dhcp-libutil.h

this is sample about DHCP-agent

/* $Header: /cvsroot/dhcp-agent/dhcp-agent/src/dhcp-libutil.h,v 1.29 2003/07/08 07:01:42 actmodern Exp $
 *
 * Copyright 2002 Thamer Alharbash
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 * notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 * notice, this list of conditions and the following disclaimer in
 * the documentation and/or other materials provided with the
 * distribution.
 * 3. The names of the authors may not be used to endorse or promote
 * products derived from this software without specific prior
 * written permission.
 *
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
 * 
 * External interface header file: include this to use the
 * utility library.
 *
 */

#ifndef DHCP_LIBUTIL_H
#define DHCP_LIBUTIL_H

/* types. */

/* conf parser types. */
typedef uint32_t command_code_t;
typedef uint32_t arg_len_t;
typedef uint32_t arg_type_t;
typedef uint8_t arg_symbol_t;

/* tokenizer types. */
typedef uint8_t token_t;

/* * * * * * * * * * *
 * Data structures.  *
 * * * * * * * * * * */

/* native data structures. */

typedef struct node {
    struct node *next;
    void *data;
} node_t;

typedef struct {
    node_t *head;
    node_t *tail;
    node_t *seek;
    int len;
} list_t;

/* string buffer object. */
typedef struct {
    size_t len;
    size_t capacity;
    char *buf;
} stringbuffer_t;

/* utility data structures. */

/* rtt object. */
typedef struct rtt {
    struct timeval timeout;
    time_t max_timeout;
    time_t start_time;
    time_t elapsed_time;
} rtt_t;

/* trigger object. */
typedef struct {
    uint32_t time_set;
    uint32_t seconds;
    uint32_t id;
} timer_trigger_t;

/* timer object. */
typedef struct {
    list_t *triggers;
    uint32_t current_id;
} timer_keeper_t;

/* parser object. */
typedef struct {
    FILE *fp;
    int line_no;
    stringbuffer_t *data_buff;
    token_t peek_value;
    uint8_t peeked;
} tokenizer_t;

/* varfile object. */
typedef struct {
    char *filename;
    tokenizer_t *tokenizer;
    stringbuffer_t *var_name;
    stringbuffer_t *var_val;
    uint8_t mode;
} varfile_t;

/* compiled directive. */
typedef struct {
    command_code_t command_code; /* the command code. */
    list_t *argument_types;      /* type of argument: need this to free up arguments later. */
    list_t *arguments;           /* argument data. */
} directive_t;

/* command syntax object. */
typedef struct {

    const command_code_t command_code;
    const char *command_name;

    const arg_len_t   argument_len;
    const char          ***argument_strings;
    const arg_type_t    *argument_types;
    const arg_symbol_t  **argument_symbols;

} command_t;

/* conf object. */
typedef struct {
    char *filename;
    tokenizer_t *tokenizer;
    const command_t **commands; /* list of permissible commands. */
    list_t *directives;
} conf_t;

/* prototypes. */

/* in case strdup is not available. */

# ifndef HAVE_STRDUP
extern char *strdup(char *s);
# endif                         /* HAVE_STRDUP */

/* messaging. */
extern void error_message(const char *func_name, const char *fmt, ...);
extern void fatal_message(const char *func_name, const char *fmt, ...);
extern void info_message(const char *fmt, ...);
extern void warn_message(char *fmt, ...);
extern void debug_message(const char *module_name, const char *func, const char *file,
                          const char *fmt, ...);

/* verbosity levels. */
extern int get_verbosity_level(void);
extern int set_verbosity_level(int verbosity_level_to_set);

/* dynamic allocation wrappers. */
extern void *xmalloc(size_t size);
extern void *xcalloc(size_t size);
extern void xfree(void *p);
extern void *xrealloc(void *p, size_t size);

/* signal/interrupt handlers. */
extern int check_for_interrupts(void);
extern void suspend_for_interrupts(void);
extern void block_interrupts(void);
extern void add_interrupt_handler(int sigtype, void (*sighandler) (int));
extern void remove_interrupt(int sig);
extern int peek_interrupt_type(void);
extern int user_interrupt(void);

/* alarm handlers. */
extern int had_alarm(void);
extern void set_alarm(uint32_t alarm_time);
extern void remove_alarm(void);

/* string routines -- XXX FIXME: we eventually want everything in
 * stringbuffer */

extern char *splice_string(const char *s1, const char *s2);
extern char *splice_many_strings(int num, char *s, ...);
extern int string_matches(const char *s1, const char *s2);
extern int hex_string_to_value(const char *string, unsigned char *dst);
extern int is_string(const char *string, int len);
extern char *xstrdup(const char *string);

