xref: /freebsd/contrib/tcpdump/missing/getservent.c (revision 87b759f0fa1f7554d50ce640c40138512bbded44)
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 #include <config.h>
38 
39 #include <netdissect-stdinc.h>
40 #include <getservent.h>
41 
42 static FILE *servf = NULL;
43 static char line[BUFSIZ+1];
44 static struct servent serv;
45 static char *serv_aliases[MAXALIASES];
46 int _serv_stayopen;
47 const char *etc_path(const char *file);
48 
49 /*
50 * Check if <file> exists in the current directory and, if so, return it.
51 * Else return either "%SYSTEMROOT%\System32\drivers\etc\<file>"
52 * or $PREFIX/etc/<file>.
53 * "<file>" is aka __PATH_SERVICES (aka "services" on Windows and
54 * "/etc/services" on other platforms that would need this).
55 */
56 const char *etc_path(const char *file)
57 {
58     const char *env = getenv(__PATH_SYSROOT);
59     static char path[_MAX_PATH];
60 
61     /* see if "<file>" exists locally or whether __PATH_SYSROOT is valid */
62     if (fopen(file, "r") || !env)
63         return (file);
64     else
65 #ifdef _WIN32
66     snprintf(path, sizeof(path), "%s%s%s", env, __PATH_ETC_INET, file);
67 #else
68     snprintf(path, sizeof(path), "%s%s", env, file);
69 #endif
70     return (path);
71 }
72 
73 void
74 setservent(int f)
75 {
76     if (servf == NULL)
77         servf = fopen(etc_path(__PATH_SERVICES), "r");
78     else
79         rewind(servf);
80     _serv_stayopen |= f;
81 }
82 
83 void
84 endservent(void)
85 {
86     if (servf) {
87         fclose(servf);
88         servf = NULL;
89     }
90     _serv_stayopen = 0;
91 }
92 
93 struct servent *
94 getservent(void)
95 {
96     char *p;
97     char *cp, **q;
98 
99     if (servf == NULL && (servf = fopen(etc_path(__PATH_SERVICES), "r")) == NULL)
100         return (NULL);
101 
102 again:
103     if ((p = fgets(line, BUFSIZ, servf)) == NULL)
104         return (NULL);
105     if (*p == '#')
106         goto again;
107     cp = strpbrk(p, "#\n");
108     if (cp == NULL)
109         goto again;
110     *cp = '\0';
111     serv.s_name = p;
112     p = strpbrk(p, " \t");
113     if (p == NULL)
114         goto again;
115     *p++ = '\0';
116     while (*p == ' ' || *p == '\t')
117         p++;
118     cp = strpbrk(p, ",/");
119     if (cp == NULL)
120         goto again;
121     *cp++ = '\0';
122     serv.s_port = htons((u_short)atoi(p));
123     serv.s_proto = cp;
124     q = serv.s_aliases = serv_aliases;
125     cp = strpbrk(cp, " \t");
126     if (cp != NULL)
127         *cp++ = '\0';
128     while (cp && *cp) {
129         if (*cp == ' ' || *cp == '\t') {
130             cp++;
131             continue;
132         }
133         if (q < &serv_aliases[MAXALIASES - 1])
134             *q++ = cp;
135         cp = strpbrk(cp, " \t");
136         if (cp != NULL)
137             *cp++ = '\0';
138     }
139     *q = NULL;
140     return (&serv);
141 }
142