common/mdb/mdb_whatis.c

	mdb_whatis.c revision 4a1c24318fe7c9bdae38ce58a2e4624597d297e2
/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */
/*
 * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

#include <sys/mdb_modapi.h>
#include <mdb/mdb.h>
#include <mdb/mdb_io.h>
#include <mdb/mdb_module.h>
#include <mdb/mdb_string.h>
#include <mdb/mdb_whatis.h>
#include <mdb/mdb_whatis_impl.h>
#include <limits.h>

static int whatis_debug = 0;

/* for bsearch;  r is an array of {base, size}, e points into w->w_addrs */
static int
find_range(const void *r, const void *e)
{
    const uintptr_t *range = r;
    uintptr_t el = *(const uintptr_t *)e;

    if (el < range[0])
        return (1);

    if ((el - range[0]) >= range[1])
        return (-1);

    return (0);
}

/* for qsort; simple uintptr comparator */
static int
uintptr_cmp(const void *l, const void *r)
{
    uintptr_t lhs = *(const uintptr_t *)l;
    uintptr_t rhs = *(const uintptr_t *)r;

    if (lhs < rhs)
        return (-1);
    if (lhs > rhs)
        return (1);
    return (0);
}

static const uintptr_t *
mdb_whatis_search(mdb_whatis_t *w, uintptr_t base, size_t size)
{
    uintptr_t range[2];

    range[0] = base;
    range[1] = size;

    return (bsearch(range, w->w_addrs, w->w_naddrs, sizeof (*w->w_addrs),
        find_range));
}

/*
 * Returns non-zero if and only if there is at least one address of interest
 * in the range [base, base+size).
 */
int
mdb_whatis_overlaps(mdb_whatis_t *w, uintptr_t base, size_t size)
{
    const uintptr_t *f;
    uint_t offset, cur;

    if (whatis_debug && w->w_magic != WHATIS_MAGIC) {
        mdb_warn(
            "mdb_whatis_overlaps(): bogus mdb_whatis_t pointer\n");
        return (0);
    }

    if (w->w_done || size == 0)
        return (0);

    if (base + size - 1 < base) {
        mdb_warn("mdb_whatis_overlaps(): [%p, %p+%p) overflows\n",
            base, base, size);
        return (0);
    }

    f = mdb_whatis_search(w, base, size);
    if (f == NULL)
        return (0);

    cur = offset = f - w->w_addrs;

    /*
     * We only return success if there's an address we'll actually
     * match in the range.  We can quickly check for the ALL flag
     * or a non-found address at our match point.
     */
    if ((w->w_flags & WHATIS_ALL) || !w->w_addrfound[cur])
        return (1);

    /* Search backwards then forwards for a non-found address */
    while (cur > 0) {
        cur--;

        if (w->w_addrs[cur] < base)
            break;

        if (!w->w_addrfound[cur])
            return (1);
    }

    for (cur = offset + 1; cur < w->w_naddrs; cur++) {
        if ((w->w_addrs[cur] - base) >= size)
            break;

        if (!w->w_addrfound[cur])
            return (1);
    }

    return (0);         /* everything has already been seen */
}

/*
 * Iteratively search our list of addresses for matches in [base, base+size).
 */
int
mdb_whatis_match(mdb_whatis_t *w, uintptr_t base, size_t size, uintptr_t *out)
{
    size_t offset;

    if (whatis_debug) {
        if (w->w_magic != WHATIS_MAGIC) {
            mdb_warn(
                "mdb_whatis_match(): bogus mdb_whatis_t pointer\n");
            goto done;
        }
    }

    if (w->w_done || size == 0)
        goto done;

    if (base + size - 1 < base) {
        mdb_warn("mdb_whatis_match(): [%p, %p+%x) overflows\n",
            base, base, size);
        return (0);
    }

    if ((offset = w->w_match_next) != 0 &&
        (base != w->w_match_base || size != w->w_match_size)) {
        mdb_warn("mdb_whatis_match(): new range [%p, %p+%p) "
            "while still searching [%p, %p+%p)\n",
            base, base, size,
            w->w_match_base, w->w_match_base, w->w_match_size);
        offset = 0;
    }

    if (offset == 0) {
        const uintptr_t *f = mdb_whatis_search(w, base, size);

        if (f == NULL)
            goto done;

        offset = (f - w->w_addrs);

