xref: /freebsd/contrib/tcpdump/missing/getservent.c (revision 4543ef516683042d46f3bd3bb8a4f3f746e00499)
1 /*
2  * Copyright (c) 1983, 1993	The Regents of the University of California.
3  * Copyright (c) 1993 Digital Equipment Corporation.
4  * Copyright (c) 2012 G. Vanem <gvanem@yahoo.no>.
5  * Copyright (c) 2017 Ali Abdulkadir <autostart.ini@gmail.com>.
6  * All rights reserved.
7  *
8  * Redistribution and use in source and binary forms, with or without
9  * modification, are permitted provided that the following conditions
10  * are met:
11  * 1. Redistributions of source code must retain the above copyright
12  *    notice, this list of conditions and the following disclaimer.
13  * 2. Redistributions in binary form must reproduce the above copyright
14  *    notice, this list of conditions and the following disclaimer in the
15  *    documentation and/or other materials provided with the distribution.
16  * 3. All advertising materials mentioning features or use of this software
17  *    must display the following acknowledgement:
18  *	This product includes software developed by the University of
19  *	California, Berkeley and its contributors.
20  * 4. Neither the name of the University nor the names of its contributors
21  *    may be used to endorse or promote products derived from this software
22  *    without specific prior written permission.
23  *
24  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
25  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
28  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34  * SUCH DAMAGE.
35  */
36 
37 #ifdef HAVE_CONFIG_H
38 #include <config.h>
39 #endif
40 
41 #include <netdissect-stdinc.h>
42 #include <getservent.h>
43 
44 static FILE *servf = NULL;
45 static char line[BUFSIZ+1];
46 static struct servent serv;
47 static char *serv_aliases[MAXALIASES];
48 int _serv_stayopen;
49 const char *etc_path(const char *file);
50 
51 /*
52 * Check if <file> exists in the current directory and, if so, return it.
53 * Else return either "%SYSTEMROOT%\System32\drivers\etc\<file>"
54 * or $PREFIX/etc/<file>.
55 * "<file>" is aka __PATH_SERVICES (aka "services" on Windows and
56 * "/etc/services" on other platforms that would need this).
57 */
58 const char *etc_path(const char *file)
59 {
60     const char *env = getenv(__PATH_SYSROOT);
61     static char path[_MAX_PATH];
62 
63     /* see if "<file>" exists locally or whether __PATH_SYSROOT is valid */
64     if (fopen(file, "r") || !env)
65         return (file);
66     else
67 #ifdef _WIN32
68     snprintf(path, sizeof(path), "%s%s%s", env, __PATH_ETC_INET, file);
69 #else
70     snprintf(path, sizeof(path), "%s%s", env, file);
71 #endif
72     return (path);
73 }
74 
75 void
76 setservent(int f)
77 {
78     if (servf == NULL)
79         servf = fopen(etc_path(__PATH_SERVICES), "r");
80     else
81         rewind(servf);
82     _serv_stayopen |= f;
83 }
84 
85 void
86 endservent(void)
87 {
88     if (servf) {
89         fclose(servf);
90         servf = NULL;
91     }
92     _serv_stayopen = 0;
93 }
94 
95 struct servent *
96 getservent(void)
97 {
98     char *p;
99     char *cp, **q;
100 
101     if (servf == NULL && (servf = fopen(etc_path(__PATH_SERVICES), "r")) == NULL)
102         return (NULL);
103 
104 again:
105     if ((p = fgets(line, BUFSIZ, servf)) == NULL)
106         return (NULL);
107     if (*p == '#')
108         goto again;
109     cp = strpbrk(p, "#\n");
110     if (cp == NULL)
111         goto again;
112     *cp = '\0';
113     serv.s_name = p;
114     p = strpbrk(p, " \t");
115     if (p == NULL)
116         goto again;
117     *p++ = '\0';
118     while (*p == ' ' || *p == '\t')
119         p++;
120     cp = strpbrk(p, ",/");
121     if (cp == NULL)
122         goto again;
123     *cp++ = '\0';
124     serv.s_port = htons((u_short)atoi(p));
125     serv.s_proto = cp;
126     q = serv.s_aliases = serv_aliases;
127     cp = strpbrk(cp, " \t");
128     if (cp != NULL)
129         *cp++ = '\0';
130     while (cp && *cp) {
131         if (*cp == ' ' || *cp == '\t') {
132             cp++;
133             continue;
134         }
135         if (q < &serv_aliases[MAXALIASES - 1])
136             *q++ = cp;
137         cp = strpbrk(cp, " \t");
138         if (cp != NULL)
139             *cp++ = '\0';
140     }
141     *q = NULL;
142     return (&serv);
143 }
144