/*
 * 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 2008 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

/*
 * Copyright (c) 2019 Joyent, Inc.
 * Copyright (c) 2015 by Delphix. All rights reserved.
 */

#include <ctype.h>
#include <errno.h>
#include <limits.h>
#include <stdlib.h>
#include <string.h>
#include <dlfcn.h>
#include "umem_base.h"
#include "vmem_base.h"

/*
 * A umem environment variable, like UMEM_DEBUG, is set to a series
 * of items, seperated by ',':
 *
 *   UMEM_DEBUG="audit=10,guards,firewall=512"
 *
 * This structure describes items.  Each item has a name, type, and
 * description.  During processing, an item read from the user may
 * be either "valid" or "invalid".
 *
 * A valid item has an argument, if required, and it is of the right
 * form (doesn't overflow, doesn't contain any unexpected characters).
 *
 * If the item is valid, item_flag_target != NULL, and:
 *      type is not CLEARFLAG, then (*item_flag_target) |= item_flag_value
 *      type is CLEARFLAG, then (*item_flag_target) &= ~item_flag_value
 */

#define UMEM_ENV_ITEM_MAX       512

struct umem_env_item;

typedef int arg_process_t(const struct umem_env_item *item, const char *value);
#define ARG_SUCCESS     0       /* processing successful */
#define ARG_BAD         1       /* argument had a bad value */

typedef struct umem_env_item {
        const char *item_name;  /* tag in environment variable */
        const char *item_interface_stability;
        enum {
            ITEM_INVALID,
            ITEM_FLAG,          /* only a flag.  No argument allowed */
            ITEM_CLEARFLAG,     /* only a flag, but clear instead of set */
            ITEM_OPTUINT,       /* optional integer argument */
            ITEM_UINT,          /* required integer argument */
            ITEM_OPTSIZE,       /* optional size_t argument */
            ITEM_SIZE,          /* required size_t argument */
            ITEM_SPECIAL        /* special argument processing */
        } item_type;
        const char *item_description;
        uint_t *item_flag_target; /* the variable containing the flag */
        uint_t item_flag_value; /* the value to OR in */
        uint_t *item_uint_target; /* the variable to hold the integer */
        size_t *item_size_target;
        arg_process_t *item_special; /* callback for special handling */
} umem_env_item_t;

#ifndef UMEM_STANDALONE
static arg_process_t umem_backend_process;
static arg_process_t umem_allocator_process;
#endif

static arg_process_t umem_log_process;

static size_t umem_size_tempval;
static arg_process_t umem_size_process;

const char *____umem_environ_msg_options = "-- UMEM_OPTIONS --";

static umem_env_item_t umem_options_items[] = {
#ifndef UMEM_STANDALONE
        { "backend",            "Evolving",     ITEM_SPECIAL,
                "=sbrk for sbrk(2), =mmap for mmap(2)",
                NULL, 0, NULL, NULL,
                &umem_backend_process
        },
        { "allocator",          "Evolving",     ITEM_SPECIAL,
                "=best, =first, =next, or =instant",
                NULL, 0, NULL, NULL,
                &umem_allocator_process
        },
#endif

        { "concurrency",        "Private",      ITEM_UINT,
                "Max concurrency",
                NULL, 0,        &umem_max_ncpus
        },
        { "max_contention",     "Private",      ITEM_UINT,
                "Maximum contention in a reap interval before the depot is "
                    "resized.",
                NULL, 0,        &umem_depot_contention
        },
        { "nomagazines",        "Private",      ITEM_FLAG,
                "no caches will be multithreaded, and no caching will occur.",
                &umem_flags,    UMF_NOMAGAZINE
        },
        { "reap_interval",      "Private",      ITEM_UINT,
                "Minimum time between reaps and updates, in seconds.",
                NULL, 0,        &umem_reap_interval
        },

