeenv() kern_setenv() kern_unsetenv() testenv() for
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* the kernel.
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include <sys/types.h>
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#include <sys/param.h>
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#include <sys/proc.h>
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#include <sys/queue.h>
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#include <sys/lock.h>
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#include <sys/malloc.h>
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#include <sys/mutex.h>
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#include <sys/priv.h>
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#include <sys/kernel.h>
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#include <sys/systm.h>
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#include <sys/sysent.h>
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#include <sys/sysproto.h>
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#include <sys/libkern.h>
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#include <sys/kenv.h>
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#include <security/mac/mac_framework.h>
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static MALLOC_DEFINE(M_KENV, "kenv", "kernel environment");
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#define KENV_SIZE 512 /* Maximum number of environment strings */
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/* pointer to the static environment */
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char *kern_envp;
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static int env_len;
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static int env_pos;
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static char *kernenv_next(char *);
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/* dynamic environment variables */
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char **kenvp;
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struct mtx kenv_lock;
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/*
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* No need to protect this with a mutex since SYSINITS are single threaded.
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*/
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int dynamic_kenv = 0;
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#define KENV_CHECK if (!dynamic_kenv) \
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panic("%s: called before SI_SUB_KMEM", __func__)
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int
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sys_kenv(td, uap)
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struct thread *td;
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struct kenv_args /* {
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int what;
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const char *name;
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char *value;
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int len;
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} */ *uap;
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{
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char *name, *value, *buffer = NULL;
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size_t len, done, needed, buflen;
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int error, i;
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KASSERT(dynamic_kenv, ("kenv: dynamic_kenv = 0"));
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error = 0;
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if (uap->what == KENV_DUMP) {
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#ifdef MAC
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error = mac_kenv_check_dump(td->td_ucred);
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if (error)
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return (error);
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#endif
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done = needed = 0;
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buflen = uap->len;
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if (buflen > KENV_SIZE * (KENV_MNAMELEN + KENV_MVALLEN + 2))
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buflen = KENV_SIZE * (KENV_MNAMELEN +
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KENV_MVALLEN + 2);
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if (uap->len > 0 && uap->value != NULL)
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buffer = malloc(buflen, M_TEMP, M_WAITOK|M_ZERO);
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mtx_lock(&kenv_lock);
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for (i = 0; kenvp[i] != NULL; i++) {
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len = strlen(kenvp[i]) + 1;
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needed += len;
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len = min(len, buflen - done);
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/*
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* If called with a NULL or insufficiently large
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* buffer, just keep computing the required size.
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*/
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if (uap->value != NULL && buffer != NULL && len > 0) {
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bcopy(kenvp[i], buffer + done, len);
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done += len;
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}
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}
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mtx_unlock(&kenv_lock);
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if (buffer != NULL) {
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error = copyout(buffer, uap->value, done);
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free(buffer, M_TEMP);
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}
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td->td_retval[0] = ((done == needed) ? 0 : needed);
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return (error);
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}
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switch (uap->what) {
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case KENV_SET:
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error = priv_check(td, PRIV_KENV_SET);
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if (error)
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return (error);
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break;
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case KENV_UNSET:
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error = priv_check(td, PRIV_KENV_UNSET);
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if (error)
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return (error);
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break;
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}
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name = malloc(KENV_MNAMELEN + 1, M_TEMP, M_WAITOK);
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error = copyinstr(uap->name, name, KENV_MNAMELEN + 1, NULL);
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if (error)
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goto done;
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switch (uap->what) {
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case KENV_GET:
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#ifdef MAC
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error = mac_kenv_check_get(td->td_ucred, name);
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if (error)
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goto done;
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#endif
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value = kern_getenv(name);
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if (value == NULL) {
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error = ENOENT;
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goto done;
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}
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len = strlen(value) + 1;
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if (len > uap->len)
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len = uap->len;
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error = copyout(value, uap->value, len);
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freeenv(value);
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if (error)
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goto done;
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td->td_retval[0] = len;
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break;
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case KENV_SET:
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len = uap->len;
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if (len < 1) {
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error = EINVAL;
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goto done;
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}
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if (len > KENV_MVALLEN + 1)
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len = KENV_MVALLEN + 1;
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value = malloc(len, M_TEMP, M_WAITOK);
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error = copyinstr(uap->value, value, len, NULL);
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if (error) {
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free(value, M_TEMP);
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goto done;
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}
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#ifdef MAC
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error = mac_kenv_check_set(td->td_ucred, name, value);
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if (error == 0)
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#endif
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kern_setenv(name, value);
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free(value, M_TEMP);
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break;
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case KENV_UNSET:
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#ifdef MAC
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error = mac_kenv_check_unset(td->td_ucred, name);
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if (error)
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goto done;
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#endif
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error = kern_unsetenv(name);
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if (error)
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error = ENOENT;
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break;
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default:
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error = EINVAL;
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break;
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}
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done:
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free(name, M_TEMP);
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return (error);
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}
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/*
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* Populate the initial kernel environment.
