Merge branch 'master' into 1.7

* Dynamically size getcwd() buffer in get_dir function

This should fix issue 42.

* Fixup: Properly respect NO_GETCWD

* Fixup: Get rid of getcwd_error, handle NO_GETCWD in a single place

doc/us/manual.html

@@ -104,7 +104,7 @@ LuaFileSystem offers the following functions:
 <dl class="reference">
     <dt><a name="attributes"></a><strong><code>lfs.attributes (filepath [, aname | atable])</code></strong></dt>
     <dd>Returns a table with the file attributes corresponding to
-    <code>filepath</code> (or <code>nil</code> followed by an error message
+    <code>filepath</code> (or <code>nil</code> followed by an error message and a system-dependent error code
     in case of error).
     If the second optional argument is given and is a string, then only the value of the
     named attribute is returned (this use is equivalent to
@@ -177,7 +177,7 @@ LuaFileSystem offers the following functions:
     Returns <code>true</code> in case of success or <code>nil</code> plus an
     error string.</dd>
 
-    <dt><a name="chdir"></a><strong><code>lfs.lock_dir(path, [seconds_stale])</code></strong></dt>
+    <dt><a name="lock_dir"></a><strong><code>lfs.lock_dir(path, [seconds_stale])</code></strong></dt>
     <dd>Creates a lockfile (called lockfile.lfs) in <code>path</code> if it does not
   exist and returns the lock. If the lock already exists checks if
   it's stale, using the second parameter (default for the second
@@ -187,7 +187,7 @@ LuaFileSystem offers the following functions:
   particular, if the lock exists and is not stale it returns the
   "File exists" message.</dd>
         
-    <dt><a name="getcwd"></a><strong><code>lfs.currentdir ()</code></strong></dt>
+    <dt><a name="currentdir"></a><strong><code>lfs.currentdir ()</code></strong></dt>
     <dd>Returns a string with the current working directory or <code>nil</code>
     plus an error string.</dd>
     
@@ -222,14 +222,14 @@ LuaFileSystem offers the following functions:
     <dt><a name="mkdir"></a><strong><code>lfs.mkdir (dirname)</code></strong></dt>
     <dd>Creates a new directory. The argument is the name of the new
     directory.<br />
-    Returns <code>true</code> if the operation was successful;
-    in case of error, it returns <code>nil</code> plus an error string.
+    Returns <code>true</code> in case of success or <code>nil</code>, an error message and
+    a system-dependent error code in case of error.
     </dd>
     
     <dt><a name="rmdir"></a><strong><code>lfs.rmdir (dirname)</code></strong></dt>
     <dd>Removes an existing directory. The argument is the name of the directory.<br />
-    Returns <code>true</code> if the operation was successful;
-    in case of error, it returns <code>nil</code> plus an error string.</dd>
+    Returns <code>true</code> in case of success or <code>nil</code>, an error message and
+    a system-dependent error code in case of error.
 
     <dt><a name="setmode"></a><strong><code>lfs.setmode (file, mode)</code></strong></dt>
     <dd>Sets the writing mode for a file. The mode string can be either <code>"binary"</code> or <code>"text"</code>.
@@ -242,6 +242,8 @@ LuaFileSystem offers the following functions:
     <dt><a name="symlinkattributes"></a><strong><code>lfs.symlinkattributes (filepath [, aname])</code></strong></dt>
     <dd>Identical to <a href="#attributes">lfs.attributes</a> except that
     it obtains information about the link itself (not the file it refers to).
+    It also adds a <strong><code>target</code></strong> field, containing
+    the file name that the symlink points to.
     On Windows this function does not yet support links, and is identical to
     <code>lfs.attributes</code>.
     </dd>
@@ -255,8 +257,8 @@ LuaFileSystem offers the following functions:
     Lua standard function <code>os.time</code>).
     If the modification time is omitted, the access time provided is used;
     if both times are omitted, the current time is used.<br />
-    Returns <code>true</code> if the operation was successful;
-    in case of error, it returns <code>nil</code> plus an error string.
+    Returns <code>true</code> in case of success or <code>nil</code>, an error message and
+    a system-dependent error code in case of error.
     </dd>
     
