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From: Ammar Faizi <[email protected]>
To: Willy Tarreau <[email protected]>
Cc: "Paul E. McKenney" <[email protected]>,
	Alviro Iskandar Setiawan <[email protected]>,
	Nugraha <[email protected]>,
	Linux Kernel Mailing List <[email protected]>,
	GNU/Weeb Mailing List <[email protected]>,
	Ammar Faizi <[email protected]>
Subject: [RFC PATCH v1 4/6] tools/nolibc/sys: Implement `mmap()` and `munmap()`
Date: Sun, 20 Mar 2022 16:37:48 +0700	[thread overview]
Message-ID: <[email protected]> (raw)
In-Reply-To: <[email protected]>

Implement mmap() and munmap(). Currently, they are only available for
architecures that have my_syscall6 macro. For architectures that don't
have, this function will return -1 with errno set to -ENOSYS (Function
not implemented).

This has been tested on x86 and i386.

Notes for i386:
 1) The common mmap() syscall implementation uses __NR_mmap2 instead
    of __NR_mmap.
 2) The offset must be shifted-right by 12-bit.

Signed-off-by: Ammar Faizi <[email protected]>
---
 tools/include/nolibc/sys.h | 62 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 62 insertions(+)

diff --git a/tools/include/nolibc/sys.h b/tools/include/nolibc/sys.h
index 28437863c63f..76510b19b7cf 100644
--- a/tools/include/nolibc/sys.h
+++ b/tools/include/nolibc/sys.h
@@ -14,6 +14,7 @@
 #include <asm/unistd.h>
 #include <asm/signal.h>  // for SIGCHLD
 #include <asm/ioctls.h>
+#include <asm/mman.h>
 #include <linux/fs.h>
 #include <linux/loop.h>
 #include <linux/time.h>
@@ -658,6 +659,67 @@ int mknod(const char *path, mode_t mode, dev_t dev)
 	return ret;
 }
 
+#ifndef MAP_SHARED
+#define MAP_SHARED		0x01	/* Share changes */
+#define MAP_PRIVATE		0x02	/* Changes are private */
+#define MAP_SHARED_VALIDATE	0x03	/* share + validate extension flags */
+#endif
+
+#ifndef MAP_FAILED
+#define MAP_FAILED ((void *)-1)
+#endif
+
+static __attribute__((unused))
+void *sys_mmap(void *addr, size_t length, int prot, int flags, int fd,
+	       off_t offset)
+{
+#ifndef my_syscall6
+	/* Function not implemented. */
+	return -ENOSYS;
+#else
+
+	int n;
+
+#if defined(__i386__)
+	n = __NR_mmap2;
+	offset >>= 12;
+#else
+	n = __NR_mmap;
+#endif
+
+	return (void *)my_syscall6(n, addr, length, prot, flags, fd, offset);
+#endif
+}
+
+static __attribute__((unused))
+void *mmap(void *addr, size_t length, int prot, int flags, int fd, off_t offset)
+{
+	void *ret = sys_mmap(addr, length, prot, flags, fd, offset);
+
+	if ((unsigned long)ret >= -4095UL) {
+		SET_ERRNO(-(long)ret);
+		ret = MAP_FAILED;
+	}
+	return ret;
+}
+
+static __attribute__((unused))
+int sys_munmap(void *addr, size_t length)
+{
+	return my_syscall2(__NR_munmap, addr, length);
+}
+
+static __attribute__((unused))
+int munmap(void *addr, size_t length)
+{
+	int ret = sys_munmap(addr, length);
+
+	if (ret < 0) {
+		SET_ERRNO(-ret);
+		ret = -1;
+	}
+	return ret;
+}
 
 /*
  * int mount(const char *source, const char *target,
-- 
Ammar Faizi


  parent reply	other threads:[~2022-03-20  9:38 UTC|newest]

Thread overview: 29+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-03-20  9:37 [RFC PATCH v1 0/6] Add dynamic memory allocator support for nolibc Ammar Faizi
2022-03-20  9:37 ` [RFC PATCH v1 1/6] tools/nolibc: x86-64: Update System V ABI document link Ammar Faizi
2022-03-20  9:37 ` [RFC PATCH v1 2/6] tools/nolibc: Make the entry point not weak for clang Ammar Faizi
2022-03-20 19:16   ` Willy Tarreau
2022-03-21 11:38     ` Ammar Faizi
2022-03-21 17:27       ` Nick Desaulniers
2022-03-20  9:37 ` [RFC PATCH v1 3/6] tools/nolibc: i386: Implement syscall with 6 arguments Ammar Faizi
2022-03-20 10:33   ` Alviro Iskandar Setiawan
2022-03-20 10:42     ` Alviro Iskandar Setiawan
2022-03-20 15:09       ` Ammar Faizi
2022-03-20 13:10   ` David Laight
2022-03-20 14:01     ` Willy Tarreau
2022-03-20 15:04     ` Ammar Faizi
2022-03-20 18:22       ` David Laight
2022-03-20  9:37 ` Ammar Faizi [this message]
2022-03-20  9:37 ` [RFC PATCH v1 5/6] tools/nolibc/stdlib: Implement `malloc()`, `calloc()`, `realloc()` and `free()` Ammar Faizi
2022-03-20 15:50   ` Alviro Iskandar Setiawan
2022-03-20 16:10     ` Ammar Faizi
2022-03-20 16:16   ` Willy Tarreau
2022-03-20 16:36     ` Ammar Faizi
2022-03-20 16:46       ` Willy Tarreau
2022-03-20  9:37 ` [RFC PATCH v1 6/6] tools/include/string: Implement `strdup()` and `strndup()` Ammar Faizi
2022-03-20 15:55   ` Alviro Iskandar Setiawan
2022-03-20 16:10     ` Ammar Faizi
2022-03-21  7:53   ` Willy Tarreau
2022-03-21  8:16     ` Alviro Iskandar Setiawan
2022-03-21  8:51       ` Willy Tarreau
2022-03-21 11:36     ` Ammar Faizi
2022-03-21 11:43       ` Willy Tarreau

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