write and read processes

[michellia]

The other thread was closed so I need to start this one.
This code from witchcraft


#ifndef __cplusplus
#define _GNU_SOURCE
#endif


#include <unistd.h>
#include <dirent.h>
#include <sys/types.h> // for opendir(), readdir(), closedir()
#include <sys/stat.h> // for stat()


#ifdef __cplusplus
#include <iostream>
#include <cstdlib>
#include <cstring>
#include <cstdarg>
#else
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <stdarg.h>
#endif




#define PROC_DIRECTORY "/proc/"
#define CASE_SENSITIVE 1
#define CASE_INSENSITIVE 0
#define EXACT_MATCH 1
#define INEXACT_MATCH 0




int IsNumeric(const char* ccharptr_CharacterList)
{
for ( ; *ccharptr_CharacterList; ccharptr_CharacterList++)
if (*ccharptr_CharacterList < '0' || *ccharptr_CharacterList > '9')
return 0; // false
return 1; // true
}




int strcmp_Wrapper(const char *s1, const char *s2, int intCaseSensitive)
{
if (intCaseSensitive)
return !strcmp(s1, s2);
else
return !strcasecmp(s1, s2);
}


int strstr_Wrapper(const char* haystack, const char* needle, int intCaseSensitive)
{
if (intCaseSensitive)
return (int) strstr(haystack, needle);
else
return (int) strcasestr(haystack, needle);
}




#ifdef __cplusplus
pid_t GetPIDbyName(const char* cchrptr_ProcessName, int intCaseSensitiveness, int intExactMatch)
#else
pid_t GetPIDbyName_implements(const char* cchrptr_ProcessName, int intCaseSensitiveness, int intExactMatch)
#endif
{
char chrarry_CommandLinePath[100] ;
char chrarry_NameOfProcess[300] ;
char* chrptr_StringToCompare = NULL ;
pid_t pid_ProcessIdentifier = (pid_t) -1 ;
struct dirent* de_DirEntity = NULL ;
DIR* dir_proc = NULL ;


int (*CompareFunction) (const char*, const char*, int) ;


if (intExactMatch)
CompareFunction = &strcmp_Wrapper;
else
CompareFunction = &strstr_Wrapper;




dir_proc = opendir(PROC_DIRECTORY) ;
if (dir_proc == NULL)
{
perror("Couldn't open the " PROC_DIRECTORY " directory") ;
return (pid_t) -2 ;
}


// Loop while not NULL
while ( (de_DirEntity = readdir(dir_proc)) )
{
if (de_DirEntity->d_type == DT_DIR)
{
if (IsNumeric(de_DirEntity->d_name))
{
strcpy(chrarry_CommandLinePath, PROC_DIRECTORY) ;
strcat(chrarry_CommandLinePath, de_DirEntity->d_name) ;
strcat(chrarry_CommandLinePath, "/cmdline") ;
FILE* fd_CmdLineFile = fopen (chrarry_CommandLinePath, "rt") ; // open the file for reading text
if (fd_CmdLineFile)
{
fscanf(fd_CmdLineFile, "%s", chrarry_NameOfProcess) ; // read from /proc/<NR>/cmdline
fclose(fd_CmdLineFile); // close the file prior to exiting the routine


if (strrchr(chrarry_NameOfProcess, '/'))
chrptr_StringToCompare = strrchr(chrarry_NameOfProcess, '/') +1 ;
else
chrptr_StringToCompare = chrarry_NameOfProcess ;


//printf("Process name: %s\n", chrarry_NameOfProcess);
//printf("Pure Process name: %s\n", chrptr_StringToCompare );


if ( CompareFunction(chrptr_StringToCompare, cchrptr_ProcessName, intCaseSensitiveness) )
{
pid_ProcessIdentifier = (pid_t) atoi(de_DirEntity->d_name) ;
closedir(dir_proc) ;
return pid_ProcessIdentifier ;
}
}
}
}
}
closedir(dir_proc) ;
return pid_ProcessIdentifier ;
}


#ifdef __cplusplus
pid_t GetPIDbyName(const char* cchrptr_ProcessName)
{
return GetPIDbyName(cchrptr_ProcessName, CASE_INSENSITIVE, EXACT_MATCH) ;
}
#else
// C cannot overload functions - fixed
pid_t GetPIDbyName_Wrapper(const char* cchrptr_ProcessName, ... )
{
int intTempArgument ;
int intInputArguments[2] ;
// intInputArguments[0] = 0 ;
// intInputArguments[1] = 0 ;
memset(intInputArguments, 0, sizeof(intInputArguments) ) ;
int intInputIndex ;
va_list argptr;


va_start( argptr, cchrptr_ProcessName );
for (intInputIndex = 0; (intTempArgument = va_arg( argptr, int )) != 15; ++intInputIndex)
{
intInputArguments[intInputIndex] = intTempArgument ;
}
va_end( argptr );
return GetPIDbyName_implements(cchrptr_ProcessName, intInputArguments[0], intInputArguments[1]);
}


#define GetPIDbyName(ProcessName,...) GetPIDbyName_Wrapper(ProcessName, ##__VA_ARGS__, (int) 15)


#endif


int main()
{
pid_t pid = GetPIDbyName("bash") ; // If -1 = not found, if -2 = proc fs access error
printf("PID %d\n", pid);
return EXIT_SUCCESS ;
}




My problem is I start a process called "directory" this function cannot see this process. When I do a manual "ps aux" I see the process. I can get it
to see processes like bash and firefox but not something else I started. Even though it is running. I even run the code 4 times and have four "directory"
processes running and it does not see them.

any suggestions.

[trent.josephsen]

What happened to all the newlines?

[michellia]

new lines are back, seems this editor/website does not like html formatiing

[michellia]

seems with more research we need this code to see kernel threads. the process we started called "directory" comes out in square brackets with the
ps command
[directory]