     <dt><a name="unlock"></a><strong><code>lfs.unlock (filehandle[, start[, length]])</code></strong></dt>

src/lfs.c

@@ -41,22 +41,26 @@
 #include <sys/stat.h>
 
 #ifdef _WIN32
-#include <direct.h>
-#include <windows.h>
-#include <io.h>
-#include <sys/locking.h>
-#ifdef __BORLANDC__
- #include <utime.h>
+  #include <direct.h>
+  #include <windows.h>
+  #include <io.h>
+  #include <sys/locking.h>
+  #ifdef __BORLANDC__
+    #include <utime.h>
+  #else
+    #include <sys/utime.h>
+  #endif
+  #include <fcntl.h>
+  /* MAX_PATH seems to be 260. Seems kind of small. Is there a better one? */
+  #define LFS_MAXPATHLEN MAX_PATH
 #else
- #include <sys/utime.h>
-#endif
-#include <fcntl.h>
-#else
-#include <unistd.h>
-#include <dirent.h>
-#include <fcntl.h>
-#include <sys/types.h>
-#include <utime.h>
+  #include <unistd.h>
+  #include <dirent.h>
+  #include <fcntl.h>
+  #include <sys/types.h>
+  #include <utime.h>
+  #include <sys/param.h> /* for MAXPATHLEN */
+  #define LFS_MAXPATHLEN MAXPATHLEN
 #endif
 
 #include <lua.h>
@@ -85,22 +89,6 @@
 #define strerror(_)     "System unable to describe the error"
 #endif
 
-/* Define 'getcwd' for systems that do not implement it */
-#ifdef NO_GETCWD
-#define getcwd(p,s)     NULL
-#define getcwd_error    "Function 'getcwd' not provided by system"
-#else
-#define getcwd_error    strerror(errno)
-  #ifdef _WIN32
-	 /* MAX_PATH seems to be 260. Seems kind of small. Is there a better one? */
-    #define LFS_MAXPATHLEN MAX_PATH
-  #else
-	/* For MAXPATHLEN: */
-    #include <sys/param.h>
-    #define LFS_MAXPATHLEN MAXPATHLEN
-  #endif
-#endif
-
 #define DIR_METATABLE "directory metatable"
 typedef struct dir_data {
         int  closed;
@@ -133,6 +121,13 @@ typedef struct dir_data {
 #define LSTAT_FUNC lstat
 #endif
 
+#ifdef _WIN32
+  #define lfs_mkdir _mkdir
+#else
+  #define lfs_mkdir(path) (mkdir((path), \
+    S_IRUSR | S_IWUSR | S_IXUSR | S_IRGRP | S_IWGRP | S_IXGRP | S_IROTH | S_IXOTH))
+#endif
+
 /*
 ** Utility functions
 */
@@ -147,12 +142,13 @@ static int pusherror(lua_State *L, const char *info)
         return 3;
 }
 
-static int pushresult(lua_State *L, int i, const char *info)
-{
-        if (i==-1)
-                return pusherror(L, info);
-        lua_pushinteger(L, i);
-        return 1;
+static int pushresult(lua_State *L, int res, const char *info) {
+  if (res == -1) {
+    return pusherror(L, info);
+  } else {
+    lua_pushboolean(L, 1);
+    return 1;
+  }
 }
 
 
@@ -178,18 +174,35 @@ static int change_dir (lua_State *L) {
 **  and a string describing the error
 */
 static int get_dir (lua_State *L) {
-  char *path;
-  /* Passing (NULL, 0) is not guaranteed to work. Use a temp buffer and size instead. */
-  char buf[LFS_MAXPATHLEN];
-  if ((path = getcwd(buf, LFS_MAXPATHLEN)) == NULL) {
+#ifdef NO_GETCWD
     lua_pushnil(L);
-    lua_pushstring(L, getcwd_error);
+    lua_pushstring(L, "Function 'getcwd' not provided by system");
     return 2;
-  }
-  else {
-    lua_pushstring(L, path);
-    return 1;
-  }
+#else
+    char *path = NULL;
+    /* Passing (NULL, 0) is not guaranteed to work. Use a temp buffer and size instead. */
+    size_t size = LFS_MAXPATHLEN; /* initial buffer size */
+    int result;
+    while (1) {
+        path = realloc(path, size);
+        if (!path) /* failed to allocate */
+            return pusherror(L, "get_dir realloc() failed");
+        if (getcwd(path, size) != NULL) {
+            /* success, push the path to the Lua stack */
+            lua_pushstring(L, path);
+            result = 1;
+            break;
+        }
+        if (errno != ERANGE) { /* unexpected error */
+            result = pusherror(L, "get_dir getcwd() failed");
+            break;
+        }
+        /* ERANGE = insufficient buffer capacity, double size and retry */
+        size *= 2;
+    }
+    free(path);
+    return result;
+#endif
 }
 
