qemu-e2k/include/qemu/log.h
Robert Foley 7606488c0e Add use of RCU for qemu_logfile.
This now allows changing the logfile while logging is active,
and also solves the issue of a seg fault while changing the logfile.

Any read access to the qemu_logfile handle will use
the rcu_read_lock()/unlock() around the use of the handle.
To fetch the handle we will use atomic_rcu_read().
We also in many cases do a check for validity of the
logfile handle before using it to deal with the case where the
file is closed and set to NULL.

The cases where we write to the qemu_logfile will use atomic_rcu_set().
Writers will also use call_rcu() with a newly added qemu_logfile_free
function for freeing/closing when readers have finished.

Signed-off-by: Robert Foley <robert.foley@linaro.org>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20191118211528.3221-6-robert.foley@linaro.org>
2019-12-18 20:18:02 +00:00

166 lines
4.3 KiB
C

#ifndef QEMU_LOG_H
#define QEMU_LOG_H
/* A small part of this API is split into its own header */
#include "qemu/log-for-trace.h"
#include "qemu/rcu.h"
typedef struct QemuLogFile {
struct rcu_head rcu;
FILE *fd;
} QemuLogFile;
/* Private global variable, don't use */
extern QemuLogFile *qemu_logfile;
/*
* The new API:
*
*/
/* Log settings checking macros: */
/* Returns true if qemu_log() will really write somewhere
*/
static inline bool qemu_log_enabled(void)
{
return qemu_logfile != NULL;
}
/* Returns true if qemu_log() will write somewhere else than stderr
*/
static inline bool qemu_log_separate(void)
{
QemuLogFile *logfile;
bool res = false;
rcu_read_lock();
logfile = atomic_rcu_read(&qemu_logfile);
if (logfile && logfile->fd != stderr) {
res = true;
}
rcu_read_unlock();
return res;
}
#define CPU_LOG_TB_OUT_ASM (1 << 0)
#define CPU_LOG_TB_IN_ASM (1 << 1)
#define CPU_LOG_TB_OP (1 << 2)
#define CPU_LOG_TB_OP_OPT (1 << 3)
#define CPU_LOG_INT (1 << 4)
#define CPU_LOG_EXEC (1 << 5)
#define CPU_LOG_PCALL (1 << 6)
#define CPU_LOG_TB_CPU (1 << 8)
#define CPU_LOG_RESET (1 << 9)
#define LOG_UNIMP (1 << 10)
#define LOG_GUEST_ERROR (1 << 11)
#define CPU_LOG_MMU (1 << 12)
#define CPU_LOG_TB_NOCHAIN (1 << 13)
#define CPU_LOG_PAGE (1 << 14)
/* LOG_TRACE (1 << 15) is defined in log-for-trace.h */
#define CPU_LOG_TB_OP_IND (1 << 16)
#define CPU_LOG_TB_FPU (1 << 17)
#define CPU_LOG_PLUGIN (1 << 18)
/* Lock output for a series of related logs. Since this is not needed
* for a single qemu_log / qemu_log_mask / qemu_log_mask_and_addr, we
* assume that qemu_loglevel_mask has already been tested, and that
* qemu_loglevel is never set when qemu_logfile is unset.
*/
static inline FILE *qemu_log_lock(void)
{
QemuLogFile *logfile;
rcu_read_lock();
logfile = atomic_rcu_read(&qemu_logfile);
if (logfile) {
qemu_flockfile(logfile->fd);
return logfile->fd;
} else {
return NULL;
}
}
static inline void qemu_log_unlock(FILE *fd)
{
if (fd) {
qemu_funlockfile(fd);
}
rcu_read_unlock();
}
/* Logging functions: */
/* vfprintf-like logging function
*/
static inline void GCC_FMT_ATTR(1, 0)
qemu_log_vprintf(const char *fmt, va_list va)
{
QemuLogFile *logfile;
rcu_read_lock();
logfile = atomic_rcu_read(&qemu_logfile);
if (logfile) {
vfprintf(logfile->fd, fmt, va);
}
rcu_read_unlock();
}
/* log only if a bit is set on the current loglevel mask:
* @mask: bit to check in the mask
* @fmt: printf-style format string
* @args: optional arguments for format string
*/
#define qemu_log_mask(MASK, FMT, ...) \
do { \
if (unlikely(qemu_loglevel_mask(MASK))) { \
qemu_log(FMT, ## __VA_ARGS__); \
} \
} while (0)
/* log only if a bit is set on the current loglevel mask
* and we are in the address range we care about:
* @mask: bit to check in the mask
* @addr: address to check in dfilter
* @fmt: printf-style format string
* @args: optional arguments for format string
*/
#define qemu_log_mask_and_addr(MASK, ADDR, FMT, ...) \
do { \
if (unlikely(qemu_loglevel_mask(MASK)) && \
qemu_log_in_addr_range(ADDR)) { \
qemu_log(FMT, ## __VA_ARGS__); \
} \
} while (0)
/* Maintenance: */
/* define log items */
typedef struct QEMULogItem {
int mask;
const char *name;
const char *help;
} QEMULogItem;
extern const QEMULogItem qemu_log_items[];
void qemu_set_log(int log_flags);
void qemu_log_needs_buffers(void);
void qemu_set_log_filename(const char *filename, Error **errp);
void qemu_set_dfilter_ranges(const char *ranges, Error **errp);
bool qemu_log_in_addr_range(uint64_t addr);
int qemu_str_to_log_mask(const char *str);
/* Print a usage message listing all the valid logging categories
* to the specified FILE*.
*/
void qemu_print_log_usage(FILE *f);
/* fflush() the log file */
void qemu_log_flush(void);
/* Close the log file */
void qemu_log_close(void);
#endif