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 tarball for details.
  10  */
  11
  12 #include "libbb.h"
  13
  14
  15 typedef struct unsigned_to_name_map_t {
  16         unsigned id;
  17         char name[USERNAME_MAX_SIZE];
  18 } unsigned_to_name_map_t;
  19
  20 typedef struct cache_t {
  21         unsigned_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 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, unsigned 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(cp->cache, cp->size * sizeof(*cp->cache));
  50         cp->cache[i++].id = id;
  51         return -i;
  52 }
  53 #endif
  54
  55 typedef char* ug_func(char *name, long uid, int bufsize);
  56 static char* get_cached(cache_t *cp, unsigned id, ug_func* fp)
  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(cp->cache, cp->size * sizeof(*cp->cache));
  64         cp->cache[i].id = id;
  65         fp(cp->cache[i].name, id, sizeof(cp->cache[i].name));
  66         return cp->cache[i].name;
  67 }
  68 const char* get_cached_username(uid_t uid)
  69 {
  70         return get_cached(&username, uid, bb_getpwuid);
  71 }
  72 const char* get_cached_groupname(gid_t gid)
  73 {
  74         return get_cached(&groupname, gid, bb_getgrgid);
  75 }
  76
  77
  78 #define PROCPS_BUFSIZE 1024
  79
  80 static int read_to_buf(const char *filename, void *buf)
  81 {
  82         int fd;
  83         /* open_read_close() would do two reads, checking for EOF.
  84          * When you have 10000 /proc/$NUM/stat to read, it isn't desirable */
  85         ssize_t ret = -1;
  86         fd = open(filename, O_RDONLY);
  87         if (fd >= 0) {
  88                 ret = read(fd, buf, PROCPS_BUFSIZE-1);
  89                 close(fd);
  90         }
  91         ((char *)buf)[ret > 0 ? ret : 0] = '\0';
  92         return ret;
  93 }
  94
  95 procps_status_t* alloc_procps_scan(int flags)
  96 {
  97         procps_status_t* sp = xzalloc(sizeof(procps_status_t));
  98         sp->dir = xopendir("/proc");
  99         return sp;
 100 }
 101
 102 void free_procps_scan(procps_status_t* sp)
 103 {
 104         closedir(sp->dir);
 105         free(sp->cmd);
 106         USE_SELINUX(free(sp->context);)
 107         free(sp);
 108 }
 109
 110 #if ENABLE_FEATURE_FAST_TOP
 111 /* We cut a lot of corners here for speed */
 112 static unsigned long fast_strtoul_10(char *str, char **endptr)
 113 {
 114         char c;
 115         unsigned long n = *str - '0';
 116
 117         while ((c = *++str) != ' ')
 118                 n = n*10 + (c - '0');
 119
 120         *endptr = str + 1; /* We skip trailing space! */
 121         return n;
 122 }
 123 static char *skip_fields(char *str, int count)
 124 {
 125         do {
 126                 str = skip_non_whitespace(str); str++;
 127         } while (--count);
 128         return str;
 129 }
 130 #endif
 131
 132 void BUG_comm_size(void);
 133 procps_status_t* procps_scan(procps_status_t* sp, int flags)
 134 {
 135         struct dirent *entry;
 136         char buf[PROCPS_BUFSIZE];
 137         char filename[sizeof("/proc//cmdline") + sizeof(int)*3];
 138         char *filename_tail;
 139         long tasknice;
 140         unsigned pid;
 141         int n;
 142         struct stat sb;
 143
 144         if (!sp)
 145                 sp = alloc_procps_scan(flags);
 146
 147         for (;;) {
 148                 entry = readdir(sp->dir);
 149                 if (entry == NULL) {
 150                         free_procps_scan(sp);
 151                         return NULL;
 152                 }
 153                 pid = bb_strtou(entry->d_name, NULL, 10);
 154                 if (errno)
 155                         continue;
 156
 157                 /* After this point we have to break, not continue
 158                  * ("continue" would mean that current /proc/NNN
 159                  * is not a valid process info) */
 160
 161                 memset(&sp->vsz, 0, sizeof(*sp) - offsetof(procps_status_t, vsz));
 162
 163                 sp->pid = pid;
 164                 if (!(flags & ~PSSCAN_PID)) break;
 165
 166 #if ENABLE_SELINUX
 167                 if (flags & PSSCAN_CONTEXT) {
 168                         if (getpidcon(sp->pid, &sp->context) < 0)
 169                                 sp->context = NULL;
 170                 }
 171 #endif
 172
 173                 filename_tail = filename + sprintf(filename, "/proc/%d", pid);
 174
 175                 if (flags & PSSCAN_UIDGID) {
 176                         if (stat(filename, &sb))
 177                                 break;
 178                         /* Need comment - is this effective or real UID/GID? */
 179                         sp->uid = sb.st_uid;
 180                         sp->gid = sb.st_gid;
 181                 }
 182
 183                 if (flags & PSSCAN_STAT) {
 184                         char *cp;
 185 #if !ENABLE_FEATURE_FAST_TOP
 186                         unsigned long vsz, rss;
 187 #endif
 188                         int tty;
 189
 190                         /* see proc(5) for some details on this */
 191                         strcpy(filename_tail, "/stat");
 192                         n = read_to_buf(filename, buf);
 193                         if (n < 0)
 194                                 break;
 195                         cp = strrchr(buf, ')'); /* split into "PID (cmd" and "<rest>" */
 196                         if (!cp || cp[1] != ' ')
 197                                 break;
 198                         cp[0] = '\0';
 199                         if (sizeof(sp->comm) < 16)
 200                                 BUG_comm_size();
 201                         sscanf(buf, "%*s (%15c", sp->comm);
 202
 203 #if !ENABLE_FEATURE_FAST_TOP
 204                         n = sscanf(cp+2,
 205                                 "%c %u "               /* state, ppid */
