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implement fs.copy, a file copying routine and clean up some docs in fs

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This commit is contained in:
Jeremy Baxter 2023-12-23 20:33:24 +13:00
parent ea3fb6c292
commit aa7ae1d9ac
1 changed files with 78 additions and 110 deletions
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188
lfs.c
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@ -8,6 +8,7 @@
#include <sys/stat.h>
#include <errno.h>
#include <fcntl.h>
#include <fts.h>
#include <libgen.h>
#include <stdio.h>
@ -23,13 +24,72 @@
#include "util.h"
/***
* Returns true if the given pathname exists
* in the file system, or returns false if it
* does not.
* Copies the contents of the file *source* to
* the file *target*. *target* will be overwritten
* if it already exists.
*
* This function may throw an error if the given
* pathname exceeds the system's path length
* limit (on most Linux systems this will be 4096).
* @function copy
* @usage
io.output("hello"):write("hello world")
fs.copy("hello", "world")
assert(io.input("world"):read("a") == "hello world")
* @tparam string source The source file to copy.
* @tparam string target The destination file.
*/
static int
fs_copy(lua_State *L)
{
struct stat sb;
const char *source, *target;
char readbuf[512];
ssize_t ret;
int sfd, tfd;
source = luaL_checkstring(L, 1);
target = luaL_checkstring(L, 2);
/* get the source file's mode */
if (stat(source, &sb) == -1)
return lfail(L);
sfd = open(source, O_RDONLY);
tfd = open(target, O_WRONLY | O_CREAT | O_TRUNC, sb.st_mode);
if (sfd == -1 || tfd == -1)
return lfail(L);
for (;;) {
ret = read(sfd, readbuf, 512);
switch (ret) {
case 0: /* end-of-file */
goto finish;
break;
case -1: /* error */
close(sfd);
close(tfd);
return lfail(L);
break;
}
ret = write(tfd, readbuf, ret);
if (ret == -1) {
close(sfd);
close(tfd);
return lfail(L);
}
}
finish:
close(sfd);
close(tfd);
lua_pushboolean(L, 1);
return 1;
}
/***
* Returns true if the given pathname exists
* in the file system, or false if it does not.
*
* @function exists
* @usage
@ -110,34 +170,8 @@ mkpath(char *path, mode_t mode, mode_t dir_mode)
* If *recursive* is true, creates intermediate directories
* as required; behaves as POSIX `mkdir -p` would.
*
* On success, returns true. Otherwise returns nil plus
* an error message.
*
* This function will return nil plus an error message
* if one of the following conditions are met:
*
* - A component of one of the given pathnames is not a directory
*
* - The given pathname exceeds the system's path length limit
*
* - A component of the path prefix does not exist
*
* - Search permission is denied for a component of the path prefix,
* or write permission is denied on the parent directory of the
* directory to be created.
*
* - The given pathname could not be translated as a result
* of too many symbolic links
*
* - The directory to be created resides on a read-only file system
*
* - The pathname given exists as a file
*
* - There is no space left on the file system
*
* - The current user's quota of disk blocks on the file system
* containing the parent directory of the directory to be created
* has been exhausted
* On success, returns true. Otherwise returns nil, an error
* message and a platform-dependent error code.
*
* @function mkdir
* @usage fs.mkdir("/usr/local/bin")
@ -152,7 +186,7 @@ fs_mkdir(lua_State *L)
int recursive; /* parameter 2 (boolean) */
int ret;
dir = (char *)luaL_checkstring(L, 1);
dir = strdup(luaL_checkstring(L, 1));
if (!lua_isboolean(L, 2) && !lua_isnoneornil(L, 2))
luaL_typeerror(L, 2, "boolean");
@ -178,37 +212,11 @@ fs_mkdir(lua_State *L)
* must be of the same type (that is, both directories or
* both non-directories) and must reside on the same file system.
*
* This function will return nil plus an error message
* if one of the following conditions are met:
*
* - One of the given pathnames exceeds the system's path length limit
*
* - One of the given pathnames point to a file that does not exist
*
* - An attempt was made to move a parent directory of a pathname
*
* - The current user is denied permission to perform the action
*
* - One of the given pathnames could not be translated as a result
* of too many symbolic links
*
* - A component of one of the given pathnames is not a directory
*
* - *src* is a directory, but *dest* is not
*
* - *dest* is a directory, but *src* is not
*
* - The given pathnames are on different file systems
*
* - There is no space left on the file system
*
* - The current user's quota of disk blocks on the file system
* containing the directory of *dest* has been exhausted
*
* - The directory containing *dest* resides on a read-only file system
* On success, returns true. Otherwise returns nil, an error
* message and a platform-dependent error code.
*
* @function move
* @usage fs.move("file1", "file2")
* @usage fs.move("srcfile", "destfile")
* @tparam string src The pathname of the file to move.
* @tparam string dest The destination pathname.
*/
@ -236,39 +244,8 @@ fs_move(lua_State *L)
/***
* Removes an empty directory.
*
* On success, returns true. Otherwise returns nil plus
* an error message.
*
* This function will return nil plus an error message
* if one of the following conditions are met:
*
* - A component of the given path is not a directory
*
* - The given pathname exceeds the system's path length limit
*
* - The named directory does not exist
*
* - The given pathname could not be translated as a result
* of too many symbolic links
*
* - The named directory contains files other than '.' and '..' in it
*
* - Search permission is denied for a component of the path prefix,
* or write permission is denied on the directory containing the directory
* to be removed
*
* - The directory containing the directory to be removed is marked sticky,
* and neither the containing directory nor the directory to be removed are
* owned by the current user
*
* - The directory to be removed or the directory containing it has its
* immutable or append-only flag set
*
* - The directory to be removed is the mount point for a mounted file system
*
* - The last component of the directory to be removed is a '.'
*
* - The directory to be created resides on a read-only file system
* On success, returns true. Otherwise returns nil, an error
* message and a platform-dependent error code.
*
* @function mkdir
* @usage fs.rmdir("yourdirectory")
@ -298,20 +275,10 @@ fs_rmdir(lua_State *L)
*
* If *dir* is nil, returns the current working
* directory. Otherwise, sets the current working
* directory to *dir* and returns true on success.
* directory to *dir*.
*
* This function will return nil and an error
* message if one of the following conditions are met:
*
* - One of the given pathnames exceeds the system's path length limit
*
* - The current user is denied permission to perform the action
*
* - The current working directory or *dir* no longer exists
*
* - *dir* is not nil, nor is it the name of a directory
*
* - *dir* could not be translated as a result of too many symbolic links
* On success, returns true. Otherwise returns nil, an error
* message and a platform-dependent error code.
*
* @function workdir
* @usage
@ -354,6 +321,7 @@ fs_workdir(lua_State *L)
}
static const luaL_Reg fslib[] = {
{"copy", fs_copy},
{"exists", fs_exists},
{"mkdir", fs_mkdir},
{"move", fs_move},