forked from Mirror/frr
lib: "ferr" error-information system
This provides an API to pass around extra information for errors, more than a simple return value can carry. This is particularly used for the Cap'n Proto interface to be able to report more useful errors. Signed-off-by: David Lamparter <equinox@opensourcerouting.org>
This commit is contained in:
David Lamparter
parent
3df31ebb03
commit
3155489aa2
147
lib/ferr.c
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147
lib/ferr.c
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/*
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* Copyright (c) 2015-16 David Lamparter, for NetDEF, Inc.
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*
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* Permission to use, copy, modify, and distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice appear in all copies.
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*
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* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
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* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
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* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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*/
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#include <stdlib.h>
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#include <stdarg.h>
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#include <string.h>
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#include <pthread.h>
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#include <signal.h>
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#include "ferr.h"
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#include "vty.h"
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#include "jhash.h"
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#include "memory.h"
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DEFINE_MTYPE_STATIC(LIB, ERRINFO, "error information")
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static pthread_key_t errkey;
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static void ferr_free(void *arg)
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{
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XFREE(MTYPE_ERRINFO, arg);
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}
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static void err_key_init(void) __attribute__((_CONSTRUCTOR(500)));
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static void err_key_init(void)
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{
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pthread_key_create(&errkey, ferr_free);
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}
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static void err_key_fini(void) __attribute__((_DESTRUCTOR(500)));
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static void err_key_fini(void)
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{
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pthread_key_delete(errkey);
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}
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const struct ferr *ferr_get_last(ferr_r errval)
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{
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struct ferr *last_error = pthread_getspecific(errkey);
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if (!last_error || last_error->kind == 0)
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return NULL;
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return last_error;
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}
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ferr_r ferr_clear(void)
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{
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struct ferr *last_error = pthread_getspecific(errkey);
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if (last_error)
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last_error->kind = 0;
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return ferr_ok();
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}
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static ferr_r ferr_set_va(const char *file, int line, const char *func,
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enum ferr_kind kind, const char *pathname, int errno_val,
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const char *text, va_list va)
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{
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struct ferr *error = pthread_getspecific(errkey);
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if (!error) {
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error = XCALLOC(MTYPE_ERRINFO, sizeof(*error));
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if (!error) {
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/* we're screwed */
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zlog_err("out of memory while allocating error info");
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raise(SIGSEGV);
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}
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pthread_setspecific(errkey, error);
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}
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error->file = file;
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error->line = line;
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error->func = func;
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error->kind = kind;
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error->unique_id = jhash(text, strlen(text),
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jhash(file, strlen(file), 0xd4ed0298));
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error->errno_val = errno_val;
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if (pathname)
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snprintf(error->pathname, sizeof(error->pathname),
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"%s", pathname);
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else
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error->pathname[0] = '\0';
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vsnprintf(error->message, sizeof(error->message), text, va);
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return -1;
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}
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ferr_r ferr_set_internal(const char *file, int line, const char *func,
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enum ferr_kind kind, const char *text, ...)
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{
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ferr_r rv;
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va_list va;
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va_start(va, text);
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rv = ferr_set_va(file, line, func, kind, NULL, 0, text, va);
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va_end(va);
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return rv;
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}
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ferr_r ferr_set_internal_ext(const char *file, int line, const char *func,
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enum ferr_kind kind, const char *pathname, int errno_val,
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const char *text, ...)
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{
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ferr_r rv;
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va_list va;
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va_start(va, text);
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rv = ferr_set_va(file, line, func, kind, pathname, errno_val, text, va);
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va_end(va);
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return rv;
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}
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#define REPLACE "$ERR"
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void vty_print_error(struct vty *vty, ferr_r err, const char *msg, ...)
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{
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char tmpmsg[512], *replacepos;
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const struct ferr *last_error = ferr_get_last(err);
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va_list va;
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va_start(va, msg);
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vsnprintf(tmpmsg, sizeof(tmpmsg), msg, va);
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va_end(va);
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replacepos = strstr(tmpmsg, REPLACE);
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if (!replacepos)
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vty_out(vty, "%s\n", tmpmsg);
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else {
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replacepos[0] = '\0';
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replacepos += sizeof(REPLACE) - 1;
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vty_out(vty, "%s%s%s\n",
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tmpmsg,
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last_error ? last_error->message : "(no error?)",
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replacepos);
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}
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}
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191
lib/ferr.h
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191
lib/ferr.h
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@ -0,0 +1,191 @@
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/*
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* Copyright (c) 2015-16 David Lamparter, for NetDEF, Inc.
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*
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* Permission to use, copy, modify, and distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice appear in all copies.
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*
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* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
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* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
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* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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*/
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#ifndef _FRR_FERR_H
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#define _FRR_FERR_H
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/***********************************************************
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* scroll down to the end of this file for a full example! *
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***********************************************************/
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#include <stdint.h>
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#include <limits.h>
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#include <errno.h>
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/* return type when this error indication stuff is used.
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*
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* guaranteed to have boolean evaluation to "false" when OK, "true" when error
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* (i.e. can be changed to pointer in the future if neccessary)
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*
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* For checking, always use "if (value)", nothing else.
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* Do _NOT_ use any integer constant (!= 0), or sign check (< 0).
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*/
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typedef int ferr_r;
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/* rough category of error indication */
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enum ferr_kind {
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/* no error */
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FERR_OK = 0,
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/* something isn't the way it's supposed to be.
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* (things that might otherwise be asserts, really)
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*/
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FERR_CODE_BUG,
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/* user-supplied parameters don't make sense or is inconsistent
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* if you can express a rule for it (e.g. "holdtime > 2 * keepalive"),
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* it's this category.
