/*
 * An implementation of key value pair (KVP) functionality for Linux.
 *
 *
 * Copyright (C) 2010, Novell, Inc.
 * Author : K. Y. Srinivasan <ksrinivasan@novell.com>
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 as published
 * by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
 * NON INFRINGEMENT.  See the GNU General Public License for more
 * details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 */


#include <sys/poll.h>
#include <sys/utsname.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <ctype.h>
#include <errno.h>
#include <arpa/inet.h>
#include <linux/hyperv.h>
#include <ifaddrs.h>
#include <netdb.h>
#include <syslog.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <dirent.h>
#include <net/if.h>
#include <limits.h>
#include <getopt.h>

/*
 * KVP protocol: The user mode component first registers with the
 * kernel component. Subsequently, the kernel component requests, data
 * for the specified keys. In response to this message the user mode component
 * fills in the value corresponding to the specified key. We overload the
 * sequence field in the cn_msg header to define our KVP message types.
 *
 * We use this infrastructure for also supporting queries from user mode
 * application for state that may be maintained in the KVP kernel component.
 *
 */


enum key_index {
        FullyQualifiedDomainName = 0,
        IntegrationServicesVersion, /*This key is serviced in the kernel*/
        NetworkAddressIPv4,
        NetworkAddressIPv6,
        OSBuildNumber,
        OSName,
        OSMajorVersion,
        OSMinorVersion,
        OSVersion,
        ProcessorArchitecture
};


enum {
        IPADDR = 0,
        NETMASK,
        GATEWAY,
        DNS
};

enum {
        IPV4 = 1,
        IPV6,
        IP_TYPE_MAX
};

static int in_hand_shake;
static int debug;

static char *os_name = "";
static char *os_major = "";
static char *os_minor = "";
static char *processor_arch;
static char *os_build;
static char *os_version;
static char *lic_version = "Unknown version";
static char full_domain_name[HV_KVP_EXCHANGE_MAX_VALUE_SIZE];
static struct utsname uts_buf;

/*
 * The location of the interface configuration file.
 */

#define KVP_CONFIG_LOC  "/var/lib/hyperv"

#ifndef KVP_SCRIPTS_PATH
#define KVP_SCRIPTS_PATH "/usr/libexec/hypervkvpd/"
#endif

#define KVP_NET_DIR "/sys/class/net/"

#define MAX_FILE_NAME 100
#define ENTRIES_PER_BLOCK 50
/*
 * Change this entry if the number of addresses increases in future
 */
#define MAX_IP_ENTRIES 64
#define OUTSTR_BUF_SIZE ((INET6_ADDRSTRLEN + 1) * MAX_IP_ENTRIES)

struct kvp_record {
        char key[HV_KVP_EXCHANGE_MAX_KEY_SIZE];
        char value[HV_KVP_EXCHANGE_MAX_VALUE_SIZE];
};

struct kvp_file_state {
        int fd;
        int num_blocks;
        struct kvp_record *records;
        int num_records;
        char fname[MAX_FILE_NAME];
};

static struct kvp_file_state kvp_file_info[KVP_POOL_COUNT];

static void kvp_acquire_lock(int pool)
{
        struct flock fl = {F_WRLCK, SEEK_SET, 0, 0, 0};
        fl.l_pid = getpid();

        if (fcntl(kvp_file_info[pool].fd, F_SETLKW, &fl) == -1) {
                syslog(LOG_ERR, "Failed to acquire the lock pool: %d; error: %d %s", pool,
                                errno, strerror(errno));
                exit(EXIT_FAILURE);
        }
}

static void kvp_release_lock(int pool)
{
        struct flock fl = {F_UNLCK, SEEK_SET, 0, 0, 0};
        fl.l_pid = getpid();

        if (fcntl(kvp_file_info[pool].fd, F_SETLK, &fl) == -1) {
                syslog(LOG_ERR, "Failed to release the lock pool: %d; error: %d %s", pool,
                                errno, strerror(errno));
                exit(EXIT_FAILURE);
        }
}

static void kvp_update_file(int pool)
{
        FILE *filep;

        /*
         * We are going to write our in-memory registry out to
         * disk; acquire the lock first.
         */
        kvp_acquire_lock(pool);

        filep = fopen(kvp_file_info[pool].fname, "we");
        if (!filep) {
                syslog(LOG_ERR, "Failed to open file, pool: %d; error: %d %s", pool,
                                errno, strerror(errno));
                kvp_release_lock(pool);
                exit(EXIT_FAILURE);
        }

        fwrite(kvp_file_info[pool].records, sizeof(struct kvp_record),
                                kvp_file_info[pool].num_records, filep);

        if (ferror(filep) || fclose(filep)) {
                kvp_release_lock(pool);
                syslog(LOG_ERR, "Failed to write file, pool: %d", pool);
                exit(EXIT_FAILURE);
        }

        kvp_release_lock(pool);
}

static void kvp_dump_initial_pools(int pool)
{
        int i;

        syslog(LOG_DEBUG, "===Start dumping the contents of pool %d ===\n",
               pool);

        for (i = 0; i < kvp_file_info[pool].num_records; i++)
                syslog(LOG_DEBUG, "pool: %d, %d/%d key=%s val=%s\n",
                       pool, i + 1, kvp_file_info[pool].num_records,
                       kvp_file_info[pool].records[i].key,
                       kvp_file_info[pool].records[i].value);
}

static void kvp_update_mem_state(int pool)
{
        FILE *filep;
        size_t records_read = 0;
        struct kvp_record *record = kvp_file_info[pool].records;
        struct kvp_record *readp;
        int num_blocks = kvp_file_info[pool].num_blocks;
        int alloc_unit = sizeof(struct kvp_record) * ENTRIES_PER_BLOCK;

        kvp_acquire_lock(pool);

        filep = fopen(kvp_file_info[pool].fname, "re");
        if (!filep) {
                syslog(LOG_ERR, "Failed to open file, pool: %d; error: %d %s", pool,
                                errno, strerror(errno));
                kvp_release_lock(pool);
                exit(EXIT_FAILURE);
        }
        for (;;) {
                readp = &record[records_read];
                records_read += fread(readp, sizeof(struct kvp_record),
                                ENTRIES_PER_BLOCK * num_blocks - records_read,
                                filep);

                if (ferror(filep)) {
                        syslog(LOG_ERR,
                                "Failed to read file, pool: %d; error: %d %s",
                                 pool, errno, strerror(errno));
                        kvp_release_lock(pool);
                        exit(EXIT_FAILURE);
                }

                if (!feof(filep)) {
                        /*
                         * We have more data to read.
                         */
                        num_blocks++;
                        record = realloc(record, alloc_unit * num_blocks);

