(unexec): Define n so as to cause compilation error

for the code where people have often written n instead of nn.

1 files changed, 44 insertions, 39 deletions

diff --git a/src/unexelf.c b/src/unexelf.c
index 8d435f289f8..a9d1e247185 100644
--- a/src/unexelf.c
+++ b/src/unexelf.c
@@ -1183,50 +1183,55 @@ unexec (new_name, old_name, data_start, bss_start, entry_address)
   for (n = new_file_h->e_shnum - 1; n; n--)
     {
       ElfW(Shdr) section = NEW_SECTION_H (n);
-      switch (section.sh_type) {
-      default:
-        break;
-      case SHT_REL:
-      case SHT_RELA:
-        /* This code handles two different size structs, but there should
-           be no harm in that provided that r_offset is always the first
-           member.  */
-        nn = section.sh_info;
-        if (!strcmp (old_section_names + NEW_SECTION_H (nn).sh_name, ".data")
-            || !strcmp ((old_section_names + NEW_SECTION_H (nn).sh_name),
-                        ".sdata")
-            || !strcmp ((old_section_names + NEW_SECTION_H (nn).sh_name),
-                        ".lit4")
-            || !strcmp ((old_section_names + NEW_SECTION_H (nn).sh_name),
-                        ".lit8")
+
+      /* Cause a compilation error if anyone uses n instead of nn below.  */
+      struct {int a;} n;
+
+      switch (section.sh_type) 
+        {
+        default:
+          break;
+        case SHT_REL:
+        case SHT_RELA:
+          /* This code handles two different size structs, but there should
+             be no harm in that provided that r_offset is always the first
+             member.  */
+          nn = section.sh_info;
+          if (!strcmp (old_section_names + NEW_SECTION_H (nn).sh_name, ".data")
+              || !strcmp ((old_section_names + NEW_SECTION_H (nn).sh_name),
+                          ".sdata")
+              || !strcmp ((old_section_names + NEW_SECTION_H (nn).sh_name),
+                          ".lit4")
+              || !strcmp ((old_section_names + NEW_SECTION_H (nn).sh_name),
+                          ".lit8")
 #if __sgi
-            || !strcmp ((old_section_names + NEW_SECTION_H (nn).sh_name),
-                        ".got")
+              || !strcmp ((old_section_names + NEW_SECTION_H (nn).sh_name),
+                          ".got")
 #endif
-            || !strcmp ((old_section_names + NEW_SECTION_H (nn).sh_name),
-                        ".sdata1")
-            || !strcmp ((old_section_names + NEW_SECTION_H (nn).sh_name),
-                        ".data1"))
-          {
-            ElfW(Addr) offset = NEW_SECTION_H (nn).sh_addr -
-              NEW_SECTION_H (nn).sh_offset;
-            caddr_t reloc = old_base + section.sh_offset, end;
-            for (end = reloc + section.sh_size; reloc < end;
-                 reloc += section.sh_entsize)
-              {
-                ElfW(Addr) addr = ((ElfW(Rel) *) reloc)->r_offset - offset;
+              || !strcmp ((old_section_names + NEW_SECTION_H (nn).sh_name),
+                          ".sdata1")
+              || !strcmp ((old_section_names + NEW_SECTION_H (nn).sh_name),
+                          ".data1"))
+            {
+              ElfW(Addr) offset = (NEW_SECTION_H (nn).sh_addr
+                                   - NEW_SECTION_H (nn).sh_offset);
+              caddr_t reloc = old_base + section.sh_offset, end;
+              for (end = reloc + section.sh_size; reloc < end;
+                   reloc += section.sh_entsize)
+                {
+                  ElfW(Addr) addr = ((ElfW(Rel) *) reloc)->r_offset - offset;
 #ifdef __alpha__
-                /* The Alpha ELF binutils currently have a bug that
-                   sometimes results in relocs that contain all
-                   zeroes.  Work around this for now...  */
-                if (((ElfW(Rel) *) reloc)->r_offset == 0)
+                  /* The Alpha ELF binutils currently have a bug that
+                     sometimes results in relocs that contain all
+                     zeroes.  Work around this for now...  */
+                  if (((ElfW(Rel) *) reloc)->r_offset == 0)
                     continue;
 #endif
-                memcpy (new_base + addr, old_base + addr, sizeof(ElfW(Addr)));
-              }
-          }
-        break;
-      }
+                  memcpy (new_base + addr, old_base + addr, sizeof(ElfW(Addr)));
+                }
+            }
+          break;
+        }
     }
 
   /* Write out new_file, and free the buffers.  */