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