From: Jérémie Galarneau <jeremie.galarneau@efficios.com>
Date: Tue, 17 Jan 2023 21:57:35 +0000 (-0500)
Subject: compat: off64_t is not defined by musl
X-Git-Url: https://git.lttng.org/?p=lttng-tools.git;a=commitdiff_plain;h=57fd993799a2b081c826f6fc8def32d28d526bfb

compat: off64_t is not defined by musl

This helps compile with latest musl, where off64_t is not defined unless
_LARGEFILE64_SOURCE is defined. On glibc, _LARGEFILE64_SOURCE is defined
if _GNU_SOURCE is defined, so the problem is only seen with musl.

Since the project uses AC_SYS_LARGEFILE, which from the autoconf doc:
"arrange for 64-bit file offsets, known as large-file support."

As such, it is safe to assume off_t is 64-bit wide. This is checked by a
static_assert to catch any platform where autoconf would let a 32-bit
off_t slip.

Reported-by: Khem Raj <raj.khem@gmail.com>
Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>
Change-Id: If2c6007a8c85bc3f3065002af8a7538b882fb4a8
---

diff --git a/src/common/compat/compat-fcntl.cpp b/src/common/compat/compat-fcntl.cpp
index f259d4577..18b6fa382 100644
--- a/src/common/compat/compat-fcntl.cpp
+++ b/src/common/compat/compat-fcntl.cpp
@@ -13,7 +13,7 @@
 
 #ifdef __linux__
 
-int compat_sync_file_range(int fd, off64_t offset, off64_t nbytes, unsigned int flags)
+int compat_sync_file_range(int fd, off_t offset, off_t nbytes, unsigned int flags)
 {
 #ifdef HAVE_SYNC_FILE_RANGE
 	return sync_file_range(fd, offset, nbytes, flags);
diff --git a/src/common/compat/fcntl.hpp b/src/common/compat/fcntl.hpp
index a526ca55d..08fe02cf4 100644
--- a/src/common/compat/fcntl.hpp
+++ b/src/common/compat/fcntl.hpp
@@ -13,16 +13,15 @@
 
 #include <common/compat/errno.hpp>
 
-#if (defined(__CYGWIN__))
-typedef long long off64_t;
-#endif
+static_assert(sizeof(off_t) == sizeof(int64_t),
+	      "Build system is misconfigured, off_t must be 64-bit wide");
 
 #if (defined(__FreeBSD__) || defined(__sun__))
 typedef off64_t loff_t;
 #endif
 
 #ifdef __linux__
-extern int compat_sync_file_range(int fd, off64_t offset, off64_t nbytes,
+extern int compat_sync_file_range(int fd, off_t offset, off_t nbytes,
 		unsigned int flags);
 #define lttng_sync_file_range(fd, offset, nbytes, flags) \
 	compat_sync_file_range(fd, offset, nbytes, flags)
@@ -39,8 +38,8 @@ extern int compat_sync_file_range(int fd, off64_t offset, off64_t nbytes,
 
 static inline int lttng_sync_file_range(
 		int fd __attribute__((unused)),
-		off64_t offset __attribute__((unused)),
-		off64_t nbytes __attribute__((unused)),
+		off_t offset __attribute__((unused)),
+		off_t nbytes __attribute__((unused)),
 		unsigned int flags __attribute__((unused)))
 {
 	return -ENOSYS;