1tpm2_readclock(1)           General Commands Manual          tpm2_readclock(1)
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NAME

6       tpm2_readclock(1) - Retrieves the time information from the TPM.
7

SYNOPSIS

9       tpm2_readclock [OPTIONS]
10

DESCRIPTION

12       tpm2_readclock(1)  -Reads the current TPMS_TIME_INFO structure from the
13       TPM.  The structure contains the current setting of Time, Clock, reset‐
14       Count,  and  restartCount.   The structure is output as YAML to stdout.
15       The YAML output is defined as:
16
17              time: 13673142     # 64 bit value of time since last _TPM_Init or TPM2_Startup
18                                 # in ms.
19              clock_info:
20                clock: 13673142  # 64 bit value of time TPM has been powered on in ms.
21                reset_count: 0   # 32 bit value of the number of TPM Resets since the last
22                                 # TPM2_Clear.
23                restart_count: 0 # 32 bit value of the number of times that TPM2_Shutdown or
24                                 # _TPM_Hash_Start have occurred since the last TPM Reset or
25                                 # TPM2_Clear.
26                safe: yes        # boolean yes|no value that no value of Clock greater than
27                                 # the current value of Clock has been previously reported by
28                                 # the TPM.
29
30       This tool takes no arguments and no tool specific options.
31
32   References

COMMON OPTIONS

34       This collection of options are common to many programs and provide  in‐
35       formation that many users may expect.
36
37       · -h,  --help=[man|no-man]:  Display the tools manpage.  By default, it
38         attempts to invoke the manpager for the  tool,  however,  on  failure
39         will  output  a short tool summary.  This is the same behavior if the
40         "man" option argument is specified, however if explicit "man" is  re‐
41         quested,  the  tool  will  provide errors from man on stderr.  If the
42         "no-man" option if specified, or the manpager fails,  the  short  op‐
43         tions will be output to stdout.
44
45         To  successfully use the manpages feature requires the manpages to be
46         installed or on MANPATH, See man(1) for more details.
47
48       · -v, --version: Display version information for this  tool,  supported
49         tctis and exit.
50
51       · -V,  --verbose:  Increase the information that the tool prints to the
52         console during its execution.  When using this option  the  file  and
53         line number are printed.
54
55       · -Q, --quiet: Silence normal tool output to stdout.
56
57       · -Z, --enable-errata: Enable the application of errata fixups.  Useful
58         if an errata fixup needs to be applied to commands sent to  the  TPM.
59         Defining  the environment TPM2TOOLS_ENABLE_ERRATA is equivalent.  in‐
60         formation many users may expect.
61

TCTI Configuration

63       The TCTI or "Transmission Interface"  is  the  communication  mechanism
64       with  the TPM.  TCTIs can be changed for communication with TPMs across
65       different mediums.
66
67       To control the TCTI, the tools respect:
68
69       1. The command line option -T or --tcti
70
71       2. The environment variable: TPM2TOOLS_TCTI.
72
73       Note: The command line option always overrides  the  environment  vari‐
74       able.
75
76       The current known TCTIs are:
77
78       · tabrmd      -     The     resource     manager,     called     tabrmd
79         (https://github.com/tpm2-software/tpm2-abrmd).  Note that tabrmd  and
80         abrmd as a tcti name are synonymous.
81
82       · mssim  - Typically used for communicating to the TPM software simula‐
83         tor.
84
85       · device - Used when talking directly to a TPM device file.
86
87       · none - Do not initalize a connection with the TPM.  Some tools  allow
88         for off-tpm options and thus support not using a TCTI.  Tools that do
89         not support it will error when attempted to be used  without  a  TCTI
90         connection.   Does  not  support ANY options and MUST BE presented as
91         the exact text of "none".
92
93       The arguments to either the command  line  option  or  the  environment
94       variable are in the form:
95
96       <tcti-name>:<tcti-option-config>
97
98       Specifying  an  empty  string  for  either the <tcti-name> or <tcti-op‐
99       tion-config> results in the default being used for that portion respec‐
100       tively.
101
102   TCTI Defaults
103       When  a  TCTI  is not specified, the default TCTI is searched for using
104       dlopen(3) semantics.  The tools will  search  for  tabrmd,  device  and
105       mssim  TCTIs  IN THAT ORDER and USE THE FIRST ONE FOUND.  You can query
106       what TCTI will be chosen as the default by using the -v option to print
107       the  version information.  The "default-tcti" key-value pair will indi‐
108       cate which of the aforementioned TCTIs is the default.
109
110   Custom TCTIs
111       Any TCTI that implements the dynamic TCTI interface can be loaded.  The
112       tools internally use dlopen(3), and the raw tcti-name value is used for
113       the lookup.  Thus, this could be a path to the shared library, or a li‐
114       brary name as understood by dlopen(3) semantics.
115

TCTI OPTIONS

117       This collection of options are used to configure the various known TCTI
118       modules available:
119
120       · device: For the device TCTI, the TPM character device file for use by
121         the device TCTI can be specified.  The default is /dev/tpm0.
122
123         Example:    -T   device:/dev/tpm0   or   export   TPM2TOOLS_TCTI="de‐
124         vice:/dev/tpm0"
125
126       · mssim: For the mssim TCTI, the domain name or  IP  address  and  port
127         number  used  by  the  simulator  can  be specified.  The default are
128         127.0.0.1 and 2321.
129
130         Example: -T mssim:host=localhost,port=2321  or  export  TPM2TOOLS_TC‐
131         TI="mssim:host=localhost,port=2321"
132
133       · abrmd:  For  the abrmd TCTI, the configuration string format is a se‐
134         ries of simple key value pairs separated by a  ','  character.   Each
135         key and value string are separated by a '=' character.
136
137         · TCTI abrmd supports two keys:
138
139           1. 'bus_name'  :  The  name  of  the  tabrmd  service on the bus (a
140              string).
141
142           2. 'bus_type' : The type of the dbus instance (a string) limited to
143              'session' and 'system'.
144
145         Specify  the tabrmd tcti name and a config string of bus_name=com.ex‐
146         ample.FooBar:
147
148         \--tcti=tabrmd:bus_name=com.example.FooBar
149
150         Specify the default (abrmd) tcti and a config string of bus_type=ses‐
151         sion:
152
153         \--tcti:bus_type=session
154
155         NOTE:  abrmd  and tabrmd are synonymous.  the various known TCTI mod‐
156         ules.
157

EXAMPLES

159   Read the clock
160              tpm2_readclock
161              time: 13673142
162              clock_info:
163                clock: 13673142
164                reset_count: 0
165                restart_count: 0
166                safe: yes
167

Returns

169       Tools can return any of the following codes:
170
171       · 0 - Success.
172
173       · 1 - General non-specific error.
174
175       · 2 - Options handling error.
176
177       · 3 - Authentication error.
178
179       · 4 - TCTI related error.
180
181       · 5 - Non supported scheme.  Applicable to tpm2_testparams.
182

BUGS

184       Github Issues (https://github.com/tpm2-software/tpm2-tools/issues)
185

HELP

187       See the Mailing List (https://lists.01.org/mailman/listinfo/tpm2)
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191tpm2-tools                                                   tpm2_readclock(1)