procps/pstree.c

   1 /*
   2  * pstree.c - display process tree
   3  *
   4  * Copyright (C) 1993-2002 Werner Almesberger
   5  * Copyright (C) 2002-2009 Craig Small
   6  * Copyright (C) 2010 Lauri Kasanen
   7  *
   8  * Based on pstree (PSmisc) 22.13.
   9  *
  10  * Licensed under GPLv2, see file LICENSE in this source tree.
  11  */
  12
  13 //config:config PSTREE
  14 //config:       bool "pstree"
  15 //config:       default y
  16 //config:       help
  17 //config:         Display a tree of processes.
  18
  19 //applet:IF_PSTREE(APPLET(pstree, _BB_DIR_USR_BIN, _BB_SUID_DROP))
  20
  21 //kbuild:lib-$(CONFIG_PSTREE) += pstree.o
  22
  23 //usage:#define pstree_trivial_usage
  24 //usage:        "[-p] [PID|USER]"
  25 //usage:#define pstree_full_usage "\n\n"
  26 //usage:       "Display process tree, optionally start from USER or PID\n"
  27 //usage:     "\nOptions:"
  28 //usage:     "\n        -p      Show pids"
  29
  30 #include "libbb.h"
  31
  32 #define PROC_BASE "/proc"
  33
  34 #define OPT_PID  (1 << 0)
  35
  36 struct child;
  37
  38 typedef struct proc {
  39         char comm[COMM_LEN + 1];
  40 //      char flags; - unused, delete?
  41         pid_t pid;
  42         uid_t uid;
  43         struct child *children;
  44         struct proc *parent;
  45         struct proc *next;
  46 } PROC;
  47
  48 /* For flags above */
  49 //#define PFLAG_THREAD  0x01
  50
  51 typedef struct child {
  52         PROC *child;
  53         struct child *next;
  54 } CHILD;
  55
  56 #define empty_2  "  "
  57 #define branch_2 "|-"
  58 #define vert_2   "| "
  59 #define last_2   "`-"
  60 #define single_3 "---"
  61 #define first_3  "-+-"
  62
  63 struct globals {
  64         /* 0-based. IOW: the number of chars we printer on current line */
  65         unsigned cur_x;
  66         unsigned output_width;
  67
  68         /* The buffers will be dynamically increased in size as needed */
  69         unsigned capacity;
  70         unsigned *width;
  71         uint8_t *more;
  72
  73         PROC *list;
  74
  75         smallint dumped; /* used by dump_by_user */
  76 };
  77 #define G (*ptr_to_globals)
  78 #define INIT_G() do { \
  79         SET_PTR_TO_GLOBALS(xzalloc(sizeof(G))); \
  80 } while (0)
  81
  82
  83 /*
  84  * Allocates additional buffer space for width and more as needed.
  85  * The first call will allocate the first buffer.
  86  *
  87  * bufindex  the index that will be used after the call to this function.
  88  */
  89 static void ensure_buffer_capacity(int bufindex)
  90 {
  91         if (bufindex >= G.capacity) {
  92                 G.capacity += 0x100;
  93                 G.width = xrealloc(G.width, G.capacity * sizeof(G.width[0]));
  94                 G.more = xrealloc(G.more, G.capacity * sizeof(G.more[0]));
  95         }
  96 }
  97
  98 #if ENABLE_FEATURE_CLEAN_UP
  99 static void maybe_free_buffers(void)
 100 {
 101         free(G.width);
 102         free(G.more);
 103 }
 104 #else
 105 # define maybe_free_buffers() ((void)0)
 106 #endif
 107
 108 /* NB: this function is never called with "bad" chars
 109  * (control chars or chars >= 0x7f)
 110  */
 111 static void out_char(char c)
 112 {
 113         G.cur_x++;
 114         if (G.cur_x > G.output_width)
 115                 return;
 116         if (G.cur_x == G.output_width)
 117                 c = '+';
 118         putchar(c);
 119 }
 120
 121 /* NB: this function is never called with "bad" chars
 122  * (control chars or chars >= 0x7f)
 123  */
 124 static void out_string(const char *str)
 125 {
 126         while (*str)
 127                 out_char(*str++);
 128 }
 129
 130 static void out_newline(void)
 131 {
 132         putchar('\n');
 133         G.cur_x = 0;
 134 }
 135
 136 static PROC *find_proc(pid_t pid)
 137 {
 138         PROC *walk;
 139
 140         for (walk = G.list; walk; walk = walk->next)
 141                 if (walk->pid == pid)
 142                         break;
 143
 144         return walk;
 145 }
 146
 147 static PROC *new_proc(const char *comm, pid_t pid, uid_t uid)
 148 {
 149         PROC *new = xzalloc(sizeof(*new));
 150
 151         strcpy(new->comm, comm);
 152         new->pid = pid;
 153         new->uid = uid;
 154         new->next = G.list;
 155
 156         G.list = new;
 157         return G.list;
 158 }
 159
