JP3607658B2 - Portable electronic device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention is referred to as a so-called IC card having a control element such as a non-volatile memory that can be written and rewritten and a CPU and a means for inputting / outputting data from the outside. The present invention relates to a portable electronic device.
[0002]
[Prior art]
In this type of IC card, when data is rewritten to the non-volatile memory, an unexpected accident occurs during data rewriting (such as a power failure or removal of the IC card, which is referred to as tearing in the present invention). ) Occurs, there is a system in which the content of the writing location guarantees the state before or after writing (in the present invention, this guarantee is called transaction atomicity).
[0003]
Data rewriting is performed once on a specific area in the nonvolatile memory called a commit buffer, and then on the actual writing area of the nonvolatile memory. As a result, if tearing occurs before all the write data is written in the commit buffer area, the data before the rewrite remains in the actual write area, and after all the write data is written in the commit buffer area. When tearing occurs, the rewritten data remains in the commit buffer area.
[0004]
In the former case, when the IC card is restarted after the occurrence of tearing, it can be assured that the data at the writing location is before rewriting. In the latter case, after restarting the IC card after occurrence of tearing, the contents of the commit buffer area are reflected in the writing location (in the present invention, this processing is called roll forward), so that the data at the writing location is rewritten. Can be guaranteed. The above is the implementation of transaction atomicity.
[0005]
[Problems to be solved by the invention]
However, the above-described transaction atomicity technique is problematic because the means for notifying the roll-forward timing and the occurrence of tearing are not clarified.
[0006]
For example, in a multi-application card having a plurality of application programs, the application program that was operating when tearing occurred and the application program that is operated after restarting the IC card after tearing are sufficiently different. Even if the occurrence of tearing is notified while another application program is running after the IC card is restarted, this application program cannot determine the treatment. Also, if the transaction atomicity function is used while this application program is operating, the contents of the commit buffer area at the time of tearing will be destroyed and roll forward will not be possible.
[0007]
Therefore, the present invention automatically performs roll forward after restarting after occurrence of tearing, and the application program that was operating at the time of occurrence of tearing is the fact that tearing occurs after the application program is selected after restarting. It is an object of the present invention to provide a portable electronic device that can effectively construct a countermeasure against tearing including an external system by having means for knowing the contents of the commit buffer area at that time.
[0008]
[Means for Solving the Problems]
Portable electronic device of the present invention, when a command is inputted from the outside, by performing a predetermined process corresponding to the command in the portable electronic apparatus having a function of outputting the processing result to the external, selectively A plurality of application programs to be executed and storage means in which the storage contents can be rewritten , and the storage provided in the storage means for writing the write data and the write data to guarantee transaction atomicity When performing a write that guarantees transaction atomicity and a commit buffer area that temporarily holds a write destination address of the means, a write data is first written to the commit buffer area, and then the storage means A first means for writing the write data to the actual write area of The second means that can determine the start of writing to the memory buffer area, the start and end of writing to the actual writing area of the storage means, and when the first command from the outside is input when the portable electronic device is activated, If the second means remains in the state of starting writing to the actual write area, the third means for executing processing for reflecting the contents of the commit buffer area in the actual write area of the storage means, and the storage And a fourth means capable of judging the start of writing to the commit buffer area and the start and end of writing to the actual write area of the storage means corresponding to each of a plurality of application programs in the means, When a program is selected, the application program is selected at the time of the previous activation by the fourth means. , Where the committed writes writing to the buffer area has been started but the actual to the write area is characterized in that it can be determined that the application program that has not been finished.
[0010]
In the portable electronic device of the present invention, the selected application program is selected by the fourth means at the time of previous activation, and writing to the commit buffer area is started at that time. When it is determined that writing to the write area has not been completed, it is possible to determine how far the processing has progressed at the previous activation by referring to the commit buffer area.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0013]
FIG. 1 shows a configuration example of an IC card system that handles an IC card as a portable electronic device according to the present embodiment. In this IC card system, the IC card 101 is connected to a terminal device 103 such as a personal computer via a card reader / writer 102, and further configured to be able to communicate with a host computer 104 connected to the terminal device 103.
