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basic: Move log context functions to log-context.h

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This commit is contained in:
Daan De Meyer
2025-04-18 11:57:33 +02:00
parent 40d60725ec
commit a4bff6ef8e
10 changed files with 318 additions and 288 deletions
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src/basic/log-context.c
+180
View File
@@ -0,0 +1,180 @@
/* SPDX-License-Identifier: LGPL-2.1-or-later */
#include <threads.h>
#include "env-util.h"
#include "iovec-util.h"
#include "log.h"
#include "log-context.h"
#include "strv.h"
static int saved_log_context_enabled = -1;
thread_local LIST_HEAD(LogContext, _log_context) = NULL;
thread_local size_t _log_context_num_fields = 0;
bool log_context_enabled(void) {
int r;
if (log_get_max_level() == LOG_DEBUG)
return true;
if (saved_log_context_enabled >= 0)
return saved_log_context_enabled;
r = secure_getenv_bool("SYSTEMD_ENABLE_LOG_CONTEXT");
if (r < 0 && r != -ENXIO)
log_debug_errno(r, "Failed to parse $SYSTEMD_ENABLE_LOG_CONTEXT, ignoring: %m");
saved_log_context_enabled = r > 0;
return saved_log_context_enabled;
}
static LogContext* log_context_attach(LogContext *c) {
assert(c);
_log_context_num_fields += strv_length(c->fields);
_log_context_num_fields += c->n_input_iovec;
_log_context_num_fields += !!c->key;
return LIST_PREPEND(ll, _log_context, c);
}
static LogContext* log_context_detach(LogContext *c) {
if (!c)
return NULL;
assert(_log_context_num_fields >= strv_length(c->fields) + c->n_input_iovec +!!c->key);
_log_context_num_fields -= strv_length(c->fields);
_log_context_num_fields -= c->n_input_iovec;
_log_context_num_fields -= !!c->key;
LIST_REMOVE(ll, _log_context, c);
return NULL;
}
LogContext* log_context_new(const char *key, const char *value) {
assert(key);
assert(endswith(key, "="));
assert(value);
LIST_FOREACH(ll, i, _log_context)
if (i->key == key && i->value == value)
return log_context_ref(i);
LogContext *c = new(LogContext, 1);
if (!c)
return NULL;
*c = (LogContext) {
.n_ref = 1,
.key = (char *) key,
.value = (char *) value,
};
return log_context_attach(c);
}
LogContext* log_context_new_strv(char **fields, bool owned) {
if (!fields)
return NULL;
LIST_FOREACH(ll, i, _log_context)
if (i->fields == fields) {
assert(!owned);
return log_context_ref(i);
}
LogContext *c = new(LogContext, 1);
if (!c)
return NULL;
*c = (LogContext) {
.n_ref = 1,
.fields = fields,
.owned = owned,
};
return log_context_attach(c);
}
LogContext* log_context_new_iov(struct iovec *input_iovec, size_t n_input_iovec, bool owned) {
if (!input_iovec || n_input_iovec == 0)
return NULL;
LIST_FOREACH(ll, i, _log_context)
if (i->input_iovec == input_iovec && i->n_input_iovec == n_input_iovec) {
assert(!owned);
return log_context_ref(i);
}
LogContext *c = new(LogContext, 1);
if (!c)
return NULL;
*c = (LogContext) {
.n_ref = 1,
.input_iovec = input_iovec,
.n_input_iovec = n_input_iovec,
.owned = owned,
};
return log_context_attach(c);
}
static LogContext* log_context_free(LogContext *c) {
if (!c)
return NULL;
log_context_detach(c);
if (c->owned) {
strv_free(c->fields);
iovec_array_free(c->input_iovec, c->n_input_iovec);
free(c->key);
free(c->value);
}
return mfree(c);
}
DEFINE_TRIVIAL_REF_UNREF_FUNC(LogContext, log_context, log_context_free);
LogContext* log_context_new_strv_consume(char **fields) {
LogContext *c = log_context_new_strv(fields, /*owned=*/ true);
if (!c)
strv_free(fields);
return c;
}
LogContext* log_context_new_iov_consume(struct iovec *input_iovec, size_t n_input_iovec) {
LogContext *c = log_context_new_iov(input_iovec, n_input_iovec, /*owned=*/ true);
if (!c)
iovec_array_free(input_iovec, n_input_iovec);
return c;
}
LogContext* log_context_head(void) {
return _log_context;
}
size_t log_context_num_contexts(void) {
size_t n = 0;
LIST_FOREACH(ll, c, _log_context)
n++;
return n;
}
size_t log_context_num_fields(void) {
return _log_context_num_fields;
}
void _reset_log_level(int *saved_log_level) {
assert(saved_log_level);
log_set_max_level(*saved_log_level);
}
src/basic/log-context.h
+127
View File
@@ -0,0 +1,127 @@
/* SPDX-License-Identifier: LGPL-2.1-or-later */
#pragma once
#include <stdbool.h>
#include <stddef.h>
#include "macro.h"
/*
* The log context allows attaching extra metadata to log messages written to the journal via log.h. We keep
* track of a thread local log context onto which we can push extra metadata fields that should be logged.