        { "size_add",           "Private",      ITEM_SPECIAL,
                "add a size to the cache size table",
                NULL, 0, NULL,
                &umem_size_tempval,             &umem_size_process
        },
        { "size_clear",         "Private",      ITEM_SPECIAL,
                "clear all but the largest size from the cache size table",
                NULL, 0, NULL,
                &umem_size_tempval,             &umem_size_process
        },
        { "size_remove",        "Private",      ITEM_SPECIAL,
            "remove a size from the cache size table",
                NULL, 0, NULL,
                &umem_size_tempval,             &umem_size_process
        },

#ifndef UMEM_STANDALONE
        { "sbrk_minalloc",      "Private",      ITEM_SIZE,
                "The minimum allocation chunk for the sbrk(2) heap.",
                NULL, 0, NULL,  &vmem_sbrk_minalloc
        },
        { "sbrk_pagesize",      "Private",      ITEM_SIZE,
                "The preferred page size for the sbrk(2) heap.",
                NULL, 0, NULL,  &vmem_sbrk_pagesize
        },
#endif
        { "perthread_cache",    "Evolving",     ITEM_SIZE,
                "Size (in bytes) of per-thread allocation cache",
                NULL, 0, NULL, &umem_ptc_size
        },
        { NULL, "-- end of UMEM_OPTIONS --",    ITEM_INVALID }
};

const char *____umem_environ_msg_debug = "-- UMEM_DEBUG --";

static umem_env_item_t umem_debug_items[] = {
        { "default",            "Unstable",     ITEM_FLAG,
                "audit,contents,guards",
                &umem_flags,
                UMF_AUDIT | UMF_CONTENTS | UMF_DEADBEEF | UMF_REDZONE
        },
        { "audit",              "Unstable",     ITEM_OPTUINT,
                "Enable auditing.  optionally =frames to set the number of "
                    "stored stack frames",
                &umem_flags,    UMF_AUDIT,      &umem_stack_depth
        },
        { "contents",           "Unstable",     ITEM_OPTSIZE,
                "Enable contents storing.  UMEM_LOGGING=contents also "
                    "required.  optionally =bytes to set the number of stored "
                    "bytes",
                &umem_flags,    UMF_CONTENTS, NULL,     &umem_content_maxsave
        },
        { "guards",             "Unstable",     ITEM_FLAG,
                "Enables guards and special patterns",
                &umem_flags,    UMF_DEADBEEF | UMF_REDZONE
        },
        { "verbose",            "Unstable",     ITEM_FLAG,
                "Enables writing error messages to stderr",
                &umem_output,   1
        },

        { "nosignal",   "Private",      ITEM_FLAG,
                "Abort if called from a signal handler.  Turns on 'audit'.  "
                    "Note that this is not always a bug.",
                &umem_flags,    UMF_AUDIT | UMF_CHECKSIGNAL
        },
        { "firewall",           "Private",      ITEM_SIZE,
                "=minbytes.  Every object >= minbytes in size will have its "
                    "end against an unmapped page",
                &umem_flags,    UMF_FIREWALL,   NULL,   &umem_minfirewall
        },
        { "lite",               "Private",      ITEM_FLAG,
                "debugging-lite",
                &umem_flags,    UMF_LITE
        },
        { "maxverify",          "Private",      ITEM_SIZE,
                "=maxbytes, Maximum bytes to check when 'guards' is active. "
                    "Normally all bytes are checked.",
                NULL, 0, NULL,  &umem_maxverify
        },
        { "noabort",            "Private",      ITEM_CLEARFLAG,
                "umem will not abort when a recoverable error occurs "
                    "(i.e. double frees, certain kinds of corruption)",
                &umem_abort,    1
        },
        { "mtbf",               "Private",      ITEM_UINT,
                "=mtbf, the mean time between injected failures.  Works best "
                    "if prime.\n",
                NULL, 0,        &umem_mtbf
        },
        { "random",             "Private",      ITEM_FLAG,
                "randomize flags on a per-cache basis",
                &umem_flags,    UMF_RANDOMIZE
        },
        { "allverbose",         "Private",      ITEM_FLAG,
                "Enables writing all logged messages to stderr",
                &umem_output,   2
        },
        { "checknull",          "Private",      ITEM_FLAG,
                "Abort if an allocation would return null",
                &umem_flags,    UMF_CHECKNULL
        },

