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1 | #ifndef _LTTNG_CTL_MEMSTREAM_H |
2 | #define _LTTNG_CTL_MEMSTREAM_H | |
3 | ||
4 | /* | |
5 | * src/lib/lttng-ctl/memstream.h | |
6 | * | |
7 | * Copyright 2012 (c) - Mathieu Desnoyers <mathieu.desnoyers@efficios.com> | |
8 | * | |
9 | * memstream compatibility layer. | |
10 | * | |
11 | * Permission is hereby granted, free of charge, to any person obtaining a copy | |
12 | * of this software and associated documentation files (the "Software"), to deal | |
13 | * in the Software without restriction, including without limitation the rights | |
14 | * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell | |
15 | * copies of the Software, and to permit persons to whom the Software is | |
16 | * furnished to do so, subject to the following conditions: | |
17 | * | |
18 | * The above copyright notice and this permission notice shall be included in | |
19 | * all copies or substantial portions of the Software. | |
20 | */ | |
21 | ||
22 | #define _GNU_SOURCE | |
23 | #include <config.h> | |
24 | ||
25 | #ifdef LTTNG_HAVE_FMEMOPEN | |
26 | #include <stdio.h> | |
27 | ||
28 | static inline | |
29 | FILE *lttng_fmemopen(void *buf, size_t size, const char *mode) | |
30 | { | |
31 | return fmemopen(buf, size, mode); | |
32 | } | |
33 | ||
34 | #else /* LTTNG_HAVE_FMEMOPEN */ | |
35 | ||
36 | #include <stdlib.h> | |
37 | #include <stdio.h> | |
38 | ||
39 | /* | |
40 | * Fallback for systems which don't have fmemopen. Copy buffer to a | |
41 | * temporary file, and use that file as FILE * input. | |
42 | */ | |
43 | static inline | |
44 | FILE *lttng_fmemopen(void *buf, size_t size, const char *mode) | |
45 | { | |
46 | char tmpname[PATH_MAX]; | |
47 | size_t len; | |
48 | FILE *fp; | |
49 | int ret; | |
50 | ||
51 | /* | |
52 | * Support reading only. | |
53 | */ | |
54 | if (strcmp(mode, "rb") != 0) { | |
55 | return NULL; | |
56 | } | |
57 | strncpy(tmpname, "/tmp/lttng-tmp-XXXXXX", PATH_MAX); | |
58 | ret = mkstemp(tmpname); | |
59 | if (ret < 0) { | |
60 | return NULL; | |
61 | } | |
62 | /* | |
63 | * We need to write to the file. | |
64 | */ | |
65 | fp = fdopen(ret, "w+"); | |
66 | if (!fp) { | |
67 | goto error_unlink; | |
68 | } | |
69 | /* Copy the entire buffer to the file */ | |
70 | len = fwrite(buf, sizeof(char), size, fp); | |
71 | if (len != size) { | |
72 | goto error_close; | |
73 | } | |
74 | ret = fseek(fp, 0L, SEEK_SET); | |
75 | if (ret < 0) { | |
76 | perror("fseek"); | |
77 | goto error_close; | |
78 | } | |
79 | /* We keep the handle open, but can unlink the file on the VFS. */ | |
80 | ret = unlink(tmpname); | |
81 | if (ret < 0) { | |
82 | perror("unlink"); | |
83 | } | |
84 | return fp; | |
85 | ||
86 | error_close: | |
87 | ret = fclose(fp); | |
88 | if (ret < 0) { | |
89 | perror("close"); | |
90 | } | |
91 | error_unlink: | |
92 | ret = unlink(tmpname); | |
93 | if (ret < 0) { | |
94 | perror("unlink"); | |
95 | } | |
96 | return NULL; | |
97 | } | |
98 | ||
99 | #endif /* LTTNG_HAVE_FMEMOPEN */ | |
100 | ||
101 | #ifdef LTTNG_HAVE_OPEN_MEMSTREAM | |
102 | ||
103 | #include <stdio.h> | |
104 | ||
105 | static inline | |
106 | FILE *lttng_open_memstream(char **ptr, size_t *sizeloc) | |
107 | { | |
