libbb/procps.c

   1 /* vi: set sw=4 ts=4: */
   2 /*
   3  * Utility routines.
   4  *
   5  * Copyright 1998 by Albert Cahalan; all rights reserved.
   6  * Copyright (C) 2002 by Vladimir Oleynik <dzo@simtreas.ru>
   7  * SELinux support: (c) 2007 by Yuichi Nakamura <ynakam@hitachisoft.jp>
   8  *
   9  * Licensed under GPLv2 or later, see file LICENSE in this source tree.
  10  */
  11
  12 #include "libbb.h"
  13
  14
  15 typedef struct id_to_name_map_t {
  16         uid_t id;
  17         char name[USERNAME_MAX_SIZE];
  18 } id_to_name_map_t;
  19
  20 typedef struct cache_t {
  21         id_to_name_map_t *cache;
  22         int size;
  23 } cache_t;
  24
  25 static cache_t username, groupname;
  26
  27 static void clear_cache(cache_t *cp)
  28 {
  29         free(cp->cache);
  30         cp->cache = NULL;
  31         cp->size = 0;
  32 }
  33 void FAST_FUNC clear_username_cache(void)
  34 {
  35         clear_cache(&username);
  36         clear_cache(&groupname);
  37 }
  38
  39 #if 0 /* more generic, but we don't need that yet */
  40 /* Returns -N-1 if not found. */
  41 /* cp->cache[N] is allocated and must be filled in this case */
  42 static int get_cached(cache_t *cp, uid_t id)
  43 {
  44         int i;
  45         for (i = 0; i < cp->size; i++)
  46                 if (cp->cache[i].id == id)
  47                         return i;
  48         i = cp->size++;
  49         cp->cache = xrealloc_vector(cp->cache, 2, i);
  50         cp->cache[i++].id = id;
  51         return -i;
  52 }
  53 #endif
  54
  55 static char* get_cached(cache_t *cp, uid_t id,
  56                         char* FAST_FUNC x2x_utoa(uid_t id))
  57 {
  58         int i;
  59         for (i = 0; i < cp->size; i++)
  60                 if (cp->cache[i].id == id)
  61                         return cp->cache[i].name;
  62         i = cp->size++;
  63         cp->cache = xrealloc_vector(cp->cache, 2, i);
  64         cp->cache[i].id = id;
  65         /* Never fails. Generates numeric string if name isn't found */
  66         safe_strncpy(cp->cache[i].name, x2x_utoa(id), sizeof(cp->cache[i].name));
  67         return cp->cache[i].name;
  68 }
  69 const char* FAST_FUNC get_cached_username(uid_t uid)
  70 {
  71         return get_cached(&username, uid, uid2uname_utoa);
  72 }
  73 const char* FAST_FUNC get_cached_groupname(gid_t gid)
  74 {
  75         return get_cached(&groupname, gid, gid2group_utoa);
  76 }
  77
  78
  79 #define PROCPS_BUFSIZE 1024
  80
  81 static int read_to_buf(const char *filename, void *buf)
  82 {
  83         int fd;
  84         /* open_read_close() would do two reads, checking for EOF.
