diff options
Diffstat (limited to 'lib/openat-proc.c')
| -rw-r--r-- | lib/openat-proc.c | 159 |
1 files changed, 99 insertions, 60 deletions
diff --git a/lib/openat-proc.c b/lib/openat-proc.c index ff2fff0..6fba6c2 100644 --- a/lib/openat-proc.c +++ b/lib/openat-proc.c @@ -1,11 +1,11 @@ /* Create /proc/self/fd-related names for subfiles of open directories. - Copyright (C) 2006 Free Software Foundation, Inc. + Copyright (C) 2006, 2009-2016 Free Software Foundation, Inc. - This program is free software; you can redistribute it and/or modify + 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, or (at your option) - any later version. + 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, but WITHOUT ANY WARRANTY; without even the implied warranty of @@ -13,8 +13,7 @@ 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, write to the Free Software Foundation, - Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */ + along with this program. If not, see <http://www.gnu.org/licenses/>. */ /* Written by Paul Eggert. */ @@ -27,69 +26,109 @@ #include <fcntl.h> #include <stdio.h> +#include <stdlib.h> #include <string.h> +#include <unistd.h> -#include "dirname.h" -#include "intprops.h" -#include "same-inode.h" -#include "xalloc.h" - -/* The results of open() in this file are not used with fchdir, - therefore save some unnecessary work in fchdir.c. */ -#undef open -#undef close - -#define PROC_SELF_FD_FORMAT "/proc/self/fd/%d/%s" - -#define PROC_SELF_FD_NAME_SIZE_BOUND(len) \ - (sizeof PROC_SELF_FD_FORMAT - sizeof "%d%s" \ - + INT_STRLEN_BOUND (int) + (len) + 1) +#ifdef __KLIBC__ +# include <InnoTekLIBC/backend.h> +#endif +#include "intprops.h" -/* Set BUF to the expansion of PROC_SELF_FD_FORMAT, using FD and FILE - respectively for %d and %s. If successful, return BUF if the - result fits in BUF, dynamically allocated memory otherwise. But - return NULL if /proc is not reliable. */ +/* Set BUF to the name of the subfile of the directory identified by + FD, where the subfile is named FILE. If successful, return BUF if + the result fits in BUF, dynamically allocated memory otherwise. + Return NULL (setting errno) on error. */ char * openat_proc_name (char buf[OPENAT_BUFFER_SIZE], int fd, char const *file) { - static int proc_status = 0; + char *result = buf; + int dirlen; - if (! proc_status) + /* Make sure the caller gets ENOENT when appropriate. */ + if (!*file) { - /* Set PROC_STATUS to a positive value if /proc/self/fd is - reliable, and a negative value otherwise. Solaris 10 - /proc/self/fd mishandles "..", and any file name might expand - to ".." after symbolic link expansion, so avoid /proc/self/fd - if it mishandles "..". Solaris 10 has openat, but this - problem is exhibited on code that built on Solaris 8 and - running on Solaris 10. */ - - int proc_self_fd = open ("/proc/self/fd", O_RDONLY); - if (proc_self_fd < 0) - proc_status = -1; - else - { - struct stat proc_self_fd_dotdot_st; - struct stat proc_self_st; - char dotdot_buf[PROC_SELF_FD_NAME_SIZE_BOUND (sizeof ".." - 1)]; - sprintf (dotdot_buf, PROC_SELF_FD_FORMAT, proc_self_fd, ".."); - proc_status = - ((stat (dotdot_buf, &proc_self_fd_dotdot_st) == 0 - && stat ("/proc/self", &proc_self_st) == 0 - && SAME_INODE (proc_self_fd_dotdot_st, proc_self_st)) - ? 1 : -1); - close (proc_self_fd); - } + buf[0] = '\0'; + return buf; } - if (proc_status < 0) - return NULL; - else - { - size_t bufsize = PROC_SELF_FD_NAME_SIZE_BOUND (strlen (file)); - char *result = (bufsize < OPENAT_BUFFER_SIZE ? buf : xmalloc (bufsize)); - sprintf (result, PROC_SELF_FD_FORMAT, fd, file); - return result; - } +#ifndef __KLIBC__ +# define PROC_SELF_FD_FORMAT "/proc/self/fd/%d/" + { + enum { + PROC_SELF_FD_DIR_SIZE_BOUND + = (sizeof PROC_SELF_FD_FORMAT - (sizeof "%d" - 1) + + INT_STRLEN_BOUND (int)) + }; + + static int proc_status = 0; + if (! proc_status) + { + /* Set PROC_STATUS to a positive value if /proc/self/fd is + reliable, and a negative value otherwise. Solaris 10 + /proc/self/fd mishandles "..", and any file name might expand + to ".." after symbolic link expansion, so avoid /proc/self/fd + if it mishandles "..". Solaris 10 has openat, but this + problem is exhibited on code that built on Solaris 8 and + running on Solaris 10. */ + + int proc_self_fd = open ("/proc/self/fd", + O_SEARCH | O_DIRECTORY | O_NOCTTY | O_NONBLOCK); + if (proc_self_fd < 0) + proc_status = -1; + else + { + /* Detect whether /proc/self/fd/%i/../fd exists, where %i is the + number of a file descriptor open on /proc/self/fd. On Linux, + that name resolves to /proc/self/fd, which was opened above. + However, on Solaris, it may resolve to /proc/self/fd/fd, which + cannot exist, since all names in /proc/self/fd are numeric. */ + char dotdot_buf[PROC_SELF_FD_DIR_SIZE_BOUND + sizeof "../fd" - 1]; + sprintf (dotdot_buf, PROC_SELF_FD_FORMAT "../fd", proc_self_fd); + proc_status = access (dotdot_buf, F_OK) ? -1 : 1; + close (proc_self_fd); + } + } + + if (proc_status < 0) + return NULL; + else + { + size_t bufsize = PROC_SELF_FD_DIR_SIZE_BOUND + strlen (file); + if (OPENAT_BUFFER_SIZE < bufsize) + { + result = malloc (bufsize); + if (! result) + return NULL; + } + + dirlen = sprintf (result, PROC_SELF_FD_FORMAT, fd); + } + } +#else + /* OS/2 kLIBC provides a function to retrieve a path from a fd. */ + { + char dir[_MAX_PATH]; + size_t bufsize; + + if (__libc_Back_ioFHToPath (fd, dir, sizeof dir)) + return NULL; + + dirlen = strlen (dir); + bufsize = dirlen + 1 + strlen (file) + 1; /* 1 for '/', 1 for null */ + if (OPENAT_BUFFER_SIZE < bufsize) + { + result = malloc (bufsize); + if (! result) + return NULL; + } + + strcpy (result, dir); + result[dirlen] = '/'; + } +#endif + + strcpy (result + dirlen, file); + return result; } |