KR20070056862A - Memory Structure and Memory Corruption Detection Method for Dynamic Memory Allocation of System Programs - Google Patents

Abstract

The present invention relates to a memory structure for dynamic memory allocation of a system program and a memory corruption detection method, comprising: a header field unit including at least one specific value for detecting memory corruption according to a memory allocation request of a program, and actual data; The present invention relates to a memory structure and a memory corruption detection method for dynamic memory allocation of a system program for dynamically allocating a memory block divided into a real data field unit for storing a data field and a trailer field including a program corruption information corrupting a corresponding memory. .

Description

MEMORY STRUCTURE AND MEMORY CORRUPTION FINDING METHOD FOR DYNAMIC MEMORY ALLOCATION OF SYSTEM PROGRAM}

1 illustrates a memory structure for dynamic memory allocation of a system program of the present invention.

2 illustrates a c style data structure of a memory header and a trailer according to the present invention.

3 is a diagram illustrating a dynamic memory allocation process of a system program according to the present invention.

4 is a diagram illustrating a dynamic memory writing process of a system program according to the present invention.

5 is a diagram illustrating a dynamic memory releasing process of a system program according to the present invention.

Explanation of symbols on the main parts of the drawings

10: header field 11: field next

12: prev field 13: size field

14: cookie field 15: preguard [] field

20: real data field 30: trailer field

31: postguard [] field 32: filename field

33: linenum field 34: taskid field

The present invention relates to a memory structure and a memory corruption detection method for dynamic memory allocation of a system program.

In general, S / W applications that operate on system boards such as microcontroller units (MCUs) are loaded and executed in memory (RAM) to dynamically allocate and use the necessary memory during operation. It will repeat the operation returned to the system.

In the process of repeatedly allocating, using, and releasing memory, if a programmer's mistake uses a memory area that is not allocated to the memory, the memory is damaged, resulting in a system crash.

That is, conventionally, when a memory corruption occurs in an arbitrary task of a running program because there is no buffer for memory corruption, the system is down and does not operate normally. In this case, it was also difficult to find out which task corrupted the memory.

Here, a task refers to a processor module that performs different functions among programs operated on a real time operating system (RTOS) of a system board. As described above, a task refers to a memory boundary allocated by the task. In addition, when memory corruption occurs using memory, the system does not operate normally, and when a memory corruption occurs, it is difficult to find out which task and which portion of the memory corruption have occurred.

Accordingly, an object of the present invention is to solve the above problems, and to prevent the memory corruption that causes the system to crash or operate abnormally to the maximum, and when such memory corruption occurs, in which part of the task the memory corruption occurs. The present invention provides a memory structure and a memory corruption detection method for dynamic memory allocation of a system program.

According to an aspect of the dynamic memory allocation system according to the present invention for achieving the above object, a header field portion including at least one specific value for detecting memory corruption in response to a memory allocation request of a program, and actual data And a memory allocation module for dynamically allocating a memory block divided into a real data field unit for storing and a trailer field including program damage information corrupting the corresponding memory.

The header field unit may include: a prev field unit in which pointer information indicating a previous memory block of a currently used memory block is set; a next field unit in which pointer information indicating a next memory block of a currently used memory block is set; and the actual data A size field unit for setting maximum size information of data that can be written to the field unit, a cookie field unit for setting a cookie value for checking memory corruption and memory authentication of the allocated memory block, and a memory of the allocated memory block It consists of a preguard [] field where the preguard value for detecting corruption is set.

The cookie value set in the cookie field part has a fixed value.

The trailer field unit may include a postguard [] field unit in which a postguard value for detecting memory corruption of the allocated memory block is set, a filename field unit in which a file name of a corresponding program that causes the memory corruption is set; And a linenum field portion for setting a linenum of the corresponding program that caused the memory corruption, and a taskid field portion for setting a task ID of the corresponding program for causing the memory corruption.

The preguard value set in the preguard [] field portion and the postguard value set in the postguard [] field portion have the same value.

On the other hand, according to one aspect of the dynamic memory allocation method of the program according to the present invention for achieving the above object, setting the preguard value and cookie value of the allocated memory block header according to the memory allocation request of the program, and Setting the postguard value of the memory block trailer to the same value as the preguard value of the header, setting the file name, line number, and task id of the program requesting the memory allocation to the corresponding fields of the trailer, respectively; And returning the start address of the actual data field of the memory block.

