| 1 | #include <stdarg.h> |
| 2 | |
| 3 | /* LTT flags |
| 4 | * |
| 5 | * LTT_FLAG_TRACE : first arg contains trace to write into. |
| 6 | * (type : struct ltt_trace_struct *) |
| 7 | * LTT_FLAG_CHANNEL : following arg contains channel index to write into. |
| 8 | * (type : uint8_t) |
| 9 | * LTT_FLAG_FORCE : Force write in disabled traces (internal ltt use) |
| 10 | */ |
| 11 | |
| 12 | #define _LTT_FLAG_TRACE 0 |
| 13 | #define _LTT_FLAG_CHANNEL 1 |
| 14 | #define _LTT_FLAG_FORCE 2 |
| 15 | |
| 16 | #define LTT_FLAG_TRACE (1 << _LTT_FLAG_TRACE) |
| 17 | #define LTT_FLAG_CHANNEL (1 << _LTT_FLAG_CHANNEL) |
| 18 | #define LTT_FLAG_FORCE (1 << _LTT_FLAG_FORCE) |
| 19 | |
| 20 | |
| 21 | char *(*ltt_serialize_cb)(char *buffer, const char *fmt, va_list args); |
| 22 | |
| 23 | |
| 24 | static int skip_atoi(const char **s) |
| 25 | { |
| 26 | int i=0; |
| 27 | |
| 28 | while (isdigit(**s)) |
| 29 | i = i*10 + *((*s)++) - '0'; |
| 30 | return i; |
| 31 | } |
| 32 | |
| 33 | /* Inspired from vsnprintf */ |
| 34 | /* New types : |
| 35 | * %r : serialized pointer. |
| 36 | */ |
| 37 | static inline __attribute__((no_instrument_function)) |
| 38 | char *ltt_serialize_data(char *buffer, const char *fmt, va_list args) |
| 39 | { |
| 40 | int len; |
| 41 | const char *s; |
| 42 | int elem_size; /* Size of the integer for 'b' */ |
| 43 | /* Size of the data contained by 'r' */ |
| 44 | int elem_alignment; /* Element alignment for 'r' */ |
| 45 | int qualifier; /* 'h', 'l', or 'L' for integer fields */ |
| 46 | /* 'z' support added 23/7/1999 S.H. */ |
| 47 | /* 'z' changed to 'Z' --davidm 1/25/99 */ |
| 48 | /* 't' added for ptrdiff_t */ |
| 49 | char *str; /* Pointer to write to */ |
| 50 | ltt_serialize_cb cb; |
| 51 | |
| 52 | str = buf; |
| 53 | |
| 54 | for (; *fmt ; ++fmt) { |
| 55 | if (*fmt != '%') { |
| 56 | /* Skip text */ |
| 57 | continue; |
| 58 | } |
| 59 | |
| 60 | /* process flags : ignore standard print formats for now. */ |
| 61 | repeat: |
| 62 | ++fmt; /* this also skips first '%' */ |
| 63 | switch (*fmt) { |
| 64 | case '-': |
| 65 | case '+': |
| 66 | case ' ': |
| 67 | case '#': |
| 68 | case '0': goto repeat; |
| 69 | } |
| 70 | |
| 71 | /* get element size */ |
| 72 | elem_size = -1; |
| 73 | if (isdigit(*fmt)) |
| 74 | elem_size = skip_atoi(&fmt); |
| 75 | else if (*fmt == '*') { |
| 76 | ++fmt; |
| 77 | /* it's the next argument */ |
| 78 | elem_size = va_arg(args, int); |
| 79 | } |
| 80 | |
| 81 | /* get the alignment */ |
| 82 | elem_alignment = -1; |
| 83 | if (*fmt == '.') { |
| 84 | ++fmt; |
| 85 | if (isdigit(*fmt)) |
| 86 | elem_alignment = skip_atoi(&fmt); |
| 87 | else if (*fmt == '*') { |
| 88 | ++fmt; |
| 89 | /* it's the next argument */ |
| 90 | elem_alignment = va_arg(args, int); |
| 91 | } |
| 92 | } |
| 93 | |
| 94 | /* get the conversion qualifier */ |
| 95 | qualifier = -1; |
| 96 | if (*fmt == 'h' || *fmt == 'l' || *fmt == 'L' || |
| 97 | *fmt =='Z' || *fmt == 'z' || *fmt == 't') { |
| 98 | qualifier = *fmt; |
| 99 | ++fmt; |
| 100 | if (qualifier == 'l' && *fmt == 'l') { |
| 101 | qualifier = 'L'; |
| 102 | ++fmt; |
| 103 | } |
| 104 | } |
| 105 | |
| 106 | switch (*fmt) { |
| 107 | case 'c': |
| 108 | if (buffer) |
| 109 | *str = (char) va_arg(args, int); |
| 110 | str += sizeof(char); |
| 111 | continue; |
| 112 | |
| 113 | case 's': |
| 114 | s = va_arg(args, char *); |
| 115 | if ((unsigned long)s < PAGE_SIZE) |
| 116 | s = "<NULL>"; |
| 117 | if (buffer) |
| 118 | strcpy(str, s); |
| 119 | str += strlen(s); |
| 120 | continue; |
| 121 | |
| 122 | case 'p': |
| 123 | str += ltt_align(str, sizeof(void*)); |
