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1 | .\" Copyright (c) 2003 Andries Brouwer (aeb@cwi.nl) |
2 | .\" | |
1dd72f9c | 3 | .\" %%%LICENSE_START(GPLv2+_DOC_FULL) |
fea681da MK |
4 | .\" This is free documentation; you can redistribute it and/or |
5 | .\" modify it under the terms of the GNU General Public License as | |
6 | .\" published by the Free Software Foundation; either version 2 of | |
7 | .\" the License, or (at your option) any later version. | |
8 | .\" | |
9 | .\" The GNU General Public License's references to "object code" | |
10 | .\" and "executables" are to be interpreted as the output of any | |
11 | .\" document formatting or typesetting system, including | |
12 | .\" intermediate and printed output. | |
13 | .\" | |
14 | .\" This manual is distributed in the hope that it will be useful, | |
15 | .\" but WITHOUT ANY WARRANTY; without even the implied warranty of | |
16 | .\" MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
17 | .\" GNU General Public License for more details. | |
18 | .\" | |
19 | .\" You should have received a copy of the GNU General Public | |
c715f741 MK |
20 | .\" License along with this manual; if not, see |
21 | .\" <http://www.gnu.org/licenses/>. | |
6a8d8745 | 22 | .\" %%%LICENSE_END |
fea681da | 23 | .\" |
4b8c67d9 | 24 | .TH GETPWENT_R 3 2017-09-15 "GNU" "Linux Programmer's Manual" |
fea681da MK |
25 | .SH NAME |
26 | getpwent_r, fgetpwent_r \- get passwd file entry reentrantly | |
27 | .SH SYNOPSIS | |
28 | .nf | |
fea681da | 29 | .B #include <pwd.h> |
68e4db0a | 30 | .PP |
fea681da | 31 | .BI "int getpwent_r(struct passwd *" pwbuf ", char *" buf , |
fea681da | 32 | .BI " size_t " buflen ", struct passwd **" pwbufp ); |
68e4db0a | 33 | .PP |
495604c3 | 34 | .BI "int fgetpwent_r(FILE *" stream ", struct passwd *" pwbuf ", char *" buf , |
fea681da | 35 | .BI " size_t " buflen ", struct passwd **" pwbufp ); |
cc4615cc | 36 | .fi |
68e4db0a | 37 | .PP |
cc4615cc MK |
38 | .in -4n |
39 | Feature Test Macro Requirements for glibc (see | |
40 | .BR feature_test_macros (7)): | |
41 | .in | |
68e4db0a | 42 | .PP |
cc4615cc | 43 | .BR getpwent_r (), |
51c612fb MK |
44 | Since glibc 2.19: |
45 | _DEFAULT_SOURCE | |
46 | Glibc 2.19 and earlier: | |
47 | _BSD_SOURCE || _SVID_SOURCE | |
cc4615cc MK |
48 | .br |
49 | .BR fgetpwent_r (): | |
51c612fb MK |
50 | Since glibc 2.19: |
51 | _DEFAULT_SOURCE | |
52 | Glibc 2.19 and earlier: | |
53 | _SVID_SOURCE | |
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54 | .SH DESCRIPTION |
55 | The functions | |
63aa9df0 | 56 | .BR getpwent_r () |
fea681da | 57 | and |
63aa9df0 | 58 | .BR fgetpwent_r () |
fea681da MK |
59 | are the reentrant versions of |
60 | .BR getpwent (3) | |
61 | and | |
62 | .BR fgetpwent (3). | |
63 | The former reads the next passwd entry from the stream initialized by | |
64 | .BR setpwent (3). | |
ef3d4efe | 65 | The latter reads the next passwd entry from |
495604c3 | 66 | .IR stream . |
fea681da MK |
67 | .PP |
68 | The \fIpasswd\fP structure is defined in | |
69 | .I <pwd.h> | |
70 | as follows: | |
51f5698d | 71 | .PP |
bd191423 | 72 | .in +4n |
b8302363 | 73 | .EX |
fea681da | 74 | struct passwd { |
18701562 | 75 | char *pw_name; /* username */ |
cf0a9ace MK |
76 | char *pw_passwd; /* user password */ |
77 | uid_t pw_uid; /* user ID */ | |
78 | gid_t pw_gid; /* group ID */ | |
97724acd | 79 | char *pw_gecos; /* user information */ |
cf0a9ace MK |
80 | char *pw_dir; /* home directory */ |
81 | char *pw_shell; /* shell program */ | |
fea681da | 82 | }; |
b8302363 | 83 | .EE |
bd191423 | 84 | .in |
7f12f117 MK |
85 | .PP |
86 | For more information about the fields of this structure, see | |
87 | .BR passwd (5). | |
847e0d88 | 88 | .PP |
54d75d6c | 89 | The nonreentrant functions return a pointer to static storage, |
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90 | where this static storage contains further pointers to user |
91 | name, password, gecos field, home directory and shell. | |
92 | The reentrant functions described here return all of that in | |
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93 | caller-provided buffers. |
94 | First of all there is the buffer | |
fea681da | 95 | .I pwbuf |
