Re: [PATCH] Move {read,write}_all functions to a dedicated header

[Frederic Berat <fberat@redhat.com>]

On Thu, Jun 1, 2023 at 7:08 PM Siddhesh Poyarekar <siddhesh@gotplt.org> wrote:
>
> On 2023-06-01 11:55, Frédéric Bérat wrote:
> > Since these functions are used in both catgets/gencat.c and
> > malloc/memusage{,stat}.c, it make sense to move them into a dedicated
> > header where they can be inlined.
> > ---
> >   catgets/gencat.c      | 22 +-------------------
> >   include/unistd_ext.h  | 48 +++++++++++++++++++++++++++++++++++++++++++
> >   malloc/memusage.c     | 25 +---------------------
> >   malloc/memusagestat.c | 40 +-----------------------------------
> >   4 files changed, 51 insertions(+), 84 deletions(-)
> >   create mode 100644 include/unistd_ext.h
>
> This should ideally have been sent in with the rest of the series,
> otherwise it simply breaks pre-commit CI testing:
>
> https://patchwork.sourceware.org/project/glibc/patch/20230601155556.104745-1-fberat@redhat.com/
>

Arf, I will take note for later :(

> >
> > diff --git a/catgets/gencat.c b/catgets/gencat.c
> > index 826596c2e4..9cacc801b5 100644
> > --- a/catgets/gencat.c
> > +++ b/catgets/gencat.c
> > @@ -37,6 +37,7 @@
> >   #include <stdlib.h>
> >   #include <string.h>
> >   #include <unistd.h>
> > +#include <unistd_ext.h>
> >   #include <wchar.h>
> >
> >   #include "version.h"
> > @@ -838,27 +839,6 @@ invalid character: message ignored"));
> >     return current;
> >   }
> >
> > -static void
> > -write_all (int fd, const void *buffer, size_t length)
> > -{
> > -  const char *p = buffer;
> > -  const char *end = p + length;
> > -  while (p < end)
> > -    {
> > -      ssize_t ret = write (fd, p, end - p);
> > -      if (ret < 0)
> > -     error (EXIT_FAILURE, errno,
> > -            gettext ("write of %zu bytes failed after %td: %m"),
> > -            length, p - (const char *) buffer);
> > -
> > -      if (ret == 0)
> > -     error (EXIT_FAILURE, 0,
> > -            gettext ("write returned 0 after writing %td bytes of %zu"),
> > -            p - (const char *) buffer, length);
> > -      p += ret;
> > -    }
> > -}
> > -
> >   static void
> >   write_out (struct catalog *catalog, const char *output_name,
> >          const char *header_name)
> > diff --git a/include/unistd_ext.h b/include/unistd_ext.h
> > new file mode 100644
> > index 0000000000..b6ce067efb
> > --- /dev/null
> > +++ b/include/unistd_ext.h
>
> This needs a copyright header.
>

What's the rule for that ? It's a bit confusing since there isn't a
copyright header in most of the headers in "include", so I assumed it
didn't need it.

> > @@ -0,0 +1,48 @@
> > +#ifndef _UNISTD_EXT_H
> > +#define _UNISTD_EXT_H
> > +
> > +#include <error.h>
> > +#include <errno.h>
> > +#include <libintl.h>
> > +#include <unistd.h>
> > +
> > +/* Helpers used in catgets/gencat.c and malloc/memusage*.c */
> > +static inline void
> > +write_all (int fd, const void *buffer, size_t length)
> > +{
> > +  const char *p = buffer;
> > +  const char *end = p + length;
> > +  while (p < end)
> > +    {
> > +      ssize_t ret = write (fd, p, end - p);
> > +      if (ret < 0)
> > +     error (EXIT_FAILURE, errno,
> > +            gettext ("write of %zu bytes failed after %td: %m"),
> > +            length, p - (const char *) buffer);
> > +
> > +      if (ret == 0)
> > +     error (EXIT_FAILURE, 0,
> > +            gettext ("write returned 0 after writing %td bytes of %zu"),
> > +            p - (const char *) buffer, length);
> > +      p += ret;
> > +    }
> > +}
> > +
> > +static inline void
> > +read_all (int fd, void *buffer, size_t length)
> > +{
> > +  char *p = buffer;
> > +  char *end = p + length;
> > +  while (p < end)
> > +    {
> > +      ssize_t ret = read (fd, p, end - p);
> > +      if (ret < 0)
> > +     error (EXIT_FAILURE, errno,
> > +            gettext ("read of %zu bytes failed after %td: %m"),
> > +            length, p - (char *) buffer);
> > +
> > +      p += ret;
> > +    }
> > +}
> > +
> > +#endif
> > diff --git a/malloc/memusage.c b/malloc/memusage.c
> > index 53a3630651..1c6930188c 100644
> > --- a/malloc/memusage.c
> > +++ b/malloc/memusage.c
> > @@ -18,10 +18,7 @@
> >
> >   #include <assert.h>
> >   #include <dlfcn.h>
> > -#include <errno.h>
> > -#include <error.h>
> >   #include <fcntl.h>
> > -#include <libintl.h>
>
> You shouldn't remove these headers because gettext gets used despite the
> unistd_ext.h usage, resulting in an implicit, transitive dependency.
> Does it break anything if you don't remove these includes?
>

