openssl/crypto/err/err.c
Richard Levitte 165f1c3ef3 In err_cleanup(), cleanup the thread local storage too
Fixes #3033

Reviewed-by: Matt Caswell <matt@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/3035)
2017-03-27 12:54:40 +02:00

771 lines
20 KiB
C

/*
* Copyright 1995-2016 The OpenSSL Project Authors. All Rights Reserved.
*
* Licensed under the OpenSSL license (the "License"). You may not use
* this file except in compliance with the License. You can obtain a copy
* in the file LICENSE in the source distribution or at
* https://www.openssl.org/source/license.html
*/
#include <stdio.h>
#include <stdarg.h>
#include <string.h>
#include <internal/cryptlib_int.h>
#include <internal/err.h>
#include <internal/err_int.h>
#include <openssl/lhash.h>
#include <openssl/crypto.h>
#include <openssl/buffer.h>
#include <openssl/bio.h>
#include <openssl/opensslconf.h>
#include <internal/thread_once.h>
static void err_load_strings(int lib, ERR_STRING_DATA *str);
static void ERR_STATE_free(ERR_STATE *s);
#ifndef OPENSSL_NO_ERR
static ERR_STRING_DATA ERR_str_libraries[] = {
{ERR_PACK(ERR_LIB_NONE, 0, 0), "unknown library"},
{ERR_PACK(ERR_LIB_SYS, 0, 0), "system library"},
{ERR_PACK(ERR_LIB_BN, 0, 0), "bignum routines"},
{ERR_PACK(ERR_LIB_RSA, 0, 0), "rsa routines"},
{ERR_PACK(ERR_LIB_DH, 0, 0), "Diffie-Hellman routines"},
{ERR_PACK(ERR_LIB_EVP, 0, 0), "digital envelope routines"},
{ERR_PACK(ERR_LIB_BUF, 0, 0), "memory buffer routines"},
{ERR_PACK(ERR_LIB_OBJ, 0, 0), "object identifier routines"},
{ERR_PACK(ERR_LIB_PEM, 0, 0), "PEM routines"},
{ERR_PACK(ERR_LIB_DSA, 0, 0), "dsa routines"},
{ERR_PACK(ERR_LIB_X509, 0, 0), "x509 certificate routines"},
{ERR_PACK(ERR_LIB_ASN1, 0, 0), "asn1 encoding routines"},
{ERR_PACK(ERR_LIB_CONF, 0, 0), "configuration file routines"},
{ERR_PACK(ERR_LIB_CRYPTO, 0, 0), "common libcrypto routines"},
{ERR_PACK(ERR_LIB_EC, 0, 0), "elliptic curve routines"},
{ERR_PACK(ERR_LIB_ECDSA, 0, 0), "ECDSA routines"},
{ERR_PACK(ERR_LIB_ECDH, 0, 0), "ECDH routines"},
{ERR_PACK(ERR_LIB_SSL, 0, 0), "SSL routines"},
{ERR_PACK(ERR_LIB_BIO, 0, 0), "BIO routines"},
{ERR_PACK(ERR_LIB_PKCS7, 0, 0), "PKCS7 routines"},
{ERR_PACK(ERR_LIB_X509V3, 0, 0), "X509 V3 routines"},
{ERR_PACK(ERR_LIB_PKCS12, 0, 0), "PKCS12 routines"},
{ERR_PACK(ERR_LIB_RAND, 0, 0), "random number generator"},
{ERR_PACK(ERR_LIB_DSO, 0, 0), "DSO support routines"},
{ERR_PACK(ERR_LIB_TS, 0, 0), "time stamp routines"},
{ERR_PACK(ERR_LIB_ENGINE, 0, 0), "engine routines"},
{ERR_PACK(ERR_LIB_OCSP, 0, 0), "OCSP routines"},
{ERR_PACK(ERR_LIB_UI, 0, 0), "UI routines"},
{ERR_PACK(ERR_LIB_FIPS, 0, 0), "FIPS routines"},
{ERR_PACK(ERR_LIB_CMS, 0, 0), "CMS routines"},
{ERR_PACK(ERR_LIB_HMAC, 0, 0), "HMAC routines"},
{ERR_PACK(ERR_LIB_CT, 0, 0), "CT routines"},
{ERR_PACK(ERR_LIB_ASYNC, 0, 0), "ASYNC routines"},
{ERR_PACK(ERR_LIB_KDF, 0, 0), "KDF routines"},
{0, NULL},
};
static ERR_STRING_DATA ERR_str_functs[] = {
{ERR_PACK(0, SYS_F_FOPEN, 0), "fopen"},
