From: Dan Gohman <dev@sunfishcode.online>
Date: Mon, 11 Jul 2022 15:27:39 +0000 (-0700)
Subject: Add a `getpagesize` function. (#300)
X-Git-Url: https://git.proxmox.com/?p=wasi-libc.git;a=commitdiff_plain;h=e066a8b9d9c15e4c67fbcaeed3b62470f8785ce0

Add a `getpagesize` function. (#300)

* Add a `getpagesize` function.

This adds a `getpagesize` function. This interface is deprecated in POSIX,
but it's sufficiently widely used and not problematic in practice.

* Use musl's `getpagesize`.

* Enable the `getpagesize` declaration in unistd.h.
---

diff --git a/Makefile b/Makefile
index 4341980..6eaf094 100644
--- a/Makefile
+++ b/Makefile
@@ -145,6 +145,7 @@ LIBC_TOP_HALF_MUSL_SOURCES = \
         env/unsetenv.c \
         unistd/posix_close.c \
         stat/futimesat.c \
+        legacy/getpagesize.c \
     ) \
     $(filter-out %/procfdname.c %/syscall.c %/syscall_ret.c %/vdso.c %/version.c, \
                  $(wildcard $(LIBC_TOP_HALF_MUSL_SRC_DIR)/internal/*.c)) \
diff --git a/expected/wasm32-wasi/defined-symbols.txt b/expected/wasm32-wasi/defined-symbols.txt
index 69242c7..40023d9 100644
--- a/expected/wasm32-wasi/defined-symbols.txt
+++ b/expected/wasm32-wasi/defined-symbols.txt
@@ -681,6 +681,7 @@ getline
 getopt
 getopt_long
 getopt_long_only
+getpagesize
 getpid
 getrusage
 getsockopt
diff --git a/libc-bottom-half/headers/public/__macro_PAGESIZE.h b/libc-bottom-half/headers/public/__macro_PAGESIZE.h
index 0243c98..d892220 100644
--- a/libc-bottom-half/headers/public/__macro_PAGESIZE.h
+++ b/libc-bottom-half/headers/public/__macro_PAGESIZE.h
@@ -5,6 +5,11 @@
  * The page size in WebAssembly is fixed at 64 KiB. If this ever changes,
  * it's expected that applications will need to opt in, so we can change
  * this.
+ *
+ * If this ever needs to be a value outside the range of an `int`, the
+ * `getpagesize` function which returns this value will need special
+ * consideration. POSIX has deprecated `getpagesize` in favor of
+ * `sysconf(_SC_PAGESIZE)` which does not have this problem.
  */
 #define PAGESIZE (0x10000)
 
diff --git a/libc-top-half/musl/include/unistd.h b/libc-top-half/musl/include/unistd.h
index 9231d60..b5cb5c6 100644
--- a/libc-top-half/musl/include/unistd.h
+++ b/libc-top-half/musl/include/unistd.h
@@ -244,7 +244,9 @@ void *sbrk(intptr_t);
 pid_t vfork(void);
 int vhangup(void);
 int chroot(const char *);
+#endif
 int getpagesize(void);
+#ifdef __wasilibc_unmodified_upstream /* WASI has no processes */
 int getdtablesize(void);
 int sethostname(const char *, size_t);
 int getdomainname(char *, size_t);