lib/zlog.h

   1 /*
   2  * Copyright (c) 2015-19  David Lamparter, for NetDEF, Inc.
   3  *
   4  * Permission to use, copy, modify, and distribute this software for any
   5  * purpose with or without fee is hereby granted, provided that the above
   6  * copyright notice and this permission notice appear in all copies.
   7  *
   8  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
   9  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  10  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
  11  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  12  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  13  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
  14  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  15  */
  16
  17 #ifndef _FRR_ZLOG_H
  18 #define _FRR_ZLOG_H
  19
  20 #include <stdarg.h>
  21 #include <stdbool.h>
  22 #include <stdint.h>
  23 #include <string.h>
  24 #include <syslog.h>
  25 #include <unistd.h>
  26 #include <sys/uio.h>
  27
  28 #include <assert.h>
  29
  30 #include "atomlist.h"
  31 #include "frrcu.h"
  32 #include "memory.h"
  33 #include "hook.h"
  34 #include "printfrr.h"
  35
  36 #ifdef __cplusplus
  37 extern "C" {
  38 #endif
  39
  40 DECLARE_MGROUP(LOG);
  41
  42 extern char zlog_prefix[];
  43 extern size_t zlog_prefixsz;
  44 extern int zlog_tmpdirfd;
  45 extern int zlog_instance;
  46 extern const char *zlog_progname;
  47
  48 struct xref_logmsg {
  49         struct xref xref;
  50
  51         const char *fmtstring;
  52         uint32_t priority;
  53         uint32_t ec;
  54         const char *args;
  55 };
  56
  57 struct xrefdata_logmsg {
  58         struct xrefdata xrefdata;
  59
  60         /* nothing more here right now */
  61 };
  62
  63 /* These functions are set up to write to stdout/stderr without explicit
  64  * initialization and/or before config load.  There is no need to call e.g.
  65  * fprintf(stderr, ...) just because it's "too early" at startup.  Depending
  66  * on context, it may still be the right thing to use fprintf though -- try to
  67  * determine wether something is a log message or something else.
  68  */
  69
  70 extern void vzlogx(const struct xref_logmsg *xref, int prio,
  71                    const char *fmt, va_list ap);
  72 #define vzlog(prio, ...) vzlogx(NULL, prio, __VA_ARGS__)
  73
  74 PRINTFRR(2, 3)
  75 static inline void zlog(int prio, const char *fmt, ...)
  76 {
  77         va_list ap;
  78
  79         va_start(ap, fmt);
  80         vzlog(prio, fmt, ap);
  81         va_end(ap);
  82 }
  83
  84 PRINTFRR(2, 3)
  85 static inline void zlog_ref(const struct xref_logmsg *xref,
  86                             const char *fmt, ...)
  87 {
  88         va_list ap;
  89
  90         va_start(ap, fmt);
  91         vzlogx(xref, xref->priority, fmt, ap);
  92         va_end(ap);
  93 }
  94
  95 #define _zlog_ecref(ec_, prio, msg, ...)                                       \
  96         do {                                                                   \
  97                 static struct xrefdata _xrefdata = {                           \
  98                         .xref = NULL,                                          \
  99                         .uid = {},                                             \
 100                         .hashstr = (msg),                                      \
 101                         .hashu32 = {(prio), (ec_)},                            \
 102                 };                                                             \
 103                 static const struct xref_logmsg _xref __attribute__(           \
 104                         (used)) = {                                            \
 105                         .xref = XREF_INIT(XREFT_LOGMSG, &_xrefdata, __func__), \
 106                         .fmtstring = (msg),                                    \
 107                         .priority = (prio),                                    \
