From: Tobias Ulmer <tu@emlix.com>
Date: Wed, 13 Nov 2013 16:31:10 +0000 (+0100)
Subject: Add "size" argument to eio.fread()
X-Git-Tag: e2factory-2.3.15rc1~388
X-Git-Url: https://git.e2factory.org/?a=commitdiff_plain;h=3610278e9ec61c027705e0707dca984a18377f58;p=e2factory.git

Add "size" argument to eio.fread()

Signed-off-by: Tobias Ulmer <tu@emlix.com>
---

diff --git a/generic/eio.lua b/generic/eio.lua
index d99c7e5..48f7716 100644
--- a/generic/eio.lua
+++ b/generic/eio.lua
@@ -135,10 +135,11 @@ end
 
 --- Read a file.
 -- @param file File object.
--- @return File data as a string, or false on error. May be up to 16K bytes
--- large and contain embedded zero's. On EOF an empty string is returned.
+-- @param size Positive number specifying how many bytes to read.
+-- @return File data as a string, or false on error. May be *up to* 'size' bytes
+-- large and contain embedded zero's. On EOF the empty string is returned.
 -- @return Error object on failure.
-function eio.fread(file)
+function eio.fread(file, size)
     local rc, re, errstring, buffer
 
     rc, re = is_eio_object(file)
@@ -146,7 +147,15 @@ function eio.fread(file)
         return false, re
     end
 
-    buffer, errstring = leio.fread(file.handle)
+    if type(size) ~= "number" then
+        return false, err.new("error reading file: size argument has wrong type")
+    end
+
+    if size <= 0 or size > 2147483648 --[[2GB]] then
+        return false, err("error reading file: size argument out of range")
+    end
+
+    buffer, errstring = leio.fread(file.handle, size)
     if not buffer then
         return false, err.new("error reading file: %s", errstring)
     end
diff --git a/generic/leio.c b/generic/leio.c
index 2e7deea..e44cbe5 100644
--- a/generic/leio.c
+++ b/generic/leio.c
@@ -148,36 +148,46 @@ eio_fwrite(lua_State *lua)
 static int
 eio_fread(lua_State *lua)
 {
-	char buf[16384];
-	size_t ret;
+	char *buf;
 	FILE *f;
+	size_t ret, sz;
 
 	f = lua_touserdata(lua, 1);
-	if (f == NULL) {
+	sz = lua_tointeger(lua, 2);
+	if (f == NULL || sz == 0) {
 		lua_pushboolean(lua, 0);
 		lua_pushstring(lua,
 		    "eio_fread: one or more arguments of wrong type/missing");
 		return 2;
 	}
 
+	buf = malloc(sz);
+	if (buf == NULL) {
+		lua_pushboolean(lua, 0);
+		lua_pushstring(lua, strerror(errno));
+		return 2;
+	}
 
-	ret = fread(buf, 1, sizeof(buf), f);
-	if (ret != sizeof(buf)) {
+	ret = fread(buf, 1, sz, f);
+	if (ret != sz) {
 		if (ferror(f)) {
-		    lua_pushboolean(lua, 0);
-		    lua_pushstring(lua, strerror(errno));
-		    return 2;
+			free(buf);
+			lua_pushboolean(lua, 0);
+			lua_pushstring(lua, strerror(errno));
+			return 2;
 		}
 
 		if (ret <= 0 && feof(f)) {
 			/* ret <= 0: do not discard data on short reads,
 			 * only signal EOF when all data is returned. */
+			free(buf);
 			lua_pushstring(lua, "");
 			return 1;
 		}
 	}
 
 	lua_pushlstring(lua, buf, ret);
+	free(buf);
 	return 1;
 }