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*
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* This is called very early in MD startup, either to provide a copy of the
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* environment obtained from a boot loader, or to provide an empty buffer into
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* which MD code can store an initial environment using kern_setenv() calls.
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*
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* If the global envmode is 1, the environment is initialized from the global
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* static_env[], regardless of the arguments passed. This implements the env
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* keyword described in config(5). In this case env_pos is set to env_len,
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* causing kern_setenv() to return -1 (if len > 0) or panic (if len == 0) until
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* the dynamic environment is available. The envmode and static_env variables
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* are defined in env.c which is generated by config(8).
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*
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* If len is non-zero, the caller is providing an empty buffer. The caller will
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* subsequently use kern_setenv() to add up to len bytes of initial environment
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* before the dynamic environment is available.
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*
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* If len is zero, the caller is providing a pre-loaded buffer containing
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* environment strings. Additional strings cannot be added until the dynamic
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* environment is available. The memory pointed to must remain stable at least
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* until sysinit runs init_dynamic_kenv(). If no initial environment is
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* available from the boot loader, passing a NULL pointer allows the static_env
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* to be installed if it is configured.
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*/
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void
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init_static_kenv(char *buf, size_t len)
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{
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if (envmode == 1) {
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kern_envp = static_env;
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env_len = len;
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env_pos = len;
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} else {
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kern_envp = buf;
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env_len = len;
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env_pos = 0;
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}
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}
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/*
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* Setup the dynamic kernel environment.
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*/
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static void
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init_dynamic_kenv(void *data __unused)
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{
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char *cp, *cpnext;
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size_t len;
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int i;
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kenvp = malloc((KENV_SIZE + 1) * sizeof(char *), M_KENV,
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M_WAITOK | M_ZERO);
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i = 0;
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if (kern_envp && *kern_envp != '\0') {
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for (cp = kern_envp; cp != NULL; cp = cpnext) {
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cpnext = kernenv_next(cp);
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len = strlen(cp) + 1;
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if (len > KENV_MNAMELEN + 1 + KENV_MVALLEN + 1) {
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printf(
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"WARNING: too long kenv string, ignoring %s\n",
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cp);
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continue;
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}
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if (i < KENV_SIZE) {
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kenvp[i] = malloc(len, M_KENV, M_WAITOK);
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strcpy(kenvp[i++], cp);
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memset(cp, 0, strlen(cp));
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} else
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printf(
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"WARNING: too many kenv strings, ignoring %s\n",
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cp);
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}
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}
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kenvp[i] = NULL;
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mtx_init(&kenv_lock, "kernel environment", NULL, MTX_DEF);
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dynamic_kenv = 1;
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}
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SYSINIT(kenv, SI_SUB_KMEM, SI_ORDER_ANY, init_dynamic_kenv, NULL);
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void
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freeenv(char *env)
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{
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if (dynamic_kenv && env != NULL) {
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memset(env, 0, strlen(env));
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free(env, M_KENV);
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}
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}
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/*
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* Internal functions for string lookup.
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*/
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static char *
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_getenv_dynamic(const char *name, int *idx)
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{
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char *cp;
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int len, i;
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mtx_assert(&kenv_lock, MA_OWNED);
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len = strlen(name);
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for (cp = kenvp[0], i = 0; cp != NULL; cp = kenvp[++i]) {
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if ((strncmp(cp, name, len) == 0) &&
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(cp[len] == '=')) {
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if (idx != NULL)
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*idx = i;
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return (cp + len + 1);
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}
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}
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return (NULL);
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}
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static char *
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_getenv_static(const char *name)
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{
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char *cp, *ep;
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int len;
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for (cp = kern_envp; cp != NULL; cp = kernenv_next(cp)) {
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for (ep = cp; (*ep != '=') && (*ep != 0); ep++)
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;
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if (*ep != '=')
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continue;
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len = ep - cp;
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ep++;
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if (!strncmp(name, cp, len) && name[len] == 0)
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return (ep);
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}
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return (NULL);
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}
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/*
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* Look up an environment variable by name.