                        if (record == NULL) {
                                syslog(LOG_ERR, "malloc failed");
                                kvp_release_lock(pool);
                                exit(EXIT_FAILURE);
                        }
                        continue;
                }
                break;
        }

        kvp_file_info[pool].num_blocks = num_blocks;
        kvp_file_info[pool].records = record;
        kvp_file_info[pool].num_records = records_read;

        fclose(filep);
        kvp_release_lock(pool);
}

static int kvp_file_init(void)
{
        int  fd;
        char *fname;
        int i;
        int alloc_unit = sizeof(struct kvp_record) * ENTRIES_PER_BLOCK;

        if (access(KVP_CONFIG_LOC, F_OK)) {
                if (mkdir(KVP_CONFIG_LOC, 0755 /* rwxr-xr-x */)) {
                        syslog(LOG_ERR, "Failed to create '%s'; error: %d %s", KVP_CONFIG_LOC,
                                        errno, strerror(errno));
                        exit(EXIT_FAILURE);
                }
        }

        for (i = 0; i < KVP_POOL_COUNT; i++) {
                fname = kvp_file_info[i].fname;
                sprintf(fname, "%s/.kvp_pool_%d", KVP_CONFIG_LOC, i);
                fd = open(fname, O_RDWR | O_CREAT | O_CLOEXEC, 0644 /* rw-r--r-- */);

                if (fd == -1)
                        return 1;

                kvp_file_info[i].fd = fd;
                kvp_file_info[i].num_blocks = 1;
                kvp_file_info[i].records = malloc(alloc_unit);
                if (kvp_file_info[i].records == NULL)
                        return 1;
                kvp_file_info[i].num_records = 0;
                kvp_update_mem_state(i);
                if (debug)
                        kvp_dump_initial_pools(i);
        }

        return 0;
}

static int kvp_key_delete(int pool, const __u8 *key, int key_size)
{
        int i;
        int j, k;
        int num_records;
        struct kvp_record *record;

        /*
         * First update the in-memory state.
         */
        kvp_update_mem_state(pool);

        num_records = kvp_file_info[pool].num_records;
        record = kvp_file_info[pool].records;

        for (i = 0; i < num_records; i++) {
                if (memcmp(key, record[i].key, key_size))
                        continue;
                /*
                 * Found a match; just move the remaining
                 * entries up.
                 */
                if (debug)
                        syslog(LOG_DEBUG, "%s: deleting the KVP: pool=%d key=%s val=%s",
                               __func__, pool, record[i].key, record[i].value);
                if (i == (num_records - 1)) {
                        kvp_file_info[pool].num_records--;
                        kvp_update_file(pool);
                        return 0;
                }

                j = i;
                k = j + 1;
                for (; k < num_records; k++) {
                        strcpy(record[j].key, record[k].key);
                        strcpy(record[j].value, record[k].value);
                        j++;
                }

                kvp_file_info[pool].num_records--;
                kvp_update_file(pool);
                return 0;
        }

        if (debug)
                syslog(LOG_DEBUG, "%s: could not delete KVP: pool=%d key=%s. Record not found",
                       __func__, pool, key);

        return 1;
}

static int kvp_key_add_or_modify(int pool, const __u8 *key, int key_size,
                                 const __u8 *value, int value_size)
{
        struct kvp_record *record;
        int num_records;
        int num_blocks;
        int i;

        if (debug)
                syslog(LOG_DEBUG, "%s: got a KVP: pool=%d key=%s val=%s",
                       __func__, pool, key, value);

        if ((key_size > HV_KVP_EXCHANGE_MAX_KEY_SIZE) ||
                (value_size > HV_KVP_EXCHANGE_MAX_VALUE_SIZE)) {
                syslog(LOG_ERR, "%s: Too long key or value: key=%s, val=%s",
                       __func__, key, value);

                if (debug)
                        syslog(LOG_DEBUG, "%s: Too long key or value: pool=%d, key=%s, val=%s",
                               __func__, pool, key, value);
                return 1;
        }

        /*
         * First update the in-memory state.
         */
        kvp_update_mem_state(pool);

        num_records = kvp_file_info[pool].num_records;
        record = kvp_file_info[pool].records;
        num_blocks = kvp_file_info[pool].num_blocks;

        for (i = 0; i < num_records; i++) {
                if (memcmp(key, record[i].key, key_size))
                        continue;
                /*
                 * Found a match; just update the value -
                 * this is the modify case.
                 */
                memcpy(record[i].value, value, value_size);
                kvp_update_file(pool);
                if (debug)
                        syslog(LOG_DEBUG, "%s: updated: pool=%d key=%s val=%s",
                               __func__, pool, key, value);
                return 0;
        }

        /*
         * Need to add a new entry;
         */
        if (num_records == (ENTRIES_PER_BLOCK * num_blocks)) {
                /* Need to allocate a larger array for reg entries. */
                record = realloc(record, sizeof(struct kvp_record) *
                         ENTRIES_PER_BLOCK * (num_blocks + 1));

                if (!record) {
                        syslog(LOG_ERR, "%s: Memory alloc failure", __func__);
                        return 1;
                }
                kvp_file_info[pool].num_blocks++;

        }
        memcpy(record[i].value, value, value_size);
        memcpy(record[i].key, key, key_size);
        kvp_file_info[pool].records = record;
        kvp_file_info[pool].num_records++;

        if (debug)
                syslog(LOG_DEBUG, "%s: added: pool=%d key=%s val=%s",
                       __func__, pool, key, value);

        kvp_update_file(pool);
        return 0;
}

static int kvp_get_value(int pool, const __u8 *key, int key_size, __u8 *value,
                        int value_size)
{
        int i;
        int num_records;
        struct kvp_record *record;

        if ((key_size > HV_KVP_EXCHANGE_MAX_KEY_SIZE) ||
                (value_size > HV_KVP_EXCHANGE_MAX_VALUE_SIZE))
                return 1;

        /*
         * First update the in-memory state.
         */
        kvp_update_mem_state(pool);

        num_records = kvp_file_info[pool].num_records;
        record = kvp_file_info[pool].records;

        for (i = 0; i < num_records; i++) {
                if (memcmp(key, record[i].key, key_size))
                        continue;
                /*
                 * Found a match; just copy the value out.
                 */
                memcpy(value, record[i].value, value_size);
                return 0;
        }

        return 1;
}

static int kvp_pool_enumerate(int pool, int index, __u8 *key, int key_size,
                                __u8 *value, int value_size)
{
        struct kvp_record *record;

        /*
         * First update our in-memory database.
         */
        kvp_update_mem_state(pool);
        record = kvp_file_info[pool].records;

        if (index >= kvp_file_info[pool].num_records) {
                return 1;
        }

        memcpy(key, record[index].key, key_size);
        memcpy(value, record[index].value, value_size);
        return 0;
}


void kvp_get_os_info(void)
{
        FILE    *file;
        char    *p, buf[512];

        uname(&uts_buf);
        os_version = uts_buf.release;
        os_build = strdup(uts_buf.release);

        os_name = uts_buf.sysname;
        processor_arch = uts_buf.machine;

        /*
         * The current windows host (win7) expects the build
         * string to be of the form: x.y.z
         * Strip additional information we may have.
         */
        p = strchr(os_version, '-');
        if (p)
                *p = '\0';

        /*
         * Parse the /etc/os-release file if present:
         * https://www.freedesktop.org/software/systemd/man/os-release.html
         */
        file = fopen("/etc/os-release", "r");
        if (file != NULL) {
                while (fgets(buf, sizeof(buf), file)) {
                        char *value, *q;

                        /* Ignore comments */
                        if (buf[0] == '#')
                                continue;

                        /* Split into name=value */
                        p = strchr(buf, '=');
                        if (!p)
                                continue;
                        *p++ = 0;

                        /* Remove quotes and newline; un-escape */
                        value = p;
                        q = p;
                        while (*p) {
                                if (*p == '\\') {
                                        ++p;
                                        if (!*p)
                                                break;
                                        *q++ = *p++;
                                } else if (*p == '\'' || *p == '"' ||
                                           *p == '\n') {
                                        ++p;
                                } else {
                                        *q++ = *p++;
                                }
                        }
                        *q = 0;