        { NULL, "-- end of UMEM_DEBUG --",      ITEM_INVALID }
};

const char *____umem_environ_msg_logging = "-- UMEM_LOGGING --";

static umem_env_item_t umem_logging_items[] = {
        { "transaction",        "Unstable",     ITEM_SPECIAL,
                "If 'audit' is set in UMEM_DEBUG, the audit structures "
                    "from previous transactions are entered into this log.",
                NULL, 0, NULL,
                &umem_transaction_log_size,     &umem_log_process
        },
        { "contents",           "Unstable",     ITEM_SPECIAL,
                "If 'audit' is set in UMEM_DEBUG, the contents of objects "
                    "are recorded in this log as they are freed.  If the "
                    "'contents' option is not set in UMEM_DEBUG, the first "
                    "256 bytes of each freed buffer will be saved.",
                &umem_flags,    UMF_CONTENTS,   NULL,
                &umem_content_log_size,         &umem_log_process
        },
        { "fail",               "Unstable",     ITEM_SPECIAL,
                "Records are entered into this log for every failed "
                    "allocation.",
                NULL, 0, NULL,
                &umem_failure_log_size,         &umem_log_process
        },

        { "slab",               "Private",      ITEM_SPECIAL,
                "Every slab created will be entered into this log.",
                NULL, 0, NULL,
                &umem_slab_log_size,            &umem_log_process
        },

        { NULL, "-- end of UMEM_LOGGING --",    ITEM_INVALID }
};

typedef struct umem_envvar {
        const char *env_name;
        const char *env_func;
        umem_env_item_t *env_item_list;
        const char *env_getenv_result;
        const char *env_func_result;
} umem_envvar_t;

static umem_envvar_t umem_envvars[] = {
        { "UMEM_DEBUG",         "_umem_debug_init",     umem_debug_items },
        { "UMEM_OPTIONS",       "_umem_options_init",   umem_options_items },
        { "UMEM_LOGGING",       "_umem_logging_init",   umem_logging_items },
        { NULL, NULL, NULL }
};

static umem_envvar_t *env_current;
#define CURRENT         (env_current->env_name)

static int
empty(const char *str)
{
        char c;

        while ((c = *str) != '\0' && isspace(c))
                str++;

        return (*str == '\0');
}

static int
item_uint_process(const umem_env_item_t *item, const char *item_arg)
{
        ulong_t result;
        char *endptr = "";
        int olderrno;

        olderrno = errno;
        errno = 0;

        if (empty(item_arg)) {
                goto badnumber;
        }

        result = strtoul(item_arg, &endptr, 10);

        if (result == ULONG_MAX && errno == ERANGE) {
                errno = olderrno;
                goto overflow;
        }
        errno = olderrno;

        if (*endptr != '\0')
                goto badnumber;
        if ((uint_t)result != result)
                goto overflow;

        (*item->item_uint_target) = (uint_t)result;
        return (ARG_SUCCESS);

badnumber:
        log_message("%s: %s: not a number\n", CURRENT, item->item_name);
        return (ARG_BAD);

overflow:
        log_message("%s: %s: overflowed\n", CURRENT, item->item_name);
        return (ARG_BAD);
}

static int
item_size_process(const umem_env_item_t *item, const char *item_arg)
{
        ulong_t result;
        ulong_t result_arg;
        char *endptr = "";
        int olderrno;

        if (empty(item_arg))
                goto badnumber;

        olderrno = errno;
        errno = 0;

