JP2011221785A - Information processor, memory management method and program - Google Patents

Abstract

An information processing apparatus in which an application performs a predetermined function using a reserved memory area and can easily provide an environment in which a buffer overrun is unlikely to occur.
An information processing apparatus in which an application performs data processing using a reserved memory area stores information that includes information on occurrence of buffer overrun and identification information of the application that has caused the buffer overrun. And when acquisition of the memory area is requested by the means and the application, the identification information of the application is acquired, the generation information stored in the storage means is acquired using the identification information, and based on the acquired generation information A memory management unit that determines the capacity of the memory area to be secured, secures the memory area, and stores the generated information in the storage unit when a buffer overrun occurs.
[Selection] Figure 2

Description

  The present invention relates to an information processing apparatus or the like in which an application executes a predetermined function using a reserved memory area, and in particular, an environment where it is difficult to generate a buffer overrun that accesses the memory beyond the memory area. The present invention relates to an information processing apparatus and the like that can be provided.

  In general-purpose computers and dedicated computers that cooperate with other devices, various applications using programs are used to realize predetermined functions. Such an application is normally executed by the operation of a CPU in accordance with an instruction of a program, and in that case, data is written in a memory included in the computer and processing is executed.

  The memory area to be used is secured when an application requests the OS (operating system) of the computer. After that, the application executes a predetermined process using the memory area allocated by the OS, but exceptionally, the application accesses the memory beyond the boundary of the allocated memory area (here, Called buffer overrun). When such a situation occurs, there is a possibility that the program may run away, and usually, countermeasures such as stopping application processing are taken.

  For example, in the controller unit of the printer, various processes based on a program (application) are performed, but this buffer overrun may occur when image data to be handled becomes an unexpected amount of data. In particular, there is a risk of this occurring in processing that handles data of variable length.

  Further, Patent Document 1 below discloses management of memory usage in a garbage collection-compatible environment as a related technique.

JP 2007-157131 A

  When the above-described buffer overrun has occurred, conventionally, it has been generally considered that the program of the application is defective and the program is corrected. In general, such a program cannot be corrected by the user, and the analysis of identifying the environment and conditions in which such a situation has occurred is also a difficult task for the program provider. It was difficult to solve the problem immediately. Therefore, it is inconvenient for a user who uses the application.

  Therefore, an object of the present invention is an information processing apparatus in which an application executes a predetermined function using a reserved memory area, and an environment in which a buffer overrun that accesses the memory beyond the memory area is difficult to occur. It is to provide an information processing apparatus and the like that can easily provide the information.

  In order to achieve the above object, according to one aspect of the present invention, there is provided an information processing apparatus that realizes a predetermined function by performing data processing by an application using a reserved memory area, wherein the application stores the memory area. A buffer overrun occurrence information for accessing the memory beyond the storage area, and storing means for storing information including identification information of the application that has caused the buffer overrun, and requesting to secure the memory area from the application The identification information of the application is acquired, the generation information of the buffer overrun generated by the application stored in the storage unit is acquired using the identification information, and the acquired generation information is included in the acquired generation information. And determining the capacity of the memory area to be secured based on the memory area Secured, when the application generates the buffer overrun, and stores the generated information in the storage means comprises a memory management unit, and it is.

  In the above invention, a preferable aspect is that, when the acquired generation information indicates that the buffer overrun has occurred in the past, the memory management unit uses a capacity indicated by the application in the request. A larger capacity is determined as the capacity of the memory area to be secured.

  Furthermore, in the above invention, a preferred aspect is characterized in that the memory management means increases the determined capacity in accordance with the number of buffer overruns generated in the past.

  In order to achieve the above object, according to another aspect of the present invention, there is provided a memory management method in an information processing apparatus that realizes a predetermined function by an application performing data processing using a reserved memory area. In the processing device, the control means and information on occurrence of buffer overrun for accessing the memory beyond the memory area by the application and information including identification information of the application causing the buffer overrun are stored. Storage means, and when the control means is requested by the application to secure the memory area, the control means obtains identification information of the application and stores the identification information using the identification information. Acquires the occurrence information of the buffer overrun generated by the application. Determining the capacity of the memory area to be secured based on the acquired occurrence information and securing the memory area; and the control means, when the application causes the buffer overrun, the storage Storing the generated information in a means.

  In order to achieve the above object, according to yet another aspect of the present invention, a memory management process is performed on an information processing apparatus that realizes a predetermined function by performing data processing by an application using a reserved memory area. In the memory management program to be executed, the information processing apparatus includes information on occurrence of a buffer overrun in which the application accesses the memory beyond the memory area, and identification information on the application that has caused the buffer overrun When the information is stored and the memory area is requested by the application, the identification information of the application is obtained, and the buffer generated by the application is stored in the storage unit using the identification information. Acquires the occurrence information of overrun, and the acquired occurrence Determining a capacity of the memory area to be secured based on the information and securing the memory area; and storing the generated information in the storage means when the application generates the buffer overrun And causing the information processing apparatus to execute.