                        if (!strcmp(buf, "NAME")) {
                                p = strdup(value);
                                if (!p)
                                        break;
                                os_name = p;
                        } else if (!strcmp(buf, "VERSION_ID")) {
                                p = strdup(value);
                                if (!p)
                                        break;
                                os_major = p;
                        }
                }
                fclose(file);
                return;
        }

        /* Fallback for older RH/SUSE releases */
        file = fopen("/etc/SuSE-release", "r");
        if (file != NULL)
                goto kvp_osinfo_found;
        file  = fopen("/etc/redhat-release", "r");
        if (file != NULL)
                goto kvp_osinfo_found;

        /*
         * We don't have information about the os.
         */
        return;

kvp_osinfo_found:
        /* up to three lines */
        p = fgets(buf, sizeof(buf), file);
        if (p) {
                p = strchr(buf, '\n');
                if (p)
                        *p = '\0';
                p = strdup(buf);
                if (!p)
                        goto done;
                os_name = p;

                /* second line */
                p = fgets(buf, sizeof(buf), file);
                if (p) {
                        p = strchr(buf, '\n');
                        if (p)
                                *p = '\0';
                        p = strdup(buf);
                        if (!p)
                                goto done;
                        os_major = p;

                        /* third line */
                        p = fgets(buf, sizeof(buf), file);
                        if (p)  {
                                p = strchr(buf, '\n');
                                if (p)
                                        *p = '\0';
                                p = strdup(buf);
                                if (p)
                                        os_minor = p;
                        }
                }
        }

done:
        fclose(file);
        return;
}



/*
 * Retrieve an interface name corresponding to the specified guid.
 * If there is a match, the function returns a pointer
 * to the interface name and if not, a NULL is returned.
 * If a match is found, the caller is responsible for
 * freeing the memory.
 */

static char *kvp_get_if_name(char *guid)
{
        DIR *dir;
        struct dirent *entry;
        FILE    *file;
        char    *p, *x;
        char    *if_name = NULL;
        char    buf[256];
        char dev_id[PATH_MAX];

        dir = opendir(KVP_NET_DIR);
        if (dir == NULL)
                return NULL;

        while ((entry = readdir(dir)) != NULL) {
                /*
                 * Set the state for the next pass.
                 */
                snprintf(dev_id, sizeof(dev_id), "%s%s/device/device_id",
                         KVP_NET_DIR, entry->d_name);

                file = fopen(dev_id, "r");
                if (file == NULL)
                        continue;

                p = fgets(buf, sizeof(buf), file);
                if (p) {
                        x = strchr(p, '\n');
                        if (x)
                                *x = '\0';

                        if (!strcmp(p, guid)) {
                                /*
                                 * Found the guid match; return the interface
                                 * name. The caller will free the memory.
                                 */
                                if_name = strdup(entry->d_name);
                                fclose(file);
                                break;
                        }
                }
                fclose(file);
        }

        closedir(dir);
        return if_name;
}

/*
 * Retrieve the MAC address given the interface name.
 */

static char *kvp_if_name_to_mac(char *if_name)
{
        FILE    *file;
        char    *p, *x;
        char    buf[256];
        char addr_file[PATH_MAX];
        unsigned int i;
        char *mac_addr = NULL;

        snprintf(addr_file, sizeof(addr_file), "%s%s%s", KVP_NET_DIR,
                 if_name, "/address");

        file = fopen(addr_file, "r");
        if (file == NULL)
                return NULL;

        p = fgets(buf, sizeof(buf), file);
        if (p) {
                x = strchr(p, '\n');
                if (x)
                        *x = '\0';
                for (i = 0; i < strlen(p); i++)
                        p[i] = toupper(p[i]);
                mac_addr = strdup(p);
        }

        fclose(file);
        return mac_addr;
}

static void kvp_process_ipconfig_file(char *cmd,
                                        char *config_buf, unsigned int len,
                                        int element_size, int offset)
{
        char buf[256];
        char *p;
        char *x;
        FILE *file;

        /*
         * First execute the command.
         */
        file = popen(cmd, "r");
        if (file == NULL)
                return;

        if (offset == 0)
                memset(config_buf, 0, len);
        while ((p = fgets(buf, sizeof(buf), file)) != NULL) {
                if (len < strlen(config_buf) + element_size + 1)
                        break;

                x = strchr(p, '\n');
                if (x)
                        *x = '\0';

                strcat(config_buf, p);
                strcat(config_buf, ";");
        }
        pclose(file);
}

static bool kvp_verify_ip_address(const void *address_string)
{
        char verify_buf[sizeof(struct in6_addr)];

        if (inet_pton(AF_INET, address_string, verify_buf) == 1)
                return true;
        if (inet_pton(AF_INET6, address_string, verify_buf) == 1)
                return true;
        return false;
}

static void kvp_extract_routes(const char *line, void **output, size_t *remaining)
{
        static const char needle[] = "via ";
        const char *match, *haystack = line;

        while ((match = strstr(haystack, needle))) {
                const char *address, *next_char;

                /* Address starts after needle. */
                address = match + strlen(needle);

                /* The char following address is a space or end of line. */
                next_char = strpbrk(address, " \t\\");
                if (!next_char)
                        next_char = address + strlen(address) + 1;

                /* Enough room for address and semicolon. */
                if (*remaining >= (next_char - address) + 1) {
                        memcpy(*output, address, next_char - address);
                        /* Terminate string for verification. */
                        memcpy(*output + (next_char - address), "", 1);
                        if (kvp_verify_ip_address(*output)) {
                                /* Advance output buffer. */
                                *output += next_char - address;
                                *remaining -= next_char - address;

                                /* Each address needs a trailing semicolon. */
                                memcpy(*output, ";", 1);
                                *output += 1;
                                *remaining -= 1;
                        }
                }
                haystack = next_char;
        }
}

static void kvp_get_gateway(void *buffer, size_t buffer_len)
{
        static const char needle[] = "default ";
        FILE *f;
        void *output = buffer;
        char *line = NULL;
        size_t alloc_size = 0, remaining = buffer_len - 1;
        ssize_t num_chars;

        /* Show route information in a single line, for each address family */
        f = popen("ip --oneline -4 route show;ip --oneline -6 route show", "r");
        if (!f) {
                /* Convert buffer into C-String. */
                memcpy(output, "", 1);
                return;
        }
        while ((num_chars = getline(&line, &alloc_size, f)) > 0) {
                /* Skip short lines. */
                if (num_chars <= strlen(needle))
                        continue;
                /* Skip lines without default route. */
                if (memcmp(line, needle, strlen(needle)))
                        continue;
                /* Remove trailing newline to simplify further parsing. */
                if (line[num_chars - 1] == '\n')
                        line[num_chars - 1] = '\0';
                /* Search routes after match. */
                kvp_extract_routes(line + strlen(needle), &output, &remaining);
        }
        /* Convert buffer into C-String. */
        memcpy(output, "", 1);
        free(line);
        pclose(f);
}

static void kvp_get_ipconfig_info(char *if_name,
                                 struct hv_kvp_ipaddr_value *buffer)
{
        char cmd[512];
        char dhcp_info[128];
        char *p;
        FILE *file;

        kvp_get_gateway(buffer->gate_way, sizeof(buffer->gate_way));

        /*
         * Gather the DNS state.
         * Since there is no standard way to get this information
         * across various distributions of interest; we just invoke
         * an external script that needs to be ported across distros
         * of interest.
         *
         * Following is the expected format of the information from the script:
         *
         * ipaddr1 (nameserver1)
         * ipaddr2 (nameserver2)
         * .
         * .
         */

        sprintf(cmd, "exec %s %s", KVP_SCRIPTS_PATH "hv_get_dns_info", if_name);