 160 static void add_child(PROC *parent, PROC *child)
 161 {
 162         CHILD *new, **walk;
 163         int cmp;
 164
 165         new = xmalloc(sizeof(*new));
 166
 167         new->child = child;
 168         for (walk = &parent->children; *walk; walk = &(*walk)->next) {
 169                 cmp = strcmp((*walk)->child->comm, child->comm);
 170                 if (cmp > 0)
 171                         break;
 172                 if (cmp == 0 && (*walk)->child->uid > child->uid)
 173                         break;
 174         }
 175         new->next = *walk;
 176         *walk = new;
 177 }
 178
 179 static void add_proc(const char *comm, pid_t pid, pid_t ppid,
 180                         uid_t uid /*, char isthread*/)
 181 {
 182         PROC *this, *parent;
 183
 184         this = find_proc(pid);
 185         if (!this)
 186                 this = new_proc(comm, pid, uid);
 187         else {
 188                 strcpy(this->comm, comm);
 189                 this->uid = uid;
 190         }
 191
 192         if (pid == ppid)
 193                 ppid = 0;
 194 //      if (isthread)
 195 //              this->flags |= PFLAG_THREAD;
 196
 197         parent = find_proc(ppid);
 198         if (!parent)
 199                 parent = new_proc("?", ppid, 0);
 200
 201         add_child(parent, this);
 202         this->parent = parent;
 203 }
 204
 205 static int tree_equal(const PROC *a, const PROC *b)
 206 {
 207         const CHILD *walk_a, *walk_b;
 208
 209         if (strcmp(a->comm, b->comm) != 0)
 210                 return 0;
 211         if ((option_mask32 /*& OPT_PID*/) && a->pid != b->pid)
 212                 return 0;
 213
 214         for (walk_a = a->children, walk_b = b->children;
 215           walk_a && walk_b;
 216           walk_a = walk_a->next, walk_b = walk_b->next
 217         ) {
 218                 if (!tree_equal(walk_a->child, walk_b->child))
 219                         return 0;
 220         }
 221
 222         return !(walk_a || walk_b);
 223 }
 224
 225 static int out_args(const char *mystr)
 226 {
 227         const char *here;
 228         int strcount = 0;
 229         char tmpstr[5];
 230
 231         for (here = mystr; *here; here++) {
 232                 if (*here == '\\') {
 233                         out_string("\\\\");
 234                         strcount += 2;
 235                 } else if (*here >= ' ' && *here < 0x7f) {
 236                         out_char(*here);
 237                         strcount++;
 238                 } else {
 239                         sprintf(tmpstr, "\\%03o", (unsigned char) *here);
 240                         out_string(tmpstr);
 241                         strcount += 4;
 242                 }
 243         }
 244
 245         return strcount;
 246 }
 247
 248 static void
 249 dump_tree(PROC *current, int level, int rep, int leaf, int last, int closing)
 250 {
 251         CHILD *walk, *next, **scan;
 252         int lvl, i, add, offset, count, comm_len, first;
 253         char tmp[sizeof(int)*3 + 4];
 254
 255         if (!current)
 256                 return;
 257
 258         if (!leaf) {
 259                 for (lvl = 0; lvl < level; lvl++) {
 260                         i = G.width[lvl] + 1;
 261                         while (--i >= 0)
 262                                 out_char(' ');
 263
 264                         if (lvl == level - 1) {
 265                                 if (last) {
 266                                         out_string(last_2);
 267                                 } else {
 268                                         out_string(branch_2);
 269                                 }
 270                         } else {
 271                                 if (G.more[lvl + 1]) {
 272                                         out_string(vert_2);
 273                                 } else {
 274                                         out_string(empty_2);
 275                                 }
 276                         }
 277                 }
 278         }
 279
 280         add = 0;
 281         if (rep > 1) {
 282                 add += sprintf(tmp, "%d*[", rep);
 283                 out_string(tmp);
 284         }
 285         comm_len = out_args(current->comm);
 286         if (option_mask32 /*& OPT_PID*/) {
 287                 comm_len += sprintf(tmp, "(%d)", (int)current->pid);
