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Commit | Line | Data |
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3185942a JA |
1 | /* zread - read data from file descriptor into buffer with retries */ |
2 | ||
7117c2d2 | 3 | /* Copyright (C) 1999-2002 Free Software Foundation, Inc. |
bb70624e JA |
4 | |
5 | This file is part of GNU Bash, the Bourne Again SHell. | |
6 | ||
3185942a JA |
7 | Bash is free software: you can redistribute it and/or modify |
8 | it under the terms of the GNU General Public License as published by | |
9 | the Free Software Foundation, either version 3 of the License, or | |
10 | (at your option) any later version. | |
11 | ||
12 | Bash is distributed in the hope that it will be useful, | |
13 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
14 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
15 | GNU General Public License for more details. | |
16 | ||
17 | You should have received a copy of the GNU General Public License | |
18 | along with Bash. If not, see <http://www.gnu.org/licenses/>. | |
19 | */ | |
bb70624e JA |
20 | |
21 | #include <config.h> | |
22 | ||
23 | #include <sys/types.h> | |
24 | ||
25 | #if defined (HAVE_UNISTD_H) | |
26 | # include <unistd.h> | |
27 | #endif | |
28 | ||
ac50fbac | 29 | #include <signal.h> |
bb70624e JA |
30 | #include <errno.h> |
31 | ||
32 | #if !defined (errno) | |
33 | extern int errno; | |
34 | #endif | |
35 | ||
36 | #ifndef SEEK_CUR | |
37 | # define SEEK_CUR 1 | |
38 | #endif | |
39 | ||
ac50fbac CR |
40 | extern void check_signals_and_traps (void); |
41 | extern int signal_is_trapped (int); | |
42 | ||
bb70624e JA |
43 | /* Read LEN bytes from FD into BUF. Retry the read on EINTR. Any other |
44 | error causes the loop to break. */ | |
f73dda09 | 45 | ssize_t |
bb70624e JA |
46 | zread (fd, buf, len) |
47 | int fd; | |
48 | char *buf; | |
49 | size_t len; | |
50 | { | |
f73dda09 | 51 | ssize_t r; |
bb70624e | 52 | |
ac50fbac CR |
53 | #if 0 |
54 | #if defined (HAVE_SIGINTERRUPT) | |
55 | if (signal_is_trapped (SIGCHLD)) | |
56 | siginterrupt (SIGCHLD, 1); | |
57 | #endif | |
58 | #endif | |
59 | ||
bb70624e | 60 | while ((r = read (fd, buf, len)) < 0 && errno == EINTR) |
ac50fbac CR |
61 | check_signals_and_traps (); /* XXX - should it be check_signals()? */ |
62 | ||
63 | #if 0 | |
64 | #if defined (HAVE_SIGINTERRUPT) | |
65 | siginterrupt (SIGCHLD, 0); | |
66 | #endif | |
67 | #endif | |
68 | ||
bb70624e JA |
69 | return r; |
70 | } | |
71 | ||
72 | /* Read LEN bytes from FD into BUF. Retry the read on EINTR, up to three | |
73 | interrupts. Any other error causes the loop to break. */ | |
74 | ||
75 | #ifdef NUM_INTR | |
76 | # undef NUM_INTR | |
77 | #endif | |
78 | #define NUM_INTR 3 | |
79 | ||
f73dda09 | 80 | ssize_t |
17345e5a | 81 | zreadretry (fd, buf, len) |
bb70624e JA |
82 | int fd; |
83 | char *buf; | |
84 | size_t len; | |
85 | { | |
f73dda09 JA |
86 | ssize_t r; |
87 | int nintr; | |
bb70624e JA |
88 | |
89 | for (nintr = 0; ; ) | |
90 | { | |
91 | r = read (fd, buf, len); | |
92 | if (r >= 0) | |
28ef6c31 | 93 | return r; |
bb70624e JA |
94 | if (r == -1 && errno == EINTR) |
95 | { | |
17345e5a | 96 | if (++nintr >= NUM_INTR) |