*
* LOG_CONTEXT_PUSH() will add the provided field to the log context and will remove it again when the
* current block ends. LOG_CONTEXT_PUSH_STRV() will do the same but for all fields in the given strv.
* LOG_CONTEXT_PUSHF() is like LOG_CONTEXT_PUSH() but takes a format string and arguments.
*
* Using the macros is as simple as putting them anywhere inside a block to add a field to all following log
* messages logged from inside that block.
*
* void myfunction(...) {
* ...
*
* LOG_CONTEXT_PUSHF("MYMETADATA=%s", "abc");
*
* // Every journal message logged will now have the MYMETADATA=abc
* // field included.
* }
*
* One special case to note is async code, where we use callbacks that are invoked to continue processing
* when some event occurs. For async code, there's usually an associated "userdata" struct containing all the
* information associated with the async operation. In this "userdata" struct, we can store a log context
* allocated with log_context_new() and freed with log_context_free(). We can then add and remove fields to
* the `fields` member of the log context object and all those fields will be logged along with each log
* message.
*/
struct iovec;
typedef struct LogContext {
unsigned n_ref;
/* Depending on which destructor is used (log_context_free() or log_context_detach()) the memory
* referenced by this is freed or not */
char **fields;
struct iovec *input_iovec;
size_t n_input_iovec;
char *key;
char *value;
bool owned;
LIST_FIELDS(struct LogContext, ll);
} LogContext;
bool log_context_enabled(void);
LogContext* log_context_new(const char *key, const char *value);
LogContext* log_context_new_strv(char **fields, bool owned);
LogContext* log_context_new_iov(struct iovec *input_iovec, size_t n_input_iovec, bool owned);
/* Same as log_context_new(), but frees the given fields strv/iovec on failure. */
LogContext* log_context_new_strv_consume(char **fields);
LogContext* log_context_new_iov_consume(struct iovec *input_iovec, size_t n_input_iovec);
LogContext *log_context_ref(LogContext *c);
LogContext *log_context_unref(LogContext *c);
DEFINE_TRIVIAL_CLEANUP_FUNC(LogContext*, log_context_unref);
/* Returns the head of the log context list. */
LogContext* log_context_head(void);
/* Returns the number of attached log context objects. */
size_t log_context_num_contexts(void);
/* Returns the number of fields in all attached log contexts. */
size_t log_context_num_fields(void);
void _reset_log_level(int *saved_log_level);
#define LOG_CONTEXT_SET_LOG_LEVEL(level) \
_cleanup_(_reset_log_level) _unused_ int _saved_log_level_ = log_set_max_level(level);
#define LOG_CONTEXT_PUSH(...) \
LOG_CONTEXT_PUSH_STRV(STRV_MAKE(__VA_ARGS__))
#define LOG_CONTEXT_PUSHF(...) \
LOG_CONTEXT_PUSH(snprintf_ok((char[LINE_MAX]) {}, LINE_MAX, __VA_ARGS__))
#define _LOG_CONTEXT_PUSH_KEY_VALUE(key, value, c) \
_unused_ _cleanup_(log_context_unrefp) LogContext *c = log_context_new(key, value);
#define LOG_CONTEXT_PUSH_KEY_VALUE(key, value) \
_LOG_CONTEXT_PUSH_KEY_VALUE(key, value, UNIQ_T(c, UNIQ))
#define _LOG_CONTEXT_PUSH_STRV(strv, c) \
_unused_ _cleanup_(log_context_unrefp) LogContext *c = log_context_new_strv(strv, /*owned=*/ false);
#define LOG_CONTEXT_PUSH_STRV(strv) \
_LOG_CONTEXT_PUSH_STRV(strv, UNIQ_T(c, UNIQ))
