dirname.c

/***********************************************************************
*                                                                      *
*               This software is part of the ast package               *
*          Copyright (c) 1992-2012 AT&T Intellectual Property          *
*          Copyright (c) 2020-2024 Contributors to ksh 93u+m           *
*                      and is licensed under the                       *
*                 Eclipse Public License, Version 2.0                  *
*                                                                      *
*                A copy of the License is available at                 *
*      https://www.eclipse.org/org/documents/epl-2.0/EPL-2.0.html      *
*         (with md5 checksum 84283fa8859daf213bdda5a9f8d1be1d)         *
*                                                                      *
*                 Glenn Fowler <gsf@research.att.com>                  *
*                  David Korn <dgk@research.att.com>                   *
*                  Martijn Dekker <martijn@inlv.org>                   *
*            Johnothan King <johnothanking@protonmail.com>             *
*             dnewhall <dnewhall@users.noreply.github.com>             *
*                                                                      *
***********************************************************************/
/*
 * David Korn
 * AT&T Bell Laboratories
 *
 * dirname path [suffix]
 *
 * print the dirname of a pathname
 */

static const char usage[] =
"[-?\n@(#)$Id: dirname (ksh 93u+m) 2024-12-25 $\n]"
"[--catalog?" ERROR_CATALOG "]"
"[+NAME?dirname - return directory portion of file name]"
"[+DESCRIPTION?\bdirname\b treats each \astring\a as a file name and outputs "
	"the name of the directory containing the file name by deleting "
	"the last component from \astring\a.]"
"[+?If \astring\a consists solely of \b/\b characters the output will "
	"be a single \b/\b unless \bPATH_LEADING_SLASHES\b returned by "
	"\bgetconf\b(1) is \b1\b and \astring\a consists of multiple "
	"\b/\b characters in which case \b//\b will be output.  "
	"Otherwise, trailing \b/\b characters are removed, and if "
	"there are no remaining \b/\b characters in \astring\a, "
	"the string \b.\b will be written to standard output.  "
	"Otherwise, all characters following the last \b/\b are removed. "
	"If the remaining string consists solely of \b/\b characters, "
	"the output will be as if the original string had consisted solely "
	"as \b/\b characters as described above.  Otherwise, all "
	"trailing slashes are removed and the output will be this string "
	"unless this string is empty.  If empty the output will be \b.\b.]"
"[f:file?Print the \b$PATH\b relative regular file path for \astring\a.]"
"[r:relative?Print the \b$PATH\b relative readable file path for \astring\a.]"
"[x:executable?Print the \b$PATH\b relative executable file path for \astring\a.]"
"[z:zero?Each line of output is terminated with a NUL character instead "
    "of a newline.]"
"\n"
"\nstring ...\n"
"\n"
"[+EXIT STATUS?]{"
	"[+0?Successful completion.]"
	"[+>0?An error occurred.]"
"}"
"[+SEE ALSO?\bbasename\b(1), \bgetconf\b(1), \bdirname\b(3), \bpathname\b(3)]"
;

#include <cmd.h>

static void l_dirname(Sfio_t *outfile, const char *pathname, char termch)
{
	const char  *last;
	/* go to end of path */
	for(last=pathname; *last; last++);
	/* back over trailing '/' */
	while(last>pathname && *--last=='/');
	/* back over non-slash chars */
	for(;last>pathname && *last!='/';last--);
	if(last==pathname)
	{
		/* all '/' or "" */
		if(*pathname!='/')
			last = pathname = ".";
	}
	else
	{
		/* back over trailing '/' */
		for(;*last=='/' && last > pathname; last--);
	}
	/* preserve leading '//' */
	if(last==pathname && pathname[0]=='/')
		while(last[1]=='/')
			last++;
	if(last!=pathname && pathname[0]=='/' && pathname[1]=='/')
	{
		/* skip any '/' until last two */
		while(pathname[2]=='/' && pathname<last)
			pathname++;
		/* skip first '/' if PATH_LEADING_SLASHES not set */
		if(last!=pathname && pathname[0]=='/' && pathname[1]=='/' && *astconf("PATH_LEADING_SLASHES",NULL,NULL)!='1')
			pathname++;
	}
	sfwrite(outfile,pathname,last+1-pathname);
	sfputc(outfile,termch);
}

int
b_dirname(int argc, char** argv, Shbltin_t* context)
{
	int	mode = 0;
	char	buf[PATH_MAX];
	char	termch = '\n';

	cmdinit(argc, argv, context, ERROR_CATALOG, 0);
	for (;;)
	{
		switch (optget(argv, usage))
		{
		case 'f':
			mode |= PATH_REGULAR;
			continue;
		case 'r':
			mode &= ~PATH_REGULAR;
			mode |= PATH_READ;
			continue;
		case 'x':
			mode |= PATH_EXECUTE;
			continue;
		case 'z':
			termch = '\0';
			continue;
		case ':':
			error(2, "%s", opt_info.arg);
			break;
		case '?':
			error(ERROR_usage(2), "%s", opt_info.arg);
			UNREACHABLE();
		}
		break;
	}
	argv += opt_info.index;
	argc -= opt_info.index;
	if(error_info.errors || argc < 1)
	{
		error(ERROR_usage(2),"%s", optusage(NULL));
		UNREACHABLE();
	}
	for(; argv[0]; argv++)
	{
		if(!mode)
			l_dirname(sfstdout,argv[0],termch);
		else if(pathpath(argv[0], "", mode, buf, sizeof(buf)))
			sfputr(sfstdout, buf, termch);
		else
			error(1|ERROR_WARNING, "%s: relative path not found", argv[0]);
	}
	return 0;
}