  85          * When you have 10000 /proc/$NUM/stat to read, it isn't desirable */
  86         ssize_t ret = -1;
  87         fd = open(filename, O_RDONLY);
  88         if (fd >= 0) {
  89                 ret = read(fd, buf, PROCPS_BUFSIZE-1);
  90                 close(fd);
  91         }
  92         ((char *)buf)[ret > 0 ? ret : 0] = '\0';
  93         return ret;
  94 }
  95
  96 static procps_status_t* FAST_FUNC alloc_procps_scan(void)
  97 {
  98         unsigned n = getpagesize();
  99         procps_status_t* sp = xzalloc(sizeof(procps_status_t));
 100         sp->dir = xopendir("/proc");
 101         while (1) {
 102                 n >>= 1;
 103                 if (!n) break;
 104                 sp->shift_pages_to_bytes++;
 105         }
 106         sp->shift_pages_to_kb = sp->shift_pages_to_bytes - 10;
 107         return sp;
 108 }
 109
 110 void FAST_FUNC free_procps_scan(procps_status_t* sp)
 111 {
 112         closedir(sp->dir);
 113 #if ENABLE_FEATURE_SHOW_THREADS
 114         if (sp->task_dir)
 115                 closedir(sp->task_dir);
 116 #endif
 117         free(sp->argv0);
 118         free(sp->exe);
 119         IF_SELINUX(free(sp->context);)
 120         free(sp);
 121 }
 122
 123 #if ENABLE_FEATURE_TOPMEM || ENABLE_PMAP
 124 static unsigned long fast_strtoul_16(char **endptr)
 125 {
 126         unsigned char c;
 127         char *str = *endptr;
 128         unsigned long n = 0;
 129
 130         while ((c = *str++) != ' ') {
 131                 c = ((c|0x20) - '0');
 132                 if (c > 9)
 133                         // c = c + '0' - 'a' + 10:
 134                         c = c - ('a' - '0' - 10);
 135                 n = n*16 + c;
 136         }
 137         *endptr = str; /* We skip trailing space! */
 138         return n;
 139 }
 140 #endif
 141
 142 #if ENABLE_FEATURE_FAST_TOP || ENABLE_FEATURE_TOPMEM || ENABLE_PMAP
 143 /* We cut a lot of corners here for speed */
 144 static unsigned long fast_strtoul_10(char **endptr)
 145 {
 146         char c;
 147         char *str = *endptr;
 148         unsigned long n = *str - '0';
 149
 150         while ((c = *++str) != ' ')
 151                 n = n*10 + (c - '0');
 152
 153         *endptr = str + 1; /* We skip trailing space! */
 154         return n;
 155 }
 156
 157 # if ENABLE_FEATURE_FAST_TOP
 158 static long fast_strtol_10(char **endptr)
 159 {
 160         if (**endptr != '-')
 161                 return fast_strtoul_10(endptr);
 162
 163         (*endptr)++;
 164         return - (long)fast_strtoul_10(endptr);
 165 }
 166 # endif
 167
 168 static char *skip_fields(char *str, int count)
 169 {
 170         do {
 171                 while (*str++ != ' ')
 172                         continue;
 173                 /* we found a space char, str points after it */
 174         } while (--count);
 175         return str;
 176 }
 177 #endif
 178
 179 #if ENABLE_FEATURE_TOPMEM || ENABLE_PMAP
 180 int FAST_FUNC procps_read_smaps(pid_t pid, struct smaprec *total,
 181                       void (*cb)(struct smaprec *, void *), void *data)
 182 {
 183         FILE *file;
 184         struct smaprec currec;
 185         char filename[sizeof("/proc/%u/smaps") + sizeof(int)*3];
 186         char buf[PROCPS_BUFSIZE];
 187 #if !ENABLE_PMAP
 188         void (*cb)(struct smaprec *, void *) = NULL;
 189         void *data = NULL;
 190 #endif
 191
 192         sprintf(filename, "/proc/%u/smaps", (int)pid);
 193
 194         file = fopen_for_read(filename);
 195         if (!file)
 196                 return 1;
 197
 198         memset(&currec, 0, sizeof(currec));
 199         while (fgets(buf, PROCPS_BUFSIZE, file)) {
 200                 // Each mapping datum has this form:
 201                 // f7d29000-f7d39000 rw-s ADR M:m OFS FILE
 202                 // Size:                nnn kB
 203                 // Rss:                 nnn kB
 204                 // .....