 /*
@@ -417,16 +430,20 @@ static int file_unlock (lua_State *L) {
 ** @param #2 Name of link.
 ** @param #3 True if link is symbolic (optional).
 */
-static int make_link(lua_State *L)
-{
+static int make_link (lua_State *L) {
 #ifndef _WIN32
-        const char *oldpath = luaL_checkstring(L, 1);
-        const char *newpath = luaL_checkstring(L, 2);
-        return pushresult(L,
-                (lua_toboolean(L,3) ? symlink : link)(oldpath, newpath), NULL);
+  const char *oldpath = luaL_checkstring(L, 1);
+  const char *newpath = luaL_checkstring(L, 2);
+  int res = (lua_toboolean(L,3) ? symlink : link)(oldpath, newpath);
+  if (res == -1) {
+    return pusherror(L, NULL);
+  } else {
+    lua_pushinteger(L, 0);
+    return 1;
+  }
 #else
-        errno = ENOSYS; /* = "Function not implemented" */
-        return pushresult(L, -1, "make_link is not supported on Windows");
+  errno = ENOSYS; /* = "Function not implemented" */
+  return pushresult(L, -1, "make_link is not supported on Windows");
 #endif
 }
 
@@ -436,21 +453,8 @@ static int make_link(lua_State *L)
 ** @param #1 Directory path.
 */
 static int make_dir (lua_State *L) {
-        const char *path = luaL_checkstring (L, 1);
-        int fail;
-#ifdef _WIN32
-        fail = _mkdir (path);
-#else
-        fail =  mkdir (path, S_IRUSR | S_IWUSR | S_IXUSR | S_IRGRP |
-                             S_IWGRP | S_IXGRP | S_IROTH | S_IXOTH );
-#endif
-        if (fail) {
-                lua_pushnil (L);
-        lua_pushfstring (L, "%s", strerror(errno));
-                return 2;
-        }
-        lua_pushboolean (L, 1);
-        return 1;
+  const char *path = luaL_checkstring(L, 1);
+  return pushresult(L, lfs_mkdir(path), NULL);
 }
 
 
@@ -459,18 +463,8 @@ static int make_dir (lua_State *L) {
 ** @param #1 Directory path.
 */
 static int remove_dir (lua_State *L) {
-        const char *path = luaL_checkstring (L, 1);
-        int fail;
-
-        fail = rmdir (path);
-
-        if (fail) {
-                lua_pushnil (L);
-                lua_pushfstring (L, "%s", strerror(errno));
-                return 2;
-        }
-        lua_pushboolean (L, 1);
-        return 1;
+  const char *path = luaL_checkstring(L, 1);
+  return pushresult(L, rmdir(path), NULL);
 }
 
 
@@ -657,26 +651,24 @@ static const char *mode2string (mode_t mode) {
 
 
 /*
-** Set access time and modification values for file
+** Set access time and modification values for a file.
+** @param #1 File path.
+** @param #2 Access time in seconds, current time is used if missing.
+** @param #3 Modification time in seconds, access time is used if missing.
 */
 static int file_utime (lua_State *L) {
-        const char *file = luaL_checkstring (L, 1);
-        struct utimbuf utb, *buf;
+  const char *file = luaL_checkstring(L, 1);
+  struct utimbuf utb, *buf;
 
-        if (lua_gettop (L) == 1) /* set to current date/time */
-                buf = NULL;
-        else {
-                utb.actime = (time_t)luaL_optnumber (L, 2, 0);
-                utb.modtime = (time_t) luaL_optinteger (L, 3, utb.actime);
-                buf = &utb;
-        }
-        if (utime (file, buf)) {
-                lua_pushnil (L);
-                lua_pushfstring (L, "%s", strerror (errno));
-                return 2;
-        }
-        lua_pushboolean (L, 1);
-        return 1;
+  if (lua_gettop (L) == 1) /* set to current date/time */
+    buf = NULL;
+  else {
+    utb.actime = (time_t) luaL_optnumber(L, 2, 0);
+    utb.modtime = (time_t) luaL_optinteger(L, 3, utb.actime);
+    buf = &utb;
+  }
+
+  return pushresult(L, utime(file, buf), NULL);
 }
 
