diff options
Diffstat (limited to 'gnulib/import/canonicalize-lgpl.c')
| -rw-r--r-- | gnulib/import/canonicalize-lgpl.c | 495 |
1 files changed, 267 insertions, 228 deletions
diff --git a/gnulib/import/canonicalize-lgpl.c b/gnulib/import/canonicalize-lgpl.c index 9f990988393..4bb4c0c2d96 100644 --- a/gnulib/import/canonicalize-lgpl.c +++ b/gnulib/import/canonicalize-lgpl.c @@ -1,19 +1,20 @@ /* Return the canonical absolute name of a given file. - Copyright (C) 1996-2020 Free Software Foundation, Inc. + Copyright (C) 1996-2021 Free Software Foundation, Inc. This file is part of the GNU C Library. - This program 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. + The GNU C Library 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. - This program is distributed in the hope that it will be useful, + 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 General Public License for more details. + 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 this program. If not, see <https://www.gnu.org/licenses/>. */ + You should have received a copy of the GNU 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 @@ -21,38 +22,38 @@ # define _GL_ARG_NONNULL(params) # define _GL_USE_STDLIB_ALLOC 1 -# include <config.h> +# include <libc-config.h> #endif -#if !HAVE_CANONICALIZE_FILE_NAME || !FUNC_REALPATH_WORKS || defined _LIBC - /* Specification. */ #include <stdlib.h> -#include <alloca.h> -#include <string.h> -#include <unistd.h> +#include <errno.h> +#include <fcntl.h> #include <limits.h> -#if HAVE_SYS_PARAM_H || defined _LIBC -# include <sys/param.h> -#endif +#include <stdbool.h> +#include <string.h> #include <sys/stat.h> -#include <errno.h> -#include <stddef.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 SHLIB_COMPAT(lib, introduced, obsoleted) 0 -# define versioned_symbol(lib, local, symbol, version) extern int dummy -# define compat_symbol(lib, local, symbol, version) -# define weak_alias(local, symbol) # define __canonicalize_file_name canonicalize_file_name # define __realpath realpath # include "pathmax.h" -# include "malloca.h" -# include "filename.h" -# if HAVE_GETCWD +# 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. @@ -70,57 +71,137 @@ # else # define __getcwd(buf, max) getwd (buf) # endif +# define __mempcpy mempcpy +# define __pathconf pathconf +# define __rawmemchr rawmemchr # define __readlink readlink -# define __set_errno(e) errno = (e) -# ifndef MAXSYMLINKS -# ifdef SYMLOOP_MAX -# define MAXSYMLINKS SYMLOOP_MAX -# else -# define MAXSYMLINKS 20 -# endif -# endif +# define __stat stat #endif -#ifndef DOUBLE_SLASH_IS_DISTINCT_ROOT -# define DOUBLE_SLASH_IS_DISTINCT_ROOT 0 +/* Suppress bogus GCC -Wmaybe-uninitialized warnings. */ +#if defined GCC_LINT || defined lint +# define IF_LINT(Code) Code +#else +# define IF_LINT(Code) /* empty */ #endif -/* Define this independently so that stdint.h is not a prerequisite. */ -#ifndef SIZE_MAX -# define SIZE_MAX ((size_t) -1) +#ifndef DOUBLE_SLASH_IS_DISTINCT_ROOT +# define DOUBLE_SLASH_IS_DISTINCT_ROOT false #endif -#if !FUNC_REALPATH_WORKS || defined _LIBC +#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 +} -static void -alloc_failed (void) +/* 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 defined _WIN32 && ! defined __CYGWIN__ - /* Avoid errno problem without using the malloc or realloc modules; see: - https://lists.gnu.org/r/bug-gnulib/2016-08/msg00025.html */ - errno = ENOMEM; + /* 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); } -/* Return the canonical absolute name of file NAME. A canonical name - does not contain any ".", ".." components nor any repeated path - separators ('/') or symlinks. All path 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 path of the first component - that cannot be resolved. If the