/*- * SPDX-License-Identifier: BSD-2-Clause-FreeBSD * * Copyright (c) 1998 Michael Smith * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. */ /* * The unified bootloader passes us a pointer to a preserved copy of * bootstrap/kernel environment variables. We convert them to a * dynamic array of strings later when the VM subsystem is up. * * We make these available through the kenv(2) syscall for userland * and through kern_getenv()/freeenv() kern_setenv() kern_unsetenv() testenv() for * the kernel. */ #include __FBSDID("$FreeBSD$"); #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include static char *_getenv_dynamic_locked(const char *name, int *idx); static char *_getenv_dynamic(const char *name, int *idx); static char *kenv_acquire(const char *name); static void kenv_release(const char *buf); static MALLOC_DEFINE(M_KENV, "kenv", "kernel environment"); #define KENV_SIZE 512 /* Maximum number of environment strings */ static uma_zone_t kenv_zone; static int kenv_mvallen = KENV_MVALLEN; /* pointer to the config-generated static environment */ char *kern_envp; /* pointer to the md-static environment */ char *md_envp; static int md_env_len; static int md_env_pos; static char *kernenv_next(char *); /* dynamic environment variables */ char **kenvp; struct mtx kenv_lock; /* * No need to protect this with a mutex since SYSINITS are single threaded. */ bool dynamic_kenv; #define KENV_CHECK if (!dynamic_kenv) \ panic("%s: called before SI_SUB_KMEM", __func__) int sys_kenv(td, uap) struct thread *td; struct kenv_args /* { int what; const char *name; char *value; int len; } */ *uap; { char *name, *value, *buffer = NULL; size_t len, done, needed, buflen; int error, i; KASSERT(dynamic_kenv, ("kenv: dynamic_kenv = false")); error = 0; if (uap->what == KENV_DUMP) { #ifdef MAC error = mac_kenv_check_dump(td->td_ucred); if (error) return (error); #endif done = needed = 0; buflen = uap->len; if (buflen > KENV_SIZE * (KENV_MNAMELEN + kenv_mvallen + 2)) buflen = KENV_SIZE * (KENV_MNAMELEN + kenv_mvallen + 2); if (uap->len > 0 && uap->value != NULL) buffer = malloc(buflen, M_TEMP, M_WAITOK|M_ZERO); mtx_lock(&kenv_lock); for (i = 0; kenvp[i] != NULL; i++) { len = strlen(kenvp[i]) + 1; needed += len; len = min(len, buflen - done); /* * If called with a NULL or insufficiently large * buffer, just keep computing the required size. */ if (uap->value != NULL && buffer != NULL && len > 0) { bcopy(kenvp[i], buffer + done, len); done += len; } } mtx_unlock(&kenv_lock); if (buffer != NULL) { error = copyout(buffer, uap->value, done); free(buffer, M_TEMP); } td->td_retval[0] = ((done == needed) ? 0 : needed); return (error); } switch (uap->what) { case KENV_SET: error = priv_check(td, PRIV_KENV_SET); if (error) return (error); break; case KENV_UNSET: error = priv_check(td, PRIV_KENV_UNSET); if (error) return (error); break; } name = malloc(KENV_MNAMELEN + 1, M_TEMP, M_WAITOK); error = copyinstr(uap->name, name, KENV_MNAMELEN + 1, NULL); if (error) goto done; switch (uap->what) { case KENV_GET: #ifdef MAC error = mac_kenv_check_get(td->td_ucred, name); if (error) goto done; #endif value = kern_getenv(name); if (value == NULL) { error = ENOENT; goto done; } len = strlen(value) + 1; if (len > uap->len) len = uap->len; error = copyout(value, uap->value, len); freeenv(value); if (error) goto done; td->td_retval[0] = len; break; case KENV_SET: len = uap->len; if (len < 1) { error = EINVAL; goto done; } if (len > kenv_mvallen + 1) len = kenv_mvallen + 1; value = malloc(len, M_TEMP, M_WAITOK); error = copyinstr(uap->value, value, len, NULL); if (error) { free(value, M_TEMP); goto done; } #ifdef MAC error = mac_kenv_check_set(td->td_ucred, name, value); if (error == 0) #endif kern_setenv(name, value); free(value, M_TEMP); break; case