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https://github.com/jart/cosmopolitan.git
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implement getservbyname and getservbyport
getservbyname and getservbyport have implementation similar to that of gethostbyname and gethostbyaddr. However, there is no struct ServicesTxt like struct HostsTxt. For every call of getservbyname/getservbyport the lookup of /etc/services is done by opening the file and parsing each line one-by-one. This is slow, but the implementation is simple, and the file parsing is similar to ParseHostsTxt.
This commit is contained in:
ahgamut
parent
5e8d035302
commit
8c9750fb30
5 changed files with 269 additions and 3 deletions
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@ -19,7 +19,7 @@ struct hostent {
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struct servent {
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char *s_name; /* official service name */
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char **s_aliases; /* alias list */
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int s_port; /* port number */
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int s_port; /* port number (in network byte order) */
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char *s_proto; /* protocol to use */
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};
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@ -26,7 +26,37 @@
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│ │
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╚─────────────────────────────────────────────────────────────────────────────*/
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#include "libc/dns/ent.h"
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#include "libc/dns/servicestxt.h"
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#include "libc/mem/mem.h"
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struct servent *getservbyname(const char *name, const char *proto) {
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return NULL;
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static struct servent *ptr0, se0;
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char *localproto = proto;
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int p;
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if (!ptr0) {
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se0.s_name = NULL;
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se0.s_aliases = (char **)malloc(sizeof(char *) * 1);
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if (!se0.s_aliases) return NULL;
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se0.s_aliases[0] = NULL;
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se0.s_port = 0;
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se0.s_proto = NULL;
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ptr0 = &se0;
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}
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p = LookupServicesByName(name, &localproto);
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if (p == -1) return NULL;
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ptr0->s_port = p;
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if (ptr0->s_name) free(ptr0->s_name);
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ptr0->s_name = strdup(name);
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if (ptr0->s_proto) free(ptr0->s_proto);
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ptr0->s_proto = strdup(localproto);
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// localproto got alloc'd during the lookup
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if (!proto && localproto != proto) free(localproto);
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return ptr0;
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}
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@ -26,7 +26,36 @@
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│ │
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╚─────────────────────────────────────────────────────────────────────────────*/
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#include "libc/dns/ent.h"
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#include "libc/dns/servicestxt.h"
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struct servent *getservbyport(int port, const char *proto) {
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return NULL;
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static struct servent *ptr1, se1;
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char name[DNS_NAME_MAX];
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char *localproto = proto;
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if (!ptr1) {
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se1.s_name = NULL;
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se1.s_aliases = (char **)malloc(sizeof(char *) * 1);
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if (!se1.s_aliases) return NULL;
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se1.s_aliases[0] = NULL;
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se1.s_port = 0;
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se1.s_proto = NULL;
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ptr1 = &se1;
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}
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if (LookupServicesByPort(port, &localproto, name, sizeof(name)) == -1)
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return NULL;
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ptr1->s_port = port;
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if (ptr1->s_name) free(ptr1->s_name);
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ptr1->s_name = strdup(name);
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if (ptr1->s_proto) free(ptr1->s_proto);
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ptr1->s_proto = strdup(localproto);
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// localproto got alloc'd during the lookup
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if (!proto && localproto != proto) free(localproto);
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return ptr1;
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}
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190
libc/dns/servicestxt.c
Normal file
190
libc/dns/servicestxt.c
Normal file
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@ -0,0 +1,190 @@
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/*-*- 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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╚─────────────────────────────────────────────────────────────────────────────*/
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#include "libc/dns/servicestxt.h"
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#include "libc/bits/safemacros.internal.h"
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#include "libc/dce.h"
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#include "libc/errno.h"
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#include "libc/fmt/conv.h"
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#include "libc/fmt/fmt.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/nt/systeminfo.h"
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#include "libc/runtime/runtime.h"
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#include "libc/str/str.h"
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static textwindows noinline char *GetNtServicesTxtPath(char *pathbuf,
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uint32_t size) {
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const char *const kWinHostsPath = "\\drivers\\etc\\services";
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uint32_t len = GetSystemDirectoryA(&pathbuf[0], size);
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if (len && len + strlen(kWinHostsPath) + 1 < size) {
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if (pathbuf[len] == '\\') pathbuf[len--] = '\0';
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memcpy(&pathbuf[len], kWinHostsPath, strlen(kWinHostsPath) + 1);
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return &pathbuf[0];
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} else {
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return NULL;
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}
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}
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/**
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* Opens and searches /etc/services to find name for a given port.
