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Systemd/src/shared/conf-parser.h
Lennart Poettering 4f9ff96a55 conf-parser: return mtime in config_parse() and friends 
This is a follow-up for 9f83091e3c.

Instead of reading the mtime off the configuration files after reading,
let's do so before reading, but with the fd we read the data from. This
is not only cleaner (as it allows us to save one stat()), but also has
the benefit that we'll detect changes that happen while we read the
files.

This also reworks unit file drop-ins to use the common code for
determining drop-in mtime, instead of reading system clock for that.
2020-06-02 19:32:20 +02:00

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/* SPDX-License-Identifier: LGPL-2.1+ */
#pragma once
#include <errno.h>
#include <stdbool.h>
#include <stddef.h>
#include <stdio.h>
#include <syslog.h>
#include "alloc-util.h"
#include "log.h"
#include "macro.h"
#include "time-util.h"
/* An abstract parser for simple, line based, shallow configuration files consisting of variable assignments only. */
typedef enum ConfigParseFlags {
CONFIG_PARSE_RELAXED = 1 << 0, /* Do not warn about unknown non-extension fields */
CONFIG_PARSE_ALLOW_INCLUDE = 1 << 1, /* Allow the deprecated .include stanza */
CONFIG_PARSE_WARN = 1 << 2, /* Emit non-debug messages */
} ConfigParseFlags;
/* Argument list for parsers of specific configuration settings. */
#define CONFIG_PARSER_ARGUMENTS \
const char *unit, \
const char *filename, \
unsigned line, \
const char *section, \
unsigned section_line, \
const char *lvalue, \
int ltype, \
const char *rvalue, \
void *data, \
void *userdata
/* Prototype for a parser for a specific configuration setting */
typedef int (*ConfigParserCallback)(CONFIG_PARSER_ARGUMENTS);
/* A macro declaring the a function prototype, following the typedef above, simply because it's so cumbersomely long
* otherwise. (And current emacs gets irritatingly slow when editing files that contain lots of very long function
* prototypes on the same screen…) */
#define CONFIG_PARSER_PROTOTYPE(name) int name(CONFIG_PARSER_ARGUMENTS)
/* Wraps information for parsing a specific configuration variable, to
* be stored in a simple array */
typedef struct ConfigTableItem {
const char *section; /* Section */
const char *lvalue; /* Name of the variable */
ConfigParserCallback parse; /* Function that is called to parse the variable's value */
int ltype; /* Distinguish different variables passed to the same callback */
void *data; /* Where to store the variable's data */
} ConfigTableItem;
/* Wraps information for parsing a specific configuration variable, to
* be stored in a gperf perfect hashtable */
typedef struct ConfigPerfItem {
const char *section_and_lvalue; /* Section + "." + name of the variable */
ConfigParserCallback parse; /* Function that is called to parse the variable's value */
int ltype; /* Distinguish different variables passed to the same callback */
size_t offset; /* Offset where to store data, from the beginning of userdata */
} ConfigPerfItem;
/* Prototype for a low-level gperf lookup function */
typedef const ConfigPerfItem* (*ConfigPerfItemLookup)(const char *section_and_lvalue, unsigned length);
/* Prototype for a generic high-level lookup function */
typedef int (*ConfigItemLookup)(
const void *table,
const char *section,
const char *lvalue,
ConfigParserCallback *func,
int *ltype,
void **data,
void *userdata);
/* Linear table search implementation of ConfigItemLookup, based on
* ConfigTableItem arrays */
int config_item_table_lookup(const void *table, const char *section, const char *lvalue, ConfigParserCallback *func, int *ltype, void **data, void *userdata);
/* gperf implementation of ConfigItemLookup, based on gperf
* ConfigPerfItem tables */
int config_item_perf_lookup(const void *table, const char *section, const char *lvalue, ConfigParserCallback *func, int *ltype, void **data, void *userdata);
int config_parse(
const char *unit,
const char *filename,
FILE *f,
const char *sections, /* nulstr */
ConfigItemLookup lookup,
const void *table,
ConfigParseFlags flags,
void *userdata,
usec_t *ret_mtime); /* possibly NULL */
int config_parse_many_nulstr(
const char *conf_file, /* possibly NULL */
const char *conf_file_dirs, /* nulstr */
const char *sections, /* nulstr */
ConfigItemLookup lookup,
const void *table,
ConfigParseFlags flags,
void *userdata,
usec_t *ret_mtime); /* possibly NULL */
int config_parse_many(
const char *conf_file, /* possibly NULL */
const char* const* conf_file_dirs,
const char *dropin_dirname,