        result_arg = strtoul(item_arg, &endptr, 10);

        if (result_arg == ULONG_MAX && errno == ERANGE) {
                errno = olderrno;
                goto overflow;
        }
        errno = olderrno;

        result = result_arg;

        switch (*endptr) {
        case 't':
        case 'T':
                result *= 1024;
                if (result < result_arg)
                        goto overflow;
                /*FALLTHRU*/
        case 'g':
        case 'G':
                result *= 1024;
                if (result < result_arg)
                        goto overflow;
                /*FALLTHRU*/
        case 'm':
        case 'M':
                result *= 1024;
                if (result < result_arg)
                        goto overflow;
                /*FALLTHRU*/
        case 'k':
        case 'K':
                result *= 1024;
                if (result < result_arg)
                        goto overflow;
                endptr++;               /* skip over the size character */
                break;
        default:
                break;                  /* handled later */
        }

        if (*endptr != '\0')
                goto badnumber;

        (*item->item_size_target) = result;
        return (ARG_SUCCESS);

badnumber:
        log_message("%s: %s: not a number\n", CURRENT, item->item_name);
        return (ARG_BAD);

overflow:
        log_message("%s: %s: overflowed\n", CURRENT, item->item_name);
        return (ARG_BAD);
}

static int
umem_log_process(const umem_env_item_t *item, const char *item_arg)
{
        if (item_arg != NULL) {
                int ret;
                ret = item_size_process(item, item_arg);
                if (ret != ARG_SUCCESS)
                        return (ret);

                if (*item->item_size_target == 0)
                        return (ARG_SUCCESS);
        } else
                *item->item_size_target = 64*1024;

        umem_logging = 1;
        return (ARG_SUCCESS);
}

static int
umem_size_process(const umem_env_item_t *item, const char *item_arg)
{
        const char *name = item->item_name;
        void (*action_func)(size_t);

        size_t result;

        int ret;

        if (strcmp(name, "size_clear") == 0) {
                if (item_arg != NULL) {
                        log_message("%s: %s: does not take a value. ignored\n",
                            CURRENT, name);
                        return (ARG_BAD);
                }
                umem_alloc_sizes_clear();
                return (ARG_SUCCESS);
        } else if (strcmp(name, "size_add") == 0) {
                action_func = umem_alloc_sizes_add;
        } else if (strcmp(name, "size_remove") == 0) {
                action_func = umem_alloc_sizes_remove;
        } else {
                log_message("%s: %s: internally unrecognized\n",
                    CURRENT, name, name, name);
                return (ARG_BAD);
        }

        if (item_arg == NULL) {
                log_message("%s: %s: requires a value. ignored\n",
                    CURRENT, name);
                return (ARG_BAD);
        }

        ret = item_size_process(item, item_arg);
        if (ret != ARG_SUCCESS)
                return (ret);

        result = *item->item_size_target;
        action_func(result);
        return (ARG_SUCCESS);
}

#ifndef UMEM_STANDALONE
static int
umem_backend_process(const umem_env_item_t *item, const char *item_arg)
{
        const char *name = item->item_name;

        if (item_arg == NULL)
                goto fail;

        if (strcmp(item_arg, "sbrk") == 0)
                vmem_backend |= VMEM_BACKEND_SBRK;
        else if (strcmp(item_arg, "mmap") == 0)
                vmem_backend |= VMEM_BACKEND_MMAP;
        else
                goto fail;

        return (ARG_SUCCESS);

fail:
        log_message("%s: %s: must be %s=sbrk or %s=mmap\n",
            CURRENT, name, name, name);
        return (ARG_BAD);
}


static int
umem_allocator_process(const umem_env_item_t *item, const char *item_arg)
{
        const char *name = item->item_name;

        if (item_arg == NULL)
                goto fail;

        if (strcmp(item_arg, "best") == 0)
                vmem_allocator = VM_BESTFIT;
        else if (strcmp(item_arg, "next") == 0)
                vmem_allocator = VM_NEXTFIT;
        else if (strcmp(item_arg, "first") == 0)
                vmem_allocator = VM_FIRSTFIT;
        else if (strcmp(item_arg, "instant") == 0)
                vmem_allocator = 0;
        else
                goto fail;

        return (ARG_SUCCESS);

fail:
        log_message("%s: %s: must be %s=best, %s=next or %s=first\n",
            CURRENT, name, name, name, name);
        return (ARG_BAD);

