/*******************************************************************************\
*				strrm.c						*
*										*
*	Streaming remove command: Remove all files and empty directories	*
*	sent in on the stdin.							*
*										*
\*******************************************************************************/
#include <stdio.h>
#include <errno.h>
#include <unistd.h>
#include <limits.h>
#include <string.h>
#include <getopt.h>
#include <libgen.h>
#include <sys/stat.h>

void	strrmUsage(char *CommandName)
{
	fprintf(stderr,"Usage: %s [--dryrun|-n] [--verbose|-v] [--help|-h]\n",CommandName) ;
	fprintf(stderr,"Remove any files or empty directories listed on the standard input\n\
	--dryrun|-n Echo the files/directories that would be deleted, but don't do the deletions.\n\
	--verbose|-v Normally strrm silently deletes, outputting only errors: this option echoes the names of files and directories being deleted.\n\
	--help|-h This help message.\n") ;
}

/*
*	strrm_error()
*
*	Print out useful error messages.  For some reason perror()'s error
*	messages aren't always helpful.
*/
static	void	strrm_error(char *String)
{
extern	int	errno ;

	switch(errno) {
		case EEXIST:
			fprintf(stderr,"%s: Directory not empty.\n",String) ;
			break ;
		default:
			perror(String) ;
	}
}

/****
*	sanitise()
*
*	Change a string so any non-printable characters are translated to their
*	octal value preceded by \.  When calling this function you should be on
*	the safe side and set the destination buffer to four times the source.
****/
static	char	*sanitise(char *SrcStr,char *DstStr)
{
	char	*StartDstStr = DstStr ;	// Keep the pointer to the start of the destination string.

	while(*SrcStr!=0) {
		if(*SrcStr<0x20 || *SrcStr>0x7E) {
			sprintf(DstStr,"\\%03o",*SrcStr++) ;
			DstStr += 4 ;
		}
		else
			*DstStr++ = *SrcStr++ ;
	}

	*DstStr = 0 ;			// Terminate the desintation string.

	return(StartDstStr) ;
}

int	main(int argc,char *argv[])
{
	int	RetVal=0,DryRun=0,Verbosity=0,ArgErr=0,Help=0 ;
	char	PathName[PATH_MAX+1],sanPathName[4*PATH_MAX+1],*fgRetVal ;
	int	optchar,shift_argc ;
	char	**shift_argv ;

	// Options descriptor
	static struct option longopts[] = {
		{"dryrun",	no_argument,	NULL,	'n' },
		{"verbose",	no_argument,	NULL,	'v' },
		{"help",	no_argument,	NULL,	'h' },
		{NULL,		0, 		NULL,	0 }
	};

	while((optchar = getopt_long(argc,argv,"nvh",longopts,NULL))!=-1) {
		switch(optchar) {
			case 'n':
				DryRun = 1 ;
				break ;
			case 'v':
				Verbosity = 1 ;
				break ;
			case 'h':
				Help = 1 ;
				break ;
			case '?':
				ArgErr = 1 ;
		}
	}

	shift_argc = argc-optind ;
	shift_argv = &argv[optind] ;	// Now the first non-opt argument will be at 0

	if(Help==1 || ArgErr==1)
		strrmUsage(argv[0]) ;
	else
		while((fgRetVal=fgets(PathName,PATH_MAX,stdin))!=0) {
			*strchr(PathName,'\n')=0 ;			// Get rid of the terminating `\n' that fgets() adds

			if(strlen(PathName)!=0) {			// Silently skip empty lines, doesn't preclude file names consisting entirely of spaces
				if(DryRun==0) {				// If it's not a dry-run then let remove() figure out the permissions
					if(remove(PathName)==-1) {	// Given the right permissions remove() will remove files and empty directories.
						strrm_error(PathName) ;
						RetVal++ ;		// Count the number of failures.
					}
					else {
						if(Verbosity==1)
							printf("%s\n",sanitise(PathName,sanPathName)) ;
					}
				}
				else {					// It's a dry run so let's do some checks before echoing the result
					struct stat StatBuf ;

					if(stat(PathName,&StatBuf)==-1)
						perror(PathName) ;
					else if(access(dirname(PathName),W_OK)!=0)
						fprintf(stderr,"The parent directory for %s is not writable\n",sanitise(PathName,sanPathName)) ;
					else
						printf("%s\n",sanitise(PathName,sanPathName)) ;
				}
			}
		}

	return(RetVal) ;						// Return count of files which could not be removed.
}

//******************************************************************************
// Change log
//
// $Log: strrm.c,v $
// Revision 2.3  2013/01/22 11:57:25  pkearns
// Improve comments and error/help messages.
//
// Revision 2.2  2013/01/21 17:12:37  pkearns
// Add new function, sanitise(), to handle the outputting of awkward
// filenames.
// Declare a new variable to hold sanitise()d strings.
// Change include file strings.h to string.h so it will compile on Linux.
// Move Usage() to the top, and rename to strrmUsage().
//
// Revision 2.1  2012/11/29 13:07:13  pkearns
// Substantial revision to introduce command line options and skip empty lines.
//
// Revision 1.1  2006/04/04 11:13:59  pkearns
// Initial revision
//