const char *sections, /* nulstr */
ConfigItemLookup lookup,
const void *table,
ConfigParseFlags flags,
void *userdata,
usec_t *ret_mtime); /* possibly NULL */
CONFIG_PARSER_PROTOTYPE(config_parse_int);
CONFIG_PARSER_PROTOTYPE(config_parse_unsigned);
CONFIG_PARSER_PROTOTYPE(config_parse_long);
CONFIG_PARSER_PROTOTYPE(config_parse_uint8);
CONFIG_PARSER_PROTOTYPE(config_parse_uint16);
CONFIG_PARSER_PROTOTYPE(config_parse_uint32);
CONFIG_PARSER_PROTOTYPE(config_parse_int32);
CONFIG_PARSER_PROTOTYPE(config_parse_uint64);
CONFIG_PARSER_PROTOTYPE(config_parse_double);
CONFIG_PARSER_PROTOTYPE(config_parse_iec_size);
CONFIG_PARSER_PROTOTYPE(config_parse_si_uint64);
CONFIG_PARSER_PROTOTYPE(config_parse_iec_uint64);
CONFIG_PARSER_PROTOTYPE(config_parse_bool);
CONFIG_PARSER_PROTOTYPE(config_parse_id128);
CONFIG_PARSER_PROTOTYPE(config_parse_tristate);
CONFIG_PARSER_PROTOTYPE(config_parse_string);
CONFIG_PARSER_PROTOTYPE(config_parse_path);
CONFIG_PARSER_PROTOTYPE(config_parse_strv);
CONFIG_PARSER_PROTOTYPE(config_parse_sec);
CONFIG_PARSER_PROTOTYPE(config_parse_sec_def_infinity);
CONFIG_PARSER_PROTOTYPE(config_parse_sec_def_unset);
CONFIG_PARSER_PROTOTYPE(config_parse_nsec);
CONFIG_PARSER_PROTOTYPE(config_parse_mode);
CONFIG_PARSER_PROTOTYPE(config_parse_warn_compat);
CONFIG_PARSER_PROTOTYPE(config_parse_log_facility);
CONFIG_PARSER_PROTOTYPE(config_parse_log_level);
CONFIG_PARSER_PROTOTYPE(config_parse_signal);
CONFIG_PARSER_PROTOTYPE(config_parse_personality);
CONFIG_PARSER_PROTOTYPE(config_parse_permille);
CONFIG_PARSER_PROTOTYPE(config_parse_ifname);
CONFIG_PARSER_PROTOTYPE(config_parse_ifnames);
CONFIG_PARSER_PROTOTYPE(config_parse_ip_port);
CONFIG_PARSER_PROTOTYPE(config_parse_mtu);
CONFIG_PARSER_PROTOTYPE(config_parse_rlimit);
CONFIG_PARSER_PROTOTYPE(config_parse_vlanprotocol);
typedef enum Disabled {
DISABLED_CONFIGURATION,
DISABLED_LEGACY,
DISABLED_EXPERIMENTAL,
} Disabled;
#define DEFINE_CONFIG_PARSE(function, parser, msg) \
CONFIG_PARSER_PROTOTYPE(function) { \
int *i = data, r; \
\
assert(filename); \
assert(lvalue); \
assert(rvalue); \
assert(data); \
\
r = parser(rvalue); \
if (r < 0) { \
log_syntax(unit, LOG_ERR, filename, line, r, \
msg ", ignoring: %s", rvalue); \
return 0; \
} \
\
*i = r; \
return 0; \
}
#define DEFINE_CONFIG_PARSE_PTR(function, parser, type, msg) \
CONFIG_PARSER_PROTOTYPE(function) { \
type *i = data; \
int r; \
\
assert(filename); \
assert(lvalue); \
assert(rvalue); \
assert(data); \
\
r = parser(rvalue, i); \
if (r < 0) \
log_syntax(unit, LOG_ERR, filename, line, r, \
msg ", ignoring: %s", rvalue); \
\
return 0; \
}
#define DEFINE_CONFIG_PARSE_ENUM(function, name, type, msg) \
CONFIG_PARSER_PROTOTYPE(function) { \
type *i = data, x; \
\
assert(filename); \
assert(lvalue); \
assert(rvalue); \
assert(data); \
\
x = name##_from_string(rvalue); \
if (x < 0) { \
log_syntax(unit, LOG_ERR, filename, line, 0, \
msg ", ignoring: %s", rvalue); \
return 0; \
} \
\
*i = x; \
return 0; \
}
#define DEFINE_CONFIG_PARSE_ENUM_WITH_DEFAULT(function, name, type, default_value, msg) \
CONFIG_PARSER_PROTOTYPE(function) { \
type *i = data, x; \
\
assert(filename); \
assert(lvalue); \
assert(rvalue); \
assert(data); \
\
if (isempty(rvalue)) { \
*i = default_value; \
return 0; \
} \
\
x = name##_from_string(rvalue); \
if (x < 0) { \
log_syntax(unit, LOG_ERR, filename, line, 0, \
msg ", ignoring: %s", rvalue); \
return 0; \
} \
\
*i = x; \
return 0; \
}
#define DEFINE_CONFIG_PARSE_ENUMV(function, name, type, invalid, msg) \
CONFIG_PARSER_PROTOTYPE(function) { \
type **enums = data, x, *ys; \
_cleanup_free_ type *xs = NULL; \
const char *word, *state; \
size_t l, i = 0; \
\
assert(filename); \
assert(lvalue); \
assert(rvalue); \
assert(data); \
\
xs = new0(type, 1); \
if (!xs) \
return -ENOMEM; \
\
*xs = invalid; \
\
FOREACH_WORD(word, l, rvalue, state) { \
_cleanup_free_ char *en = NULL; \
type *new_xs; \
\
en = strndup(word, l); \
if (!en) \
return -ENOMEM; \
\
if ((x = name##_from_string(en)) < 0) { \
log_syntax(unit, LOG_ERR, filename, line, 0, \
msg ", ignoring: %s", en); \
continue; \
} \
\
for (ys = xs; x != invalid && *ys != invalid; ys++) { \
if (*ys == x) { \
log_syntax(unit, LOG_NOTICE, filename, \
line, 0, \
"Duplicate entry, ignoring: %s", \
en); \
x = invalid; \
} \
} \
\
if (x == invalid) \
continue; \
\
*(xs + i) = x; \
new_xs = realloc(xs, (++i + 1) * sizeof(type)); \
if (new_xs) \
xs = new_xs; \
else \
return -ENOMEM; \
\
*(xs + i) = invalid; \
} \
\
free_and_replace(*enums, xs); \
return 0; \
}
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