/*
 * 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 (c) 2010, Oracle and/or its affiliates. All rights reserved.
 */

/*
 * SES Log reader library
 *
 * This library is responsible for accessing the SES log at the target address,
 * formatting and returning any log entries found.
 *
 * The data will be returned in an nvlist_t structure allocated here.
 */

#include <assert.h>
#include <errno.h>
#include <fcntl.h>
#include <sys/param.h>
#include <libseslog.h>
#include <stdlib.h>
#include <string.h>
#include <sys/stat.h>
#include <unistd.h>
#include <dirent.h>
#include <sys/scsi/generic/commands.h>
#include <sys/scsi/generic/status.h>
#include <sys/scsi/impl/commands.h>

/*
 * open the device with given device name
 */
static int
open_device(const char *device_name)
{
        int oflags = O_NONBLOCK | O_RDWR;
        int fd;

        fd = open(device_name, oflags);
        if (fd < 0)
                fd = -errno;
        return (fd);
}

/*
 * Initialize scsi struct
 */
static void
construct_scsi_pt_obj(struct uscsi_cmd *uscsi)
{
        (void) memset(uscsi, 0, sizeof (struct uscsi_cmd));
        uscsi->uscsi_timeout = DEF_PT_TIMEOUT;
        uscsi->uscsi_flags = USCSI_READ | USCSI_ISOLATE | USCSI_RQENABLE;
}

/*
 * set control cdb of scsi structure
 */
static void
set_scsi_pt_cdb(struct uscsi_cmd *uscsi, const unsigned char *cdb,
    int cdb_len)
{
        uscsi->uscsi_cdb = (char *)cdb;
        uscsi->uscsi_cdblen = cdb_len;
}

/*
 * initialize sense data
 */
static void
set_scsi_pt_sense(struct uscsi_cmd *uscsi, unsigned char *sense,
    int max_sense_len)
{
        (void) memset(sense, 0, max_sense_len);
        uscsi->uscsi_rqbuf = (char *)sense;
        uscsi->uscsi_rqlen = max_sense_len;
}

/*
 * Initialize data going to device
 */
static void
set_scsi_pt_data_in(struct uscsi_cmd *uscsi, unsigned char *dxferp,
    int dxfer_len)
{
        if (dxfer_len > 0) {
                uscsi->uscsi_bufaddr = (char *)dxferp;
                uscsi->uscsi_buflen = dxfer_len;
                uscsi->uscsi_flags = USCSI_READ | USCSI_ISOLATE |
                    USCSI_RQENABLE;
        }
}

/*
 * Executes SCSI command(or at least forwards it to lower layers).
 */
static int
do_scsi_pt(struct uscsi_cmd *uscsi, int fd, int time_secs)
{
        if (time_secs > 0)
                uscsi->uscsi_timeout = time_secs;

        if (ioctl(fd, USCSICMD, uscsi)) {
                /* Took an error */
                return (errno);
        }
        return (0);
}


/*
 * Read log from device
 * Invokes a SCSI LOG SENSE command.
 * Return:
 * 0 -> success
 * SG_LIB_CAT_INVALID_OP -> Log Sense not supported,
 * SG_LIB_CAT_ILLEGAL_REQ -> bad field in cdb,
 * SG_LIB_CAT_NOT_READY -> device not ready,
 * -1 -> other failure
 */

static int
read_log(int sg_fd, unsigned char *resp, int mx_resp_len)
{
        int res, ret;
        unsigned char logsCmdBlk[CDB_GROUP1] =
            {SCMD_LOG_SENSE_G1, 0, 0, 0, 0, 0, 0, 0, 0, 0};
        unsigned char sense_b[SENSE_BUFF_LEN];
        struct uscsi_cmd uscsi;

        if (mx_resp_len > 0xffff) {
                return (-1);
        }
        logsCmdBlk[1] = 0;
        /* pc = 1, pg_code = 0x7 (logs page) */
        /* (((pc << 6) & 0xc0) | (pg_code & 0x3f)) = 0x47; */
        logsCmdBlk[2] = 0x47;
        /* pc = 1 current values */
        logsCmdBlk[3] = 0; /* No subpage code */
        logsCmdBlk[5] = 0; /* Want all logs starting from 0 */
        logsCmdBlk[6] = 0;
        logsCmdBlk[7] = (unsigned char) ((mx_resp_len >> 8) & 0xff);
        logsCmdBlk[8] = (unsigned char) (mx_resp_len & 0xff);