  Further objects and features of the present invention will become apparent from the embodiments of the invention described below.

1 is a configuration diagram according to an embodiment of a printer including an information processing apparatus to which the present invention is applied. 4 is a configuration diagram for explaining an operation of an application in a controller unit 3. FIG. It is the flowchart which illustrated the procedure of the process by the memory management module MM.

  Embodiments of the present invention will be described below with reference to the drawings. However, such an embodiment does not limit the technical scope of the present invention. In the drawings, the same or similar elements are denoted by the same reference numerals or reference symbols.

  FIG. 1 is a configuration diagram according to an embodiment of a printer including an information processing apparatus to which the present invention is applied. The controller unit 3 shown in FIG. 1 is an information processing apparatus to which the present invention is applied. When an overrun occurs in an application process performed by the apparatus, it is recorded and a memory reservation request from the application is recorded. At times, based on the recording, a capacity increased from the requested capacity is secured to provide an environment in which buffer overrun is unlikely to occur.

  As shown in FIG. 1, the printer 2 is a general printer that executes printing according to a print request from the host computer 1, and the controller unit 3 is an example of an information processing apparatus to which the present invention is applied.

  The host computer 1 is a host device of the printer 2 that instructs the printer 2 to print, and is configured by a personal computer or the like. Although not shown, the host computer 1 has the same hardware configuration as a general computer, and includes a CPU, a RAM, a ROM, a hard disk, a display device, an input device, and the like.

  The host computer 1 is provided with a driver responsible for the print instruction function. When a print request is received from the user, print job data including various printing conditions is generated and transmitted to the printer 2. The driver includes a program that instructs processing, a control device (such as the CPU) that executes processing according to the program, and the like.

  The printer 2 includes a controller unit 3 and a print execution unit 4. When the controller unit 3 receives the print job data, the controller unit 3 executes various processes on the image data included in the data and generates data to be transferred to the print execution unit 4. The controller unit 3 controls each unit of the printer 2 such as a user interface (not shown).

  As shown in FIG. 1, the controller unit 3 includes an I / F 11, a CPU 12, a ROM 13, a RAM 14, a NVRAM 15, an engine I / F 16, and the like. The I / F 11 is a part that manages communication with the host computer 1. The CPU 12 executes various processes performed by the controller unit 3 in accordance with a program stored in the ROM 13 or the like. The RAM 14 is a memory that temporarily stores data of an image to be printed. The NVRAM 15 is a non-volatile memory, and stores information that should be stored even when the printer 2 is turned off. In this area, buffer overrun history information (occurrence information) described later is stored. The engine I / F 16 is a part that arranges data to be finally transferred to the print execution unit 4 and transmits the data.

Each function executed by the CPU 12 according to the program is a function of each application in the controller unit 3. In other words, each function executed by the program is executed by each application provided in the controller unit 3. The application is constituted by a corresponding program stored in the CPU 12 and the ROM 13 or the like. Each application uses the allocated area of the RAM 14 when executing the process.

  The print execution unit 4 is a part that executes printing on a print medium based on the transferred data.

  FIG. 2 is a configuration diagram for explaining the operation of the application in the controller unit 3. FIG. 2 shows the functional configuration of portions related to memory access by the application.

  The operating system OS is a general OS in a computer, and mainly manages I / O management, memory management, and the like. The operating system OS is composed of programs stored in the CPU 12 and the ROM 13.

  The memory management module MM is a characteristic part of the controller unit 3 and has a function of mediating memory access from each application AP. Specific processing contents will be described later, but when the application AP has caused a buffer overrun, it is recorded in the NVRAM 15, and when a request for securing the memory is received from the application AP, the past is based on the record. The memory securing amount is determined from the history of the buffer overrun and the operating system OS is requested to secure the memory. Note that the memory management module MM includes a program stored in the CPU 12 and the ROM 13.

  The application AP is an application of the controller unit 3 described above, and executes each function using the memory ME. For example, it performs functions such as a development process for converting a print target image into image data in pixel units.

  The memory ME is the RAM 14 here, and when the application AP executes a process, the operating system OS allocates an area for this purpose, and data is written in the area.

  As described above, the printer 2 having the configuration as described above has a feature in securing the memory in the controller unit 3, and the specific contents thereof will be described below. FIG. 3 is a flowchart illustrating an example of a processing procedure performed by the memory management module MM. Here, a series of processing contents when a memory securing request is received from the application AP will be described.

