library: Use standard major minor macros

I'm not sure why you would roll your own macros for major and minor
while the standard includes have these defined. Using our versions
causes two problems:
 - Some systems don't use this format for their minor/major
 - If the kernel proc interface becomes a 64-bit number, like
   dev_t is in the library, then our macro will need to be changed.

autoconf already had the check and as a bonus for anyone that
puts these definitions in sys/mkdev.h it handles that too.

So this is now the standard way of getting a minor/major number out of a
device id. Examining bits/sysmacros.h showed that their defines are
close to what devname.c had, except it can handle 64-bit numbers.

Signed-off-by: Craig Small <csmall@dropbear.xyz>

diff --git a/proc/devname.c b/proc/devname.c
index de9d0bb7fad712c6628b700bcc7841251bf66cb1..13b1b8a48a5d321ce4920b029338654a58ed0c94 100644 (file)
--- a/proc/devname.c
+++ b/proc/devname.c
@@ -38,17 +38,13 @@
  * dev_to_tty   top, ps
  */
 
-#if 0
+#ifdef MAJOR_IN_MKDEV
+#include <sys/mkdev.h>
+#elif defined MAJOR_IN_SYSMACROS
 #include <sys/sysmacros.h>
-#define MAJOR_OF(d) ((unsigned)major(d))
-#define MINOR_OF(d) ((unsigned)minor(d))
 #else
-#define MAJOR_OF(d) ( ((unsigned)(d)>>8u) & 0xfffu )
-#define MINOR_OF(d) ( ((unsigned)(d)&0xffu) | (((unsigned)(d)&0xfff00000u)>>12u) )
-#undef major
-#undef minor
-#define major <-- do not use -->
-#define minor <-- do not use -->
+#define major(d) ( ((unsigned)(d)>>8u) & 0xfffu )
+#define minor(d) ( ((unsigned)(d)&0xffu) | (((unsigned)(d)&0xfff00000u)>>12u) )
 #endif
 
 typedef struct tty_map_node {
@@ -139,8 +135,8 @@ static int driver_name(char *restrict const buf, unsigned maj, unsigned min){
       if(stat(buf, &sbuf) < 0) return 0;
     }
   }
-  if(min != MINOR_OF(sbuf.st_rdev)) return 0;
-  if(maj != MAJOR_OF(sbuf.st_rdev)) return 0;
+  if(min != minor(sbuf.st_rdev)) return 0;
+  if(maj != major(sbuf.st_rdev)) return 0;
   return 1;
 }
 
@@ -275,8 +271,8 @@ static int guess_name(char *restrict const buf, unsigned maj, unsigned min){
   default: return 0;
   }
   if(stat(buf, &sbuf) < 0) return 0;
-  if(min != MINOR_OF(sbuf.st_rdev)) return 0;
-  if(maj != MAJOR_OF(sbuf.st_rdev)) return 0;
+  if(min != minor(sbuf.st_rdev)) return 0;
+  if(maj != major(sbuf.st_rdev)) return 0;
   return 1;
 }
 
@@ -294,8 +290,8 @@ static int link_name(char *restrict const buf, unsigned maj, unsigned min, int p
   if(count <= 0 || count >= TTY_NAME_SIZE-1) return 0;
   buf[count] = '\0';
   if(stat(buf, &sbuf) < 0) return 0;
-  if(min != MINOR_OF(sbuf.st_rdev)) return 0;
-  if(maj != MAJOR_OF(sbuf.st_rdev)) return 0;
+  if(min != minor(sbuf.st_rdev)) return 0;
+  if(maj != major(sbuf.st_rdev)) return 0;
   return 1;
 }
 
@@ -334,10 +330,10 @@ unsigned dev_to_tty(char *restrict ret, unsigned chop, dev_t dev_t_dev, int pid,
   if(  ctty_name(tmp, pid                                        )) goto abbrev;
 #endif
   if(dev == 0u) goto no_tty;
-  if(driver_name(tmp, MAJOR_OF(dev), MINOR_OF(dev)               )) goto abbrev;
-  if(  link_name(tmp, MAJOR_OF(dev), MINOR_OF(dev), pid, "fd/2"  )) goto abbrev;
-  if( guess_name(tmp, MAJOR_OF(dev), MINOR_OF(dev)               )) goto abbrev;
-  if(  link_name(tmp, MAJOR_OF(dev), MINOR_OF(dev), pid, "fd/255")) goto abbrev;
+  if(driver_name(tmp, major(dev), minor(dev)               )) goto abbrev;
+  if(  link_name(tmp, major(dev), minor(dev), pid, "fd/2"  )) goto abbrev;
+  if( guess_name(tmp, major(dev), minor(dev)               )) goto abbrev;
+  if(  link_name(tmp, major(dev), minor(dev), pid, "fd/255")) goto abbrev;
   // fall through if unable to find a device file
 no_tty:
   strcpy(ret, chop >= 1 ? "?" : "");