bb70624e JA |
97 | return -1; |
98 | continue; | |
99 | } | |
100 | return r; | |
101 | } | |
102 | } | |
103 | ||
17345e5a JA |
104 | /* Call read(2) and allow it to be interrupted. Just a stub for now. */ |
105 | ssize_t | |
106 | zreadintr (fd, buf, len) | |
107 | int fd; | |
108 | char *buf; | |
109 | size_t len; | |
110 | { | |
111 | return (read (fd, buf, len)); | |
112 | } | |
113 | ||
bb70624e JA |
114 | /* Read one character from FD and return it in CP. Return values are as |
115 | in read(2). This does some local buffering to avoid many one-character | |
116 | calls to read(2), like those the `read' builtin performs. */ | |
117 | ||
f73dda09 JA |
118 | static char lbuf[128]; |
119 | static size_t lind, lused; | |
bb70624e | 120 | |
f73dda09 | 121 | ssize_t |
bb70624e JA |
122 | zreadc (fd, cp) |
123 | int fd; | |
124 | char *cp; | |
125 | { | |
f73dda09 | 126 | ssize_t nr; |
bb70624e JA |
127 | |
128 | if (lind == lused || lused == 0) | |
129 | { | |
f73dda09 | 130 | nr = zread (fd, lbuf, sizeof (lbuf)); |
bb70624e | 131 | lind = 0; |
f73dda09 JA |
132 | if (nr <= 0) |
133 | { | |
134 | lused = 0; | |
135 | return nr; | |
136 | } | |
137 | lused = nr; | |
bb70624e JA |
138 | } |
139 | if (cp) | |
f73dda09 | 140 | *cp = lbuf[lind++]; |
bb70624e JA |
141 | return 1; |
142 | } | |
143 | ||
17345e5a JA |
144 | /* Don't mix calls to zreadc and zreadcintr in the same function, since they |
145 | use the same local buffer. */ | |
146 | ssize_t | |
147 | zreadcintr (fd, cp) | |
148 | int fd; | |
149 | char *cp; | |
150 | { | |
151 | ssize_t nr; | |
152 | ||
153 | if (lind == lused || lused == 0) | |
154 | { | |
155 | nr = zreadintr (fd, lbuf, sizeof (lbuf)); | |
156 | lind = 0; | |
157 | if (nr <= 0) | |
158 | { | |
159 | lused = 0; | |
160 | return nr; | |
161 | } | |
162 | lused = nr; | |
163 | } | |
164 | if (cp) | |
165 | *cp = lbuf[lind++]; | |
166 | return 1; | |
167 | } | |
168 | ||
ac50fbac CR |
169 | /* Like zreadc, but read a specified number of characters at a time. Used |
170 | for `read -N'. */ | |
171 | ssize_t | |
172 | zreadn (fd, cp, len) | |
173 | int fd; | |
174 | char *cp; | |
175 | size_t len; | |
176 | { | |
177 | ssize_t nr; | |
178 | ||
179 | if (lind == lused || lused == 0) | |
180 | { | |
181 | if (len > sizeof (lbuf)) | |
182 | len = sizeof (lbuf); | |
183 | nr = zread (fd, lbuf, len); | |
184 | lind = 0; | |
185 | if (nr <= 0) | |
186 | { | |
187 | lused = 0; | |
188 | return nr; | |
189 | } | |
190 | lused = nr; | |
191 | } | |
192 | if (cp) | |
193 | *cp = lbuf[lind++]; | |
194 | return 1; | |
195 | } | |
196 | ||
bb70624e JA |
197 | void |
198 | zreset () | |
199 | { | |
200 | lind = lused = 0; | |
201 | } | |
202 | ||
203 | /* Sync the seek pointer for FD so that the kernel's idea of the last char | |
204 | read is the last char returned by zreadc. */ | |
205 | void | |
206 | zsyncfd (fd) | |
207 | int fd; | |
208 | { | |
ea6616c0 | 209 | off_t off, r; |
bb70624e JA |
210 | |
211 | off = lused - lind; | |
95732b49 | 212 | r = 0; |
bb70624e | 213 | if (off > 0) |
95732b49 JA |
214 | r = lseek (fd, -off, SEEK_CUR); |
215 | ||
ea6616c0 | 216 | if (r != -1) |
95732b49 | 217 | lused = lind = 0; |
bb70624e | 218 | } |