Use __syscall() helper to shrink 252 lines of code.
$ git show HEAD^:tools/include/nolibc/sys.h | wc -l
1425
$ git show HEAD:tools/include/nolibc/sys.h | wc -l
1173
$ echo "1425-1173" | bc -l
252
Signed-off-by: Zhangjin Wu <[email protected]>
---
tools/include/nolibc/sys.h | 336 +++++--------------------------------
1 file changed, 42 insertions(+), 294 deletions(-)
diff --git a/tools/include/nolibc/sys.h b/tools/include/nolibc/sys.h
index f6e3168b3e50..0cfc5157845a 100644
--- a/tools/include/nolibc/sys.h
+++ b/tools/include/nolibc/sys.h
@@ -108,13 +108,7 @@ int sys_chdir(const char *path)
static __attribute__((unused))
int chdir(const char *path)
{
- int ret = sys_chdir(path);
-
- if (ret < 0) {
- SET_ERRNO(-ret);
- ret = -1;
- }
- return ret;
+ return __syscall(chdir, path);
}
@@ -137,13 +131,7 @@ int sys_chmod(const char *path, mode_t mode)
static __attribute__((unused))
int chmod(const char *path, mode_t mode)
{
- int ret = sys_chmod(path, mode);
-
- if (ret < 0) {
- SET_ERRNO(-ret);
- ret = -1;
- }
- return ret;
+ return __syscall(chmod, path, mode);
}
@@ -166,13 +154,7 @@ int sys_chown(const char *path, uid_t owner, gid_t group)
static __attribute__((unused))
int chown(const char *path, uid_t owner, gid_t group)
{
- int ret = sys_chown(path, owner, group);
-
- if (ret < 0) {
- SET_ERRNO(-ret);
- ret = -1;
- }
- return ret;
+ return __syscall(chown, path, owner, group);
}
@@ -189,13 +171,7 @@ int sys_chroot(const char *path)
static __attribute__((unused))
int chroot(const char *path)
{
- int ret = sys_chroot(path);
-
- if (ret < 0) {
- SET_ERRNO(-ret);
- ret = -1;
- }
- return ret;
+ return __syscall(chroot, path);
}
@@ -212,13 +188,7 @@ int sys_close(int fd)
static __attribute__((unused))
int close(int fd)
{
- int ret = sys_close(fd);
-
- if (ret < 0) {
- SET_ERRNO(-ret);
- ret = -1;
- }
- return ret;
+ return __syscall(close, fd);
}
@@ -235,13 +205,7 @@ int sys_dup(int fd)
static __attribute__((unused))
int dup(int fd)
{
- int ret = sys_dup(fd);
-
- if (ret < 0) {
- SET_ERRNO(-ret);
- ret = -1;
- }
- return ret;
+ return __syscall(dup, fd);
}
@@ -264,13 +228,7 @@ int sys_dup2(int old, int new)
static __attribute__((unused))
int dup2(int old, int new)
{
- int ret = sys_dup2(old, new);
-
- if (ret < 0) {
- SET_ERRNO(-ret);
- ret = -1;
- }
- return ret;
+ return __syscall(dup2, old, new);
}
@@ -288,13 +246,7 @@ int sys_dup3(int old, int new, int flags)
static __attribute__((unused))
int dup3(int old, int new, int flags)
{
- int ret = sys_dup3(old, new, flags);
-
- if (ret < 0) {
- SET_ERRNO(-ret);
- ret = -1;
- }
- return ret;
+ return __syscall(dup3, old, new, flags);
}
#endif
@@ -312,13 +264,7 @@ int sys_execve(const char *filename, char *const argv[], char *const envp[])
static __attribute__((unused))
int execve(const char *filename, char *const argv[], char *const envp[])
{
- int ret = sys_execve(filename, argv, envp);
-
- if (ret < 0) {
- SET_ERRNO(-ret);
- ret = -1;
- }
- return ret;
+ return __syscall(execve, filename, argv, envp);
}
@@ -365,13 +311,7 @@ pid_t sys_fork(void)
static __attribute__((unused))
pid_t fork(void)
{
- pid_t ret = sys_fork();
-
- if (ret < 0) {
- SET_ERRNO(-ret);
- ret = -1;
- }
- return ret;
+ return __syscall(fork);
}
@@ -388,13 +328,7 @@ int sys_fsync(int fd)
static __attribute__((unused))
int fsync(int fd)
{
- int ret = sys_fsync(fd);
