I need to find the size of a file or a directory whatever given in the commandline using stat(). It works fine for the files (both relative and absolute paths) but when I give a directory, it always returns the size as 512 or 1024.
If I print the files in the directory it goes as follows :
Name : .
Name : ..
Name : new
Name : new.c
but only the new and new.c files are actually in there. For this, the size is returned as 512 even if I place more files in the directory.
Here s my code fragment:
if (stat(request.data,&st)>=0){
request.msgType = (short)0xfe21;
printf("\n Size : %ld\n",st.st_size);
sprintf(reply.data,"%ld",st.st_size);
reply.dataLen = strlen(reply.data);
}
else{
perror("\n Stat()");
}
}
Where did I go wrong???
here is my request, reply structure:
struct message{
unsigned short msgType;
unsigned int offset;
unsigned int serverDelay;
unsigned int dataLen;
char data[100];
};
struct message request,reply;
I run it in gcc compiler in unix os.
stat() on a directory doesn't return the sum of the file sizes in it. The size field represents how much space it taken by the directory entry instead, and it varies depending on a few factors. If you want to know how much space is taken by all files below a specific directory, then you have to recurse down the tree, adding up the space taken by all files. This is how tools like du work.
Yes. opendir() + loop on readdir()/stat() will give you the file/directory sizes which you can sum to get a total. If you have sub-directories you will also have to loop on those and the files within them.
To use du you could use the system() function. This only returns a result code to the calling program so you could save the results to a file and then read the file. The code would be something like,
system("du -sb dirname > du_res_file");
Then you can read the file du_res_file (assuming it has been created successfully) to get your answer. This would give the size of the directory + sub-directories + files in one go.
Im sorry, I missed it the first time, stat only gives the size of files, not directories:
These functions return information about a file. No permissions are required on the file itself, but-in the case of stat() and lstat() - execute (search) permission is required on all of the directories in path that lead to the file.
The st_size field gives the size of the file (if it is a regular file or a symbolic link) in bytes. The size of a symbolic link is the length of the pathname it contains, without a terminating null byte.
look at the man page on fstat/stat