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*
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* format of /etc/services is like this:
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*
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* # comment
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* # NAME PORT/PROTOCOL ALIASES
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*
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* ftp 21/tcp
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* fsp 21/udp fspd
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* ssh 22/tcp
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*
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* @param servport is the port number (in network byte order)
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* @param servproto is a pointer to a string (*servproto can be NULL)
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* @param buf is a buffer to store the resulting name
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* @param bufsize is the size of buf
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* @returns 0 on success, -1 on error
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*
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* @note aliases are not read from the file.
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*/
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int LookupServicesByPort(const int servport, char **servproto, char *buf,
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size_t bufsize) {
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FILE *f;
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char *line;
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char pathbuf[512];
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const char *path;
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size_t linesize;
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int count, found;
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char *name, *port, *proto, *comment, *tok;
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path = "/etc/services";
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if (IsWindows()) {
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path = firstnonnull(GetNtServicesTxtPath(pathbuf, ARRAYLEN(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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count = 0;
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found = 0;
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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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port = strtok_r(NULL, "/ \t\r\n\v", &tok);
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if (name && port && servport == htons(atoi(port))) {
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if (!(proto = strtok_r(NULL, " \t\r\n\v", &tok)))
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continue;
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else if (!servproto[0]) {
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servproto[0] = strdup(proto);
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strncpy(buf, name, bufsize);
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found = 1;
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} else if (strcmp(proto, servproto[0]) == 0) {
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strncpy(buf, name, bufsize);
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found = 1;
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}
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}
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count++;
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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 0;
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}
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/**
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* Opens and searches /etc/services to find port for a given name.
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*
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* @param servname is a NULL-terminated string
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* @param servproto is a pointer to a string (*servproto can be NULL)
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* @returns -1 on error, or
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* positive port number (in network byte order)
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*
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* @note aliases are not read from the file.
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* @see LookupServicesByPort
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*/
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int LookupServicesByName(const char *servname, char **servproto) {
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FILE *f;
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char *line;
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char pathbuf[512];
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const char *path;
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size_t linesize;
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int count, found, result;
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char *name, *port, *proto, *comment, *tok;
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path = "/etc/services";
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if (IsWindows()) {
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path = firstnonnull(GetNtServicesTxtPath(pathbuf, ARRAYLEN(pathbuf)), path);
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}
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if (!(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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count = 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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port = strtok_r(NULL, "/ \t\r\n\v", &tok);
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if (name && port && strcmp(name, servname) == 0) {
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if (!(proto = strtok_r(NULL, " \t\r\n\v", &tok)))
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continue;
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else if (!servproto[0]) {
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servproto[0] = strdup(proto);
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result = htons(atoi(port));
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found = 1;
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} else if (strcmp(proto, servproto[0]) == 0) {
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result = htons(atoi(port));
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found = 1;
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}
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}
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count++;
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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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17
libc/dns/servicestxt.h
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17
libc/dns/servicestxt.h
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@ -0,0 +1,17 @@
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#ifndef COSMOPOLITAN_LIBC_DNS_SERVICESTXT_H_
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#define COSMOPOLITAN_LIBC_DNS_SERVICESTXT_H_
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#include "libc/sock/sock.h"
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#include "libc/stdio/stdio.h"
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#if !(__ASSEMBLER__ + __LINKER__ + 0)
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COSMOPOLITAN_C_START_
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int LookupServicesByPort(const int, char **, char *, size_t)
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paramsnonnull((2, 3));
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int LookupServicesByName(const char *, char **) paramsnonnull((1, 2));
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/* TODO: implement like struct HostsTxt? */
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COSMOPOLITAN_C_END_
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#endif /* !(__ASSEMBLER__ + __LINKER__ + 0) */
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#endif /* COSMOPOLITAN_LIBC_DNS_SERVICESTXT_H_ */
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