diff options
author | Chris Wilson <chris+github@qwirx.com> | 2006-11-26 19:43:20 +0000 |
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committer | Chris Wilson <chris+github@qwirx.com> | 2006-11-26 19:43:20 +0000 |
commit | aa1e32e97f007a547e57cd6be5ecf190b4ff7cfd (patch) | |
tree | a021c6b135463207a4bac94ffe61f057b466a820 /lib | |
parent | c83d51cd16dd979273a960f8ac9375e10fa93942 (diff) |
Moved intercept code to a library module to allow it to be used by
test/bbackupd as well (refs #3)
Diffstat (limited to 'lib')
-rw-r--r-- | lib/intercept/intercept.cpp | 315 |
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 |