        /* Walk backwards until we reach the first match */
        while (offset > 0 && w->w_addrs[offset - 1] >= base)
            offset--;

        w->w_match_base = base;
        w->w_match_size = size;
    }

    for (; offset < w->w_naddrs && ((w->w_addrs[offset] - base) < size);
        offset++) {

        *out = w->w_addrs[offset];
        w->w_match_next = offset + 1;

        if (w->w_addrfound[offset]) {
            /* if we're not seeing everything, skip it */
            if (!(w->w_flags & WHATIS_ALL))
                continue;

            return (1);
        }

        /* We haven't seen this address yet. */
        w->w_found++;
        w->w_addrfound[offset] = 1;

        /* If we've found them all, we're done */
        if (w->w_found == w->w_naddrs && !(w->w_flags & WHATIS_ALL))
            w->w_done = 1;

        return (1);
    }

done:
    w->w_match_next = 0;
    w->w_match_base = 0;
    w->w_match_size = 0;
    return (0);
}

/*
 * Report a pointer (addr) in an object beginning at (base) in standard
 * whatis-style.  (format, ...) are mdb_printf() arguments, to be printed
 * after the address information.  The caller is responsible for printing
 * a newline (either in format or after the call returns)
 */
/*ARGSUSED*/
void
mdb_whatis_report_object(mdb_whatis_t *w,
    uintptr_t addr, uintptr_t base, const char *format, ...)
{
    va_list alist;

    if (whatis_debug) {
        if (mdb_whatis_search(w, addr, 1) == NULL)
            mdb_warn("mdb_whatis_report_object(): addr "
                "%p is not a pointer of interest.\n", addr);
    }

    if (addr < base)
        mdb_warn("whatis: addr (%p) is less than base (%p)\n",
            addr, base);

    if (addr == base)
        mdb_printf("%p is ", addr);
    else
        mdb_printf("%p is %p+%p, ", addr, base, addr - base);

    if (format == NULL)
        return;

    va_start(alist, format);
    mdb_iob_vprintf(mdb.m_out, format, alist);
    va_end(alist);
}

/*
 * Report an address (addr), with symbolic information if available, in
 * standard whatis-style.  (format, ...) are mdb_printf() arguments, to be
 * printed after the address information.  The caller is responsible for
 * printing a newline (either in format or after the call returns)
 */
/*ARGSUSED*/
void
mdb_whatis_report_address(mdb_whatis_t *w, uintptr_t addr,
    const char *format, ...)
{
    GElf_Sym sym;
    va_list alist;

    if (whatis_debug) {
        if (mdb_whatis_search(w, addr, 1) == NULL)
            mdb_warn("mdb_whatis_report_adddress(): addr "
                "%p is not a pointer of interest.\n", addr);
    }

    mdb_printf("%p is ", addr);

    if (mdb_lookup_by_addr(addr, MDB_SYM_FUZZY, NULL, 0, &sym) != -1 &&
        (addr - (uintptr_t)sym.st_value) < sym.st_size) {
        mdb_printf("%a, ", addr);
    }

    va_start(alist, format);
    mdb_iob_vprintf(mdb.m_out, format, alist);
    va_end(alist);
}

uint_t
mdb_whatis_flags(mdb_whatis_t *w)
{
    /* Mask out the internal-only flags */
    return (w->w_flags & WHATIS_PUBLIC);
}

uint_t
mdb_whatis_done(mdb_whatis_t *w)
{
    return (w->w_done);
}

/*
 * Whatis callback list management
 */
typedef struct whatis_callback {
    uint64_t    wcb_index;
    mdb_module_t    *wcb_module;
    const char  *wcb_modname;
    char        *wcb_name;
    mdb_whatis_cb_f *wcb_func;
    void        *wcb_arg;
    uint_t      wcb_prio;
    uint_t      wcb_flags;
} whatis_callback_t;