  When the application AP executes the process, it is necessary to secure a predetermined capacity area for use in the memory ME, and a request to that effect is sent to the memory management module MM. The request is made to the OS in the conventional apparatus, but here, it is determined by the program of the application AP to be made to the memory management module MM that mediates memory reservation. Further, the required secured amount is also determined by the program of the application AP.

When the request is issued, the memory management module MM receives the request (step S1 in FIG. 3). At this time, the memory management module MM acquires the requested memory allocation amount information from the received information and also acquires the identification information (application ID) of the requesting application AP. The application ID is another application AP
And the application AP may be included in the request, and if the address on the memory ME loaded with the application AP program is fixed, the address is acquired as an application ID. Also good.

  Next, the memory management module MM refers to the buffer overrun history information (occurrence information) stored in the NVRAM 15 (step S2). The buffer overrun history information is recorded each time a buffer overrun occurs by the processing of the memory management module MM described later, and includes at least the application ID of the application AP that has caused the buffer overrun. , Recorded in time series. Therefore, by referring to the history information, it is possible to know the number of buffer overruns that have occurred in the past by the application AP that has requested memory allocation this time. The history information may include information on the date and time when the buffer overrun occurred.

  The memory management module MM extracts (acquires) the history information of the application AP from the acquired application ID of the requesting application AP by referring to the history information, and the past buffer overrun caused by the application AP. Get the number of times.

  Next, the memory management module MM determines a memory reservation amount requested from the operating system OS based on the acquired number of times (step S3). The determination of the memory allocation amount is larger than the above-described allocation amount requested by the application AP when a buffer overrun has occurred in the past, that is, when the number of times of acquisition is 1 or more. Do as follows. Specifically, it can be performed by several methods, but as an example, the larger the number of past buffer overruns, the larger the required memory allocation. In this case, for example, if the number of times is 0, the secured amount as requested from the application AP is determined, and if the number of times is 1, it is determined to be 1.5 times the secured amount requested from the application AP. If the number of times is 2, it is further determined to be 1.5 times, and thereafter, similarly, every time the number of times increases, it is determined to increase at the same magnification. Alternatively, each time the number of times increases, the predetermined amount (for example, 50%) of the secured amount requested from the application AP is determined to increase.

  As another method, if the number of times acquired is 0, the secured amount is determined as requested by the application AP. If the number of times is 1 or more, the application AP is used in any case. The secured amount requested from is determined to be an amount increased by a predetermined rate. In this case, as the history information, the application ID of the application AP that has caused a buffer overrun in the past may be recorded once.

  In addition, information that is more than a predetermined period in the history information may not be included in the number of times described above. That is, it is possible not to consider the recording of old buffer overruns that occurred before a certain period. This is because the program of the application AP has been corrected, and such old information may not indicate the state of the program at that time.

  Thereafter, the memory management module MM secures the determined memory amount for the operating system OS (step S4). In response to the request, the operating system OS executes a process of allocating the requested amount of area to the memory ME, and notifies the memory management module MM of the fact when the area is secured.

The memory management module MM that has received the notification notifies the requesting application AP of the memory allocation result (step S5). At this time, since the address of the reserved area is notified from the operating system OS, the address is notified to the application AP.

  Note that if the operating system OS cannot allocate the requested amount of memory, it is processed as an error, and a series of processing for the memory securing request ends.

  After the notification, since the memory of the requesting application AP has been secured, the requesting application AP starts actual processing and performs memory access to use the secured memory area. Since this memory access is also performed in the controller unit 3 via the memory management module MM, it is programmed to make a request to the memory management module MM.

  When the memory management module MM receives the memory access request (Yes in step S6), the memory management module MM acquires the application ID of the requesting application AP in the same manner as described above, and then performs the requested memory access. (Step S7). That is, data is written in the allocated area of the memory ME.

  Here, the memory management module MM waits for occurrence of a buffer overrun due to the memory access (step S8), a memory release instruction (step S9), or a next memory access request (step S6).

  If a buffer overrun has occurred due to the memory access (Yes in step S8), this is detected by the operating system OS, and the memory management module MM adds to the history information the buffer overrun that has occurred. Record (step S11). Specifically, the NVRAM 15 is accessed and the acquired application ID of the request source is recorded together with predetermined information. Note that, when the buffer overrun is detected by the operating system OS, it is set in advance so that the process shifts to the memory management module MM as an interrupt process. Specifically, the address of the program of the memory management module MM is set in the corresponding part of the interrupt vector table.

  In this case, thereafter, the processing by the application AP is stopped, and the series of processing for securing the memory by the memory management module MM is completed.