 205
 206                 char *tp = buf, *p;
 207
 208 #define SCAN(S, X) \
 209                 if (strncmp(tp, S, sizeof(S)-1) == 0) {              \
 210                         tp = skip_whitespace(tp + sizeof(S)-1);      \
 211                         total->X += currec.X = fast_strtoul_10(&tp); \
 212                         continue;                                    \
 213                 }
 214                 if (cb) {
 215                         SCAN("Pss:"  , smap_pss     );
 216                         SCAN("Swap:" , smap_swap    );
 217                 }
 218                 SCAN("Private_Dirty:", private_dirty);
 219                 SCAN("Private_Clean:", private_clean);
 220                 SCAN("Shared_Dirty:" , shared_dirty );
 221                 SCAN("Shared_Clean:" , shared_clean );
 222 #undef SCAN
 223                 tp = strchr(buf, '-');
 224                 if (tp) {
 225                         // We reached next mapping - the line of this form:
 226                         // f7d29000-f7d39000 rw-s ADR M:m OFS FILE
 227
 228                         if (cb) {
 229                                 /* If we have a previous record, there's nothing more
 230                                  * for it, call the callback and clear currec
 231                                  */
 232                                 if (currec.smap_size)
 233                                         cb(&currec, data);
 234                                 free(currec.smap_name);
 235                         }
 236                         memset(&currec, 0, sizeof(currec));
 237
 238                         *tp = ' ';
 239                         tp = buf;
 240                         currec.smap_start = fast_strtoul_16(&tp);
 241                         currec.smap_size = (fast_strtoul_16(&tp) - currec.smap_start) >> 10;
 242
 243                         strncpy(currec.smap_mode, tp, sizeof(currec.smap_mode)-1);
 244
 245                         // skipping "rw-s ADR M:m OFS "
 246                         tp = skip_whitespace(skip_fields(tp, 4));
 247                         // filter out /dev/something (something != zero)
 248                         if (strncmp(tp, "/dev/", 5) != 0 || strcmp(tp, "/dev/zero\n") == 0) {
 249                                 if (currec.smap_mode[1] == 'w') {
 250                                         currec.mapped_rw = currec.smap_size;
 251                                         total->mapped_rw += currec.smap_size;
 252                                 } else if (currec.smap_mode[1] == '-') {
 253                                         currec.mapped_ro = currec.smap_size;
 254                                         total->mapped_ro += currec.smap_size;
 255                                 }
 256                         }
 257
 258                         if (strcmp(tp, "[stack]\n") == 0)
 259                                 total->stack += currec.smap_size;
 260                         if (cb) {
 261                                 p = skip_non_whitespace(tp);
 262                                 if (p == tp) {
 263                                         currec.smap_name = xstrdup("  [ anon ]");
 264                                 } else {
 265                                         *p = '\0';
 266                                         currec.smap_name = xstrdup(tp);
 267                                 }
 268                         }
 269                         total->smap_size += currec.smap_size;
 270                 }
 271         }
 272         fclose(file);
 273
 274         if (cb) {
 275                 if (currec.smap_size)
 276                         cb(&currec, data);
 277                 free(currec.smap_name);
 278         }
 279
 280         return 0;
 281 }
 282 #endif
 283
 284 void BUG_comm_size(void);
 285 procps_status_t* FAST_FUNC procps_scan(procps_status_t* sp, int flags)
 286 {
 287         struct dirent *entry;
 288         char buf[PROCPS_BUFSIZE];
 289         char filename[sizeof("/proc//cmdline") + sizeof(int)*3];
 290         char *filename_tail;
 291         long tasknice;
 292         unsigned pid;
 293         int n;
 294         struct stat sb;
 295
 296         if (!sp)
 297                 sp = alloc_procps_scan();
 298
 299         for (;;) {
 300 #if ENABLE_FEATURE_SHOW_THREADS