Meanwhile, according to an aspect of a dynamic memory writing method of a program according to the present invention for achieving the above object, a step of checking whether a value set in a cookie field of a memory block header allocated according to a memory allocation request of a program is changed; Starting writing of the data by referring to the start address of the actual data field of the memory block when the value set in the cookie field is not changed; and according to the value set in the size field of the memory block header. Checking whether data written in an actual data field of the memory block has been written over an allocated area; and if data written in the actual data field has not been written over an allocated area, the value set to the same value; To check if the preguard and postguard values of the memory block trailer have changed And if the preguard value and the postguard value have not been changed, terminating the corresponding data writing of the actual data field normally.

If the value set in the cookie field is changed, the method further includes the step of returning filename, linenum, and taskid of the corresponding program to indicate a portion of memory corruption.

If the data written in the actual data field exceeds the allocated area, the method may further include notifying a part of the memory corruption by returning the filename, linenum, and taskid of the corresponding program.

When the preguard value and the postguard value are changed, the method may further include informing the part of the memory corruption by returning the filename, linenum, and taskid of the corresponding program.

On the other hand, according to an aspect of the dynamic memory release method of the program according to the present invention for achieving the above object, the step of checking whether the value set in the cookie field of the corresponding memory block header in response to the memory release request of the program, and If the value set in the cookie field has not changed, checking whether a preguard value of the memory block header has changed, and if the preguard value has not changed, checking whether a postguard value of the memory block trailer has changed; If the postguard value hasn't changed, then it frees the memory block.

If the value set in the cookie field is changed, the method further includes the step of returning filename, linenum, and taskid of the corresponding program to indicate a portion of memory corruption.

If the preguard value is changed, the method may further include informing a part of the memory corruption by returning a filename, linenum, and taskid of the corresponding program.

If the postguard value is changed, the method may further include informing a part of memory corruption by returning a filename, linenum, and taskid of the corresponding program.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, detailed descriptions of preferred embodiments of the present invention will be described with reference to the accompanying drawings. It should be noted that reference numerals and like elements among the drawings are denoted by the same reference numerals and symbols as much as possible even though they are shown in different drawings. In the following description of the present invention, if it is determined that a detailed description of a related known function or configuration may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted.

1 is a diagram illustrating a memory structure for dynamic memory allocation of a system program of the present invention, and FIG. 2 is a diagram illustrating a c style data structure of a memory header and a trailer according to the present invention.

As shown in FIG. 1, a memory block for dynamic memory allocation of a system program is divided into a header field 10, an actual data field 20, and a trailer field 30.

That is, a program running on the RTOS of the system board is allocated the memory of the structure as shown in FIG. 1, and the program requesting the memory allocation receives the start address of the actual data to be used and can use the memory.

Here, the header field 10 is divided into a next field 11, a prev field 12, a size field 13, a cookie field 14, and a preguard [] field 15.

The next field 11 stores a pointer to a next memory block based on a memory block currently being used among a plurality of memory blocks for memory allocation.

The prev field 12 stores a pointer indicating a previous memory block based on a memory block currently being used among a plurality of memory blocks for memory allocation.

The size field 13 stores maximum size information of real data that can be written to the real data field 20.

The cookie field 14 is used for checking memory corruption and memory authentication on the header side, and a fixed cookie value is set.

For example, the cookie field 14 is set to a fixed cookie value such as "OxAECB", and the fixed cookie is used in a process in which a system program dynamically allocates memory and then uses or releases the memory. Depending on whether the value is changed, it is possible to check whether the memory is corrupted.

That is, when the fixed cookie value of the cookie field 14 is changed, memory writing or cancellation cannot be performed, and the filename, linenum, and taskid of the program requesting the memory allocation are returned.

The preguard [] field 15 sets a specific preguard value when allocating memory according to a memory allocation request of a specific program operating on a system board. For example, it is set to a specific value such as "OxCAFE", and the memory is damaged depending on whether the specific value is changed in the process of using the memory after the system program is dynamically allocated the memory or using the memory. Can be checked.

