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Add symbolic link support to cp(1).

This commit is contained in:
Jonas 'Sortie' Termansen 2014-09-23 19:18:17 +02:00
parent 2ecd4c9086
commit b1a2817ada
1 changed files with 127 additions and 30 deletions
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157
utils/cp.cpp
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@ -68,23 +68,29 @@ const int FLAG_VERBOSE = 1 << 1;
const int FLAG_TARGET_DIR = 1 << 2;
const int FLAG_NO_TARGET_DIR = 1 << 3;
const int FLAG_UPDATE = 1 << 4;
const int FLAG_NO_DEREFERENCE = 1 << 5;
const int FLAG_DEREFERENCE = 1 << 6;
const int FLAG_DEREFERENCE_ARGUMENTS = 1 << 7;
enum symbolic_dereference
{
SYMBOLIC_DEREFERENCE_NONE,
SYMBOLIC_DEREFERENCE_ARGUMENTS,
SYMBOLIC_DEREFERENCE_ALWAYS,
SYMBOLIC_DEREFERENCE_DEFAULT,
};
bool CopyFileContents(int srcfd, const char* srcpath,
int dstfd, const char* dstpath, int flags);
bool CopyDirectoryContents(int srcfd, const char* srcpath,
int dstfd, const char* dstpath, int flags);
int dstfd, const char* dstpath, int flags,
enum symbolic_dereference symbolic_dereference);
bool CopyToDest(int srcdirfd, const char* srcrel, const char* srcpath,
int dstdirfd, const char* dstrel, const char* dstpath,
int flags);
int flags, enum symbolic_dereference symbolic_dereference);
bool CopyIntoDirectory(int srcdirfd, const char* srcrel, const char* srcpath,
int dstdirfd, const char* dstrel, const char* dstpath,
int flags);
int flags, enum symbolic_dereference symbolic_dereference);
bool CopyAmbigious(int srcdirfd, const char* srcrel, const char* srcpath,
int dstdirfd, const char* dstrel, const char* dstpath,
int flags);
int flags, enum symbolic_dereference symbolic_dereference);
bool CopyFileContents(int srcfd, const char* srcpath,
int dstfd, const char* dstpath, int flags)
@ -152,7 +158,8 @@ bool CopyFileContents(int srcfd, const char* srcpath,
}
bool CopyDirectoryContentsInner(DIR* srcdir, const char* srcpath,
DIR* dstdir, const char* dstpath, int flags)
DIR* dstdir, const char* dstpath, int flags,
enum symbolic_dereference symbolic_dereference)
{
if ( flags & FLAG_VERBOSE )
printf("`%s' -> `%s'\n", srcpath, dstpath);
@ -166,7 +173,8 @@ bool CopyDirectoryContentsInner(DIR* srcdir, const char* srcpath,
char* srcpath_new = AddElemToPath(srcpath, name);
char* dstpath_new = AddElemToPath(dstpath, name);
bool ok = CopyToDest(dirfd(srcdir), name, srcpath_new,
dirfd(dstdir), name, dstpath_new, flags);
dirfd(dstdir), name, dstpath_new, flags,
symbolic_dereference);
free(srcpath_new);
free(dstpath_new);
if ( !ok )
@ -176,7 +184,8 @@ bool CopyDirectoryContentsInner(DIR* srcdir, const char* srcpath,
}
bool CopyDirectoryContentsOuter(int srcfd, const char* srcpath,
int dstfd, const char* dstpath, int flags)
int dstfd, const char* dstpath, int flags,
enum symbolic_dereference symbolic_dereference)
{