static whatis_callback_t builtin_whatis[] = {
    { 0, NULL, "mdb", "mappings", whatis_run_mappings, NULL,
        WHATIS_PRIO_MIN, WHATIS_REG_NO_ID }
};
#define NBUILTINS   (sizeof (builtin_whatis) / sizeof (*builtin_whatis))

static whatis_callback_t *whatis_cb_start[NBUILTINS];
static whatis_callback_t **whatis_cb = NULL;    /* callback array */
static size_t whatis_cb_count;          /* count of callbacks */
static size_t whatis_cb_size;           /* size of whatis_cb array */
static uint64_t whatis_cb_index;        /* global count */

#define WHATIS_CB_SIZE_MIN  8   /* initial allocation size */

static int
whatis_cbcmp(const void *lhs, const void *rhs)
{
    whatis_callback_t *l = *(whatis_callback_t * const *)lhs;
    whatis_callback_t *r = *(whatis_callback_t * const *)rhs;
    int ret;

    /* First, handle NULLs; we want them at the end */
    if (l == NULL && r == NULL)
        return (0);
    if (l == NULL)
        return (1);
    if (r == NULL)
        return (-1);

    /* Next, compare priorities */
    if (l->wcb_prio < r->wcb_prio)
        return (-1);
    if (l->wcb_prio > r->wcb_prio)
        return (1);

    /* then module name */
    if ((ret = strcmp(l->wcb_modname, r->wcb_modname)) != 0)
        return (ret);

    /* and finally insertion order */
    if (l->wcb_index < r->wcb_index)
        return (-1);
    if (l->wcb_index > r->wcb_index)
        return (1);

    mdb_warn("whatis_cbcmp(): can't happen: duplicate indices\n");
    return (0);
}

static void
whatis_init(void)
{
    int idx;

    for (idx = 0; idx < NBUILTINS; idx++) {
        whatis_cb_start[idx] = &builtin_whatis[idx];
        whatis_cb_start[idx]->wcb_index = idx;
    }
    whatis_cb_index = idx;

    whatis_cb = whatis_cb_start;
    whatis_cb_count = whatis_cb_size = NBUILTINS;

    qsort(whatis_cb, whatis_cb_count, sizeof (*whatis_cb), whatis_cbcmp);
}

void
mdb_whatis_register(const char *name, mdb_whatis_cb_f *func, void *arg,
    uint_t prio, uint_t flags)
{
    whatis_callback_t *wcp;

    if (mdb.m_lmod == NULL) {
        mdb_warn("mdb_whatis_register(): can only be called during "
            "module load\n");
        return;
    }

    if (strbadid(name)) {
        mdb_warn("mdb_whatis_register(): whatis name '%s' contains "
            "illegal characters\n");
        return;
    }

    if ((flags & ~(WHATIS_REG_NO_ID|WHATIS_REG_ID_ONLY)) != 0) {
        mdb_warn("mdb_whatis_register(): flags (%x) contain unknown "
            "flags\n", flags);
        return;
    }
    if ((flags & WHATIS_REG_NO_ID) && (flags & WHATIS_REG_ID_ONLY)) {
        mdb_warn("mdb_whatis_register(): flags (%x) contains both "
            "NO_ID and ID_ONLY.\n", flags);
        return;
    }

    if (prio > WHATIS_PRIO_MIN)
        prio = WHATIS_PRIO_MIN;

    if (whatis_cb == NULL)
        whatis_init();

    wcp = mdb_zalloc(sizeof (*wcp), UM_SLEEP);

    wcp->wcb_index = whatis_cb_index++;
    wcp->wcb_prio = prio;
    wcp->wcb_module = mdb.m_lmod;
    wcp->wcb_modname = mdb.m_lmod->mod_name;
    wcp->wcb_name = strdup(name);
    wcp->wcb_func = func;
    wcp->wcb_arg = arg;
    wcp->wcb_flags = flags;

