From 0f34a362c8644f212138fb8de8e0fba54941e757 Mon Sep 17 00:00:00 2001 From: Julien Olivain Date: Sun, 14 Jul 2024 16:28:08 +0200 Subject: [PATCH] btrfs-progs: add uClibc-ng compatibility for printf format %pV Commit [1] 164bc10d "btrfs-progs: add musl compatibility for printf format %pV" added a logic to detect the presence of the glibc header, and if present, to use the register_printf_specifier() and register_printf_modifier() functions. The original intent (as the commit log suggests), was to support the musl libc, which does not provides this header. When compiling with another libc, such as uClibc-ng, btrfs-progs fail to build with error: common/messages.c: In function 'print_va_format': common/messages.c:51:19: error: 'const struct printf_info' has no member named 'user' 51 | if (!(info->user & va_modifier)) | ^~ common/messages.c: In function 'btrfs_no_printk': common/messages.c:76:17: warning: implicit declaration of function 'register_printf_specifier'; did you mean 'register_printf_function'? [-Wimplicit-function-declaration] 76 | register_printf_specifier('V', print_va_format, | ^~~~~~~~~~~~~~~~~~~~~~~~~ | register_printf_function common/messages.c:78:31: warning: implicit declaration of function 'register_printf_modifier'; did you mean 'register_printf_function'? [-Wimplicit-function-declaration] 78 | va_modifier = register_printf_modifier(L"p"); | ^~~~~~~~~~~~~~~~~~~~~~~~ | register_printf_function This is because uClibc-ng provides a header, but not the register_printf_specifier() and register_printf_modifier() functions. See [2]. It mainly includes register_printf_function(). uClibc-ng emulates an older glibc behavior. Glibc added support for printf user elements in commit [3] (first included in glibc-2.10, in 2009). Checking only the is not sufficient. This commit fixes this build issue by refining the detection logic of the functions required by btrfs-progs. [1] https://github.com/kdave/btrfs-progs/commit/164bc10dfc08d8754d23ef0d6d7281e139d6cd53 [2] https://gogs.waldemar-brodkorb.de/oss/uclibc-ng/src/v1.0.49/include/printf.h [3] https://sourceware.org/git/?p=glibc.git;a=commitdiff;h=9d26efa90c6dcbcd6b3e586c9927b6058ef4d529 Upstream: Proposed: https://github.com/kdave/btrfs-progs/pull/843 Signed-off-by: Julien Olivain --- common/messages.h | 4 +++- configure.ac | 4 ++++ 2 files changed, 7 insertions(+), 1 deletion(-) diff --git a/common/messages.h b/common/messages.h index d6d4044d..aced7c9b 100644 --- a/common/messages.h +++ b/common/messages.h @@ -25,7 +25,9 @@ /* * Workaround for custom format %pV that may not be supported on all libcs. */ -#ifdef HAVE_PRINTF_H +#if defined(HAVE_PRINTF_H) \ + && defined(HAVE_REGISTER_PRINTF_SPECIFIER) \ + && defined(HAVE_REGISTER_PRINTF_MODIFIER) #define DECLARE_PV(name) struct va_format name #define PV_FMT "%pV" #define PV_VAL(va) &va diff --git a/configure.ac b/configure.ac index b69973b3..62b88973 100644 --- a/configure.ac +++ b/configure.ac @@ -95,6 +95,10 @@ AC_CHECK_HEADERS([linux/hw_breakpoint.h]) AC_CHECK_HEADERS([linux/fsverity.h]) AC_CHECK_HEADERS([printf.h]) +dnl Check for printf.h functions. +AC_CHECK_FUNCS([register_printf_specifier]) +AC_CHECK_FUNCS([register_printf_modifier]) + if grep -q 'HAVE_LINUX_FSVERITY_H.*1' confdefs.h; then have_fsverity='yes' else -- 2.45.2