X-Git-Url: http://erislabs.net/gitweb/?a=blobdiff_plain;f=lib%2Ffchdir.c;h=36a8e358b7a1322316c56e132c6b30f65e08a367;hb=beae0bdcf7fe30f2415c16f6b8c1368d469e519c;hp=cedbcde7fe31b3ad218b1cb926c3d0649334d9fe;hpb=8fc864a0b873beea0c37acb7898a8cf5f497fb4e;p=gnulib.git diff --git a/lib/fchdir.c b/lib/fchdir.c index cedbcde7f..36a8e358b 100644 --- a/lib/fchdir.c +++ b/lib/fchdir.c @@ -1,5 +1,5 @@ /* fchdir replacement. - Copyright (C) 2006-2009 Free Software Foundation, Inc. + Copyright (C) 2006-2013 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 @@ -19,16 +19,18 @@ /* Specification. */ #include +#include #include #include #include -#include +#include #include #include #include #include -#include "canonicalize.h" +#include "dosname.h" +#include "filenamecat.h" #ifndef REPLACE_OPEN_DIRECTORY # define REPLACE_OPEN_DIRECTORY 0 @@ -42,45 +44,67 @@ descriptor, since mingw refuses to rename any in-use file system object. */ -/* Array of file descriptors opened. If it points to a directory, it stores - info about this directory; otherwise it stores an errno value of ENOTDIR. */ +/* Array of file descriptors opened. If REPLACE_OPEN_DIRECTORY or if it points + to a directory, it stores info about this directory. */ typedef struct { char *name; /* Absolute name of the directory, or NULL. */ - int saved_errno; /* If name == NULL: The error code describing the failure - reason. */ + /* FIXME - add a DIR* member to make dirfd possible on mingw? */ } dir_info_t; static dir_info_t *dirs; static size_t dirs_allocated; -/* Try to ensure dirs has enough room for a slot at index fd. */ -static void +/* Try to ensure dirs has enough room for a slot at index fd; free any + contents already in that slot. Return false and set errno to + ENOMEM on allocation failure. */ +static bool ensure_dirs_slot (size_t fd) { - if (fd >= dirs_allocated) + if (fd < dirs_allocated) + free (dirs[fd].name); + else { size_t new_allocated; dir_info_t *new_dirs; - size_t i; new_allocated = 2 * dirs_allocated + 1; if (new_allocated <= fd) - new_allocated = fd + 1; + new_allocated = fd + 1; new_dirs = - (dirs != NULL - ? (dir_info_t *) realloc (dirs, new_allocated * sizeof (dir_info_t)) - : (dir_info_t *) malloc (new_allocated * sizeof (dir_info_t))); - if (new_dirs != NULL) - { - for (i = dirs_allocated; i < new_allocated; i++) - { - new_dirs[i].name = NULL; - new_dirs[i].saved_errno = ENOTDIR; - } - dirs = new_dirs; - dirs_allocated = new_allocated; - } + (dirs != NULL + ? (dir_info_t *) realloc (dirs, new_allocated * sizeof *dirs) + : (dir_info_t *) malloc (new_allocated * sizeof *dirs)); + if (new_dirs == NULL) + return false; + memset (new_dirs + dirs_allocated, 0, + (new_allocated - dirs_allocated) * sizeof *dirs); + dirs = new_dirs; + dirs_allocated = new_allocated; } + return true; +} + +/* Return an absolute name of DIR in malloc'd storage. */ +static char * +get_name (char const *dir) +{ + char *cwd; + char *result; + int saved_errno; + + if (IS_ABSOLUTE_FILE_NAME (dir)) + return strdup (dir); + + /* We often encounter "."; treat it as a special case. */ + cwd = getcwd (NULL, 0); + if (!cwd || (dir[0] == '.' && dir[1] == '\0')) + return cwd; + + result = mfile_name_concat (cwd, dir, NULL); + saved_errno = errno; + free (cwd); + errno = saved_errno; + return result; } /* Hook into the gnulib replacements for open() and close() to keep track @@ -93,161 +117,74 @@ _gl_unregister_fd (int fd) { if (fd >= 0 && fd < dirs_allocated) { - if (dirs[fd].name != NULL) - free (dirs[fd].name); + free (dirs[fd].name); dirs[fd].name = NULL; - dirs[fd].saved_errno = ENOTDIR; } } -/* Mark FD as visiting FILENAME. FD must be positive, and refer to an - open file descriptor. If REPLACE_OPEN_DIRECTORY is non-zero, this - should only be called if FD is visiting a directory. */ -void +/* Mark FD as visiting FILENAME. FD must be non-negative, and refer + to an open file descriptor. If REPLACE_OPEN_DIRECTORY is non-zero, + this should only be called if FD is visiting a directory. Close FD + and return -1 if there is insufficient memory to track the + directory name; otherwise return FD. */ +int _gl_register_fd (int fd, const char *filename) { struct stat statbuf; - ensure_dirs_slot (fd); - if (fd < dirs_allocated - && (REPLACE_OPEN_DIRECTORY - || (fstat (fd, &statbuf) >= 0 && S_ISDIR (statbuf.st_mode)))) + assert (0 <= fd); + if (REPLACE_OPEN_DIRECTORY + || (fstat (fd, &statbuf) == 0 && S_ISDIR (statbuf.st_mode))) { - dirs[fd].name = canonicalize_file_name (filename); - if (dirs[fd].name == NULL) - dirs[fd].saved_errno = errno; + if (!ensure_dirs_slot (fd) + || (dirs[fd].name = get_name (filename)) == NULL) + { + int saved_errno = errno; + close (fd); + errno = saved_errno; + return -1; + } } + return fd; } -/* Return stat information about FD in STATBUF. Needed when - rpl_open() used a dummy file to work around an open() that can't - normally visit directories. */ -#if REPLACE_OPEN_DIRECTORY -int -rpl_fstat (int fd, struct stat *statbuf) -{ - if (0 <= fd && fd <= dirs_allocated && dirs[fd].name != NULL) - return stat (dirs[fd].name, statbuf); - return fstat (fd, statbuf); -} -#endif - -/* Override opendir() and closedir(), to keep track of the open file - descriptors. Needed because there is a function dirfd(). */ - +/* Mark NEWFD as a duplicate of OLDFD; useful from dup, dup2, dup3, + and fcntl. Both arguments must be valid and distinct file + descriptors. Close NEWFD and return -1 if OLDFD is tracking a + directory, but there is insufficient memory to track the same + directory in NEWFD; otherwise return NEWFD. */ int -rpl_closedir (DIR *dp) -#undef closedir -{ - int fd = dirfd (dp); - int retval = closedir (dp); - - if (retval >= 0) - _gl_unregister_fd (fd); - return retval; -} - -DIR * -rpl_opendir (const char *filename) -#undef opendir +_gl_register_dup (int oldfd, int newfd) { - DIR *dp; - - dp = opendir (filename); - if (dp != NULL) + assert (0 <= oldfd && 0 <= newfd && oldfd != newfd); + if (oldfd < dirs_allocated && dirs[oldfd].name) { - int fd = dirfd (dp); - if (fd >= 0) - _gl_register_fd (fd, filename); + /* Duplicated a directory; must ensure newfd is allocated. */ + if (!ensure_dirs_slot (newfd) + || (dirs[newfd].name = strdup (dirs[oldfd].name)) == NULL) + { + int saved_errno = errno; + close (newfd); + errno = saved_errno; + newfd = -1; + } } - return dp; -} - -/* Override dup() and dup2(), to keep track of open file descriptors. */ - -int -rpl_dup (int oldfd) -#undef dup -{ - int newfd = dup (oldfd); - - if (oldfd >= 0 && newfd >= 0) + else if (newfd < dirs_allocated) { - ensure_dirs_slot (newfd); - if (newfd < dirs_allocated) - { - if (oldfd < dirs_allocated) - { - if (dirs[oldfd].name != NULL) - { - dirs[newfd].name = strdup (dirs[oldfd].name); - if (dirs[newfd].name == NULL) - dirs[newfd].saved_errno = ENOMEM; - } - else - { - dirs[newfd].name = NULL; - dirs[newfd].saved_errno = dirs[oldfd].saved_errno; - } - } - else - { - dirs[newfd].name = NULL; - dirs[newfd].saved_errno = ENOMEM; - } - } + /* Duplicated a non-directory; ensure newfd is cleared. */ + free (dirs[newfd].name); + dirs[newfd].name = NULL; } return newfd; } -/* Our replacement overrides dup2 twice; be sure to pick - the one we want. */ -#if REPLACE_DUP2 -# undef dup2 -# define dup2 rpl_dup2 -#endif - -int -rpl_dup2_fchdir (int oldfd, int newfd) -{ - int retval = dup2 (oldfd, newfd); - - if (retval >= 0 && newfd != oldfd) - { - ensure_dirs_slot (newfd); - if (newfd < dirs_allocated) - { - if (oldfd < dirs_allocated) - { - if (dirs[oldfd].name != NULL) - { - dirs[newfd].name = strdup (dirs[oldfd].name); - if (dirs[newfd].name == NULL) - dirs[newfd].saved_errno = ENOMEM; - } - else - { - dirs[newfd].name = NULL; - dirs[newfd].saved_errno = dirs[oldfd].saved_errno; - } - } - else - { - dirs[newfd].name = NULL; - dirs[newfd].saved_errno = ENOMEM; - } - } - } - return retval; -} - -/* Implement fchdir() in terms of chdir(). */ - -int -fchdir (int fd) +/* If FD is currently visiting a directory, then return the name of + that directory. Otherwise, return NULL and set errno. */ +const char * +_gl_directory_name (int fd) { - if (fd >= 0 && fd < dirs_allocated && dirs[fd].name != NULL) - return chdir (dirs[fd].name); + if (0 <= fd && fd < dirs_allocated && dirs[fd].name != NULL) + return dirs[fd].name; /* At this point, fd is either invalid, or open but not a directory. If dup2 fails, errno is correctly EBADF. */ if (0 <= fd) @@ -257,5 +194,15 @@ fchdir (int fd) } else errno = EBADF; - return -1; + return NULL; +} + + +/* Implement fchdir() in terms of chdir(). */ + +int +fchdir (int fd) +{ + const char *name = _gl_directory_name (fd); + return name ? chdir (name) : -1; }