| 124 | if (buffer) |
| 125 | *(void**)str = va_arg(args, void *); |
| 126 | continue; |
| 127 | |
| 128 | case 'r': |
| 129 | /* For array, struct, union */ |
| 130 | if (elem_alignment < 0) |
| 131 | elem_alignment = sizeof(void*); |
| 132 | str += ltt_align(str, elem_alignment); |
| 133 | if (elem_size > 0) { |
| 134 | const char *src = va_arg(args, |
| 135 | const char *); |
| 136 | if (buffer) |
| 137 | memcpy(str, src, elem_size); |
| 138 | str += elem_size; |
| 139 | } |
| 140 | continue; |
| 141 | |
| 142 | case 'v': |
| 143 | /* For sequence */ |
| 144 | str += ltt_align(str, sizeof(int)); |
| 145 | if (buffer) |
| 146 | *(int*)str = elem_size; |
| 147 | str += sizeof(int); |
| 148 | if (elem_alignment > 0) |
| 149 | str += ltt_align(str, elem_alignment); |
| 150 | if (elem_size > 0) { |
| 151 | const char *src = va_arg(args, |
| 152 | const char *); |
| 153 | if (buffer) |
| 154 | memcpy(str, src, elem_size); |
| 155 | str += elem_size; |
| 156 | } |
| 157 | continue; |
| 158 | |
| 159 | case 'k': |
| 160 | /* For callback */ |
| 161 | cb = va_arg(args, ltt_serialize_cb); |
| 162 | /* The callback will take as many arguments |
| 163 | * as it needs from args. They won't be |
| 164 | * type verified. */ |
| 165 | str = cb(str, fmt, args); |
| 166 | continue; |
| 167 | |
| 168 | case 'n': |
| 169 | /* FIXME: |
| 170 | * What does C99 say about the overflow case here? */ |
| 171 | if (qualifier == 'l') { |
| 172 | long * ip = va_arg(args, long *); |
| 173 | *ip = (str - buf); |
| 174 | } else if (qualifier == 'Z' || qualifier == 'z') { |
| 175 | size_t * ip = va_arg(args, size_t *); |
| 176 | *ip = (str - buf); |
| 177 | } else { |
| 178 | int * ip = va_arg(args, int *); |
| 179 | *ip = (str - buf); |
| 180 | } |
| 181 | continue; |
| 182 | |
| 183 | case '%': |
| 184 | continue; |
| 185 | |
| 186 | case 'o': |
| 187 | case 'X': |
| 188 | case 'x': |
| 189 | case 'd': |
| 190 | case 'i': |
| 191 | case 'u': |
| 192 | break; |
| 193 | |
| 194 | default: |
| 195 | if (!*fmt) |
| 196 | --fmt; |
| 197 | continue; |
| 198 | } |
| 199 | switch (qualifier) { |
| 200 | case 'L': |
| 201 | str += ltt_align(str, sizeof(long long)); |
| 202 | if (buffer) |
| 203 | *(long long*)str = va_arg(args, long long); |
| 204 | str += sizeof(long long); |
| 205 | break; |
| 206 | case 'l': |
| 207 | str += ltt_align(str, sizeof(long)); |
| 208 | if (buffer) |
| 209 | *(long*)str = va_arg(args, long); |
| 210 | str += sizeof(long); |
| 211 | break; |
| 212 | case 'Z': |
| 213 | case 'z': |
| 214 | str += ltt_align(str, sizeof(size_t)); |
| 215 | if (buffer) |
| 216 | *(size_t*)str = va_arg(args, size_t); |
| 217 | str += sizeof(size_t); |
| 218 | break; |
| 219 | case 't': |
| 220 | str += ltt_align(str, sizeof(ptrdiff_t)); |
| 221 | if (buffer) |
| 222 | *(ptrdiff_t*)str = va_arg(args, ptrdiff_t); |
| 223 | str += sizeof(ptrdiff_t); |
| 224 | break; |
| 225 | case 'h': |
| 226 | str += ltt_align(str, sizeof(short)); |
| 227 | if (buffer) |
| 228 | *(short*)str = (short) va_arg(args, int); |
| 229 | str += sizeof(short); |
| 230 | break; |
| 231 | case 'b': |
| 232 | if (elem_size > 0) |
| 233 | str += ltt_align(str, elem_size); |
| 234 | if (buffer) |
| 235 | switch (elem_size) { |
| 236 | case 1: |
| 237 | *(int8_t*)str = (int8_t)va_arg(args, int); |
| 238 | break; |
| 239 | case 2: |
| 240 | *(int16_t*)str = (int16_t)va_arg(args, int); |
| 241 | break; |
| 242 | case 4: |
| 243 | *(int32_t*)str = va_arg(args, int32_t); |
| 244 | break; |
| 245 | case 8: |
| 246 | *(int64_t*)str = va_arg(args, int64_t); |
| 247 | break; |
| 248 | } |