 108                         .ec = (ec_),                                           \
 109                         .args = (#__VA_ARGS__),                                \
 110                 };                                                             \
 111                 XREF_LINK(_xref.xref);                                         \
 112                 zlog_ref(&_xref, (msg), ##__VA_ARGS__);                        \
 113         } while (0)
 114
 115 #define zlog_err(...)    _zlog_ecref(0, LOG_ERR, __VA_ARGS__)
 116 #define zlog_warn(...)   _zlog_ecref(0, LOG_WARNING, __VA_ARGS__)
 117 #define zlog_info(...)   _zlog_ecref(0, LOG_INFO, __VA_ARGS__)
 118 #define zlog_notice(...) _zlog_ecref(0, LOG_NOTICE, __VA_ARGS__)
 119 #define zlog_debug(...)  _zlog_ecref(0, LOG_DEBUG, __VA_ARGS__)
 120
 121 #define flog_err(ferr_id, format, ...)                                         \
 122         _zlog_ecref(ferr_id, LOG_ERR, format, ## __VA_ARGS__)
 123 #define flog_warn(ferr_id, format, ...)                                        \
 124         _zlog_ecref(ferr_id, LOG_WARNING, format, ## __VA_ARGS__)
 125
 126 #define flog_err_sys(ferr_id, format, ...)                                     \
 127         _zlog_ecref(ferr_id, LOG_ERR, format, ## __VA_ARGS__)
 128
 129 extern void zlog_sigsafe(const char *text, size_t len);
 130
 131 /* extra priority value to disable a target without deleting it */
 132 #define ZLOG_DISABLED   (LOG_EMERG-1)
 133
 134 /* zlog_msg encapsulates a particular logging call from somewhere in the code.
 135  * The same struct is passed around to all zlog_targets.
 136  *
 137  * This is used to defer formatting the log message until it is actually
 138  * requested by one of the targets.  If none of the targets needs the message
 139  * formatted, the formatting call is avoided entirely.
 140  *
 141  * This struct is opaque / private to the core zlog code.  Logging targets
 142  * should use zlog_msg_* functions to get text / timestamps / ... for a
 143  * message.
 144  */
 145
 146 struct zlog_msg;
 147
 148 extern int zlog_msg_prio(struct zlog_msg *msg);
 149 extern const struct xref_logmsg *zlog_msg_xref(struct zlog_msg *msg);
 150
 151 /* text is NOT \0 terminated; instead there is a \n after textlen since the
 152  * logging targets would jump extra hoops otherwise for a single byte.  (the
 153  * \n is not included in textlen)
 154  *
 155  * calling this with NULL textlen is likely wrong.
 156  * use  "%.*s", (int)textlen, text  when passing to printf-like functions
 157  */
 158 extern const char *zlog_msg_text(struct zlog_msg *msg, size_t *textlen);
 159
 160 extern void zlog_msg_args(struct zlog_msg *msg, size_t *hdrlen,
 161                           size_t *n_argpos, const struct fmt_outpos **argpos);
 162
 163 /* timestamp formatting control flags */
 164
 165 /* sub-second digit count */
 166 #define ZLOG_TS_PREC            0xfU
 167
 168 /* 8601:   0000-00-00T00:00:00Z      (if used with ZLOG_TS_UTC)
 169  *         0000-00-00T00:00:00+00:00 (otherwise)
 170  * Legacy: 0000/00/00 00:00:00       (no TZ indicated!)
 171  */
 172 #define ZLOG_TS_ISO8601         (1 << 8)
 173 #define ZLOG_TS_LEGACY          (1 << 9)
 174
 175 /* default is local time zone */
 176 #define ZLOG_TS_UTC             (1 << 10)
 177
 178 extern size_t zlog_msg_ts(struct zlog_msg *msg, struct fbuf *out,
 179                           uint32_t flags);
 180
 181 /* "mmm dd hh:mm:ss" for RFC3164 syslog.  Only ZLOG_TS_UTC for flags. */
 182 extern size_t zlog_msg_ts_3164(struct zlog_msg *msg, struct fbuf *out,
 183                                uint32_t flags);
 184
 185 /* currently just returns the current PID/TID since we never write another
 186  * thread's messages
 187  */
 188 extern void zlog_msg_pid(struct zlog_msg *msg, intmax_t *pid, intmax_t *tid);
 189
 190 /* This list & struct implements the actual logging targets.  It is accessed
 191  * lock-free from all threads, and thus MUST only be changed atomically, i.e.
 192  * RCU.