108 | return open_memstream(ptr, sizeloc); | |
109 | } | |
110 | ||
111 | static inline | |
112 | int lttng_close_memstream(char **buf, size_t *size, FILE *fp) | |
113 | { | |
114 | return fclose(fp); | |
115 | } | |
116 | ||
117 | #else /* LTTNG_HAVE_OPEN_MEMSTREAM */ | |
118 | ||
119 | #include <stdlib.h> | |
120 | #include <stdio.h> | |
121 | ||
122 | /* | |
123 | * Fallback for systems which don't have open_memstream. Create FILE * | |
124 | * with lttng_open_memstream, but require call to | |
125 | * lttng_close_memstream to flush all data written to the FILE * | |
126 | * into the buffer (which we allocate). | |
127 | */ | |
128 | static inline | |
129 | FILE *lttng_open_memstream(char **ptr, size_t *sizeloc) | |
130 | { | |
131 | char tmpname[PATH_MAX]; | |
132 | int ret; | |
133 | FILE *fp; | |
134 | ||
135 | strncpy(tmpname, "/tmp/lttng-tmp-XXXXXX", PATH_MAX); | |
136 | ret = mkstemp(tmpname); | |
137 | if (ret < 0) { | |
138 | return NULL; | |
139 | } | |
140 | fp = fdopen(ret, "w+"); | |
141 | if (!fp) { | |
142 | goto error_unlink; | |
143 | } | |
144 | /* | |
145 | * lttng_flush_memstream will update the buffer content | |
146 | * with read from fp. No need to keep the file around, just the | |
147 | * handle. | |
148 | */ | |
149 | ret = unlink(tmpname); | |
150 | if (ret < 0) { | |
151 | perror("unlink"); | |
152 | } | |
153 | return fp; | |
154 | ||
155 | error_unlink: | |
156 | ret = unlink(tmpname); | |
157 | if (ret < 0) { | |
158 | perror("unlink"); | |
159 | } | |
160 | return NULL; | |
161 | } | |
162 | ||
163 | /* Get file size, allocate buffer, copy. */ | |
164 | static inline | |
165 | int lttng_close_memstream(char **buf, size_t *size, FILE *fp) | |
166 | { | |
167 | size_t len, n; | |
168 | long pos; | |
169 | int ret; | |
170 | ||
171 | ret = fflush(fp); | |
172 | if (ret < 0) { | |
173 | perror("fflush"); | |
174 | return ret; | |
175 | } | |
176 | ret = fseek(fp, 0L, SEEK_END); | |
177 | if (ret < 0) { | |
178 | perror("fseek"); | |
179 | return ret; | |
180 | } | |
181 | pos = ftell(fp); | |
182 | if (ret < 0) { | |
183 | perror("ftell"); | |
184 | return ret; | |
185 | } | |
186 | *size = pos; | |
187 | /* add final \0 */ | |
188 | *buf = calloc(pos + 1, sizeof(char)); | |
189 | if (!*buf) { | |
190 | return -ENOMEM; | |
191 | } | |
192 | ret = fseek(fp, 0L, SEEK_SET); | |
193 | if (ret < 0) { | |
194 | perror("fseek"); | |
195 | goto error_free; | |
196 | } | |
197 | /* Copy the entire file into the buffer */ | |
198 | n = 0; | |
199 | clearerr(fp); | |
200 | while (!feof(fp) && !ferror(fp) && (*size - n > 0)) { | |
201 | len = fread(*buf, sizeof(char), *size - n, fp); | |
202 | n += len; | |
203 | } | |
204 | if (n != *size) { | |
205 | ret = -1; | |
206 | goto error_close; | |
207 | } | |
208 | ret = fclose(fp); | |
209 | if (ret < 0) { | |
210 | perror("fclose"); | |
211 | return ret; | |
212 | } | |
213 | return 0; | |
214 | ||
215 | error_close: | |
216 | ret = fclose(fp); | |
217 | if (ret < 0) { | |
218 | perror("fclose"); | |
219 | } | |
220 | error_free: | |
221 | free(*buf); | |
222 | *buf = NULL; | |
223 | return ret; | |
224 | } | |
225 | ||
226 | #endif /* LTTNG_HAVE_OPEN_MEMSTREAM */ | |
227 | ||
228 | #endif /* _LTTNG_CTL_MEMSTREAM_H */ |