The linux-user and bsd-user trees both widely use a function called `gemu_log` (notice the 'g') for miscellaneous and strace logging. This function predates the newer `qemu_log` function, and has a few drawbacks compared to `qemu_log`:
1. Always logs to `stderr`, no logging redirection. 2. "Miscellaneous" logging cannot be disabled, so it may mix with guest logging. 3. Inconsistency with other parts of the QEMU codebase, and a confusing name. The second issue is especially troubling because it can interfere with programs that expect to communicate via stderr. This change introduces two new logging masks to the `qemu_log` subsystem to support its use for user-mode logging. The `LOG_USER` mask, for miscellaneous logs, and the `LOG_STRACE` mask for strace-specific logging. Further, it replaces all existing uses of `gemu_log` with the appropriate `qemu_log_mask(LOG_{USER,STRACE}, ...)` based on the log message. To avoid potential backwards incompatibility, this patch series also introduces a new flag: `-no-force-user-mode-logging`. Since "user mode" logging was always enabled before this change, by-default the LOG_USER mask is always set. The flag is provided for users that want to disable LOG_USER. Hopefully, this flag can be removed, or turned into a no-op in the futre, and -d/QEMU_LOG can be used directly to enable user-mode logging if desired. Unfortunately, this change introduces one small backwards incompatibility for the linux-user tree: If an explicit `-D` option is provided, or the `QEMU_LOG_FILENAME`_ environment variable is set, strace and user-mode logging statements will log to the QEMU log file instead of stderr. Tested: * Built with clang 9 and g++ 8.3 * `make check` run with clang 9 build * Verified: * QEMU_STRACE/-strace still works for linux-user * -no-force-user-mode-logging uses QEMU_LOG + `user_mode` or `strace` can be set in QEMU_LOG to trigger the appropriate logging. Not tested: * Build/logging with bsd-user. I do not have easy access to a BSD system. Josh Kunz (4): linux-user: Use `qemu_log' for non-strace logging linux-user: Use `qemu_log' for strace linux-user: remove gemu_log from the linux-user tree bsd-user: Replace gemu_log with qemu_log bsd-user/main.c | 13 +- bsd-user/qemu.h | 2 - bsd-user/strace.c | 32 ++- bsd-user/syscall.c | 31 ++- include/qemu/log.h | 15 ++ linux-user/arm/cpu_loop.c | 5 +- linux-user/fd-trans.c | 55 +++-- linux-user/main.c | 50 +++- linux-user/qemu.h | 2 - linux-user/signal.c | 3 +- linux-user/strace.c | 479 +++++++++++++++++++------------------- linux-user/syscall.c | 43 ++-- linux-user/vm86.c | 3 +- util/log.c | 5 + 14 files changed, 404 insertions(+), 334 deletions(-) -- 2.25.0.rc1.283.g88dfdc4193-goog