 288                 out_string(tmp);
 289         }
 290         offset = G.cur_x;
 291
 292         if (!current->children) {
 293                 while (closing--)
 294                         out_char(']');
 295                 out_newline();
 296         }
 297         ensure_buffer_capacity(level);
 298         G.more[level] = !last;
 299
 300         G.width[level] = comm_len + G.cur_x - offset + add;
 301         if (G.cur_x >= G.output_width) {
 302                 //out_string(first_3); - why? it won't print anything
 303                 //out_char('+');
 304                 out_newline();
 305                 return;
 306         }
 307
 308         first = 1;
 309         for (walk = current->children; walk; walk = next) {
 310                 count = 0;
 311                 next = walk->next;
 312                 scan = &walk->next;
 313                 while (*scan) {
 314                         if (!tree_equal(walk->child, (*scan)->child))
 315                                 scan = &(*scan)->next;
 316                         else {
 317                                 if (next == *scan)
 318                                         next = (*scan)->next;
 319                                 count++;
 320                                 *scan = (*scan)->next;
 321                         }
 322                 }
 323                 if (first) {
 324                         out_string(next ? first_3 : single_3);
 325                         first = 0;
 326                 }
 327
 328                 dump_tree(walk->child, level + 1, count + 1,
 329                                 walk == current->children, !next,
 330                                 closing + (count ? 1 : 0));
 331         }
 332 }
 333
 334 static void dump_by_user(PROC *current, uid_t uid)
 335 {
 336         const CHILD *walk;
 337
 338         if (!current)
 339                 return;
 340
 341         if (current->uid == uid) {
 342                 if (G.dumped)
 343                         putchar('\n');
 344                 dump_tree(current, 0, 1, 1, 1, 0);
 345                 G.dumped = 1;
 346                 return;
 347         }
 348         for (walk = current->children; walk; walk = walk->next)
 349                 dump_by_user(walk->child, uid);
 350 }
 351
 352 static void handle_thread(const char *comm, pid_t pid, pid_t ppid, uid_t uid)
 353 {
 354         char threadname[COMM_LEN + 2];
 355         sprintf(threadname, "{%.*s}", COMM_LEN - 2, comm);
 356         add_proc(threadname, pid, ppid, uid/*, 1*/);
 357 }
 358
 359 static void mread_proc(void)
 360 {
 361         procps_status_t *p = NULL;
 362         pid_t parent = 0;
 363         int flags = PSSCAN_COMM | PSSCAN_PID | PSSCAN_PPID | PSSCAN_UIDGID | PSSCAN_TASKS;
 364
 365         while ((p = procps_scan(p, flags)) != NULL) {
 366 #if ENABLE_FEATURE_SHOW_THREADS
 367                 if (p->pid != p->main_thread_pid)
 368                         handle_thread(p->comm, p->pid, parent, p->uid);
 369                 else
 370 #endif
 371                 {
 372                         add_proc(p->comm, p->pid, p->ppid, p->uid/*, 0*/);
 373                         parent = p->pid;
 374                 }
 375         }
 376 }
 377
 378 int pstree_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
 379 int pstree_main(int argc UNUSED_PARAM, char **argv)
 380 {
 381         pid_t pid = 1;
 382         long uid = 0;
 383
 384         INIT_G();
 385
 386         get_terminal_width_height(1, &G.output_width, NULL);
 387
 388         getopt32(argv, "p");
 389         argv += optind;
 390
 391         if (argv[0]) {
 392                 if (argv[1])
 393                         bb_show_usage();
 394                 if (argv[0][0] >= '0' && argv[0][0] <= '9') {
 395                         pid = xatoi(argv[0]);
 396                 } else {
 397                         uid = xuname2uid(argv[0]);
 398                 }
 399         }
 400
 401         mread_proc();
 402
 403         if (!uid)
 404                 dump_tree(find_proc(pid), 0, 1, 1, 1, 0);
 405         else {
 406                 dump_by_user(find_proc(1), uid);
 407                 if (!G.dumped) {
 408                         bb_error_msg_and_die("no processes found");
 409                 }
 410         }
 411
 412         maybe_free_buffers();
 413         return 0;
 414 }