Simplify by avoiding confusing use of strncpy etc.

5 files changed, 79 insertions, 116 deletions

diff --git a/lib-src/ChangeLog b/lib-src/ChangeLog
index bc7c5d7114d..449985966a4 100644
--- a/lib-src/ChangeLog
+++ b/lib-src/ChangeLog
@@ -1,3 +1,22 @@
+2012-07-10  Paul Eggert  <eggert@cs.ucla.edu>
+
+        Simplify by avoiding confusing use of strncpy etc.
+        * etags.c (write_classname, C_entries):
+        Use sprintf rather than strncpy or strncat.
+        * etags.c (consider_token, C_entries, HTML_labels, Prolog_functions)
+        (Erlang_functions, substitute, readline_internal, savenstr):
+        * movemail.c (mail_spool_name):
+        Use memcpy rather than strncpy or strncat when either will do.
+        * make-docfile.c (write_c_args):
+        Use memcmp rather than strncmp when either will do.
+        * movemail.c (pop_retr):
+        * pop.c (pop_stat, pop_list, pop_multi_first, pop_last)
+        (socket_connection, pop_getline, sendline, getok):
+        Use snprintf rather than strncpy or strncat.
+        * movemail.c (concat): Remove; no longer needed.
+        (xmalloc): Define only if needed, now that concat has gone away.
+        Return void *.  All uses changed.
+
 2012-07-09  Paul Eggert  <eggert@cs.ucla.edu>
 
         Add GCC-style 'const' attribute to functions that can use it.
diff --git a/lib-src/etags.c b/lib-src/etags.c
index 7141811239f..69200b790fb 100644
--- a/lib-src/etags.c
+++ b/lib-src/etags.c
@@ -2642,17 +2642,11 @@ write_classname (linebuffer *cn, const char *qualifier)
     }
   for (i = 1; i < cstack.nl; i++)
     {
-      char *s;
-      int slen;
-
-      s = cstack.cname[i];
+      char *s = cstack.cname[i];
       if (s == NULL)
         continue;
-      slen = strlen (s);
-      len += slen + qlen;
-      linebuffer_setlen (cn, len);
-      strncat (cn->buffer, qualifier, qlen);
-      strncat (cn->buffer, s, slen);
+      linebuffer_setlen (cn, len + qlen + strlen (s));
+      len += sprintf (cn->buffer + len, "%s%s", qualifier, s);
     }
 }
 
