[patch] uname: fallbacks for -p and -i

[DJ Delorie]

This has come up a few times in the past, and I agree the right
solution is "don't use them", but popular GNU/Linux distros have
carried patches in the past (similar to the attached) and people have
gotten used to them producing *something*, and things broke when the
patches got dropped.  Canonicalizing "it's just -m" might help people
switch, too.

I am also contemplating an extension to glibc's confstr() that can
return something more specific than "uname -m" that might be more
useful but less compatible than past behavior, but I don't know if it
would make the portability situation better or worse ;-)

The patch only falls back to -m if the user explicitly asked for -p or
-i, it does not affect -a/-A.  It also does not complain if uname()
fails.

commit 396b58967e57b564bc37eed3ae4901c095967758
Author: DJ Delorie <d...@delorie.com>
Date:   Wed Nov 11 14:18:08 2026 -0500

    uname: fallbacks for -p and -i
    
    Neither -p nor -i are portable, but there should at least be a
    fallback for systems that don't have anything more specific than
    utsname.machine.  If the user has explicitly requested -p or -i,
    and no other mechanism is available to obtain such information,
    fall back to utsname.machine.

diff --git a/src/uname.c b/src/uname.c
index d41dabe49..dbc694bb7 100644
--- a/src/uname.c
+++ b/src/uname.c
@@ -311,6 +311,7 @@ int
 main (int argc, char **argv)
 {
   static char const unknown[] = "unknown";
+  struct utsname name;
 
   /* Mask indicating which elements to print. */
   unsigned int toprint = 0;
@@ -332,8 +333,6 @@ main (int argc, char **argv)
        & (PRINT_KERNEL_NAME | PRINT_NODENAME | PRINT_KERNEL_RELEASE
           | PRINT_KERNEL_VERSION | PRINT_MACHINE))
     {
-      struct utsname name;
-
       if (uname (&name) == -1)
         error (EXIT_FAILURE, errno, _("cannot get system name"));
 
@@ -379,6 +378,12 @@ main (int argc, char **argv)
             element = processor;
         }
 #endif
+      if (element == unknown && toprint != UINT_MAX)
+       {
+         /* If all else fails, try the -m value.  */
+         if (uname (&name) != -1)
+           element = name.machine;
+       }
       if (! (toprint == UINT_MAX && element == unknown))
         print_element (element, _("Processor"));
     }
@@ -404,6 +409,12 @@ main (int argc, char **argv)
             element = hardware_platform;
         }
 #endif
+      if (element == unknown && toprint != UINT_MAX)
+       {
+         /* If all else fails, try the -m value.  */
+         if (uname (&name) != -1)
+           element = name.machine;
+       }
       if (! (toprint == UINT_MAX && element == unknown))
         print_element (element, _("Hardware platform"));
     }