smemcap.c modify to return /proc/[pid]/* as string

smemcap.c

/*
 smem - a tool for meaningful memory reporting

 Copyright 2008-2009 Matt Mackall <mpm@selenic.com>
 Copyright 2016 Kien Truong <duckientruong@gmail.com>

 This software may be used and distributed according to the terms of
 the GNU General Public License version 2 or later, incorporated
 herein by reference.
*/

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/stat.h>
#include <memory.h>
#include <errno.h>
#include <fcntl.h>
#include <dirent.h>

struct fileblock;
struct fileblock {
	char data[512];
	struct fileblock *next;
};

int readProcFile(const char *path, char** ret)
{
	struct fileblock *start, *cur;
	struct fileblock **prev = &start;
	int fd, r, size = 0;

	/* buffer and stat the file */
	fd = open(path, O_RDONLY);
	if (fd == -1) {
		return -1;
	}

	do {
		cur = calloc(1, sizeof(struct fileblock));
		*prev = cur;
		prev = &cur->next;
		r = read(fd, cur->data, 512);
		if (r > 0)
			size += r;
	} while (r == 512);

	close(fd);

	char* content = (char*) malloc(size + 1);
	int old_size = size;
	if (content) {
		int counter = 0;
		/* dump file contents */
		for (cur = start; size > 0; size -= 512) {
			if (size > 512) {
				memcpy(content + counter * 512, cur->data, 512);	
			} else {
				memcpy(content + counter * 512, cur->data, size);	
			}
			start = cur;
			cur = cur->next;
			free(start);
			counter++;
		}	
		content[old_size] = '\0';
		*ret = content;
		return 0;
	} else {
		return -1;
	}
}

int readProcDir(const char *sub, const char *name)
{
	char path[256];
	sprintf(path, "%s/%s", sub, name);
	char** content = malloc(sizeof(char*));
	int ret = readProcFile(path, content);
	if (ret == 0) {
		printf("File: %s\n", path);
		printf("Content: %s\n", *content);
		free(*content);
	}
	free(content);
	return 0;
}

int main(int argc, char *argv[])
{
	DIR *d;
	struct dirent *de;

	chdir("/proc");

	d = opendir(".");
	while ((de = readdir(d)))
		if (de->d_name[0] >= '0' && de->d_name[0] <= '9') {
			readProcDir(de->d_name, "smaps");
			readProcDir(de->d_name, "cmdline");
			readProcDir(de->d_name, "stat");
		}

	return 0;
}