-
- if (ret < 0) {
- SET_ERRNO(-ret);
- ret = -1;
- }
- return ret;
+ return __syscall(fsync, fd);
}
@@ -411,13 +345,7 @@ int sys_getdents64(int fd, struct linux_dirent64 *dirp, int count)
static __attribute__((unused))
int getdents64(int fd, struct linux_dirent64 *dirp, int count)
{
- int ret = sys_getdents64(fd, dirp, count);
-
- if (ret < 0) {
- SET_ERRNO(-ret);
- ret = -1;
- }
- return ret;
+ return __syscall(getdents64, fd, dirp, count);
}
@@ -455,13 +383,7 @@ pid_t sys_getpgid(pid_t pid)
static __attribute__((unused))
pid_t getpgid(pid_t pid)
{
- pid_t ret = sys_getpgid(pid);
-
- if (ret < 0) {
- SET_ERRNO(-ret);
- ret = -1;
- }
- return ret;
+ return __syscall(getpgid, pid);
}
@@ -562,13 +484,7 @@ int sys_gettimeofday(struct timeval *tv, struct timezone *tz)
static __attribute__((unused))
int gettimeofday(struct timeval *tv, struct timezone *tz)
{
- int ret = sys_gettimeofday(tv, tz);
-
- if (ret < 0) {
- SET_ERRNO(-ret);
- ret = -1;
- }
- return ret;
+ return __syscall(gettimeofday, tv, tz);
}
@@ -606,13 +522,7 @@ int sys_ioctl(int fd, unsigned long req, void *value)
static __attribute__((unused))
int ioctl(int fd, unsigned long req, void *value)
{
- int ret = sys_ioctl(fd, req, value);
-
- if (ret < 0) {
- SET_ERRNO(-ret);
- ret = -1;
- }
- return ret;
+ return __syscall(ioctl, fd, req, value);
}
/*
@@ -628,13 +538,7 @@ int sys_kill(pid_t pid, int signal)
static __attribute__((unused))
int kill(pid_t pid, int signal)
{
- int ret = sys_kill(pid, signal);
-
- if (ret < 0) {
- SET_ERRNO(-ret);
- ret = -1;
- }
- return ret;
+ return __syscall(kill, pid, signal);
}
@@ -657,13 +561,7 @@ int sys_link(const char *old, const char *new)
static __attribute__((unused))
int link(const char *old, const char *new)
{
- int ret = sys_link(old, new);
-
- if (ret < 0) {
- SET_ERRNO(-ret);
- ret = -1;
- }
- return ret;
+ return __syscall(link, old, new);
}
@@ -684,13 +582,7 @@ off_t sys_lseek(int fd, off_t offset, int whence)
static __attribute__((unused))
off_t lseek(int fd, off_t offset, int whence)
{
- off_t ret = sys_lseek(fd, offset, whence);
-
- if (ret < 0) {
- SET_ERRNO(-ret);
- ret = -1;
- }
- return ret;
+ return __syscall(lseek, fd, offset, whence);
}
@@ -713,13 +605,7 @@ int sys_mkdir(const char *path, mode_t mode)
static __attribute__((unused))
int mkdir(const char *path, mode_t mode)
{
- int ret = sys_mkdir(path, mode);
-
- if (ret < 0) {
- SET_ERRNO(-ret);
- ret = -1;
- }
- return ret;
+ return __syscall(mkdir, path, mode);
}
@@ -742,13 +628,7 @@ long sys_mknod(const char *path, mode_t mode, dev_t dev)
static __attribute__((unused))
int mknod(const char *path, mode_t mode, dev_t dev)
{
- int ret = sys_mknod(path, mode, dev);
-
- if (ret < 0) {
- SET_ERRNO(-ret);
- ret = -1;
- }
- return ret;
+ return __syscall(mknod, path, mode, dev);
}
#ifndef MAP_SHARED
@@ -806,13 +686,7 @@ int sys_munmap(void *addr, size_t 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;
+ return __syscall(munmap, addr, length);
}
/*
@@ -832,13 +706,7 @@ int mount(const char *src, const char *tgt,
const char *fst, unsigned long flags,
const void *data)
{
- int ret = sys_mount(src, tgt, fst, flags, data);
-
- if (ret < 0) {
- SET_ERRNO(-ret);
- ret = -1;
- }
- return ret;
+ return __syscall(mount, src, tgt, fst, flags, data);
}
@@ -872,13 +740,7 @@ int open(const char *path, int flags, ...)
