How to check if a file is in given directory - c

Question

I tried to search that in many words, but for some reason I am solely given references to questions like "How to check if file or directory exists".
Instead, I would like to check if a given file is located in a given directory.
The problem is that the file, the directory or both can and sometimes have to be passed as a relative path, instead of absolute path.
Is there any windows/unix function that checks on that?

Answer 1

here is an example of using the stat() function regardless if the 'filename' is a full path or just the file name
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <stdbool.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#if 0
struct stat {
dev_t st_dev; /* ID of device containing file */
ino_t st_ino; /* Inode number */
mode_t st_mode; /* File type and mode */
nlink_t st_nlink; /* Number of hard links */
uid_t st_uid; /* User ID of owner */
gid_t st_gid; /* Group ID of owner */
dev_t st_rdev; /* Device ID (if special file) */
off_t st_size; /* Total size, in bytes */
blksize_t st_blksize; /* Block size for filesystem I/O */
blkcnt_t st_blocks; /* Number of 512B blocks allocated */
/* Since Linux 2.6, the kernel supports nanosecond
precision for the following timestamp fields.
For the details before Linux 2.6, see NOTES. */
struct timespec st_atim; /* Time of last access */
struct timespec st_mtim; /* Time of last modification */
struct timespec st_ctim; /* Time of last status change */
#define st_atime st_atim.tv_sec /* Backward compatibility */
#define st_mtime st_mtim.tv_sec
#define st_ctime st_ctim.tv_sec
};
#endif
bool doesFileExistInDir( char *path, char *filename )
{
struct stat myStat;
int statStatus;
char pathname[ strlen(path) + strlen( filename ) + 1];
if( !strchr( filename, '/' ) )
{
pathname[0] = '\0';
strcat( pathname, path );
// strcat( pathname, "/" );
strcat( pathname, filename );
}
else
{
strcpy( pathname, filename );
}
if( (statStatus = stat( pathname, &myStat )) != 0 )
{
// then file not accessible -or- directory not readable -or- file does not exist
perror( "stat failed" );
return false;
}
return true;
}

Answer 2

This function can be used to determine if dirname is the directory of filename.
int file_is_in_directory (char *filename, char *dirname) /* [!] Windows-specific */
{
char filename_full[MAX_PATH] = {'\0'};
char dirname_full[MAX_PATH] = {'\0'};
char* file = NULL;
GetFullPathNameA(filename, MAX_PATH, filename_full, NULL); /* [!] Check rval */
GetFullPathNameA(dirname, MAX_PATH, dirname_full, NULL); /* [!] Check rval */
if(!strncmp(dirname_full, filename_full, strlen(dirname_full)))
{
return 1; /* File is located in directory */
}
return 0; /* File not contained */
}