proc.c

#include <stdio.h>
#include <string.h>
#include <unistd.h>

#include <dirent.h>
#include <time.h>

#include <sys/stat.h>
#include <sys/types.h>

void get_command_line(int pid, char * out)
{
	char path[256];
	FILE* fp;

	sprintf(path, "/proc/%d/cmdline", pid);		// build up cmdline path

	fp = fopen(path, "r");
	if(!fp) return;

	fgets(out, 256, fp);							// we only need to read just one line
	fclose(fp);
}

int get_vmsize(int pid)
{
	char path[256];
	char line[256];
	FILE* fp;
	int size;

	sprintf(path, "/proc/%d/status", pid);

	fp = fopen(path, "r");
	if(!fp) return;

	while(fgets(line, 256, fp) != NULL)
	{
		if(strstr(line, "VmSize:"))
		{
			sscanf(line, "VmSize:%d", &size);
			break;
		}
	}

	fclose(fp);

	return size;
}


int main() 
{
	DIR* dir; 				// DIR pointer which points /proc
	struct dirent* entry;	// DIRectory ENTry

	int pid; 				// process pid
	int vmSize = 0;
	char cmdLine	[256];		// command line

	dir = opendir("/proc");

	// for each entry of dir
	while( (entry = readdir(dir)) != NULL ) 
	{
		char 		path[256];
		struct stat fileStat;	// has each file info

		sprintf(path, "/proc/%s", entry->d_name);
		lstat(path, &fileStat);		// retriving entry's stat

		if(!S_ISDIR(fileStat.st_mode))		// if this entry is not a directory then
		{
			continue;						// we don't need this
		}

		pid = atoi(entry->d_name);			// get pid from filename
		if( pid < 0 ) continue;				// if pid is not a number then ignore

		get_command_line(pid, cmdLine);	// retrive cmdline
		vmSize = get_vmsize(pid);

		//printf("[pid : %d]\t[size : %d]\t[creation time : %d]\t%s\n", pid, vmSize, fileStat.st_ctime, cmdLine);
		printf("[%d] \n%s%s%s\n", 
			pid,
			ctime(&fileStat.st_atime),  // last access
			ctime(&fileStat.st_mtime),  // last modif
			ctime(&fileStat.st_ctime)	// last creation
		);
	}

	closedir(dir);
}