mirror of
https://github.com/jart/cosmopolitan.git
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101 lines
4.5 KiB
C
101 lines
4.5 KiB
C
/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
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│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi│
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╞══════════════════════════════════════════════════════════════════════════════╡
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│ This is free and unencumbered software released into the public domain. │
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│ │
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│ Anyone is free to copy, modify, publish, use, compile, sell, or │
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│ distribute this software, either in source code form or as a compiled │
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│ binary, for any purpose, commercial or non-commercial, and by any │
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│ means. │
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│ │
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│ In jurisdictions that recognize copyright laws, the author or authors │
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│ of this software dedicate any and all copyright interest in the │
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│ software to the public domain. We make this dedication for the benefit │
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│ of the public at large and to the detriment of our heirs and │
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│ successors. We intend this dedication to be an overt act of │
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│ relinquishment in perpetuity of all present and future rights to this │
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│ software under copyright law. │
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│ │
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│ THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, │
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│ EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF │
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│ MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. │
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│ IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR │
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│ OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, │
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│ ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR │
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│ OTHER DEALINGS IN THE SOFTWARE. │
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╚─────────────────────────────────────────────────────────────────────────────*/
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#include "libc/dce.h"
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#include "libc/dns/prototxt.h"
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#include "libc/errno.h"
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#include "libc/fmt/conv.h"
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#include "libc/intrin/safemacros.internal.h"
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#include "libc/macros.internal.h"
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#include "libc/mem/mem.h"
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#include "libc/str/str.h"
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/**
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* Opens and searches /etc/protocols to find number for a given name.
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*
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* @param protoname is a NULL-terminated string
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* @param buf is a buffer to store the official name of the protocol
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* @param bufsize is the size of buf
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* @param filepath is the location of protocols file
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* (if NULL, uses /etc/protocols)
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* @return -1 on error, or
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* positive protocol number
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*
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* @note aliases are read from file for comparison, but not returned.
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* @see LookupProtoByNumber
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*/
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int LookupProtoByName(const char *protoname, char *buf, size_t bufsize,
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const char *filepath) {
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FILE *f;
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char *line;
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size_t linesize;
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const char *path;
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int found, result;
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char pathbuf[256];
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char *name, *number, *alias, *comment, *tok;
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if (!(path = filepath)) {
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path =
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!IsWindows()
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? "/etc/protocols"
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: firstnonnull(GetProtocolsTxtPath(pathbuf, sizeof(pathbuf)), path);
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}
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if (bufsize == 0 || !(f = fopen(path, "r"))) {
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return -1;
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}
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line = NULL;
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linesize = 0;
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found = 0;
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result = -1;
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while (found == 0 && getline(&line, &linesize, f) != -1) {
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if ((comment = strchr(line, '#'))) *comment = '\0';
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name = strtok_r(line, " \t\r\n\v", &tok);
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number = strtok_r(NULL, "/ \t\r\n\v", &tok);
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if (name && number) {
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alias = name;
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while (alias && strcasecmp(alias, protoname)) {
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alias = strtok_r(NULL, " \t\r\n\v", &tok);
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}
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if (alias) { /* alias matched with protoname */
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if (!memccpy(buf, name, '\0', bufsize)) {
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if (bufsize) {
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*buf = 0;
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}
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break;
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}
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result = atoi(number);
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found = 1;
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}
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}
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}
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free(line);
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if (ferror(f)) {
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errno = ferror(f);
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return -1;
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}
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fclose(f);
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if (!found) return -1;
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return result;
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}
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