#define _LOG_CONTEXT_PUSH_IOV(input_iovec, n_input_iovec, c) \
_unused_ _cleanup_(log_context_unrefp) LogContext *c = log_context_new_iov(input_iovec, n_input_iovec, /*owned=*/ false);
#define LOG_CONTEXT_PUSH_IOV(input_iovec, n_input_iovec) \
_LOG_CONTEXT_PUSH_IOV(input_iovec, n_input_iovec, UNIQ_T(c, UNIQ))
/* LOG_CONTEXT_CONSUME_STR()/LOG_CONTEXT_CONSUME_STRV()/LOG_CONTEXT_CONSUME_IOV() are identical to
* LOG_CONTEXT_PUSH_STR()/LOG_CONTEXT_PUSH_STRV()/LOG_CONTEXT_PUSH_IOV() except they take ownership of the
* given str/strv argument.
*/
#define _LOG_CONTEXT_CONSUME_STR(s, c, strv) \
_unused_ _cleanup_strv_free_ strv = strv_new(s); \
if (!strv) \
free(s); \
_unused_ _cleanup_(log_context_unrefp) LogContext *c = log_context_new_strv_consume(TAKE_PTR(strv))
#define LOG_CONTEXT_CONSUME_STR(s) \
_LOG_CONTEXT_CONSUME_STR(s, UNIQ_T(c, UNIQ), UNIQ_T(sv, UNIQ))
#define _LOG_CONTEXT_CONSUME_STRV(strv, c) \
_unused_ _cleanup_(log_context_unrefp) LogContext *c = log_context_new_strv_consume(strv);
#define LOG_CONTEXT_CONSUME_STRV(strv) \
_LOG_CONTEXT_CONSUME_STRV(strv, UNIQ_T(c, UNIQ))
#define _LOG_CONTEXT_CONSUME_IOV(input_iovec, n_input_iovec, c) \
_unused_ _cleanup_(log_context_unrefp) LogContext *c = log_context_new_iov_consume(input_iovec, n_input_iovec);
#define LOG_CONTEXT_CONSUME_IOV(input_iovec, n_input_iovec) \
_LOG_CONTEXT_CONSUME_IOV(input_iovec, n_input_iovec, UNIQ_T(c, UNIQ))
src/basic/log.c
+5 -179
View File
@@ -25,6 +25,7 @@
#include "format-util.h"
#include "iovec-util.h"
#include "log.h"
#include "log-context.h"
#include "macro.h"
#include "missing_syscall.h"
#include "parse-util.h"
@@ -82,22 +83,6 @@ static bool assert_return_is_critical = BUILD_MODE_DEVELOPER;
* use here. */
static char *log_abort_msg = NULL;
typedef struct LogContext {
unsigned n_ref;
/* Depending on which destructor is used (log_context_free() or log_context_detach()) the memory
* referenced by this is freed or not */
char **fields;
struct iovec *input_iovec;
size_t n_input_iovec;
char *key;
char *value;
bool owned;
LIST_FIELDS(struct LogContext, ll);
} LogContext;
static thread_local LIST_HEAD(LogContext, _log_context) = NULL;
static thread_local size_t _log_context_num_fields = 0;
static thread_local const char *log_prefix = NULL;
#if LOG_MESSAGE_VERIFICATION || defined(__COVERITY__)
@@ -697,7 +682,7 @@ static void log_do_context(struct iovec *iovec, size_t iovec_len, size_t *n) {
assert(iovec);
assert(n);
LIST_FOREACH(ll, c, _log_context) {
LIST_FOREACH(ll, c, log_context_head()) {
STRV_FOREACH(s, c->fields) {
if (*n + 2 >= iovec_len)
return;
@@ -747,7 +732,7 @@ static int write_to_journal(
if (LOG_PRI(level) > log_target_max_level[LOG_TARGET_JOURNAL])
return 0;
iovec_len = MIN(6 + _log_context_num_fields * 3, IOVEC_MAX);
iovec_len = MIN(6 + log_context_num_fields() * 3, IOVEC_MAX);
iovec = newa(struct iovec, iovec_len);
log_do_header(header, sizeof(header), level, error, file, line, func, object_field, object, extra_field, extra);
@@ -1099,7 +1084,7 @@ int log_struct_internal(
int r;
bool fallback = false;
iovec_len = MIN(17 + _log_context_num_fields * 3, IOVEC_MAX);
iovec_len = MIN(17 + log_context_num_fields() * 3, IOVEC_MAX);
iovec = newa(struct iovec, iovec_len);
/* If the journal is available do structured logging.