That is, when a specific value set in the preguard [] field 15 is changed, memory writing or writing cannot be performed, and the filename, linenum, and taskid of the program requesting the memory allocation are returned.

The trailer field 30 is divided into a postguard [] field 31, a filename field 32, a linenum field 33, and a taskid field 34.

The postguard [] field 31 sets a specific value when allocating memory according to a memory allocation request of a specific program operating on a system board. Here, the specific value is set to the same value as the specific value set in the preguard [] field 15 of the header field 10.

For example, it is set to a specific value such as "OxCAFE", and the memory is damaged depending on whether the specific value is changed in the process of using the memory after the system program is dynamically allocated the memory or using the memory. Can be checked.

In other words, when a specific value set in the postguard [] field 31 is changed, memory writing or writing cannot be performed, and filename, linenum, and taskid of the corresponding program requesting memory allocation are returned.

In the filename field 32, the linenum field 33, and the taskid field 34, the file name, line number, and task id of the program that has currently requested memory allocation are set in each field.

In particular, the filename field 32, the linenum field 33, and the taskid field 34 of the trailer field 30 are damaged in some parts when a memory corruption occurs. It will be used to find out if it is.

The c style data structure of the memory header and the trailer described above has the structure shown in FIG. 2.

3 is a diagram illustrating a dynamic memory allocation process of a system program according to the present invention.

As shown in FIG. 3, a memory block divided into a header, actual data, and a trailer field is allocated according to a memory allocation request of a program running on an RTOS of a system board.

That is, when allocating memory, first, the preguard value of the header is set to a specific value (S10). For example, it is set to a specific value such as "OxCAFE".

Next, the cookie value of the header is set to a specific value (S20). For example, it is set to a specific value such as "OxAECB" and the specific value set at this time has a fixed value.

Subsequently, the postguard value of the trailer is set to the same value as the preguard value of the header (S30). For example, it is set to a specific value such as "OxCAFE".

Subsequently, the file name, line number, and task id of the program that has currently requested memory allocation are set in the filename field, the linenum field, and the taskid field of the trailer (S40), respectively.

Subsequently, the program requesting the memory allocation is returned (S50) with the start address of the actual data field actually used to use the memory.

4 is a diagram illustrating a dynamic memory writing process of a system program according to the present invention.

As shown in FIG. 4, when a program requesting a memory allocation receives a start address of an actual data field to be actually used to use a corresponding memory, first, it is checked whether a fixed value set in a cookie field of a header is changed. (S10).

As a result of the check, if the fixed value set in the cookie field is not changed, data is written to the real memory by referring to the start address of the actual data field indicated by the pointer (W 20).

Subsequently, it is checked whether data written in the actual data area is written beyond the boundary of the memory area based on the maximum value information of the actual data set in the size field of the header (S30).

As a result of the check, if the data written in the actual data area is not written beyond the boundary of the memory area, it is checked whether the preguard value or the postguard value set to the same value is changed (S40).

As a result of the check, if the preguard value or the postguard value set to the same value is not changed, the corresponding data is normally written to the allocated real memory area (S50).

However, if the fixed cookie value is changed in step S10 or if the data written in the actual data area is written beyond the boundary of the corresponding memory area in step S30, or is set to the same value in step S40 If the value or postguard value is changed by the user option, the memory is corrupted and the program cannot write the data to the allocated memory.

Accordingly, by returning the filename, linenum, and taskid of the corresponding program requesting the memory allocation (S60), the memory corruption may be reported, thereby facilitating debugging related to memory corruption.

5 is a diagram illustrating a dynamic memory releasing process of a system program according to the present invention.

As shown in FIG. 5, after the program uses the allocated memory, it is first checked whether the fixed cookie value of the header is changed in order to release the memory (S10).

As a result of the check, if the fixed value set in the cookie field is not changed, it is checked whether the header preguard value has changed (S20).

As a result of the check, if the preguard value of the header has not been changed, it is successively checked whether the postguard value of the trailer has changed (S30).

Subsequently, when the postguard value of the trailer is not changed, the corresponding memory is released and moved to a free block among the allocated memory blocks (S40).

However, if the fixed cookie value is changed in step S10, the preguard value of the header is changed in step S20, or the postguard value of the trailer is changed in step S30, the memory is corrupted. In this case, the memory used by the program cannot be released.

