Moved intercept code to a library module to allow it to be used by

test/bbackupd as well (refs #3)

1 files changed, 315 insertions, 0 deletions

diff --git a/lib/intercept/intercept.cpp b/lib/intercept/intercept.cpp
new file mode 100644
index 00000000..4f8ef785
--- /dev/null
+++ b/lib/intercept/intercept.cpp
@@ -0,0 +1,315 @@
+// --------------------------------------------------------------------------
+//
+// File
+//		Name:    intercept.cpp
+//		Purpose: Syscall interception code for the raidfile test
+//		Created: 2003/07/22
+//
+// --------------------------------------------------------------------------
+
+#include "Box.h"
+
+#ifdef HAVE_SYS_SYSCALL_H
+	#include <sys/syscall.h>
+#endif
+#include <sys/types.h>
+#include <unistd.h>
+
+#ifdef HAVE_SYS_UIO_H
+#include <sys/uio.h>
+#endif
+
+#include <errno.h>
+
+#ifndef PLATFORM_CLIB_FNS_INTERCEPTION_IMPOSSIBLE
+
+#if !defined(HAVE_SYSCALL) && !defined(HAVE___SYSCALL) && !defined(HAVE___SYSCALL_NEED_DEFN)
+	#define PLATFORM_NO_SYSCALL
+#endif
+
+#ifdef PLATFORM_NO_SYSCALL
+	// For some reason, syscall just doesn't work on Darwin
+	// so instead, we build functions using assembler in a varient
+	// of the technique used in the Darwin Libc
+	extern "C" int
+	TEST_open(const char *path, int flags, mode_t mode);
+	extern "C" int
+	TEST_close(int d);
+	extern "C" ssize_t
+	TEST_write(int d, const void *buf, size_t nbytes);
+	extern "C" ssize_t
+	TEST_read(int d, void *buf, size_t nbytes);
+	extern "C" ssize_t
+	TEST_readv(int d, const struct iovec *iov, int iovcnt);
+	extern "C" off_t
+	TEST_lseek(int fildes, off_t offset, int whence);
+#else
+	#ifdef HAVE___SYSCALL_NEED_DEFN
+		// Need this, not declared in syscall.h nor unistd.h
+		extern "C" off_t __syscall(quad_t number, ...);
+	#endif
+	#ifndef HAVE_SYSCALL
+		#undef syscall
+		#define syscall __syscall
+	#endif
+#endif
+
+#include <string.h>
+#include <stdio.h>
+
+#include "MemLeakFindOn.h"
+
+bool intercept_enabled = false;
+const char *intercept_filename = 0;
+int intercept_filedes = -1;
+off_t intercept_errorafter = 0;
+int intercept_errno = 0;
+int intercept_syscall = 0;
+off_t intercept_filepos = 0;
+int intercept_delay_ms = 0;
+
+#define SIZE_ALWAYS_ERROR	-773
+
+void intercept_clear_setup()
+{
+	intercept_enabled = false;
+	intercept_filename = 0;
+	intercept_filedes = -1;
+	intercept_errorafter = 0;
+	intercept_syscall = 0;
+	intercept_filepos = 0;
+	intercept_delay_ms = 0;
+}
+
+bool intercept_triggered()
+{
+	return !intercept_enabled;
+}
+
+void intercept_setup_error(const char *filename, unsigned int errorafter, int errortoreturn, int syscalltoerror)
+{
+	TRACE4("Setup for error: %s, after %d, err %d, syscall %d\n", filename, errorafter, errortoreturn, syscalltoerror);
+	intercept_enabled = true;
+	intercept_filename = filename;
+	intercept_filedes = -1;
+	intercept_errorafter = errorafter;
+	intercept_syscall = syscalltoerror;
+	intercept_errno = errortoreturn;
+	intercept_filepos = 0;
+	intercept_delay_ms = 0;
+}
+
+void intercept_setup_delay(const char *filename, unsigned int delay_after, 
+	int delay_ms, int syscall_to_delay)
+{
+	TRACE4("Setup for delay: %s, after %d, wait %d ms, syscall %d\n", 
+		filename, delay_after, delay_ms, syscall_to_delay);
+	intercept_enabled = true;
+	intercept_filename = filename;
+	intercept_filedes = -1;
+	intercept_errorafter = delay_after;
+	intercept_syscall = syscall_to_delay;
+	intercept_errno = 0;
+	intercept_filepos = 0;
+	intercept_delay_ms = delay_ms;
+}
+bool intercept_errornow(int d, int size, int syscallnum)
+{
+	if(intercept_filedes != -1 && d == intercept_filedes && syscallnum == intercept_syscall)
+	{
+		//printf("Checking for err, %d, %d, %d\n", d, size, syscallnum);
+		if(size == SIZE_ALWAYS_ERROR)
+		{
+			// Looks good for an error!
+			TRACE2("Returning error %d for syscall %d\n", intercept_errno, syscallnum);
+			return true;
+		}
+		// where are we in the file?
+		if(intercept_filepos >= intercept_errorafter || intercept_filepos >= ((off_t)intercept_errorafter - size))
+		{
+			if (intercept_errno != 0)
+			{
+				TRACE3("Returning error %d for syscall %d, "