[0014]
FIG. 2 shows a configuration example of the IC card 101. A control element 201 such as a CPU as a control means, a nonvolatile data memory 202 as a storage means capable of rewriting stored contents, a working memory 203, and a program memory 204. , And a communication unit 205 for performing communication with the card reader / writer 102, which are constituted by one IC chip (or a plurality of IC chips). This IC chip is embedded in the IC card, and in the case of a contact type, it is electrically connected to the card reader / writer 102 via a contact portion on the surface of the IC card.
[0015]
The data memory 202 is used for storing various types of data, and is composed of, for example, a nonvolatile memory such as an EEPROM that can rewrite stored contents.
[0016]
The working memory 203 is a working memory for temporarily storing processing data when the control element 201 performs processing, and is configured by, for example, a RAM.
[0017]
The program memory 204 is composed of, for example, a mask ROM, and stores a control program for the control element 201 and the like.
[0018]
The communication unit 205 is for communicating with the card reader / writer 102 which is an external device.
[0019]
FIG. 3 shows the format of the data memory 202, which is divided into a system area E1 including an application management table area E11 and a commit buffer area E12, and an application area E2 in which a plurality of application programs are stored.
[0020]
FIG. 4 shows a format of the commit buffer area E12, which is divided into a commit buffer status flag part E13 represented by 1 byte and a commit buffer body part E14. The commit buffer status flag part E13 indicates the following status depending on its value.
[0021]
00: Commit buffer unused or end of writing to actual write area 01: Start of commit buffer processing 02 ... Start of writing to actual write area The commit buffer main body E14 writes the write data and the data memory 202 for writing the write data. A plurality of blocks composed of pairs with the write destination address data can be registered (stored).
[0022]
FIG. 5 shows an application management table area E11, in which data is registered as many as the number of application programs registered in the card. This data includes a commit state flag portion E15 represented by 1 byte.
[0023]
When the commit buffer state flag part E13 in FIG. 4 changes, the same value is held in the commit state flag part E15 of the corresponding application program. However, due to the roll forward process after the occurrence of tearing, the commit buffer state flag part E13 in FIG. 4 becomes “00”, but this is not reflected in the commit state flag part E15.
[0024]
Hereinafter, processing of the main part will be described.
[0025]
[Process when IC card starts]
When the IC card is activated and the first command (command input for the first time after activation) is received, or immediately before the use of the commit buffer area E12 is started, the value of the commit buffer status flag part E13 is viewed. If it is “02”, the data is reflected in the write destination address along the contents of the commit buffer main body E14, and the roll forward processing for setting the commit buffer status flag part E13 to “00” is performed.
[0026]
[Normal transaction atomicity processing]
When transaction atomicity processing is declared in the application program, the commit buffer state flag portion E13 is set to “01”, and subsequent writing processing is performed on the commit buffer area E12 until the end of transaction atomicity processing is declared. .
[0027]
When the transaction atomicity process end is declared, the above-described roll forward process is performed with the commit buffer status flag part E13 set to “02”. At the end of the process, the commit buffer status flag part E13 is returned to “00”, and the transaction atomicity process ends.
[0028]
[Tearing notification]
The application program can refer only to the contents of the corresponding application program from the application management table E11. Thereby, by referring to the commit state flag part E13, it can be determined whether tearing has occurred or not when it has been selected before. When the occurrence of tearing is confirmed, the application program cooperates with the outside to implement the response and clear (00) the commit state flag part E13.
[0029]
Next, the overall processing flow will be described with reference to the flowchart shown in FIG. When the IC card is activated, the control element 201 transmits initial response data called answer-to-reset (ATR) to the card reader / writer 102 (step S1), and enters a reception standby state. (Step S2).
[0030]
In this state, when the first command (first command after activation) is received from the card reader / writer 102 (step S3), the control element 201 refers to the value of the commit buffer status flag section E13 to thereby determine the commit buffer. It is checked whether or not there is unprocessed data in the area E12 (step S4). In this case, since there is no unprocessed data in the commit buffer area E12, processing for the received command is started (step S5).
[0031]
After the command processing is started, when the transaction atomicity processing start is declared in the application program (step S6), the control element 201 sets the commit buffer status flag section E13 to “01”, and all subsequent data write processing is performed as a transaction. The process is performed on the commit buffer area E12 until the end of the atomicity process is declared (step S7).
