1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/security/nss/lib/base/error.c Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,269 @@
1.4 +/* This Source Code Form is subject to the terms of the Mozilla Public
1.5 + * License, v. 2.0. If a copy of the MPL was not distributed with this
1.6 + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
1.7 +
1.8 +/*
1.9 + * error.c
1.10 + *
1.11 + * This file contains the code implementing the per-thread error
1.12 + * stacks upon which most NSS routines report their errors.
1.13 + */
1.14 +
1.15 +#ifndef BASE_H
1.16 +#include "base.h"
1.17 +#endif /* BASE_H */
1.18 +#include <limits.h> /* for UINT_MAX */
1.19 +#include <string.h> /* for memmove */
1.20 +
1.21 +#define NSS_MAX_ERROR_STACK_COUNT 16 /* error codes */
1.22 +
1.23 +/*
1.24 + * The stack itself has a header, and a sequence of integers.
1.25 + * The header records the amount of space (as measured in stack
1.26 + * slots) already allocated for the stack, and the count of the
1.27 + * number of records currently being used.
1.28 + */
1.29 +
1.30 +struct stack_header_str {
1.31 + PRUint16 space;
1.32 + PRUint16 count;
1.33 +};
1.34 +
1.35 +struct error_stack_str {
1.36 + struct stack_header_str header;
1.37 + PRInt32 stack[1];
1.38 +};
1.39 +typedef struct error_stack_str error_stack;
1.40 +
1.41 +/*
1.42 + * error_stack_index
1.43 + *
1.44 + * Thread-private data must be indexed. This is that index.
1.45 + * See PR_NewThreadPrivateIndex for more information.
1.46 + *
1.47 + * Thread-private data indexes are in the range [0, 127].
1.48 + */
1.49 +
1.50 +#define INVALID_TPD_INDEX UINT_MAX
1.51 +static PRUintn error_stack_index = INVALID_TPD_INDEX;
1.52 +
1.53 +/*
1.54 + * call_once
1.55 + *
1.56 + * The thread-private index must be obtained (once!) at runtime.
1.57 + * This block is used for that one-time call.
1.58 + */
1.59 +
1.60 +static PRCallOnceType error_call_once;
1.61 +
1.62 +/*
1.63 + * error_once_function
1.64 + *
1.65 + * This is the once-called callback.
1.66 + */
1.67 +static PRStatus
1.68 +error_once_function ( void)
1.69 +{
1.70 + return PR_NewThreadPrivateIndex(&error_stack_index, PR_Free);
1.71 +}
1.72 +
1.73 +/*
1.74 + * error_get_my_stack
1.75 + *
1.76 + * This routine returns the calling thread's error stack, creating
1.77 + * it if necessary. It may return NULL upon error, which implicitly
1.78 + * means that it ran out of memory.
1.79 + */
1.80 +
1.81 +static error_stack *
1.82 +error_get_my_stack ( void)
1.83 +{
1.84 + PRStatus st;
1.85 + error_stack *rv;
1.86 + PRUintn new_size;
1.87 + PRUint32 new_bytes;
1.88 + error_stack *new_stack;
1.89 +
1.90 + if( INVALID_TPD_INDEX == error_stack_index ) {
1.91 + st = PR_CallOnce(&error_call_once, error_once_function);
1.92 + if( PR_SUCCESS != st ) {
1.93 + return (error_stack *)NULL;
1.94 + }
1.95 + }
1.96 +
1.97 + rv = (error_stack *)PR_GetThreadPrivate(error_stack_index);
1.98 + if( (error_stack *)NULL == rv ) {
1.99 + /* Doesn't exist; create one */
1.100 + new_size = 16;
1.101 + } else if( rv->header.count == rv->header.space &&
1.102 + rv->header.count < NSS_MAX_ERROR_STACK_COUNT ) {
1.103 + /* Too small, expand it */
1.104 + new_size = PR_MIN( rv->header.space * 2, NSS_MAX_ERROR_STACK_COUNT);
1.105 + } else {
1.106 + /* Okay, return it */
1.107 + return rv;
1.108 + }
1.109 +
1.110 + new_bytes = (new_size * sizeof(PRInt32)) + sizeof(error_stack);
1.111 + /* Use NSPR's calloc/realloc, not NSS's, to avoid loops! */
1.112 + new_stack = PR_Calloc(1, new_bytes);
1.113 +
1.114 + if( (error_stack *)NULL != new_stack ) {
1.115 + if( (error_stack *)NULL != rv ) {
1.116 + (void)nsslibc_memcpy(new_stack,rv,rv->header.space);
1.117 + }
1.118 + new_stack->header.space = new_size;
1.119 + }
1.120 +
1.121 + /* Set the value, whether or not the allocation worked */
1.122 + PR_SetThreadPrivate(error_stack_index, new_stack);
1.123 + return new_stack;
1.124 +}
1.125 +
1.126 +/*
1.127 + * The error stack
1.128 + *
1.129 + * The public methods relating to the error stack are:
1.130 + *
1.131 + * NSS_GetError
1.132 + * NSS_GetErrorStack
1.133 + *
1.134 + * The nonpublic methods relating to the error stack are:
1.135 + *
1.136 + * nss_SetError
1.137 + * nss_ClearErrorStack
1.138 + *
1.139 + */
1.140 +
1.141 +/*
1.142 + * NSS_GetError
1.143 + *
1.144 + * This routine returns the highest-level (most general) error set
1.145 + * by the most recent NSS library routine called by the same thread
1.146 + * calling this routine.