        construct_scsi_pt_obj(&uscsi);

        set_scsi_pt_cdb(&uscsi, logsCmdBlk, sizeof (logsCmdBlk));
        set_scsi_pt_sense(&uscsi, sense_b, sizeof (sense_b));
        set_scsi_pt_data_in(&uscsi, resp, mx_resp_len);
        res = do_scsi_pt(&uscsi, sg_fd, DEF_PT_TIMEOUT);
        if (res) {
                ret = res;
        } else {
                ret = uscsi.uscsi_status;
        }
        return (ret);
}

/*
 * Save the logs by walking through the entries in the response buffer.
 *
 * resp buffer looks like:
 *
 * +=====-========-========-========-========-========-========-========-=====+
 * |  Bit|   7    |   6    |   5    |   4    |   3    |   2    |   1    |   0 |
 * |Byte |        |        |        |        |        |        |        |     |
 * |=====+====================================================================|
 * | 0   |  reserved       |     page code                                    |
 * |-----+--------------------------------------------------------------------|
 * | 1   |                   Reserved                                         |
 * |-----+--------------------------------------------------------------------|
 * | 2   |(MSB)                           Page Length(n-3)                    |
 * | --  |                                                                    |
 * | 3   |                                                            (LSB)   |
 * |-----+--------------------------------------------------------------------|
 * | 4   |                           Log Parameter (First)(Length X)          |
 * | --  |                                                                    |
 * | x+3 |                                                                    |
 * |-----+--------------------------------------------------------------------|
 * |n-y+1|                           Log Parameter (Last)(Length y)           |
 * | --  |                                                                    |
 * | n   |                                                                    |
 * +==========================================================================+
 *
 * Log parameter field looks like:
 *
 * +=====-========-========-========-========-========-========-========-=====+
 * |  Bit|   7    |   6    |   5    |   4    |   3    |   2    |   1    |   0 |
 * |Byte |        |        |        |        |        |        |        |     |
 * |=====+====================================================================|
 * | 0   |(MSB)                           Parameter Code                      |
 * | --  |                                                                    |
 * | 1   |                                                            (LSB)   |
 * |-----+--------------------------------------------------------------------|
 * | 2   | DU     |  DS    |  TSD    | ETC   |         TMC     |  LBIN  | LP  |
 * |-----+--------------------------------------------------------------------|
 * | 3   |                          Parameter Length(n-3)                     |
 * |-----+--------------------------------------------------------------------|
 * | 4   |                           Parameter Values                         |
 * | --  |                                                                    |
 * | n   |                                                                    |
 * |-----+--------------------------------------------------------------------|
 */

static int
save_logs(unsigned char *resp, ses_log_call_t *data)
{
        int k;
        int param_code;         /* Parameter code */
        int param_len = 0;      /* Paramter length */
        unsigned char *log_param_ptr;   /* Log parameter pointer */
        unsigned char *log_str_ptr; /* ptr to ascii str returend by expander */

        char log_code[ENTRY_MAX_SIZE];
        char log_level[ENTRY_MAX_SIZE];
        nvlist_t *entry;
        char entry_num[15];
        int match_found = 0;
        char save_buffer[MAX_LOG_ENTRY_SZ];
        char entry_added = 0;
        int all_log_data_len;

        /*
         * Bytes 2 and 3 of response buffer contain the page length of
         * the log entries returned.
         */
        all_log_data_len = SCSI_READ16(&resp[2]);

        /*
         * Initialize log parameter pointer to point to first log entry.
         * The resp includes 4 bytes of header info and then log entries
         */
        log_param_ptr = &resp[0] + 4;

        /*
         * If multiple heads are reading the logs, it is possible that we
         * could be re-reading some of the same log entries plus some
         * new additional entries. Check to see if any entries in this read
         * contain the same log entry as the last entry we read last time.
         */
        if (strlen(data->last_log_entry) == SES_LOG_VALID_LOG_SIZE) {
                /*
                 * We have a valid log entry from a previous read log
                 * operation.
                 */


