gistfile1.txt

/*
Tool for computing partman partition sizes
Based on partman docs at https://wikitech.wikimedia.org/wiki/PartManAuto

To compile: gcc partman-check.c -o partman-check
To run: ./partman-check

*/

#include <stddef.h>
#include <stdio.h>
#include <stdlib.h>

#define BUFFER_SIZE 80

typedef struct PARTITION
{
	int min;
	int max;
	int priority;


}Partition;

int read_int(char* prompt)
{

	int result;
	char content[BUFFER_SIZE];

	printf("%s\n>",prompt);
	fgets(content, BUFFER_SIZE, stdin);
	
	sscanf(content, "%i", &result);
	return result;
	

}

int main( int argc, char** argv)
{

	int i = 0;
	int N; // number of partitions
	int free_space; // total size of disk
	Partition* partitions;
	
	printf("For help, please see https://wikitech.wikimedia.org/wiki/PartManAuto\n");

	
	N = read_int("How many partitions to configure?");
	free_space = read_int("How much free space is there on disk? (in MB)");
	
	partitions = malloc (sizeof(Partition) * N);
	int factor[N];

	for (i = 0; i < N; i++)
	{
		printf("Configuring partition %i of %i\n",i+1,N);
		partitions[i].min = read_int("\tMin size for partition (in MB)");
		partitions[i].max = read_int("\tMax size for partition (in MB)");
		partitions[i].priority = read_int("\tPartition priority (see documentation).") ;

	}


	for(i=0;i<=N;i++) 
	   factor[i] = partitions[i].priority - partitions[i].min;

	int ready = 0;
	while (! ready) {
		int minsum = 0; 
		int factsum = 0;

		for (i = 0; i<N; i++)
			minsum += partitions[i].min;

		for (i = 0; i<N; i++)
			factsum += factor[i];


		ready = 1;

		for(i=0;i<N;i++) {
		
			float scale = (float) factor[i] / (float) factsum;
			float step = ( (float)free_space - (float)minsum) * scale ;
			int x = partitions[i].min  + (int)step;
			if (x > partitions[i].max)
				x = partitions[i].max;
			if (x != partitions[i].min) {
				ready = 0;
				partitions[i].min = x;
			}

		}
	}


	for (i = 0; i < N; i++)
		printf("Partition %i: %i \n",i+1,partitions[i].min);
}