Fix: remove use of stat()
[lttng-tools.git] / src / bin / lttng / utils.c
CommitLineData
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1/*
2 * Copyright (c) 2011 David Goulet <david.goulet@polymtl.ca>
3 *
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4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License, version 2 only,
6 * as published by the Free Software Foundation.
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7 *
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
11 * GNU General Public License for more details.
12 *
13 * You should have received a copy of the GNU General Public License along
14 * with this program; if not, write to the Free Software Foundation, Inc.,
15 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
16 */
17
4c462e79 18#define _GNU_SOURCE
f3ed775e 19#include <stdlib.h>
679b4943 20#include <ctype.h>
3badf2bf 21#include <limits.h>
f3ed775e 22
db758600 23#include <common/error.h>
f3ed775e 24
beb8c75a 25#include "conf.h"
679b4943 26#include "utils.h"
f3ed775e 27
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28/*
29 * get_session_name
30 *
31 * Return allocated string with the session name found in the config
32 * directory.
33 */
34char *get_session_name(void)
35{
36 char *path, *session_name = NULL;
37
38 /* Get path to config file */
58a97671 39 path = config_get_default_path();
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40 if (path == NULL) {
41 goto error;
42 }
43
44 /* Get session name from config */
45 session_name = config_read_session_name(path);
46 if (session_name == NULL) {
58a97671 47 goto error;
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48 }
49
3183dbb0 50 DBG2("Config file path found: %s", path);
cd80958d 51 DBG("Session name found: %s", session_name);
f3ed775e 52 return session_name;
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53
54error:
55 return NULL;
f3ed775e 56}
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57
58
59/*
60 * list_cmd_options
61 *
62 * Prints a simple list of the options available to a command. This is intended
63 * to be easily parsed for bash completion.
64 */
65void list_cmd_options(FILE *ofp, struct poptOption *options)
66{
67 int i;
68 struct poptOption *option = NULL;
69
70 for (i = 0; options[i].longName != NULL; i++) {
71 option = &options[i];
72
73 fprintf(ofp, "--%s\n", option->longName);
74
75 if (isprint(option->shortName)) {
76 fprintf(ofp, "-%c\n", option->shortName);
77 }
78 }
79}
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80
81/*
82 * fls: returns the position of the most significant bit.
83 * Returns 0 if no bit is set, else returns the position of the most
84 * significant bit (from 1 to 32 on 32-bit, from 1 to 64 on 64-bit).
85 */
86#if defined(__i386) || defined(__x86_64)
87static inline
88unsigned int fls_u32(uint32_t x)
89{
90 int r;
91
92 asm("bsrl %1,%0\n\t"
93 "jnz 1f\n\t"
94 "movl $-1,%0\n\t"
95 "1:\n\t"
96 : "=r" (r) : "rm" (x));
97 return r + 1;
98}
99#define HAS_FLS_U32
100#endif
101
102#if defined(__x86_64)
103static inline
104unsigned int fls_u64(uint64_t x)
105{
106 long r;
107
108 asm("bsrq %1,%0\n\t"
109 "jnz 1f\n\t"
110 "movq $-1,%0\n\t"
111 "1:\n\t"
112 : "=r" (r) : "rm" (x));
113 return r + 1;
114}
115#define HAS_FLS_U64
116#endif
117
118#ifndef HAS_FLS_U64
119static __attribute__((unused))
120unsigned int fls_u64(uint64_t x)
121{
122 unsigned int r = 64;
123
124 if (!x)
125 return 0;
126
127 if (!(x & 0xFFFFFFFF00000000ULL)) {
128 x <<= 32;
129 r -= 32;
130 }
131 if (!(x & 0xFFFF000000000000ULL)) {
132 x <<= 16;
133 r -= 16;
134 }
135 if (!(x & 0xFF00000000000000ULL)) {
136 x <<= 8;
137 r -= 8;
138 }
139 if (!(x & 0xF000000000000000ULL)) {
140 x <<= 4;
141 r -= 4;
142 }
143 if (!(x & 0xC000000000000000ULL)) {
144 x <<= 2;
145 r -= 2;
146 }
147 if (!(x & 0x8000000000000000ULL)) {
148 x <<= 1;
149 r -= 1;
150 }
151 return r;
152}
153#endif
154
155#ifndef HAS_FLS_U32
156static __attribute__((unused))
157unsigned int fls_u32(uint32_t x)
158{
159 unsigned int r = 32;
160
161 if (!x)
162 return 0;
163 if (!(x & 0xFFFF0000U)) {
164 x <<= 16;
165 r -= 16;
166 }
167 if (!(x & 0xFF000000U)) {
168 x <<= 8;
169 r -= 8;
170 }
171 if (!(x & 0xF0000000U)) {
172 x <<= 4;
173 r -= 4;
174 }
175 if (!(x & 0xC0000000U)) {
176 x <<= 2;
177 r -= 2;
178 }
179 if (!(x & 0x80000000U)) {
180 x <<= 1;
181 r -= 1;
182 }
183 return r;
184}
185#endif
186
187static
188unsigned int fls_ulong(unsigned long x)
189{
190#if (CAA_BITS_PER_LONG == 32)
191 return fls_u32(x);
192#else
193 return fls_u64(x);
194#endif
195}
196
197/*
198 * Return the minimum order for which x <= (1UL << order).
199 * Return -1 if x is 0.
200 */
201int get_count_order_u32(uint32_t x)
202{
203 if (!x)
204 return -1;
205
206 return fls_u32(x - 1);
207}
208
209/*
210 * Return the minimum order for which x <= (1UL << order).
211 * Return -1 if x is 0.
212 */
213int get_count_order_u64(uint64_t x)
214{
215 if (!x)
216 return -1;
217
218 return fls_u64(x - 1);
219}
220
221/*
222 * Return the minimum order for which x <= (1UL << order).
223 * Return -1 if x is 0.
224 */
225int get_count_order_ulong(unsigned long x)
226{
227 if (!x)
228 return -1;
229
230 return fls_ulong(x - 1);
231}
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