  If the next memory access request is received without occurrence of buffer overrun (No in step S8, No in S9, Yes in S6), the process is executed from the above-described process in step S7.

  If a memory release request is received from the application AP that has made the access request (Yes in step S9), the memory management module MM releases the allocated area of the memory ME. The release request is also programmed in the application AP so as to be made to the memory management module MM. When such release processing is performed, a series of processing for securing the memory by the memory management module MM ends.

  As described above, the memory securing process by the memory management module MM is executed every time a request is made from the application AP.

As described above, in the controller unit 3 according to the present embodiment, when a memory allocation request is made from an application AP, the memory management module MM has received a buffer overrun in the past by the application AP. In this case, a memory area having a capacity larger than the requested capacity is secured, and if a buffer overrun occurs in order to secure such a memory, the record is left. Therefore, when an application AP is used, in the case of an application AP that has caused buffer overrun in the past, the memory capacity automatically secured by the memory management module MM is adjusted so as to increase, and buffer overrun may occur. Low. Therefore, the number of times the application is stopped is reduced, and user convenience is improved. Further, it is possible to cope with a buffer overrun without immediately modifying the program of the application AP. Further, by sequentially increasing the memory capacity to be secured according to the number of past buffer overruns, the possibility of causing a buffer overrun is further reduced.

  In the above embodiment, the memory management module MM is realized by software. However, a function similar to the module or a part of the function may be realized by hardware such as an MMU.

  In the above embodiment, the information processing apparatus to which the present invention is applied is the controller unit in the printer, but the present invention can be applied to other information processing apparatuses such as a general-purpose computer. When applied to a general purpose environment such as a personal computer, when the same module as the memory management module MM is activated, the process is transferred to the module as an interrupt process when a buffer overrun occurs. As described above, when the module rewrites the setting, the same processing as that in the above embodiment can be executed. On the application side, programs that use the module are programmed to issue a memory allocation request and memory access request to the module, and applications that do not use the module use the memory for the OS as before. Make a secure request.

  The protection scope of the present invention is not limited to the above-described embodiment, but covers the invention described in the claims and equivalents thereof.

  DESCRIPTION OF SYMBOLS 1 Host computer, 2 Printer, 3 Controller part, 4 Print execution part, 11 I / F, 12 CPU (control means), 13 ROM, 14 RAM, 15 NVRAM (storage means), 16 Engine I / F, OS operating system MM memory management module (memory management means) AP application ME memory

Claims (5)

An information processing apparatus that realizes a predetermined function by an application performing data processing using a reserved memory area,
Storage means for storing information including occurrence information of a buffer overrun in which the application accesses the memory beyond the memory area and including identification information of the application that has caused the buffer overrun;
When the application requests to secure the memory area, the buffer overrun occurrence information generated by the application that acquires the identification information of the application and is stored in the storage unit using the identification information And determining the capacity of the memory area to be secured based on the obtained occurrence information to secure the memory area,
An image processing apparatus comprising: memory management means for storing the generated information in the storage means when the application generates the buffer overrun. In claim 1,
The memory management means, when the obtained occurrence information indicates that the buffer overrun has occurred in the past, the capacity of the memory area to secure the capacity larger than the capacity indicated by the application in the request An image processing apparatus characterized by determining as follows. In claim 2,
The memory processing unit increases the capacity to be determined according to the number of buffer overruns generated in the past. A memory management method in an information processing apparatus for realizing a predetermined function by an application performing data processing using a reserved memory area,
In the information processing apparatus, control means and information on occurrence of buffer overrun in which the application accesses the memory beyond the memory area, the information including identification information of the application that has caused the buffer overrun. Storage means for storing, and
The buffer generated by the application that acquires the identification information of the application when the control unit is requested by the application to secure the memory area and that is stored in the storage unit using the identification information Obtaining overrun occurrence information, determining the capacity of the memory area to be secured based on the obtained occurrence information, and securing the memory area;
The control means includes a step of storing the generation information in the storage means when the application causes the buffer overrun. The memory management method, comprising: A memory management program for causing an information processing apparatus that implements a predetermined function by performing data processing using an allocated memory area to execute a memory management process,
In the information processing apparatus, information on occurrence of a buffer overrun in which the application accesses the memory beyond the memory area, and information including identification information of the application that has caused the buffer overrun is stored.
When the application requests to secure the memory area, the buffer overrun occurrence information generated by the application that acquires the identification information of the application and is stored in the storage unit using the identification information And determining the capacity of the memory area to be secured based on the obtained occurrence information and securing the memory area;
A memory management program that causes the information processing apparatus to execute a step of storing the generated information in the storage means when the application generates the buffer overrun.

Images