 301                 if ((flags & PSSCAN_TASKS) && sp->task_dir) {
 302                         entry = readdir(sp->task_dir);
 303                         if (entry)
 304                                 goto got_entry;
 305                         closedir(sp->task_dir);
 306                         sp->task_dir = NULL;
 307                         sp->main_thread_pid = 0;
 308                 }
 309 #endif
 310                 entry = readdir(sp->dir);
 311                 if (entry == NULL) {
 312                         free_procps_scan(sp);
 313                         return NULL;
 314                 }
 315  IF_FEATURE_SHOW_THREADS(got_entry:)
 316                 pid = bb_strtou(entry->d_name, NULL, 10);
 317                 if (errno)
 318                         continue;
 319 #if ENABLE_FEATURE_SHOW_THREADS
 320                 if ((flags & PSSCAN_TASKS) && !sp->task_dir) {
 321                         /* We found another /proc/PID. Do not use it,
 322                          * there will be /proc/PID/task/PID (same PID!),
 323                          * so just go ahead and dive into /proc/PID/task. */
 324                         char task_dir[sizeof("/proc/%u/task") + sizeof(int)*3];
 325                         sprintf(task_dir, "/proc/%u/task", pid);
 326                         sp->task_dir = xopendir(task_dir);
 327                         sp->main_thread_pid = pid;
 328                         continue;
 329                 }
 330 #endif
 331
 332                 /* After this point we can:
 333                  * "break": stop parsing, return the data
 334                  * "continue": try next /proc/XXX
 335                  */
 336
 337                 memset(&sp->vsz, 0, sizeof(*sp) - offsetof(procps_status_t, vsz));
 338
 339                 sp->pid = pid;
 340                 if (!(flags & ~PSSCAN_PID))
 341                         break; /* we needed only pid, we got it */
 342
 343 #if ENABLE_SELINUX
 344                 if (flags & PSSCAN_CONTEXT) {
 345                         if (getpidcon(sp->pid, &sp->context) < 0)
 346                                 sp->context = NULL;
 347                 }
 348 #endif
 349
 350                 filename_tail = filename + sprintf(filename, "/proc/%u/", pid);
 351
 352                 if (flags & PSSCAN_UIDGID) {
 353                         if (stat(filename, &sb))
 354                                 continue; /* process probably exited */
 355                         /* Effective UID/GID, not real */
 356                         sp->uid = sb.st_uid;
 357                         sp->gid = sb.st_gid;
 358                 }
 359
 360                 /* These are all retrieved from proc/NN/stat in one go: */
 361                 if (flags & (PSSCAN_PPID | PSSCAN_PGID | PSSCAN_SID
 362                         | PSSCAN_COMM | PSSCAN_STATE
 363                         | PSSCAN_VSZ | PSSCAN_RSS
 364                         | PSSCAN_STIME | PSSCAN_UTIME | PSSCAN_START_TIME
 365                         | PSSCAN_TTY | PSSCAN_NICE
 366                         | PSSCAN_CPU)
 367                 ) {
 368                         char *cp, *comm1;
 369                         int tty;
 370 #if !ENABLE_FEATURE_FAST_TOP
 371                         unsigned long vsz, rss;
 372 #endif
 373                         /* see proc(5) for some details on this */
 374                         strcpy(filename_tail, "stat");
 375                         n = read_to_buf(filename, buf);
 376                         if (n < 0)
 377                                 continue; /* process probably exited */
 378                         cp = strrchr(buf, ')'); /* split into "PID (cmd" and "<rest>" */
 379                         /*if (!cp || cp[1] != ' ')
 380                                 continue;*/
 381                         cp[0] = '\0';
 382                         if (sizeof(sp->comm) < 16)
 383                                 BUG_comm_size();
 384                         comm1 = strchr(buf, '(');
 385                         /*if (comm1)*/
 386                                 safe_strncpy(sp->comm, comm1 + 1, sizeof(sp->comm));
 387
 388 #if !ENABLE_FEATURE_FAST_TOP
 389                         n = sscanf(cp+2,
 390                                 "%c %u "               /* state, ppid */
 391                                 "%u %u %d %*s "        /* pgid, sid, tty, tpgid */