                /*
                 * Start walking each log entry in response buffer looking for
                 * a duplicate entry.
                 */
                for (k = 0; k < all_log_data_len; k += param_len) {
                        /*
                         * Calculate log entry length
                         * Log param ptr [3] contains the log length minus the
                         * header info which is 4 bytes so add that in.
                         */
                        param_len = log_param_ptr[3] + 4;

                        if (param_len <= 4) {
                                /*
                                 * Only header information in this entry
                                 * process next log entry
                                 */
                                log_param_ptr += param_len;
                                continue;
                        }


                        /*
                         * initialize log_str_ptr to point to string info
                         * returned by expander
                         * first 4 bytes of log parameter contains
                         * 2 bytes of parameter code, 1 byte of Control data
                         * and 1 byte for parameter length. Log string begins
                         * after that so add 4 to log param ptr.
                         */
                        log_str_ptr = log_param_ptr + 4;

                        /*
                         * Check to see if this is the
                         * same line
                         */
                        if (strncmp((char *)log_str_ptr, data->last_log_entry,
                            SES_LOG_VALID_LOG_SIZE) == 0) {
                                /* Found an exact match */
                                log_param_ptr += param_len;
                                k += param_len;
                                match_found = 1;
                                break;
                        }
                        log_param_ptr += param_len;
                }
        }
        if (!match_found) {
                log_param_ptr = &resp[0] + 4;
                k = 0;
        }
        if (k == all_log_data_len) {
                /*
                 * Either there was no log data or we have
                 * already read these log entries.
                 * Just return.
                 */
                return (0);
        }

        /* Grab memory to return logs with */
        if (nvlist_alloc(&data->log_data, NV_UNIQUE_NAME, 0) != 0) {
                /* Couldn't alloc memory for nvlist */
                return (SES_LOG_FAILED_NVLIST_CREATE);
        }

        (void) memset(log_code,         0, sizeof (log_code));
        (void) memset(save_buffer,      0, sizeof (save_buffer));
        (void) memset(log_level,        0, sizeof (log_level));

        /*
         * Start saving new log entries
         * Walk the log data adding any new entries
         */

        for (; k < all_log_data_len; k += param_len) {
                /*
                 * Calculate log entry length
                 * Log ptr [3] contains the log length minus the header info
                 * which is 4 bytes so add that in
                 */
                param_len = log_param_ptr[3] + 4;

                if (param_len <= 4) {
                        /* Only header information in this entry */
                        /* process next log entry */
                        log_param_ptr += param_len;
                        continue;
                }

                /*
                 * initialize log_str_ptr to point to string info of the log
                 * entry. First 4 bytes of log entry contains param code,
                 * control byte, and length. Log string starts after that.
                 */
                log_str_ptr = log_param_ptr + 4;

                /*
                 * Format of log str is as follows
                 * "%8x %8x %8x %8x %8x %8x %8x %8x",
                 * log_entry.log_word0, log_entry.ts_u, log_entry.ts_l,
                 * log_entry.seq_num, log_entry.log_code, log_entry.log_word2,
                 * log_entry.log_word3, log_entry.log_word4
                 * following example has extra spaces removed to fit in 80 char
                 * 40004 0 42d5f5fe 185b 630002 fd0800 50800207 e482813
                 */

                (void) strncpy(save_buffer,
                    (const char *)log_str_ptr,
                    SES_LOG_VALID_LOG_SIZE);

                (void) strncpy(log_code,
                    (const char *)log_str_ptr+SES_LOG_CODE_START,
                    SES_LOG_SPECIFIC_ENTRY_SIZE);

                (void) strncpy(log_level,
                    (const char *) log_str_ptr +
                    SES_LOG_LEVEL_START, 1);


                /* Add this entry to the nvlist log data */
                if (nvlist_alloc(&entry, NV_UNIQUE_NAME, 0) != 0) {
                        /* Couldn't alloc space, return error */
                        return (SES_LOG_FAILED_NV_UNIQUE);
                }


                if (nvlist_add_string(entry, ENTRY_LOG, save_buffer) != 0) {
                        /* Error adding string, return error */
                        nvlist_free(entry);
                        return (SES_LOG_FAILED_NV_LOG);
                }

                if (nvlist_add_string(entry, ENTRY_CODE, log_code) != 0) {
                        /* Error adding string, return error */
                        nvlist_free(entry);
                        return (SES_LOG_FAILED_NV_CODE);
                }
                if (nvlist_add_string(entry, ENTRY_SEVERITY, log_level) != 0) {
                        /* Error adding srtring, return error */
                        nvlist_free(entry);
                        return (SES_LOG_FAILED_NV_SEV);
                }

                param_code = SCSI_READ16(&log_param_ptr[0]);

