226 lines
7.0 KiB
C
226 lines
7.0 KiB
C
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/* A utility program originally written for the Linux OS SCSI subsystem.
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* Copyright (C) 2021 D. Gilbert
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2, or (at your option)
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* any later version.
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*
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* SPDX-License-Identifier: GPL-2.0-or-later
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*
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* This program is experimental. It allows the SG_CTL_FLAGM_SNAP_DEV
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* variant of ioctl(SG_SET_GET_EXTENDED) to be called. This assumes
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* a Linux sg driver whose version number > 4.00.30 .
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*/
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#include <unistd.h>
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#include <fcntl.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <stdarg.h>
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#include <stdbool.h>
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#include <string.h>
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#include <errno.h>
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#include <sys/ioctl.h>
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#include <sys/types.h>
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#include <sys/stat.h>
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#include <getopt.h>
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#ifdef HAVE_CONFIG_H
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#include "config.h"
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#endif
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#ifndef HAVE_LINUX_SG_V4_HDR
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/* Kernel uapi header contain __user decorations on user space pointers
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* to indicate they are unsafe in the kernel space. However glibc takes
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* all those __user decorations out from headers in /usr/include/linux .
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* So to stop compile errors when directly importing include/uapi/scsi/sg.h
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* undef __user before doing that include. */
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#define __user
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/* Want to block the original sg.h header from also being included. That
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* causes lots of multiple definition errors. This will only work if this
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* header is included _before_ the original sg.h header. */
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#define _SCSI_GENERIC_H /* original kernel header guard */
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#define _SCSI_SG_H /* glibc header guard */
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#include "uapi_sg.h" /* local copy of include/uapi/scsi/sg.h */
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#else
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#define __user
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#endif /* end of: ifndef HAVE_LINUX_SG_V4_HDR */
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#include "sg_lib.h"
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#include "sg_pr2serr.h"
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#define ME "sg_take_snap: "
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static const char * version_str = "1.01 20210403";
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#define SG_TAKE_MAX_DEVS 16
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static const char *dev_arr[SG_TAKE_MAX_DEVS];
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static int next_vacant_dev_idx = 0;
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static struct option long_options[] = {
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{"clear", no_argument, 0, 'c'},
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{"help", no_argument, 0, 'h'},
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{"verbose", no_argument, 0, 'v'},
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{"version", no_argument, 0, 'V'},
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{0, 0, 0, 0},
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};
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static void
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usage(void)
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{
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pr2serr("Usage: sg_take_snap [--clear] [--help] [--verbose] [--version] "
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"DEVICE*\n"
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" where:\n"
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" --clear|-c set 'clear_first' flag; otherwise appends\n"
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" --help|-h print usage information then exit\n"
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" --verbose|-v increase the level of verbosity\n"
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" --version|-V print version number then exit\n\n"
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"Use ioctl(SG_SET_GET_EXTENDED(SG_CTL_FLAGM_SNAP_DEV)) to take "
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"snap .\nThe output is placed in /sys/kernel/debug/scsi_generic/"
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"snapped and needs\nroot permissions to read. Requires a Linux "
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"sg driver version > 4.00.30 .\nOne or more DEVICEs can be "
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"given. Note: sending the ioctl to do this\ncreates some "
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"'noise' in the output\n"
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);
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}
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int main(int argc, char * argv[])
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{
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bool clear_first = false;
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int c, k, sg_fd, res;
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int ret = 0;
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int verbose = 0;
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const char * device_name = NULL;
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struct sg_extended_info sei;
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struct sg_extended_info * seip;
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while (1) {
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int option_index = 0;
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c = getopt_long(argc, argv, "chvV", long_options, &option_index);
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if (c == -1)
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break;
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switch (c) {
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case 'c':
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clear_first = true;
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break;
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case 'h':
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usage();
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return 0;
