C - Obtaining directory path - c

Question

I'm writing a program that when executed in a directory will generate a text file with all of the contents in that directory. I'm getting the directory path from the **argv to main and because I'm using netbeans and cygwin I have to do some string manipulation of the obtained path in my char* get_path(char **argv) function. The directory path size will always vary therefore I'm assigning space with malloc to store it in the memory.
Program snippet:
#include <stdio.h>
#include <stdlib.h>
#include <dirent.h>
#include "dbuffer.h" //my own library
#include "darray.h" //my own library
ARR* get_dir_contents( char* path)
{
DBUFF *buff = NULL;
ARR *car = NULL;
DIR *dir_stream = NULL;
struct dirent *entry = NULL;
dir_stream = opendir(path);
if(opendir(path)==NULL) printf("NULL");
//... more code here
return car;
}
char* get_path(char **argv)
{
char *path = malloc(sizeof(char)* sizeof_pArray( &argv[0][11] ) + 3 );
strcpy(path, "C:");
strcat(path, &argv[0][11]);
printf("%s, sizeof: %d \n",path, sizeof_pArray(path));
return path;
}
int main(int argc, char** argv)
{
char *p = get_path(argv);
ARR *car = get_dir_contents(&p[0]);
//... more code here
return (EXIT_SUCCESS);
}
The problem is that the string that I have doesn't initialize the dir_stream pointer. I suspect it is because of some discrepancy between pointers and string literals but I can't pinpoint what it is exactly. Also the fact that dirent library function expects DIR *opendir(const char *dirname); const char might have something to do with it.
Output:
C:/Users/uk676643/Documents/NetBeansProjects/__OpenDirectoryAndListFiles/dist/Debug/Cygwin_4.x-Windows/__opendirectoryandlistfiles, sizeof: 131
NULL
RUN FAILED (exit value -1,073,741,819, total time: 2s)

Answer 1

there are some things here that can go wrong so
I would suggest doing something like this instead
char* get_path(char *argv)
{
char *path = malloc(sizeof(char)* strlen(argv) );
if (path != NULL)
{
strcpy(path, "C:");
strcat(path, argv + 11);
printf("%s, sizeof: %d \n",path, strlen(path));
}
return path;
}
...
char* p = get_path(*argv);
note: you don't need the extra 3 bytes, since you allocate including the 11 bytes you later skip. although instead of having the 11 bytes offset you may want to decompose the string and then later put it together so that it is portable. E.g. using strtok you could split that path and replace the parts you don't need.

Answer 2

Could it be a simple confusion about argv ? Please insert the following lines
just at the beginning of your main() , is it what you expected ?
printf("\n argv[0]== %s" , argv[0] );
getchar();
printf("\n argv[1]== %s" , argv[1] );
getchar();
OK, so we work from argv[0] , please try this for get_path
char *get_path(char *argv)
{
int i=0;
// +2 to add the drive letter
char *path = malloc(sizeof(char)* strlen(argv)+2 );
if (path != NULL)
{
strcpy(path, "C:");
strcat(path, argv);
// we get the path and the name of calling program
printf("\n path and program== %s",path);
printf("%s, sizeof: %d \n",path, strlen(path));
// now remove calling program name
for( i=strlen(path) ; ; i--)
{
// we are working in windows
if(path[i]=='\\') break;
path[i]='\0';
}
}
return path;
}