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Diffstat (limited to 'lib/canonicalize-lgpl.c')
| -rw-r--r-- | lib/canonicalize-lgpl.c | 472 |
1 files changed, 472 insertions, 0 deletions
diff --git a/lib/canonicalize-lgpl.c b/lib/canonicalize-lgpl.c new file mode 100644 index 0000000..a7fa7fe --- /dev/null +++ b/lib/canonicalize-lgpl.c @@ -0,0 +1,472 @@ +/* Return the canonical absolute name of a given file. + Copyright (C) 1996-2022 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library 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 + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, see + <https://www.gnu.org/licenses/>. */ + +#ifndef _LIBC +/* Don't use __attribute__ __nonnull__ in this compilation unit. Otherwise gcc + optimizes away the name == NULL test below. */ +# define _GL_ARG_NONNULL(params) + +# include <libc-config.h> +#endif + +/* Specification. */ +#include <stdlib.h> + +#include <errno.h> +#include <fcntl.h> +#include <limits.h> +#include <stdbool.h> +#include <string.h> +#include <sys/stat.h> +#include <unistd.h> + +#include <eloop-threshold.h> +#include <filename.h> +#include <idx.h> +#include <intprops.h> +#include <scratch_buffer.h> + +#ifdef _LIBC +# include <shlib-compat.h> +# define GCC_LINT 1 +# define _GL_ATTRIBUTE_PURE __attribute__ ((__pure__)) +#else +# define __canonicalize_file_name canonicalize_file_name +# define __realpath realpath +# include "pathmax.h" +# define __faccessat faccessat +# if defined _WIN32 && !defined __CYGWIN__ +# define __getcwd _getcwd +# elif HAVE_GETCWD +# if IN_RELOCWRAPPER + /* When building the relocatable program wrapper, use the system's getcwd + function, not the gnulib override, otherwise we would get a link error. + */ +# undef getcwd +# endif +# if defined VMS && !defined getcwd + /* We want the directory in Unix syntax, not in VMS syntax. + The gnulib override of 'getcwd' takes 2 arguments; the original VMS + 'getcwd' takes 3 arguments. */ +# define __getcwd(buf, max) getcwd (buf, max, 0) +# else +# define __getcwd getcwd +# endif +# else +# define __getcwd(buf, max) getwd (buf) +# endif +# define __mempcpy mempcpy +# define __pathconf pathconf +# define __rawmemchr rawmemchr +# define __readlink readlink +# if IN_RELOCWRAPPER + /* When building the relocatable program wrapper, use the system's memmove + function, not the gnulib override, otherwise we would get a link error. + */ +# undef memmove +# endif +#endif + +/* Suppress bogus GCC -Wmaybe-uninitialized warnings. */ +#if defined GCC_LINT || defined lint +# define IF_LINT(Code) Code +#else +# define IF_LINT(Code) /* empty */ +#endif + +#ifndef DOUBLE_SLASH_IS_DISTINCT_ROOT +# define DOUBLE_SLASH_IS_DISTINCT_ROOT false +#endif + +#if defined _LIBC || !FUNC_REALPATH_WORKS + +/* Return true if FILE's existence can be shown, false (setting errno) + otherwise. Follow symbolic links. */ +static bool +file_accessible (char const *file) +{ +# if defined _LIBC || HAVE_FACCESSAT + return __faccessat (AT_FDCWD, file, F_OK, AT_EACCESS) == 0; +# else + struct stat st; + return stat (file, &st) == 0 || errno == EOVERFLOW; +# endif +} + +/* True if concatenating END as a suffix to a file name means that the + code needs to check that the file name is that of a searchable + directory, since the canonicalize_filename_mode_stk code won't + check this later anyway when it checks an ordinary file name + component within END. END must either be empty, or start with a + slash. */ + +static bool _GL_ATTRIBUTE_PURE +suffix_requires_dir_check (char const *end) +{ + /* If END does not start with a slash, the suffix is OK. */ + while (ISSLASH (*end)) + { + /* Two or more slashes act like a single slash. */ + do + end++; + while (ISSLASH (*end)); + + switch (*end++) + { + default: return false; /* An ordinary file name component is OK. */ + case '\0': return true; /* Trailing "/" is trouble. */ + case '.': break; /* Possibly "." or "..". */ + } + /* Trailing "/.", or "/.." even if not trailing, is trouble. */ + if (!