    /*
     * See if we need to grow the array;  note that at initialization
     * time, whatis_cb_count is greater than whatis_cb_size; this clues
     * us in to the fact that the array doesn't need to be freed.
     */
    if (whatis_cb_count == whatis_cb_size) {
        size_t nsize = MAX(2 * whatis_cb_size, WHATIS_CB_SIZE_MIN);

        size_t obytes = sizeof (*whatis_cb) * whatis_cb_size;
        size_t nbytes = sizeof (*whatis_cb) * nsize;

        whatis_callback_t **narray = mdb_zalloc(nbytes, UM_SLEEP);

        bcopy(whatis_cb, narray, obytes);

        if (whatis_cb != whatis_cb_start)
            mdb_free(whatis_cb, obytes);
        whatis_cb = narray;
        whatis_cb_size = nsize;
    }

    /* add it into the table and re-sort */
    whatis_cb[whatis_cb_count++] = wcp;
    qsort(whatis_cb, whatis_cb_count, sizeof (*whatis_cb), whatis_cbcmp);
}

void
mdb_whatis_unregister_module(mdb_module_t *mod)
{
    int found = 0;
    int idx;

    if (mod == NULL)
        return;

    for (idx = 0; idx < whatis_cb_count; idx++) {
        whatis_callback_t *cur = whatis_cb[idx];

        if (cur->wcb_module == mod) {
            found++;
            whatis_cb[idx] = NULL;

            strfree(cur->wcb_name);
            mdb_free(cur, sizeof (*cur));
        }
    }
    /* If any were removed, compact the array */
    if (found != 0) {
        qsort(whatis_cb, whatis_cb_count, sizeof (*whatis_cb),
            whatis_cbcmp);
        whatis_cb_count -= found;
    }
}

int
cmd_whatis(uintptr_t addr, uint_t flags, int argc, const mdb_arg_t *argv)
{
    mdb_whatis_t w;
    size_t idx;
    int ret;
    int keep = 0;
    int list = 0;

    if (flags & DCMD_PIPE_OUT) {
        mdb_warn("whatis: cannot be output into a pipe\n");
        return (DCMD_ERR);
    }

    if (mdb.m_lmod != NULL) {
        mdb_warn("whatis: cannot be called during module load\n");
        return (DCMD_ERR);
    }

    if (whatis_cb == NULL)
        whatis_init();

    bzero(&w, sizeof (w));
    w.w_magic = WHATIS_MAGIC;

    whatis_debug = 0;

    if (mdb_getopts(argc, argv,
        'D', MDB_OPT_SETBITS, TRUE, &whatis_debug,      /* hidden */
        'b', MDB_OPT_SETBITS, WHATIS_BUFCTL, &w.w_flags,    /* hidden */
        'l', MDB_OPT_SETBITS, TRUE, &list,          /* hidden */
        'a', MDB_OPT_SETBITS, WHATIS_ALL, &w.w_flags,
        'i', MDB_OPT_SETBITS, WHATIS_IDSPACE, &w.w_flags,
        'k', MDB_OPT_SETBITS, TRUE, &keep,
        'q', MDB_OPT_SETBITS, WHATIS_QUIET, &w.w_flags,
        'v', MDB_OPT_SETBITS, WHATIS_VERBOSE, &w.w_flags,
        NULL) != argc)
        return (DCMD_USAGE);

    if (list) {
        mdb_printf("%<u>%-16s %-12s %4s %?s %?s %8s%</u>",
            "NAME", "MODULE", "PRIO", "FUNC", "ARG", "FLAGS");

        for (idx = 0; idx < whatis_cb_count; idx++) {
            whatis_callback_t *cur = whatis_cb[idx];

            const char *curfl =
                (cur->wcb_flags & WHATIS_REG_NO_ID) ? "NO_ID" :
                (cur->wcb_flags & WHATIS_REG_ID_ONLY) ? "ID_ONLY" :
                "none";

            mdb_printf("%-16s %-12s %4d %-?p %-?p %8s\n",
                cur->wcb_name, cur->wcb_modname, cur->wcb_prio,
                cur->wcb_func, cur->wcb_arg, curfl);
        }
        return (DCMD_OK);
    }

    if (!(flags & DCMD_ADDRSPEC))
        return (DCMD_USAGE);

    w.w_addrs = &addr;
    w.w_naddrs = 1;