1.147 + *
1.148 + * This routine cannot fail. However, it may return zero, which
1.149 + * indicates that the previous NSS library call did not set an error.
1.150 + *
1.151 + * Return value:
1.152 + * 0 if no error has been set
1.153 + * A nonzero error number
1.154 + */
1.155 +
1.156 +NSS_IMPLEMENT PRInt32
1.157 +NSS_GetError ( void)
1.158 +{
1.159 + error_stack *es = error_get_my_stack();
1.160 +
1.161 + if( (error_stack *)NULL == es ) {
1.162 + return NSS_ERROR_NO_MEMORY; /* Good guess! */
1.163 + }
1.164 +
1.165 + if( 0 == es->header.count ) {
1.166 + return 0;
1.167 + }
1.168 +
1.169 + return es->stack[ es->header.count-1 ];
1.170 +}
1.171 +
1.172 +/*
1.173 + * NSS_GetErrorStack
1.174 + *
1.175 + * This routine returns a pointer to an array of integers, containing
1.176 + * the entire sequence or "stack" of errors set by the most recent NSS
1.177 + * library routine called by the same thread calling this routine.
1.178 + * NOTE: the caller DOES NOT OWN the memory pointed to by the return
1.179 + * value. The pointer will remain valid until the calling thread
1.180 + * calls another NSS routine. The lowest-level (most specific) error
1.181 + * is first in the array, and the highest-level is last. The array is
1.182 + * zero-terminated. This routine may return NULL upon error; this
1.183 + * indicates a low-memory situation.
1.184 + *
1.185 + * Return value:
1.186 + * NULL upon error, which is an implied NSS_ERROR_NO_MEMORY
1.187 + * A NON-caller-owned pointer to an array of integers
1.188 + */
1.189 +
1.190 +NSS_IMPLEMENT PRInt32 *
1.191 +NSS_GetErrorStack ( void)
1.192 +{
1.193 + error_stack *es = error_get_my_stack();
1.194 +
1.195 + if( (error_stack *)NULL == es ) {
1.196 + return (PRInt32 *)NULL;
1.197 + }
1.198 +
1.199 + /* Make sure it's terminated */
1.200 + es->stack[ es->header.count ] = 0;
1.201 +
1.202 + return es->stack;
1.203 +}
1.204 +
1.205 +/*
1.206 + * nss_SetError
1.207 + *
1.208 + * This routine places a new error code on the top of the calling
1.209 + * thread's error stack. Calling this routine wiht an error code
1.210 + * of zero will clear the error stack.
1.211 + */
1.212 +
1.213 +NSS_IMPLEMENT void
1.214 +nss_SetError ( PRUint32 error)
1.215 +{
1.216 + error_stack *es;
1.217 +
1.218 + if( 0 == error ) {
1.219 + nss_ClearErrorStack();
1.220 + return;
1.221 + }
1.222 +
1.223 + es = error_get_my_stack();
1.224 + if( (error_stack *)NULL == es ) {
1.225 + /* Oh, well. */
1.226 + return;
1.227 + }
1.228 +
1.229 + if (es->header.count < es->header.space) {
1.230 + es->stack[ es->header.count++ ] = error;
1.231 + } else {
1.232 + memmove(es->stack, es->stack + 1,
1.233 + (es->header.space - 1) * (sizeof es->stack[0]));
1.234 + es->stack[ es->header.space - 1 ] = error;
1.235 + }
1.236 + return;
1.237 +}
1.238 +
1.239 +/*
1.240 + * nss_ClearErrorStack
1.241 + *
1.242 + * This routine clears the calling thread's error stack.
1.243 + */
1.244 +
1.245 +NSS_IMPLEMENT void
1.246 +nss_ClearErrorStack ( void)
1.247 +{
1.248 + error_stack *es = error_get_my_stack();
1.249 + if( (error_stack *)NULL == es ) {
1.250 + /* Oh, well. */
1.251 + return;
1.252 + }
1.253 +
1.254 + es->header.count = 0;
1.255 + es->stack[0] = 0;
1.256 + return;
1.257 +}
1.258 +
1.259 +/*
1.260 + * nss_DestroyErrorStack
1.261 + *
1.262 + * This routine frees the calling thread's error stack.
1.263 + */
1.264 +
1.265 +NSS_IMPLEMENT void
1.266 +nss_DestroyErrorStack ( void)
1.267 +{
1.268 + if( INVALID_TPD_INDEX != error_stack_index ) {
1.269 + PR_SetThreadPrivate(error_stack_index, NULL);
1.270 + }
1.271 + return;
1.272 +}
