From d0e7d6f6d6ff4d599b55b27f7c066f6c7d8f578f Mon Sep 17 00:00:00 2001

From: Alexey Gladkov <legion@altlinux.org>

Date: Wed, 4 Aug 2021 10:07:16 +0200

Subject: Implement losetup as builtin

Signed-off-by: Alexey Gladkov <legion@altlinux.org>

---

 src/Makefile.am     |  2 +-

 src/bltin/losetup.c | 87 +++++++++++++++++++++++++++++++++++++++++++++

 src/builtins.def.in |  1 +

 3 files changed, 89 insertions(+), 1 deletion(-)

 create mode 100644 src/bltin/losetup.c

diff --git a/src/Makefile.am b/src/Makefile.am

index 1732465..85e1098 100644

--- a/src/Makefile.am

+++ b/src/Makefile.am

@@ -20,7 +20,7 @@ dash_CFILES = \

 	alias.c arith_yacc.c arith_yylex.c cd.c error.c eval.c exec.c expand.c \

 	histedit.c input.c jobs.c mail.c main.c memalloc.c miscbltin.c \

 	mystring.c options.c parser.c redir.c show.c trap.c output.c \

-	bltin/printf.c system.c bltin/test.c bltin/times.c var.c

+	bltin/printf.c system.c bltin/test.c bltin/times.c bltin/losetup.c var.c

 dash_SOURCES = \

 	$(dash_CFILES) \

 	alias.h arith_yacc.h bltin/bltin.h cd.h error.h eval.h exec.h \

diff --git a/src/bltin/losetup.c b/src/bltin/losetup.c

new file mode 100644

index 0000000..84d4a70

--- /dev/null

+++ b/src/bltin/losetup.c

@@ -0,0 +1,87 @@

+/*

+ * Losetup command.

+ */

+

+#define main losetupcmd

+

+#ifdef USE_GLIBC_STDIO

+#include <stdio.h>

+

+#include "../mystring.h"

+#else

+#include "bltin.h"

+#endif

+

+#include <unistd.h>

+#include <errno.h>

+#include <fcntl.h>

+#include <sys/ioctl.h>

+

+#ifndef	dev_t

+#define	dev_t	dev_t

+#endif

+#include <linux/loop.h>

+

+int

+main(int argc, const char *const *argv)

+{

+	int loopfd, targfd;

+	struct loop_info loopInfo;

+

+	if ( argc < 3 )

+		return 1;

+

+	if ( !strcmp( argv[1], "-d" ) )

+	{

+		loopfd = open( argv[2], O_RDONLY );

+		if ( loopfd < 0 )

+		{

+			fprintf( stderr, "losetup: error opening %s: %s\n", argv[2], strerror(errno) );

+			return 1;

+		}

+

+		if ( ioctl(loopfd, LOOP_CLR_FD, 0) < 0 )

+		{

+			fprintf( stderr, "losetup: error unassociating device: %s\n", strerror(errno) );

+			close( loopfd );

+			return 1;

+		}

+

+		close( loopfd );

+		return 0;

+	}

+

+	loopfd = open( argv[1], O_RDONLY );

+	if ( loopfd < 0 )

+	{

+		fprintf( stderr, "losetup: error opening %s: %s\n", argv[1], strerror(errno) );

+		return 1;

+	}

+

+	targfd = open( argv[2], O_RDONLY );

+	if ( targfd < 0 )

+	{

+		fprintf( stderr, "losetup: error opening %s: %s\n", argv[2], strerror(errno) );

+		close( loopfd );

+		return 1;

+	}

+

+	if ( ioctl(loopfd, LOOP_SET_FD, targfd) < 0 )

+	{

+		fprintf( stderr, "losetup: error setting up loopback device: %s\n", strerror(errno) );

+		close( loopfd );

+		close( targfd );

+		return 1;

+	}

+

+	memset(&loopInfo, 0, sizeof(loopInfo));

+	strcpy(loopInfo.lo_name, argv[2]);

+

+	if ( ioctl(loopfd, LOOP_SET_STATUS, &loopInfo) < 0 )

+		fprintf( stderr, "losetup: error setting up loopback device: %s\n", strerror(errno) );

+

+	close( loopfd );

+	close( targfd );

+

+	return 0;

+}

diff --git a/src/builtins.def.in b/src/builtins.def.in

index 95e420c..87f0476 100644

--- a/src/builtins.def.in

+++ b/src/builtins.def.in

@@ -92,3 +92,4 @@ ulimitcmd	-u ulimit

 #endif

 testcmd		test [

 killcmd		-u kill

+losetupcmd	losetup

-- 

2.29.3