+					"file pos %d\n", intercept_errno, 
+					syscallnum, (int)intercept_filepos);
+			}
+			else if (intercept_delay_ms != 0)
+			{
+				TRACE3("Delaying %d ms for syscall %d, "
+					"file pos %d\n", intercept_delay_ms, 
+					syscallnum, (int)intercept_filepos);
+			}
+
+			return true;
+		}
+	}
+	return false;	// no error please!
+}
+
+int intercept_reterr()
+{
+	int err = intercept_errno;
+	intercept_clear_setup();
+	return err;
+}
+
+#define CHECK_FOR_FAKE_ERROR_COND(D, S, CALL, FAILRES)	\
+	if(intercept_enabled)					\
+	{										\
+		if(intercept_errornow(D, S, CALL))	\
+		{									\
+			if(intercept_delay_ms > 0) \
+			{ \
+				struct timespec tm; \
+				tm.tv_sec = intercept_delay_ms / 1000; \
+				tm.tv_nsec = (intercept_delay_ms % 1000) \
+					* 1000000; \
+				while (nanosleep(&tm, &tm) != 0 && \
+					errno == EINTR) { } \
+				intercept_clear_setup(); \
+			} \
+			else \
+			{ \
+				errno = intercept_reterr();		\
+				return FAILRES;					\
+			} \
+		}									\
+	}
+
+extern "C" int
+open(const char *path, int flags, mode_t mode)
+{
+	if(intercept_enabled)
+	{
+		if(intercept_syscall == SYS_open && strcmp(path, intercept_filename) == 0)
+		{
+			errno = intercept_reterr();
+			return -1;
+		}
+	}
+#ifdef PLATFORM_NO_SYSCALL
+	int r = TEST_open(path, flags, mode);
+#else
+	int r = syscall(SYS_open, path, flags, mode);
+#endif
+	if(intercept_enabled && intercept_filedes == -1)
+	{
+		// Right file?
+		if(strcmp(intercept_filename, path) == 0)
+		{
+			intercept_filedes = r;
+			//printf("Found file to intercept, h = %d\n", r);
+		}
+	}
+	return r;
+}
+
+extern "C" int
+open64(const char *path, int flags, mode_t mode)
+{
+	// With _FILE_OFFSET_BITS set to 64 this should really use (flags |
+	// O_LARGEFILE) here, but not actually necessary for the tests and not
+	// worth the trouble finding O_LARGEFILE
+	return open(path, flags, mode);
+}
+
+extern "C" int
+close(int d)
+{
+	CHECK_FOR_FAKE_ERROR_COND(d, SIZE_ALWAYS_ERROR, SYS_close, -1);
+#ifdef PLATFORM_NO_SYSCALL
+	int r = TEST_close(d);
+#else
+	int r = syscall(SYS_close, d);
+#endif
+	if(r == 0)
+	{
+		if(d == intercept_filedes)
+		{
+			intercept_filedes = -1;
+		}
+	}
+	return r;
+}
+
+extern "C" ssize_t
+write(int d, const void *buf, size_t nbytes)
+{
+	CHECK_FOR_FAKE_ERROR_COND(d, nbytes, SYS_write, -1);
+#ifdef PLATFORM_NO_SYSCALL
+	int r = TEST_write(d, buf, nbytes);
+#else
+	int r = syscall(SYS_write, d, buf, nbytes);
+#endif
+	if(r != -1)
+	{
+		intercept_filepos += r;
+	}
+	return r;
+}
+
+extern "C" ssize_t
+read(int d, void *buf, size_t nbytes)
+{
+	CHECK_FOR_FAKE_ERROR_COND(d, nbytes, SYS_read, -1);
+#ifdef PLATFORM_NO_SYSCALL
+	int r = TEST_read(d, buf, nbytes);
+#else
+	int r = syscall(SYS_read, d, buf, nbytes);
+#endif
+	if(r != -1)
+	{
+		intercept_filepos += r;
+	}
+	return r;
+}
+
+extern "C" ssize_t
+readv(int d, const struct iovec *iov, int iovcnt)
+{
+	// how many bytes?
+	int nbytes = 0;
+	for(int b = 0; b < iovcnt; ++b)
+	{
+		nbytes += iov[b].iov_len;
+	}
+
+	CHECK_FOR_FAKE_ERROR_COND(d, nbytes, SYS_readv, -1);
+#ifdef PLATFORM_NO_SYSCALL
+	int r = TEST_readv(d, iov, iovcnt);
+#else
+	int r = syscall(SYS_readv, d, iov, iovcnt);
+#endif
+	if(r != -1)
+	{
+		intercept_filepos += r;
+	}
+	return r;
+}
+
+extern "C" off_t
+lseek(int fildes, off_t offset, int whence)
+{
+	// random magic for lseek syscall, see /usr/src/lib/libc/sys/lseek.c
+	CHECK_FOR_FAKE_ERROR_COND(fildes, 0, SYS_lseek, -1);
+#ifdef PLATFORM_NO_SYSCALL
+	int r = TEST_lseek(fildes, offset, whence);
+#else
+	#ifdef HAVE_LSEEK_DUMMY_PARAM
+		off_t r = syscall(SYS_lseek, fildes, 0 /* extra 0 required here! */, offset, whence);
+	#elif defined(_FILE_OFFSET_BITS)
+		// Don't bother trying to call SYS__llseek on 32 bit since it is
+		// fiddly and not needed for the tests
+		off_t r = syscall(SYS_lseek, fildes, (uint32_t)offset, whence);
+	#else
+		off_t r = syscall(SYS_lseek, fildes, offset, whence);
+	#endif
+#endif
+	if(r != -1)
+	{
+		intercept_filepos = r;
+	}
+	return r;
+}
+
+#endif // n PLATFORM_CLIB_FNS_INTERCEPTION_IMPOSSIBLE