Fix gcc/9.3.1 and gcc/10.2.1 errors and warnings

calc.c

@@ -479,7 +479,22 @@ main(int argc, char **argv)
 				program);
 			exit(21);
 		}
-		strncpy(cmdbuf + cmdlen, cp, cplen+1);
+		/*
+		 * The next statement could be:
+		 *
+		 *	strncpy(cmdbuf + cmdlen, cp, cplen);
+		 *
+		 * however compilers like gcc would issue warnings such as:
+		 *
+		 * 	specified bound depends on the length of the
+		 * 	source argument
+		 *
+		 * even though we terminate the string by setting a NUL
+		 * byte following the copy.  Therefore we call memcpy()
+		 * instead to avoid such warnings.
+		 */
+		memcpy(cmdbuf + cmdlen, cp, cplen);
+		cmdbuf[newcmdlen] = '\0';
 		cmdlen = newcmdlen;
 		index++;
 		if (index < maxindex)

file.c

@@ -50,6 +50,8 @@
 
 #define READSIZE	1024	/* buffer size for reading */
 
+#define MIN(a,b) (((a) <= (b)) ? (a) : (b))
+
 /*
  * external STDIO functions
  */
@@ -1414,23 +1416,21 @@ z2filepos(ZVALUE zpos)
 #if FILEPOS_BITS == FULL_BITS
 	/* ztofull puts the value into native byte order */
 	pos = ztofull(zpos);
-	/* on some hosts, FILEPOS is not a scalar */
-	memset(&ret, 0, sizeof(FILEPOS));
-	memcpy((void *)&ret, (void *)&pos, sizeof(FILEPOS));
+	memset(&ret, 0, sizeof(ret));	/* on some hosts, FILEPOS is not a scalar */
+	memcpy((void *)&ret, (void *)&pos, MIN(sizeof(ret), sizeof(pos)));
 	return ret;
 #elif FILEPOS_BITS < FULL_BITS
 	/* ztofull puts the value into native byte order */
 	pos = ztolong(zpos);
-	/* on some hosts, FILEPOS is not a scalar */
-	memset(&ret, 0, sizeof(FILEPOS));
-	memcpy((void *)&ret, (void *)&pos, sizeof(pos));
+	memset(&ret, 0, sizeof(ret));	/* on some hosts, FILEPOS is not a scalar */
+	memcpy((void *)&ret, (void *)&pos, MIN(sizeof(ret), sizeof(pos)));
 	return ret;
 #else /* FILEPOS_BITS > FULL_BITS */
 	if (!zgtmaxfull(zpos)) {
 		/* ztofull puts the value into native byte order */
 		pos = ztofull(zpos);
-		memset(&ret, 0, sizeof(FILEPOS));
-		memcpy((void *)&ret, (void *)&pos, sizeof(pos));
+		memset(&ret, 0, sizeof(ret));	/* on some hosts, FILEPOS is not a scalar */
+		memcpy((void *)&ret, (void *)&pos, MIN(sizeof(ret), sizeof(pos)));
 		return ret;
 	}
 
@@ -1439,11 +1439,12 @@ z2filepos(ZVALUE zpos)
 	 */
 	if (zpos.len >= FILEPOS_BITS/BASEB) {
 		/* copy the lower FILEPOS_BITS of the ZVALUE */
-		memcpy(&tmp, zpos.v, sizeof(FILEPOS));
+		memset(&tmp, 0, sizeof(tmp));	/* on some hosts, FILEPOS is not a scalar */
+		memcpy(&tmp, zpos.v, MIN(sizeof(tmp), FILEPOS_LEN);
 	} else {
 		/* copy what bits we can into the temp value */
-		memset(&tmp, 0, sizeof(FILEPOS));
-		memcpy(&tmp, zpos.v, zpos.len*BASEB/8);
+		memset(&tmp, 0, sizeof(tmp));	/* on some hosts, FILEPOS is not a scalar */
+		memcpy(&tmp, zpos.v, MIN(sizeof(tmp), MIN(zpos.len*BASEB/8, FILEPOS_LEN)));
 	}
 	/* swap into native byte order */
 	SWAP_HALF_IN_FILEPOS(&ret, &tmp);

func.c

@@ -268,7 +268,22 @@ f_prompt(VALUE *vp)
 		math_error("Cannot allocate string");
 		/*NOTREACHED*/
 	}
-	strncpy(newcp, cp, len+1);
+	/*
+	 * The next statement could be::
+	 *
+	 *	strncpy(newcp, cp, len);
+	 *
+	 * however compilers like gcc would issue warnings such as:
+	 *
+	 * 	specified bound depends on the length of the
+	 * 	source argument
+	 *
+	 * even though we terminate the string by setting a NUL
+	 * byte following the copy.  Therefore we call memcpy()
+	 * instead to avoid such warnings.
+	 */
+	memcpy(newcp, cp, len);
+	newcp[len] = '\0';
 	result.v_str = makestring(newcp);
 	return result;
 }
@@ -7446,7 +7461,26 @@ f_cmdbuf(void)
 
