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1.1 root 1: /* $Source: /src386/usr/bin/pax/names.c,v $
2: *
3: * $Revision: 1.1 $
4: *
5: * names.c - Look up user and/or group names.
6: *
7: * DESCRIPTION
8: *
9: * These functions support UID and GID name lookup. The results are
10: * cached to improve performance.
11: *
12: * AUTHOR
13: *
14: * Mark H. Colburn, NAPS International ([email protected])
15: *
16: * Sponsored by The USENIX Association for public distribution.
17: *
18: * Copyright (c) 1989 Mark H. Colburn.
19: * All rights reserved.
20: *
21: * Redistribution and use in source and binary forms are permitted
22: * provided that the above copyright notice is duplicated in all such
23: * forms and that any documentation, advertising materials, and other
24: * materials related to such distribution and use acknowledge that the
25: * software was developed * by Mark H. Colburn and sponsored by The
26: * USENIX Association.
27: *
28: * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
29: * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
30: * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
31: *
32: * $Log: names.c,v $
33: * Revision 1.1 92/08/28 08:02:21 bin
34: * Initial revision
35: *
36: * Revision 1.1 89/02/14 16:48:03 jep
37: * Initial revision
38: *
39: * Revision 1.1 88/12/23 18:02:19 mark
40: * Initial revision
41: *
42: */
43:
44: #ifndef lint
45: static char *ident = "$Id: names.c,v 1.1 92/08/28 08:02:21 bin Exp Locker: bin $";
46: static char *copyright = "Copyright (c) 1989 Mark H. Colburn.\nAll rights reserved.\n";
47: #endif /* ! lint */
48:
49:
50: /* Headers */
51:
52: #include "pax.h"
53:
54:
55: /* Defines */
56:
57: #define myuid ( my_uid < 0? (my_uid = getuid()): my_uid )
58: #define mygid ( my_gid < 0? (my_gid = getgid()): my_gid )
59:
60:
61: /* Internal Identifiers */
62:
63: static int saveuid = -993;
64: static char saveuname[TUNMLEN];
65: static int my_uid = -993;
66:
67: static int savegid = -993;
68: static char savegname[TGNMLEN];
69: static int my_gid = -993;
70:
71:
72: /* finduname - find a user or group name from a uid or gid
73: *
74: * DESCRIPTION
75: *
76: * Look up a user name from a uid/gid, maintaining a cache.
77: *
78: * PARAMETERS
79: *
80: * char uname[] - name (to be returned to user)
81: * int uuid - id of name to find
82: *
83: *
84: * RETURNS
85: *
86: * Returns a name which is associated with the user id given. If there
87: * is not name which corresponds to the user-id given, then a pointer
88: * to a string of zero length is returned.
89: *
90: * FIXME
91: *
92: * 1. for now it's a one-entry cache.
93: * 2. The "-993" is to reduce the chance of a hit on the first lookup.
94: */
95:
96: #if __STDC__
97:
98: char *finduname(int uuid)
99:
100: #else
101:
102: char *finduname(uuid)
103: int uuid;
104:
105: #endif
106: {
107: struct passwd *pw;
108:
109: if (uuid != saveuid) {
110: saveuid = uuid;
111: saveuname[0] = '\0';
112: pw = getpwuid(uuid);
113: if (pw) {
114: strncpy(saveuname, pw->pw_name, TUNMLEN);
115: }
116: }
117: return(saveuname);
118: }
119:
120:
121: /* finduid - get the uid for a given user name
122: *
123: * DESCRIPTION
124: *
125: * This does just the opposit of finduname. Given a user name it
126: * finds the corresponding UID for that name.
127: *
128: * PARAMETERS
129: *
130: * char uname[] - username to find a UID for
131: *
132: * RETURNS
133: *
134: * The UID which corresponds to the uname given, if any. If no UID
135: * could be found, then the UID which corrsponds the user running the
136: * program is returned.
137: *
138: */
139:
140: #if __STDC__
141:
142: int finduid(char *uname)
143:
144: #else
145:
146: int finduid(uname)
147: char *uname;
148:
149: #endif
150: {
151: struct passwd *pw;
152: extern struct passwd *getpwnam();
153:
154: if (uname[0] != saveuname[0]/* Quick test w/o proc call */
155: ||0 != strncmp(uname, saveuname, TUNMLEN)) {
156: strncpy(saveuname, uname, TUNMLEN);
157: pw = getpwnam(uname);
158: if (pw) {
159: saveuid = pw->pw_uid;
160: } else {
161: saveuid = myuid;
162: }
163: }
164: return (saveuid);
165: }
166:
167:
168: /* findgname - look up a group name from a gid
169: *
170: * DESCRIPTION
171: *
172: * Look up a group name from a gid, maintaining a cache.
173: *
174: *
175: * PARAMETERS
176: *
177: * int ggid - goupid of group to find
178: *
179: * RETURNS
180: *
181: * A string which is associated with the group ID given. If no name
182: * can be found, a string of zero length is returned.
183: */
184:
185: #if __STDC__
186:
187: char *findgname(int ggid)
188:
189: #else
190:
191: char *findgname(ggid)
192: int ggid;
193:
194: #endif
195: {
196: struct group *gr;
197:
198: if (ggid != savegid) {
199: savegid = ggid;
200: savegname[0] = '\0';
201: setgrent();
202: gr = getgrgid(ggid);
203: if (gr) {
204: strncpy(savegname, gr->gr_name, TGNMLEN);
205: }
206: }
207: return(savegname);
208: }
209:
210:
211:
212: /* findgid - get the gid for a given group name
213: *
214: * DESCRIPTION
215: *
216: * This does just the opposit of finduname. Given a group name it
217: * finds the corresponding GID for that name.
218: *
219: * PARAMETERS
220: *
221: * char uname[] - groupname to find a GID for
222: *
223: * RETURNS
224: *
225: * The GID which corresponds to the uname given, if any. If no GID
226: * could be found, then the GID which corrsponds the group running the
227: * program is returned.
228: *
229: */
230:
231: #if __STDC__
232:
233: int findgid(char *gname)
234:
235: #else
236:
237: int findgid(gname)
238: char *gname;
239:
240: #endif
241: {
242: struct group *gr;
243:
244: /* Quick test w/o proc call */
245: if (gname[0] != savegname[0] || strncmp(gname, savegname, TUNMLEN) != 0) {
246: strncpy(savegname, gname, TUNMLEN);
247: gr = getgrnam(gname);
248: if (gr) {
249: savegid = gr->gr_gid;
250: } else {
251: savegid = mygid;
252: }
253: }
254: return (savegid);
255: }
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