{ERR_PACK(0, SYS_F_CONNECT, 0), "connect"},
{ERR_PACK(0, SYS_F_GETSERVBYNAME, 0), "getservbyname"},
{ERR_PACK(0, SYS_F_SOCKET, 0), "socket"},
{ERR_PACK(0, SYS_F_IOCTLSOCKET, 0), "ioctlsocket"},
{ERR_PACK(0, SYS_F_BIND, 0), "bind"},
{ERR_PACK(0, SYS_F_LISTEN, 0), "listen"},
{ERR_PACK(0, SYS_F_ACCEPT, 0), "accept"},
# ifdef OPENSSL_SYS_WINDOWS
{ERR_PACK(0, SYS_F_WSASTARTUP, 0), "WSAstartup"},
# endif
{ERR_PACK(0, SYS_F_OPENDIR, 0), "opendir"},
{ERR_PACK(0, SYS_F_FREAD, 0), "fread"},
{ERR_PACK(0, SYS_F_GETADDRINFO, 0), "getaddrinfo"},
{ERR_PACK(0, SYS_F_GETNAMEINFO, 0), "getnameinfo"},
{ERR_PACK(0, SYS_F_SETSOCKOPT, 0), "setsockopt"},
{ERR_PACK(0, SYS_F_GETSOCKOPT, 0), "getsockopt"},
{ERR_PACK(0, SYS_F_GETSOCKNAME, 0), "getsockname"},
{ERR_PACK(0, SYS_F_GETHOSTBYNAME, 0), "gethostbyname"},
{0, NULL},
};
static ERR_STRING_DATA ERR_str_reasons[] = {
{ERR_R_SYS_LIB, "system lib"},
{ERR_R_BN_LIB, "BN lib"},
{ERR_R_RSA_LIB, "RSA lib"},
{ERR_R_DH_LIB, "DH lib"},
{ERR_R_EVP_LIB, "EVP lib"},
{ERR_R_BUF_LIB, "BUF lib"},
{ERR_R_OBJ_LIB, "OBJ lib"},
{ERR_R_PEM_LIB, "PEM lib"},
{ERR_R_DSA_LIB, "DSA lib"},
{ERR_R_X509_LIB, "X509 lib"},
{ERR_R_ASN1_LIB, "ASN1 lib"},
{ERR_R_EC_LIB, "EC lib"},
{ERR_R_BIO_LIB, "BIO lib"},
{ERR_R_PKCS7_LIB, "PKCS7 lib"},
{ERR_R_X509V3_LIB, "X509V3 lib"},
{ERR_R_ENGINE_LIB, "ENGINE lib"},
{ERR_R_ECDSA_LIB, "ECDSA lib"},
{ERR_R_NESTED_ASN1_ERROR, "nested asn1 error"},
{ERR_R_MISSING_ASN1_EOS, "missing asn1 eos"},
{ERR_R_FATAL, "fatal"},
{ERR_R_MALLOC_FAILURE, "malloc failure"},
{ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED,
"called a function you should not call"},
{ERR_R_PASSED_NULL_PARAMETER, "passed a null parameter"},
{ERR_R_INTERNAL_ERROR, "internal error"},
{ERR_R_DISABLED, "called a function that was disabled at compile-time"},
{ERR_R_INIT_FAIL, "init fail"},
{0, NULL},
};
#endif
static CRYPTO_ONCE err_init = CRYPTO_ONCE_STATIC_INIT;
static CRYPTO_THREAD_LOCAL err_thread_local;
static CRYPTO_ONCE err_string_init = CRYPTO_ONCE_STATIC_INIT;
static CRYPTO_RWLOCK *err_string_lock;
static ERR_STRING_DATA *int_err_get_item(const ERR_STRING_DATA *);
/*
* The internal state
*/
static LHASH_OF(ERR_STRING_DATA) *int_error_hash = NULL;
static int int_err_library_number = ERR_LIB_USER;
static unsigned long get_error_values(int inc, int top, const char **file,
int *line, const char **data,
int *flags);
static unsigned long err_string_data_hash(const ERR_STRING_DATA *a)
{
unsigned long ret, l;
l = a->error;
ret = l ^ ERR_GET_LIB(l) ^ ERR_GET_FUNC(l);
return (ret ^ ret % 19 * 13);
}
static int err_string_data_cmp(const ERR_STRING_DATA *a,
const ERR_STRING_DATA *b)
{
return (int)(a->error - b->error);
}
static ERR_STRING_DATA *int_err_get_item(const ERR_STRING_DATA *d)
{
ERR_STRING_DATA *p = NULL;
CRYPTO_THREAD_read_lock(err_string_lock);
if (int_error_hash != NULL)
p = lh_ERR_STRING_DATA_retrieve(int_error_hash, d);
CRYPTO_THREAD_unlock(err_string_lock);
return p;
}
#ifndef OPENSSL_NO_ERR