}
#endif

static int
process_item(const umem_env_item_t *item, const char *item_arg)
{
        int arg_required = 0;
        arg_process_t *processor;

        switch (item->item_type) {
        case ITEM_FLAG:
        case ITEM_CLEARFLAG:
        case ITEM_OPTUINT:
        case ITEM_OPTSIZE:
        case ITEM_SPECIAL:
                arg_required = 0;
                break;

        case ITEM_UINT:
        case ITEM_SIZE:
                arg_required = 1;
                break;

        default:
                /*
                 * These are flags that aren't supported, so they'll error out
                 * below.
                 */
                break;
        }

        switch (item->item_type) {
        case ITEM_FLAG:
        case ITEM_CLEARFLAG:
                if (item_arg != NULL) {
                        log_message("%s: %s: does not take a value. ignored\n",
                            CURRENT, item->item_name);
                        return (1);
                }
                processor = NULL;
                break;

        case ITEM_UINT:
        case ITEM_OPTUINT:
                processor = item_uint_process;
                break;

        case ITEM_SIZE:
        case ITEM_OPTSIZE:
                processor = item_size_process;
                break;

        case ITEM_SPECIAL:
                processor = item->item_special;
                break;

        default:
                log_message("%s: %s: Invalid type.  Ignored\n",
                    CURRENT, item->item_name);
                return (1);
        }

        if (arg_required && item_arg == NULL) {
                log_message("%s: %s: Required value missing\n",
                    CURRENT, item->item_name);
                goto invalid;
        }

        if (item_arg != NULL || item->item_type == ITEM_SPECIAL) {
                if (processor(item, item_arg) != ARG_SUCCESS)
                        goto invalid;
        }

        if (item->item_flag_target) {
                if (item->item_type == ITEM_CLEARFLAG)
                        (*item->item_flag_target) &= ~item->item_flag_value;
                else
                        (*item->item_flag_target) |= item->item_flag_value;
        }
        return (0);

invalid:
        return (1);
}

#define ENV_SHORT_BYTES 10      /* bytes to print on error */
void
umem_process_value(umem_env_item_t *item_list, const char *beg, const char *end)
{
        char buf[UMEM_ENV_ITEM_MAX];
        char *argptr;

        size_t count;

        while (beg < end && isspace(*beg))
                beg++;

        while (beg < end && isspace(*(end - 1)))
                end--;

        if (beg >= end) {
                log_message("%s: empty option\n", CURRENT);
                return;
        }

        count = end - beg;

        if (count + 1 > sizeof (buf)) {
                char outbuf[ENV_SHORT_BYTES + 1];
                /*
                 * Have to do this, since sprintf("%10s",...) calls malloc()
                 */
                (void) strncpy(outbuf, beg, ENV_SHORT_BYTES);
                outbuf[ENV_SHORT_BYTES] = 0;

                log_message("%s: argument \"%s...\" too long\n", CURRENT,
                    outbuf);
                return;
        }

        (void) strncpy(buf, beg, count);
        buf[count] = 0;

        argptr = strchr(buf, '=');

        if (argptr != NULL)
                *argptr++ = 0;

        for (; item_list->item_name != NULL; item_list++) {
                if (strcmp(buf, item_list->item_name) == 0) {
                        (void) process_item(item_list, argptr);
                        return;
                }
        }
        log_message("%s: '%s' not recognized\n", CURRENT, buf);
}