        /*
         * Execute the command to gather DNS info.
         */
        kvp_process_ipconfig_file(cmd, (char *)buffer->dns_addr,
                                (MAX_IP_ADDR_SIZE * 2), INET_ADDRSTRLEN, 0);

        /*
         * Gather the DHCP state.
         * We will gather this state by invoking an external script.
         * The parameter to the script is the interface name.
         * Here is the expected output:
         *
         * Enabled: DHCP enabled.
         */

        sprintf(cmd, "exec %s %s", KVP_SCRIPTS_PATH "hv_get_dhcp_info", if_name);

        file = popen(cmd, "r");
        if (file == NULL)
                return;

        p = fgets(dhcp_info, sizeof(dhcp_info), file);
        if (p == NULL) {
                pclose(file);
                return;
        }

        if (!strncmp(p, "Enabled", 7))
                buffer->dhcp_enabled = 1;
        else
                buffer->dhcp_enabled = 0;

        pclose(file);
}


static unsigned int hweight32(unsigned int *w)
{
        unsigned int res = *w - ((*w >> 1) & 0x55555555);
        res = (res & 0x33333333) + ((res >> 2) & 0x33333333);
        res = (res + (res >> 4)) & 0x0F0F0F0F;
        res = res + (res >> 8);
        return (res + (res >> 16)) & 0x000000FF;
}

static int kvp_process_ip_address(void *addrp,
                                int family, char *buffer,
                                int length,  int *offset)
{
        struct sockaddr_in *addr;
        struct sockaddr_in6 *addr6;
        int addr_length;
        char tmp[50];
        const char *str;

        if (family == AF_INET) {
                addr = addrp;
                str = inet_ntop(family, &addr->sin_addr, tmp, 50);
                addr_length = INET_ADDRSTRLEN;
        } else {
                addr6 = addrp;
                str = inet_ntop(family, &addr6->sin6_addr.s6_addr, tmp, 50);
                addr_length = INET6_ADDRSTRLEN;
        }

        if ((length - *offset) < addr_length + 2)
                return HV_E_FAIL;
        if (str == NULL) {
                strcpy(buffer, "inet_ntop failed\n");
                return HV_E_FAIL;
        }
        if (*offset == 0)
                strcpy(buffer, tmp);
        else {
                strcat(buffer, ";");
                strcat(buffer, tmp);
        }

        *offset += strlen(str) + 1;

        return 0;
}

static int
kvp_get_ip_info(int family, char *if_name, int op,
                 void  *out_buffer, unsigned int length)
{
        struct ifaddrs *ifap;
        struct ifaddrs *curp;
        int offset = 0;
        int sn_offset = 0;
        int error = 0;
        char *buffer;
        struct hv_kvp_ipaddr_value *ip_buffer = NULL;
        char cidr_mask[5]; /* /xyz */
        int weight;
        int i;
        unsigned int *w;
        char *sn_str;
        struct sockaddr_in6 *addr6;

        if (op == KVP_OP_ENUMERATE) {
                buffer = out_buffer;
        } else {
                ip_buffer = out_buffer;
                buffer = (char *)ip_buffer->ip_addr;
                ip_buffer->addr_family = 0;
        }
        /*
         * On entry into this function, the buffer is capable of holding the
         * maximum key value.
         */

        if (getifaddrs(&ifap)) {
                strcpy(buffer, "getifaddrs failed\n");
                return HV_E_FAIL;
        }

        curp = ifap;
        while (curp != NULL) {
                if (curp->ifa_addr == NULL) {
                        curp = curp->ifa_next;
                        continue;
                }

                if ((if_name != NULL) &&
                        (strncmp(curp->ifa_name, if_name, strlen(if_name)))) {
                        /*
                         * We want info about a specific interface;
                         * just continue.
                         */
                        curp = curp->ifa_next;
                        continue;
                }

                /*
                 * We only support two address families: AF_INET and AF_INET6.
                 * If a family value of 0 is specified, we collect both
                 * supported address families; if not we gather info on
                 * the specified address family.
                 */
                if ((((family != 0) &&
                         (curp->ifa_addr->sa_family != family))) ||
                         (curp->ifa_flags & IFF_LOOPBACK)) {
                        curp = curp->ifa_next;
                        continue;
                }
                if ((curp->ifa_addr->sa_family != AF_INET) &&
                        (curp->ifa_addr->sa_family != AF_INET6)) {
                        curp = curp->ifa_next;
                        continue;
                }

                if (op == KVP_OP_GET_IP_INFO) {
                        /*
                         * Gather info other than the IP address.
                         * IP address info will be gathered later.
                         */
                        if (curp->ifa_addr->sa_family == AF_INET) {
                                ip_buffer->addr_family |= ADDR_FAMILY_IPV4;
                                /*
                                 * Get subnet info.
                                 */
                                error = kvp_process_ip_address(
                                                             curp->ifa_netmask,
                                                             AF_INET,
                                                             (char *)
                                                             ip_buffer->sub_net,
                                                             length,
                                                             &sn_offset);
                                if (error)
                                        goto gather_ipaddr;
                        } else {
                                ip_buffer->addr_family |= ADDR_FAMILY_IPV6;

                                /*
                                 * Get subnet info in CIDR format.
                                 */
                                weight = 0;
                                sn_str = (char *)ip_buffer->sub_net;
                                addr6 = (struct sockaddr_in6 *)
                                        curp->ifa_netmask;
                                w = addr6->sin6_addr.s6_addr32;

                                for (i = 0; i < 4; i++)
                                        weight += hweight32(&w[i]);

                                sprintf(cidr_mask, "/%d", weight);
                                if (length < sn_offset + strlen(cidr_mask) + 1)
                                        goto gather_ipaddr;

                                if (sn_offset == 0)
                                        strcpy(sn_str, cidr_mask);
                                else {
                                        strcat((char *)ip_buffer->sub_net, ";");
                                        strcat(sn_str, cidr_mask);
                                }
                                sn_offset += strlen(sn_str) + 1;
                        }

                        /*
                         * Collect other ip related configuration info.
                         */

                        kvp_get_ipconfig_info(if_name, ip_buffer);
                }

gather_ipaddr:
                error = kvp_process_ip_address(curp->ifa_addr,
                                                curp->ifa_addr->sa_family,
                                                buffer,
                                                length, &offset);
                if (error)
                        goto getaddr_done;

                curp = curp->ifa_next;
        }

getaddr_done:
        freeifaddrs(ifap);
        return error;
}

/*
 * Retrieve the IP given the MAC address.
 */
static int kvp_mac_to_ip(struct hv_kvp_ipaddr_value *kvp_ip_val)
{
        char *mac = (char *)kvp_ip_val->adapter_id;
        DIR *dir;
        struct dirent *entry;
        FILE    *file;
        char    *p, *x;
        char    *if_name = NULL;
        char    buf[256];
        char dev_id[PATH_MAX];
        unsigned int i;
        int error = HV_E_FAIL;

        dir = opendir(KVP_NET_DIR);
        if (dir == NULL)
                return HV_E_FAIL;

        while ((entry = readdir(dir)) != NULL) {
                /*
                 * Set the state for the next pass.
                 */
                snprintf(dev_id, sizeof(dev_id), "%s%s/address", KVP_NET_DIR,
                         entry->d_name);

                file = fopen(dev_id, "r");
                if (file == NULL)
                        continue;

                p = fgets(buf, sizeof(buf), file);
                fclose(file);
                if (!p)
                        continue;

                x = strchr(p, '\n');
                if (x)
                        *x = '\0';

                for (i = 0; i < strlen(p); i++)
                        p[i] = toupper(p[i]);

                if (strcmp(p, mac))
                        continue;