# define NUM_SYS_STR_REASONS 127
# define LEN_SYS_STR_REASON 32
static ERR_STRING_DATA SYS_str_reasons[NUM_SYS_STR_REASONS + 1];
/*
* SYS_str_reasons is filled with copies of strerror() results at
* initialization. 'errno' values up to 127 should cover all usual errors,
* others will be displayed numerically by ERR_error_string. It is crucial
* that we have something for each reason code that occurs in
* ERR_str_reasons, or bogus reason strings will be returned for SYSerr(),
* which always gets an errno value and never one of those 'standard' reason
* codes.
*/
static void build_SYS_str_reasons(void)
{
/* OPENSSL_malloc cannot be used here, use static storage instead */
static char strerror_tab[NUM_SYS_STR_REASONS][LEN_SYS_STR_REASON];
static int init = 1;
int i;
CRYPTO_THREAD_write_lock(err_string_lock);
if (!init) {
CRYPTO_THREAD_unlock(err_string_lock);
return;
}
for (i = 1; i <= NUM_SYS_STR_REASONS; i++) {
ERR_STRING_DATA *str = &SYS_str_reasons[i - 1];
str->error = (unsigned long)i;
if (str->string == NULL) {
char (*dest)[LEN_SYS_STR_REASON] = &(strerror_tab[i - 1]);
if (openssl_strerror_r(i, *dest, sizeof(*dest)))
str->string = *dest;
}
if (str->string == NULL)
str->string = "unknown";
}
/*
* Now we still have SYS_str_reasons[NUM_SYS_STR_REASONS] = {0, NULL}, as
* required by ERR_load_strings.
*/
init = 0;
CRYPTO_THREAD_unlock(err_string_lock);
}
#endif
#define err_clear_data(p,i) \
do { \
if ((p)->err_data_flags[i] & ERR_TXT_MALLOCED) \
{ \
OPENSSL_free((p)->err_data[i]); \
(p)->err_data[i]=NULL; \
} \
(p)->err_data_flags[i]=0; \
} while(0)
#define err_clear(p,i) \
do { \
(p)->err_flags[i]=0; \
(p)->err_buffer[i]=0; \
err_clear_data(p,i); \
(p)->err_file[i]=NULL; \
(p)->err_line[i]= -1; \
} while(0)
static void ERR_STATE_free(ERR_STATE *s)
{
int i;
if (s == NULL)
return;
for (i = 0; i < ERR_NUM_ERRORS; i++) {
err_clear_data(s, i);
}
OPENSSL_free(s);
}
DEFINE_RUN_ONCE_STATIC(do_err_strings_init)
{
OPENSSL_init_crypto(0, NULL);
err_string_lock = CRYPTO_THREAD_lock_new();
return err_string_lock != NULL;
}
void err_cleanup(void)
{
CRYPTO_THREAD_cleanup_local(&err_thread_local);
CRYPTO_THREAD_lock_free(err_string_lock);
err_string_lock = NULL;
}
int ERR_load_ERR_strings(void)
{
#ifndef OPENSSL_NO_ERR
if (!RUN_ONCE(&err_string_init, do_err_strings_init))
return 0;
err_load_strings(0, ERR_str_libraries);
err_load_strings(0, ERR_str_reasons);
err_load_strings(ERR_LIB_SYS, ERR_str_functs);
build_SYS_str_reasons();
err_load_strings(ERR_LIB_SYS, SYS_str_reasons);
#endif
return 1;
}
static void err_load_strings(int lib, ERR_STRING_DATA *str)
{
CRYPTO_THREAD_write_lock(err_string_lock);
if (int_error_hash == NULL)
int_error_hash = lh_ERR_STRING_DATA_new(err_string_data_hash,
err_string_data_cmp);
if (int_error_hash != NULL) {
for (; str->error; str++) {
if (lib)
str->error |= ERR_PACK(lib, 0, 0);
(void)lh_ERR_STRING_DATA_insert(int_error_hash, str);
}
}
CRYPTO_THREAD_unlock(err_string_lock);
}
int ERR_load_strings(int lib, ERR_STRING_DATA *str)
{
if (ERR_load_ERR_strings() == 0)
