mirror of https://github.com/pygos/init.git
77 lines
2.0 KiB
C
77 lines
2.0 KiB
C
/* SPDX-License-Identifier: ISC */
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#ifndef SERVICECMD_H
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#define SERVICECMD_H
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#include <stdlib.h>
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#include <string.h>
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#include <stdio.h>
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#include <ctype.h>
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#include "util.h"
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/*
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Describes a command that can be launched by passing its name as
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second command line argument to the main() function (i.e. immediately
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after the actual program name).
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Short and long descriptions can be provided to print out help text.
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The main() function calls into a callback in this structure to execute
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the command.
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*/
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typedef struct command_t {
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struct command_t *next;
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const char *cmd; /* command name */
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const char *usage; /* list of possible arguments */
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const char *s_desc; /* short description used by help */
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const char *l_desc; /* long description used by help */
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/*
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Semantics are the same as for main(). Called from main()
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function with first argument (i.e. top level program name)
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removed.
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*/
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int (*run_cmd)(int argc, char **argv);
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} command_t;
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/* Global list of available commands */
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extern command_t *commands;
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/*
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Implemented in servicecmd.c. Prints program usage message and
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terminates with the given exit status.
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*/
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void usage(int status) NORETURN;
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/*
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Write a message to stderr that advises the user how to consult the
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help text for a specific command.
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*/
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void tell_read_help(const char *cmd);
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/*
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Check if the argument count is within specified bounds (minc and maxc
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inclusive). If it is, return 0.
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If it isn't, complain about a wrong number of arguments for a
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command (cmd), tell the user to consult the help text and return -1.
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*/
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int check_arguments(const char *cmd, int argc, int minc, int maxc);
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/*
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To implement a new command, add a global, static instance of a
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command_t (or derived) structure to a C file and pass it to this
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macro to have it automatically registered on program startup.
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*/
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#define REGISTER_COMMAND(cmd) \
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static void __attribute__((constructor)) register_##cmd(void) \
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{ \
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command_t *c = (command_t *)&cmd; \
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\
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c->next = commands; \
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commands = c; \
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}
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#endif /* SERVICECMD_H */
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