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1 | .\" Copyright (c) 2003 Andries Brouwer (aeb@cwi.nl) |
2 | .\" | |
3 | .\" This is free documentation; you can redistribute it and/or | |
4 | .\" modify it under the terms of the GNU General Public License as | |
5 | .\" published by the Free Software Foundation; either version 2 of | |
6 | .\" the License, or (at your option) any later version. | |
7 | .\" | |
8 | .\" The GNU General Public License's references to "object code" | |
9 | .\" and "executables" are to be interpreted as the output of any | |
10 | .\" document formatting or typesetting system, including | |
11 | .\" intermediate and printed output. | |
12 | .\" | |
13 | .\" This manual is distributed in the hope that it will be useful, | |
14 | .\" but WITHOUT ANY WARRANTY; without even the implied warranty of | |
15 | .\" MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
16 | .\" GNU General Public License for more details. | |
17 | .\" | |
18 | .\" You should have received a copy of the GNU General Public | |
19 | .\" License along with this manual; if not, write to the Free | |
20 | .\" Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111, | |
21 | .\" USA. | |
22 | .\" | |
cc4615cc | 23 | .TH GETPWENT_R 3 2007-07-26 "GNU" "Linux Programmer's Manual" |
fea681da MK |
24 | .SH NAME |
25 | getpwent_r, fgetpwent_r \- get passwd file entry reentrantly | |
26 | .SH SYNOPSIS | |
27 | .nf | |
fea681da MK |
28 | .B #include <pwd.h> |
29 | .sp | |
30 | .BI "int getpwent_r(struct passwd *" pwbuf ", char *" buf , | |
31 | .br | |
32 | .BI " size_t " buflen ", struct passwd **" pwbufp ); | |
33 | .sp | |
34 | .BI "int fgetpwent_r(FILE *" fp ", struct passwd *" pwbuf ", char *" buf , | |
35 | .br | |
36 | .BI " size_t " buflen ", struct passwd **" pwbufp ); | |
cc4615cc MK |
37 | .fi |
38 | .sp | |
39 | .in -4n | |
40 | Feature Test Macro Requirements for glibc (see | |
41 | .BR feature_test_macros (7)): | |
42 | .in | |
43 | .sp | |
44 | .BR getpwent_r (), | |
45 | _BSD_SOURCE || _SVID_SOURCE | |
46 | .br | |
47 | .BR fgetpwent_r (): | |
48 | _SVID_SOURCE | |
fea681da MK |
49 | .SH DESCRIPTION |
50 | The functions | |
63aa9df0 | 51 | .BR getpwent_r () |
fea681da | 52 | and |
63aa9df0 | 53 | .BR fgetpwent_r () |
fea681da MK |
54 | are the reentrant versions of |
55 | .BR getpwent (3) | |
56 | and | |
57 | .BR fgetpwent (3). | |
58 | The former reads the next passwd entry from the stream initialized by | |
59 | .BR setpwent (3). | |
60 | The latter reads the next passwd entry from the stream | |
61 | .I fp | |
62 | given as parameter. | |
63 | .PP | |
64 | The \fIpasswd\fP structure is defined in | |
65 | .I <pwd.h> | |
66 | as follows: | |
67 | .sp | |
68 | .RS | |
69 | .nf | |
70 | struct passwd { | |
cf0a9ace MK |
71 | char *pw_name; /* user name */ |
72 | char *pw_passwd; /* user password */ | |
73 | uid_t pw_uid; /* user ID */ | |
74 | gid_t pw_gid; /* group ID */ | |
75 | char *pw_gecos; /* real name */ | |
76 | char *pw_dir; /* home directory */ | |
77 | char *pw_shell; /* shell program */ | |
fea681da MK |
78 | }; |
79 | .fi | |
80 | .RE | |
81 | .sp | |
82 | The non-reentrant functions return a pointer to static storage, | |
83 | where this static storage contains further pointers to user | |
