utils-std

getconf.c (7041B)

// utils-std: Collection of commonly available Unix tools
// SPDX-FileCopyrightText: 2017 Haelwenn (lanodan) Monnier <contact+utils@hacktivis.me>
// SPDX-License-Identifier: MPL-2.0
#define _POSIX_C_SOURCE 202405L
#define _XOPEN_SOURCE 800
#include "../lib/getopt_nolong.h"
#include <assert.h>
#include <errno.h>
#include <limits.h>
#include <stdbool.h>
#include <stdio.h>  // fputs
#include <stdlib.h> // exit
#include <string.h> // strerror
#include <unistd.h> // getopt, pathconf
// need to be after system headers
#include "./getconf_vars.h"
const char *argv0 = "getconf";
static int
print_system_var(const char *var)
{
	for(size_t i = 0; i < (sizeof(confstr_vars) / sizeof(*confstr_vars)); i++)
	{
		if(strcmp(confstr_vars[i].name, var) != 0) continue;
		errno = 0;
		size_t buflen = confstr(confstr_vars[i].value, (char *)NULL, 0);
		if(buflen == 0)
		{
			if(errno != 0)
			{
				fprintf(stderr,
				        "getconf: error: confstr(%d /* \"%s\" */, NULL, 0): %s\n",
				        confstr_vars[i].value,
				        var,
				        strerror(errno));
				return 1;
			}
			printf("undefined\n");
			return 0;
		}
		errno = 0;
		char *buf = malloc(buflen);
		if(!buf)
		{
			fprintf(stderr,
			        "getconf: error: Failed to allocate %zd bytes buffer for confstr: %s\n",
			        buflen,
			        strerror(errno));
			return 1;
		}
		errno = 0;
		size_t ret = confstr(confstr_vars[i].value, buf, buflen);
		if(ret == 0)
		{
			if(errno != 0)
			{
				fprintf(stderr,
				        "getconf: error: confstr(%d /* \"%s\" */, buf, %zd): %s\n",
				        confstr_vars[i].value,
				        var,
				        buflen,
				        strerror(errno));
				free(buf);
				return 1;
			}
			printf("undefined\n");
			free(buf);
			return 0;
		}
		fwrite(buf, (ret - 1), 1, stdout);
		free(buf);
		return 0;
	}
	for(size_t i = 0; i < (sizeof(sysconf_vars) / sizeof(*sysconf_vars)); i++)
	{
		if(strcmp(sysconf_vars[i].name, var) != 0) continue;
		errno = 0;
		long ret = sysconf((int)(sysconf_vars[i].value));
		if(ret == -1 && errno != 0)
		{
			fprintf(stderr,
			        "getconf: error: sysconf(%d /* \"%s\" */): %s\n",
			        sysconf_vars[i].value,
			        var,
			        strerror(errno));
			return 1;
		}
		if(ret == -1) ret = sysconf_vars[i].limit_h;
		if(ret == -1)
		{
			printf("undefined\n");
			return 0;
		}
		printf("%ld\n", ret);
		return 0;
	}
	for(size_t i = 0; i < (sizeof(limits_vars) / sizeof(*limits_vars)); i++)
	{
		if(strcmp(limits_vars[i].name, var) != 0) continue;
		long ret = limits_vars[i].limit_h;
		if(ret == -1)
		{
			printf("undefined\n");
			return 0;
		}
		printf("%ld\n", ret);
		return 0;
	}
	fprintf(stderr, "getconf: error: unknown system_var \"%s\"\n", var);
	return 1;
}
int
main(int argc, char *argv[])
{
	bool o_all = false;
	int c = -1;
	while((c = getopt_nolong(argc, argv, ":av:")) != -1)
	{
		switch(c)
		{
		case 'a':
			o_all = true;
			break;
		case 'v':
			fputs("getconf: -v option is unsupported\n", stderr);
			return 1;
		}
	}
	argc -= optind;
	argv += optind;
	if(!o_all && argc == 1)
	{
		return print_system_var(argv[0]);
	}
	else if(!o_all && argc == 2)
	{
		for(size_t i = 0; i < (sizeof(pathconf_vars) / sizeof(*pathconf_vars)); i++)
		{
			if(strcmp(pathconf_vars[i].name, argv[0]) != 0) continue;
			errno = 0;
			long ret = pathconf(argv[1], (int)(pathconf_vars[i].value));
			if(ret == -1 && errno != 0)
			{
				fprintf(stderr,
				        "getconf: error: pathconf(\"%s\", %d /* \"%s\" */): %s\n",