KENV_UNSET: #ifdef MAC error = mac_kenv_check_unset(td->td_ucred, name); if (error) goto done; #endif error = kern_unsetenv(name); if (error) error = ENOENT; break; default: error = EINVAL; break; } done: free(name, M_TEMP); return (error); } /* * Populate the initial kernel environment. * * This is called very early in MD startup, either to provide a copy of the * environment obtained from a boot loader, or to provide an empty buffer into * which MD code can store an initial environment using kern_setenv() calls. * * kern_envp is set to the static_env generated by config(8). This implements * the env keyword described in config(5). * * If len is non-zero, the caller is providing an empty buffer. The caller will * subsequently use kern_setenv() to add up to len bytes of initial environment * before the dynamic environment is available. * * If len is zero, the caller is providing a pre-loaded buffer containing * environment strings. Additional strings cannot be added until the dynamic * environment is available. The memory pointed to must remain stable at least * until sysinit runs init_dynamic_kenv() and preferably until after SI_SUB_KMEM * is finished so that subr_hints routines may continue to use it until the * environments have been fully merged at the end of the pass. If no initial * environment is available from the boot loader, passing a NULL pointer allows * the static_env to be installed if it is configured. In this case, any call * to kern_setenv() prior to the setup of the dynamic environment will result in * a panic. */ void init_static_kenv(char *buf, size_t len) { KASSERT(!dynamic_kenv, ("kenv: dynamic_kenv already initialized")); /* * Suitably sized means it must be able to hold at least one empty * variable, otherwise things go belly up if a kern_getenv call is * made without a prior call to kern_setenv as we have a malformed * environment. */ KASSERT(len == 0 || len >= 2, ("kenv: static env must be initialized or suitably sized")); KASSERT(len == 0 || (*buf == '\0' && *(buf + 1) == '\0'), ("kenv: sized buffer must be initially empty")); /* * We may be called twice, with the second call needed to relocate * md_envp after enabling paging. md_envp is then garbage if it is * not null and the relocation will move it. Discard it so as to * not crash using its old value in our first call to kern_getenv(). * * The second call gives the same environment as the first except * in silly configurations where the static env disables itself. * * Other env calls don't handle possibly-garbage pointers, so must * not be made between enabling paging and calling here. */ md_envp = NULL; md_env_len = 0; md_env_pos = 0; /* * Give the static environment a chance to disable the loader(8) * environment first. This is done with loader_env.disabled=1. * * static_env and static_hints may both be disabled, but in slightly * different ways. For static_env, we just don't setup kern_envp and * it's as if a static env wasn't even provided. For static_hints, * we effectively zero out the buffer to stop the rest of the kernel * from being able to use it. * * We're intentionally setting this up so that static_hints.disabled may * be specified in either the MD env or the static env. This keeps us * consistent in our new world view. * * As a warning, the static environment may not be disabled in any way * if the static environment has disabled the loader environment. */ kern_envp = static_env; if (!getenv_is_true("loader_env.disabled")) { md_envp = buf; md_env_len = len; md_env_pos = 0; if (getenv_is_true("static_env.disabled")) { kern_envp[0] = '\0'; kern_envp[1] = '\0'; } } if (getenv_is_true("static_hints.disabled")) { static_hints[0] = '\0'; static_hints[1] = '\0'; } } static