src/bin/lttng/utils.c

   1 /*
   2  * Copyright (c)  2011 David Goulet <david.goulet@polymtl.ca>
   3  *
   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.
   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
  18 #define _GNU_SOURCE
  19 #include <stdlib.h>
  20 #include <ctype.h>
  21 #include <limits.h>
  22
  23 #include <common/error.h>
  24 #include <common/utils.h>
  25
  26 #include "conf.h"
  27 #include "utils.h"
  28 #include "command.h"
  29
  30 /*
  31  *  get_session_name
  32  *
  33  *  Return allocated string with the session name found in the config
  34  *  directory.
  35  */
  36 char *get_session_name(void)
  37 {
  38         char *path, *session_name = NULL;
  39
  40         /* Get path to config file */
  41         path = utils_get_home_dir();
  42         if (path == NULL) {
  43                 goto error;
  44         }
  45
  46         /* Get session name from config */
  47         session_name = config_read_session_name(path);
  48         if (session_name == NULL) {
  49                 goto error;
  50         }
  51
  52         DBG2("Config file path found: %s", path);
  53         DBG("Session name found: %s", session_name);
  54         return session_name;
  55
  56 error:
  57         return NULL;
  58 }
  59
  60 /*
  61  *  list_commands
  62  *
  63  *  List commands line by line. This is mostly for bash auto completion and to
  64  *  avoid difficult parsing.
  65  */
  66 void list_commands(struct cmd_struct *commands, FILE *ofp)
  67 {
  68         int i = 0;
  69         struct cmd_struct *cmd = NULL;
  70
  71         cmd = &commands[i];
  72         while (cmd->name != NULL) {
  73                 fprintf(ofp, "%s\n", cmd->name);
  74                 i++;
  75                 cmd = &commands[i];
  76         }
  77 }
  78
  79 /*
  80  * list_cmd_options
  81  *
  82  * Prints a simple list of the options available to a command. This is intended
  83  * to be easily parsed for bash completion.
  84  */
  85 void list_cmd_options(FILE *ofp, struct poptOption *options)
  86 {
  87         int i;
  88         struct poptOption *option = NULL;
  89
  90         for (i = 0; options[i].longName != NULL; i++) {
  91                 option = &options[i];
  92
  93                 fprintf(ofp, "--%s\n", option->longName);
  94
  95                 if (isprint(option->shortName)) {
  96                         fprintf(ofp, "-%c\n", option->shortName);
  97                 }
  98         }
  99 }
 100
 101 /*
 102  * fls: returns the position of the most significant bit.
 103  * Returns 0 if no bit is set, else returns the position of the most
 104  * significant bit (from 1 to 32 on 32-bit, from 1 to 64 on 64-bit).
 105  */
 106 #if defined(__i386) || defined(__x86_64)
 107 static inline
 108 unsigned int fls_u32(uint32_t x)
 109 {
 110         int r;
 111
 112         asm("bsrl %1,%0\n\t"
 113             "jnz 1f\n\t"
 114             "movl $-1,%0\n\t"
 115             "1:\n\t"
 116             : "=r" (r) : "rm" (x));
 117         return r + 1;
 118 }
 119 #define HAS_FLS_U32
 120 #endif
 121
 122 #if defined(__x86_64)
 123 static inline
 124 unsigned int fls_u64(uint64_t x)
 125 {
 126         long r;
 127
 128         asm("bsrq %1,%0\n\t"
 129             "jnz 1f\n\t"
 130             "movq $-1,%0\n\t"
 131             "1:\n\t"
 132             : "=r" (r) : "rm" (x));
 133         return r + 1;
 134 }
 135 #define HAS_FLS_U64
 136 #endif
 137
 138 #ifndef HAS_FLS_U64
 139 static __attribute__((unused))
 140 unsigned int fls_u64(uint64_t x)
 141 {
 142         unsigned int r = 64;
 143
 144         if (!x)
 145                 return 0;
 146
 147         if (!(x & 0xFFFFFFFF00000000ULL)) {
 148                 x <<= 32;
 149                 r -= 32;
 150         }
 151         if (!(x & 0xFFFF000000000000ULL)) {
 152                 x <<= 16;
 153                 r -= 16;
 154         }
 155         if (!(x & 0xFF00000000000000ULL)) {
 156                 x <<= 8;
 157                 r -= 8;
 158         }
 159         if (!(x & 0xF000000000000000ULL)) {
 160                 x <<= 4;
 161                 r -= 4;
 162         }
 163         if (!(x & 0xC000000000000000ULL)) {
 164                 x <<= 2;
 165                 r -= 2;
 166         }
 167         if (!(x & 0x8000000000000000ULL)) {
 168                 x <<= 1;
 169                 r -= 1;
 170         }
 171         return r;
 172 }
 173 #endif
 174
 175 #ifndef HAS_FLS_U32
 176 static __attribute__((unused))
 177 unsigned int fls_u32(uint32_t x)
 178 {
 179         unsigned int r = 32;
 180
 181         if (!x)
 182                 return 0;
 183         if (!(x & 0xFFFF0000U)) {
 184                 x <<= 16;
 185                 r -= 16;
 186         }
 187         if (!(x & 0xFF000000U)) {
 188                 x <<= 8;
 189                 r -= 8;
 190         }
 191         if (!(x & 0xF0000000U)) {
 192                 x <<= 4;
 193                 r -= 4;
 194         }
 195         if (!(x & 0xC0000000U)) {
 196                 x <<= 2;
 197                 r -= 2;
 198         }
 199         if (!(x & 0x80000000U)) {
 200                 x <<= 1;
 201                 r -= 1;
 202         }
 203         return r;
 204 }
 205 #endif
 206
 207 static
 208 unsigned int fls_ulong(unsigned long x)
 209 {
 210 #if (CAA_BITS_PER_LONG == 32)
 211         return fls_u32(x);
 212 #else
 213         return fls_u64(x);
 214 #endif
 215 }
 216
 217 /*
 218  * Return the minimum order for which x <= (1UL << order).
 219  * Return -1 if x is 0.
 220  */
 221 int get_count_order_u32(uint32_t x)
 222 {
 223         if (!x)
 224                 return -1;
 225
 226         return fls_u32(x - 1);
 227 }
 228
 229 /*
 230  * Return the minimum order for which x <= (1UL << order).
 231  * Return -1 if x is 0.
 232  */
 233 int get_count_order_u64(uint64_t x)
 234 {
 235         if (!x)
 236                 return -1;
 237
 238         return fls_u64(x - 1);
 239 }
 240
 241 /*
 242  * Return the minimum order for which x <= (1UL << order).
 243  * Return -1 if x is 0.
 244  */
 245 int get_count_order_ulong(unsigned long x)
 246 {
 247         if (!x)
 248                 return -1;
 249
 250         return fls_ulong(x - 1);
 251 }