 392                                 "%*s %*s %*s %*s %*s " /* flags, min_flt, cmin_flt, maj_flt, cmaj_flt */
 393                                 "%lu %lu "             /* utime, stime */
 394                                 "%*s %*s %*s "         /* cutime, cstime, priority */
 395                                 "%ld "                 /* nice */
 396                                 "%*s %*s "             /* timeout, it_real_value */
 397                                 "%lu "                 /* start_time */
 398                                 "%lu "                 /* vsize */
 399                                 "%lu "                 /* rss */
 400 # if ENABLE_FEATURE_TOP_SMP_PROCESS
 401                                 "%*s %*s %*s %*s %*s %*s " /*rss_rlim, start_code, end_code, start_stack, kstk_esp, kstk_eip */
 402                                 "%*s %*s %*s %*s "         /*signal, blocked, sigignore, sigcatch */
 403                                 "%*s %*s %*s %*s "         /*wchan, nswap, cnswap, exit_signal */
 404                                 "%d"                       /*cpu last seen on*/
 405 # endif
 406                                 ,
 407                                 sp->state, &sp->ppid,
 408                                 &sp->pgid, &sp->sid, &tty,
 409                                 &sp->utime, &sp->stime,
 410                                 &tasknice,
 411                                 &sp->start_time,
 412                                 &vsz,
 413                                 &rss
 414 # if ENABLE_FEATURE_TOP_SMP_PROCESS
 415                                 , &sp->last_seen_on_cpu
 416 # endif
 417                                 );
 418
 419                         if (n < 11)
 420                                 continue; /* bogus data, get next /proc/XXX */
 421 # if ENABLE_FEATURE_TOP_SMP_PROCESS
 422                         if (n < 11+15)
 423                                 sp->last_seen_on_cpu = 0;
 424 # endif
 425
 426                         /* vsz is in bytes and we want kb */
 427                         sp->vsz = vsz >> 10;
 428                         /* vsz is in bytes but rss is in *PAGES*! Can you believe that? */
 429                         sp->rss = rss << sp->shift_pages_to_kb;
 430                         sp->tty_major = (tty >> 8) & 0xfff;
 431                         sp->tty_minor = (tty & 0xff) | ((tty >> 12) & 0xfff00);
 432 #else
 433 /* This costs ~100 bytes more but makes top faster by 20%
 434  * If you run 10000 processes, this may be important for you */
 435                         sp->state[0] = cp[2];
 436                         cp += 4;
 437                         sp->ppid = fast_strtoul_10(&cp);
 438                         sp->pgid = fast_strtoul_10(&cp);
 439                         sp->sid = fast_strtoul_10(&cp);
 440                         tty = fast_strtoul_10(&cp);
 441                         sp->tty_major = (tty >> 8) & 0xfff;
 442                         sp->tty_minor = (tty & 0xff) | ((tty >> 12) & 0xfff00);
 443                         cp = skip_fields(cp, 6); /* tpgid, flags, min_flt, cmin_flt, maj_flt, cmaj_flt */
 444                         sp->utime = fast_strtoul_10(&cp);
 445                         sp->stime = fast_strtoul_10(&cp);
 446                         cp = skip_fields(cp, 3); /* cutime, cstime, priority */
 447                         tasknice = fast_strtol_10(&cp);
 448                         cp = skip_fields(cp, 2); /* timeout, it_real_value */
 449                         sp->start_time = fast_strtoul_10(&cp);
 450                         /* vsz is in bytes and we want kb */
 451                         sp->vsz = fast_strtoul_10(&cp) >> 10;
 452                         /* vsz is in bytes but rss is in *PAGES*! Can you believe that? */
 453                         sp->rss = fast_strtoul_10(&cp) << sp->shift_pages_to_kb;
 454 # if ENABLE_FEATURE_TOP_SMP_PROCESS
 455                         /* (6): rss_rlim, start_code, end_code, start_stack, kstk_esp, kstk_eip */
 456                         /* (4): signal, blocked, sigignore, sigcatch */
 457                         /* (4): wchan, nswap, cnswap, exit_signal */
 458                         cp = skip_fields(cp, 14);
 459 //FIXME: is it safe to assume this field exists?