@@ -2867,7 +2861,7 @@ consider_token (register char *str, register int len, register int c, int *c_ext
            fvdef = fvnone;
            objdef = omethodtag;
            linebuffer_setlen (&token_name, len);
-           strncpy (token_name.buffer, str, len);
+           memcpy (token_name.buffer, str, len);
            token_name.buffer[len] = '\0';
            return TRUE;
          }
@@ -2879,10 +2873,11 @@ consider_token (register char *str, register int len, register int c, int *c_ext
      case omethodparm:
        if (parlev == 0)
          {
+           int oldlen = token_name.len;
            fvdef = fvnone;
            objdef = omethodtag;
-           linebuffer_setlen (&token_name, token_name.len + len);
-           strncat (token_name.buffer, str, len);
+           linebuffer_setlen (&token_name, oldlen + len);
+           memcpy (token_name.buffer + oldlen, str, len);
            return TRUE;
          }
        return FALSE;
@@ -3311,12 +3306,12 @@ C_entries (int c_ext, FILE *inf)
                               && nestlev > 0 && definedef == dnone)
                             /* in struct body */
                             {
+                              int len;
                               write_classname (&token_name, qualifier);
-                              linebuffer_setlen (&token_name,
-                                                 token_name.len+qlen+toklen);
-                              strcat (token_name.buffer, qualifier);
-                              strncat (token_name.buffer,
-                                       newlb.buffer + tokoff, toklen);
+                              len = token_name.len;
+                              linebuffer_setlen (&token_name, len+qlen+toklen);
+                              sprintf (token_name.buffer + len, "%s%.*s",
+                                       qualifier, toklen, newlb.buffer + tokoff);
                               token.named = TRUE;
                             }
                           else if (objdef == ocatseen)
@@ -3324,11 +3319,8 @@ C_entries (int c_ext, FILE *inf)
                             {
                               int len = strlen (objtag) + 2 + toklen;
                               linebuffer_setlen (&token_name, len);
-                              strcpy (token_name.buffer, objtag);
-                              strcat (token_name.buffer, "(");
-                              strncat (token_name.buffer,
-                                       newlb.buffer + tokoff, toklen);
-                              strcat (token_name.buffer, ")");
+                              sprintf (token_name.buffer, "%s(%.*s)",
+                                       objtag, toklen, newlb.buffer + tokoff);
                               token.named = TRUE;
                             }
                           else if (objdef == omethodtag
@@ -3352,8 +3344,8 @@ C_entries (int c_ext, FILE *inf)
                                   len -= 1;
                                 }
                               linebuffer_setlen (&token_name, len);
-                              strncpy (token_name.buffer,
-                                       newlb.buffer + off, len);
+                              memcpy (token_name.buffer,
+                                      newlb.buffer + off, len);
                               token_name.buffer[len] = '\0';
                               if (defun)
                                 while (--len >= 0)
@@ -3364,8 +3356,8 @@ C_entries (int c_ext, FILE *inf)
                           else
                             {
                               linebuffer_setlen (&token_name, toklen);
-                              strncpy (token_name.buffer,
-                                       newlb.buffer + tokoff, toklen);
+                              memcpy (token_name.buffer,
+                                      newlb.buffer + tokoff, toklen);
                               token_name.buffer[toklen] = '\0';
                               /* Name macros and members. */
                               token.named = (structdef == stagseen
@@ -5161,7 +5153,7 @@ HTML_labels (FILE *inf)
                   for (end = dbp; *end != '\0' && intoken (*end); end++)
                     continue;
                 linebuffer_setlen (&token_name, end - dbp);
-                strncpy (token_name.buffer, dbp, end - dbp);
+                memcpy (token_name.buffer, dbp, end - dbp);
                 token_name.buffer[end - dbp] = '\0';
 
                 dbp = end;
@@ -5261,7 +5253,7 @@ Prolog_functions (FILE *inf)
           else if (len + 1 > allocated)
             xrnew (last, len + 1, char);
           allocated = len + 1;
-          strncpy (last, cp, len);
+          memcpy (last, cp, len);
           last[len] = '\0';
         }
     }
@@ -5434,7 +5426,7 @@ Erlang_functions (FILE *inf)
           else if (len + 1 > allocated)
             xrnew (last, len + 1, char);
           allocated = len + 1;
-          strncpy (last, cp, len);
+          memcpy (last, cp, len);
           last[len] = '\0';
         }
     }
@@ -5817,7 +5809,7 @@ substitute (char *in, char *out, struct re_registers *regs)
       {
         dig = *out - '0';
         diglen = regs->end[dig] - regs->start[dig];
-        strncpy (t, in + regs->start[dig], diglen);
+        memcpy (t, in + regs->start[dig], diglen);
         t += diglen;
       }
     else
@@ -6040,7 +6032,7 @@ readline_internal (linebuffer *lbp, register FILE *stream)
           filebuf.size *= 2;
           xrnew (filebuf.buffer, filebuf.size, char);
         }
-      strncpy (filebuf.buffer + filebuf.len, lbp->buffer, lbp->len);
+      memcpy (filebuf.buffer + filebuf.len, lbp->buffer, lbp->len);
       filebuf.len += lbp->len;
       filebuf.buffer[filebuf.len++] = '\n';
       filebuf.buffer[filebuf.len] = '\0';
@@ -6263,7 +6255,7 @@ savenstr (const char *cp, int len)
   register char *dp;
 
   dp = xnew (len + 1, char);
-  strncpy (dp, cp, len);
+  memcpy (dp, cp, len);
   dp[len] = '\0';
   return dp;
 }
diff --git a/lib-src/make-docfile.c b/lib-src/make-docfile.c
index 99c43da97f5..bd87b5b6524 100644
--- a/lib-src/make-docfile.c
+++ b/lib-src/make-docfile.c
@@ -541,7 +541,7 @@ write_c_args (FILE *out, char *func, char *buf, int minargs, int maxargs)
 