void init_dynamic_kenv_from(char *init_env, int *curpos) { char *cp, *cpnext, *eqpos, *found; size_t len; int i; if (init_env && *init_env != '\0') { found = NULL; i = *curpos; for (cp = init_env; cp != NULL; cp = cpnext) { cpnext = kernenv_next(cp); len = strlen(cp) + 1; if (len > KENV_MNAMELEN + 1 + kenv_mvallen + 1) { printf( "WARNING: too long kenv string, ignoring %s\n", cp); goto sanitize; } eqpos = strchr(cp, '='); if (eqpos == NULL) { printf( "WARNING: malformed static env value, ignoring %s\n", cp); goto sanitize; } *eqpos = 0; /* * De-dupe the environment as we go. We don't add the * duplicated assignments because config(8) will flip * the order of the static environment around to make * kernel processing match the order of specification * in the kernel config. */ found = _getenv_dynamic_locked(cp, NULL); *eqpos = '='; if (found != NULL) goto sanitize; if (i > KENV_SIZE) { printf( "WARNING: too many kenv strings, ignoring %s\n", cp); goto sanitize; } kenvp[i] = malloc(len, M_KENV, M_WAITOK); strcpy(kenvp[i++], cp); sanitize: explicit_bzero(cp, len - 1); } *curpos = i; } } /* * Setup the dynamic kernel environment. */ static void init_dynamic_kenv(void *data __unused) { int dynamic_envpos; int size; TUNABLE_INT_FETCH("kenv_mvallen", &kenv_mvallen); size = KENV_MNAMELEN + 1 + kenv_mvallen + 1; kenv_zone = uma_zcreate("kenv", size, NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, 0); kenvp = malloc((KENV_SIZE + 1) * sizeof(char *), M_KENV, M_WAITOK | M_ZERO); dynamic_envpos = 0; init_dynamic_kenv_from(md_envp, &dynamic_envpos); init_dynamic_kenv_from(kern_envp, &dynamic_envpos); kenvp[dynamic_envpos] = NULL; mtx_init(&kenv_lock, "kernel environment", NULL, MTX_DEF); dynamic_kenv = true; } SYSINIT(kenv, SI_SUB_KMEM + 1, SI_ORDER_FIRST, init_dynamic_kenv, NULL); void freeenv(char *env) { if (dynamic_kenv && env != NULL) { explicit_bzero(env, strlen(env)); uma_zfree(kenv_zone, env); } } /* * Internal functions for string lookup. */ static char * _getenv_dynamic_locked(const char *name, int *idx) { char *cp; int len, i; len = strlen(name); for (cp = kenvp[0], i = 0; cp != NULL; cp = kenvp[++i]) { if ((strncmp(cp, name, len) == 0) && (cp[len] == '=')) { if (idx != NULL) *idx = i; return (cp + len + 1); } } return (NULL); } static char * _getenv_dynamic(const char *name, int *idx) { mtx_assert(&kenv_lock, MA_OWNED); return (_getenv_dynamic_locked(name, idx)); } static char * _getenv_static_from(char *chkenv, const char *name) { char *cp, *ep; int len; for (cp = chkenv; cp != NULL; cp = kernenv_next(cp)) { for (ep = cp; (*ep != '=') && (*ep != 0); ep++) ; if (*ep != '=') continue; len = ep - cp; ep++; if (!strncmp(name, cp, len) && name[len] == 0) return (ep); } return (NULL); } static char * _getenv_static(const char *name) { char *val; val = _getenv_static_from(md_envp, name); if (val != NULL) return (val); val = _getenv_static_from(kern_envp, name); if (val != NULL) return (val); return (NULL); } /* * Look up an environment variable by name. * Return a pointer to the string if found. * The pointer has to be freed with freeenv() * after use. */ char * kern_getenv(const char *name) { char *cp, *ret; int len; if (dynamic_kenv) { len = KENV_MNAMELEN + 1 + kenv_mvallen + 1; ret = uma_zalloc(kenv_zone, M_WAITOK | M_ZERO); mtx_lock(&kenv_lock); cp = _getenv_dynamic(name, NULL); if (cp != NULL) strlcpy(ret, cp, len); mtx_unlock(&kenv_lock); if (cp == NULL) { uma_zfree(kenv_zone, ret); ret = NULL; } } else ret = _getenv_static(name); return (ret); } /* * Test if an environment variable is defined. */ int testenv(const char *name) { char *cp; cp = kenv_acquire(name); kenv_release(cp); if (cp != NULL) return (1); return (0); } /* * Set an environment variable in the