return 0;
err_load_strings(lib, str);
return 1;
}
int ERR_unload_strings(int lib, ERR_STRING_DATA *str)
{
if (!RUN_ONCE(&err_string_init, do_err_strings_init))
return 0;
CRYPTO_THREAD_write_lock(err_string_lock);
if (int_error_hash != NULL) {
for (; str->error; str++) {
if (lib)
str->error |= ERR_PACK(lib, 0, 0);
(void)lh_ERR_STRING_DATA_delete(int_error_hash, str);
}
}
CRYPTO_THREAD_unlock(err_string_lock);
return 1;
}
void err_free_strings_int(void)
{
if (!RUN_ONCE(&err_string_init, do_err_strings_init))
return;
CRYPTO_THREAD_write_lock(err_string_lock);
lh_ERR_STRING_DATA_free(int_error_hash);
int_error_hash = NULL;
CRYPTO_THREAD_unlock(err_string_lock);
}
/********************************************************/
void ERR_put_error(int lib, int func, int reason, const char *file, int line)
{
ERR_STATE *es;
#ifdef _OSD_POSIX
/*
* In the BS2000-OSD POSIX subsystem, the compiler generates path names
* in the form "*POSIX(/etc/passwd)". This dirty hack strips them to
* something sensible. @@@ We shouldn't modify a const string, though.
*/
if (strncmp(file, "*POSIX(", sizeof("*POSIX(") - 1) == 0) {
char *end;
/* Skip the "*POSIX(" prefix */
file += sizeof("*POSIX(") - 1;
end = &file[strlen(file) - 1];
if (*end == ')')
*end = '\0';
/* Optional: use the basename of the path only. */
if ((end = strrchr(file, '/')) != NULL)
file = &end[1];
}
#endif
es = ERR_get_state();
es->top = (es->top + 1) % ERR_NUM_ERRORS;
if (es->top == es->bottom)
es->bottom = (es->bottom + 1) % ERR_NUM_ERRORS;
es->err_flags[es->top] = 0;
es->err_buffer[es->top] = ERR_PACK(lib, func, reason);
es->err_file[es->top] = file;
es->err_line[es->top] = line;
err_clear_data(es, es->top);
}
void ERR_clear_error(void)
{
int i;
ERR_STATE *es;
es = ERR_get_state();
for (i = 0; i < ERR_NUM_ERRORS; i++) {
err_clear(es, i);
}
es->top = es->bottom = 0;
}
unsigned long ERR_get_error(void)
{
return (get_error_values(1, 0, NULL, NULL, NULL, NULL));
}
unsigned long ERR_get_error_line(const char **file, int *line)
{
return (get_error_values(1, 0, file, line, NULL, NULL));
}
unsigned long ERR_get_error_line_data(const char **file, int *line,
const char **data, int *flags)
{
return (get_error_values(1, 0, file, line, data, flags));
}
unsigned long ERR_peek_error(void)
{
return (get_error_values(0, 0, NULL, NULL, NULL, NULL));
}
unsigned long ERR_peek_error_line(const char **file, int *line)
{
return (get_error_values(0, 0, file, line, NULL, NULL));
}
unsigned long ERR_peek_error_line_data(const char **file, int *line,
const char **data, int *flags)
{
return (get_error_values(0, 0, file, line, data, flags));
}
unsigned long ERR_peek_last_error(void)
{
return (get_error_values(0, 1, NULL, NULL, NULL, NULL));
}
unsigned long ERR_peek_last_error_line(const char **file, int *line)
{
return (get_error_values(0, 1, file, line, NULL, NULL));
}
unsigned long ERR_peek_last_error_line_data(const char **file, int *line,
const char **data, int *flags)
{
return (get_error_values(0, 1, file, line, data, flags));
