From: Florian Weimer Date: Fri, 29 Apr 2016 09:33:07 +0200 Subject: [PATCH] glob: Simplify the interface for the GLOB_ALTDIRFUNC callback gl_readdir Previously, application code had to set up the d_namlen member if the target supported it, involving conditional compilation. After this change, glob will use the length of the string in d_name instead of d_namlen to determine the file name length. All glibc targets provide the d_type and d_ino members, and setting them as needed for gl_readdir is straightforward. Changing the behavior with regards to d_ino is left to a future cleanup. --- manual/examples/mkdirent.c | 42 ++++++++++++++++++++++++++++++++++++++++++ manual/pattern.texi | 39 ++++++++++++++++++++++++++++++++++++++- posix/bug-glob2.c | 2 +- posix/glob.c | 24 +++--------------------- 4 files changed, 84 insertions(+), 23 deletions(-) create mode 100644 manual/examples/mkdirent.c diff --git a/manual/examples/mkdirent.c b/manual/examples/mkdirent.c new file mode 100644 index 000000000000..f8400f46d756 --- /dev/null +++ b/manual/examples/mkdirent.c @@ -0,0 +1,42 @@ +/* Example for creating a struct dirent object for use with glob. + Copyright (C) 2016 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 the Free Software Foundation; either version 2 + of the License, or (at your option) any later version. + + This program 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. + + You should have received a copy of the GNU General Public License + along with this program; if not, if not, see . +*/ + +#include +#include +#include +#include +#include + +struct dirent * +mkdirent (const char *name) +{ + size_t dirent_size = offsetof (struct dirent, d_name) + 1; + size_t name_length = strlen (name); + size_t total_size = dirent_size + name_length; + if (total_size < dirent_size) + { + errno = ENOMEM; + return NULL; + } + struct dirent *result = malloc (total_size); + if (result == NULL) + return NULL; + result->d_type = DT_UNKNOWN; + result->d_ino = 1; /* Do not skip this entry. */ + memcpy (result->d_name, name, name_length + 1); + return result; +} diff --git a/manual/pattern.texi b/manual/pattern.texi index d1b9275cf9c7..565e7eb6d4b4 100644 --- a/manual/pattern.texi +++ b/manual/pattern.texi @@ -237,7 +237,44 @@ function used to read the contents of a directory. It is used if the @code{GLOB_ALTDIRFUNC} bit is set in the flag parameter. The type of this field is @w{@code{struct dirent *(*) (void *)}}. -This is a GNU extension. +An implementation of @code{gl_readdir} needs to initialize the following +members of the @code{struct dirent} object: + +@table @code +@item d_type +This member should be set to the file type of the entry if it is known. +Otherwise, the value @code{DT_UNKNOWN} can be used. The @code{glob} +function may use the specified file type to avoid callbacks in cases +where the file type indicates that the data is not required. + +@item d_ino +This member needs to be non-zero, otherwise @code{glob} may skip the +current entry and call the @code{gl_readdir} callback function again to +retrieve another entry. + +@item d_name +This member must be set to the name of the entry. It must be +null-terminated. +@end table + +The example below shows how to allocate a @code{struct dirent} object +containing a given name. + +@smallexample +@include mkdirent.c.texi +@end smallexample + +The @code{glob} function reads the @code{struct dirent} members listed +above and makes a copy of the file name in the @code{d_name} member +immediately after the @code{gl_readdir} callback function returns. +Future invocations of any of the callback functions may dealloacte or +reuse the buffer. It is the responsibility of the caller of the +@code{glob} function to allocate and deallocate the buffer, around the +call to @code{glob} or using the callback functions. For example, an +application could allocate the buffer in the @code{gl_readdir} callback +function, and deallocate it in the @code{gl_closedir} callback function. + +The @code{gl_readdir} member is a GNU extension. @item gl_opendir The address of an alternative implementation of the @code{opendir} diff --git a/posix/bug-glob2.c b/posix/bug-glob2.c index ddf5ec913bcf..0fdc5d0a53c3 100644 --- a/posix/bug-glob2.c +++ b/posix/bug-glob2.c @@ -193,7 +193,7 @@ my_readdir (void *gdir) return NULL; } - dir->d.d_ino = dir->idx; + dir->d.d_ino = 1; /* glob should not skip this entry. */ #ifdef _DIRENT_HAVE_D_TYPE dir->d.d_type = filesystem[dir->idx].type; diff --git a/posix/glob.c b/posix/glob.c index 0c04c3ccfdea..9ae76ac222d2 100644 --- a/posix/glob.c +++ b/posix/glob.c @@ -57,10 +57,8 @@ #if defined HAVE_DIRENT_H || defined __GNU_LIBRARY__ # include -# define NAMLEN(dirent) strlen((dirent)->d_name) #else # define dirent direct -# define NAMLEN(dirent) (dirent)->d_namlen # ifdef HAVE_SYS_NDIR_H # include # endif @@ -76,12 +74,6 @@ #endif -/* In GNU systems, defines this macro for us. */ -#ifdef _D_NAMLEN -# undef NAMLEN -# define NAMLEN(d) _D_NAMLEN(d) -#endif - /* When used in the GNU libc the symbol _DIRENT_HAVE_D_TYPE is available if the `d_type' member for `struct dirent' is available. HAVE_STRUCT_DIRENT_D_TYPE plays the same role in GNULIB. */ @@ -105,12 +97,6 @@ /* If the system has the `struct dirent64' type we use it internally. */ #if defined _LIBC && !defined COMPILE_GLOB64 -# if defined HAVE_DIRENT_H || defined __GNU_LIBRARY__ -# define CONVERT_D_NAMLEN(d64, d32) -# else -# define CONVERT_D_NAMLEN(d64, d32) \ - (d64)->d_namlen = (d32)->d_namlen; -# endif # if (defined POSIX || defined WINDOWS32) && !defined __GNU_LIBRARY__ # define CONVERT_D_INO(d64, d32) @@ -127,8 +113,7 @@ # endif # define CONVERT_DIRENT_DIRENT64(d64, d32) \ - memcpy ((d64)->d_name, (d32)->d_name, NAMLEN (d32) + 1); \ - CONVERT_D_NAMLEN (d64, d32) \ + strcpy ((d64)->d_name, (d32)->d_name); \ CONVERT_D_INO (d64, d32) \ CONVERT_D_TYPE (d64, d32) #endif @@ -1554,7 +1539,6 @@ glob_in_dir (const char *pattern, const char *directory, int flags, while (1) { const char *name; - size_t len; #if defined _LIBC && !defined COMPILE_GLOB64 struct dirent64 *d; union @@ -1622,12 +1606,10 @@ glob_in_dir (const char *pattern, const char *directory, int flags, names = newnames; cur = 0; } - len = NAMLEN (d); - names->name[cur] = (char *) malloc (len + 1); + names->name[cur] = strdup (d->d_name); if (names->name[cur] == NULL) goto memory_error; - *((char *) mempcpy (names->name[cur++], name, len)) - = '\0'; + ++cur; ++nfound; } }