va_end(args);
}
- ret = sys_open(path, flags, mode);
-
- if (ret < 0) {
- SET_ERRNO(-ret);
- ret = -1;
- }
- return ret;
+ return __syscall(open, path, flags, mode);
}
@@ -898,13 +760,7 @@ static __attribute__((unused))
int prctl(int option, unsigned long arg2, unsigned long arg3,
unsigned long arg4, unsigned long arg5)
{
- int ret = sys_prctl(option, arg2, arg3, arg4, arg5);
-
- if (ret < 0) {
- SET_ERRNO(-ret);
- ret = -1;
- }
- return ret;
+ return __syscall(prctl, option, arg2, arg3, arg4, arg5);
}
@@ -921,13 +777,7 @@ int sys_pivot_root(const char *new, const char *old)
static __attribute__((unused))
int pivot_root(const char *new, const char *old)
{
- int ret = sys_pivot_root(new, old);
-
- if (ret < 0) {
- SET_ERRNO(-ret);
- ret = -1;
- }
- return ret;
+ return __syscall(pivot_root, new, old);
}
@@ -956,13 +806,7 @@ int sys_poll(struct pollfd *fds, int nfds, int timeout)
static __attribute__((unused))
int poll(struct pollfd *fds, int nfds, int timeout)
{
- int ret = sys_poll(fds, nfds, timeout);
-
- if (ret < 0) {
- SET_ERRNO(-ret);
- ret = -1;
- }
- return ret;
+ return __syscall(poll, fds, nfds, timeout);
}
@@ -979,13 +823,7 @@ ssize_t sys_read(int fd, void *buf, size_t count)
static __attribute__((unused))
ssize_t read(int fd, void *buf, size_t count)
{
- ssize_t ret = sys_read(fd, buf, count);
-
- if (ret < 0) {
- SET_ERRNO(-ret);
- ret = -1;
- }
- return ret;
+ return __syscall(read, fd, buf, count);
}
@@ -1003,13 +841,7 @@ ssize_t sys_reboot(int magic1, int magic2, int cmd, void *arg)
static __attribute__((unused))
int reboot(int cmd)
{
- int ret = sys_reboot(LINUX_REBOOT_MAGIC1, LINUX_REBOOT_MAGIC2, cmd, 0);
-
- if (ret < 0) {
- SET_ERRNO(-ret);
- ret = -1;
- }
- return ret;
+ return __syscall(reboot, LINUX_REBOOT_MAGIC1, LINUX_REBOOT_MAGIC2, cmd, 0);
}
@@ -1026,13 +858,7 @@ int sys_sched_yield(void)
static __attribute__((unused))
int sched_yield(void)
{
- int ret = sys_sched_yield();
-
- if (ret < 0) {
- SET_ERRNO(-ret);
- ret = -1;
- }
- return ret;
+ return __syscall(sched_yield);
}
@@ -1072,13 +898,7 @@ int sys_select(int nfds, fd_set *rfds, fd_set *wfds, fd_set *efds, struct timeva
static __attribute__((unused))
int select(int nfds, fd_set *rfds, fd_set *wfds, fd_set *efds, struct timeval *timeout)
{
- int ret = sys_select(nfds, rfds, wfds, efds, timeout);
-
- if (ret < 0) {
- SET_ERRNO(-ret);
- ret = -1;
- }
- return ret;
+ return __syscall(select, nfds, rfds, wfds, efds, timeout);
}
@@ -1095,13 +915,7 @@ int sys_setpgid(pid_t pid, pid_t pgid)
static __attribute__((unused))
int setpgid(pid_t pid, pid_t pgid)
{
- int ret = sys_setpgid(pid, pgid);
-
- if (ret < 0) {
- SET_ERRNO(-ret);
- ret = -1;
- }
- return ret;
+ return __syscall(setpgid, pid, pgid);
}
@@ -1118,13 +932,7 @@ pid_t sys_setsid(void)
static __attribute__((unused))
pid_t setsid(void)
{
- pid_t ret = sys_setsid();
-
- if (ret < 0) {
- SET_ERRNO(-ret);
- ret = -1;
- }
- return ret;
+ return __syscall(setsid);
}
#if defined(__NR_statx)
@@ -1141,13 +949,7 @@ int sys_statx(int fd, const char *path, int flags, unsigned int mask, struct sta
static __attribute__((unused))