}
static unsigned long get_error_values(int inc, int top, const char **file,
int *line, const char **data,
int *flags)
{
int i = 0;
ERR_STATE *es;
unsigned long ret;
es = ERR_get_state();
if (inc && top) {
if (file)
*file = "";
if (line)
*line = 0;
if (data)
*data = "";
if (flags)
*flags = 0;
return ERR_R_INTERNAL_ERROR;
}
if (es->bottom == es->top)
return 0;
if (top)
i = es->top; /* last error */
else
i = (es->bottom + 1) % ERR_NUM_ERRORS; /* first error */
ret = es->err_buffer[i];
if (inc) {
es->bottom = i;
es->err_buffer[i] = 0;
}
if ((file != NULL) && (line != NULL)) {
if (es->err_file[i] == NULL) {
*file = "NA";
if (line != NULL)
*line = 0;
} else {
*file = es->err_file[i];
if (line != NULL)
*line = es->err_line[i];
}
}
if (data == NULL) {
if (inc) {
err_clear_data(es, i);
}
} else {
if (es->err_data[i] == NULL) {
*data = "";
if (flags != NULL)
*flags = 0;
} else {
*data = es->err_data[i];
if (flags != NULL)
*flags = es->err_data_flags[i];
}
}
return ret;
}
void ERR_error_string_n(unsigned long e, char *buf, size_t len)
{
char lsbuf[64], fsbuf[64], rsbuf[64];
const char *ls, *fs, *rs;
unsigned long l, f, r;
if (len == 0)
return;
l = ERR_GET_LIB(e);
f = ERR_GET_FUNC(e);
r = ERR_GET_REASON(e);
ls = ERR_lib_error_string(e);
fs = ERR_func_error_string(e);
rs = ERR_reason_error_string(e);
if (ls == NULL)
BIO_snprintf(lsbuf, sizeof(lsbuf), "lib(%lu)", l);
if (fs == NULL)
BIO_snprintf(fsbuf, sizeof(fsbuf), "func(%lu)", f);
if (rs == NULL)
BIO_snprintf(rsbuf, sizeof(rsbuf), "reason(%lu)", r);
BIO_snprintf(buf, len, "error:%08lX:%s:%s:%s", e, ls ? ls : lsbuf,
fs ? fs : fsbuf, rs ? rs : rsbuf);
if (strlen(buf) == len - 1) {
/*
* output may be truncated; make sure we always have 5
* colon-separated fields, i.e. 4 colons ...
*/
#define NUM_COLONS 4
if (len > NUM_COLONS) { /* ... if possible */
int i;
char *s = buf;
for (i = 0; i < NUM_COLONS; i++) {
char *colon = strchr(s, ':');
if (colon == NULL || colon > &buf[len - 1] - NUM_COLONS + i) {
/*
* set colon no. i at last possible position (buf[len-1]
* is the terminating 0)
*/
colon = &buf[len - 1] - NUM_COLONS + i;
*colon = ':';
}
s = colon + 1;
}
}
}
}
/*
* ERR_error_string_n should be used instead for ret != NULL as
* ERR_error_string cannot know how large the buffer is
*/
char *ERR_error_string(unsigned long e, char *ret)
{
static char buf[256];
if (ret == NULL)
ret = buf;
ERR_error_string_n(e, ret, 256);
return ret;
}
const char *ERR_lib_error_string(unsigned long e)
{
ERR_STRING_DATA d, *p;
unsigned long l;
if (!RUN_ONCE(&err_string_init, do_err_strings_init)) {
return NULL;
}
l = ERR_GET_LIB(e);
d.error = ERR_PACK(l, 0, 0);
p = int_err_get_item(&d);
return ((p == NULL) ? NULL : p->string);
}
const char *ERR_func_error_string(unsigned long e)
{
ERR_STRING_DATA d, *p;
unsigned long l, f;
if (!RUN_ONCE(&err_string_init, do_err_strings_init)) {
return NULL;
}
l = ERR_GET_LIB(e);
f = ERR_GET_FUNC(e);
d.error = ERR_PACK(l, f, 0);
p = int_err_get_item(&d);
