X-Git-Url: https://git.gag.com/?a=blobdiff_plain;f=lib%2Fopenat-proc.c;fp=lib%2Fopenat-proc.c;h=1712340a00274ccb976a3c3a996475207be9124c;hb=20fcfc81ece044b8b0a6768ec6cf47be4e22a2e6;hp=d7a68e26d0b4dc185d48d614a4c19e403faa98a1;hpb=d57728a6ca2413a7c564d8b7bb13d9e5a5a180f3;p=debian%2Fgzip diff --git a/lib/openat-proc.c b/lib/openat-proc.c index d7a68e2..1712340 100644 --- a/lib/openat-proc.c +++ b/lib/openat-proc.c @@ -1,6 +1,6 @@ /* Create /proc/self/fd-related names for subfiles of open directories. - Copyright (C) 2006, 2009-2013 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 it under the terms of the GNU General Public License as published by @@ -30,32 +30,21 @@ #include #include -#include "intprops.h" - -/* The results of open() in this file are not used with fchdir, - and we do not leak fds to any single-threaded code that could use stdio, - therefore save some unnecessary work in fchdir.c. - FIXME - if the kernel ever adds support for multi-thread safety for - avoiding standard fds, then we should use open_safer. */ -#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 +#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, either because the operating - system support is lacking or because memory is low. */ +/* 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; /* Make sure the caller gets ENOENT when appropriate. */ if (!*file) @@ -64,47 +53,82 @@ openat_proc_name (char buf[OPENAT_BUFFER_SIZE], int fd, char const *file) return buf; } - 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_NAME_SIZE_BOUND (sizeof "../fd" - 1)]; - sprintf (dotdot_buf, PROC_SELF_FD_FORMAT, proc_self_fd, "../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_NAME_SIZE_BOUND (strlen (file)); - char *result = buf; - if (OPENAT_BUFFER_SIZE < bufsize) - { - result = malloc (bufsize); - if (! result) - return NULL; - } - 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; }