source: MondoRescue/branches/3.3/mindi-busybox/procps/pstree.c@ 3621

/*
 * pstree.c - display process tree
 *
 * Copyright (C) 1993-2002 Werner Almesberger
 * Copyright (C) 2002-2009 Craig Small
 * Copyright (C) 2010 Lauri Kasanen
 *
 * Based on pstree (PSmisc) 22.13.
 *
 * Licensed under GPLv2, see file LICENSE in this source tree.
 */

//config:config PSTREE
//config:   bool "pstree"
//config:   default y
//config:   help
//config:     Display a tree of processes.

//applet:IF_PSTREE(APPLET(pstree, BB_DIR_USR_BIN, BB_SUID_DROP))

//kbuild:lib-$(CONFIG_PSTREE) += pstree.o

//usage:#define pstree_trivial_usage
//usage:    "[-p] [PID|USER]"
//usage:#define pstree_full_usage "\n\n"
//usage:       "Display process tree, optionally start from USER or PID\n"
//usage:     "\n    -p  Show pids"

#include "libbb.h"

#define PROC_BASE "/proc"

#define OPT_PID  (1 << 0)

struct child;

#ifdef ENABLE_FEATURE_SHOW_THREADS
/* For threads, we add {...} around the comm, so we need two extra bytes */
# define COMM_DISP_LEN (COMM_LEN + 2)
#else
# define COMM_DISP_LEN COMM_LEN
#endif

typedef struct proc {
    char comm[COMM_DISP_LEN + 1];
//  char flags; - unused, delete?
    pid_t pid;
    uid_t uid;
    struct child *children;
    struct proc *parent;
    struct proc *next;
} PROC;

/* For flags above */
//#define PFLAG_THREAD  0x01

typedef struct child {
    PROC *child;
    struct child *next;
} CHILD;

#define empty_2  "  "
#define branch_2 "|-"
#define vert_2   "| "
#define last_2   "`-"
#define single_3 "---"
#define first_3  "-+-"

struct globals {
    /* 0-based. IOW: the number of chars we printed on current line */
    unsigned cur_x;
    unsigned output_width;

    /* The buffers will be dynamically increased in size as needed */
    unsigned capacity;
    unsigned *width;
    uint8_t *more;

    PROC *list;

    smallint dumped; /* used by dump_by_user */
};
#define G (*ptr_to_globals)
#define INIT_G() do { \
    SET_PTR_TO_GLOBALS(xzalloc(sizeof(G))); \
} while (0)


/*
 * Allocates additional buffer space for width and more as needed.
 * The first call will allocate the first buffer.
 *
 * bufindex  the index that will be used after the call to this function.
 */
static void ensure_buffer_capacity(int bufindex)
{
    if (bufindex >= G.capacity) {
        G.capacity += 0x100;
        G.width = xrealloc(G.width, G.capacity * sizeof(G.width[0]));
        G.more = xrealloc(G.more, G.capacity * sizeof(G.more[0]));
    }
}

/* NB: this function is never called with "bad" chars
 * (control chars or chars >= 0x7f)
 */
static void out_char(char c)
{
    G.cur_x++;
    if (G.cur_x > G.output_width)
        return;
    if (G.cur_x == G.output_width)
        c = '+';
    putchar(c);
}

/* NB: this function is never called with "bad" chars
 * (control chars or chars >= 0x7f)
 */
static void out_string(const char *str)
{
    while (*str)
        out_char(*str++);
}

static void out_newline(void)
{
    putchar('\n');
    G.cur_x = 0;
}

static PROC *find_proc(pid_t pid)
{
    PROC *walk;

    for (walk = G.list; walk; walk = walk->next)
        if (walk->pid == pid)
            break;

    return walk;
}

static PROC *new_proc(const char *comm, pid_t pid, uid_t uid)
{
    PROC *new = xzalloc(sizeof(*new));

    strcpy(new->comm, comm);
    new->pid = pid;
    new->uid = uid;
    new->next = G.list;

    G.list = new;
    return G.list;
}

static void add_child(PROC *parent, PROC *child)
{
    CHILD *new, **walk;
    int cmp;

    new = xmalloc(sizeof(*new));

    new->child = child;
    for (walk = &parent->children; *walk; walk = &(*walk)->next) {
        cmp = strcmp((*walk)->child->comm, child->comm);
        if (cmp > 0)
            break;
        if (cmp == 0 && (*walk)->child->uid > child->uid)
            break;
    }
    new->next = *walk;
    *walk = new;
}

static void add_proc(const char *comm, pid_t pid, pid_t ppid,
            uid_t uid /*, char isthread*/)
{
    PROC *this, *parent;

    this = find_proc(pid);
    if (!this)
        this = new_proc(comm, pid, uid);
    else {
        strcpy(this->comm, comm);
        this->uid = uid;
    }

    if (pid == ppid)
        ppid = 0;
//  if (isthread)
//      this->flags |= PFLAG_THREAD;

    parent = find_proc(ppid);
    if (!parent)
        parent = new_proc("?", ppid, 0);

    add_child(parent, this);
    this->parent = parent;
}

static int tree_equal(const PROC *a, const PROC *b)
{
    const CHILD *walk_a, *walk_b;

    if (strcmp(a->comm, b->comm) != 0)
        return 0;
    if ((option_mask32 /*& OPT_PID*/) && a->pid != b->pid)
        return 0;