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case 'v':
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++verbose;
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break;
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case 'V':
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pr2serr(ME "version: %s\n", version_str);
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return 0;
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default:
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pr2serr("unrecognised option code 0x%x ??\n", c);
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usage();
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return SG_LIB_SYNTAX_ERROR;
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}
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}
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if (optind < argc) {
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for (; optind < argc; ++optind) {
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if (next_vacant_dev_idx < SG_TAKE_MAX_DEVS) {
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dev_arr[next_vacant_dev_idx] = argv[optind];
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++next_vacant_dev_idx;
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} else if (next_vacant_dev_idx == SG_TAKE_MAX_DEVS) {
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pr2serr("Maximum of %d DEVICEs on command line\n",
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next_vacant_dev_idx);
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usage();
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return SG_LIB_SYNTAX_ERROR;
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} else {
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pr2serr("something is wrong ...\n");
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return SG_LIB_SYNTAX_ERROR;
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}
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}
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}
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if (NULL == dev_arr[0]) {
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pr2serr("Need at least one DEVICE name. Use '--help' to see "
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"usage.\n");
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return SG_LIB_SYNTAX_ERROR;
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}
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for (k = 0; k < next_vacant_dev_idx; ++k) {
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device_name = dev_arr[k];
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sg_fd = open(device_name, O_RDWR | O_NONBLOCK);
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if (sg_fd < 0) {
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int err = errno;
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ret = sg_convert_errno(err);
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pr2serr(ME "open error: %s: ", device_name);
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perror("");
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sg_fd = -1;
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goto fini;
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}
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if (0 == k) {
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int t;
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res = ioctl(sg_fd, SG_GET_VERSION_NUM, &t);
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if ((res < 0) || (t < 30000)) {
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pr2serr("sg driver prior to 3.0.00\n");
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ret = SG_LIB_FILE_ERROR;
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goto fini;
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}
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if (verbose) {
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pr2serr("sg driver version: %d.%02d.%02d\n",
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t / 10000, (t % 10000) / 100, t % 100);
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}
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if (t < 40000) {
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pr2serr("Warning: sg driver prior to 4.0.00\n");
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ret = SG_LIB_FILE_ERROR;
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goto fini;
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} else if (t < 40045) {
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pr2serr("Warning: sg driver prior to 4.0.45\n");
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ret = SG_LIB_FILE_ERROR;
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goto fini;
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}
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}
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seip = &sei;
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memset(seip, 0, sizeof(*seip));
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seip->sei_wr_mask |= SG_SEIM_CTL_FLAGS;
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seip->sei_rd_mask |= SG_SEIM_CTL_FLAGS;
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seip->ctl_flags_wr_mask |= SG_CTL_FLAGM_SNAP_DEV;
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if (clear_first) /* ... else 0 (due to memset) --> append */
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seip->ctl_flags |= SG_CTL_FLAGM_SNAP_DEV;
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if (ioctl(sg_fd, SG_SET_GET_EXTENDED, seip) < 0) {
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pr2serr("ioctl(SG_SET_GET_EXTENDED(SG_CTL_FLAGM_SNAP_DEV)), %s "
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"failed errno=%d %s\n", device_name, errno,
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strerror(errno));
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ret = SG_LIB_FILE_ERROR;
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goto fini;
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}
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if (verbose)
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pr2serr("ioctl(%s, SG_SET_GET_EXTENDED(SG_CTL_FLAGM_SNAP_DEV)) "
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"ok\n", device_name);
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res = close(sg_fd);
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sg_fd = -1;
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if (res < 0) {
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pr2serr("close errno=%d on %s\n", errno, device_name);
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ret = res;
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goto fini;
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}
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}
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fini:
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if (sg_fd >= 0) {
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res = close(sg_fd);
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if (res < 0) {
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res = sg_convert_errno(errno);
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perror(ME "close error");
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if (0 == ret)
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ret = res;
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}
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}
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return (ret >= 0) ? ret : SG_LIB_CAT_OTHER;
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}
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