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* Return a pointer to the string if found.
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* The pointer has to be freed with freeenv()
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* after use.
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*/
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char *
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kern_getenv(const char *name)
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{
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char buf[KENV_MNAMELEN + 1 + KENV_MVALLEN + 1];
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char *ret;
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if (dynamic_kenv) {
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if (getenv_string(name, buf, sizeof(buf))) {
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ret = strdup(buf, M_KENV);
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} else {
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ret = NULL;
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WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL,
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"getenv");
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}
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} else
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ret = _getenv_static(name);
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return (ret);
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}
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/*
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* Test if an environment variable is defined.
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*/
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int
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testenv(const char *name)
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{
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char *cp;
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if (dynamic_kenv) {
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mtx_lock(&kenv_lock);
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cp = _getenv_dynamic(name, NULL);
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mtx_unlock(&kenv_lock);
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} else
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cp = _getenv_static(name);
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if (cp != NULL)
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return (1);
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return (0);
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}
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static int
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setenv_static(const char *name, const char *value)
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{
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int len;
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if (env_pos >= env_len)
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return (-1);
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/* Check space for x=y and two nuls */
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len = strlen(name) + strlen(value);
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if (len + 3 < env_len - env_pos) {
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len = sprintf(&kern_envp[env_pos], "%s=%s", name, value);
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env_pos += len+1;
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kern_envp[env_pos] = '\0';
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return (0);
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} else
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return (-1);
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}
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/*
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* Set an environment variable by name.
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*/
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int
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kern_setenv(const char *name, const char *value)
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{
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char *buf, *cp, *oldenv;
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int namelen, vallen, i;
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if (dynamic_kenv == 0 && env_len > 0)
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return (setenv_static(name, value));
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KENV_CHECK;
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namelen = strlen(name) + 1;
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if (namelen > KENV_MNAMELEN + 1)
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return (-1);
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vallen = strlen(value) + 1;
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if (vallen > KENV_MVALLEN + 1)
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return (-1);
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buf = malloc(namelen + vallen, M_KENV, M_WAITOK);
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sprintf(buf, "%s=%s", name, value);
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mtx_lock(&kenv_lock);
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cp = _getenv_dynamic(name, &i);
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if (cp != NULL) {
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oldenv = kenvp[i];
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kenvp[i] = buf;
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mtx_unlock(&kenv_lock);
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free(oldenv, M_KENV);
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} else {
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/* We add the option if it wasn't found */
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for (i = 0; (cp = kenvp[i]) != NULL; i++)
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;
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/* Bounds checking */
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if (i < 0 || i >= KENV_SIZE) {
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free(buf, M_KENV);
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mtx_unlock(&kenv_lock);
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return (-1);
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}
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kenvp[i] = buf;
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kenvp[i + 1] = NULL;
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mtx_unlock(&kenv_lock);
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}
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return (0);
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}
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/*
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* Unset an environment variable string.
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*/
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int
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kern_unsetenv(const char *name)
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{
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char *cp, *oldenv;
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int i, j;
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KENV_CHECK;
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mtx_lock(&kenv_lock);
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cp = _getenv_dynamic(name, &i);
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if (cp != NULL) {
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oldenv = kenvp[i];
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for (j = i + 1; kenvp[j] != NULL; j++)
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kenvp[i++] = kenvp[j];
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kenvp[i] = NULL;
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mtx_unlock(&kenv_lock);
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memset(oldenv, 0, strlen(oldenv));
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free(oldenv, M_KENV);
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return (0);
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}
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mtx_unlock(&kenv_lock);
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return (-1);
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}
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/*
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* Return a string value from an environment variable.
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*/
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int
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getenv_string(const char *name, char *data, int size)
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{
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char *cp;
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if (dynamic_kenv) {
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mtx_lock(&kenv_lock);
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cp = _getenv_dynamic(name, NULL);
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if (cp != NULL)
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strlcpy(data, cp, size);
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mtx_unlock(&kenv_lock);
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} else {
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cp = _getenv_static(name);
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if (cp != NULL)
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strlcpy(data, cp, size);
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}
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return (cp != NULL);
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}
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/*
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* Return an integer value from an environment variable.