                /*
                 * Found the MAC match.
                 * A NIC (e.g. VF) matching the MAC, but without IP, is skipped.
                 */
                if_name = entry->d_name;
                if (!if_name)
                        continue;

                error = kvp_get_ip_info(0, if_name, KVP_OP_GET_IP_INFO,
                                        kvp_ip_val, MAX_IP_ADDR_SIZE * 2);

                if (!error && strlen((char *)kvp_ip_val->ip_addr))
                        break;
        }

        closedir(dir);
        return error;
}

static int expand_ipv6(char *addr, int type)
{
        int ret;
        struct in6_addr v6_addr;

        ret = inet_pton(AF_INET6, addr, &v6_addr);

        if (ret != 1) {
                if (type == NETMASK)
                        return 1;
                return 0;
        }

        sprintf(addr, "%02x%02x:%02x%02x:%02x%02x:%02x%02x:%02x%02x:"
                "%02x%02x:%02x%02x:%02x%02x",
                (int)v6_addr.s6_addr[0], (int)v6_addr.s6_addr[1],
                (int)v6_addr.s6_addr[2], (int)v6_addr.s6_addr[3],
                (int)v6_addr.s6_addr[4], (int)v6_addr.s6_addr[5],
                (int)v6_addr.s6_addr[6], (int)v6_addr.s6_addr[7],
                (int)v6_addr.s6_addr[8], (int)v6_addr.s6_addr[9],
                (int)v6_addr.s6_addr[10], (int)v6_addr.s6_addr[11],
                (int)v6_addr.s6_addr[12], (int)v6_addr.s6_addr[13],
                (int)v6_addr.s6_addr[14], (int)v6_addr.s6_addr[15]);

        return 1;

}

static int is_ipv4(char *addr)
{
        int ret;
        struct in_addr ipv4_addr;

        ret = inet_pton(AF_INET, addr, &ipv4_addr);

        if (ret == 1)
                return 1;
        return 0;
}

static int parse_ip_val_buffer(char *in_buf, int *offset,
                                char *out_buf, int out_len)
{
        char *x;
        char *start;

        /*
         * in_buf has sequence of characters that are separated by
         * the character ';'. The last sequence does not have the
         * terminating ";" character.
         */
        start = in_buf + *offset;

        x = strchr(start, ';');
        if (x)
                *x = 0;
        else
                x = start + strlen(start);

        if (strlen(start) != 0) {
                int i = 0;
                /*
                 * Get rid of leading spaces.
                 */
                while (start[i] == ' ')
                        i++;

                if ((x - start) <= out_len) {
                        strcpy(out_buf, (start + i));
                        *offset += (x - start) + 1;
                        return 1;
                }
        }
        return 0;
}

static int kvp_write_file(FILE *f, char *s1, char *s2, char *s3)
{
        int ret;

        ret = fprintf(f, "%s%s%s%s\n", s1, s2, "=", s3);

        if (ret < 0)
                return HV_E_FAIL;

        return 0;
}


static int process_ip_string(FILE *f, char *ip_string, int type)
{
        int error = 0;
        char addr[INET6_ADDRSTRLEN];
        int i = 0;
        int j = 0;
        char str[256];
        char sub_str[13];
        int offset = 0;

        memset(addr, 0, sizeof(addr));

        while (parse_ip_val_buffer(ip_string, &offset, addr,
                                        (MAX_IP_ADDR_SIZE * 2))) {

                sub_str[0] = 0;
                if (is_ipv4(addr)) {
                        switch (type) {
                        case IPADDR:
                                snprintf(str, sizeof(str), "%s", "IPADDR");
                                break;
                        case NETMASK:
                                snprintf(str, sizeof(str), "%s", "NETMASK");
                                break;
                        case GATEWAY:
                                snprintf(str, sizeof(str), "%s", "GATEWAY");
                                break;
                        case DNS:
                                snprintf(str, sizeof(str), "%s", "DNS");
                                break;
                        }

                        if (type == DNS) {
                                snprintf(sub_str, sizeof(sub_str), "%d", ++i);
                        } else if (type == GATEWAY && i == 0) {
                                ++i;
                        } else {
                                snprintf(sub_str, sizeof(sub_str), "%d", i++);
                        }


                } else if (expand_ipv6(addr, type)) {
                        switch (type) {
                        case IPADDR:
                                snprintf(str, sizeof(str), "%s", "IPV6ADDR");
                                break;
                        case NETMASK:
                                snprintf(str, sizeof(str), "%s", "IPV6NETMASK");
                                break;
                        case GATEWAY:
                                snprintf(str, sizeof(str), "%s",
                                        "IPV6_DEFAULTGW");
                                break;
                        case DNS:
                                snprintf(str, sizeof(str), "%s",  "DNS");
                                break;
                        }

                        if (type == DNS) {
                                snprintf(sub_str, sizeof(sub_str), "%d", ++i);
                        } else if (j == 0) {
                                ++j;
                        } else {
                                snprintf(sub_str, sizeof(sub_str), "_%d", j++);
                        }
                } else {
                        return  HV_INVALIDARG;
                }

                error = kvp_write_file(f, str, sub_str, addr);
                if (error)
                        return error;
                memset(addr, 0, sizeof(addr));
        }

        return 0;
}

int ip_version_check(const char *input_addr)
{
        struct in6_addr addr;

        if (inet_pton(AF_INET, input_addr, &addr))
                return IPV4;
        else if (inet_pton(AF_INET6, input_addr, &addr))
                return IPV6;

        return -EINVAL;
}

/*
 * Only IPv4 subnet strings needs to be converted to plen
 * For IPv6 the subnet is already privided in plen format
 */
static int kvp_subnet_to_plen(char *subnet_addr_str)
{
        int plen = 0;
        struct in_addr subnet_addr4;

        /*
         * Convert subnet address to binary representation
         */
        if (inet_pton(AF_INET, subnet_addr_str, &subnet_addr4) == 1) {
                uint32_t subnet_mask = ntohl(subnet_addr4.s_addr);

                while (subnet_mask & 0x80000000) {
                        plen++;
                        subnet_mask <<= 1;
                }
        } else {
                return -1;
        }

        return plen;
}

static int process_dns_gateway_nm(FILE *f, char *ip_string, int type,
                                  int ip_sec)
{
        char addr[INET6_ADDRSTRLEN], *output_str;
        int ip_offset = 0, error = 0, ip_ver;
        char *param_name;

        if (type == DNS)
                param_name = "dns";
        else if (type == GATEWAY)
                param_name = "gateway";
        else
                return -EINVAL;

        output_str = (char *)calloc(OUTSTR_BUF_SIZE, sizeof(char));
        if (!output_str)
                return -ENOMEM;

        while (1) {
                memset(addr, 0, sizeof(addr));

                if (!parse_ip_val_buffer(ip_string, &ip_offset, addr,
                                         (MAX_IP_ADDR_SIZE * 2)))
                        break;

                ip_ver = ip_version_check(addr);
                if (ip_ver < 0)
                        continue;