                (void) snprintf(entry_num, sizeof (entry_num),
                    "%s%d", ENTRY_PREFIX, param_code);

                if (nvlist_add_nvlist(data->log_data, entry_num, entry) != 0) {
                        /* Error adding nvlist, return error */
                        nvlist_free(entry);
                        return (SES_LOG_FAILED_NV_ENTRY);
                }
                nvlist_free(entry);

                entry_added = 1;
                (data->number_log_entries)++;

                log_param_ptr += param_len;

        }
        if (entry_added) {
                /* Update the last log entry string with last one read */
                (void) strncpy(data->last_log_entry, save_buffer, MAXNAMELEN);
        }
        return (0);
}



/* Setup struct to send command to device */
static void
set_scsi_pt_data_out(struct uscsi_cmd *uscsi, const unsigned char *dxferp,
    int dxfer_len)
{
        if (dxfer_len > 0) {
                uscsi->uscsi_bufaddr = (char *)dxferp;
                uscsi->uscsi_buflen = dxfer_len;
                uscsi->uscsi_flags = USCSI_WRITE | USCSI_ISOLATE |
                    USCSI_RQENABLE;
        }
}

/*
 * Invokes a SCSI MODE SENSE(10) command.
 * Return:
 * 0 for success
 * SG_LIB_CAT_INVALID_OP -> invalid opcode
 * SG_LIB_CAT_ILLEGAL_REQ -> bad field in cdb
 * SG_LIB_CAT_NOT_READY -> device not ready
 * -1 -> other failure
 */

static int
sg_ll_mode_sense10(int sg_fd, void * resp, int mx_resp_len)
{
        int res, ret;
        unsigned char modesCmdBlk[MODE_SENSE10_CMDLEN] =
            {SCMD_MODE_SENSE_G1, 0, 0, 0, 0, 0, 0, 0, 0, 0};
        unsigned char sense_b[SENSE_BUFF_LEN];
        struct uscsi_cmd uscsi;

        modesCmdBlk[1] = 0;
        modesCmdBlk[2] = 0; /* page code 0 vendor specific */
        modesCmdBlk[3] = 0;
        modesCmdBlk[7] = (unsigned char) ((mx_resp_len >> 8) & 0xff);
        modesCmdBlk[8] = (unsigned char) (mx_resp_len & 0xff);

        construct_scsi_pt_obj(&uscsi);
        set_scsi_pt_cdb(&uscsi, modesCmdBlk, sizeof (modesCmdBlk));
        set_scsi_pt_sense(&uscsi, sense_b, sizeof (sense_b));
        set_scsi_pt_data_in(&uscsi, (unsigned char *) resp, mx_resp_len);
        res = do_scsi_pt(&uscsi, sg_fd, DEF_PT_TIMEOUT);
        if (res) {
                ret = res;
        } else {
                ret = uscsi.uscsi_status;
        }
        return (ret);
}

/*
 * Invokes a SCSI MODE SELECT(10) command.
 * Return:
 * 0 for success.
 * SG_LIB_CAT_INVALID_OP for invalid opcode
 * SG_LIB_CAT_ILLEGAL_REQ -> bad field in cdb,
 * SG_LIB_CAT_NOT_READY -> device not ready,
 * -1 -> other failure
 */
static int
sg_ll_mode_select10(int sg_fd, void * paramp, int param_len)
{
        int res, ret;
        unsigned char modesCmdBlk[MODE_SELECT10_CMDLEN] =
            {SCMD_MODE_SELECT_G1, 0, 0, 0, 0, 0, 0, 0, 0, 0};
        unsigned char sense_b[SENSE_BUFF_LEN];
        struct uscsi_cmd uscsi;


        modesCmdBlk[1] = 0;
        /*
         * modesCmdBlk 2 equal 0 PC 0 return current page code 0 return
         * vendor specific
         */

        modesCmdBlk[7] = (unsigned char)((param_len >> 8) & 0xff);
        modesCmdBlk[8] = (unsigned char)(param_len & 0xff);

        construct_scsi_pt_obj(&uscsi);

        set_scsi_pt_cdb(&uscsi, modesCmdBlk, sizeof (modesCmdBlk));
        set_scsi_pt_sense(&uscsi, sense_b, sizeof (sense_b));
        set_scsi_pt_data_out(&uscsi, (unsigned char *) paramp, param_len);
        res = do_scsi_pt(&uscsi, sg_fd, DEF_PT_TIMEOUT);
        if (res) {
                ret = res;
        } else {
                ret = uscsi.uscsi_status;
        }
        return (ret);
}



