hexl: handle large files and I/O errors

* lib-src/hexl.c: Include inttypes.h, for PRIxMAX etc.
Do not include ctype.h, as the code no longer uses isdigit.
(DEFAULT_GROUPING, un_flag, iso_flag, group_by): Now local to ‘main’.
(DEFAULT_BASE, endian): Remove; was not really used.
(usage): Remove; now done by ‘main’, as that’s simpler.
(progname): Now static.
(output_error, hexchar): New functions.
(main): Use them.  Simplify.  Remove "-oct", "-big-endian", and
"-little-endian" options, as they did not work and were not used.
Use SET_BINARY only on stdin, and fopen with "rb" otherwise.
Use SET_BINARY only once on stdout.
Do not assume file offsets fit in ‘long’.
If an I/O error occurs, report it and exit with nonzero status.

1 files changed, 95 insertions, 135 deletions

diff --git a/lib-src/hexl.c b/lib-src/hexl.c
index 2eef7b3a63d..2c7e8c44161 100644
--- a/lib-src/hexl.c
+++ b/lib-src/hexl.c
@@ -21,241 +21,201 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
 
 #include <config.h>
 
+#include <inttypes.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
-#include <ctype.h>
 
 #include <binary-io.h>
 
-#define DEFAULT_GROUPING        0x01
-#define DEFAULT_BASE            16
+static char *progname;
 
-int base = DEFAULT_BASE;
-bool un_flag = false, iso_flag = false, endian = true;
-int group_by = DEFAULT_GROUPING;
-char *progname;
+static _Noreturn void
+output_error (void)
+{
+  fprintf (stderr, "%s: write error\n", progname);
+  exit (EXIT_FAILURE);
+}
 
-_Noreturn void usage (void);
+static int
+hexchar (int c)
+{
+  return c - ('0' <= c && c <= '9' ? '0' : 'a' - 10);
+}
 
 int
 main (int argc, char **argv)
 {
-  register long address;
-  char string[18];
-  FILE *fp;
-
-  progname = *argv++; --argc;
+  int status = EXIT_SUCCESS;
+  int DEFAULT_GROUPING = 0x01;
+  int group_by = DEFAULT_GROUPING;
+  bool un_flag = false, iso_flag = false;
+  progname = *argv++;
 
   /*
    ** -hex              hex dump
-   ** -oct              Octal dump
    ** -group-by-8-bits
    ** -group-by-16-bits
    ** -group-by-32-bits
    ** -group-by-64-bits
    ** -iso              iso character set.
-   ** -big-endian       Big Endian
-   ** -little-endian    Little Endian
    ** -un || -de        from hexl format to binary.
    ** --                End switch list.
    ** <filename>        dump filename
    ** -         (as filename == stdin)
    */
 
-  while (*argv && *argv[0] == '-' && (*argv)[1])
+  for (; *argv && *argv[0] == '-' && (*argv)[1]; argv++)
     {
       /* A switch! */
       if (!strcmp (*argv, "--"))
         {
-          --argc; argv++;
+          argv++;
           break;
         }
       else if (!strcmp (*argv, "-un") || !strcmp (*argv, "-de"))
         {
           un_flag = true;
-          --argc; argv++;
+          SET_BINARY (fileno (stdout));
         }
       else if (!strcmp (*argv, "-hex"))
-        {
-          base = 16;
-          --argc; argv++;
-        }
+        /* Hex is the default and is only base supported.  */;
       else if (!strcmp (*argv, "-iso"))
-        {
-          iso_flag = true;
-          --argc; argv++;
-        }
-      else if (!strcmp (*argv, "-oct"))
-        {
-          base = 8;
-          --argc; argv++;
-        }
-      else if (!strcmp (*argv, "-big-endian"))
-        {
-          endian = true;
-          --argc; argv++;
-        }
-      else if (!strcmp (*argv, "-little-endian"))
-        {
-          endian = false;
-          --argc; argv++;
-        }
+        iso_flag = true;
       else if (!strcmp (*argv, "-group-by-8-bits"))
-        {
-          group_by = 0x00;
-          --argc; argv++;
-        }
+        group_by = 0x00;
       else if (!strcmp (*argv, "-group-by-16-bits"))
-        {
-          group_by = 0x01;
-          --argc; argv++;
-        }
+        group_by = 0x01;
       else if (!strcmp (*argv, "-group-by-32-bits"))
-        {
-          group_by = 0x03;
-          --argc; argv++;
-        }
+        group_by = 0x03;
       else if (!strcmp (*argv, "-group-by-64-bits"))
-        {
-          group_by = 0x07;
-          endian = false;
-          --argc; argv++;
-        }
+        group_by = 0x07;
       else
         {
           fprintf (stderr, "%s: invalid switch: \"%s\".\n", progname,
                    *argv);
-          usage ();
+          fprintf (stderr, "usage: %s [-de] [-iso]\n", progname);
+          return EXIT_FAILURE;
         }
     }
 