           /* In C code, `default' is a reserved word, so we spell it
              `defalt'; demangle that here.  */
-          if (ident_length == 6 && strncmp (ident_start, "defalt", 6) == 0)
+          if (ident_length == 6 && memcmp (ident_start, "defalt", 6) == 0)
             fprintf (out, "DEFAULT");
           else
             while (ident_length-- > 0)
diff --git a/lib-src/movemail.c b/lib-src/movemail.c
index 3d994ec5a5e..b9a1be8a7f1 100644
--- a/lib-src/movemail.c
+++ b/lib-src/movemail.c
@@ -141,8 +141,9 @@ static _Noreturn void fatal (const char *s1, const char *s2, const char *s3);
 static void error (const char *s1, const char *s2, const char *s3);
 static _Noreturn void pfatal_with_name (char *name);
 static _Noreturn void pfatal_and_delete (char *name);
-static char *concat (const char *s1, const char *s2, const char *s3);
-static long *xmalloc (unsigned int size);
+#ifdef MAIL_USE_MAILLOCK
+static void *xmalloc (size_t size);
+#endif
 #ifdef MAIL_USE_POP
 static int popmail (char *mailbox, char *outfile, int preserve, char *password, int reverse_order);
 static int pop_retr (popserver server, int msgno, FILE *arg);
@@ -301,7 +302,7 @@ main (int argc, char **argv)
            inname_dirlen && !IS_DIRECTORY_SEP (inname[inname_dirlen - 1]);
            inname_dirlen--)
         continue;
-      tempname = (char *) xmalloc (inname_dirlen + sizeof "EXXXXXX");
+      tempname = xmalloc (inname_dirlen + sizeof "EXXXXXX");
 
       while (1)
         {
@@ -583,8 +584,8 @@ mail_spool_name (char *inname)
   if (stat (MAILDIR, &stat1) < 0)
     return NULL;
 
-  indir = (char *) xmalloc (fname - inname + 1);
-  strncpy (indir, inname, fname - inname);
+  indir = xmalloc (fname - inname + 1);
+  memcpy (indir, inname, fname - inname);
   indir[fname-inname] = '\0';
 
 
@@ -644,32 +645,18 @@ pfatal_and_delete (char *name)
   fatal ("%s for %s", s, name);
 }
 
-/* Return a newly-allocated string whose contents concatenate those of s1, s2, s3.  */
-
-static char *
-concat (const char *s1, const char *s2, const char *s3)
-{
-  size_t len1 = strlen (s1), len2 = strlen (s2), len3 = strlen (s3);
-  char *result = (char *) xmalloc (len1 + len2 + len3 + 1);
-
-  strcpy (result, s1);
-  strcpy (result + len1, s2);
-  strcpy (result + len1 + len2, s3);
-  *(result + len1 + len2 + len3) = 0;
-
-  return result;
-}
-
+#ifdef MAIL_USE_MAILLOCK
 /* Like malloc but get fatal error if memory is exhausted.  */
 
-static long *
-xmalloc (unsigned int size)
+static void *
+xmalloc (size_t size)
 {
-  long *result = (long *) malloc (size);
+  void *result = malloc (size);
   if (!result)
     fatal ("virtual memory exhausted", 0, 0);
   return result;
 }
+#endif
 
 /* This is the guts of the interface to the Post Office Protocol.  */
 
@@ -851,10 +838,7 @@ pop_retr (popserver server, int msgno, FILE *arg)
 
   if (pop_retrieve_first (server, msgno, &line))
     {
-      char *msg = concat ("Error from POP server: ", pop_error, "");
-      strncpy (Errmsg, msg, sizeof (Errmsg));
-      Errmsg[sizeof (Errmsg)-1] = '\0';
-      free (msg);
+      snprintf (Errmsg, sizeof Errmsg, "Error from POP server: %s", pop_error);
       return (NOTOK);
     }
 