@@ -1200,7 +1185,7 @@ int log_struct_iovec_internal(
struct iovec *iovec;
size_t n = 0, iovec_len;
iovec_len = MIN(1 + n_input_iovec * 2 + _log_context_num_fields * 3, IOVEC_MAX);
iovec_len = MIN(1 + n_input_iovec * 2 + log_context_num_fields() * 3, IOVEC_MAX);
iovec = newa(struct iovec, iovec_len);
log_do_header(header, sizeof(header), level, error, file, line, func, NULL, NULL, NULL, NULL);
@@ -1811,162 +1796,3 @@ const char* _log_set_prefix(const char *prefix, bool force) {
return old;
}
static int saved_log_context_enabled = -1;
bool log_context_enabled(void) {
int r;
if (log_get_max_level() == LOG_DEBUG)
return true;
if (saved_log_context_enabled >= 0)
return saved_log_context_enabled;
r = secure_getenv_bool("SYSTEMD_ENABLE_LOG_CONTEXT");
if (r < 0 && r != -ENXIO)
log_debug_errno(r, "Failed to parse $SYSTEMD_ENABLE_LOG_CONTEXT, ignoring: %m");
saved_log_context_enabled = r > 0;
return saved_log_context_enabled;
}
static LogContext* log_context_attach(LogContext *c) {
assert(c);
_log_context_num_fields += strv_length(c->fields);
_log_context_num_fields += c->n_input_iovec;
_log_context_num_fields += !!c->key;
return LIST_PREPEND(ll, _log_context, c);
}
static LogContext* log_context_detach(LogContext *c) {
if (!c)
return NULL;
assert(_log_context_num_fields >= strv_length(c->fields) + c->n_input_iovec +!!c->key);
_log_context_num_fields -= strv_length(c->fields);
_log_context_num_fields -= c->n_input_iovec;
_log_context_num_fields -= !!c->key;
LIST_REMOVE(ll, _log_context, c);
return NULL;
}
LogContext* log_context_new(const char *key, const char *value) {
assert(key);
assert(endswith(key, "="));
assert(value);
LIST_FOREACH(ll, i, _log_context)
if (i->key == key && i->value == value)
return log_context_ref(i);
LogContext *c = new(LogContext, 1);
if (!c)
return NULL;
*c = (LogContext) {
.n_ref = 1,
.key = (char *) key,
.value = (char *) value,
};
return log_context_attach(c);
}
LogContext* log_context_new_strv(char **fields, bool owned) {
if (!fields)
return NULL;
LIST_FOREACH(ll, i, _log_context)
if (i->fields == fields) {
assert(!owned);
return log_context_ref(i);
}
LogContext *c = new(LogContext, 1);
if (!c)
return NULL;
*c = (LogContext) {
.n_ref = 1,
.fields = fields,
.owned = owned,
};
return log_context_attach(c);
}
LogContext* log_context_new_iov(struct iovec *input_iovec, size_t n_input_iovec, bool owned) {
if (!input_iovec || n_input_iovec == 0)
return NULL;
LIST_FOREACH(ll, i, _log_context)
if (i->input_iovec == input_iovec && i->n_input_iovec == n_input_iovec) {
assert(!owned);
return log_context_ref(i);
}
LogContext *c = new(LogContext, 1);
if (!c)
return NULL;
*c = (LogContext) {
.n_ref = 1,