 206                                 "%u %u %d %*s "        /* pgid, sid, tty, tpgid */
 207                                 "%*s %*s %*s %*s %*s " /* flags, min_flt, cmin_flt, maj_flt, cmaj_flt */
 208                                 "%lu %lu "             /* utime, stime */
 209                                 "%*s %*s %*s "         /* cutime, cstime, priority */
 210                                 "%ld "                 /* nice */
 211                                 "%*s %*s %*s "         /* timeout, it_real_value, start_time */
 212                                 "%lu "                 /* vsize */
 213                                 "%lu "                 /* rss */
 214                         /*      "%lu %lu %lu %lu %lu %lu " rss_rlim, start_code, end_code, start_stack, kstk_esp, kstk_eip */
 215                         /*      "%u %u %u %u "         signal, blocked, sigignore, sigcatch */
 216                         /*      "%lu %lu %lu"          wchan, nswap, cnswap */
 217                                 ,
 218                                 sp->state, &sp->ppid,
 219                                 &sp->pgid, &sp->sid, &tty,
 220                                 &sp->utime, &sp->stime,
 221                                 &tasknice,
 222                                 &vsz,
 223                                 &rss);
 224                         if (n != 10)
 225                                 break;
 226                         sp->vsz = vsz >> 10; /* vsize is in bytes and we want kb */
 227                         sp->rss = rss >> 10;
 228                         sp->tty_major = (tty >> 8) & 0xfff;
 229                         sp->tty_minor = (tty & 0xff) | ((tty >> 12) & 0xfff00);
 230 #else
 231 /* This costs ~100 bytes more but makes top faster by 20%
 232  * If you run 10000 processes, this may be important for you */
 233                         sp->state[0] = cp[2];
 234                         sp->ppid = fast_strtoul_10(cp + 4, &cp);
 235                         sp->pgid = fast_strtoul_10(cp, &cp);
 236                         sp->sid = fast_strtoul_10(cp, &cp);
 237                         tty = fast_strtoul_10(cp, &cp);
 238                         sp->tty_major = (tty >> 8) & 0xfff;
 239                         sp->tty_minor = (tty & 0xff) | ((tty >> 12) & 0xfff00);
 240                         cp = skip_fields(cp, 6); /* tpgid, flags, min_flt, cmin_flt, maj_flt, cmaj_flt */
 241                         sp->utime = fast_strtoul_10(cp, &cp);
 242                         sp->stime = fast_strtoul_10(cp, &cp);
 243                         cp = skip_fields(cp, 3); /* cutime, cstime, priority */
 244                         tasknice = fast_strtoul_10(cp, &cp);
 245                         cp = skip_fields(cp, 3); /* timeout, it_real_value, start_time */
 246                         sp->vsz = fast_strtoul_10(cp, &cp) >> 10; /* vsize is in bytes and we want kb */
 247                         sp->rss = fast_strtoul_10(cp, &cp) >> 10;
 248 #endif
 249
 250                         if (sp->vsz == 0 && sp->state[0] != 'Z')
 251                                 sp->state[1] = 'W';
 252                         else
 253                                 sp->state[1] = ' ';
 254                         if (tasknice < 0)
 255                                 sp->state[2] = '<';
 256                         else if (tasknice) /* > 0 */
 257                                 sp->state[2] = 'N';
 258                         else
 259                                 sp->state[2] = ' ';
 260
 261                 }
 262
 263                 if (flags & PSSCAN_CMD) {
 264                         free(sp->cmd);
 265                         sp->cmd = NULL;
 266                         strcpy(filename_tail, "/cmdline");
 267                         n = read_to_buf(filename, buf);
 268                         if (n <= 0)
 269                                 break;
 270                         if (buf[n-1] == '\n') {
 271                                 if (!--n)
 272                                         break;
 273                                 buf[n] = '\0';
 274                         }
 275                         do {
 276                                 n--;
 277                                 if ((unsigned char)(buf[n]) < ' ')
 278                                         buf[n] = ' ';
 279                         } while (n);
 280                         sp->cmd = xstrdup(buf);
 281                 }
 282                 break;
 283         }
 284         return sp;
 285 }
 286 /* from kernel:
 287         //             pid comm S ppid pgid sid tty_nr tty_pgrp flg
 288         sprintf(buffer,"%d (%s) %c %d  %d   %d  %d     %d       %lu %lu \
 289 %lu %lu %lu %lu %lu %ld %ld %ld %ld %d 0 %llu %lu %ld %lu %lu %lu %lu %lu \
 290 %lu %lu %lu %lu %lu %lu %lu %lu %d %d %lu %lu %llu\n",
 291                 task->pid,
 292                 tcomm,
 293                 state,
 294                 ppid,
 295                 pgid,
 296                 sid,
 297                 tty_nr,
 298                 tty_pgrp,
 299                 task->flags,
 300                 min_flt,
 301                 cmin_flt,
 302                 maj_flt,
 303                 cmaj_flt,
 304                 cputime_to_clock_t(utime),
 305                 cputime_to_clock_t(stime),
 306                 cputime_to_clock_t(cutime),
 307                 cputime_to_clock_t(cstime),
 308                 priority,
 309                 nice,
 310                 num_threads,
 311                 // 0,
 312                 start_time,
 313                 vsize,
 314                 mm ? get_mm_rss(mm) : 0,
 315                 rsslim,
 316                 mm ? mm->start_code : 0,
 317                 mm ? mm->end_code : 0,
 318                 mm ? mm->start_stack : 0,
 319                 esp,
 320                 eip,
 321 the rest is some obsolete cruft
 322 */