Messages in this thread Patch in this message |  | | From | Ammar Faizi <> | Subject | [RFC PATCH v1 4/6] tools/nolibc/sys: Implement `mmap()` and `munmap()` | Date | Sun, 20 Mar 2022 16:37:48 +0700 |
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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 <ammarfaizi2@gnuweeb.org> --- 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
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