                if ((ip_ver == IPV4 && ip_sec == IPV4) ||
                    (ip_ver == IPV6 && ip_sec == IPV6)) {
                        /*
                         * do a bound check to avoid out-of bound writes
                         */
                        if ((OUTSTR_BUF_SIZE - strlen(output_str)) >
                            (strlen(addr) + 1)) {
                                strncat(output_str, addr,
                                        OUTSTR_BUF_SIZE -
                                        strlen(output_str) - 1);
                                strncat(output_str, ",",
                                        OUTSTR_BUF_SIZE -
                                        strlen(output_str) - 1);
                        }
                } else {
                        continue;
                }
        }

        if (strlen(output_str)) {
                /*
                 * This is to get rid of that extra comma character
                 * in the end of the string
                 */
                output_str[strlen(output_str) - 1] = '\0';
                error = fprintf(f, "%s=%s\n", param_name, output_str);
        }

        free(output_str);
        return error;
}

static int process_ip_string_nm(FILE *f, char *ip_string, char *subnet,
                                int ip_sec)
{
        char addr[INET6_ADDRSTRLEN];
        char subnet_addr[INET6_ADDRSTRLEN];
        int error = 0, i = 0;
        int ip_offset = 0, subnet_offset = 0;
        int plen, ip_ver;

        memset(addr, 0, sizeof(addr));
        memset(subnet_addr, 0, sizeof(subnet_addr));

        while (parse_ip_val_buffer(ip_string, &ip_offset, addr,
                                   (MAX_IP_ADDR_SIZE * 2)) &&
                                   parse_ip_val_buffer(subnet,
                                                       &subnet_offset,
                                                       subnet_addr,
                                                       (MAX_IP_ADDR_SIZE *
                                                        2))) {
                ip_ver = ip_version_check(addr);
                if (ip_ver < 0)
                        continue;

                if (ip_ver == IPV4 && ip_sec == IPV4)
                        plen = kvp_subnet_to_plen((char *)subnet_addr);
                else if (ip_ver == IPV6 && ip_sec == IPV6)
                        plen = atoi(subnet_addr);
                else
                        continue;

                if (plen < 0)
                        return plen;

                error = fprintf(f, "address%d=%s/%d\n", ++i, (char *)addr,
                                plen);
                if (error < 0)
                        return error;

                memset(addr, 0, sizeof(addr));
                memset(subnet_addr, 0, sizeof(subnet_addr));
        }

        return error;
}

static int kvp_set_ip_info(char *if_name, struct hv_kvp_ipaddr_value *new_val)
{
        int error = 0, ip_ver;
        char if_filename[PATH_MAX];
        char nm_filename[PATH_MAX];
        FILE *ifcfg_file, *nmfile;
        char cmd[PATH_MAX];
        char *mac_addr;
        int str_len;

        /*
         * Set the configuration for the specified interface with
         * the information provided. Since there is no standard
         * way to configure an interface, we will have an external
         * script that does the job of configuring the interface and
         * flushing the configuration.
         *
         * The parameters passed to this external script are:
         * 1. A configuration file that has the specified configuration.
         *
         * We will embed the name of the interface in the configuration
         * file: ifcfg-ethx (where ethx is the interface name).
         *
         * The information provided here may be more than what is needed
         * in a given distro to configure the interface and so are free
         * ignore information that may not be relevant.
         *
         * Here is the ifcfg format of the ip configuration file:
         *
         * HWADDR=macaddr
         * DEVICE=interface name
         * BOOTPROTO=<protocol> (where <protocol> is "dhcp" if DHCP is configured
         *                       or "none" if no boot-time protocol should be used)
         *
         * IPADDR0=ipaddr1
         * IPADDR1=ipaddr2
         * IPADDRx=ipaddry (where y = x + 1)
         *
         * NETMASK0=netmask1
         * NETMASKx=netmasky (where y = x + 1)
         *
         * GATEWAY=ipaddr1
         * GATEWAYx=ipaddry (where y = x + 1)
         *
         * DNSx=ipaddrx (where first DNS address is tagged as DNS1 etc)
         *
         * IPV6 addresses will be tagged as IPV6ADDR, IPV6 gateway will be
         * tagged as IPV6_DEFAULTGW and IPV6 NETMASK will be tagged as
         * IPV6NETMASK.
         *
         * Here is the keyfile format of the ip configuration file:
         *
         * [ethernet]
         * mac-address=macaddr
         * [connection]
         * interface-name=interface name
         *
         * [ipv4]
         * method=<protocol> (where <protocol> is "auto" if DHCP is configured
         *                       or "manual" if no boot-time protocol should be used)
         *
         * address1=ipaddr1/plen
         * address2=ipaddr2/plen
         *
         * gateway=gateway1;gateway2
         *
         * dns=dns1;dns2
         *
         * [ipv6]
         * address1=ipaddr1/plen
         * address2=ipaddr2/plen
         *
         * gateway=gateway1;gateway2
         *
         * dns=dns1;dns2
         *
         * The host can specify multiple ipv4 and ipv6 addresses to be
         * configured for the interface. Furthermore, the configuration
         * needs to be persistent. A subsequent GET call on the interface
         * is expected to return the configuration that is set via the SET
         * call.
         */

        /*
         * We are populating both ifcfg and nmconnection files
         */
        snprintf(if_filename, sizeof(if_filename), "%s%s%s", KVP_CONFIG_LOC,
                 "/ifcfg-", if_name);

        ifcfg_file = fopen(if_filename, "w");

        if (!ifcfg_file) {
                syslog(LOG_ERR, "Failed to open config file; error: %d %s",
                       errno, strerror(errno));
                return HV_E_FAIL;
        }

        snprintf(nm_filename, sizeof(nm_filename), "%s%s%s%s", KVP_CONFIG_LOC,
                 "/", if_name, ".nmconnection");

        nmfile = fopen(nm_filename, "w");

        if (!nmfile) {
                syslog(LOG_ERR, "Failed to open config file; error: %d %s",
                       errno, strerror(errno));
                fclose(ifcfg_file);
                return HV_E_FAIL;
        }

        /*
         * First write out the MAC address.
         */

        mac_addr = kvp_if_name_to_mac(if_name);
        if (mac_addr == NULL) {
                error = HV_E_FAIL;
                goto setval_error;
        }

        error = kvp_write_file(ifcfg_file, "HWADDR", "", mac_addr);
        if (error < 0)
                goto setmac_error;

        error = kvp_write_file(ifcfg_file, "DEVICE", "", if_name);
        if (error < 0)
                goto setmac_error;

        error = fprintf(nmfile, "\n[connection]\n");
        if (error < 0)
                goto setmac_error;

        error = kvp_write_file(nmfile, "interface-name", "", if_name);
        if (error)
                goto setmac_error;

        error = fprintf(nmfile, "\n[ethernet]\n");
        if (error < 0)
                goto setmac_error;

        error = kvp_write_file(nmfile, "mac-address", "", mac_addr);
        if (error)
                goto setmac_error;

        free(mac_addr);

        /*
         * The dhcp_enabled flag is only for IPv4. In the case the host only
         * injects an IPv6 address, the flag is true, but we still need to
         * proceed to parse and pass the IPv6 information to the
         * disto-specific script hv_set_ifconfig.
         */