 	cmdbuf_len = strlen(cmdbuf);
 	newcp = (char *)malloc(cmdbuf_len+1);
-	strncpy(newcp, cmdbuf, cmdbuf_len+1);
+	if (newcp == NULL) {
+		math_error("Cannot allocate string in cmdbuf");
+		/*NOTREACHED*/
+	}
+	/*
+	 * The next statement could be::
+	 *
+	 *	strncpy(newcp, cmdbuf, cmdbuf_len);
+	 *
+	 * however compilers like gcc would issue warnings such as:
+	 *
+	 * 	specified bound depends on the length of the
+	 * 	source argument
+	 *
+	 * even though we terminate the string by setting a NUL
+	 * byte following the copy.  Therefore we call memcpy()
+	 * instead to avoid such warnings.
+	 */
+	memcpy(newcp, cmdbuf, cmdbuf_len);
+	newcp[cmdbuf_len] = '\0';
 	result.v_str = makestring(newcp);
 	return result;
 }
@@ -7624,17 +7658,35 @@ f_putenv(int count, VALUE **vals)
 
 		/* convert putenv("foo","bar") into putenv("foo=bar") */
 		snprintf_len = vals[0]->v_str->s_len + 1 +
-                               vals[1]->v_str->s_len + 1;
+                               vals[1]->v_str->s_len;
 		putenv_str = (char *)malloc(snprintf_len+1);
 		if (putenv_str == NULL) {
 			math_error("Cannot allocate string in putenv");
 			/*NOTREACHED*/
 		}
-		snprintf(putenv_str, snprintf_len,
-			"%s=%s", vals[0]->v_str->s_str,
-			vals[1]->v_str->s_str);
-		putenv_str[snprintf_len] = '\0';	/* paranoia */
-
+		/*
+		 * The next statement could be::
+		 *
+		 *	snprintf(putenv_str, snprintf_len,
+		 *	        "%s=%s", vals[0]->v_str->s_str,
+		 *	        vals[1]->v_str->s_str);
+		 *
+		 * however compilers like gcc would issue warnings such as:
+		 *
+		 * 	null destination pointer
+		 *
+		 * even though we check that putenv_str is non-NULL
+		 * above before using it.  Therefore we call memcpy()
+		 * twice and make an assignment instead to avoid such warnings.
+		 */
+		memcpy(putenv_str,
+		       vals[0]->v_str->s_str,
+		       vals[0]->v_str->s_len);
+		putenv_str[vals[0]->v_str->s_len] = '=';
+		memcpy(putenv_str + vals[0]->v_str->s_len + 1,
+		       vals[1]->v_str->s_str,
+		       vals[1]->v_str->s_len);
+		putenv_str[snprintf_len] = '\0';
 
 	} else {
 		/* firewall */
@@ -7658,8 +7710,8 @@ f_putenv(int count, VALUE **vals)
 			math_error("Cannot allocate string in putenv");
 			/*NOTREACHED*/
 		}
-		strncpy(putenv_str, vals[0]->v_str->s_str,
-			vals[0]->v_str->s_len + 1);
+		memcpy(putenv_str, vals[0]->v_str->s_str, vals[0]->v_str->s_len);
+		putenv_str[vals[0]->v_str->s_len] = '\0';
 	}
 
 	/* return putenv result */

input.c

@@ -442,7 +442,23 @@ homeexpand(char *name)
 			if (fullpath == NULL) {
 				return NULL;
 			}
-			strncpy(fullpath, ent->pw_dir, fullpath_len+1);
+			/*
+			 * The next statement could be:
+			 *
+			 *	strncpy(fullpath, ent->pw_dir, fullpath_len);
+			 *
+			 * however compilers like gcc would issue warnings
+			 * such as:
+			 *
+			 * 	specified bound depends on the length of the
+			 * 	source argument
+			 *
+			 * even though we terminate the string by setting a NUL
+			 * byte following the copy.  Therefore we call memcpy()
+			 * instead to avoid such warnings.
+			 */
+			memcpy(fullpath, ent->pw_dir, fullpath_len);
+			fullpath[fullpath_len] = '\0';
 			return fullpath;
 		}
 		username = (char *) malloc(after-name + 1 + 1);

version.c

@@ -131,8 +131,22 @@ version(void)
 		fprintf(stderr, "%s: cannot malloc version string\n", program);
 		exit(70);
 	}
-	strncpy(stored_version, verbuf, len);
-	stored_version[len] = '\0';	/* paranoia */
+	/*
+	 * The next statement could be:
+	 *
+	 *	strncpy(stored_version, verbuf, len);
+	 *
+	 * however compilers like gcc would issue warnings such as:
+	 *
+	 * 	specified bound depends on the length of the
+	 * 	source argument
+	 *
+	 * even though we terminate the string by setting a NUL
+	 * byte following the copy.  Therefore we call memcpy()
+	 * instead to avoid such warnings.
+	 */
+	memcpy(stored_version, verbuf, len);
+	stored_version[len] = '\0';
 
 	/*
 	 * return the newly malloced buffer