struct stat srcst, dstst;
if ( fstat(srcfd, &srcst) < 0 )
@ -201,14 +210,15 @@ bool CopyDirectoryContentsOuter(int srcfd, const char* srcpath,
if ( !dstdir )
return error(0, errno, "fdopendir()"), closedir(srcdir), false;
bool ret = CopyDirectoryContentsInner(srcdir, srcpath, dstdir, dstpath,
flags);
flags, symbolic_dereference);
closedir(dstdir);
closedir(srcdir);
return ret;
}
bool CopyDirectoryContents(int srcfd, const char* srcpath,
int dstfd, const char* dstpath, int flags)
int dstfd, const char* dstpath, int flags,
enum symbolic_dereference symbolic_dereference)
{
int srcfd_copy = dup(srcfd);
if ( srcfd_copy < 0 )
@ -217,7 +227,8 @@ bool CopyDirectoryContents(int srcfd, const char* srcpath,
if ( dstfd_copy < 0 )
return error(0, errno, "dup"), close(srcfd_copy), false;
bool ret = CopyDirectoryContentsOuter(srcfd_copy, srcpath,
dstfd_copy, dstpath, flags);
dstfd_copy, dstpath, flags,
symbolic_dereference);
close(dstfd_copy);
close(srcfd_copy);
return ret;
@ -225,11 +236,14 @@ bool CopyDirectoryContents(int srcfd, const char* srcpath,
bool CopyToDest(int srcdirfd, const char* srcrel, const char* srcpath,
int dstdirfd, const char* dstrel, const char* dstpath,
int flags)
int flags, enum symbolic_dereference symbolic_dereference)
{
struct stat srcst;
bool ret = false;
int srcfd = openat(srcdirfd, srcrel, O_RDONLY);
int srcfd_flags = O_RDONLY;
if ( symbolic_dereference == SYMBOLIC_DEREFERENCE_NONE )
srcfd_flags |= O_SYMLINK_NOFOLLOW;
int srcfd = openat(srcdirfd, srcrel, O_RDONLY | srcfd_flags);
if ( srcfd < 0 )
{
error(0, errno, "%s", srcpath);
@ -240,7 +254,74 @@ bool CopyToDest(int srcdirfd, const char* srcrel, const char* srcpath,
error(0, errno, "stat: %s", srcpath);
return close(srcfd), false;
}
if ( S_ISDIR(srcst.st_mode) )
if ( symbolic_dereference == SYMBOLIC_DEREFERENCE_ARGUMENTS )
symbolic_dereference = SYMBOLIC_DEREFERENCE_NONE;
// TODO: I'm really not satisfied with the atomicity properties in this case.
if ( S_ISLNK(srcst.st_mode) )
{
// TODO: How to handle the update flag in this case?
struct stat dstst;
int dstst_ret = fstatat(dstdirfd, dstrel, &dstst, AT_SYMLINK_NOFOLLOW);
if ( dstst_ret < 0 && errno != ENOENT )
{
error(0, errno, "%s", dstpath);
return close(srcfd), false;
}
bool already_is_symlink = false;
if ( dstst_ret == 0 )
{
if ( S_ISLNK(dstst.st_mode) )
{
already_is_symlink = true;
}
else if ( S_ISDIR(dstst.st_mode) )
{
error(0, 0, "cannot overwrite directory `%s' with non-directory",
dstpath);
return close(srcfd), false;
}
else
{
if ( unlinkat(dstdirfd, dstrel, 0) == 0 )
{
if ( flags & FLAG_VERBOSE )
printf("removed `%s'\n", dstpath);
}
else if ( errno != ENOENT )
{
error(0, errno, "unlink: %s", dstpath);
return close(srcfd), false;
}
}
}
if ( !already_is_symlink )
{
if ( symlinkat("", dstdirfd, dstrel) < 0 )
{
error(0, errno, "creating symlink: %s", dstpath);
return close(srcfd), false;