/* random number gen. */
extern uint16_t get_random_uint16(void);
extern uint32_t get_random_uint32(void);

/* misc. */
extern struct timeval timeval_diff(struct timeval begin, struct timeval end);
extern const char *getprogname(void);
extern ip_addr_t *string_ip_to_ip_addr(const char *string_ip);
extern eth_addr_t *string_eth_addr_to_eth_addr(const char *eth_ip);
extern char *eth_addr_to_string(eth_addr_t eth_addr);
extern char *ip_addr_to_string(ip_addr_t ip_addr);
extern void sleep_random(uint16_t max_sleep);
extern void do_change_work_dir(const char *dir);

/* type check routines */
extern int is_seven_bit_clean(const char *data, int len);
extern int is_signed_numeric(const char *string);
extern int is_unsigned_numeric(const char *string);

/* Replacement vsnprintf, snprintf that work the way we want them to. */
extern int snprintf(char *str, size_t count, const char *fmt, ...);
extern int vsnprintf(char *str, size_t count, const char *fmt, va_list arg);

/* Linked List routines. */
extern list_t *list_create(void);
extern void list_add(list_t *list, void *data);
extern void list_add_to_end(list_t *list, void *data);
extern int list_remove_by_datum(list_t *list, void *data);
extern void list_destroy(list_t *list, void (*purge_func) (void *d));
extern void list_join(list_t *first_list, list_t *second_list);
extern list_t *list_sort(list_t *list, int (*compare) (void *, void *));
extern void *list_get_by_index(list_t *list, int index);
extern void *list_first(list_t *list);
extern void *list_second(list_t *list);
extern void list_rewind(list_t *list);
extern void *list_next(list_t *list);
extern int list_get_len(list_t *list);
extern list_t *list_copy(list_t *list, size_t data_size);

/* stringbuffer. */
extern stringbuffer_t *stringbuffer_create(void);
extern void stringbuffer_destroy(stringbuffer_t *sb);
extern void stringbuffer_clear(stringbuffer_t *sb);
extern void stringbuffer_append_c(stringbuffer_t *sb, char c);
extern void stringbuffer_append(stringbuffer_t *sb, const char *s);
extern stringbuffer_t *stringbuffer_trim_whitespace(stringbuffer_t *sb);
extern char *stringbuffer_get_last_occurance(stringbuffer_t *sb, char c);
extern void stringbuffer_trim_newline(stringbuffer_t *sb);
extern const char *stringbuffer_getstring(stringbuffer_t *sb);
extern void stringbuffer_set(stringbuffer_t *dest, const char *s);
extern void stringbuffer_copy(stringbuffer_t *dest, stringbuffer_t *src);
extern void stringbuffer_replace_c(stringbuffer_t *sb, char c, char replace);
extern void stringbuffer_replace(stringbuffer_t *sb, const char *string, const char *replace);
extern void stringbuffer_align(stringbuffer_t *sb, int begin, int end);
extern void stringbuffer_avprintf_align(stringbuffer_t *sb, int start, int end, const char *fmt, va_list ap);
extern void stringbuffer_aprintf(stringbuffer_t *sb, const char *fmt, ...);
extern void stringbuffer_aprintf_align(stringbuffer_t *sb, int start, int end, const char *fmt, ...);
extern void stringbuffer_avprintf(stringbuffer_t *sb, const char *fmt, va_list ap);
extern int stringbuffer_marknewlines(stringbuffer_t *sb);
extern const char *stringbuffer_getnextline(stringbuffer_t *sb, const char *cptr);
extern int stringbuffer_getlen(stringbuffer_t *sb);

/* RTT mechanism. */
extern rtt_t *rtt_create(time_t max_timeout);
extern struct timeval rtt_get_timeout(rtt_t *rtt);
extern void rtt_timeout(rtt_t *rtt);
extern int rtt_can_retry(rtt_t *rtt);
extern void rtt_destroy(rtt_t *rtt);

/* interactive mode switch. */
extern void set_interactive(uint8_t interactive_arg);

/* timer object. */
extern timer_keeper_t *create_timer(void);
extern void destroy_timer(timer_keeper_t *timer);
extern int timer_set_next(timer_keeper_t *timer);
extern void timer_add_trigger(timer_keeper_t *timer, uint32_t time, uint32_t id);
extern int timer_purge(timer_keeper_t);
extern uint32_t timer_get_current_id(timer_keeper_t *timer);
extern void reinitialize_timer(timer_keeper_t *timer);
extern uint32_t timer_peek_next_timer(timer_keeper_t *timer);
extern timer_keeper_t *timer_copy(timer_keeper_t *timer);