int statx(int fd, const char *path, int flags, unsigned int mask, struct statx *buf)
{
- int ret = sys_statx(fd, path, flags, mask, buf);
-
- if (ret < 0) {
- SET_ERRNO(-ret);
- ret = -1;
- }
- return ret;
+ return __syscall(statx, fd, path, flags, mask, buf);
}
#endif
@@ -1227,13 +1029,7 @@ int sys_stat(const char *path, struct stat *buf)
static __attribute__((unused))
int stat(const char *path, struct stat *buf)
{
- int ret = sys_stat(path, buf);
-
- if (ret < 0) {
- SET_ERRNO(-ret);
- ret = -1;
- }
- return ret;
+ return __syscall(stat, path, buf);
}
@@ -1256,13 +1052,7 @@ int sys_symlink(const char *old, const char *new)
static __attribute__((unused))
int symlink(const char *old, const char *new)
{
- int ret = sys_symlink(old, new);
-
- if (ret < 0) {
- SET_ERRNO(-ret);
- ret = -1;
- }
- return ret;
+ return __syscall(symlink, old, new);
}
@@ -1296,13 +1086,7 @@ int sys_umount2(const char *path, int flags)
static __attribute__((unused))
int umount2(const char *path, int flags)
{
- int ret = sys_umount2(path, flags);
-
- if (ret < 0) {
- SET_ERRNO(-ret);
- ret = -1;
- }
- return ret;
+ return __syscall(umount2, path, flags);
}
@@ -1325,13 +1109,7 @@ int sys_unlink(const char *path)
static __attribute__((unused))
int unlink(const char *path)
{
- int ret = sys_unlink(path);
-
- if (ret < 0) {
- SET_ERRNO(-ret);
- ret = -1;
- }
- return ret;
+ return __syscall(unlink, path);
}
@@ -1354,38 +1132,20 @@ pid_t sys_wait4(pid_t pid, int *status, int options, struct rusage *rusage)
static __attribute__((unused))
pid_t wait(int *status)
{
- pid_t ret = sys_wait4(-1, status, 0, NULL);
-
- if (ret < 0) {
- SET_ERRNO(-ret);
- ret = -1;
- }
- return ret;
+ return __syscall(wait4, -1, status, 0, NULL);
}
static __attribute__((unused))
pid_t wait4(pid_t pid, int *status, int options, struct rusage *rusage)
{
- pid_t ret = sys_wait4(pid, status, options, rusage);
-
- if (ret < 0) {
- SET_ERRNO(-ret);
- ret = -1;
- }
- return ret;
+ return __syscall(wait4, pid, status, options, rusage);
}
static __attribute__((unused))
pid_t waitpid(pid_t pid, int *status, int options)
{
- pid_t ret = sys_wait4(pid, status, options, NULL);
-
- if (ret < 0) {
- SET_ERRNO(-ret);
- ret = -1;
- }
- return ret;
+ return __syscall(wait4, pid, status, options, NULL);
}
@@ -1402,13 +1162,7 @@ ssize_t sys_write(int fd, const void *buf, size_t count)
static __attribute__((unused))
ssize_t write(int fd, const void *buf, size_t count)
{
- ssize_t ret = sys_write(fd, buf, count);
-
- if (ret < 0) {
- SET_ERRNO(-ret);
- ret = -1;
- }
- return ret;
+ return __syscall(write, fd, buf, count);
}
@@ -1425,13 +1179,7 @@ int sys_memfd_create(const char *name, unsigned int flags)
static __attribute__((unused))
int memfd_create(const char *name, unsigned int flags)
{
- ssize_t ret = sys_memfd_create(name, flags);
-
- if (ret < 0) {
- SET_ERRNO(-ret);
- ret = -1;
- }
- return ret;
+ return __syscall(memfd_create, name, flags);
}
/* make sure to include all global symbols */
--
2.25.1
Hi Zhangjin,
On 2023-06-06 16:17:38+0800, Zhangjin Wu wrote:
> Use __syscall() helper to shrink 252 lines of code.
