From 8bb4e76704c4ec1c923ae75f806478360d51b403 Mon Sep 17 00:00:00 2001
From: Michael Kerrisk <mtk.manpages@gmail.com>
Date: Thu, 13 Oct 2016 11:49:00 +0200
Subject: [PATCH] pkeys.7: Cosmetic changes to example program

Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
---
 man7/pkeys.7 | 101 +++++++++++++++++++++++++++++++--------------------
 1 file changed, 62 insertions(+), 39 deletions(-)

diff --git a/man7/pkeys.7 b/man7/pkeys.7
index b35d16cbf..142423c63 100644
--- a/man7/pkeys.7
+++ b/man7/pkeys.7
@@ -165,81 +165,104 @@ Segmentation fault (core dumped)
 #include <stdio.h>
 #include <sys/mman.h>
 
-static inline void wrpkru(unsigned int pkru)
+static inline void
+wrpkru(unsigned int pkru)
 {
-        unsigned int eax = pkru;
-        unsigned int ecx = 0;
-        unsigned int edx = 0;
+    unsigned int eax = pkru;
+    unsigned int ecx = 0;
+    unsigned int edx = 0;
 
-        asm volatile(".byte 0x0f,0x01,0xef\n\t"
-                     : : "a" (eax), "c" (ecx), "d" (edx));
+    asm volatile(".byte 0x0f,0x01,0xef\\n\\t"
+                 : : "a" (eax), "c" (ecx), "d" (edx));
 }
 
-int pkey_set(int pkey, unsigned long rights, unsigned long flags)
+int
+pkey_set(int pkey, unsigned long rights, unsigned long flags)
 {
-    unsigned int pkru = (rights << (2*pkey));
+    unsigned int pkru = (rights << (2 * pkey));
     return wrpkru(pkru);
 }
 
-int pkey_mprotect(void *ptr, size_t size, unsigned long orig_prot, unsigned long pkey)
+int
+pkey_mprotect(void *ptr, size_t size, unsigned long orig_prot,
+              unsigned long pkey)
 {
     return syscall(SYS_pkey_mprotect, ptr, size, orig_prot, pkey);
 }
 
-int pkey_alloc(void)
+int
+pkey_alloc(void)
 {
     return syscall(SYS_pkey_alloc, 0, 0);
 }
 
-int pkey_free(unsigned long pkey)
+int
+pkey_free(unsigned long pkey)
 {
     return syscall(SYS_pkey_free, pkey);
 }
 
-int main(void)
+#define errExit(msg)    do { perror(msg); exit(EXIT_FAILURE); \\
+                           } while (0)
+
+int
+main(void)
 {
     int status;
     int pkey;
     int *buffer;
 
-    /* Allocate one page of memory: */
-    buffer = mmap(NULL, getpagesize(), PROT_READ|PROT_WRITE, MAP_ANONYMOUS|MAP_PRIVATE, -1, 0);
+    /*
+     *Allocate one page of memory
+     */
+    buffer = mmap(NULL, getpagesize(), PROT_READ | PROT_WRITE,
+                  MAP_ANONYMOUS | MAP_PRIVATE, \-1, 0);
     if (buffer == MAP_FAILED)
-	    return -ENOMEM;
-
-    /* Put some random data in to the page (still OK to touch): */
-    (*buffer) = __LINE__;
-    printf("buffer contains: %d\\n", *buffer);
-
-    /* Allocate a protection key: */
-    pkey = pkey_alloc();
-    if (pkey < 0)
-	    return pkey;
-
-    /* Disable access to any memory with "pkey" set,
-     * even though there is none right now. */
-    status = pkey_set(pkey, PKEY_DISABLE_ACCESS, 0);
-    if (status)
-	    return status;
+        errExit("mmap");
 
     /*
-     * set the protection key on "buffer":
-     * Note that it is still read/write as far as mprotect() is,
+     * Put some random data into the page (still OK to touch)
+     */
+    *buffer = __LINE__;
+    printf("buffer contains: %d\\n", *buffer);
+
+    /*
+     * Allocate a protection key:
+     */
+    pkey = pkey_alloc();
+    if (pkey == \-1)
+        errExit("pkey_alloc");
+
+    /*
+     * Disable access to any memory with "pkey" set,
+     * even though there is none right now
+     */
+    status = pkey_set(pkey, PKEY_DISABLE_ACCESS, 0);
+    if (status)
+        errExit("pkey_set");
+
+    /*
+     * Set the protection key on "buffer".
+     * Note that it is still read/write as far as mprotect() is
      * concerned and the previous pkey_set() overrides it.
      */
-    status = pkey_mprotect(buffer, getpagesize(), PROT_READ|PROT_WRITE, pkey);
-    if (status)
-	    return status;
+    status = pkey_mprotect(buffer, getpagesize(),
+                           PROT_READ | PROT_WRITE, pkey);
+    if (status == -1)
+        errExit("pkey_mprotect");
 
     printf("about to read buffer again...\\n");
-    /* this will crash, because we have disallowed access: */
+
+    /*
+     * This will crash, because we have disallowed access
+     */
     printf("buffer contains: %d\\n", *buffer);
 
     status = pkey_free(pkey);
-    if (status)
-	    return status;
+    if (status == -1)
+        errExit("pkey_free");
 
-    return 0;
+    exit(EXIT_SUCCESS);
 }
 .SH SEE ALSO
 .BR pkey_alloc (2),