0c2ec4f1 | 96 | that can hold a \fIstruct passwd\fP. |
c13182ef | 97 | And next the buffer |
fea681da MK |
98 | .I buf |
99 | of size | |
100 | .I buflen | |
101 | that can hold additional strings. | |
0c2ec4f1 | 102 | The result of these functions, the \fIstruct passwd\fP read from the stream, |
fea681da | 103 | is stored in the provided buffer |
bd9b2a9c | 104 | .IR *pwbuf , |
0c2ec4f1 | 105 | and a pointer to this \fIstruct passwd\fP is returned in |
bd9b2a9c | 106 | .IR *pwbufp . |
47297adb | 107 | .SH RETURN VALUE |
fea681da | 108 | On success, these functions return 0 and |
bd9b2a9c | 109 | .I *pwbufp |
0c2ec4f1 | 110 | is a pointer to the \fIstruct passwd\fP. |
fea681da | 111 | On error, these functions return an error value and |
bd9b2a9c | 112 | .I *pwbufp |
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113 | is NULL. |
114 | .SH ERRORS | |
115 | .TP | |
116 | .B ENOENT | |
117 | No more entries. | |
118 | .TP | |
119 | .B ERANGE | |
c13182ef MK |
120 | Insufficient buffer space supplied. |
121 | Try again with larger buffer. | |
98a731cd ZL |
122 | .SH ATTRIBUTES |
123 | For an explanation of the terms used in this section, see | |
124 | .BR attributes (7). | |
125 | .TS | |
126 | allbox; | |
127 | lb lb lbw27 | |
128 | l l l. | |
129 | Interface Attribute Value | |
130 | T{ | |
131 | .BR getpwent_r () | |
132 | T} Thread safety MT-Unsafe race:pwent locale | |
133 | T{ | |
134 | .BR fgetpwent_r () | |
135 | T} Thread safety MT-Safe | |
136 | .TE | |
847e0d88 | 137 | .sp 1 |
98a731cd ZL |
138 | In the above table, |
139 | .I pwent | |
140 | in | |
141 | .I race:pwent | |
142 | signifies that if any of the functions | |
143 | .BR setpwent (), | |
144 | .BR getpwent (), | |
145 | .BR endpwent (), | |
146 | or | |
147 | .BR getpwent_r () | |
148 | are used in parallel in different threads of a program, | |
149 | then data races could occur. | |
47297adb | 150 | .SH CONFORMING TO |
2b2581ee MK |
151 | These functions are GNU extensions, done in a style resembling |
152 | the POSIX version of functions like | |
153 | .BR getpwnam_r (3). | |
b5606b27 | 154 | Other systems use the prototype |
51f5698d | 155 | .PP |
088a639b | 156 | .in +4n |
b8302363 | 157 | .EX |
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158 | struct passwd * |
159 | getpwent_r(struct passwd *pwd, char *buf, int buflen); | |
b8302363 | 160 | .EE |
bdd915e2 | 161 | .in |
51f5698d | 162 | .PP |
2b2581ee | 163 | or, better, |
51f5698d | 164 | .PP |
088a639b | 165 | .in +4n |
b8302363 | 166 | .EX |
2b2581ee MK |
167 | int |
168 | getpwent_r(struct passwd *pwd, char *buf, int buflen, | |
169 | FILE **pw_fp); | |
b8302363 | 170 | .EE |
e646a1ba | 171 | .in |
2b2581ee MK |
172 | .SH NOTES |
173 | The function | |
174 | .BR getpwent_r () | |
175 | is not really reentrant since it shares the reading position | |
176 | in the stream with all other threads. | |
fea681da | 177 | .SH EXAMPLE |
bdd915e2 | 178 | .EX |
fea681da MK |
179 | #define _GNU_SOURCE |
180 | #include <pwd.h> | |
181 | #include <stdio.h> | |
182 | #define BUFLEN 4096 | |
183 | ||
c13182ef MK |
184 | int |
185 | main(void) | |
cf0a9ace MK |
186 | { |
187 | struct passwd pw, *pwp; | |
188 | char buf[BUFLEN]; | |
189 | int i; | |
fea681da | 190 | |
cf0a9ace MK |
191 | setpwent(); |
192 | while (1) { | |
193 | i = getpwent_r(&pw, buf, BUFLEN, &pwp); | |
194 | if (i) | |
195 | break; | |
31a6818e | 196 | printf("%s (%d)\etHOME %s\etSHELL %s\en", pwp\->pw_name, |
29059a65 | 197 | pwp\->pw_uid, pwp\->pw_dir, pwp\->pw_shell); |
cf0a9ace MK |
198 | } |
199 | endpwent(); | |
5bc8c34c | 200 | exit(EXIT_SUCCESS); |
fea681da | 201 | } |
bdd915e2 | 202 | .EE |
fea681da MK |
203 | .\" perhaps add error checking - should use strerror_r |
204 | .\" #include <errno.h> | |
205 | .\" #include <stdlib.h> | |
206 | .\" if (i) { | |
207 | .\" if (i == ENOENT) | |
208 | .\" break; | |
209 | .\" printf("getpwent_r: %s", strerror(i)); | |
4c44ffe5 | 210 | .\" exit(EXIT_SUCCESS); |
fea681da | 211 | .\" } |
47297adb | 212 | .SH SEE ALSO |
fea681da MK |
213 | .BR fgetpwent (3), |
214 | .BR getpw (3), | |
215 | .BR getpwent (3), | |
216 | .BR getpwnam (3), | |
217 | .BR getpwuid (3), | |
218 | .BR putpwent (3), | |
cc4615cc | 219 | .BR passwd (5) |