>
> $ git show HEAD^:tools/include/nolibc/sys.h | wc -l
> 1425
> $ git show HEAD:tools/include/nolibc/sys.h | wc -l
> 1173
> $ echo "1425-1173" | bc -l
> 252
>
> Signed-off-by: Zhangjin Wu <[email protected]>
> ---
> tools/include/nolibc/sys.h | 336 +++++--------------------------------
> 1 file changed, 42 insertions(+), 294 deletions(-)
>
> diff --git a/tools/include/nolibc/sys.h b/tools/include/nolibc/sys.h
> index f6e3168b3e50..0cfc5157845a 100644
> --- a/tools/include/nolibc/sys.h
> +++ b/tools/include/nolibc/sys.h
> @@ -108,13 +108,7 @@ int sys_chdir(const char *path)
> static __attribute__((unused))
> int chdir(const char *path)
> {
> - int ret = sys_chdir(path);
> -
> - if (ret < 0) {
> - SET_ERRNO(-ret);
> - ret = -1;
> - }
> - return ret;
> + return __syscall(chdir, path);
To be honest I'm still not a big fan of the __syscall macro.
It's a bit too magic for too little gain.
The commit message argues that the patches make the code shorter.
However doing
__sysret(sys_chdir(path));
instead of
__syscall(chdir, path);
is only three characters longer and the same amout of lines.
Otherwise we would have syscall() _syscall() and __syscall() each doing
different things.
And __syscall does not behave like a regular function.
The rest of the patchset looks great.
Maybe Willy can break the tie?
Thomas
Note: If we figure out a way to build syscall() without macros I would
like that also :-)
> Hi Zhangjin,
>
> On 2023-06-06 16:17:38+0800, Zhangjin Wu wrote:
> > Use __syscall() helper to shrink 252 lines of code.
> >
> > $ git show HEAD^:tools/include/nolibc/sys.h | wc -l
> > 1425
> > $ git show HEAD:tools/include/nolibc/sys.h | wc -l
> > 1173
> > $ echo "1425-1173" | bc -l
> > 252
> >
> > Signed-off-by: Zhangjin Wu <[email protected]>
> > ---
> > tools/include/nolibc/sys.h | 336 +++++--------------------------------
> > 1 file changed, 42 insertions(+), 294 deletions(-)
> >
> > diff --git a/tools/include/nolibc/sys.h b/tools/include/nolibc/sys.h
> > index f6e3168b3e50..0cfc5157845a 100644
> > --- a/tools/include/nolibc/sys.h
> > +++ b/tools/include/nolibc/sys.h
> > @@ -108,13 +108,7 @@ int sys_chdir(const char *path)
> > static __attribute__((unused))
> > int chdir(const char *path)
> > {
> > - int ret = sys_chdir(path);
> > -
> > - if (ret < 0) {
> > - SET_ERRNO(-ret);
> > - ret = -1;
> > - }
> > - return ret;
> > + return __syscall(chdir, path);
>
> To be honest I'm still not a big fan of the __syscall macro.
> It's a bit too magic for too little gain.
>
> The commit message argues that the patches make the code shorter.
>
> However doing
>
> __sysret(sys_chdir(path));
>
> instead of
>
> __syscall(chdir, path);
>
> is only three characters longer and the same amout of lines.
>
Yeah, I do like your version too, it looks consise too, the only not
comfortable part is there are dual calls in one line.
> Otherwise we would have syscall() _syscall() and __syscall() each doing
> different things.
>
Yes, I'm worried about this too, although the compilers may help a
little, but it is too later.
Just brain storming, What about another non-similar name, for example,
__syswrap() or __sysin() ?
Or even convert __sysret() to __sysout() and __syscall() to __sysin(),
do you like it? or even __sysexit(), __sysentry(), but the __sysexit()
may be misused with sys_exit().
/* Syscall return helper, set errno as -ret when ret < 0 */
static __inline__ __attribute__((unused, always_inline))
long __sysout(long ret)
{
if (ret < 0) {
SET_ERRNO(-ret);
ret = -1;
}
return ret;
}
/* Syscall call helper, use syscall name instead of syscall number */
#define __sysin(name, ...) __sysout(sys_##name(__VA_ARGS__))
static __attribute__((unused))
int brk(void *addr)
{
return __sysout(sys_brk(addr) ? 0 : -ENOMEM);
}
static __attribute__((unused))
int chdir(const char *path)
{
return __sysin(chdir, path);
}
If we really want something like __syscall()/__sysret(), I do think they
should be a pair ;-)
> And __syscall does not behave like a regular function.