        /*
         * First populate the ifcfg file format
         */
        if (new_val->dhcp_enabled) {
                error = kvp_write_file(ifcfg_file, "BOOTPROTO", "", "dhcp");
                if (error)
                        goto setval_error;
        } else {
                error = kvp_write_file(ifcfg_file, "BOOTPROTO", "", "none");
                if (error)
                        goto setval_error;
        }

        error = process_ip_string(ifcfg_file, (char *)new_val->ip_addr,
                                  IPADDR);
        if (error)
                goto setval_error;

        error = process_ip_string(ifcfg_file, (char *)new_val->sub_net,
                                  NETMASK);
        if (error)
                goto setval_error;

        error = process_ip_string(ifcfg_file, (char *)new_val->gate_way,
                                  GATEWAY);
        if (error)
                goto setval_error;

        error = process_ip_string(ifcfg_file, (char *)new_val->dns_addr, DNS);
        if (error)
                goto setval_error;

        /*
         * Now we populate the keyfile format
         *
         * The keyfile format expects the IPv6 and IPv4 configuration in
         * different sections. Therefore we iterate through the list twice,
         * once to populate the IPv4 section and the next time for IPv6
         */
        ip_ver = IPV4;
        do {
                if (ip_ver == IPV4) {
                        error = fprintf(nmfile, "\n[ipv4]\n");
                        if (error < 0)
                                goto setval_error;
                } else {
                        error = fprintf(nmfile, "\n[ipv6]\n");
                        if (error < 0)
                                goto setval_error;
                }

                /*
                 * Write the configuration for ipaddress, netmask, gateway and
                 * name services
                 */
                error = process_ip_string_nm(nmfile, (char *)new_val->ip_addr,
                                             (char *)new_val->sub_net,
                                             ip_ver);
                if (error < 0)
                        goto setval_error;

                /*
                 * As dhcp_enabled is only valid for ipv4, we do not set dhcp
                 * methods for ipv6 based on dhcp_enabled flag.
                 *
                 * For ipv4, set method to manual only when dhcp_enabled is
                 * false and specific ipv4 addresses are configured. If neither
                 * dhcp_enabled is true and no ipv4 addresses are configured,
                 * set method to 'disabled'.
                 *
                 * For ipv6, set method to manual when we configure ipv6
                 * addresses. Otherwise set method to 'auto' so that SLAAC from
                 * RA may be used.
                 */
                if (ip_ver == IPV4) {
                        if (new_val->dhcp_enabled) {
                                error = kvp_write_file(nmfile, "method", "",
                                                       "auto");
                                if (error < 0)
                                        goto setval_error;
                        } else if (error) {
                                error = kvp_write_file(nmfile, "method", "",
                                                       "manual");
                                if (error < 0)
                                        goto setval_error;
                        } else {
                                error = kvp_write_file(nmfile, "method", "",
                                                       "disabled");
                                if (error < 0)
                                        goto setval_error;
                        }
                } else if (ip_ver == IPV6) {
                        if (error) {
                                error = kvp_write_file(nmfile, "method", "",
                                                       "manual");
                                if (error < 0)
                                        goto setval_error;
                        } else {
                                error = kvp_write_file(nmfile, "method", "",
                                                       "auto");
                                if (error < 0)
                                        goto setval_error;
                        }
                }

                error = process_dns_gateway_nm(nmfile,
                                               (char *)new_val->gate_way,
                                               GATEWAY, ip_ver);
                if (error < 0)
                        goto setval_error;

                error = process_dns_gateway_nm(nmfile,
                                               (char *)new_val->dns_addr, DNS,
                                               ip_ver);
                if (error < 0)
                        goto setval_error;

                ip_ver++;
        } while (ip_ver < IP_TYPE_MAX);

        fclose(nmfile);
        fclose(ifcfg_file);

        /*
         * Now that we have populated the configuration file,
         * invoke the external script to do its magic.
         */

        str_len = snprintf(cmd, sizeof(cmd), "exec %s %s %s",
                           KVP_SCRIPTS_PATH "hv_set_ifconfig",
                           if_filename, nm_filename);
        /*
         * This is a little overcautious, but it's necessary to suppress some
         * false warnings from gcc 8.0.1.
         */
        if (str_len <= 0 || (unsigned int)str_len >= sizeof(cmd)) {
                syslog(LOG_ERR, "Cmd '%s' (len=%d) may be too long",
                       cmd, str_len);
                return HV_E_FAIL;
        }

        if (system(cmd)) {
                syslog(LOG_ERR, "Failed to execute cmd '%s'; error: %d %s",
                       cmd, errno, strerror(errno));
                return HV_E_FAIL;
        }
        return 0;
setmac_error:
        free(mac_addr);
setval_error:
        syslog(LOG_ERR, "Failed to write config file");
        fclose(ifcfg_file);
        fclose(nmfile);
        return error;
}


static void
kvp_get_domain_name(char *buffer, int length)
{
        struct addrinfo hints, *info ;
        int error = 0;

        gethostname(buffer, length);
        memset(&hints, 0, sizeof(hints));
        hints.ai_family = AF_INET; /*Get only ipv4 addrinfo. */
        hints.ai_socktype = SOCK_STREAM;
        hints.ai_flags = AI_CANONNAME;

        error = getaddrinfo(buffer, NULL, &hints, &info);
        if (error != 0) {
                snprintf(buffer, length, "getaddrinfo failed: 0x%x %s",
                        error, gai_strerror(error));
                return;
        }
        snprintf(buffer, length, "%s", info->ai_canonname);
        freeaddrinfo(info);
}

void print_usage(char *argv[])
{
        fprintf(stderr, "Usage: %s [options]\n"
                "Options are:\n"
                "  -n, --no-daemon        stay in foreground, don't daemonize\n"
                "  -d, --debug            Enable debug logs(syslog debug by default)\n"
                "  -h, --help             print this help\n", argv[0]);
}

int main(int argc, char *argv[])
{
        int kvp_fd = -1, len;
        int error;
        struct pollfd pfd;
        char    *p;
        struct hv_kvp_msg hv_msg[1];
        char    *key_value;
        char    *key_name;
        int     op;
        int     pool;
        char    *if_name;
        struct hv_kvp_ipaddr_value *kvp_ip_val;
        int daemonize = 1, long_index = 0, opt;

        static struct option long_options[] = {
                {"help",        no_argument,       0,  'h' },
                {"no-daemon",   no_argument,       0,  'n' },
                {"debug",       no_argument,       0,  'd' },
                {0,             0,                 0,  0   }
        };

        while ((opt = getopt_long(argc, argv, "hnd", long_options,
                                  &long_index)) != -1) {
                switch (opt) {
                case 'n':
                        daemonize = 0;
                        break;
                case 'h':
                        print_usage(argv);
                        exit(0);
                case 'd':
                        debug = 1;
                        break;
                default:
                        print_usage(argv);
                        exit(EXIT_FAILURE);
                }
        }

        if (daemonize && daemon(1, 0))
                return 1;

        openlog("KVP", 0, LOG_USER);
        syslog(LOG_INFO, "KVP starting; pid is:%d", getpid());

        /*
         * Retrieve OS release information.
         */
        kvp_get_os_info();
        /*
         * Cache Fully Qualified Domain Name because getaddrinfo takes an
         * unpredictable amount of time to finish.
         */
        kvp_get_domain_name(full_domain_name, sizeof(full_domain_name));

        if (debug)
                syslog(LOG_INFO, "Logging debug info in syslog(debug)");

        if (kvp_file_init()) {
                syslog(LOG_ERR, "Failed to initialize the pools");
                exit(EXIT_FAILURE);
        }

reopen_kvp_fd:
        if (kvp_fd != -1)
                close(kvp_fd);
        in_hand_shake = 1;
        kvp_fd = open("/dev/vmbus/hv_kvp", O_RDWR | O_CLOEXEC);

        if (kvp_fd < 0) {
                syslog(LOG_ERR, "open /dev/vmbus/hv_kvp failed; error: %d %s",
                       errno, strerror(errno));
                exit(EXIT_FAILURE);
        }

