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 <assert.h>
  20 #include <stdlib.h>
  21 #include <ctype.h>
  22 #include <limits.h>
  23
  24 #include <common/error.h>
  25 #include <common/utils.h>
  26
  27 #include "conf.h"
  28 #include "utils.h"
  29 #include "command.h"
  30
  31 static const char *str_kernel = "Kernel";
  32 static const char *str_ust = "UST";
  33 static const char *str_jul = "JUL";
  34
  35 /*
  36  *  get_session_name
  37  *
  38  *  Return allocated string with the session name found in the config
  39  *  directory.
  40  */
  41 char *get_session_name(void)
  42 {
  43         char *path, *session_name = NULL;
  44
  45         /* Get path to config file */
  46         path = utils_get_home_dir();
  47         if (path == NULL) {
  48                 goto error;
  49         }
  50
  51         /* Get session name from config */
  52         session_name = config_read_session_name(path);
  53         if (session_name == NULL) {
  54                 goto error;
  55         }
  56
  57         DBG2("Config file path found: %s", path);
  58         DBG("Session name found: %s", session_name);
  59         return session_name;
  60
  61 error:
  62         return NULL;
  63 }
  64
  65 /*
  66  *  list_commands
  67  *
  68  *  List commands line by line. This is mostly for bash auto completion and to
  69  *  avoid difficult parsing.
  70  */
  71 void list_commands(struct cmd_struct *commands, FILE *ofp)
  72 {
  73         int i = 0;
  74         struct cmd_struct *cmd = NULL;
  75
  76         cmd = &commands[i];
  77         while (cmd->name != NULL) {
  78                 fprintf(ofp, "%s\n", cmd->name);
  79                 i++;
  80                 cmd = &commands[i];
  81         }
  82 }
  83
  84 /*
  85  * list_cmd_options
  86  *
  87  * Prints a simple list of the options available to a command. This is intended
  88  * to be easily parsed for bash completion.
  89  */
  90 void list_cmd_options(FILE *ofp, struct poptOption *options)
  91 {
  92         int i;
  93         struct poptOption *option = NULL;
  94
  95         for (i = 0; options[i].longName != NULL; i++) {
  96                 option = &options[i];
  97
  98                 fprintf(ofp, "--%s\n", option->longName);
  99
 100                 if (isprint(option->shortName)) {
 101                         fprintf(ofp, "-%c\n", option->shortName);
 102                 }
 103         }
 104 }
 105
 106 /*
 107  * fls: returns the position of the most significant bit.
 108  * Returns 0 if no bit is set, else returns the position of the most
 109  * significant bit (from 1 to 32 on 32-bit, from 1 to 64 on 64-bit).
 110  */
 111 #if defined(__i386) || defined(__x86_64)
 112 static inline
 113 unsigned int fls_u32(uint32_t x)
 114 {
 115         int r;
 116
 117         asm("bsrl %1,%0\n\t"
 118             "jnz 1f\n\t"
 119             "movl $-1,%0\n\t"
 120             "1:\n\t"
 121             : "=r" (r) : "rm" (x));
 122         return r + 1;
 123 }
 124 #define HAS_FLS_U32
 125 #endif
 126
 127 #if defined(__x86_64)
 128 static inline
 129 unsigned int fls_u64(uint64_t x)
 130 {
 131         long r;
 132
 133         asm("bsrq %1,%0\n\t"
 134             "jnz 1f\n\t"
 135             "movq $-1,%0\n\t"
 136             "1:\n\t"
 137             : "=r" (r) : "rm" (x));
 138         return r + 1;
 139 }
 140 #define HAS_FLS_U64
 141 #endif
 142
 143 #ifndef HAS_FLS_U64
 144 static __attribute__((unused))
 145 unsigned int fls_u64(uint64_t x)
 146 {
 147         unsigned int r = 64;
 148
 149         if (!x)
 150                 return 0;
 151
 152         if (!(x & 0xFFFFFFFF00000000ULL)) {
 153                 x <<= 32;
 154                 r -= 32;
 155         }
 156         if (!(x & 0xFFFF000000000000ULL)) {
 157                 x <<= 16;
 158                 r -= 16;
 159         }
 160         if (!(x & 0xFF00000000000000ULL)) {
 161                 x <<= 8;
 162                 r -= 8;
 163         }
 164         if (!(x & 0xF000000000000000ULL)) {
 165                 x <<= 4;
 166                 r -= 4;
 167         }
 168         if (!(x & 0xC000000000000000ULL)) {
 169                 x <<= 2;
 170                 r -= 2;
 171         }
 172         if (!(x & 0x8000000000000000ULL)) {
 173                 x <<= 1;
 174                 r -= 1;
 175         }
 176         return r;
 177 }
 178 #endif
 179
 180 #ifndef HAS_FLS_U32
 181 static __attribute__((unused))
 182 unsigned int fls_u32(uint32_t x)
 183 {
 184         unsigned int r = 32;
 185
 186         if (!x)
 187                 return 0;
 188         if (!(x & 0xFFFF0000U)) {
 189                 x <<= 16;
 190                 r -= 16;
 191         }
 192         if (!(x & 0xFF000000U)) {
 193                 x <<= 8;
 194                 r -= 8;
 195         }
 196         if (!(x & 0xF0000000U)) {
 197                 x <<= 4;
 198                 r -= 4;
 199         }
 200         if (!(x & 0xC0000000U)) {
 201                 x <<= 2;
 202                 r -= 2;
 203         }
 204         if (!(x & 0x80000000U)) {
 205                 x <<= 1;
 206                 r -= 1;
 207         }
 208         return r;
 209 }
 210 #endif
 211
 212 static
 213 unsigned int fls_ulong(unsigned long x)
 214 {
 215 #if (CAA_BITS_PER_LONG == 32)
 216         return fls_u32(x);
 217 #else
 218         return fls_u64(x);
 219 #endif
 220 }
 221
 222 /*
 223  * Return the minimum order for which x <= (1UL << order).
 224  * Return -1 if x is 0.
 225  */
 226 int get_count_order_u32(uint32_t x)
 227 {
 228         if (!x)
 229                 return -1;
 230
 231         return fls_u32(x - 1);
 232 }
 233
 234 /*
 235  * Return the minimum order for which x <= (1UL << order).
 236  * Return -1 if x is 0.
 237  */
 238 int get_count_order_u64(uint64_t x)
 239 {
 240         if (!x)
 241                 return -1;
 242
 243         return fls_u64(x - 1);
 244 }
 245
 246 /*
 247  * Return the minimum order for which x <= (1UL << order).
 248  * Return -1 if x is 0.
 249  */
 250 int get_count_order_ulong(unsigned long x)
 251 {
 252         if (!x)
 253                 return -1;
 254
 255         return fls_ulong(x - 1);
 256 }
 257
 258 const char *get_domain_str(enum lttng_domain_type domain)
 259 {
 260         const char *str_dom;
 261
 262         switch (domain) {
 263         case LTTNG_DOMAIN_KERNEL:
 264                 str_dom = str_kernel;
 265                 break;
 266         case LTTNG_DOMAIN_UST:
 267                 str_dom = str_ust;
 268                 break;
 269         case LTTNG_DOMAIN_JUL:
 270                 str_dom = str_jul;
 271                 break;
 272         default:
 273                 /* Should not have an unknown domain or else define it. */
 274                 assert(0);
 275         }
 276
 277         return str_dom;
 278 }