 193  *
 194  * Since there's no atomic replace, the replacement action is an add followed
 195  * by a delete.  This means that during logging config changes, log messages
 196  * may be duplicated in the log target that is being changed.  The old entry
 197  * being changed MUST also at the very least not crash or do other stupid
 198  * things.
 199  *
 200  * This list and struct are NOT related to config.  Logging config is kept
 201  * separately, and results in creating appropriate zlog_target(s) to realize
 202  * the config.  Log targets may also be created from varying sources, e.g.
 203  * command line options, or VTY commands ("log monitor").
 204  *
 205  * struct zlog_target is intended to be embedded into a larger structure that
 206  * contains additional field for the specific logging target, e.g. an fd or
 207  * additional options.  It MUST be the first field in that larger struct.
 208  */
 209
 210 PREDECL_ATOMLIST(zlog_targets);
 211 struct zlog_target {
 212         struct zlog_targets_item head;
 213
 214         int prio_min;
 215
 216         void (*logfn)(struct zlog_target *zt, struct zlog_msg *msg[],
 217                       size_t nmsgs);
 218
 219         /* for crash handlers, set to NULL if log target can't write crash logs
 220          * without possibly deadlocking (AS-Safe)
 221          *
 222          * text is not \0 terminated & split up into lines (e.g. no \n)
 223          */
 224         void (*logfn_sigsafe)(struct zlog_target *zt, const char *text,
 225                               size_t len);
 226
 227         struct rcu_head rcu_head;
 228 };
 229
 230 /* make a copy for RCUpdating.  oldzt may be NULL to allocate a fresh one. */
 231 extern struct zlog_target *zlog_target_clone(struct memtype *mt,
 232                                              struct zlog_target *oldzt,
 233                                              size_t size);
 234
 235 /* update the zlog_targets list;  both oldzt and newzt may be NULL.  You
 236  * still need to zlog_target_free() the old target afterwards if it wasn't
 237  * NULL.
 238  *
 239  * Returns oldzt so you can zlog_target_free(zlog_target_replace(old, new));
 240  * (Some log targets may need extra cleanup inbetween, but remember the old
 241  * target MUST remain functional until the end of the current RCU cycle.)
 242  */
 243 extern struct zlog_target *zlog_target_replace(struct zlog_target *oldzt,
 244                                                struct zlog_target *newzt);
 245
 246 /* Mostly for symmetry for zlog_target_clone(), just rcu_free() internally. */
 247 #define zlog_target_free(mt, zt) \
 248         rcu_free(mt, zt, rcu_head)
 249
 250 extern void zlog_init(const char *progname, const char *protoname,
 251                       unsigned short instance, uid_t uid, gid_t gid);
 252 DECLARE_HOOK(zlog_init, (const char *progname, const char *protoname,
 253                          unsigned short instance, uid_t uid, gid_t gid),
 254                         (progname, protoname, instance, uid, gid));
 255
 256 extern void zlog_fini(void);
 257 DECLARE_KOOH(zlog_fini, (), ());
 258
 259 extern void zlog_set_prefix_ec(bool enable);
 260 extern bool zlog_get_prefix_ec(void);
 261 extern void zlog_set_prefix_xid(bool enable);
 262 extern bool zlog_get_prefix_xid(void);
 263
 264 /* for tools & test programs, i.e. anything not a daemon.
 265  * (no cleanup needed at exit)
 266  */
 267 extern void zlog_aux_init(const char *prefix, int prio_min);
 268 DECLARE_HOOK(zlog_aux_init, (const char *prefix, int prio_min),
 269                             (prefix, prio_min));
 270
 271 extern void zlog_startup_end(void);
 272
 273 extern void zlog_tls_buffer_init(void);
 274 extern void zlog_tls_buffer_flush(void);
 275 extern void zlog_tls_buffer_fini(void);
 276
 277 /* Enable or disable 'immediate' output - default is to buffer messages. */
 278 extern void zlog_set_immediate(bool set_p);
 279
 280 extern const char *zlog_priority_str(int priority);
 281
 282 #ifdef __cplusplus
 283 }
 284 #endif
 285
 286 #endif /* _FRR_ZLOG_H */