 460                         sp->last_seen_on_cpu = fast_strtoul_10(&cp);
 461 # endif
 462 #endif /* FEATURE_FAST_TOP */
 463
 464 #if ENABLE_FEATURE_PS_ADDITIONAL_COLUMNS
 465                         sp->niceness = tasknice;
 466 #endif
 467
 468                         if (sp->vsz == 0 && sp->state[0] != 'Z')
 469                                 sp->state[1] = 'W';
 470                         else
 471                                 sp->state[1] = ' ';
 472                         if (tasknice < 0)
 473                                 sp->state[2] = '<';
 474                         else if (tasknice) /* > 0 */
 475                                 sp->state[2] = 'N';
 476                         else
 477                                 sp->state[2] = ' ';
 478                 }
 479
 480 #if ENABLE_FEATURE_TOPMEM
 481                 if (flags & PSSCAN_SMAPS)
 482                         procps_read_smaps(pid, &sp->smaps, NULL, NULL);
 483 #endif /* TOPMEM */
 484 #if ENABLE_FEATURE_PS_ADDITIONAL_COLUMNS
 485                 if (flags & PSSCAN_RUIDGID) {
 486                         FILE *file;
 487
 488                         strcpy(filename_tail, "status");
 489                         file = fopen_for_read(filename);
 490                         if (file) {
 491                                 while (fgets(buf, sizeof(buf), file)) {
 492                                         char *tp;
 493 #define SCAN_TWO(str, name, statement) \
 494         if (strncmp(buf, str, sizeof(str)-1) == 0) { \
 495                 tp = skip_whitespace(buf + sizeof(str)-1); \
 496                 sscanf(tp, "%u", &sp->name); \
 497                 statement; \
 498         }
 499                                         SCAN_TWO("Uid:", ruid, continue);
 500                                         SCAN_TWO("Gid:", rgid, break);
 501 #undef SCAN_TWO
 502                                 }
 503                                 fclose(file);
 504                         }
 505                 }
 506 #endif /* PS_ADDITIONAL_COLUMNS */
 507                 if (flags & PSSCAN_EXE) {
 508                         strcpy(filename_tail, "exe");
 509                         free(sp->exe);
 510                         sp->exe = xmalloc_readlink(filename);
 511                 }
 512                 /* Note: if /proc/PID/cmdline is empty,
 513                  * code below "breaks". Therefore it must be
 514                  * the last code to parse /proc/PID/xxx data
 515                  * (we used to have /proc/PID/exe parsing after it
 516                  * and were getting stale sp->exe).
 517                  */
 518 #if 0 /* PSSCAN_CMD is not used */
 519                 if (flags & (PSSCAN_CMD|PSSCAN_ARGV0)) {
 520                         free(sp->argv0);
 521                         sp->argv0 = NULL;
 522                         free(sp->cmd);
 523                         sp->cmd = NULL;
 524                         strcpy(filename_tail, "cmdline");
 525                         /* TODO: to get rid of size limits, read into malloc buf,
 526                          * then realloc it down to real size. */
 527                         n = read_to_buf(filename, buf);
 528                         if (n <= 0)
 529                                 break;
 530                         if (flags & PSSCAN_ARGV0)
 531                                 sp->argv0 = xstrdup(buf);
 532                         if (flags & PSSCAN_CMD) {
 533                                 do {
 534                                         n--;
 535                                         if ((unsigned char)(buf[n]) < ' ')
 536                                                 buf[n] = ' ';
 537                                 } while (n);
 538                                 sp->cmd = xstrdup(buf);
 539                         }
 540                 }
 541 #else
 542                 if (flags & (PSSCAN_ARGV0|PSSCAN_ARGVN)) {
 543                         free(sp->argv0);
 544                         sp->argv0 = NULL;
 545                         strcpy(filename_tail, "cmdline");
 546                         n = read_to_buf(filename, buf);
 547                         if (n <= 0)
 548                                 break;