+  char const *filename = *argv ? *argv++ : "-";
+
   do
     {
-      if (*argv == NULL)
-        fp = stdin;
+      FILE *fp;
+
+      if (!strcmp (filename, "-"))
+        {
+          fp = stdin;
+          if (!un_flag)
+            SET_BINARY (fileno (stdin));
+        }
       else
         {
-          char *filename = *argv++;
-
-          if (!strcmp (filename, "-"))
-            fp = stdin;
-          else if ((fp = fopen (filename, "r")) == NULL)
+          fp = fopen (filename, un_flag ? "r" : "rb");
+          if (!fp)
             {
               perror (filename);
+              status = EXIT_FAILURE;
               continue;
             }
         }
 
       if (un_flag)
         {
-          SET_BINARY (fileno (stdout));
-
-          for (;;)
+          for (int c; 0 <= (c = getc (fp)); )
             {
-              int i, c = 0, d;
-              char buf[18];
-
-#define hexchar(x) (isdigit (x) ? x - '0' : x - 'a' + 10)
-
-              /* Skip 10 bytes.  */
-              if (fread (buf, 1, 10, fp) != 10)
-                break;
+              /* Skip address at start of line.  */
+              if (c != ' ')
+                continue;
 
-              for (i=0; i < 16; ++i)
+              for (int i = 0; i < 16; i++)
                 {
-                  if ((c = getc (fp)) == ' ' || c == EOF)
+                  c = getc (fp);
+                  if (c < 0 || c == ' ')
                     break;
 
-                  d = getc (fp);
-                  c = hexchar (c) * 0x10 + hexchar (d);
-                  putchar (c);
-
-                  if ((i&group_by) == group_by)
-                    getc (fp);
-                }
-
-              if (c == ' ')
-                {
-                  while ((c = getc (fp)) != '\n' && c != EOF)
-                    ;
-
-                  if (c == EOF)
-                    break;
-                }
-              else
-                {
-                  if (i < 16)
+                  int hc = hexchar (c);
+                  c = getc (fp);
+                  if (c < 0)
                     break;
+                  putchar (hc * 0x10 + hexchar (c));
 
-                  /* Skip 18 bytes.  */
-                  if (fread (buf, 1, 18, fp) != 18)
-                    break;
+                  if ((i & group_by) == group_by)
+                    {
+                      c = getc (fp);
+                      if (c < 0)
+                        break;
+                    }
                 }
+
+              while (0 <= c && c != '\n')
+                c = getc (fp);
+              if (c < 0)
+                break;
+              if (ferror (stdout))
+                output_error ();
             }
         }
       else
         {
-          SET_BINARY (fileno (fp));
-          address = 0;
+          int c = 0;
+          char string[18];
           string[0] = ' ';
           string[17] = '\0';
-          for (;;)
+          for (uintmax_t address = 0; 0 <= c; address += 0x10)
             {
-              register int i, c = 0;
-
-              for (i=0; i < 16; ++i)
+              int i;
+              for (i = 0; i < 16; i++)
                 {
-                  if ((c = getc (fp)) == EOF)
+                  if (0 <= c)
+                    c = getc (fp);
+                  if (c < 0)
                     {
                       if (!i)
                         break;
 
                       fputs ("  ", stdout);
-                      string[i+1] = '\0';
+                      string[i + 1] = '\0';
                     }
                   else
                     {
                       if (!i)
-                        printf ("%08lx: ", address + 0ul);
+                        printf ("%08"PRIxMAX": ", address);
 
-                      if (iso_flag)
-                        string[i+1] =
-                          (c < 0x20 || (c >= 0x7F && c < 0xa0)) ? '.' :c;
-                      else
-                        string[i+1] = (c < 0x20 || c >= 0x7F) ? '.' : c;
+                      string[i + 1]
+                        = (c < 0x20 || (0x7F <= c && (!iso_flag || c < 0xa0))
+                           ? '.' : c);
 
                       printf ("%02x", c + 0u);
                     }
 
-                  if ((i&group_by) == group_by)
+                  if ((i & group_by) == group_by)
                     putchar (' ');
                 }
 
               if (i)
                 puts (string);
 
-              if (c == EOF)
-                break;
-
-              address += 0x10;
-
+              if (ferror (stdout))
+                output_error ();
             }
         }
 
-      if (fp != stdin)
-        fclose (fp);
+      bool trouble = ferror (fp) != 0;
+      trouble |= fp != stdin && fclose (fp) != 0;
+      if (trouble)
+        {
+          fprintf (stderr, "%s: read error\n", progname);
+          status = EXIT_FAILURE;
+        }
 
-    } while (*argv != NULL);
-  return EXIT_SUCCESS;
-}
+      filename = *argv++;
+    }
+  while (filename);
 
-void
-usage (void)
-{
-  fprintf (stderr, "usage: %s [-de] [-iso]\n", progname);
-  exit (EXIT_FAILURE);
+  if (ferror (stdout) || fclose (stdout) != 0)
+    output_error ();
+  return status;
 }
-
-
-/* hexl.c ends here */