*end || (*end == '.' && (!end[1] || ISSLASH (end[1])))) + return true; + } + + return false; +} + +/* Append this to a file name to test whether it is a searchable directory. + On POSIX platforms "/" suffices, but "/./" is sometimes needed on + macOS 10.13 <https://bugs.gnu.org/30350>, and should also work on + platforms like AIX 7.2 that need at least "/.". */ + +# if defined _LIBC || defined LSTAT_FOLLOWS_SLASHED_SYMLINK +static char const dir_suffix[] = "/"; +# else +static char const dir_suffix[] = "/./"; +# endif + +/* Return true if DIR is a searchable dir, false (setting errno) otherwise. + DIREND points to the NUL byte at the end of the DIR string. + Store garbage into DIREND[0 .. strlen (dir_suffix)]. */ + +static bool +dir_check (char *dir, char *dirend) +{ + strcpy (dirend, dir_suffix); + return file_accessible (dir); +} + +static idx_t +get_path_max (void) +{ +# ifdef PATH_MAX + long int path_max = PATH_MAX; +# else + /* The caller invoked realpath with a null RESOLVED, even though + PATH_MAX is not defined as a constant. The glibc manual says + programs should not do this, and POSIX says the behavior is undefined. + Historically, glibc here used the result of pathconf, or 1024 if that + failed; stay consistent with this (dubious) historical practice. */ + int err = errno; + long int path_max = __pathconf ("/", _PC_PATH_MAX); + __set_errno (err); +# endif + return path_max < 0 ? 1024 : path_max <= IDX_MAX ? path_max : IDX_MAX; +} + +/* Act like __realpath (see below), with an additional argument + rname_buf that can be used as temporary storage. + + If GCC_LINT is defined, do not inline this function with GCC 10.1 + and later, to avoid creating a pointer to the stack that GCC + -Wreturn-local-addr incorrectly complains about. See: + https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93644 + Although the noinline attribute can hurt performance a bit, no better way + to pacify GCC is known; even an explicit #pragma does not pacify GCC. + When the GCC bug is fixed this workaround should be limited to the + broken GCC versions. */ +# if __GNUC_PREREQ (10, 1) +# if defined GCC_LINT || defined lint +__attribute__ ((__noinline__)) +# elif __OPTIMIZE__ && !__NO_INLINE__ +# define GCC_BOGUS_WRETURN_LOCAL_ADDR +# endif +# endif +static char * +realpath_stk (const char *name, char *resolved, + struct scratch_buffer *rname_buf) +{ + char *dest; + char const *start; + char const *end; + int num_links = 0; + + if (name == NULL) + { + /* As per Single Unix Specification V2 we must return an error if + either parameter is a null pointer. We extend this to allow + the RESOLVED parameter to be NULL in case the we are expected to + allocate the room for the return value. */ + __set_errno (EINVAL); + return NULL; + } + + if (name[0] == '\0') + { + /* As per Single Unix Specification V2 we must return an error if + the name argument points to an empty string. */ + __set_errno (ENOENT); + return NULL; + } + + struct scratch_buffer extra_buffer, link_buffer; + scratch_buffer_init (&extra_buffer); + scratch_buffer_init (&link_buffer); + scratch_buffer_init (rname_buf); + char *rname_on_stack = rname_buf->data; + char *rname = rname_on_stack; + bool end_in_extra_buffer = false; + bool failed = true; + + /* This is always zero for Posix hosts, but can be 2 for MS-Windows + and MS-DOS X:/foo/bar file names. */ + idx_t prefix_len = FILE_SYSTEM_PREFIX_LEN (name); + + if (!IS_ABSOLUTE_FILE_NAME (name)) + { + while (!__getcwd (rname, rname_buf->length)) + { + if (errno != ERANGE) + { + dest = rname; + goto error; + } + if (!scratch_buffer_grow (rname_buf)) + goto error_nomem; + rname = rname_buf->data; + } + dest = __rawmemchr (rname, '\0'); + start = name; + prefix_len = FILE_SYSTEM_PREFIX_LEN (rname); + } + else + { + dest = __mempcpy (rname, name, prefix_len); + *dest++ = '/'; + if (DOUBLE_SLASH_IS_DISTINCT_ROOT) + { + if (prefix_len == 0 /* implies ISSLASH (name[0]) */ + && ISSLASH (name[1]) && !ISSLASH (name[2])) + *dest++ = '/'; + *dest = '\0'; + } + start = name + prefix_len; + } + + for ( ; *start; start = end) + { + /* Skip sequence of multiple file name separators. */ + while (ISSLASH (*start)) + ++start; + + /* Find end of component. */ + for (end = start; *end && !ISSLASH (*end); ++end) + /* Nothing. */; + + /* Length of this file name component; it can be zero if a file + name ends in '/'. */ + idx_t startlen = end - start; + + if (startlen == 0) + break; + else if (startlen == 1 && start[0] == '.') + /* nothing */; + else if (startlen == 2 && start[0] == '.' && start[1] == '.') + { + /* Back up to previous component, ignore if at root already. */ + if (dest > rname + prefix_len + 1) + for (--dest; dest > rname && !ISSLASH (dest[-1]); --dest) + continue; + if (DOUBLE_SLASH_IS_DISTINCT_ROOT + && dest == rname + 1 && !prefix_len + && ISSLASH (*dest) && !ISSLASH (dest[1])) + dest++; + } + else + { + if (!ISSLASH (dest[-1])) + *dest++ = '/'; + + while (rname + rname_buf->length - dest + < startlen + sizeof dir_suffix) + { + idx_t dest_offset = dest - rname; + if (!scratch_buffer_grow_preserve (rname_buf)) + goto error_nomem; + rname = rname_buf->data; + dest = rname + dest_offset; + } + + dest = __mempcpy (dest, start, startlen); + *dest = '\0'; + + char *buf; + ssize_t n; + while (true) + { + buf = link_buffer.data; + idx_t bufsize = link_buffer.length; + n = __readlink (rname, buf, bufsize - 1); + if (n < bufsize - 1) + break; + if (!scratch_buffer_grow (&link_buffer)) + goto error_nomem; + } + if (0 <= n) + { + if (++num_links > __eloop_threshold ()) + { + __set_errno (ELOOP); + goto error; + } + + buf[n] = '\0'; + + char *extra_buf = extra_buffer.data; + idx_t end_idx IF_LINT (= 0); + if (end_in_extra_buffer) + end_idx = end - extra_buf; + size_t len = strlen (end); + if (INT_ADD_OVERFLOW (len, n)) + { + __set_errno (ENOMEM); + goto error_nomem; + } + while (extra_buffer.length <= len + n) + { + if (!scratch_buffer_grow_preserve (&extra_buffer)) + goto error_nomem; + extra_buf = extra_buffer.data; + } + if (end_in_extra_buffer) + end = extra_buf + end_idx; + + /* Careful here, end may be a pointer into extra_buf... */ + memmove (&extra_buf[n], end, len + 1); + name = end = memcpy (extra_buf, buf, n); + end_in_extra_buffer = true; + + if (IS_ABSOLUTE_FILE_NAME (buf)) + { + idx_t pfxlen = FILE_SYSTEM_PREFIX_LEN (buf); + + dest = __mempcpy (rname, buf, pfxlen); + *dest++ = '/'; /* It's an absolute symlink */ + if (DOUBLE_SLASH_IS_DISTINCT_ROOT) + { + if (ISSLASH (buf[1]) && !ISSLASH (buf[2]) && !pfxlen) + *dest++ = '/'; + *dest = '\0'; + } + /* Install the new prefix to be in effect hereafter. */ + prefix_len = pfxlen; + } + else + { + /* Back up to previous component, ignore if at root + already: */ + if (dest > rname + prefix_len + 1) + for (--dest; dest > rname && !ISSLASH (dest[-1]); --dest) + continue; + if (DOUBLE_SLASH_IS_DISTINCT_ROOT && dest == rname + 1 + && ISSLASH (*dest) && !ISSLASH (dest[1]) && !prefix_len) + dest++; + } + } + else if (! (suffix_requires_dir_check (end) + ? dir_check (rname, dest) + : errno == EINVAL)) + goto error; + } + } + if (dest > rname + prefix_len + 1 && ISSLASH (dest[-1])) + --dest; + if (DOUBLE_SLASH_IS_DISTINCT_ROOT && dest == rname + 1 && !prefix_len + && ISSLASH (*dest) && !ISSLASH (dest[1])) + dest++; + failed = false; + +error: + *dest++ = '\0'; + if (resolved != NULL && dest - rname <= get_path_max ()) + rname = strcpy (resolved, rname); + +error_nomem: + scratch_buffer_free (&extra_buffer); + scratch_buffer_free (&link_buffer); + + if (failed || rname == resolved) + { + scratch_buffer_free (rname_buf); + return failed ? NULL : resolved; + } + + return scratch_buffer_dupfree (rname_buf, dest - rname); +} + +/* Return the canonical absolute name of file NAME. A canonical name + does not contain any ".", ".." components nor any repeated file name + separators ('/') or symlinks. All file name components must exist. If + RESOLVED is null, the result is malloc'd; otherwise, if the + canonical name is PATH_MAX chars or more, returns null with 'errno' + set to ENAMETOOLONG; if the name fits in fewer than PATH_MAX chars, + returns the name in RESOLVED. If the name cannot be resolved and + RESOLVED is non-NULL, it contains the name of the first component + that cannot be resolved. If the name can be resolved, RESOLVED + holds the same value as the value returned. */ + +char * +__realpath (const char *name, char *resolved) +{ + #ifdef GCC_BOGUS_WRETURN_LOCAL_ADDR + #warning "GCC might issue a bogus -Wreturn-local-addr warning here." + #warning "See <https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93644>." + #endif + struct scratch_buffer rname_buffer; + return realpath_stk (name, resolved, &rname_buffer); +} +libc_hidden_def (__realpath) +versioned_symbol (libc, __realpath, realpath, GLIBC_2_3); + +#endif /* defined _LIBC || !FUNC_REALPATH_WORKS */ + + +#if SHLIB_COMPAT(libc, GLIBC_2_0, GLIBC_2_3) +char * +attribute_compat_text_section +__old_realpath (const char *name, char *resolved) +{ + if (resolved == NULL) + { + __set_errno (EINVAL); + return NULL; + } + + return __realpath (name, resolved); +} +compat_symbol (libc, __old_realpath, realpath, GLIBC_2_0); +#endif + + +char * +__canonicalize_file_name (const char *name) +{ + return __realpath (name, NULL); +} +weak_alias (__canonicalize_file_name, canonicalize_file_name) |