return ((p == NULL) ? NULL : p->string);
}
const char *ERR_reason_error_string(unsigned long e)
{
ERR_STRING_DATA d, *p = NULL;
unsigned long l, r;
if (!RUN_ONCE(&err_string_init, do_err_strings_init)) {
return NULL;
}
l = ERR_GET_LIB(e);
r = ERR_GET_REASON(e);
d.error = ERR_PACK(l, 0, r);
p = int_err_get_item(&d);
if (!p) {
d.error = ERR_PACK(0, 0, r);
p = int_err_get_item(&d);
}
return ((p == NULL) ? NULL : p->string);
}
void err_delete_thread_state(void)
{
ERR_STATE *state = ERR_get_state();
if (state == NULL)
return;
CRYPTO_THREAD_set_local(&err_thread_local, NULL);
ERR_STATE_free(state);
}
#if OPENSSL_API_COMPAT < 0x10100000L
void ERR_remove_thread_state(void *dummy)
{
}
#endif
#if OPENSSL_API_COMPAT < 0x10000000L
void ERR_remove_state(unsigned long pid)
{
}
#endif
DEFINE_RUN_ONCE_STATIC(err_do_init)
{
return CRYPTO_THREAD_init_local(&err_thread_local, NULL);
}
ERR_STATE *ERR_get_state(void)
{
ERR_STATE *state = NULL;
if (!RUN_ONCE(&err_init, err_do_init))
return NULL;
state = CRYPTO_THREAD_get_local(&err_thread_local);
if (state == NULL) {
state = OPENSSL_zalloc(sizeof(*state));
if (state == NULL)
return NULL;
if (!CRYPTO_THREAD_set_local(&err_thread_local, state)) {
ERR_STATE_free(state);
return NULL;
}
/* Ignore failures from these */
OPENSSL_init_crypto(OPENSSL_INIT_LOAD_CRYPTO_STRINGS, NULL);
ossl_init_thread_start(OPENSSL_INIT_THREAD_ERR_STATE);
}
return state;
}
int ERR_get_next_error_library(void)
{
int ret;
if (!RUN_ONCE(&err_string_init, do_err_strings_init)) {
return 0;
}
CRYPTO_THREAD_write_lock(err_string_lock);
ret = int_err_library_number++;
CRYPTO_THREAD_unlock(err_string_lock);
return ret;
}
void ERR_set_error_data(char *data, int flags)
{
ERR_STATE *es;
int i;
es = ERR_get_state();
i = es->top;
if (i == 0)
i = ERR_NUM_ERRORS - 1;
err_clear_data(es, i);
es->err_data[i] = data;
es->err_data_flags[i] = flags;
}
void ERR_add_error_data(int num, ...)
{
va_list args;
va_start(args, num);
ERR_add_error_vdata(num, args);
va_end(args);
}
void ERR_add_error_vdata(int num, va_list args)
{
int i, n, s;
char *str, *p, *a;
s = 80;
str = OPENSSL_malloc(s + 1);
if (str == NULL)
return;
str[0] = '\0';
n = 0;
for (i = 0; i < num; i++) {
a = va_arg(args, char *);
/* ignore NULLs, thanks to Bob Beck <beck@obtuse.com> */
if (a != NULL) {
n += strlen(a);
if (n > s) {
s = n + 20;
p = OPENSSL_realloc(str, s + 1);
if (p == NULL) {
OPENSSL_free(str);
return;
}
str = p;
}
OPENSSL_strlcat(str, a, (size_t)s + 1);
}
}
ERR_set_error_data(str, ERR_TXT_MALLOCED | ERR_TXT_STRING);
}
int ERR_set_mark(void)
{
ERR_STATE *es;
es = ERR_get_state();
if (es->bottom == es->top)
return 0;
es->err_flags[es->top] |= ERR_FLAG_MARK;
return 1;
}
int ERR_pop_to_mark(void)
{
ERR_STATE *es;
es = ERR_get_state();
while (es->bottom != es->top
&& (es->err_flags[es->top] & ERR_FLAG_MARK) == 0) {
err_clear(es, es->top);
es->top -= 1;
if (es->top == -1)
es->top = ERR_NUM_ERRORS - 1;
}
if (es->bottom == es->top)
return 0;
es->err_flags[es->top] &= ~ERR_FLAG_MARK;
return 1;
}