path can be resolved, RESOLVED - holds the same value as the value returned. */ +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; +} -char * -__realpath (const char *name, char *resolved) +/* 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 *rpath, *dest, *extra_buf = NULL; - const char *start, *end, *rpath_limit; - long int path_max; + char *dest; + char const *start; + char const *end; int num_links = 0; - size_t prefix_len; if (name == NULL) { @@ -140,205 +221,148 @@ __realpath (const char *name, char *resolved) return NULL; } -#ifdef PATH_MAX - path_max = PATH_MAX; -#else - path_max = pathconf (name, _PC_PATH_MAX); - if (path_max <= 0) - path_max = 8192; -#endif - - if (resolved == NULL) - { - rpath = malloc (path_max); - if (rpath == NULL) - { - alloc_failed (); - return NULL; - } - } - else - rpath = resolved; - rpath_limit = rpath + path_max; + 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. */ - prefix_len = FILE_SYSTEM_PREFIX_LEN (name); + idx_t prefix_len = FILE_SYSTEM_PREFIX_LEN (name); if (!IS_ABSOLUTE_FILE_NAME (name)) { - if (!__getcwd (rpath, path_max)) + while (!__getcwd (rname, rname_buf->length)) { - rpath[0] = '\0'; - goto error; + if (errno != ERANGE) + { + dest = rname; + goto error; + } + if (!scratch_buffer_grow (rname_buf)) + goto error_nomem; + rname = rname_buf->data; } - dest = strchr (rpath, '\0'); + dest = __rawmemchr (rname, '\0'); start = name; - prefix_len = FILE_SYSTEM_PREFIX_LEN (rpath); + prefix_len = FILE_SYSTEM_PREFIX_LEN (rname); } else { - dest = rpath; - if (prefix_len) - { - memcpy (rpath, name, prefix_len); - dest += prefix_len; - } + dest = __mempcpy (rname, name, prefix_len); *dest++ = '/'; if (DOUBLE_SLASH_IS_DISTINCT_ROOT) { - if (ISSLASH (name[1]) && !ISSLASH (name[2]) && !prefix_len) + if (prefix_len == 0 /* implies ISSLASH (name[0]) */ + && ISSLASH (name[1]) && !ISSLASH (name[2])) *dest++ = '/'; *dest = '\0'; } start = name + prefix_len; } - for (end = start; *start; start = end) + for ( ; *start; start = end) { -#ifdef _LIBC - struct stat64 st; -#else - struct stat st; -#endif - - /* Skip sequence of multiple path-separators. */ + /* Skip sequence of multiple file name separators. */ while (ISSLASH (*start)) ++start; - /* Find end of path component. */ + /* Find end of component. */ for (end = start; *end && !ISSLASH (*end); ++end) /* Nothing. */; - if (end - start == 0) + /* 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 (end - start == 1 && start[0] == '.') + else if (startlen == 1 && start[0] == '.') /* nothing */; - else if (end - start == 2 && start[0] == '.' && start[1] == '.') + else if (startlen == 2 && start[0] == '.' && start[1] == '.') { /* Back up to previous component, ignore if at root already. */ - if (dest > rpath + prefix_len + 1) - for (--dest; dest > rpath && !ISSLASH (dest[-1]); --dest) + if (dest > rname + prefix_len + 1) + for (--dest; dest > rname && !ISSLASH (dest[-1]); --dest) continue; if (DOUBLE_SLASH_IS_DISTINCT_ROOT - && dest == rpath + 1 && !prefix_len + && dest == rname + 1 && !prefix_len && ISSLASH (*dest) && !ISSLASH (dest[1])) dest++; } else { - size_t new_size; - if (!ISSLASH (dest[-1])) *dest++ = '/'; - if (dest + (end - start) >= rpath_limit) + while (rname + rname_buf->length - dest + < startlen + sizeof dir_suffix) { - ptrdiff_t dest_offset = dest - rpath; - char *new_rpath; - - if (resolved) - { - __set_errno (ENAMETOOLONG); - if (dest > rpath + prefix_len + 1) - dest--; - *dest = '\0'; - goto error; - } - new_size = rpath_limit - rpath; - if (end - start + 1 > path_max) - new_size += end - start + 1; - else - new_size += path_max; - new_rpath = (char *) realloc (rpath, new_size); - if (new_rpath == NULL) - { - alloc_failed (); - goto error; - } - rpath = new_rpath; - rpath_limit = rpath + new_size; - - dest = rpath + dest_offset; + idx_t dest_offset = dest - rname; + if (!scratch_buffer_grow_preserve (rname_buf)) + goto error_nomem; + rname = rname_buf->data; + dest = rname + dest_offset; } -#ifdef _LIBC - dest = __mempcpy (dest, start, end - start); -#else - memcpy (dest, start, end - start); - dest += end - start; -#endif + dest = __mempcpy (dest, start, startlen); *dest = '\0'; - /* FIXME: if lstat fails with errno == EOVERFLOW, - the entry exists. */ -#ifdef _LIBC - if (__lxstat64 (_STAT_VER, rpath, &st) < 0) -#else - if (lstat (rpath, &st) < 0) -#endif - goto error; - - if (S_ISLNK (st.st_mode)) + char *buf; + ssize_t n; + while (true) { - char *buf; - size_t len; - ssize_t n; - - if (++num_links > MAXSYMLINKS) + 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 = malloca (path_max); - if (!buf) - { - __set_errno (ENOMEM); - goto error; - } - - n = __readlink (rpath, buf, path_max - 1); - if (n < 0) - { - int saved_errno = errno; - freea (buf); - __set_errno (saved_errno); - goto error; - } buf[n] = '\0'; - if (!extra_buf) + 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)) { - extra_buf = malloca (path_max); - if (!extra_buf) - { - freea (buf); - __set_errno (ENOMEM); - goto error; - } + __set_errno (ENOMEM); + goto error_nomem; } - - len = strlen (end); - /* Check that n + len + 1 doesn't overflow and is <= path_max. */ - if (n >= SIZE_MAX - len || n + len >= path_max) + while (extra_buffer.length <= len + n) { - freea (buf); - __set_errno (ENAMETOOLONG); - goto error; + 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)) { - size_t pfxlen = FILE_SYSTEM_PREFIX_LEN (buf); + idx_t pfxlen = FILE_SYSTEM_PREFIX_LEN (buf); - if (pfxlen) - memcpy (rpath, buf, pfxlen); - dest = rpath + pfxlen; + dest = __mempcpy (rname, buf, pfxlen); *dest++ = '/'; /* It's an absolute symlink */ if (DOUBLE_SLASH_IS_DISTINCT_ROOT) { @@ -353,44 +377,67 @@ __realpath (const char *name, char *resolved) { /* Back up to previous component, ignore if at root already: */ - if (dest > rpath + prefix_len + 1) - for (--dest; dest > rpath && !ISSLASH (dest[-1]); --dest) + if (dest > rname + prefix_len + 1) + for (--dest; dest > rname && !ISSLASH (dest[-1]); --dest) continue; - if (DOUBLE_SLASH_IS_DISTINCT_ROOT && dest == rpath + 1 + if (DOUBLE_SLASH_IS_DISTINCT_ROOT && dest == rname + 1 && ISSLASH (*dest) && !ISSLASH (dest[1]) && !prefix_len) dest++; } } - else if (!S_ISDIR (st.st_mode) && *end != '\0') - { - __set_errno (ENOTDIR); - goto error; - } + else if (! (suffix_requires_dir_check (end) + ? dir_check (rname, dest) + : errno == EINVAL)) + goto error; } } - if (dest > rpath + prefix_len + 1 && ISSLASH (dest[-1])) + if (dest > rname + prefix_len + 1 && ISSLASH (dest[-1])) --dest; - if (DOUBLE_SLASH_IS_DISTINCT_ROOT && dest == rpath + 1 && !prefix_len + if (DOUBLE_SLASH_IS_DISTINCT_ROOT && dest == rname + 1 && !prefix_len && ISSLASH (*dest) && !ISSLASH (dest[1])) dest++; - *dest = '\0'; + failed = false; - if (extra_buf) - freea (extra_buf); +error: + *dest++ = '\0'; + if (resolved != NULL && dest - rname <= get_path_max ()) + rname = strcpy (resolved, rname); - return rpath; +error_nomem: + scratch_buffer_free (&extra_buffer); + scratch_buffer_free (&link_buffer); -error: - { - int saved_errno = errno; - if (extra_buf) - freea (extra_buf); - if (resolved == NULL) - free (rpath); - __set_errno (saved_errno); - } - return NULL; + 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 /* !FUNC_REALPATH_WORKS || defined _LIBC */ @@ -418,11 +465,3 @@ __canonicalize_file_name (const char *name) return __realpath (name, NULL); } weak_alias (__canonicalize_file_name, canonicalize_file_name) - -#else - -/* This declaration is solely to ensure that after preprocessing - this file is never empty. */ -typedef int dummy; - -#endif |