>
> The rest of the patchset looks great.
>
Thanks for your nice review.
> Maybe Willy can break the tie?
>
If there is no better solution, I think your version is also a first
step to go.
>
> Thomas
>
>
> Note: If we figure out a way to build syscall() without macros I would
> like that also :-)
Yes, but it is not easy to cope with the variable number of arguments
without a macro.
BTW, do you like to convert the my_syscallN() of sys.h to the syscall()
you added? I do worry about it will make the checking of arguments
mismatch, exspecially, the checking of number of them hardly.
Best regards,
Zhangjin
Hi,
On Wed, Jun 07, 2023 at 08:34:06AM +0800, Zhangjin Wu wrote:
> > Hi Zhangjin,
> >
> > On 2023-06-06 16:17:38+0800, Zhangjin Wu wrote:
> > > Use __syscall() helper to shrink 252 lines of code.
> > >
> > > $ git show HEAD^:tools/include/nolibc/sys.h | wc -l
> > > 1425
> > > $ git show HEAD:tools/include/nolibc/sys.h | wc -l
> > > 1173
> > > $ echo "1425-1173" | bc -l
> > > 252
> > >
> > > Signed-off-by: Zhangjin Wu <[email protected]>
> > > ---
> > > tools/include/nolibc/sys.h | 336 +++++--------------------------------
> > > 1 file changed, 42 insertions(+), 294 deletions(-)
> > >
> > > diff --git a/tools/include/nolibc/sys.h b/tools/include/nolibc/sys.h
> > > index f6e3168b3e50..0cfc5157845a 100644
> > > --- a/tools/include/nolibc/sys.h
> > > +++ b/tools/include/nolibc/sys.h
> > > @@ -108,13 +108,7 @@ int sys_chdir(const char *path)
> > > static __attribute__((unused))
> > > int chdir(const char *path)
> > > {
> > > - int ret = sys_chdir(path);
> > > -
> > > - if (ret < 0) {
> > > - SET_ERRNO(-ret);
> > > - ret = -1;
> > > - }
> > > - return ret;
> > > + return __syscall(chdir, path);
> >
> > To be honest I'm still not a big fan of the __syscall macro.
> > It's a bit too magic for too little gain.
> >
> > The commit message argues that the patches make the code shorter.
> >
> > However doing
> >
> > __sysret(sys_chdir(path));
> >
> > instead of
> >
> > __syscall(chdir, path);
> >
> > is only three characters longer and the same amout of lines.
> >
>
> Yeah, I do like your version too, it looks consise too, the only not
> comfortable part is there are dual calls in one line.
For those who want to debug, having less macros or magic stuff is always
better, and in this essence I too find that Thomas' version is more
expressive about what is being done. Also, if some syscalls require a
specific handling (e.g. mmap() needs to return MAP_FAILED instead), it's
much easier to change only the code dealing with the return value and
errno setting than having to guess how to reimplement what was magically
done in a macro.
> > Otherwise we would have syscall() _syscall() and __syscall() each doing
> > different things.
> >
>
> Yes, I'm worried about this too, although the compilers may help a
> little, but it is too later.
The issue is for the person who remembers "I need to use 'syscall'" but
never remembering the number of underscores nor the variations.
> Just brain storming, What about another non-similar name, for example,
> __syswrap() or __sysin() ?
>
> Or even convert __sysret() to __sysout() and __syscall() to __sysin(),
> do you like it? or even __sysexit(), __sysentry(), but the __sysexit()
> may be misused with sys_exit().
I'd rather use "__set_errno()" to explicitly mention that it's only
used to set errno, but sysret would be fine as well IMHO as if we're
purist, it also normalizes the return value.
> /* Syscall return helper, set errno as -ret when ret < 0 */
> static __inline__ __attribute__((unused, always_inline))
> long __sysout(long ret)
> {
> if (ret < 0) {
> SET_ERRNO(-ret);
> ret = -1;
> }
> return ret;
> }
>
> /* Syscall call helper, use syscall name instead of syscall number */
> #define __sysin(name, ...) __sysout(sys_##name(__VA_ARGS__))
>
> static __attribute__((unused))
> int brk(void *addr)
> {
> return __sysout(sys_brk(addr) ? 0 : -ENOMEM);
> }
>
> static __attribute__((unused))
> int chdir(const char *path)
> {
> return __sysin(chdir, path);
> }
I still don't find this intuitive at all.