    /* If our input is a pipe, try to slurp it all up. */
    if (!keep && (flags & DCMD_PIPE)) {
        mdb_pipe_t p;
        mdb_get_pipe(&p);

        if (p.pipe_len != 0) {
            w.w_addrs = p.pipe_data;
            w.w_naddrs = p.pipe_len;

            /* sort the address list */
            qsort(w.w_addrs, w.w_naddrs, sizeof (*w.w_addrs),
                uintptr_cmp);
        }
    }
    w.w_addrfound = mdb_zalloc(w.w_naddrs * sizeof (*w.w_addrfound),
        UM_SLEEP | UM_GC);

    if (whatis_debug) {
        mdb_printf("Searching for:\n");
        for (idx = 0; idx < w.w_naddrs; idx++)
            mdb_printf("    %p", w.w_addrs[idx]);
    }

    ret = 0;

    /* call in to the registered handlers */
    for (idx = 0; idx < whatis_cb_count; idx++) {
        whatis_callback_t *cur = whatis_cb[idx];

        /* Honor the ident flags */
        if (w.w_flags & WHATIS_IDSPACE) {
            if (cur->wcb_flags & WHATIS_REG_NO_ID)
                continue;
        } else {
            if (cur->wcb_flags & WHATIS_REG_ID_ONLY)
                continue;
        }

        if (w.w_flags & WHATIS_VERBOSE)
            mdb_printf("Searching %s`%s...\n",
                cur->wcb_modname, cur->wcb_name);

        if (cur->wcb_func(&w, cur->wcb_arg) != 0)
            ret = 1;

        /* reset the match state for the next callback */
        w.w_match_next = 0;
        w.w_match_base = 0;
        w.w_match_size = 0;

        if (w.w_done)
            break;
    }

    /* Report any unexplained pointers */
    for (idx = 0; idx < w.w_naddrs; idx++) {
        uintptr_t addr = w.w_addrs[idx];

        if (w.w_addrfound[idx])
            continue;

        mdb_whatis_report_object(&w, addr, addr, "unknown\n");
    }

    return ((ret != 0) ? DCMD_ERR : DCMD_OK);
}

void
whatis_help(void)
{
    int idx;

    mdb_printf("%s\n",
"Given a virtual address (with -i, an identifier), report where it came\n"
"from.\n"
"\n"
"When fed from a pipeline, ::whatis will not maintain the order the input\n"
"comes in; addresses will be reported as it finds them. (-k prevents this;\n"
"the output will be in the same order as the input)\n");
    (void) mdb_dec_indent(2);
    mdb_printf("%<b>OPTIONS%</b>\n");
    (void) mdb_inc_indent(2);
    mdb_printf("%s",
"  -a  Report all information about each address/identifier.  The default\n"
"      behavior is to report only the first (most specific) source for each\n"
"      address/identifier.\n"
"  -i  addr is an identifier, not a virtual address.\n"
"  -k  Do not re-order the input. (may be slower)\n"
"  -q  Quiet; don't print multi-line reports. (stack traces, etc.)\n"
"  -v  Verbose output; display information about the progress of the search\n");

    if (mdb.m_lmod != NULL)
        return;

    (void) mdb_dec_indent(2);
    mdb_printf("\n%<b>SOURCES%</b>\n\n");
    (void) mdb_inc_indent(2);
    mdb_printf("The following information sources will be used:\n\n");

    (void) mdb_inc_indent(2);
    for (idx = 0; idx < whatis_cb_count; idx++) {
        whatis_callback_t *cur = whatis_cb[idx];

        mdb_printf("%s`%s\n", cur->wcb_modname, cur->wcb_name);
    }
    (void) mdb_dec_indent(2);
}