initial commit of fail

4 files changed, 270 insertions, 0 deletions

diff --git a/Makefile b/Makefile
new file mode 100644
index 0000000..7dca2f3
--- /dev/null
+++ b/Makefile
@@ -0,0 +1,23 @@
+ALL=fail
+
+CFLAGS=-g -O2 -Wall -Wno-switch -Wextra -Wwrite-strings
+
+DESTDIR=
+PREFIX=/usr/local
+BINDIR=$(PREFIX)/bin
+MANDIR=$(PREFIX)/share/man
+
+all: $(ALL)
+
+README: fail.1
+	mandoc -Tutf8 $< | col -bx >$@
+
+clean: FRC
+	rm -f $(ALL)
+
+install: FRC all
+	mkdir -p $(DESTDIR)$(BINDIR) $(DESTDIR)$(MANDIR)/man1
+	install -m0755 $(ALL) $(DESTDIR)$(BINDIR)
+	install -m0644 $(ALL:=.1) $(DESTDIR)$(MANDIR)/man1
+
+FRC:
diff --git a/README b/README
new file mode 100644
index 0000000..c0ab3f2
--- /dev/null
+++ b/README
@@ -0,0 +1,59 @@
+FAIL(1)                     General Commands Manual                    FAIL(1)
+
+NAME
+     fail – crash in various possible ways
+
+SYNOPSIS
+     fail [-123Oacdikrst]
+
+DESCRIPTION
+     fail crashes in various possible ways to help you debug how other
+     software reacts to this.
+
+     The options are as follows:
+
+     -1      Return with exit status -1.
+
+     -2      Return with exit status 2.
+
+     -3      Return with exit status 111.
+
+     -O      Allocate memory in an infinite loop, to trigger an out of memory
+             situation.  A dot is printed after each 16MB allocation.
+             Warning: this may lock up your machine and/or result in killing
+             other processes, too.  Use with caution.
+
+     -a      Call abort().
+
+     -c      Violate a seccomp() strict mode restriction.
+
+     -d      Divide by zero.
+
+     -i      Execute an illegal instruction.
+
+     -k      Raise SIGKILL.
+
+     -r      Trigger an infinite recursion.
+
+     -s      Trigger a segmentation fault by writing to a null pointer.
+
+     -t      Trigger GCC's __builtin_trap().
+
+EXIT STATUS
+     The fail utility never returns 0, because failure is inevitable.
+
+SEE ALSO
+     false(1), seccomp(2), abort(3)
+
+AUTHORS
+     Leah Neukirchen <leah@vuxu.org>
+
+LICENSE
+     fail is in the public domain.
+
+     To the extent possible under law, the creator of this work has waived all
+     copyright and related or neighboring rights to this work.
+
+     http://creativecommons.org/publicdomain/zero/1.0/
+
+Void Linux                       July 14, 2017                      Void Linux
diff --git a/fail.1 b/fail.1
new file mode 100644
index 0000000..c47fbd5
--- /dev/null
+++ b/fail.1
@@ -0,0 +1,72 @@
+.Dd July 14, 2017
+.Dt FAIL 1
+.Os
+.Sh NAME
+.Nm fail
+.Nd crash in various possible ways
+.Sh SYNOPSIS
+.Nm
+.Op Fl 123Oacdikrst
+.Sh DESCRIPTION
+.Nm
+crashes in various possible ways to
+help you debug how other software reacts to this.
+.Pp
+The options are as follows:
+.Bl -tag -width Ds
+.It Fl 1
+Return with exit status -1.
+.It Fl 2
+Return with exit status 2.
+.It Fl 3
+Return with exit status 111.
+.It Fl O
+Allocate memory in an infinite loop,
+to trigger an out of memory situation.
+A dot is printed after each 16MB allocation.
+.Sy Warning :
+this may lock up your machine
+and/or result in killing other processes, too.
+Use with caution.
+.It Fl a
+Call
+.Fn abort .