84 | name, password, gecos field, home directory and shell. | |
85 | The reentrant functions described here return all of that in | |
c13182ef MK |
86 | caller-provided buffers. |
87 | First of all there is the buffer | |
fea681da | 88 | .I pwbuf |
0c2ec4f1 | 89 | that can hold a \fIstruct passwd\fP. |
c13182ef | 90 | And next the buffer |
fea681da MK |
91 | .I buf |
92 | of size | |
93 | .I buflen | |
94 | that can hold additional strings. | |
0c2ec4f1 | 95 | The result of these functions, the \fIstruct passwd\fP read from the stream, |
fea681da MK |
96 | is stored in the provided buffer |
97 | .RI * pwbuf , | |
0c2ec4f1 | 98 | and a pointer to this \fIstruct passwd\fP is returned in |
fea681da MK |
99 | .RI * pwbufp . |
100 | .SH "RETURN VALUE" | |
101 | On success, these functions return 0 and | |
102 | .RI * pwbufp | |
0c2ec4f1 | 103 | is a pointer to the \fIstruct passwd\fP. |
fea681da MK |
104 | On error, these functions return an error value and |
105 | .RI * pwbufp | |
106 | is NULL. | |
107 | .SH ERRORS | |
108 | .TP | |
109 | .B ENOENT | |
110 | No more entries. | |
111 | .TP | |
112 | .B ERANGE | |
c13182ef MK |
113 | Insufficient buffer space supplied. |
114 | Try again with larger buffer. | |
2b2581ee MK |
115 | .SH "CONFORMING TO" |
116 | These functions are GNU extensions, done in a style resembling | |
117 | the POSIX version of functions like | |
118 | .BR getpwnam_r (3). | |
119 | Other systems use prototype | |
120 | .sp | |
121 | .nf | |
122 | .in +4 | |
123 | struct passwd * | |
124 | getpwent_r(struct passwd *pwd, char *buf, int buflen); | |
125 | .in | |
126 | .fi | |
127 | .sp | |
128 | or, better, | |
129 | .sp | |
130 | .nf | |
131 | .in +4 | |
132 | int | |
133 | getpwent_r(struct passwd *pwd, char *buf, int buflen, | |
134 | FILE **pw_fp); | |
135 | .in | |
136 | .fi | |
137 | .SH NOTES | |
138 | The function | |
139 | .BR getpwent_r () | |
140 | is not really reentrant since it shares the reading position | |
141 | in the stream with all other threads. | |
fea681da MK |
142 | .SH EXAMPLE |
143 | .nf | |
144 | #define _GNU_SOURCE | |
145 | #include <pwd.h> | |
146 | #include <stdio.h> | |
147 | #define BUFLEN 4096 | |
148 | ||
c13182ef MK |
149 | int |
150 | main(void) | |
cf0a9ace MK |
151 | { |
152 | struct passwd pw, *pwp; | |
153 | char buf[BUFLEN]; | |
154 | int i; | |
fea681da | 155 | |
cf0a9ace MK |
156 | setpwent(); |
157 | while (1) { | |
158 | i = getpwent_r(&pw, buf, BUFLEN, &pwp); | |
159 | if (i) | |
160 | break; | |
29059a65 MK |
161 | printf("%s (%d)\etHOME %s\etSHELL %s\en", pwp\->pw_name, |
162 | pwp\->pw_uid, pwp\->pw_dir, pwp\->pw_shell); | |
cf0a9ace MK |
163 | } |
164 | endpwent(); | |
5bc8c34c | 165 | exit(EXIT_SUCCESS); |
fea681da MK |
166 | } |
167 | .fi | |
168 | .\" perhaps add error checking - should use strerror_r | |
169 | .\" #include <errno.h> | |
170 | .\" #include <stdlib.h> | |
171 | .\" if (i) { | |
172 | .\" if (i == ENOENT) | |
173 | .\" break; | |
174 | .\" printf("getpwent_r: %s", strerror(i)); | |
4c44ffe5 | 175 | .\" exit(EXIT_SUCCESS); |
fea681da | 176 | .\" } |
fea681da MK |
177 | .SH "SEE ALSO" |
178 | .BR fgetpwent (3), | |
179 | .BR getpw (3), | |
180 | .BR getpwent (3), | |
181 | .BR getpwnam (3), | |
182 | .BR getpwuid (3), | |
183 | .BR putpwent (3), | |
cc4615cc | 184 | .BR passwd (5) |