    for (walk_a = a->children, walk_b = b->children;
      walk_a && walk_b;
      walk_a = walk_a->next, walk_b = walk_b->next
    ) {
        if (!tree_equal(walk_a->child, walk_b->child))
            return 0;
    }

    return !(walk_a || walk_b);
}

static int out_args(const char *mystr)
{
    const char *here;
    int strcount = 0;
    char tmpstr[5];

    for (here = mystr; *here; here++) {
        if (*here == '\\') {
            out_string("\\\\");
            strcount += 2;
        } else if (*here >= ' ' && *here < 0x7f) {
            out_char(*here);
            strcount++;
        } else {
            sprintf(tmpstr, "\\%03o", (unsigned char) *here);
            out_string(tmpstr);
            strcount += 4;
        }
    }

    return strcount;
}

static void
dump_tree(PROC *current, int level, int rep, int leaf, int last, int closing)
{
    CHILD *walk, *next, **scan;
    int lvl, i, add, offset, count, comm_len, first;
    char tmp[sizeof(int)*3 + 4];

    if (!current)
        return;

    if (!leaf) {
        for (lvl = 0; lvl < level; lvl++) {
            i = G.width[lvl] + 1;
            while (--i >= 0)
                out_char(' ');

            if (lvl == level - 1) {
                if (last) {
                    out_string(last_2);
                } else {
                    out_string(branch_2);
                }
            } else {
                if (G.more[lvl + 1]) {
                    out_string(vert_2);
                } else {
                    out_string(empty_2);
                }
            }
        }
    }

    add = 0;
    if (rep > 1) {
        add += sprintf(tmp, "%d*[", rep);
        out_string(tmp);
    }
    comm_len = out_args(current->comm);
    if (option_mask32 /*& OPT_PID*/) {
        comm_len += sprintf(tmp, "(%d)", (int)current->pid);
        out_string(tmp);
    }
    offset = G.cur_x;

    if (!current->children) {
        while (closing--)
            out_char(']');
        out_newline();
    }
    ensure_buffer_capacity(level);
    G.more[level] = !last;

    G.width[level] = comm_len + G.cur_x - offset + add;
    if (G.cur_x >= G.output_width) {
        //out_string(first_3); - why? it won't print anything
        //out_char('+');
        out_newline();
        return;
    }

    first = 1;
    for (walk = current->children; walk; walk = next) {
        count = 0;
        next = walk->next;
        scan = &walk->next;
        while (*scan) {
            if (!tree_equal(walk->child, (*scan)->child))
                scan = &(*scan)->next;
            else {
                if (next == *scan)
                    next = (*scan)->next;
                count++;
                *scan = (*scan)->next;
            }
        }
        if (first) {
            out_string(next ? first_3 : single_3);
            first = 0;
        }

        dump_tree(walk->child, level + 1, count + 1,
                walk == current->children, !next,
                closing + (count ? 1 : 0));
    }
}

static void dump_by_user(PROC *current, uid_t uid)
{
    const CHILD *walk;

    if (!current)
        return;

    if (current->uid == uid) {
        if (G.dumped)
            putchar('\n');
        dump_tree(current, 0, 1, 1, 1, 0);
        G.dumped = 1;
        return;
    }
    for (walk = current->children; walk; walk = walk->next)
        dump_by_user(walk->child, uid);
}

#if ENABLE_FEATURE_SHOW_THREADS
static void handle_thread(const char *comm, pid_t pid, pid_t ppid, uid_t uid)
{
    char threadname[COMM_DISP_LEN + 1];
    sprintf(threadname, "{%.*s}", (int)sizeof(threadname) - 3, comm);
    add_proc(threadname, pid, ppid, uid/*, 1*/);
}
#endif

static void mread_proc(void)
{
    procps_status_t *p = NULL;
    pid_t parent = 0;
    int flags = PSSCAN_COMM | PSSCAN_PID | PSSCAN_PPID | PSSCAN_UIDGID | PSSCAN_TASKS;

    while ((p = procps_scan(p, flags)) != NULL) {
#if ENABLE_FEATURE_SHOW_THREADS
        if (p->pid != p->main_thread_pid)
            handle_thread(p->comm, p->pid, parent, p->uid);
        else
#endif
        {
            add_proc(p->comm, p->pid, p->ppid, p->uid/*, 0*/);
            parent = p->pid;
        }
    }
}

int pstree_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int pstree_main(int argc UNUSED_PARAM, char **argv)
{
    pid_t pid = 1;
    long uid = 0;

    INIT_G();

    G.output_width = get_terminal_width(0);

    opt_complementary = "?1";
    getopt32(argv, "p");
    argv += optind;

    if (argv[0]) {
        if (argv[0][0] >= '0' && argv[0][0] <= '9') {
            pid = xatoi(argv[0]);
        } else {
            uid = xuname2uid(argv[0]);
        }
    }

    mread_proc();

    if (!uid)
        dump_tree(find_proc(pid), 0, 1, 1, 1, 0);
    else {
        dump_by_user(find_proc(1), uid);
        if (!G.dumped) {
            bb_error_msg_and_die("no processes found");
        }
    }

    if (ENABLE_FEATURE_CLEAN_UP) {
        free(G.width);
        free(G.more);
    }
    return 0;
}