.input_iovec = input_iovec,
.n_input_iovec = n_input_iovec,
.owned = owned,
};
return log_context_attach(c);
}
static LogContext* log_context_free(LogContext *c) {
if (!c)
return NULL;
log_context_detach(c);
if (c->owned) {
strv_free(c->fields);
iovec_array_free(c->input_iovec, c->n_input_iovec);
free(c->key);
free(c->value);
}
return mfree(c);
}
DEFINE_TRIVIAL_REF_UNREF_FUNC(LogContext, log_context, log_context_free);
LogContext* log_context_new_strv_consume(char **fields) {
LogContext *c = log_context_new_strv(fields, /*owned=*/ true);
if (!c)
strv_free(fields);
return c;
}
LogContext* log_context_new_iov_consume(struct iovec *input_iovec, size_t n_input_iovec) {
LogContext *c = log_context_new_iov(input_iovec, n_input_iovec, /*owned=*/ true);
if (!c)
iovec_array_free(input_iovec, n_input_iovec);
return c;
}
size_t log_context_num_contexts(void) {
size_t n = 0;
LIST_FOREACH(ll, c, _log_context)
n++;
return n;
}
size_t log_context_num_fields(void) {
return _log_context_num_fields;
}
src/basic/log.h
-109
View File
@@ -411,112 +411,3 @@ static inline const char* _log_unset_prefixp(const char **p) {
#define LOG_SET_PREFIX(prefix) \
_cleanup_(_log_unset_prefixp) _unused_ const char *CONCATENATE(_cleanup_log_unset_prefix_, UNIQ) = _log_set_prefix(prefix, false);
/*
* The log context allows attaching extra metadata to log messages written to the journal via log.h. We keep
* track of a thread local log context onto which we can push extra metadata fields that should be logged.
*
* LOG_CONTEXT_PUSH() will add the provided field to the log context and will remove it again when the
* current block ends. LOG_CONTEXT_PUSH_STRV() will do the same but for all fields in the given strv.
* LOG_CONTEXT_PUSHF() is like LOG_CONTEXT_PUSH() but takes a format string and arguments.
*
* Using the macros is as simple as putting them anywhere inside a block to add a field to all following log
* messages logged from inside that block.
*
* void myfunction(...) {
* ...
*
* LOG_CONTEXT_PUSHF("MYMETADATA=%s", "abc");
*
* // Every journal message logged will now have the MYMETADATA=abc
* // field included.
* }
*
* One special case to note is async code, where we use callbacks that are invoked to continue processing
* when some event occurs. For async code, there's usually an associated "userdata" struct containing all the
* information associated with the async operation. In this "userdata" struct, we can store a log context
* allocated with log_context_new() and freed with log_context_free(). We can then add and remove fields to
* the `fields` member of the log context object and all those fields will be logged along with each log
* message.
