X-Git-Url: http://erislabs.net/gitweb/?a=blobdiff_plain;f=lib%2Fopenat.c;h=f2eac868d447c9829100f003345cc4d6c31ef785;hb=c8acf2dc429c96793cbb3fca726c45b6ad309944;hp=0e2c27b7b7163a079cbe9cdc962f7bb667b5c0ba;hpb=02fd4eb4561842dee666b709fbbb1632c4357d2d;p=gnulib.git diff --git a/lib/openat.c b/lib/openat.c index 0e2c27b7b..f2eac868d 100644 --- a/lib/openat.c +++ b/lib/openat.c @@ -1,5 +1,5 @@ /* provide a replacement openat function - Copyright (C) 2004-2009 Free Software Foundation, Inc. + Copyright (C) 2004-2010 Free Software Foundation, Inc. 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 @@ -22,19 +22,108 @@ #include #include +#include #include #include "dirname.h" /* solely for definition of IS_ABSOLUTE_FILE_NAME */ #include "openat-priv.h" #include "save-cwd.h" -/* We can't use "fcntl--.h", so that openat_safer does not interfere. */ -#if GNULIB_FCNTL_SAFER -# include "fcntl-safer.h" -# undef open -# define open open_safer +#if HAVE_OPENAT + +# undef openat + +/* Like openat, but work around Solaris 9 bugs with trailing slash. */ +int +rpl_openat (int dfd, char const *filename, int flags, ...) +{ + mode_t mode; + int fd; + + mode = 0; + if (flags & O_CREAT) + { + va_list arg; + va_start (arg, flags); + + /* We have to use PROMOTED_MODE_T instead of mode_t, otherwise GCC 4 + creates crashing code when 'mode_t' is smaller than 'int'. */ + mode = va_arg (arg, PROMOTED_MODE_T); + + va_end (arg); + } + +#if OPEN_TRAILING_SLASH_BUG + /* If the filename ends in a slash and one of O_CREAT, O_WRONLY, O_RDWR + is specified, then fail. + Rationale: POSIX + says that + "A pathname that contains at least one non-slash character and that + ends with one or more trailing slashes shall be resolved as if a + single dot character ( '.' ) were appended to the pathname." + and + "The special filename dot shall refer to the directory specified by + its predecessor." + If the named file already exists as a directory, then + - if O_CREAT is specified, open() must fail because of the semantics + of O_CREAT, + - if O_WRONLY or O_RDWR is specified, open() must fail because POSIX + says that it + fails with errno = EISDIR in this case. + If the named file does not exist or does not name a directory, then + - if O_CREAT is specified, open() must fail since open() cannot create + directories, + - if O_WRONLY or O_RDWR is specified, open() must fail because the + file does not contain a '.' directory. */ + if (flags & (O_CREAT | O_WRONLY | O_RDWR)) + { + size_t len = strlen (filename); + if (len > 0 && filename[len - 1] == '/') + { + errno = EISDIR; + return -1; + } + } +#endif + + fd = openat (dfd, filename, flags, mode); + +#if OPEN_TRAILING_SLASH_BUG + /* If the filename ends in a slash and fd does not refer to a directory, + then fail. + Rationale: POSIX + says that + "A pathname that contains at least one non-slash character and that + ends with one or more trailing slashes shall be resolved as if a + single dot character ( '.' ) were appended to the pathname." + and + "The special filename dot shall refer to the directory specified by + its predecessor." + If the named file without the slash is not a directory, open() must fail + with ENOTDIR. */ + if (fd >= 0) + { + /* We know len is positive, since open did not fail with ENOENT. */ + size_t len = strlen (filename); + if (filename[len - 1] == '/') + { + struct stat statbuf; + + if (fstat (fd, &statbuf) >= 0 && !S_ISDIR (statbuf.st_mode)) + { + close (fd); + errno = ENOTDIR; + return -1; + } + } + } #endif + return fd; +} + +#else /* !HAVE_OPENAT */ + /* Replacement for Solaris' openat function. First, try to simulate it via open ("/proc/self/fd/FD/FILE"). @@ -54,7 +143,7 @@ openat (int fd, char const *file, int flags, ...) va_start (arg, flags); /* We have to use PROMOTED_MODE_T instead of mode_t, otherwise GCC 4 - creates crashing code when 'mode_t' is smaller than 'int'. */ + creates crashing code when 'mode_t' is smaller than 'int'. */ mode = va_arg (arg, PROMOTED_MODE_T); va_end (arg); @@ -76,7 +165,7 @@ openat (int fd, char const *file, int flags, ...) int