/*ARGSUSED*/
void
umem_setup_envvars(int invalid)
{
        umem_envvar_t *cur_env;
        static volatile enum {
                STATE_START,
                STATE_GETENV,
                STATE_DLOPEN,
                STATE_DLSYM,
                STATE_FUNC,
                STATE_DONE
        } state = STATE_START;
#ifndef UMEM_STANDALONE
        void *h;
#endif

        if (invalid) {
                const char *where;
                /*
                 * One of the calls below invoked malloc() recursively.  We
                 * remove any partial results and return.
                 */

                switch (state) {
                case STATE_START:
                        where = "before getenv(3C) calls -- "
                            "getenv(3C) results ignored.";
                        break;
                case STATE_GETENV:
                        where = "during getenv(3C) calls -- "
                            "getenv(3C) results ignored.";
                        break;
                case STATE_DLOPEN:
                        where = "during dlopen(3C) call -- "
                            "_umem_*() results ignored.";
                        break;
                case STATE_DLSYM:
                        where = "during dlsym(3C) call -- "
                            "_umem_*() results ignored.";
                        break;
                case STATE_FUNC:
                        where = "during _umem_*() call -- "
                            "_umem_*() results ignored.";
                        break;
                case STATE_DONE:
                        where = "after dlsym() or _umem_*() calls.";
                        break;
                default:
                        where = "at unknown point -- "
                            "_umem_*() results ignored.";
                        break;
                }

                log_message("recursive allocation %s\n", where);

                for (cur_env = umem_envvars; cur_env->env_name != NULL;
                    cur_env++) {
                        if (state == STATE_GETENV)
                                cur_env->env_getenv_result = NULL;
                        if (state != STATE_DONE)
                                cur_env->env_func_result = NULL;
                }

                state = STATE_DONE;
                return;
        }

        state = STATE_GETENV;

        for (cur_env = umem_envvars; cur_env->env_name != NULL; cur_env++) {
                cur_env->env_getenv_result = getenv(cur_env->env_name);
                if (state == STATE_DONE)
                        return;         /* recursed */
        }

#ifndef UMEM_STANDALONE
        state = STATE_DLOPEN;

        /* get a handle to the "a.out" object */
        if ((h = dlopen(0, RTLD_FIRST | RTLD_LAZY)) != NULL) {
                for (cur_env = umem_envvars; cur_env->env_name != NULL;
                    cur_env++) {
                        const char *(*func)(void);
                        const char *value;

                        state = STATE_DLSYM;
                        func = (const char *(*)(void))dlsym(h,
                            cur_env->env_func);

                        if (state == STATE_DONE)
                                break;          /* recursed */

                        state = STATE_FUNC;
                        if (func != NULL) {
                                value = func();
                                if (state == STATE_DONE)
                                        break;          /* recursed */
                                cur_env->env_func_result = value;
                        }
                }
                (void) dlclose(h);
        } else {
                (void) dlerror();               /* snarf dlerror() */
        }
#endif /* UMEM_STANDALONE */

        state = STATE_DONE;
}

/*
 * Process the environment variables.
 */
void
umem_process_envvars(void)
{
        const char *value;
        const char *end, *next;
        umem_envvar_t *cur_env;

        for (cur_env = umem_envvars; cur_env->env_name != NULL; cur_env++) {
                env_current = cur_env;

                value = cur_env->env_getenv_result;
                if (value == NULL)
                        value = cur_env->env_func_result;

                /* ignore if missing or empty */
                if (value == NULL)
                        continue;

                for (end = value; *end != '\0'; value = next) {
                        end = strchr(value, ',');
                        if (end != NULL)
                                next = end + 1;         /* skip the comma */
                        else
                                next = end = value + strlen(value);

                        umem_process_value(cur_env->env_item_list, value, end);
                }
        }
}