				        argv[1],
				        pathconf_vars[i].value,
				        argv[0],
				        strerror(errno));
				return 1;
			}
			if(ret == -1) ret = pathconf_vars[i].limit_h;
			printf("%ld\n", ret);
			return 0;
		}
		fprintf(stderr, "getconf: error: unknown path_var \"%s\"\n", argv[0]);
		return 1;
	}
	else if(o_all && (argc == 0 || argc == 1))
	{
		int err = 0;
		char *buf = NULL;
		size_t buflen = 0;
		for(size_t i = 0; i < (sizeof(confstr_vars) / sizeof(*confstr_vars)); i++)
		{
			errno = 0;
			size_t buflen_ret = confstr(confstr_vars[i].value, (char *)NULL, 0);
			if(buflen_ret == 0)
			{
				if(errno != 0)
				{
					fprintf(stderr,
					        "getconf: error: confstr(%d /* \"%s\" */, NULL, 0): %s\n",
					        confstr_vars[i].value,
					        confstr_vars[i].name,
					        strerror(errno));
					err = 1;
					continue;
				}
				printf("%s: undefined\n", confstr_vars[i].name);
				continue;
			}
			if(buflen_ret > buflen)
			{
				errno = 0;
				char *buf_ret = realloc(buf, buflen_ret);
				if(!buf_ret)
				{
					fprintf(stderr,
					        "getconf: error: Failed to allocate %zd bytes buffer for confstr: %s\n",
					        buflen,
					        strerror(errno));
					err = 1;
					continue;
				}
				buflen = buflen_ret;
				buf = buf_ret;
			}
			errno = 0;
			size_t ret = confstr(confstr_vars[i].value, buf, buflen);
			if(ret == 0)
			{
				if(errno != 0)
				{
					fprintf(stderr,
					        "getconf: error: confstr(%d /* \"%s\" */, buf, %zd): %s\n",
					        confstr_vars[i].value,
					        confstr_vars[i].name,
					        buflen,
					        strerror(errno));
					err = 1;
					continue;
				}
				printf("%s: undefined\n", confstr_vars[i].name);
				continue;
			}
			printf("%s: ", confstr_vars[i].name);
			fwrite(buf, (ret - 1), 1, stdout);
			printf("\n");
		}
		free(buf);
		for(size_t i = 0; i < (sizeof(sysconf_vars) / sizeof(*sysconf_vars)); i++)
		{
			errno = 0;
			long ret = sysconf((int)(sysconf_vars[i].value));
			if(ret == -1 && errno != 0)
			{
				fprintf(stderr,
				        "getconf: error: sysconf(%d /* \"%s\" */): %s\n",
				        sysconf_vars[i].value,
				        sysconf_vars[i].name,
				        strerror(errno));
				err = 1;
				continue;
			}
			if(ret == -1) ret = sysconf_vars[i].limit_h;
			if(ret == -1)
			{
				printf("%s: undefined\n", sysconf_vars[i].name);
				continue;
			}
			printf("%s: %ld\n", sysconf_vars[i].name, ret);
		}
		for(size_t i = 0; i < (sizeof(limits_vars) / sizeof(*limits_vars)); i++)
		{
			long ret = limits_vars[i].limit_h;
			if(ret == -1)
			{
				printf("%s: undefined\n", limits_vars[i].name);
				continue;
			}
			printf("%s: %ld\n", limits_vars[i].name, ret);
		}
		const char *path = argc == 1 ? argv[0] : ".";
		for(size_t i = 0; i < (sizeof(pathconf_vars) / sizeof(*pathconf_vars)); i++)
		{
			errno = 0;
			long ret = pathconf(path, (int)(pathconf_vars[i].value));
			if(ret == -1 && errno != 0)
			{
				fprintf(stderr,
				        "getconf: error: pathconf(\"%s\", %d /* \"%s\" */): %s\n",
				        path,
				        pathconf_vars[i].value,
				        pathconf_vars[i].name,
				        strerror(errno));
				err = 1;
				continue;
			}
			if(ret == -1) ret = pathconf_vars[i].limit_h;
			printf("%s: %ld\n", pathconf_vars[i].name, ret);
		}
		return err;
	}
	else
	{
		fprintf(stderr, "getconf: error: wrong number of arguments\n");
		fprintf(stderr, "\
Usage: getconf <system_var>\n\
       getconf <path_var> <path>\n\
       getconf -a [path]\n\
");
		return 1;
	}
}