*/
typedef struct LogContext LogContext;
bool log_context_enabled(void);
LogContext* log_context_new(const char *key, const char *value);
LogContext* log_context_new_strv(char **fields, bool owned);
LogContext* log_context_new_iov(struct iovec *input_iovec, size_t n_input_iovec, bool owned);
/* Same as log_context_new(), but frees the given fields strv/iovec on failure. */
LogContext* log_context_new_strv_consume(char **fields);
LogContext* log_context_new_iov_consume(struct iovec *input_iovec, size_t n_input_iovec);
LogContext *log_context_ref(LogContext *c);
LogContext *log_context_unref(LogContext *c);
DEFINE_TRIVIAL_CLEANUP_FUNC(LogContext*, log_context_unref);
/* Returns the number of attached log context objects. */
size_t log_context_num_contexts(void);
/* Returns the number of fields in all attached log contexts. */
size_t log_context_num_fields(void);
static inline void _reset_log_level(int *saved_log_level) {
assert(saved_log_level);
log_set_max_level(*saved_log_level);
}
#define LOG_CONTEXT_SET_LOG_LEVEL(level) \
_cleanup_(_reset_log_level) _unused_ int _saved_log_level_ = log_set_max_level(level);
#define LOG_CONTEXT_PUSH(...) \
LOG_CONTEXT_PUSH_STRV(STRV_MAKE(__VA_ARGS__))
#define LOG_CONTEXT_PUSHF(...) \
LOG_CONTEXT_PUSH(snprintf_ok((char[LINE_MAX]) {}, LINE_MAX, __VA_ARGS__))
#define _LOG_CONTEXT_PUSH_KEY_VALUE(key, value, c) \
_unused_ _cleanup_(log_context_unrefp) LogContext *c = log_context_new(key, value);
#define LOG_CONTEXT_PUSH_KEY_VALUE(key, value) \
_LOG_CONTEXT_PUSH_KEY_VALUE(key, value, UNIQ_T(c, UNIQ))
#define _LOG_CONTEXT_PUSH_STRV(strv, c) \
_unused_ _cleanup_(log_context_unrefp) LogContext *c = log_context_new_strv(strv, /*owned=*/ false);
#define LOG_CONTEXT_PUSH_STRV(strv) \
_LOG_CONTEXT_PUSH_STRV(strv, UNIQ_T(c, UNIQ))
#define _LOG_CONTEXT_PUSH_IOV(input_iovec, n_input_iovec, c) \
_unused_ _cleanup_(log_context_unrefp) LogContext *c = log_context_new_iov(input_iovec, n_input_iovec, /*owned=*/ false);
#define LOG_CONTEXT_PUSH_IOV(input_iovec, n_input_iovec) \
_LOG_CONTEXT_PUSH_IOV(input_iovec, n_input_iovec, UNIQ_T(c, UNIQ))
/* LOG_CONTEXT_CONSUME_STR()/LOG_CONTEXT_CONSUME_STRV()/LOG_CONTEXT_CONSUME_IOV() are identical to
* LOG_CONTEXT_PUSH_STR()/LOG_CONTEXT_PUSH_STRV()/LOG_CONTEXT_PUSH_IOV() except they take ownership of the
* given str/strv argument.
*/
#define _LOG_CONTEXT_CONSUME_STR(s, c, strv) \
_unused_ _cleanup_strv_free_ strv = strv_new(s); \
if (!strv) \
free(s); \
_unused_ _cleanup_(log_context_unrefp) LogContext *c = log_context_new_strv_consume(TAKE_PTR(strv))
#define LOG_CONTEXT_CONSUME_STR(s) \
_LOG_CONTEXT_CONSUME_STR(s, UNIQ_T(c, UNIQ), UNIQ_T(sv, UNIQ))
#define _LOG_CONTEXT_CONSUME_STRV(strv, c) \
_unused_ _cleanup_(log_context_unrefp) LogContext *c = log_context_new_strv_consume(strv);
#define LOG_CONTEXT_CONSUME_STRV(strv) \
_LOG_CONTEXT_CONSUME_STRV(strv, UNIQ_T(c, UNIQ))
#define _LOG_CONTEXT_CONSUME_IOV(input_iovec, n_input_iovec, c) \
_unused_ _cleanup_(log_context_unrefp) LogContext *c = log_context_new_iov_consume(input_iovec, n_input_iovec);
#define LOG_CONTEXT_CONSUME_IOV(input_iovec, n_input_iovec) \
_LOG_CONTEXT_CONSUME_IOV(input_iovec, n_input_iovec, UNIQ_T(c, UNIQ))
src/basic/meson.build
+1
View File
@@ -58,6 +58,7 @@ basic_sources = files(
'locale-util.c',
'lock-util.c',
'log.c',
'log-context.c',
'login-util.c',
'keyring-util.c',
'memfd-util.c',