Make the installed pmdp file use a fingerprint

* Makefile.in (EMACS_PDMP): Use --fingerprint.

* doc/emacs/cmdargs.texi (Action Arguments): Document --fingerprint.

* src/emacs.c (load_pdump): Load the fingerprinted version of the
pdmp file (bug#42790).
(main): Support --fingerprint.

* src/pdumper.c (dump_fingerprint): Make non-static.

* src/pdumper.h: Declare dump_fingerprint.

3 files changed, 33 insertions, 3 deletions

diff --git a/src/emacs.c b/src/emacs.c
index 866e43fda94..cda7a9bf77f 100644
--- a/src/emacs.c
+++ b/src/emacs.c
@@ -133,6 +133,7 @@ extern char etext;
 #endif
 
 #include "pdumper.h"
+#include "fingerprint.h"
 #include "epaths.h"
 
 static const char emacs_version[] = PACKAGE_VERSION;
@@ -255,6 +256,7 @@ Initialization options:\n\
 #ifdef HAVE_PDUMPER
     "\
 --dump-file FILE            read dumped state from FILE\n\
+--fingerprint               output fingerprint and exit\n\
 ",
 #endif
 #if SECCOMP_USABLE
@@ -830,6 +832,8 @@ load_pdump (int argc, char **argv)
   const char *const suffix = ".pdmp";
   int result;
   char *emacs_executable = argv[0];
+  ptrdiff_t hexbuf_size;
+  char *hexbuf;
   const char *strip_suffix =
 #if defined DOS_NT || defined CYGWIN
     ".exe"
@@ -927,9 +931,15 @@ load_pdump (int argc, char **argv)
   /* Look for "emacs.pdmp" in PATH_EXEC.  We hardcode "emacs" in
      "emacs.pdmp" so that the Emacs binary still works if the user
      copies and renames it.  */
+  hexbuf_size = 2 * sizeof fingerprint;
+  hexbuf = xmalloc (hexbuf_size + 1);
+  hexbuf_digest (hexbuf, (char *)fingerprint, sizeof fingerprint);
+  hexbuf[hexbuf_size] = '\0';
   needed = (strlen (path_exec)
             + 1
             + strlen (argv0_base)
+            + 1
+            + strlen (hexbuf)
             + strlen (suffix)
             + 1);
   if (bufsize < needed)
@@ -937,8 +947,8 @@ load_pdump (int argc, char **argv)
       xfree (dump_file);
       dump_file = xpalloc (NULL, &bufsize, needed - bufsize, -1, 1);
     }
-  sprintf (dump_file, "%s%c%s%s",
-           path_exec, DIRECTORY_SEP, argv0_base, suffix);
+  sprintf (dump_file, "%s%c%s-%s%s",
+           path_exec, DIRECTORY_SEP, argv0_base, hexbuf, suffix);
 #if !defined (NS_SELF_CONTAINED)
   /* Assume the Emacs binary lives in a sibling directory as set up by
      the default installation configuration.  */
@@ -1387,6 +1397,23 @@ main (int argc, char **argv)
       exit (0);
     }
 
+#ifdef HAVE_PDUMPER
+  if (argmatch (argv, argc, "-fingerprint", "--fingerprint", 4,
+                NULL, &skip_args))
+    {
+      if (initialized)
+        {
+          dump_fingerprint ("fingerprint", (unsigned char *)fingerprint);
+          exit (0);
+        }
+      else
+        {
+          fputs ("Not initialized\n", stderr);
+          exit (1);
+        }
+    }
+#endif
+
   emacs_wd = emacs_get_current_dir_name ();
 #ifdef HAVE_PDUMPER
   if (dumped_with_pdumper_p ())
diff --git a/src/pdumper.c b/src/pdumper.c
index 11c680d77b7..977f4fb2a85 100644
--- a/src/pdumper.c
+++ b/src/pdumper.c
@@ -312,7 +312,7 @@ dump_reloc_set_offset (struct dump_reloc *reloc, dump_off offset)
     error ("dump relocation out of range");
 }
 
-static void
+void
 dump_fingerprint (char const *label,
                   unsigned char const xfingerprint[sizeof fingerprint])
 {
diff --git a/src/pdumper.h b/src/pdumper.h
index deec9af046d..bc339c42da5 100644
--- a/src/pdumper.h
+++ b/src/pdumper.h
@@ -50,6 +50,9 @@ enum { PDUMPER_NO_OBJECT = -1 };
 #define PDUMPER_REMEMBER_SCALAR(thing)                  \
   pdumper_remember_scalar (&(thing), sizeof (thing))
 
+extern void dump_fingerprint (const char *label,
+                              const unsigned char *xfingerprint);
+
 extern void pdumper_remember_scalar_impl (void *data, ptrdiff_t nbytes);
 
 INLINE void