 
@@ -813,7 +805,8 @@ static int _file_info_ (lua_State *L, int (*st)(const char*, STAT_STRUCT*)) {
         if (st(file, &info)) {
                 lua_pushnil(L);
                 lua_pushfstring(L, "cannot obtain information from file '%s': %s", file, strerror(errno));
-                return 2;
+                lua_pushinteger(L, errno);
+                return 3;
         }
         if (lua_isstring (L, 2)) {
                 const char *member = lua_tostring (L, 2);
@@ -827,7 +820,8 @@ static int _file_info_ (lua_State *L, int (*st)(const char*, STAT_STRUCT*)) {
                 /* member not found */
                 return luaL_error(L, "invalid attribute name '%s'", member);
         }
-        /* creates a table if none is given */
+        /* creates a table if none is given, removes extra arguments */
+        lua_settop(L, 2);
         if (!lua_istable (L, 2)) {
                 lua_newtable (L);
         }
@@ -849,11 +843,58 @@ static int file_info (lua_State *L) {
 }
 
 
+/*
+** Push the symlink target to the top of the stack.
+** Assumes the file name is at position 1 of the stack.
+** Returns 1 if successful (with the target on top of the stack),
+** 0 on failure (with stack unchanged, and errno set).
+*/
+static int push_link_target(lua_State *L) {
+#ifdef _WIN32
+        errno = ENOSYS;
+        return 0;
+#else
+        const char *file = luaL_checkstring(L, 1);
+        char *target = NULL;
+        int tsize, size = 256; /* size = initial buffer capacity */
+        while (1) {
+            target = realloc(target, size);
+            if (!target) /* failed to allocate */
+                return 0;
+            tsize = readlink(file, target, size);
+            if (tsize < 0) { /* a readlink() error occurred */
+                free(target);
+                return 0;
+            }
+            if (tsize < size)
+                break;
+            /* possibly truncated readlink() result, double size and retry */
+            size *= 2;
+        }
+        target[tsize] = '\0';
+        lua_pushlstring(L, target, tsize);
+        free(target);
+        return 1;
+#endif
+}
+
 /*
 ** Get symbolic link information using lstat.
 */
 static int link_info (lua_State *L) {
-        return _file_info_ (L, LSTAT_FUNC);
+        int ret;
+        if (lua_isstring (L, 2) && (strcmp(lua_tostring(L, 2), "target") == 0)) {
+                int ok = push_link_target(L);
+                return ok ? 1 : pusherror(L, "could not obtain link target");
+        }
+        ret = _file_info_ (L, LSTAT_FUNC);
+        if (ret == 1 && lua_type(L, -1) == LUA_TTABLE) {
+                int ok = push_link_target(L);
+                if (ok) {
+                        lua_setfield(L, -2, "target");
+                }
+        }
+        return ret;
 }
 
 

tests/test.lua

@@ -91,6 +91,8 @@ io.flush()
 if lfs.link (tmpfile, "_a_link_for_test_", true) then
   assert (lfs.attributes"_a_link_for_test_".mode == "file")
   assert (lfs.symlinkattributes"_a_link_for_test_".mode == "link")
+  assert (lfs.symlinkattributes"_a_link_for_test_".target == tmpfile)
+  assert (lfs.symlinkattributes("_a_link_for_test_", "target") == tmpfile)
   assert (lfs.link (tmpfile, "_a_hard_link_for_test_"))
   assert (lfs.attributes (tmpfile, "nlink") == 2)
   assert (os.remove"_a_link_for_test_")
@@ -130,6 +132,17 @@ for key, value in pairs(attr) do
           "lfs.attributes values not consistent")
 end
 
+-- Check that lfs.attributes accepts a table as second argument
+local attr2 = {}
+lfs.attributes(tmpfile, attr2)
+for key, value in pairs(attr2) do
+  assert (value == lfs.attributes (tmpfile, key),
+          "lfs.attributes values with table argument not consistent")
+end
+
+-- Check that extra arguments are ignored
+lfs.attributes(tmpfile, attr2, nil)
+
 -- Remove new file and directory
 assert (os.remove (tmpfile), "could not remove new file")
 assert (lfs.rmdir (tmpdir), "could not remove new directory")
@@ -139,7 +152,10 @@ io.write(".")
 io.flush()
 
 -- Trying to get attributes of a non-existent file
-assert (lfs.attributes ("this couldn't be an actual file") == nil, "could get attributes of a non-existent file")
+local attr_ok, err, errno = lfs.attributes("this couldn't be an actual file")
+assert(attr_ok == nil, "could get attributes of a non-existent file")
+assert(type(err) == "string", "failed lfs.attributes did not return an error message")
+assert(type(errno) == "number", "failed lfs.attributes did not return error code")
 assert (type(lfs.attributes (upper)) == "table", "couldn't get attributes of upper directory")
 
 io.write(".")