Nothing breaks if I keep these headers.
I actually removed them because they were added in the patch that
introduced write_all/read_all.
Since I moved write/read_all in the header, I removed the headers that
were introduced with them, but I admit I didn't check if they were
actually missing before that.

> >   #include <stdatomic.h>
> >   #include <stdbool.h>
> >   #include <stdio.h>
> > @@ -30,6 +27,7 @@
> >   #include <sys/mman.h>
> >   #include <sys/time.h>
> >   #include <unistd.h>
> > +#include <unistd_ext.h>
> >
> >   #include <hp-timing.h>
> >   #include <machine-sp.h>
> > @@ -145,27 +143,6 @@ peak_atomic_max (_Atomic size_t *peak, size_t val)
> >     while (! atomic_compare_exchange_weak (peak, &v, val));
> >   }
> >
> > -static void
> > -write_all (int fd, const void *buffer, size_t length)
> > -{
> > -  const char *p = buffer;
> > -  const char *end = p + length;
> > -  while (p < end)
> > -    {
> > -      ssize_t ret = write (fd, p, end - p);
> > -      if (ret < 0)
> > -     error (EXIT_FAILURE, errno,
> > -            gettext ("write of %zu bytes failed after %td: %m"),
> > -            length, p - (const char *) buffer);
> > -
> > -      if (ret == 0)
> > -     error (EXIT_FAILURE, 0,
> > -            gettext ("write returned 0 after writing %td bytes of %zu"),
> > -            p - (const char *) buffer, length);
> > -      p += ret;
> > -    }
> > -}
> > -
> >   /* Update the global data after a successful function call.  */
> >   static void
> >   update_data (struct header *result, size_t len, size_t old_len)
> > diff --git a/malloc/memusagestat.c b/malloc/memusagestat.c
> > index cc066d4af9..837b613c2b 100644
> > --- a/malloc/memusagestat.c
> > +++ b/malloc/memusagestat.c
> > @@ -29,6 +29,7 @@
> >   #include <stdlib.h>
> >   #include <string.h>
> >   #include <unistd.h>
> > +#include <unistd_ext.h>
> >   #include <stdint.h>
> >   #include <sys/param.h>
> >   #include <sys/stat.h>
> > @@ -114,45 +115,6 @@ static int time_based;
> >   static int also_total = 0;
> >
> >
> > -static void
> > -read_all (int fd, void *buffer, size_t length)
> > -{
> > -  char *p = buffer;
> > -  char *end = p + length;
> > -  while (p < end)
> > -    {
> > -      ssize_t ret = read (fd, p, end - p);
> > -      if (ret < 0)
> > -     error (EXIT_FAILURE, errno,
> > -            gettext ("read of %zu bytes failed after %td: %m"),
> > -            length, p - (char *) buffer);
> > -
> > -      p += ret;
> > -    }
> > -}
> > -
> > -static void
> > -write_all (int fd, const void *buffer, size_t length)
> > -{
> > -  const char *p = buffer;
> > -  const char *end = p + length;
> > -  while (p < end)
> > -    {
> > -      ssize_t ret = write (fd, p, end - p);
> > -      if (ret < 0)
> > -     error (EXIT_FAILURE, errno,
> > -            gettext ("write of %zu bytes failed after %td: %m"),
> > -            length, p - (const char *) buffer);
> > -
> > -      if (ret == 0)
> > -     error (EXIT_FAILURE, 0,
> > -            gettext ("write returned 0 after writing %td bytes of %zu"),
> > -            p - (const char *) buffer, length);
> > -      p += ret;
> > -    }
> > -}
> > -
> > -
> >   int
> >   main (int argc, char *argv[])
> >   {
>