@@ -873,10 +857,7 @@ pop_retr (popserver server, int msgno, FILE *arg)
 
   if (ret)
     {
-      char *msg = concat ("Error from POP server: ", pop_error, "");
-      strncpy (Errmsg, msg, sizeof (Errmsg));
-      Errmsg[sizeof (Errmsg)-1] = '\0';
-      free (msg);
+      snprintf (Errmsg, sizeof Errmsg, "Error from POP server: %s", pop_error);
       return (NOTOK);
     }
 
diff --git a/lib-src/pop.c b/lib-src/pop.c
index b8ed65c3eac..74054e0e1b1 100644
--- a/lib-src/pop.c
+++ b/lib-src/pop.c
@@ -340,10 +340,7 @@ pop_stat (popserver server, int *count, int *size)
   if (strncmp (fromserver, "+OK ", 4))
     {
       if (0 == strncmp (fromserver, "-ERR", 4))
-        {
-          strncpy (pop_error, fromserver, ERROR_MAX);
-          pop_error[ERROR_MAX-1] = '\0';
-        }
+        snprintf (pop_error, ERROR_MAX, "%s", fromserver);
       else
         {
           strcpy (pop_error,
@@ -444,10 +441,7 @@ pop_list (popserver server, int message, int **IDs, int **sizes)
       if (strncmp (fromserver, "+OK ", 4))
         {
           if (! strncmp (fromserver, "-ERR", 4))
-            {
-              strncpy (pop_error, fromserver, ERROR_MAX);
-              pop_error[ERROR_MAX-1] = '\0';
-            }
+            snprintf (pop_error, ERROR_MAX, "%s", fromserver);
           else
             {
               strcpy (pop_error,
@@ -686,8 +680,7 @@ pop_multi_first (popserver server, const char *command, char **response)
 
   if (0 == strncmp (*response, "-ERR", 4))
     {
-      strncpy (pop_error, *response, ERROR_MAX);
-      pop_error[ERROR_MAX-1] = '\0';
+      snprintf (pop_error, ERROR_MAX, "%s", *response);
       return (-1);
     }
   else if (0 == strncmp (*response, "+OK", 3))
@@ -860,8 +853,7 @@ pop_last (popserver server)
 
   if (! strncmp (fromserver, "-ERR", 4))
     {
-      strncpy (pop_error, fromserver, ERROR_MAX);
-      pop_error[ERROR_MAX-1] = '\0';
+      snprintf (pop_error, ERROR_MAX, "%s", fromserver);
       return (-1);
     }
   else if (strncmp (fromserver, "+OK ", 4))
@@ -1061,9 +1053,8 @@ socket_connection (char *host, int flags)
   sock = socket (PF_INET, SOCK_STREAM, 0);
   if (sock < 0)
     {
-      strcpy (pop_error, POP_SOCKET_ERROR);
-      strncat (pop_error, strerror (errno),
-               ERROR_MAX - sizeof (POP_SOCKET_ERROR));
+      snprintf (pop_error, ERROR_MAX, "%s%s",
+                POP_SOCKET_ERROR, strerror (errno));
       return (-1);
 
     }
@@ -1139,9 +1130,7 @@ socket_connection (char *host, int flags)
   if (! connect_ok)
     {
       CLOSESOCKET (sock);
-      strcpy (pop_error, CONNECT_ERROR);
-      strncat (pop_error, strerror (errno),
-               ERROR_MAX - sizeof (CONNECT_ERROR));
+      snprintf (pop_error, ERROR_MAX, "%s%s", CONNECT_ERROR, strerror (errno));
       return (-1);
 
