/*- * 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 <sys/cdefs.h> __FBSDID("$FreeBSD$"); #include <sys/types.h> #include <sys/param.h> #include <sys/proc.h> #include <sys/queue.h> #include <sys/lock.h> #include <sys/malloc.h> #include <sys/mutex.h> #include <sys/priv.h> #include <sys/kernel.h> #include <sys/systm.h> #include <sys/sysent.h> #include <sys/sysproto.h> #include <sys/libkern.h> #include <sys/kenv.h> #include <security/mac/mac_framework.h> static MALLOC_DEFINE(M_KENV, "kenv", "kernel environment"); #define KENV_SIZE 512 /* Maximum number of environment strings */ /* pointer to the static environment */ char *kern_envp; static int env_len; static int 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. */ int dynamic_kenv = 0; #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 = 0")); 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); } void init_static_kenv(char *buf, size_t len) { kern_envp = buf; env_len = len; env_pos = 0; } /* * Setup the dynamic kernel environment. */ static void init_dynamic_kenv(void *data __unused) { char *cp, *cpnext; size_t len; int i; kenvp = malloc((KENV_SIZE + 1) * sizeof(char *), M_KENV, M_WAITOK | M_ZERO); i = 0; if (kern_envp && *kern_envp != '\0') { for (cp = kern_envp; 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); continue; } if (i < KENV_SIZE) { kenvp[i] = malloc(len, M_KENV, M_WAITOK); strcpy(kenvp[i++], cp); memset(cp, 0, strlen(cp)); } else printf( "WARNING: too many kenv strings, ignoring %s\n", cp); } } kenvp[i] = NULL; mtx_init(&kenv_lock, "kernel environment", NULL, MTX_DEF); dynamic_kenv = 1; } SYSINIT(kenv, SI_SUB_KMEM, SI_ORDER_ANY, init_dynamic_kenv, NULL); void freeenv(char *env) { if (dynamic_kenv && env != NULL) { memset(env, 0, strlen(env)); free(env, M_KENV); } } /* * Internal functions for string lookup. */ static char * _getenv_dynamic(const char *name, int *idx) { char *cp; int len, i; mtx_assert(&kenv_lock, MA_OWNED); 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_static(const char *name) { char *cp, *ep; int len; for (cp = kern_envp; 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); } /* * 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 buf[KENV_MNAMELEN + 1 + KENV_MVALLEN + 1]; char *ret; if (dynamic_kenv) { if (getenv_string(name, buf, sizeof(buf))) { ret = strdup(buf, M_KENV); } else { ret = NULL; WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL, "getenv"); } } else ret = _getenv_static(name); return (ret); } /* * Test if an environment variable is defined. */ int testenv(const char *name) { char *cp; if (dynamic_kenv) { mtx_lock(&kenv_lock); cp = _getenv_dynamic(name, NULL); mtx_unlock(&kenv_lock); } else cp = _getenv_static(name); if (cp != NULL) return (1); return (0); } static int setenv_static(const char *name, const char *value) { int len; if (env_pos >= env_len) return (-1); /* Check space for x=y and two nuls */ len = strlen(name) + strlen(value); if (len + 3 < env_len - env_pos) { len = sprintf(&kern_envp[env_pos], "%s=%s", name, value); env_pos += len+1; kern_envp[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 == 0 && 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); memset(oldenv, 0, strlen(oldenv)); free(oldenv, M_KENV); return (0); } mtx_unlock(&kenv_lock); return (-1); } /* * Return a string value from an environment variable. */ int getenv_string(const char *name, char *data, int size) { char *cp; if (dynamic_kenv) { mtx_lock(&kenv_lock); cp = _getenv_dynamic(name, NULL); if (cp != NULL) strlcpy(data, cp, size); mtx_unlock(&kenv_lock); } else { cp = _getenv_static(name); if (cp != NULL) strlcpy(data, cp, size); } return (cp != NULL); } /* * 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 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); }