openat_permissive (int fd, char const *file, int flags, mode_t mode, - int *cwd_errno) + int *cwd_errno) { struct saved_cwd saved_cwd; int saved_errno; @@ -91,18 +180,18 @@ openat_permissive (int fd, char const *file, int flags, mode_t mode, char *proc_file = openat_proc_name (buf, fd, file); if (proc_file) { - int open_result = open (proc_file, flags, mode); - int open_errno = errno; - if (proc_file != buf) - free (proc_file); - /* If the syscall succeeds, or if it fails with an unexpected - errno value, then return right away. Otherwise, fall through - and resort to using save_cwd/restore_cwd. */ - if (0 <= open_result || ! EXPECTED_ERRNO (open_errno)) - { - errno = open_errno; - return open_result; - } + int open_result = open (proc_file, flags, mode); + int open_errno = errno; + if (proc_file != buf) + free (proc_file); + /* If the syscall succeeds, or if it fails with an unexpected + errno value, then return right away. Otherwise, fall through + and resort to using save_cwd/restore_cwd. */ + if (0 <= open_result || ! EXPECTED_ERRNO (open_errno)) + { + errno = open_errno; + return open_result; + } } } @@ -110,9 +199,18 @@ openat_permissive (int fd, char const *file, int flags, mode_t mode, if (! save_ok) { if (! cwd_errno) - openat_save_fail (errno); + openat_save_fail (errno); *cwd_errno = errno; } + if (0 <= fd && fd == saved_cwd.desc) + { + /* If saving the working directory collides with the user's + requested fd, then the user's fd must have been closed to + begin with. */ + free_cwd (&saved_cwd); + errno = EBADF; + return -1; + } err = fchdir (fd); saved_errno = errno; @@ -122,11 +220,17 @@ openat_permissive (int fd, char const *file, int flags, mode_t mode, err = open (file, flags, mode); saved_errno = errno; if (save_ok && restore_cwd (&saved_cwd) != 0) - { - if (! cwd_errno) - openat_restore_fail (errno); - *cwd_errno = errno; - } + { + if (! cwd_errno) + { + /* Don't write a message to just-created fd 2. */ + saved_errno = errno; + if (err == STDERR_FILENO) + close (err); + openat_restore_fail (saved_errno); + } + *cwd_errno = errno; + } } free_cwd (&saved_cwd); @@ -147,57 +251,15 @@ openat_needs_fchdir (void) char buf[OPENAT_BUFFER_SIZE]; char *proc_file = openat_proc_name (buf, fd, "."); if (proc_file) - { - needs_fchdir = false; - if (proc_file != buf) - free (proc_file); - } + { + needs_fchdir = false; + if (proc_file != buf) + free (proc_file); + } close (fd); } return needs_fchdir; } -/* Replacement for Solaris' function by the same name. - - First, try to simulate it via l?stat ("/proc/self/fd/FD/FILE"). - Failing that, simulate it via save_cwd/fchdir/(stat|lstat)/restore_cwd. - If either the save_cwd or the restore_cwd fails (relatively unlikely), - then give a diagnostic and exit nonzero. - Otherwise, this function works just like Solaris' fstatat. */ - -#define AT_FUNC_NAME fstatat -#define AT_FUNC_F1 lstat -#define AT_FUNC_F2 stat -#define AT_FUNC_USE_F1_COND flag == AT_SYMLINK_NOFOLLOW -#define AT_FUNC_POST_FILE_PARAM_DECLS , struct stat *st, int flag -#define AT_FUNC_POST_FILE_ARGS , st -#include "at-func.c" -#undef AT_FUNC_NAME -#undef AT_FUNC_F1 -#undef AT_FUNC_F2 -#undef AT_FUNC_USE_F1_COND -#undef AT_FUNC_POST_FILE_PARAM_DECLS -#undef AT_FUNC_POST_FILE_ARGS - -/* Replacement for Solaris' function by the same name. - - First, try to simulate it via (unlink|rmdir) ("/proc/self/fd/FD/FILE"). - Failing that, simulate it via save_cwd/fchdir/(unlink|rmdir)/restore_cwd. - If either the save_cwd or the restore_cwd fails (relatively unlikely), - then give a diagnostic and exit nonzero. - Otherwise, this function works just like Solaris' unlinkat. */ - -#define AT_FUNC_NAME unlinkat -#define AT_FUNC_F1 rmdir -#define AT_FUNC_F2 unlink -#define AT_FUNC_USE_F1_COND flag == AT_REMOVEDIR -#define AT_FUNC_POST_FILE_PARAM_DECLS , int flag -#define AT_FUNC_POST_FILE_ARGS /* empty */ -#include "at-func.c" -#undef AT_FUNC_NAME -#undef AT_FUNC_F1 -#undef AT_FUNC_F2 -#undef AT_FUNC_USE_F1_COND -#undef AT_FUNC_POST_FILE_PARAM_DECLS -#undef AT_FUNC_POST_FILE_ARGS +#endif /* !HAVE_OPENAT */