     }
@@ -1159,9 +1148,8 @@ socket_connection (char *host, int flags)
             krb5_auth_con_free (kcontext, auth_context);
           if (kcontext)
             krb5_free_context (kcontext);
-          strcpy (pop_error, KRB_ERROR);
-          strncat (pop_error, error_message (rem),
-                   ERROR_MAX - sizeof (KRB_ERROR));
+          snprintf (pop_error, ERROR_MAX, "%s%s",
+                    KRB_ERROR, error_message (rem));
           CLOSESOCKET (sock);
           return (-1);
         }
@@ -1199,30 +1187,19 @@ socket_connection (char *host, int flags)
       krb5_free_principal (kcontext, server);
       if (rem)
         {
-          strcpy (pop_error, KRB_ERROR);
-          strncat (pop_error, error_message (rem),
-                   ERROR_MAX - sizeof (KRB_ERROR));
+          int pop_error_len = snprintf (pop_error, ERROR_MAX, "%s%s",
+                                        KRB_ERROR, error_message (rem));
 #if defined HAVE_KRB5_ERROR_TEXT
           if (err_ret && err_ret->text.length)
             {
-              strncat (pop_error, " [server says '",
-                       ERROR_MAX - strlen (pop_error) - 1);
-              strncat (pop_error, err_ret->text.data,
-                       min (ERROR_MAX - strlen (pop_error) - 1,
-                            err_ret->text.length));
-              strncat (pop_error, "']",
-                       ERROR_MAX - strlen (pop_error) - 1);
+              int errlen = err_ret->text.length;
+              snprintf (pop_error + pop_error_len, ERROR_MAX - pop_error_len,
+                        " [server says '.*%s']", errlen, err_ret->text.data);
             }
 #elif defined HAVE_KRB5_ERROR_E_TEXT
-          if (err_ret && err_ret->e_text && strlen (*err_ret->e_text))
-            {
-              strncat (pop_error, " [server says '",
-                       ERROR_MAX - strlen (pop_error) - 1);
-              strncat (pop_error, *err_ret->e_text,
-                       ERROR_MAX - strlen (pop_error) - 1);
-              strncat (pop_error, "']",
-                       ERROR_MAX - strlen (pop_error) - 1);
-            }
+          if (err_ret && err_ret->e_text && **err_ret->e_text)
+            snprintf (pop_error + pop_error_len, ERRMAX - pop_error_len,
+                      " [server says '%s']", *err_ret->e_text);
 #endif
           if (err_ret)
             krb5_free_error (kcontext, err_ret);
@@ -1243,9 +1220,7 @@ socket_connection (char *host, int flags)
       free ((char *) ticket);
       if (rem != KSUCCESS)
         {
-          strcpy (pop_error, KRB_ERROR);
-          strncat (pop_error, krb_err_txt[rem],
-                   ERROR_MAX - sizeof (KRB_ERROR));
+          snprintf (pop_error, ERROR_MAX, "%s%s", KRB_ERROR, krb_err_txt[rem]);
           CLOSESOCKET (sock);
           return (-1);
         }
@@ -1350,9 +1325,8 @@ pop_getline (popserver server, char **line)
                   server->buffer_size - server->data - 1, 0);
       if (ret < 0)
         {
-          strcpy (pop_error, GETLINE_ERROR);
-          strncat (pop_error, strerror (errno),
-                   ERROR_MAX - sizeof (GETLINE_ERROR));
+          snprintf (pop_error, ERROR_MAX, "%s%s",
+                    GETLINE_ERROR, strerror (errno));
           pop_trash (server);
           return (-1);
         }
@@ -1436,9 +1410,7 @@ sendline (popserver server, const char *line)
   if (ret < 0)
     {
       pop_trash (server);
-      strcpy (pop_error, SENDLINE_ERROR);
-      strncat (pop_error, strerror (errno),
-               ERROR_MAX - sizeof (SENDLINE_ERROR));
+      snprintf (pop_error, ERROR_MAX, "%s%s", SENDLINE_ERROR, strerror (errno));
       return (ret);
     }
 
@@ -1500,8 +1472,7 @@ getok (popserver server)
     return (0);
   else if (! strncmp (fromline, "-ERR", 4))
     {
-      strncpy (pop_error, fromline, ERROR_MAX);
-      pop_error[ERROR_MAX-1] = '\0';
+      snprintf (pop_error, ERROR_MAX, "%s", fromline);
       return (-1);
     }
   else