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https://github.com/ibm-s390-linux/s390-tools.git
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b94566048b
Introduce a write simulation operation, which doesn't write actual data and just updates the current position in the file. This allows to emulate block lists for files located on raw devices (not formatted with a file system). This is used by the next patches in the series to implement '--dry-run' zipl option for dumps of all types (not only ngdumps). Introduce a 'misc file descriptor', which allows to mark individual files as "opened in a simulation mode". Whenever bulding a bootmap file, use either real write, or write simulation depending on the mode set in the 'misc file descriptor'. Tested-by: Mikhail Zaslonko <zaslonko@linux.ibm.com> Reviewed-by: Mikhail Zaslonko <zaslonko@linux.ibm.com> Signed-off-by: Eduard Shishkin <edward6@linux.ibm.com> Signed-off-by: Jan Höppner <hoeppner@linux.ibm.com>
65 lines
1.4 KiB
C
65 lines
1.4 KiB
C
/*
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* zipl - zSeries Initial Program Loader tool
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*
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* Functions to manipulate with bootmap header
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*
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* Copyright IBM Corp. 2021
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*
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* s390-tools is free software; you can redistribute it and/or modify
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* it under the terms of the MIT license. See LICENSE for details.
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*/
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#include <errno.h>
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#include <string.h>
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#include "bootmap.h"
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#include "error.h"
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#include "misc.h"
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int bootmap_header_init(struct misc_fd *mfd)
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{
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struct bootmap_header bh = {
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.header_text =
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"zSeries bootmap file\n"
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"created by zIPL\n",
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.version = BOOTMAP_HEADER_VERSION
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};
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return misc_write_or_simulate(mfd, &bh, sizeof(bh));
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}
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static int bootmap_header_access(struct misc_fd *mfd, struct bootmap_header *bh, int read)
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{
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off_t cur_off;
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int ret;
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cur_off = lseek(mfd->fd, 0, SEEK_CUR);
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if (cur_off == -1) {
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error_reason(strerror(errno));
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return -1;
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}
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if (lseek(mfd->fd, 0, SEEK_SET) == -1) {
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error_reason(strerror(errno));
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ret = -1;
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goto out;
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}
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if (read)
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ret = misc_read(mfd->fd, bh, sizeof(*bh));
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else
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ret = misc_write_or_simulate(mfd, bh, sizeof(*bh));
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out:
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if (lseek(mfd->fd, cur_off, SEEK_SET) == -1)
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return -1;
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return ret;
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}
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int bootmap_header_read(struct misc_fd *mfd, struct bootmap_header *bh)
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{
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return bootmap_header_access(mfd, bh, 1);
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}
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int bootmap_header_write(struct misc_fd *mfd, struct bootmap_header *bh)
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{
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return bootmap_header_access(mfd, bh, 0);
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}
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