        /*
         * Register ourselves with the kernel.
         */
        hv_msg->kvp_hdr.operation = KVP_OP_REGISTER1;
        len = write(kvp_fd, hv_msg, sizeof(struct hv_kvp_msg));
        if (len != sizeof(struct hv_kvp_msg)) {
                syslog(LOG_ERR, "registration to kernel failed; error: %d %s",
                       errno, strerror(errno));
                close(kvp_fd);
                exit(EXIT_FAILURE);
        }

        pfd.fd = kvp_fd;

        while (1) {
                pfd.events = POLLIN;
                pfd.revents = 0;

                if (poll(&pfd, 1, -1) < 0) {
                        syslog(LOG_ERR, "poll failed; error: %d %s", errno, strerror(errno));
                        if (errno == EINVAL) {
                                close(kvp_fd);
                                exit(EXIT_FAILURE);
                        }
                        else
                                continue;
                }

                len = read(kvp_fd, hv_msg, sizeof(struct hv_kvp_msg));

                if (len != sizeof(struct hv_kvp_msg)) {
                        syslog(LOG_ERR, "read failed; error:%d %s",
                               errno, strerror(errno));
                        goto reopen_kvp_fd;
                }

                /*
                 * We will use the KVP header information to pass back
                 * the error from this daemon. So, first copy the state
                 * and set the error code to success.
                 */
                op = hv_msg->kvp_hdr.operation;
                pool = hv_msg->kvp_hdr.pool;
                hv_msg->error = HV_S_OK;

                if ((in_hand_shake) && (op == KVP_OP_REGISTER1)) {
                        /*
                         * Driver is registering with us; stash away the version
                         * information.
                         */
                        in_hand_shake = 0;
                        p = (char *)hv_msg->body.kvp_register.version;
                        lic_version = malloc(strlen(p) + 1);
                        if (lic_version) {
                                strcpy(lic_version, p);
                                syslog(LOG_INFO, "KVP LIC Version: %s",
                                       lic_version);
                        } else {
                                syslog(LOG_ERR, "malloc failed");
                        }
                        continue;
                }

                switch (op) {
                case KVP_OP_GET_IP_INFO:
                        kvp_ip_val = &hv_msg->body.kvp_ip_val;

                        error = kvp_mac_to_ip(kvp_ip_val);

                        if (error)
                                hv_msg->error = error;

                        break;

                case KVP_OP_SET_IP_INFO:
                        kvp_ip_val = &hv_msg->body.kvp_ip_val;
                        if_name = kvp_get_if_name(
                                        (char *)kvp_ip_val->adapter_id);
                        if (if_name == NULL) {
                                /*
                                 * We could not map the guid to an
                                 * interface name; return error.
                                 */
                                hv_msg->error = HV_GUID_NOTFOUND;
                                break;
                        }
                        error = kvp_set_ip_info(if_name, kvp_ip_val);
                        if (error)
                                hv_msg->error = error;

                        free(if_name);
                        break;

                case KVP_OP_SET:
                        if (kvp_key_add_or_modify(pool,
                                        hv_msg->body.kvp_set.data.key,
                                        hv_msg->body.kvp_set.data.key_size,
                                        hv_msg->body.kvp_set.data.value,
                                        hv_msg->body.kvp_set.data.value_size))
                                        hv_msg->error = HV_S_CONT;
                        break;

                case KVP_OP_GET:
                        if (kvp_get_value(pool,
                                        hv_msg->body.kvp_set.data.key,
                                        hv_msg->body.kvp_set.data.key_size,
                                        hv_msg->body.kvp_set.data.value,
                                        hv_msg->body.kvp_set.data.value_size))
                                        hv_msg->error = HV_S_CONT;
                        break;

                case KVP_OP_DELETE:
                        if (kvp_key_delete(pool,
                                        hv_msg->body.kvp_delete.key,
                                        hv_msg->body.kvp_delete.key_size))
                                        hv_msg->error = HV_S_CONT;
                        break;

                default:
                        break;
                }

                if (op != KVP_OP_ENUMERATE)
                        goto kvp_done;

                /*
                 * If the pool is KVP_POOL_AUTO, dynamically generate
                 * both the key and the value; if not read from the
                 * appropriate pool.
                 */
                if (pool != KVP_POOL_AUTO) {
                        if (kvp_pool_enumerate(pool,
                                        hv_msg->body.kvp_enum_data.index,
                                        hv_msg->body.kvp_enum_data.data.key,
                                        HV_KVP_EXCHANGE_MAX_KEY_SIZE,
                                        hv_msg->body.kvp_enum_data.data.value,
                                        HV_KVP_EXCHANGE_MAX_VALUE_SIZE))
                                        hv_msg->error = HV_S_CONT;
                        goto kvp_done;
                }

                key_name = (char *)hv_msg->body.kvp_enum_data.data.key;
                key_value = (char *)hv_msg->body.kvp_enum_data.data.value;

                switch (hv_msg->body.kvp_enum_data.index) {
                case FullyQualifiedDomainName:
                        strcpy(key_value, full_domain_name);
                        strcpy(key_name, "FullyQualifiedDomainName");
                        break;
                case IntegrationServicesVersion:
                        strcpy(key_name, "IntegrationServicesVersion");
                        strcpy(key_value, lic_version);
                        break;
                case NetworkAddressIPv4:
                        kvp_get_ip_info(AF_INET, NULL, KVP_OP_ENUMERATE,
                                key_value, HV_KVP_EXCHANGE_MAX_VALUE_SIZE);
                        strcpy(key_name, "NetworkAddressIPv4");
                        break;
                case NetworkAddressIPv6:
                        kvp_get_ip_info(AF_INET6, NULL, KVP_OP_ENUMERATE,
                                key_value, HV_KVP_EXCHANGE_MAX_VALUE_SIZE);
                        strcpy(key_name, "NetworkAddressIPv6");
                        break;
                case OSBuildNumber:
                        strcpy(key_value, os_build);
                        strcpy(key_name, "OSBuildNumber");
                        break;
                case OSName:
                        strcpy(key_value, os_name);
                        strcpy(key_name, "OSName");
                        break;
                case OSMajorVersion:
                        strcpy(key_value, os_major);
                        strcpy(key_name, "OSMajorVersion");
                        break;
                case OSMinorVersion:
                        strcpy(key_value, os_minor);
                        strcpy(key_name, "OSMinorVersion");
                        break;
                case OSVersion:
                        strcpy(key_value, os_version);
                        strcpy(key_name, "OSVersion");
                        break;
                case ProcessorArchitecture:
                        strcpy(key_value, processor_arch);
                        strcpy(key_name, "ProcessorArchitecture");
                        break;
                default:
                        hv_msg->error = HV_S_CONT;
                        break;
                }

                /*
                 * Send the value back to the kernel. Note: the write() may
                 * return an error due to hibernation; we can ignore the error
                 * by resetting the dev file, i.e. closing and re-opening it.
                 */
kvp_done:
                len = write(kvp_fd, hv_msg, sizeof(struct hv_kvp_msg));
                if (len != sizeof(struct hv_kvp_msg)) {
                        syslog(LOG_ERR, "write failed; error: %d %s", errno,
                               strerror(errno));
                        goto reopen_kvp_fd;
                }
        }

        close(kvp_fd);
        exit(0);
}