MD-static environment. This cannot * feasibly be done on config(8)-generated static environments as they don't * generally include space for extra variables. */ static int setenv_static(const char *name, const char *value) { int len; if (md_env_pos >= md_env_len) return (-1); /* Check space for x=y and two nuls */ len = strlen(name) + strlen(value); if (len + 3 < md_env_len - md_env_pos) { len = sprintf(&md_envp[md_env_pos], "%s=%s", name, value); md_env_pos += len+1; md_envp[md_env_pos] = '\0'; return (0); } else return (-1); } /* * Set an environment variable by name. */ int kern_setenv(const char *name, const char *value) { char *buf, *cp, *oldenv; int namelen, vallen, i; if (!dynamic_kenv && md_env_len > 0) return (setenv_static(name, value)); KENV_CHECK; namelen = strlen(name) + 1; if (namelen > KENV_MNAMELEN + 1) return (-1); vallen = strlen(value) + 1; if (vallen > kenv_mvallen + 1) return (-1); buf = malloc(namelen + vallen, M_KENV, M_WAITOK); sprintf(buf, "%s=%s", name, value); mtx_lock(&kenv_lock); cp = _getenv_dynamic(name, &i); if (cp != NULL) { oldenv = kenvp[i]; kenvp[i] = buf; mtx_unlock(&kenv_lock); free(oldenv, M_KENV); } else { /* We add the option if it wasn't found */ for (i = 0; (cp = kenvp[i]) != NULL; i++) ; /* Bounds checking */ if (i < 0 || i >= KENV_SIZE) { free(buf, M_KENV); mtx_unlock(&kenv_lock); return (-1); } kenvp[i] = buf; kenvp[i + 1] = NULL; mtx_unlock(&kenv_lock); } return (0); } /* * Unset an environment variable string. */ int kern_unsetenv(const char *name) { char *cp, *oldenv; int i, j; KENV_CHECK; mtx_lock(&kenv_lock); cp = _getenv_dynamic(name, &i); if (cp != NULL) { oldenv = kenvp[i]; for (j = i + 1; kenvp[j] != NULL; j++) kenvp[i++] = kenvp[j]; kenvp[i] = NULL; mtx_unlock(&kenv_lock); zfree(oldenv, M_KENV); return (0); } mtx_unlock(&kenv_lock); return (-1); } /* * Return the internal kenv buffer for the variable name, if it exists. * If the dynamic kenv is initialized and the name is present, return * with kenv_lock held. */ static char * kenv_acquire(const char *name) { char *value; if (dynamic_kenv) { mtx_lock(&kenv_lock); value = _getenv_dynamic(name, NULL); if (value == NULL) mtx_unlock(&kenv_lock); return (value); } else return (_getenv_static(name)); } /* * Undo a previous kenv_acquire() operation */ static void kenv_release(const char *buf) { if ((buf != NULL) && dynamic_kenv) mtx_unlock(&kenv_lock); } /* * Return a string value from an environment variable. */ int getenv_string(const char *name, char *data, int size) { char *cp; cp = kenv_acquire(name); if (cp != NULL) strlcpy(data, cp, size); kenv_release(cp); return (cp != NULL); } /* * Return an array of integers at the given type size and signedness. */ int getenv_array(const char *name, void *pdata, int size, int *psize, int type_size, bool allow_signed) { uint8_t shift; int64_t value; int64_t old; const char *buf; char *end; const char *ptr; int n; int rc; rc = 0; /* assume failure */ buf = kenv_acquire(name); if (buf == NULL) goto error; /* get maximum number of elements */ size /= type_size; n = 0; for (ptr = buf; *ptr != 0; ) { value = strtoq(ptr, &end, 0); /* check if signed numbers are allowed */ if (value < 0 && !allow_signed) goto error; /* check for invalid value */ if (ptr == end) goto error; /* check for valid suffix */ switch (*end) { case 't': case 'T': shift = 40; end++; break; case 'g': case 'G': shift = 30; end++; break; case 'm': case 'M': shift = 20; end++; break; case 'k': case 'K': shift = 10; end++; break; case ' ': case '\t': case ',': case 0: shift = 0; break; default: /* garbage after numeric value */ goto error; } /* skip till next value, if any */ while (*end == '\t' || *end == ',' || *end == ' ') end++; /* update pointer */ ptr = end; /* apply shift */ old = value; value <<= shift; /* overflow check */ if ((value >> shift) != old) goto error; /* check for buffer overflow */ if (n >= size) goto error; /* store value according to type size */ switch (type_size) { case 1: if (allow_signed) { if (value < SCHAR_MIN || value > SCHAR_MAX) goto error; } else { if (value < 0 || value > UCHAR_MAX) goto error; } ((uint8_t *)pdata)[n] = (uint8_t)value; break; case 2: if (allow_signed) { if (value < SHRT_MIN || value > SHRT_MAX) goto error; } else { if (value < 0 || value > USHRT_MAX) goto error; } ((uint16_t *)pdata)[n] = (uint16_t)value; break; case 4: if (allow_signed) { if (value < INT_MIN || value > INT_MAX) goto error; } else { if (value > UINT_MAX) goto error; } ((uint32_t *)pdata)[n] = (uint32_t)value; break; case 8: ((uint64_t *)pdata)[n] = (uint64_t)value; break; default: goto error; } n++; } *psize = n * type_size; if (n != 0) rc = 1; /* success */ error: kenv_release(buf); return (rc); } /* * Return an integer value from an environment variable. */ int getenv_int(const char *name, int *data) { quad_t tmp; int rval; rval = getenv_quad(name, &tmp); if (rval) *data = (int) tmp; return (rval); } /* * 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 an int64_t value from an environment variable. */ int getenv_int64(const char *name, int64_t *data) { quad_t tmp; int64_t rval; rval = getenv_quad(name, &tmp); if (rval) *data = (int64_t) tmp; return (rval); } /* * Return an uint64_t value from an environment variable. */ int getenv_uint64(const char *name, uint64_t *data) { quad_t tmp; uint64_t rval; rval = getenv_quad(name, &tmp); if (rval) *data = (uint64_t) 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) { const char *value; char suffix, *vtp; quad_t iv; value = kenv_acquire(name); if (value == NULL) { goto error; } iv = strtoq(value, &vtp, 0); if (vtp == value || (vtp[0] != '\0' && vtp[1] != '\0')) { goto error; } suffix = vtp[0]; kenv_release(value); switch (suffix) { case 't': case 'T': iv *= 1024; /* FALLTHROUGH */ case 'g': case 'G': iv *= 1024; /* FALLTHROUGH */ case 'm': case 'M': iv *= 1024; /* FALLTHROUGH */ case 'k': case 'K': iv *= 1024; case '\0': break; default: return (0); } *data = iv; return (1); error: kenv_release(value); return (0); } /* * Return a boolean value from an environment variable. This can be in * numerical or string form, i.e. "1" or "true". */ int getenv_bool(const char *name, bool *data) { char *val; int ret = 0; if (name == NULL) return (0); val = kern_getenv(name); if (val == NULL) return (0); if ((strcmp(val, "1") == 0) || (strcasecmp(val, "true") == 0)) { *data = true; ret = 1; } else if ((strcmp(val, "0") == 0) || (strcasecmp(val, "false") == 0)) { *data = false; ret = 1; } else { /* Spit out a warning for malformed boolean variables. */ printf("Environment variable %s has non-boolean value \"%s\"\n", name, val); } freeenv(val); return (ret); } /* * Wrapper around getenv_bool to easily check for true. */ bool getenv_is_true(const char *name) { bool val; if (getenv_bool(name, &val) != 0) return (val); return (false); } /* * Wrapper around getenv_bool to easily check for false. */ bool getenv_is_false(const char *name) { bool val; if (getenv_bool(name, &val) != 0) return (!val); return (false); } /* * 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_int64_init(void *data) { struct tunable_int64 *d = (struct tunable_int64 *)data; TUNABLE_INT64_FETCH(d->path, d->var); } void tunable_uint64_init(void *data) { struct tunable_uint64 *d = (struct tunable_uint64 *)data; TUNABLE_UINT64_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_bool_init(void *data) { struct tunable_bool *d = (struct tunable_bool *)data; TUNABLE_BOOL_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); }