 549                         if (flags & PSSCAN_ARGVN) {
 550                                 sp->argv_len = n;
 551                                 sp->argv0 = xmalloc(n + 1);
 552                                 memcpy(sp->argv0, buf, n + 1);
 553                                 /* sp->argv0[n] = '\0'; - buf has it */
 554                         } else {
 555                                 sp->argv_len = 0;
 556                                 sp->argv0 = xstrdup(buf);
 557                         }
 558                 }
 559 #endif
 560                 break;
 561         } /* for (;;) */
 562
 563         return sp;
 564 }
 565
 566 void FAST_FUNC read_cmdline(char *buf, int col, unsigned pid, const char *comm)
 567 {
 568         int sz;
 569         char filename[sizeof("/proc/%u/cmdline") + sizeof(int)*3];
 570
 571         sprintf(filename, "/proc/%u/cmdline", pid);
 572         sz = open_read_close(filename, buf, col - 1);
 573         if (sz > 0) {
 574                 const char *base;
 575                 int comm_len;
 576
 577                 buf[sz] = '\0';
 578                 while (--sz >= 0 && buf[sz] == '\0')
 579                         continue;
 580                 base = bb_basename(buf); /* before we replace argv0's NUL with space */
 581                 while (sz >= 0) {
 582                         if ((unsigned char)(buf[sz]) < ' ')
 583                                 buf[sz] = ' ';
 584                         sz--;
 585                 }
 586
 587                 /* If comm differs from argv0, prepend "{comm} ".
 588                  * It allows to see thread names set by prctl(PR_SET_NAME).
 589                  */
 590                 if (base[0] == '-') /* "-sh" (login shell)? */
 591                         base++;
 592                 comm_len = strlen(comm);
 593                 /* Why compare up to comm_len, not COMM_LEN-1?
 594                  * Well, some processes rewrite argv, and use _spaces_ there
 595                  * while rewriting. (KDE is observed to do it).
 596                  * I prefer to still treat argv0 "process foo bar"
 597                  * as 'equal' to comm "process".
 598                  */
 599                 if (strncmp(base, comm, comm_len) != 0) {
 600                         comm_len += 3;
 601                         if (col > comm_len)
 602                                 memmove(buf + comm_len, buf, col - comm_len);
 603                         snprintf(buf, col, "{%s}", comm);
 604                         if (col <= comm_len)
 605                                 return;
 606                         buf[comm_len - 1] = ' ';
 607                         buf[col - 1] = '\0';
 608                 }
 609
 610         } else {
 611                 snprintf(buf, col, "[%s]", comm);
 612         }
 613 }
 614
 615 /* from kernel:
 616         //             pid comm S ppid pgid sid tty_nr tty_pgrp flg
 617         sprintf(buffer,"%d (%s) %c %d  %d   %d  %d     %d       %lu %lu \
 618 %lu %lu %lu %lu %lu %ld %ld %ld %ld %d 0 %llu %lu %ld %lu %lu %lu %lu %lu \
 619 %lu %lu %lu %lu %lu %lu %lu %lu %d %d %lu %lu %llu\n",
 620                 task->pid,
 621                 tcomm,
 622                 state,
 623                 ppid,
 624                 pgid,
 625                 sid,
 626                 tty_nr,
 627                 tty_pgrp,
 628                 task->flags,
 629                 min_flt,
 630                 cmin_flt,
 631                 maj_flt,
 632                 cmaj_flt,
 633                 cputime_to_clock_t(utime),
 634                 cputime_to_clock_t(stime),
 635                 cputime_to_clock_t(cutime),
 636                 cputime_to_clock_t(cstime),
 637                 priority,
 638                 nice,
 639                 num_threads,
 640                 // 0,
 641                 start_time,
 642                 vsize,
 643                 mm ? get_mm_rss(mm) : 0,
 644                 rsslim,
 645                 mm ? mm->start_code : 0,
 646                 mm ? mm->end_code : 0,
 647                 mm ? mm->start_stack : 0,
 648                 esp,
 649                 eip,
 650 the rest is some obsolete cruft
 651 */