[0032]
Thereafter, when the transaction atomicity process end is declared in the application program (step S8), the control element 201 sets the commit buffer state flag part E13 to “02” and performs the roll forward process (step S9). At the end of the process, the commit buffer status flag part E13 is returned to “00”, and the transaction atomicity process ends.
[0033]
Next, when the command processing ends (step S10), the control element 201 transmits a response to the command processing to the card reader / writer 102 (step S11), and enters a reception standby state (step S12). When the second command (second command after activation) is received from the card reader / writer 102 (step S13), the control element 201 returns to step S5 and repeats the same processing as described above.
[0034]
By the way, for example, if tearing occurs during the roll forward process in step S9, that is, the process of reflecting the contents of the commit buffer area E12 to the area instructed to be written to the data memory 202, The IC card is restarted. When restarted, the control element 201 transmits initial response data called answer-to-reset (ATR) to the card reader / writer 102 (step S14), and enters a reception standby state (step S15). ).
[0035]
In this state, when the first command (first command after restart) is received from the card reader / writer 102 (step S16), the control element 201 refers to the value of the commit buffer status flag part E13 to commit the command. It is checked whether or not there is unprocessed data in the buffer area E12 (step S17). In this case, the commit buffer area E12 is “02”, that is, since there is unprocessed data in the commit buffer area E12, the area in which the unprocessed data in the commit buffer area E12 is instructed to be written to the data memory 202. And a roll-forward process for setting the commit buffer state flag part E13 to “00”.
[0036]
When the roll-forward process ends, the control element 201 starts a process for the received command (step S19).
[0037]
【The invention's effect】
As described above in detail, according to the present invention, after the occurrence of tearing, the roll forward is automatically performed after the restart, and the application program that was operating at the time of the occurrence of the tearing is selected after the restart. By having means for knowing the fact that post-tearing has occurred and the contents of the commit buffer area at that time, it is possible to provide a portable electronic device that can effectively construct a countermeasure against tearing including an external system.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a configuration example of an IC card system that handles an IC card according to an embodiment of the present invention.
FIG. 2 is a block diagram illustrating a configuration example of an IC card.
FIG. 3 is a diagram showing a format of a data memory.
FIG. 4 is a diagram showing a format of a commit buffer area.
FIG. 5 is a diagram showing a format of an application management table area.
FIG. 6 is a flowchart for explaining the overall processing flow;
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 101 ... IC card (portable electronic device), 102 ... Card reader / writer, 103 ... Terminal device, 104 ... Host computer, 201 ... Control element, 202 ... Data memory (storage means), 203 ... Working memory, 204 ... Program Memory, 205 ... communication unit, E1 ... system area, E2 ... application area, E11 ... application management table area, E12 ... commit buffer area, E13 ... commit buffer status flag part, E14 ... commit buffer main part.

Claims (2)

When a command is input from the outside, in the portable electronic device having a function of executing a predetermined process corresponding to the command and outputting the processing result to the outside,
A plurality of application programs to be selectively executed, and storage means capable of rewriting stored contents;
A commit buffer area that is provided in the storage means and temporarily holds write data and a write destination address of the storage means for writing the write data in order to guarantee transaction atomicity;
When performing writing that guarantees transaction atomicity, first write data is written to the commit buffer area, and then write data is written to the actual write area of the storage means. Means,
Second means capable of determining the start of writing to the commit buffer area, the start and end of writing to the actual write area of the storage means;
If the first command from the outside is input when the portable electronic device is activated, the storage means stores the contents of the commit buffer area if the second means remains in the write start state to the actual write area A third means for performing a process to be reflected in the actual writing area of
A fourth means capable of determining the start of writing to the commit buffer area and the start and end of writing to the actual write area of the storage means corresponding to each of a plurality of application programs in the storage means;
When the application program is selected, the application program is selected by the fourth means at the previous startup, and writing to the commit buffer area is started at that time, but writing to the actual writing area is completed. A portable electronic device characterized in that the application program can determine that it is not . The selected application program is selected by the fourth means at the time of previous activation, and writing to the commit buffer area is started at that time, but writing to the actual writing area is not completed. when it is determined that, portable electronic device according to claim 1, characterized in that it can be determined whether or not progressed far processing the last start time by referring to the commit buffer area.

Images