Accordingly, by returning the filename, linenum, and taskid of the corresponding program (S50) to inform the part where the memory corruption has occurred, debugging of the memory corruption can be facilitated.

In the above, specific preferred embodiments of the present invention have been illustrated and described. However, the present invention is not limited to the above-described embodiment, and various modifications can be made by any person having ordinary skill in the art without departing from the gist of the present invention attached to the claims. will be.

According to the present invention, by examining the memory corruption of the program running on the RTOS of the system board in advance, and ignoring the memory corruption that does not affect the system according to the degree of memory corruption, the stability of the system is improved, and the memory In the event of corruption, the memory corruption can be easily found, which shortens the development time for developing a program for each board.

In addition, when a memory corruption problem occurs in a running system, memory corruption related debugging is facilitated, thereby reducing the maintenance cost of the system.

Claims (14)

According to a memory allocation request of a program, a header field unit including at least one specific value for detecting memory corruption, an actual data field unit for storing actual data, and a trailer field including program corruption information corrupting the memory A dynamic memory allocation system comprising a memory allocation module for dynamically allocating memory blocks divided by. The method of claim 1, The header field unit, A prev field unit in which pointer information indicating a previous memory block of a memory block currently being used is set; A next field unit in which pointer information indicating a next memory block of a memory block currently being used is set; A size field unit for setting data maximum size information that can be written to the actual data field unit; A cookie field unit configured to set a cookie value for checking memory corruption and memory authentication of the allocated memory block; And And a preguard [] field part in which a preguard value for detecting memory corruption of the allocated memory block is set. The method of claim 2, And a cookie value set in the cookie field unit has a fixed value. The method of claim 2, The trailer field unit, A postguard [] field unit configured to set a postguard value for detecting memory corruption of the allocated memory block; A filename field part for setting a file name of the program that caused the memory corruption; A linenum field unit configured to set a linenum of a corresponding program that causes the memory corruption; And A dynamic memory allocation system comprising a taskid field portion in which a task ID of a corresponding program that causes memory corruption is set. The method of claim 4, wherein And a preguard value set in the preguard [] field portion and a postguard value set in the postguard [] field portion have the same value. Setting a preguard value and a cookie value of an allocated memory block header according to a memory allocation request of a program; Setting a postguard value of the memory block trailer to a value equal to the preguard value of the header; Setting a file name, a line number, and a task id of the program requesting the memory allocation in corresponding fields of the trailer; And And returning a start address of an actual data field of the allocated memory block. Checking whether a value set in a cookie field of an allocated memory block header is changed according to a memory allocation request of a program; Starting writing of a corresponding data by referring to a start address of an actual data field of the memory block when a value set in the cookie field is not changed; Checking whether data written in an actual data field of the memory block exceeds an allocated area according to a value set in a size field of the memory block header; Checking whether the preguard value and the postguard value of the memory block trailer set to the same value have been changed when data written in the actual data field has not been written beyond the allocated area; And And when the preguard value and the postguard value have not changed, terminating the data writing of the actual data field normally. The method of claim 7, wherein And returning filename, linenum, and taskid of the corresponding program when the value set in the cookie field is changed, to indicate a portion where a memory corruption has occurred. The method of claim 7, wherein If the data written in the actual data field exceeds the allocated area, returning filename, linenum, and taskid of the corresponding program to indicate a portion where memory corruption has occurred; . The method of claim 7, wherein If the preguard value and postguard value is changed, returning the filename, linenum, and taskid of the program to notify the portion of the memory corruption occurs. Checking whether a value set in a cookie field of a corresponding memory block header is changed according to a memory release request of a program; Checking whether a preguard value of the memory block header has been changed if the value set in the cookie field has not been changed; If the preguard value has not changed, checking whether the postguard value of the memory block trailer has changed; And If the postguard value has not changed, releasing the memory block. The method of claim 11, If the value set in the cookie field is changed, returning filename, linenum, and taskid of the corresponding program to notify a portion where memory corruption occurs. The method of claim 11, If the preguard value is changed, returning filename, linenum, and taskid of the corresponding program to indicate a portion where memory corruption has occurred. The method of claim 11, If the postguard value is changed, returning the filename, linenum, taskid of the program to inform the portion of the memory corruption occurs.

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