/*
 * MODE SENSE 10 commands yield a response that has block descriptors followed
 * by mode pages. In most cases users are interested in the first mode page.
 * This function returns the(byte) offset of the start of the first mode page.
 * Returns >= 0 is successful or -1 if failure. If there is a failure
 * a message is written to err_buff.
 */

/*
 * return data looks like:
 * Table 92 - Mode parameter header(10)
 * Bit
 * Byte
 *      7       6       5       4       3       2       1       0
 *      ----------------------------------------------------------
 * 0    MSB Data length
 * 1    LSB Data length
 *      ----------------------------------------------------------
 * 2    Medium type
 *      ----------------------------------------------------------
 * 3    Device-specific parameter
 *      ----------------------------------------------------------
 * 4    Reserved
 *      ----------------------------------------------------------
 * 5    Reserved
 *      ----------------------------------------------------------
 * 6    MSB block descriptor length
 * 7    LSB block descriptor length
 *      ----------------------------------------------------------
 *      block desciptors....
 *      -----------------------
 *      mode sense page:
 *      0 : ps Reserved : page Code
 *      1 : Page Length(n-1)
 *      2-N  Mode parameters
 */
static int
sg_mode_page_offset(const unsigned char *resp, int resp_len)
{
        int bd_len;
        int calc_len;
        int offset;

        if ((NULL == resp) || (resp_len < 8)) {
                /* Too short of a response buffer */
                return (-1);
        }

        calc_len = (resp[0] << 8) + resp[1] + 2;
        bd_len = (resp[6] << 8) + resp[7];

        /* LongLBA doesn't change this calculation */
        offset = bd_len + MODE10_RESP_HDR_LEN;

        if ((offset + 2) > resp_len) {
                /* Given response length to small */
                offset = -1;
        } else if ((offset + 2) > calc_len) {
                /* Calculated response length too small */
                offset = -1;
        }
        return (offset);
}

/*
 * Clear logs
 */
static int
clear_log(int sg_fd, ses_log_call_t *data)
{

        int res, alloc_len, off;
        int md_len;
        int read_in_len = 0;
        unsigned char ref_md[MAX_ALLOC_LEN];
        struct log_clear_control_struct clear_data;
        long myhostid;
        int error = 0;
        long poll_time;
        char seq_num_str[10];
        unsigned long seq_num = 0;

        (void) memset(&clear_data, 0, sizeof (clear_data));

        clear_data.pageControls = 0x40;
        clear_data.subpage_code = 0;
        clear_data.page_lengthLower = 0x16;

        myhostid = gethostid();
        /* 0 -> 11 are memset to 0 */
        clear_data.host_id[12] = (myhostid & 0xff000000) >> 24;
        clear_data.host_id[13] = (myhostid & 0xff0000) >> 16;
        clear_data.host_id[14] = (myhostid & 0xff00) >> 8;
        clear_data.host_id[15] = myhostid & 0xff;

        /*
         * convert nanosecond time to seconds
         */
        poll_time = data->poll_time / 1000000000;
        /* Add 5 minutes to poll time to allow for data retrieval time */
        poll_time = poll_time + 300;
        clear_data.timeout[0] = (poll_time & 0xff00) >> 8;
        clear_data.timeout[1] = poll_time & 0xff;

        /*
         * retrieve the last read sequence number from the last
         * log entry read.
         */
        if (strlen(data->last_log_entry) == SES_LOG_VALID_LOG_SIZE) {
                /*
                 * We have a valid log entry from a previous read log
                 * operation.
                 */
                (void) strncpy(seq_num_str,
                    (const char *) data->last_log_entry +
                    SES_LOG_SEQ_NUM_START, 8);
                seq_num = strtoul(seq_num_str, 0, 16);
        }
        clear_data.seq_clear[0] = (seq_num & 0xff000000) >> 24;
        clear_data.seq_clear[1] = (seq_num & 0xff0000) >> 16;
        clear_data.seq_clear[2] = (seq_num & 0xff00) >> 8;
        clear_data.seq_clear[3] = (seq_num & 0xff);

        read_in_len = sizeof (clear_data);