+.It Fl c
+Violate a
+.Fn seccomp
+strict mode restriction.
+.It Fl d
+Divide by zero.
+.It Fl i
+Execute an illegal instruction.
+.It Fl k
+Raise SIGKILL.
+.It Fl r
+Trigger an infinite recursion.
+.It Fl s
+Trigger a segmentation fault by writing to a null pointer.
+.It Fl t
+Trigger GCC's
+.Fn __builtin_trap .
+.El
+.Sh EXIT STATUS
+The
+.Nm
+utility never returns 0,
+because failure is inevitable.
+.Sh SEE ALSO
+.Xr false 1 ,
+.Xr seccomp 2 ,
+.Xr abort 3
+.Sh AUTHORS
+.An Leah Neukirchen Aq Mt leah@vuxu.org
+.Sh LICENSE
+.Nm
+is in the public domain.
+.Pp
+To the extent possible under law,
+the creator of this work
+has waived all copyright and related or
+neighboring rights to this work.
+.Pp
+.Lk http://creativecommons.org/publicdomain/zero/1.0/
diff --git a/fail.c b/fail.c
new file mode 100644
index 0000000..36896c5
--- /dev/null
+++ b/fail.c
@@ -0,0 +1,116 @@
+/* fail - crash in various possible ways */
+
+#include <linux/seccomp.h>
+
+#include <sys/prctl.h>
+#include <sys/ptrace.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+
+#include <fcntl.h>
+#include <signal.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+void
+segfault() {
+	volatile int *nullp = 0;
+
+	*nullp = 42;
+}
+
+// can lockup your machine
+void
+oom() {
+	long c = 0;
+	static long last = 0;
+
+	int fd;
+	fd = open("/proc/self/oom_score_adj", O_WRONLY);
+	write(fd, "1000\n", 5);
+	close(fd);
+
+	while (1) {
+		long *m = malloc(4096*4096);
+		m[0] = last;
+		m[1] = c++;
+		last = (long)m;
+		write(1, ".", 1);
+	}
+}
+
+void
+recurse(char *n) {
+	char m[1024];
+	recurse(m);
+	if (n)
+		m[0] = n[0] = 42;
+}
+
+void
+abortme() {
+	abort();
+}
+
+void
+killme() {
+	raise(SIGKILL);
+}
+
+void illegalins() {
+#if defined(__x86_64__) || defined(__i386__)
+        __asm__ __volatile__( "ud1" : : : "memory" );
+#elif defined(__arm__)
+        __asm__ __volatile__(
+	#ifndef __thumb__
+		".word 0xe7f000f0"
+	#else
+		".short 0xdeff"
+	#endif
+                : : : "memory");
+#elif defined(__aarch64__)
+	__asm__ __volatile__( ".word 0x00800011" : : : "memory" );
+#else
+	#error implement illegalins for this architecture
+#endif
+}
+
+void trap() {
+	__builtin_trap();
+}
+
+int zero = 0;
+void divtrap() {
+	zero = 1/zero;
+}
+
+void
+violate_seccomp() {
+	prctl(PR_SET_SECCOMP, SECCOMP_MODE_STRICT);
+	chdir("/");
+}
+
+int
+main(int argc, char *argv[]) {
+	int c;
+
+	while ((c = getopt(argc, argv, "123Oacdikrst")) != -1) {
+        	switch (c) {
+		case '1': exit(-1); break;
+		case '2': exit(2); break;
+		case '3': exit(111); break;
+                case 'c': violate_seccomp(); break;
+		case 'd': divtrap(); break;
+		case 'i': illegalins(); break;
+		case 't': trap(); break;
+                case 'O': oom(); break;
+                case 'a': abortme(); break;
+                case 'k': killme(); break;
+                case 'r': recurse(0); break;
+                case 's': segfault(); break;                
+		}
+        }
+
+	write(2, "Usage: fail [-123Oacdikrst]", 8);
+	exit(1);
+}