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*/
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FERR_CONFIG_INVALID,
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/* user-supplied parameters don't line up with reality
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* (IP address or interface not available, etc.)
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* NB: these are really TODOs where the code needs to be fixed to
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* respond to future changes!
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*/
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FERR_CONFIG_REALITY,
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/* out of some system resource (probably memory)
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* aka "you didn't spend enough money error" */
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FERR_RESOURCE,
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/* system error (permission denied, etc.) */
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FERR_SYSTEM,
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/* error return from some external library
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* (FERR_SYSTEM and FERR_LIBRARY are not strongly distinct) */
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FERR_LIBRARY,
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};
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struct ferr {
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/* code location */
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const char *file;
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const char *func;
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int line;
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enum ferr_kind kind;
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/* unique_id is calculated as a checksum of source filename and error
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* message format (*before* calling vsnprintf). Line number and
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* function name are not used; this keeps the number reasonably static
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* across changes.
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*/
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uint32_t unique_id;
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char message[384];
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/* valid if != 0. note "errno" might be preprocessor foobar. */
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int errno_val;
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/* valid if pathname[0] != '\0' */
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char pathname[PATH_MAX];
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};
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/* get error details.
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*
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* NB: errval/ferr_r does NOT carry the full error information. It's only
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* passed around for future API flexibility. ferr_get_last always returns
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* the last error set in the current thread.
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*/
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const struct ferr *ferr_get_last(ferr_r errval);
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/* can optionally be called at strategic locations.
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* always returns 0. */
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ferr_r ferr_clear(void);
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/* do NOT call these functions directly. only for macro use! */
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ferr_r ferr_set_internal(const char *file, int line, const char *func,
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enum ferr_kind kind, const char *text, ...);
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ferr_r ferr_set_internal_ext(const char *file, int line, const char *func,
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enum ferr_kind kind, const char *pathname, int errno_val,
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const char *text, ...);
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#define ferr_ok() \
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0
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/* Report an error.
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*
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* If you need to do cleanup (free memory, etc.), save the return value in a
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* variable of type ferr_r.
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*
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* Don't put a \n at the end of the error message.
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*/
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#define ferr_code_bug(...) \
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ferr_set_internal(__FILE__, __LINE__, __func__, FERR_CODE_BUG, \
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__VA_ARGS__)
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#define ferr_cfg_invalid(...) \
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ferr_set_internal(__FILE__, __LINE__, __func__, FERR_CONFIG_INVALID, \
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__VA_ARGS__)
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#define ferr_cfg_reality(...) \
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ferr_set_internal(__FILE__, __LINE__, __func__, FERR_CONFIG_REALITY, \
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__VA_ARGS__)
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#define ferr_cfg_resource(...) \
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ferr_set_internal(__FILE__, __LINE__, __func__, FERR_RESOURCE, \
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__VA_ARGS__)
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#define ferr_system(...) \
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ferr_set_internal(__FILE__, __LINE__, __func__, FERR_SYSTEM, \
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__VA_ARGS__)
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#define ferr_library(...) \
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ferr_set_internal(__FILE__, __LINE__, __func__, FERR_LIBRARY, \
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__VA_ARGS__)
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/* extended information variants */
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#define ferr_system_errno(...) \
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ferr_set_internal_ext(__FILE__, __LINE__, __func__, FERR_SYSTEM, \
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NULL, errno, __VA_ARGS__)
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#define ferr_system_path_errno(path, ...) \
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ferr_set_internal_ext(__FILE__, __LINE__, __func__, FERR_SYSTEM, \
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path, errno, __VA_ARGS__)
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#include "vty.h"
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/* print error message to vty; $ERR is replaced by the error's message */
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void vty_print_error(struct vty *vty, ferr_r err, const char *msg, ...);
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#define CMD_FERR_DO(func, action, ...) \
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do { ferr_r cmd_retval = func; \
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if (cmd_retval) { \
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vty_print_error(vty, cmd_retval, __VA_ARGS__); \
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action; \
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} \
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} while (0)
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#define CMD_FERR_RETURN(func, ...) \
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CMD_FERR_DO(func, return CMD_WARNING, __VA_ARGS__)
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#define CMD_FERR_GOTO(func, label, ...) \
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CMD_FERR_DO(func, goto label, __VA_ARGS__)
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/* example:
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ferr_r foo_bar_set(struct object *obj, int bar)
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{
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if (bar < 1 || bar >= 100)
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return ferr_config_invalid("bar setting (%d) must be 0<x<100", bar);
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obj->bar = bar;
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if (ioctl (obj->fd, bar))
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return ferr_system_errno("couldn't set bar to %d", bar);
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return ferr_ok();
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}
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DEFUN("bla")
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{
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CMD_FERR_RETURN(foo_bar_set(obj, atoi(argv[1])),
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"command failed: $ERR\n");
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return CMD_SUCCESS;
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}
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*/
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#endif /* _FERR_H */
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@ -17,6 +17,7 @@ lib_libfrr_la_SOURCES = \
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lib/csv.c \
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lib/distribute.c \
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lib/event_counter.c \
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lib/ferr.c \
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lib/filter.c \
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lib/frr_pthread.c \
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lib/getopt.c \
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@ -89,6 +90,7 @@ pkginclude_HEADERS += \
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lib/csv.h \
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lib/distribute.h \
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lib/event_counter.h \
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lib/ferr.h \
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lib/fifo.h \
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lib/filter.h \
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lib/freebsd-queue.h \
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