/* var file. */
extern varfile_t *create_varfile(const char *filename, uint8_t mode);
extern void destroy_varfile(varfile_t *varfile);
extern const char *varfile_get_name(varfile_t *varfile);
extern const char *varfile_get_val(varfile_t *varfile);
extern int varfile_get_lineno(varfile_t *varfile);
extern const char *varfile_get_filename(varfile_t *varfile);
extern int varfile_get_next_var(varfile_t *varfile);

/* file routines. */
extern FILE *file_open_or_create_safe(const char *filename, char *mode);
extern FILE *file_create_and_truncate_safe(const char *filename, char *mode);
extern int file_delete(char *fname);
extern void file_move(char *fname, char *dest);
extern int file_exists(const char *fname);
extern void file_make_public_read(char *fname);
extern int file_create_pid(char *name);
extern int file_delete_pid(char *name);
extern int file_get_pid(char *name, pid_t * pid);
extern int file_permissions_are(const char *fname, mode_t mode);

/* interrupt handling. */
extern void add_interrupt_handler(int sigtype, void (*sighandler) (int));
extern void block_interrupts(void);
extern int check_for_interrupts(void);
extern void suspend_for_interrupts(void);
extern void remove_interrupt(int sig);
extern RETSIGTYPE handle_hup(int i);
extern RETSIGTYPE handle_shutdown(int i);
extern int got_interrupt_type(void);

/* configuration grammar parser */
extern conf_t *conf_create(const command_t **commands, const char *filename);
extern void conf_destroy(conf_t *conf);
extern int conf_compile_directives(conf_t *conf);
extern list_t *conf_get_directives(conf_t *conf);
extern int conf_get_line_no(conf_t *conf);

/* daemon routines. */

extern void go_background(char *dir);
extern void setup_interrupt_handlers(void);

/* constants. */

/* modes for varfiles. */
#define VARFILE_VARNAMES_MODE 0 /* just names. */
#define VARFILE_VARVAL_MODE   1 /* names and values. */

/* return values for get_next_var */
#define VARFILE_PARSE_ERROR -1 /* parse error. */
#define VARFILE_EOF          0 /* end of file. */
#define VARFILE_SUCCESS      1 /* success */

/* stringbuffer chunk allocation size. */
#define STRINGBUFFER_CHUNKSIZE 16

/* Line length for messages before breaking into a new line. */
#define MESSAGE_LINE_LENGTH 70

/* timeout as per rfc2131 */
#define MILLISECOND_TIMEOUT      4000
#define MILLISECOND_RAND_TIMEOUT 1000
#define RECOMMENDED_MAX_SECS_WAIT 64

/* constant time values. */

#define INFINITE_TIME 0xFFFFFFFF

/* macros. */

/* NELMS straight out of "The Practice of Programming" Pike and Kernighan. */
#define NELMS(x) (sizeof(x)/sizeof(x[0]))

/* log message macros. */
#define INFO_MESSAGE(...)   { info_message(__VA_ARGS__);  }
#define ERROR_MESSAGE(...)  { error_message(__func__, __VA_ARGS__); }
#define WARN_MESSAGE(...)   { warn_message(__VA_ARGS__);  }
#define FATAL_MESSAGE(...)  { fatal_message(__func__, __VA_ARGS__); }
#define DEBUG_MESSAGE(...)  { debug_message(MODULE_NAME, __func__, __FILE__, __VA_ARGS__); }

/* time macros. */
#define SECS_TO_MSECS(x)      (x * 1000)
#define MSECS_TO_SECS(x)      (x / 1000)
#define MSECS_TO_SECS_REM(x)  (x % 1000)

/* Verbosity levels. */
enum verbosity { QUIET_VERBOSITY_LEVEL = 0, ERROR_VERBOSITY_LEVEL, NORMAL_VERBOSITY_LEVEL,
    WARNING_VERBOSITY_LEVEL, DEBUG_VERBOSITY_LEVEL, MAX_VERBOSITY_LEVEL
};

/* Syslog options. */
#define LOG_OPT LOG_PID|LOG_NDELAY /* Options  */
#define LOG_FACILITY LOG_DAEMON /* Facility */
#define ERROR_LEVEL LOG_ERR /* Error level */
#define INFO_LEVEL LOG_INFO /* Normal level */

/* interrupt types. */

enum interrupt_types { INTERRUPT_NONE, INTERRUPT_ALARM, INTERRUPT_HUP, INTERRUPT_TERM };

#endif                          /* DHCP_LIBUTIL_H */