> If we really want something like __syscall()/__sysret(), I do think they
> should be a pair ;-)
Then one being called "call" while the other one being "ret" do form a
pair, no ?
Thanks,
Willy
> On Wed, Jun 07, 2023 at 08:34:06AM +0800, Zhangjin Wu wrote:
> > > Hi Zhangjin,
> > >
> > > On 2023-06-06 16:17:38+0800, Zhangjin Wu wrote:
> > > > Use __syscall() helper to shrink 252 lines of code.
> > > >
> > > > $ git show HEAD^:tools/include/nolibc/sys.h | wc -l
> > > > 1425
> > > > $ git show HEAD:tools/include/nolibc/sys.h | wc -l
> > > > 1173
> > > > $ echo "1425-1173" | bc -l
> > > > 252
> > > >
> > > > Signed-off-by: Zhangjin Wu <[email protected]>
> > > > ---
> > > > tools/include/nolibc/sys.h | 336 +++++--------------------------------
> > > > 1 file changed, 42 insertions(+), 294 deletions(-)
> > > >
> > > > diff --git a/tools/include/nolibc/sys.h b/tools/include/nolibc/sys.h
> > > > index f6e3168b3e50..0cfc5157845a 100644
> > > > --- a/tools/include/nolibc/sys.h
> > > > +++ b/tools/include/nolibc/sys.h
> > > > @@ -108,13 +108,7 @@ int sys_chdir(const char *path)
> > > > static __attribute__((unused))
> > > > int chdir(const char *path)
> > > > {
> > > > - int ret = sys_chdir(path);
> > > > -
> > > > - if (ret < 0) {
> > > > - SET_ERRNO(-ret);
> > > > - ret = -1;
> > > > - }
> > > > - return ret;
> > > > + return __syscall(chdir, path);
> > >
> > > To be honest I'm still not a big fan of the __syscall macro.
> > > It's a bit too magic for too little gain.
> > >
> > > The commit message argues that the patches make the code shorter.
> > >
> > > However doing
> > >
> > > __sysret(sys_chdir(path));
> > >
> > > instead of
> > >
> > > __syscall(chdir, path);
> > >
> > > is only three characters longer and the same amout of lines.
> > >
> >
> > Yeah, I do like your version too, it looks consise too, the only not
> > comfortable part is there are dual calls in one line.
>
> For those who want to debug, having less macros or magic stuff is always
> better, and in this essence I too find that Thomas' version is more
> expressive about what is being done. Also, if some syscalls require a
> specific handling (e.g. mmap() needs to return MAP_FAILED instead), it's
> much easier to change only the code dealing with the return value and
> errno setting than having to guess how to reimplement what was magically
> done in a macro.
>
Ok, so, let's go with Thomas' version ;-)
> > > Otherwise we would have syscall() _syscall() and __syscall() each doing
> > > different things.
> > >
> >
> > Yes, I'm worried about this too, although the compilers may help a
> > little, but it is too later.
>
> The issue is for the person who remembers "I need to use 'syscall'" but
> never remembering the number of underscores nor the variations.
Yeah, it is hard to remember.
>
> > Just brain storming, What about another non-similar name, for example,
> > __syswrap() or __sysin() ?
> >
> > Or even convert __sysret() to __sysout() and __syscall() to __sysin(),
> > do you like it? or even __sysexit(), __sysentry(), but the __sysexit()
> > may be misused with sys_exit().
>
> I'd rather use "__set_errno()" to explicitly mention that it's only
> used to set errno, but sysret would be fine as well IMHO as if we're
> purist, it also normalizes the return value.
>
Ok, let's take the shorter sysret() seems no similar sys_xxx calls.