| 249 | str += elem_size; |
| 250 | default: |
| 251 | str += ltt_align(str, sizeof(int)); |
| 252 | if (buffer) |
| 253 | *(int*)str = va_arg(args, int); |
| 254 | str += sizeof(int); |
| 255 | } |
| 256 | } |
| 257 | return str; |
| 258 | } |
| 259 | |
| 260 | /* Calculate data size */ |
| 261 | /* Assume that the padding for alignment starts at a |
| 262 | * sizeof(void *) address. */ |
| 263 | static inline __attribute__((no_instrument_function)) |
| 264 | size_t ltt_get_data_size(ltt_facility_t fID, uint8_t eID, |
| 265 | const char *fmt, va_list args) |
| 266 | { |
| 267 | return (size_t)ltt_serialize_data(NULL, fmt, args); |
| 268 | } |
| 269 | |
| 270 | static inline __attribute__((no_instrument_function)) |
| 271 | void ltt_write_event_data(char *buffer, |
| 272 | ltt_facility_t fID, uint8_t eID, |
| 273 | const char *fmt, va_list args) |
| 274 | { |
| 275 | ltt_serialize_data(buffer, fmt, args); |
| 276 | } |
| 277 | |
| 278 | |
| 279 | __attribute__((no_instrument_function)) |
| 280 | void _vtrace(ltt_facility_t fID, uint8_t eID, long flags, |
| 281 | const char *fmt, va_list args) |
| 282 | { |
| 283 | size_t data_size, slot_size; |
| 284 | int channel_index; |
| 285 | struct ltt_channel_struct *channel; |
| 286 | struct ltt_trace_struct *trace, *dest_trace; |
| 287 | void *transport_data; |
| 288 | uint64_t tsc; |
| 289 | char *buffer; |
| 290 | va_list args_copy; |
| 291 | |
| 292 | /* This test is useful for quickly exiting static tracing when no |
| 293 | * trace is active. */ |
| 294 | if (likely(ltt_traces.num_active_traces == 0 && !(flags & LTT_FLAG_FORCE))) |
| 295 | return; |
| 296 | |
| 297 | preempt_disable(); |
| 298 | ltt_nesting[smp_processor_id()]++; |
| 299 | |
| 300 | if (unlikely(flags & LTT_FLAG_TRACE)) |
| 301 | dest_trace = va_arg(args, struct ltt_trace_struct *); |
| 302 | if (unlikely(flags & LTT_FLAG_CHANNEL)) |
| 303 | channel_index = va_arg(args, int); |
| 304 | else |
| 305 | channel_index = ltt_get_channel_index(fID, eID); |
| 306 | |
| 307 | va_copy(args_copy, args); /* Check : skip 2 st args if trace/ch */ |
| 308 | data_size = ltt_get_data_size(fID, eID, fmt, args_copy); |
| 309 | va_end(args_copy); |
| 310 | |
| 311 | /* Iterate on each traces */ |
| 312 | list_for_each_entry_rcu(trace, <t_traces.head, list) { |
| 313 | if (unlikely(!trace->active && !(flags & LTT_FLAG_FORCE))) |
| 314 | continue; |
| 315 | if (unlikely(flags & LTT_FLAG_TRACE && trace != dest_trace)) |
| 316 | continue; |
| 317 | channel = ltt_get_channel_from_index(trace, channel_index); |
| 318 | /* reserve space : header and data */ |
| 319 | buffer = ltt_reserve_slot(trace, channel, &transport_data, |
| 320 | data_size, &slot_size, &tsc); |
| 321 | if (unlikely(!buffer)) |
| 322 | continue; /* buffer full */ |
| 323 | /* Out-of-order write : header and data */ |
| 324 | buffer = ltt_write_event_header(trace, channel, buffer, |
| 325 | fID, eID, data_size, tsc); |
| 326 | va_copy(args_copy, args); |
| 327 | ltt_write_event_data(buffer, fID, eID, fmt, args_copy); |
| 328 | va_end(args_copy); |
| 329 | /* Out-of-order commit */ |
| 330 | ltt_commit_slot(channel, &transport_data, buffer, slot_size); |
| 331 | } |
| 332 | |
| 333 | ltt_nesting[smp_processor_id()]--; |
| 334 | preempt_enable(); |
| 335 | } |
| 336 | |
| 337 | __attribute__((no_instrument_function)) |
| 338 | void _trace(ltt_facility_t fID, uint8_t eID, long flags, const char *fmt, ...) |
| 339 | { |
| 340 | va_list args; |
| 341 | |
| 342 | va_start(args, fmt); |
| 343 | _vtrace(fID, eID, flags, fmt, args); |
| 344 | va_end(args); |
| 345 | } |
| 346 | |