proc_setattr Subroutine

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Purpose

Sets selected attributes of a process.

Library

Standard C library (libc.a)

Syntax

#include <sys/proc.h>
int proc_setattr (pid,attr,size)
pid_t pid;
procattr_t* attr;
size64_t size;

Description

The proc_setattr subroutines allows you to set selected attributes of a process. The list of selected attributes is defined in theprocattr_t structure defined in the <sys/proc.h> header file.

typedef struct { 
 	uchar core_naming; /* Unique core file names */
 	uchar core_mmap;   /* Dump nonanonymous mmap regions to core file */
 	uchar core_shm;    /* Dump shared memory to core file */
 	uchar aixthread_hrt; /* High resolution timer for thread */
   }procattr_t;

To set attributes for the calling process, a -1 can be passed as the first argument, pid.

Process A can set process attributes for Process B if one or more of the following items are true:

  • Process A and Process B have the same real or effective user ID.
  • Process A was executed by the root user.
  • Process A has PV_DAC_W privilege.

Parameters

Item Description
pid The identifier of the process whose information is to be retrieved.
attr A pointer to the user structure that will hold the information retrieved from the process kernel structure.
size The sizeof procattr_t structure is stored in the size parameter when calling API.

Return Values

Item Description
0 proc_setattr was successful.
-1 proc_setattr was unsuccessful. Global variable errno is set to indicate the error.

Error Codes

Item Description
EINVAL The size argument does not match the size of the procattr_t in the kernel.
EFAULT The attr value passed to the buffer is invalid.
ESRCH Could not locate the process identifier.
EPERM Insufficient privileges to read attributes from target the proc structure.

Example

setprocflags.c
#include <stdio.h> 
#include <sys/proc.h> 
#define P(_x_)  (((_x_) == PA_ENABLE) ? "ENABLE" : \ 
                ((_x_) == PA_DISABLE ? "DISABLE" : \ 
                (((_x_) == PA_IGNORE) ? "IGNORE" : "JUNK"))) 
int main(int argc, char *argv[]) 
{ 
        int rc; 
        procattr_t attr; 
        pid_t pid; 
        int naming,mmap,shm = 0; 
        if (argc &lt; ) { 
                printf("Syntax: %s <pid> <corenaming> <coremmap> <coreshm>\n", argv[0]); 
                exit(-1); 
        } 
        pid = atoi(argv[1]);
        bzero(&attr, sizeof(procattr_t));
        attr.core_naming = atoi(argv[2]);
        attr.core_mmap = atoi(argv[3]);
        attr.core_shm = atoi(argv[4]);
        rc = proc_setattr(pid, &attr, sizeof(procattr_t));
        if (rc) 
                {
                  printf("proc_getattr failed, errno %d\n", errno);
                  exit(-1);
                }
        bzero(&attr, sizeof(procattr_t));
        rc = proc_getattr(pid, &attr, sizeof(procattr_t));
        if (rc) 
             {
             printf("proc_getattr failed, errno %d\n", errno);
             exit(-1);
             }
        printf("core_naming %s\n", P(attr.core_naming));
        printf("core_mmap %s\n", P(attr.core_mmap));
        printf("core_shm %s\n", P(attr.core_shm));
        printf("aixthread_hrt %s\n", P(attr.aixthread_hrt));
     }   
crash64.c 
#include <stdio.h>
  int main()  
    {          
       int *p = (int *)0x100;
       pid_t pid = getpid();
       printf("My pid is %d\n", getpid());
       getchar();
       *p = 0x10;
       printf("Done\n");
  }    
# ./crash64 &  
[1]     5570566  
# My pid is 5570566    
PID 5500FC  
# ./setcoreflags 5570566 1 1 1 
core_naming ENABLE  
core_mmap ENABLE  
core_shm ENABLE  
aixthread_hrt DISABLE   
# fg  ./crash64   
Memory fault(coredump)  
# ls core*  
core.5570566.11054349