> > /* Syscall return helper, set errno as -ret when ret < 0 */
> > static __inline__ __attribute__((unused, always_inline))
> > long __sysout(long ret)
> > {
> > if (ret < 0) {
> > SET_ERRNO(-ret);
> > ret = -1;
> > }
> > return ret;
> > }
> >
> > /* Syscall call helper, use syscall name instead of syscall number */
> > #define __sysin(name, ...) __sysout(sys_##name(__VA_ARGS__))
> >
> > static __attribute__((unused))
> > int brk(void *addr)
> > {
> > return __sysout(sys_brk(addr) ? 0 : -ENOMEM);
> > }
> >
> > static __attribute__((unused))
> > int chdir(const char *path)
> > {
> > return __sysin(chdir, path);
> > }
>
> I still don't find this intuitive at all.
>
> > If we really want something like __syscall()/__sysret(), I do think they
> > should be a pair ;-)
>
> Then one being called "call" while the other one being "ret" do form a
> pair, no ?
The 'ret' currently is a part of our old '__syscall', seems not that like a
'pair', it differs from entry/exit ;-)
As a summary, will use 'sysret()' and something like:
static __attribute__((unused))
int chdir(const char *path)
{
return sysret(chdir(path));
}
to renew the syscall helper patchset, Thanks you very much.
Best regards,
Zhangjin
>
> Thanks,
> Willy
Hi Zhangjin,
On 2023-06-07 13:39:20+0800, Zhangjin Wu wrote:
>
> As a summary, will use 'sysret()' and something like:
>
> static __attribute__((unused))
> int chdir(const char *path)
> {
> return sysret(chdir(path));
> }
>
> to renew the syscall helper patchset, Thanks you very much.
But please to use the "__" prefix.
Otherwise it could conflict with user code.
Thomas
> Hi Zhangjin,
>
> On 2023-06-07 13:39:20+0800, Zhangjin Wu wrote:
> >
> > As a summary, will use 'sysret()' and something like:
> >
> > static __attribute__((unused))
> > int chdir(const char *path)
> > {
> > return sysret(chdir(path));
> > }
> >
> > to renew the syscall helper patchset, Thanks you very much.
>
> But please to use the "__" prefix.
> Otherwise it could conflict with user code.
>
Ok, not yet to modify the code, will reserve the '__sysret()' and convert the
left parts to this style: '__sysret(chdir(path))', a simple sed script may help
to do so.
Thanks a lot.
Zhangjin
> Thomas
From: Zhangjin Wu
> Sent: 07 June 2023 06:39
...
> As a summary, will use 'sysret()' and something like:
>
> static __attribute__((unused))
> int chdir(const char *path)
> {
> return sysret(chdir(path));
> }
>
> to renew the syscall helper patchset, Thanks you very much.
While I'm all for using 'cpp-magic' to abstract and (hopefully)
simplify things. Token-pasting the sys_ here doesn't seem to gain
anything.
Anyone grepping the code for 'sys_chdir' is also going to
wonder where it is used.
There might be scope for something like:
#define syscall_wrapper(func, type) \
static __attribute__((unused)) \
int func(type *arg) \
{ \
return sysret(sys_#func(arg)); \
}
and then:
syscall_wrapper(chdir, const char *)
would expand to the code above.
I think you'd need separate defines for each number of arguments.
David
-
Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK
Registration No: 1397386 (Wales)
From: David Laight
> Sent: 10 June 2023 17:34
>
> From: Zhangjin Wu
> > Sent: 07 June 2023 06:39
> ...
> > As a summary, will use 'sysret()' and something like:
> >
> > static __attribute__((unused))
> > int chdir(const char *path)
> > {
> > return sysret(chdir(path));
> > }
> >
> > to renew the syscall helper patchset, Thanks you very much.
>
> While I'm all for using 'cpp-magic' to abstract and (hopefully)
> simplify things. Token-pasting the sys_ here doesn't seem to gain
> anything.
> Anyone grepping the code for 'sys_chdir' is also going to
> wonder where it is used.
I think I've spotted a later version of the patch
that doesn't paste the sys_
> There might be scope for something like:
> #define syscall_wrapper(func, type) \
> static __attribute__((unused)) \
> int func(type *arg) \
> { \
> return sysret(sys_#func(arg)); \
> }
> and then:
> syscall_wrapper(chdir, const char *)
> would expand to the code above.
>
> I think you'd need separate defines for each number of arguments.
It is also worth pointing out that once the 'static unused'
functions have been defined, all the #define 'goop' used to
define them can be summarily #undef'ed.
That (mostly) solves the namespace problem.
David
-
Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK
Registration No: 1397386 (Wales)