}
}
int dstfd = openat(dstdirfd, dstrel, O_WRONLY | O_SYMLINK_NOFOLLOW);
if ( dstfd < 0 )
{
error(0, errno, "creating and opening symlink: %s", dstpath);
return close(srcfd), false;
}
if ( fstat(dstfd, &dstst) < 0 )
{
error(0, errno, "stat of symlink: %s", dstpath);
return close(dstfd), close(srcfd), false;
}
if ( !S_ISLNK(dstst.st_mode) )
{
error(0, errno, "unexpectedly not a symlink: %s", dstpath);
return close(dstfd), close(srcfd), false;
}
ret = CopyFileContents(srcfd, srcpath, dstfd, dstpath, flags);
close(dstfd);
}
else if ( S_ISDIR(srcst.st_mode) )
{
if ( !(flags & FLAG_RECURSIVE) )
{
@ -266,7 +347,8 @@ bool CopyToDest(int srcdirfd, const char* srcrel, const char* srcpath,
return close(srcfd), false;
}
}
ret = CopyDirectoryContents(srcfd, srcpath, dstfd, dstpath, flags);
ret = CopyDirectoryContents(srcfd, srcpath, dstfd, dstpath, flags,
symbolic_dereference);
close(dstfd);
}
else
@ -296,7 +378,7 @@ bool CopyToDest(int srcdirfd, const char* srcrel, const char* srcpath,
bool CopyIntoDirectory(int srcdirfd, const char* srcrel, const char* srcpath,
int dstdirfd, const char* dstrel, const char* dstpath,
int flags)
int flags, enum symbolic_dereference symbolic_dereference)
{
const char* src_basename = BaseName(srcrel);
int dstfd = openat(dstdirfd, dstrel, O_RDONLY | O_DIRECTORY);
@ -307,14 +389,15 @@ bool CopyIntoDirectory(int srcdirfd, const char* srcrel, const char* srcpath,
}
char* dstpath_new = AddElemToPath(dstpath, src_basename);
bool ret = CopyToDest(srcdirfd, srcrel, srcpath,
dstfd, src_basename, dstpath_new, flags);
dstfd, src_basename, dstpath_new,
flags, symbolic_dereference);
free(dstpath_new);
return ret;
}
bool CopyAmbigious(int srcdirfd, const char* srcrel, const char* srcpath,
int dstdirfd, const char* dstrel, const char* dstpath,
int flags)
int flags, enum symbolic_dereference symbolic_dereference)
{
struct stat dstst;
if ( fstatat(dstdirfd, dstrel, &dstst, 0) < 0 )
@ -328,10 +411,12 @@ bool CopyAmbigious(int srcdirfd, const char* srcrel, const char* srcpath,
}
if ( S_ISDIR(dstst.st_mode) )
return CopyIntoDirectory(srcdirfd, srcrel, srcpath,
dstdirfd, dstrel, dstpath, flags);
dstdirfd, dstrel, dstpath,
flags, symbolic_dereference);
else
return CopyToDest(srcdirfd, srcrel, srcpath,
dstdirfd, dstrel, dstpath, flags);
dstdirfd, dstrel, dstpath,
flags, symbolic_dereference);
}
void compact_arguments(int* argc, char*** argv)
@ -373,6 +458,7 @@ int main(int argc, char* argv[])
int flags = 0;
const char* target_directory = NULL;
const char* preserve_list = NULL;
enum symbolic_dereference symbolic_dereference = SYMBOLIC_DEREFERENCE_DEFAULT;
for ( int i = 1; i < argc; i++ )
{
const char* arg = argv[i];
@ -395,8 +481,8 @@ int main(int argc, char* argv[])
case 'o': if ( *(arg + 1) ) arg = "o"; else if ( i + 1 != argc ) argv[++i] = NULL; break;
case 's': /* ignored */ break;
