Commit | Line | Data |
---|---|---|
33b14136 | 1 | /* |
ab5be9fa | 2 | * Copyright (C) 2013 Mathieu Desnoyers <mathieu.desnoyers@efficios.com> |
33b14136 | 3 | * |
ab5be9fa | 4 | * SPDX-License-Identifier: LGPL-2.1-only |
33b14136 | 5 | * |
33b14136 MD |
6 | */ |
7 | ||
6c1c0768 | 8 | #define _LGPL_SOURCE |
6cd525e8 | 9 | #include <assert.h> |
636ae5db | 10 | #include <limits.h> |
aeb16260 DG |
11 | #include <unistd.h> |
12 | ||
edf4b93e MJ |
13 | #include <common/compat/errno.h> |
14 | ||
33b14136 MD |
15 | #include "readwrite.h" |
16 | ||
17 | /* | |
18 | * lttng_read and lttng_write take care of EINTR and partial read/write. | |
19 | * Upon success, they return the "count" received as parameter. | |
20 | * They can return a negative value if an error occurs. | |
21 | * If a value lower than the requested "count" is returned, it means an | |
83f4233d | 22 | * error occurred. |
33b14136 MD |
23 | * The error can be checked by querying errno. |
24 | */ | |
73ec1cf9 | 25 | LTTNG_HIDDEN |
33b14136 MD |
26 | ssize_t lttng_read(int fd, void *buf, size_t count) |
27 | { | |
28 | size_t i = 0; | |
29 | ssize_t ret; | |
30 | ||
aeb16260 DG |
31 | assert(buf); |
32 | ||
636ae5db DG |
33 | /* |
34 | * Deny a read count that can be bigger then the returned value max size. | |
35 | * This makes the function to never return an overflow value. | |
36 | */ | |
37 | if (count > SSIZE_MAX) { | |
38 | return -EINVAL; | |
39 | } | |
40 | ||
33b14136 | 41 | do { |
6cd525e8 | 42 | ret = read(fd, buf + i, count - i); |
33b14136 MD |
43 | if (ret < 0) { |
44 | if (errno == EINTR) { | |
45 | continue; /* retry operation */ | |
46 | } else { | |
47 | goto error; | |
48 | } | |
49 | } | |
50 | i += ret; | |
51 | assert(i <= count); | |
52 | } while (count - i > 0 && ret > 0); | |
53 | return i; | |
54 | ||
55 | error: | |
56 | if (i == 0) { | |
57 | return -1; | |
58 | } else { | |
59 | return i; | |
60 | } | |
61 | } | |
62 | ||
73ec1cf9 | 63 | LTTNG_HIDDEN |
33b14136 MD |
64 | ssize_t lttng_write(int fd, const void *buf, size_t count) |
65 | { | |
66 | size_t i = 0; | |
67 | ssize_t ret; | |
68 | ||
aeb16260 DG |
69 | assert(buf); |
70 | ||
636ae5db DG |
71 | /* |
72 | * Deny a write count that can be bigger then the returned value max size. | |
73 | * This makes the function to never return an overflow value. | |
74 | */ | |
75 | if (count > SSIZE_MAX) { | |
76 | return -EINVAL; | |
77 | } | |
78 | ||
33b14136 | 79 | do { |
6cd525e8 | 80 | ret = write(fd, buf + i, count - i); |
33b14136 MD |
81 | if (ret < 0) { |
82 | if (errno == EINTR) { | |
83 | continue; /* retry operation */ | |
84 | } else { | |
85 | goto error; | |
86 | } | |
87 | } | |
88 | i += ret; | |
89 | assert(i <= count); | |
90 | } while (count - i > 0 && ret > 0); | |
91 | return i; | |
92 | ||
93 | error: | |
94 | if (i == 0) { | |
95 | return -1; | |
96 | } else { | |
97 | return i; | |
98 | } | |
99 | } |