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Diffstat (limited to '')
| -rw-r--r-- | examples/loadables/ln.c | 236 |
1 files changed, 236 insertions, 0 deletions
diff --git a/examples/loadables/ln.c b/examples/loadables/ln.c new file mode 100644 index 0000000..874e9db --- /dev/null +++ b/examples/loadables/ln.c @@ -0,0 +1,236 @@ +/* ln - make links */ + +/* See Makefile for compilation details. */ + +/* + Copyright (C) 1999-2020 Free Software Foundation, Inc. + + This file is part of GNU Bash. + Bash is free software: you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation, either version 3 of the License, or + (at your option) any later version. + + Bash is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with Bash. If not, see <http://www.gnu.org/licenses/>. +*/ + +#include "config.h" + +#include "bashtypes.h" + +#if defined (HAVE_UNISTD_H) +# include <unistd.h> +#endif + +#include "posixstat.h" + +#include <stdio.h> +#include <errno.h> + +#include "builtins.h" +#include "shell.h" +#include "bashgetopt.h" +#include "common.h" + +#if !defined (errno) +extern int errno; +#endif + +typedef int unix_link_syscall_t PARAMS((const char *, const char *)); + +#define LN_SYMLINK 0x01 +#define LN_UNLINK 0x02 +#define LN_NOFOLLOW 0x04 + +static unix_link_syscall_t *linkfn; +static int dolink (); + +int +ln_builtin (list) + WORD_LIST *list; +{ + int rval, opt, flags; + WORD_LIST *l; + char *sdir; + struct stat sb; + + flags = 0; + reset_internal_getopt (); + while ((opt = internal_getopt (list, "fs")) != -1) + { + switch (opt) + { + case 'f': + flags |= LN_UNLINK; + break; + case 's': + flags |= LN_SYMLINK; + break; + case 'h': + case 'n': + flags |= LN_NOFOLLOW; + break; + CASE_HELPOPT; + default: + builtin_usage (); + return (EX_USAGE); + } + } + list = loptend; + + if (list == 0) + { + builtin_usage (); + return (EX_USAGE); + } + + linkfn = (flags & LN_SYMLINK) ? symlink : link; + + if (list->next == 0) /* ln target, equivalent to ln target . */ + return (dolink (list->word->word, ".", flags)); + + if (list->next->next == 0) /* ln target source */ + return (dolink (list->word->word, list->next->word->word, flags)); + + /* ln target1 target2 ... directory */ + + /* find last argument: target directory, and make sure it's an existing + directory. */ + for (l = list; l->next; l = l->next) + ; + sdir = l->word->word; + + if (stat(sdir, &sb) < 0) + { + builtin_error ("%s", sdir); + return (EXECUTION_FAILURE); + } + + if (S_ISDIR (sb.st_mode) == 0) + { + builtin_usage (); + return (EX_USAGE); + } + + for (rval = EXECUTION_SUCCESS; list != l; list = list->next) + rval += dolink (list->word->word, sdir, flags); + + return rval; +} + +static char * +mkdirpath (dir, file) + char *dir, *file; +{ + int dlen, flen; + char *ret; + + dlen = strlen (dir); + flen = strlen (file); + + ret = xmalloc (2 + dlen + flen); + + strcpy (ret, dir); + if (ret[dlen - 1] != '/') + ret[dlen++] = '/'; + strcpy (ret + dlen, file); + return ret; +} + +#if defined (HAVE_LSTAT) +# define LSTAT lstat +# define LSTAT_OR_STAT_IF(c, f, b) ((c) ? lstat((f), (b)) : stat((f), (b))) +#else +# define LSTAT stat +# define LSTAT_OR_STAT_IF(c, f, b) (stat((f), (b))) +#endif + +static int +dolink (src, dst, flags) + char *src, *dst; + int flags; +{ + struct stat ssb, dsb; + int exists; + char *dst_path, *p; + + /* If we're not doing symlinks, the source must exist and not be a + directory. */ + if ((flags & LN_SYMLINK) == 0) + { + if (stat (src, &ssb) != 0) + { + builtin_error ("%s: %s", src, strerror (errno)); + return (EXECUTION_FAILURE); + } + if (S_ISDIR (ssb.st_mode)) + { + errno = EISDIR; + builtin_error ("%s: %s", src, strerror (errno)); + return (EXECUTION_FAILURE); + } + } + + /* If the destination is a directory, create the final filename by appending + the basename of the source to the destination. */ + dst_path = 0; + if ((LSTAT_OR_STAT_IF((flags & LN_NOFOLLOW), dst, &dsb) == 0) && S_ISDIR (dsb.st_mode)) + { + if ((p = strrchr (src, '/')) == 0) + p = src; + else + p++; + + dst_path = mkdirpath (dst, p); + dst = dst_path; + } + + exists = LSTAT (dst, &dsb) == 0; + + /* If -f was specified, and the destination exists, unlink it. */ + if ((flags & LN_UNLINK) && exists && unlink (dst) != 0) + { + builtin_error ("%s: cannot unlink: %s", dst, strerror (errno)); + FREE (dst_path); + return (EXECUTION_FAILURE); + } + + /* Perform the link. */ + if ((*linkfn) (src, dst) != 0) + { + builtin_error ("cannot link %s to %s: %s", dst, src, strerror (errno)); + FREE (dst_path); + return (EXECUTION_FAILURE); + } + + FREE (dst_path); + return (EXECUTION_SUCCESS); +} + +char *ln_doc[] = { + "Link files.", + "", + "Create a new directory entry with the same modes as the original", + "file. The -f option means to unlink any existing file, permitting", + "the link to occur. The -s option means to create a symbolic link.", + "By default, ln makes hard links. Specifying -n or its synonym -h", + "causes ln to not resolve symlinks in the target file or directory.", + (char *)NULL +}; + +/* The standard structure describing a builtin command. bash keeps an array + of these structures. */ +struct builtin ln_struct = { + "ln", /* builtin name */ + ln_builtin, /* function implementing the builtin */ + BUILTIN_ENABLED, /* initial flags for builtin */ + ln_doc, /* array of long documentation strings. */ + "ln [-fhns] file1 [file2] OR ln [-fhns] file ... directory", /* usage synopsis; becomes short_doc */ + 0 /* reserved for internal use */ +}; |