#endif
case 'H': flags |= FLAG_DEREFERENCE_ARGUMENTS; break;
case 'L': flags |= FLAG_DEREFERENCE; break;
case 'H': symbolic_dereference = SYMBOLIC_DEREFERENCE_ARGUMENTS; break;
case 'L': symbolic_dereference = SYMBOLIC_DEREFERENCE_ALWAYS; break;
case 'r':
case 'R': flags |= FLAG_RECURSIVE; break;
case 'v': flags |= FLAG_VERBOSE; break;
@ -422,7 +508,7 @@ int main(int argc, char* argv[])
case 'T': flags |= FLAG_NO_TARGET_DIR; break;
case 'u': flags |= FLAG_UPDATE; break;
case 'p': preserve_list = "mode,ownership,timestamps"; break;
case 'P': flags |= FLAG_NO_DEREFERENCE; break;
case 'P': symbolic_dereference = SYMBOLIC_DEREFERENCE_NONE; break;
default:
#ifdef CP_PRETEND_TO_BE_INSTALL
fprintf(stderr, "%s (fake): unknown option, ignoring -- '%c'\n", argv0, c);
@ -438,7 +524,7 @@ int main(int argc, char* argv[])
else if ( !strcmp(arg, "--version") )
version(stdout, argv0), exit(0);
else if ( !strcmp(arg, "--dereference") )
flags |= FLAG_DEREFERENCE;
symbolic_dereference = SYMBOLIC_DEREFERENCE_ALWAYS;
else if ( !strcmp(arg, "--recursive") )
flags |= FLAG_RECURSIVE;
else if ( !strcmp(arg, "--verbose") )
@ -469,7 +555,7 @@ int main(int argc, char* argv[])
else if ( !strcmp(arg, "--update") )
flags |= FLAG_UPDATE;
else if ( !strcmp(arg, "--no-dereference") )
flags |= FLAG_NO_DEREFERENCE;
symbolic_dereference = SYMBOLIC_DEREFERENCE_NONE;
else
{
#ifdef CP_PRETEND_TO_BE_INSTALL
@ -485,6 +571,14 @@ int main(int argc, char* argv[])
if ( (flags & FLAG_TARGET_DIR) && (flags & FLAG_NO_TARGET_DIR) )
error(1, 0, "cannot combine --target-directory (-t) and --no-target-directory (-T)");
if ( symbolic_dereference == SYMBOLIC_DEREFERENCE_DEFAULT )
{
if ( flags & FLAG_RECURSIVE )
symbolic_dereference = SYMBOLIC_DEREFERENCE_NONE;
else
symbolic_dereference = SYMBOLIC_DEREFERENCE_ALWAYS;
}
// TODO: Actually preserve.
(void) preserve_list;
@ -501,7 +595,8 @@ int main(int argc, char* argv[])
const char* dst = argv[2];
if ( 3 < argc )
error(1, 0, "extra operand `%s'", argv[3]);
return CopyToDest(AT_FDCWD, src, src, AT_FDCWD, dst, dst, flags) ? 0 : 1;
return CopyToDest(AT_FDCWD, src, src, AT_FDCWD, dst, dst, flags,
symbolic_dereference) ? 0 : 1;
}
if ( !(flags & FLAG_TARGET_DIR) && argc <= 3 )
@ -512,7 +607,8 @@ int main(int argc, char* argv[])
const char* dst = argv[2];
if ( 3 < argc )
error(1, 0, "extra operand `%s'", argv[3]);
return CopyAmbigious(AT_FDCWD, src, src, AT_FDCWD, dst, dst, flags) ? 0 : 1;
return CopyAmbigious(AT_FDCWD, src, src, AT_FDCWD, dst, dst, flags,
symbolic_dereference) ? 0 : 1;
}
if ( !target_directory )
@ -529,7 +625,8 @@ int main(int argc, char* argv[])
{
const char* src = argv[i];
const char* dst = target_directory;
if ( !CopyIntoDirectory(AT_FDCWD, src, src, AT_FDCWD, dst, dst, flags) )
if ( !CopyIntoDirectory(AT_FDCWD, src, src, AT_FDCWD, dst, dst, flags,
symbolic_dereference) )
success = false;
}