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eaa2ef6ba4
This patch prevents code duplication in vmcp related programs. Some applications such as vmur, vmcp, and lsqeth use z/VM CP commands to query information. Each program uses its own defines and code. Supply a library and common header file to use common code. Signed-off-by: Thomas Richter <tmricht@linux.vnet.ibm.com> Reviewed-by: Hendrik Brueckner <brueckner@linux.vnet.ibm.com> Reviewed-by: Jan Höppner <hoeppner@linux.vnet.ibm.com> Signed-off-by: Jan Höppner <hoeppner@linux.ibm.com>
135 lines
3.5 KiB
C
135 lines
3.5 KiB
C
/*
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* vmcp - z/VM CP function library
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*
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* Copyright IBM Corp. 2018
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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 <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <unistd.h>
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#include <fcntl.h>
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#include <errno.h>
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#include <sys/ioctl.h>
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#include "lib/util_libc.h"
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#include "lib/vmcp.h"
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#define VMCP_DEVICE_NODE "/dev/vmcp"
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#define VMCP_GETSIZE _IOR(0x10, 3, int)
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#define VMCP_SETBUF _IOW(0x10, 2, int)
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#define VMCP_GETCODE _IOR(0x10, 1, int)
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/*
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* Read at most COUNT bytes from FD into memory at location BUF.
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* Return number of bytes read on success, -1 on error.
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*/
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static ssize_t read_buffer(int fd, char *buf, ssize_t count)
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{
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ssize_t ret, done;
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for (done = 0; done < (ssize_t)count; done += ret) {
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ret = read(fd, &buf[done], count - done);
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if (ret == -1 && errno == EINTR)
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continue;
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if (ret == -1)
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return -1;
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if (ret == 0)
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break;
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}
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return done;
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}
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/**
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* Submit a command to z/VM CP and return the response, the size in bytes
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* of the response and CP command response code.
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*
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* The member response contains the response from CP. It is a pointer
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* to a malloc'ed buffer which must be freed by the caller when the return
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* code is zero or VMCP_ERR_TOOSMALL.
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*
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* @param[in,out] cmd Pointer to struct vmcp_parm.
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* @param[in] cpcmd Pointer to CP command string.
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* @param[in] do_upper If true convert cpcmd string to upper case.
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* @param[out] cprc Return code of the CP command.
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* @param[out] response Return buffer, has been allocated via malloc()
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* must be freed by caller, see below.
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* @param[out] response_size Size of the response in bytes, can be larger
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* than buffer_size.
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*
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* @returns Zero on success or a negative error number on failure.
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* @retval VMCP_SUCCESS Success valid members: cprc, response,
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* response_size
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* @retval VMCP_ERR_OPEN Error opening VMCP device, valid members: none
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* @retval VMCP_ERR_SETBUF Error setting buffer, valid members: none
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* @retval VMCP_ERR_GETCODE Error getting cp exit code, valid members: none
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* @retval VMCP_ERR_WRITE Error write CP command, valid members: none
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* @retval VMCP_ERR_GETSIZE Error reading response size,
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* valid members: cprc
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* @retval VMCP_ERR_READ Error reading resp
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* @retval VMCP_ERR_TOOSMALL Error response buffer too small, response
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* truncated, valid members: cprc, response,
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* response_size
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*/
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int vmcp(struct vmcp_parm *cmd)
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{
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int rc = VMCP_SUCCESS, fd, len;
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char *cpcmd;
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cmd->response = NULL;
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cmd->response_size = 0;
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cmd->cprc = 0;
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fd = open(VMCP_DEVICE_NODE, O_RDWR);
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if (fd == -1)
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return VMCP_ERR_OPEN;
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cpcmd = util_strdup(cmd->cpcmd); /* Exits on failure */
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if (cmd->do_upper)
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util_str_toupper(cpcmd);
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if (ioctl(fd, VMCP_SETBUF, &cmd->buffer_size) == -1) {
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rc = VMCP_ERR_SETBUF;
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goto fail;
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}
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if (write(fd, cpcmd, strlen(cpcmd)) == -1) {
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rc = VMCP_ERR_WRITE;
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goto fail;
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}
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if (ioctl(fd, VMCP_GETCODE, &cmd->cprc) == -1) {
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rc = VMCP_ERR_GETCODE;
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goto fail;
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}
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if (ioctl(fd, VMCP_GETSIZE, &cmd->response_size) == -1) {
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rc = VMCP_ERR_GETSIZE;
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goto fail;
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}
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if (cmd->response_size <= cmd->buffer_size) {
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len = cmd->response_size;
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} else {
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len = cmd->buffer_size;
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rc = VMCP_ERR_TOOSMALL;
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}
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/* Exits on failure */
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cmd->response = (char *)util_zalloc(len + 1);
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if (read_buffer(fd, cmd->response, len) == -1) {
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rc = VMCP_ERR_READ;
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free(cmd->response);
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cmd->response = NULL;
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}
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fail:
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close(fd);
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free(cpcmd);
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return rc;
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}
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