        /* do MODE SENSE to fetch current values */
        (void) memset(ref_md, 0, MAX_ALLOC_LEN);
        alloc_len = MAX_ALLOC_LEN;


        res = sg_ll_mode_sense10(sg_fd, ref_md, alloc_len);
        if (0 != res) {
                /* Error during mode sense */
                error = SES_LOG_FAILED_MODE_SENSE;
                return (error);
        }

        /* Setup mode Select to clear logs */
        off = sg_mode_page_offset(ref_md, alloc_len);
        if (off < 0) {
                /* Mode page offset error */
                error =  SES_LOG_FAILED_MODE_SENSE_OFFSET;
                return (error);
        }
        md_len = (ref_md[0] << 8) + ref_md[1] + 2;

        ref_md[0] = 0;
        ref_md[1] = 0;

        if (md_len > alloc_len) {
                /* Data length to large */
                error = SES_LOG_FAILED_BAD_DATA_LEN;
                return (error);
        }

        if ((md_len - off) != read_in_len) {
                /* Content length not correct */
                error = SES_LOG_FAILED_BAD_CONTENT_LEN;
                return (error);
        }

        if ((clear_data.pageControls & 0x40) != (ref_md[off] & 0x40)) {
                /* reference model doesn't have use subpage format bit set */
                /* Even though it should have */
                /* don't send the command */
                error = SES_LOG_FAILED_FORMAT_PAGE_ERR;
                return (error);
        }

        (void) memcpy(ref_md + off, (const void *) &clear_data,
            sizeof (clear_data));

        res = sg_ll_mode_select10(sg_fd, ref_md, md_len);
        if (res != 0) {
                error = SES_LOG_FAILED_MODE_SELECT;
                return (error);
        }

        return (error);
}
/*
 * Gather data from given device.
 */
static int
gather_data(char *device_name, ses_log_call_t *data)
{
        int sg_fd;
        int resp_len, res;
        unsigned char rsp_buff[MAX_ALLOC_LEN];
        int error;

        /* Open device */
        if ((sg_fd = open_device(device_name)) < 0) {
                /* Failed to open device */
                return (SES_LOG_FAILED_TO_OPEN_DEVICE);
        }

        /* Read the logs */
        (void) memset(rsp_buff, 0, sizeof (rsp_buff));
        resp_len = 0x8000; /* Maximum size available to read */
        res = read_log(sg_fd, rsp_buff, resp_len);

        if (res != 0) {
                /* Some sort of Error during read of logs */
                (void) close(sg_fd);
                return (SES_LOG_FAILED_TO_READ_DEVICE);
        }

        /* Save the logs */
        error = save_logs(rsp_buff, data);
        if (error != 0) {
                (void) close(sg_fd);
                return (error);
        }
        /* Clear the logs */
        error = clear_log(sg_fd, data);

        (void) close(sg_fd);

        return (error);
}

/*
 * Access the SES target identified by the indicated path.  Read the logs
 * and return them in a nvlist.
 */
int
access_ses_log(ses_log_call_t *data)
{
        char real_path[MAXPATHLEN];
        struct stat buffer;
        int error;

        /* Initialize return data */
        data->log_data = NULL;
        data->number_log_entries = 0;

        if (*data->target_path == '\0') {
                /* empty target path, return error */
                return (SES_LOG_FAILED_NULL_TARGET_PATH);
        }

        /* Try to find a valid path */
        (void) snprintf(real_path, sizeof (real_path), "/devices%s:ses",
            data->target_path);

        if (stat(real_path, &buffer) != 0) {

                (void) snprintf(real_path, sizeof (real_path), "/devices%s:0",
                    data->target_path);
                if (stat(real_path, &buffer) != 0) {
                        /* Couldn't find a path that exists */
                        return (SES_LOG_FAILED_BAD_TARGET_PATH);
                }
        }

        error = gather_data(real_path, data);

        /* Update the size of log entries being returned */
        data->size_of_log_entries =
            data->number_log_entries * SES_LOG_VALID_LOG_SIZE;

        return (error);
}