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33b14136 MD |
1 | /* |
2 | * Copyright (C) 2013 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com> | |
3 | * | |
4 | * This library is free software; you can redistribute it and/or modify it | |
5 | * under the terms of the GNU Lesser General Public License, version 2.1 only, | |
6 | * as published by the Free Software Foundation. | |
7 | * | |
8 | * This library is distributed in the hope that it will be useful, but WITHOUT | |
9 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
10 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License | |
11 | * for more details. | |
12 | * | |
13 | * You should have received a copy of the GNU Lesser General Public License | |
14 | * along with this library; if not, write to the Free Software Foundation, | |
15 | * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA | |
16 | */ | |
17 | ||
18 | #include <unistd.h> | |
6cd525e8 MD |
19 | #include <errno.h> |
20 | #include <assert.h> | |
33b14136 MD |
21 | #include "readwrite.h" |
22 | ||
23 | /* | |
24 | * lttng_read and lttng_write take care of EINTR and partial read/write. | |
25 | * Upon success, they return the "count" received as parameter. | |
26 | * They can return a negative value if an error occurs. | |
27 | * If a value lower than the requested "count" is returned, it means an | |
28 | * error occured. | |
29 | * The error can be checked by querying errno. | |
30 | */ | |
31 | ssize_t lttng_read(int fd, void *buf, size_t count) | |
32 | { | |
33 | size_t i = 0; | |
34 | ssize_t ret; | |
35 | ||
36 | do { | |
6cd525e8 | 37 | ret = read(fd, buf + i, count - i); |
33b14136 MD |
38 | if (ret < 0) { |
39 | if (errno == EINTR) { | |
40 | continue; /* retry operation */ | |
41 | } else { | |
42 | goto error; | |
43 | } | |
44 | } | |
45 | i += ret; | |
46 | assert(i <= count); | |
47 | } while (count - i > 0 && ret > 0); | |
48 | return i; | |
49 | ||
50 | error: | |
51 | if (i == 0) { | |
52 | return -1; | |
53 | } else { | |
54 | return i; | |
55 | } | |
56 | } | |
57 | ||
58 | ssize_t lttng_write(int fd, const void *buf, size_t count) | |
59 | { | |
60 | size_t i = 0; | |
61 | ssize_t ret; | |
62 | ||
63 | do { | |
6cd525e8 | 64 | ret = write(fd, buf + i, count - i); |
33b14136 MD |
65 | if (ret < 0) { |
66 | if (errno == EINTR) { | |
67 | continue; /* retry operation */ | |
68 | } else { | |
69 | goto error; | |
70 | } | |
71 | } | |
72 | i += ret; | |
73 | assert(i <= count); | |
74 | } while (count - i > 0 && ret > 0); | |
75 | return i; | |
76 | ||
77 | error: | |
78 | if (i == 0) { | |
79 | return -1; | |
80 | } else { | |
81 | return i; | |
82 | } | |
83 | } |