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*/
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int
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getenv_int(const char *name, int *data)
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{
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quad_t tmp;
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int rval;
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rval = getenv_quad(name, &tmp);
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if (rval)
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*data = (int) tmp;
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return (rval);
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}
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/*
|
|
* Return an unsigned integer value from an environment variable.
|
|
*/
|
|
int
|
|
getenv_uint(const char *name, unsigned int *data)
|
|
{
|
|
quad_t tmp;
|
|
int rval;
|
|
|
|
rval = getenv_quad(name, &tmp);
|
|
if (rval)
|
|
*data = (unsigned int) tmp;
|
|
return (rval);
|
|
}
|
|
|
|
/*
|
|
* Return a long value from an environment variable.
|
|
*/
|
|
int
|
|
getenv_long(const char *name, long *data)
|
|
{
|
|
quad_t tmp;
|
|
int rval;
|
|
|
|
rval = getenv_quad(name, &tmp);
|
|
if (rval)
|
|
*data = (long) tmp;
|
|
return (rval);
|
|
}
|
|
|
|
/*
|
|
* Return an unsigned long value from an environment variable.
|
|
*/
|
|
int
|
|
getenv_ulong(const char *name, unsigned long *data)
|
|
{
|
|
quad_t tmp;
|
|
int rval;
|
|
|
|
rval = getenv_quad(name, &tmp);
|
|
if (rval)
|
|
*data = (unsigned long) tmp;
|
|
return (rval);
|
|
}
|
|
|
|
/*
|
|
* Return a quad_t value from an environment variable.
|
|
*/
|
|
int
|
|
getenv_quad(const char *name, quad_t *data)
|
|
{
|
|
char value[KENV_MNAMELEN + 1 + KENV_MVALLEN + 1];
|
|
char *vtp;
|
|
quad_t iv;
|
|
|
|
if (!getenv_string(name, value, sizeof(value)))
|
|
return (0);
|
|
iv = strtoq(value, &vtp, 0);
|
|
if (vtp == value || (vtp[0] != '\0' && vtp[1] != '\0'))
|
|
return (0);
|
|
switch (vtp[0]) {
|
|
case 't': case 'T':
|
|
iv *= 1024;
|
|
case 'g': case 'G':
|
|
iv *= 1024;
|
|
case 'm': case 'M':
|
|
iv *= 1024;
|
|
case 'k': case 'K':
|
|
iv *= 1024;
|
|
case '\0':
|
|
break;
|
|
default:
|
|
return (0);
|
|
}
|
|
*data = iv;
|
|
return (1);
|
|
}
|
|
|
|
/*
|
|
* Find the next entry after the one which (cp) falls within, return a
|
|
* pointer to its start or NULL if there are no more.
|
|
*/
|
|
static char *
|
|
kernenv_next(char *cp)
|
|
{
|
|
|
|
if (cp != NULL) {
|
|
while (*cp != 0)
|
|
cp++;
|
|
cp++;
|
|
if (*cp == 0)
|
|
cp = NULL;
|
|
}
|
|
return (cp);
|
|
}
|
|
|
|
void
|
|
tunable_int_init(void *data)
|
|
{
|
|
struct tunable_int *d = (struct tunable_int *)data;
|
|
|
|
TUNABLE_INT_FETCH(d->path, d->var);
|
|
}
|
|
|
|
void
|
|
tunable_long_init(void *data)
|
|
{
|
|
struct tunable_long *d = (struct tunable_long *)data;
|
|
|
|
TUNABLE_LONG_FETCH(d->path, d->var);
|
|
}
|
|
|
|
void
|
|
tunable_ulong_init(void *data)
|
|
{
|
|
struct tunable_ulong *d = (struct tunable_ulong *)data;
|
|
|
|
TUNABLE_ULONG_FETCH(d->path, d->var);
|
|
}
|
|
|
|
void
|
|
tunable_quad_init(void *data)
|
|
{
|
|
struct tunable_quad *d = (struct tunable_quad *)data;
|
|
|
|
TUNABLE_QUAD_FETCH(d->path, d->var);
|
|
}
|
|
|
|
void
|
|
tunable_str_init(void *data)
|
|
{
|
|
struct tunable_str *d = (struct tunable_str *)data;
|
|
|
|
TUNABLE_STR_FETCH(d->path, d->var, d->size);
|
|
}
|