X-Git-Url: http://erislabs.net/gitweb/?a=blobdiff_plain;f=lib%2Fchdir-long.c;h=5b1b18fc35a180db2dfd6df0455065bea176ba09;hb=cd56634a4a8179fd5a4419fbb3e27211b042ab1c;hp=ba47d59973fd780a365bbf6bfad51f5ef61b75c3;hpb=fc333501ca97880108c8ff17e33d9dd7d5e28ed4;p=gnulib.git diff --git a/lib/chdir-long.c b/lib/chdir-long.c index ba47d5997..5b1b18fc3 100644 --- a/lib/chdir-long.c +++ b/lib/chdir-long.c @@ -1,5 +1,5 @@ /* provide a chdir function that tries not to fail due to ENAMETOOLONG - Copyright (C) 2004-2009 Free Software Foundation, Inc. + Copyright (C) 2004-2014 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 @@ -20,37 +20,41 @@ #include "chdir-long.h" +#include +#include +#include #include #include #include -#include #include -#include - -#include "fcntl--.h" #ifndef PATH_MAX # error "compile this file only if your system defines PATH_MAX" #endif +/* The results of openat() in this file are not leaked to any + single-threaded code that could use stdio. + FIXME - if the kernel ever adds support for multi-thread safety for + avoiding standard fds, then we should use openat_safer. */ + struct cd_buf { int fd; }; -static inline void +static void cdb_init (struct cd_buf *cdb) { cdb->fd = AT_FDCWD; } -static inline int +static int cdb_fchdir (struct cd_buf const *cdb) { return fchdir (cdb->fd); } -static inline void +static void cdb_free (struct cd_buf const *cdb) { if (0 <= cdb->fd) @@ -68,7 +72,7 @@ static int cdb_advance_fd (struct cd_buf *cdb, char const *dir) { int new_fd = openat (cdb->fd, dir, - O_RDONLY | O_DIRECTORY | O_NOCTTY | O_NONBLOCK); + O_SEARCH | O_DIRECTORY | O_NOCTTY | O_NONBLOCK); if (new_fd < 0) return -1; @@ -79,7 +83,7 @@ cdb_advance_fd (struct cd_buf *cdb, char const *dir) } /* Return a pointer to the first non-slash in S. */ -static inline char * +static char * _GL_ATTRIBUTE_PURE find_non_slash (char const *s) { size_t n_slash = strspn (s, "/"); @@ -92,7 +96,7 @@ find_non_slash (char const *s) name. It handles an arbitrarily long directory name by operating on manageable portions of the name. On systems without the openat syscall, this means changing the working directory to more and more - `distant' points along the long directory name and then restoring + "distant" points along the long directory name and then restoring the working directory. If any of those attempts to save or restore the working directory fails, this function exits nonzero. @@ -131,27 +135,27 @@ chdir_long (char *dir) code in the following loop cleaner. */ if (n_leading_slash == 2) { - int err; - /* Find next slash. - We already know that dir[2] is neither a slash nor '\0'. */ - char *slash = memchr (dir + 3, '/', dir_end - (dir + 3)); - if (slash == NULL) - { - errno = ENAMETOOLONG; - return -1; - } - *slash = '\0'; - err = cdb_advance_fd (&cdb, dir); - *slash = '/'; - if (err != 0) - goto Fail; - dir = find_non_slash (slash + 1); + int err; + /* Find next slash. + We already know that dir[2] is neither a slash nor '\0'. */ + char *slash = memchr (dir + 3, '/', dir_end - (dir + 3)); + if (slash == NULL) + { + errno = ENAMETOOLONG; + return -1; + } + *slash = '\0'; + err = cdb_advance_fd (&cdb, dir); + *slash = '/'; + if (err != 0) + goto Fail; + dir = find_non_slash (slash + 1); } else if (n_leading_slash) { - if (cdb_advance_fd (&cdb, "/") != 0) - goto Fail; - dir += n_leading_slash; + if (cdb_advance_fd (&cdb, "/") != 0) + goto Fail; + dir += n_leading_slash; } assert (*dir != '/'); @@ -159,31 +163,31 @@ chdir_long (char *dir) while (PATH_MAX <= dir_end - dir) { - int err; - /* Find a slash that is PATH_MAX or fewer bytes away from dir. - I.e. see if there is a slash that will give us a name of - length PATH_MAX-1 or less. */ - char *slash = memrchr (dir, '/', PATH_MAX); - if (slash == NULL) - { - errno = ENAMETOOLONG; - return -1; - } - - *slash = '\0'; - assert (slash - dir < PATH_MAX); - err = cdb_advance_fd (&cdb, dir); - *slash = '/'; - if (err != 0) - goto Fail; - - dir = find_non_slash (slash + 1); + int err; + /* Find a slash that is PATH_MAX or fewer bytes away from dir. + I.e. see if there is a slash that will give us a name of + length PATH_MAX-1 or less. */ + char *slash = memrchr (dir, '/', PATH_MAX); + if (slash == NULL) + { + errno = ENAMETOOLONG; + return -1; + } + + *slash = '\0'; + assert (slash - dir < PATH_MAX); + err = cdb_advance_fd (&cdb, dir); + *slash = '/'; + if (err != 0) + goto Fail; + + dir = find_non_slash (slash + 1); } if (dir < dir_end) { - if (cdb_advance_fd (&cdb, dir) != 0) - goto Fail; + if (cdb_advance_fd (&cdb, dir) != 0) + goto Fail; } if (cdb_fchdir (&cdb) != 0) @@ -224,10 +228,10 @@ main (int argc, char *argv[]) { int saved_errno = errno; if (feof (stdin)) - exit (0); + exit (0); error (EXIT_FAILURE, saved_errno, - "reading standard input"); + "reading standard input"); } else if (len == 0) exit (0); @@ -237,12 +241,12 @@ main (int argc, char *argv[]) if (chdir_long (line) != 0) error (EXIT_FAILURE, errno, - "chdir_long failed: %s", line); + "chdir_long failed: %s", line); if (argc <= 1) { - /* Using `pwd' here makes sense only if it is a robust implementation, - like the one in coreutils after the 2004-04-19 changes. */ + /* Using 'pwd' here makes sense only if it is a robust implementation, + like the one in coreutils after the 2004-04-19 changes. */ char const *cmd = "pwd"; execlp (cmd, (char *) NULL); error (EXIT_FAILURE, errno, "%s", cmd);