From 27b0767593284f97384b3597ebd211164f8c8b47 Mon Sep 17 00:00:00 2001 From: Alan Modra Date: Tue, 5 Jun 2018 21:04:00 +0930 Subject: PR23254, ld.bfd mishandles file pointers while scanning archive Best practice is to not mix lseek/read with fseek/fread on the same underlying file descriptor, as not all stdio implementations will cope. Since the plugin uses lseek/read while bfd uses fseek/fread this patch reopens the file for exclusive use by the plugin rather than trying to restore the file descriptor. That allows the plugin to read the file after plugin_call_claim_file too. bfd/ PR 23254 * plugin.c (bfd_plugin_open_input): Allow for possibility of nested archives. Open file again for plugin. (try_claim): Don't save and restore file position. Close file if not claimed. * sysdep.h (O_BINARY): Define. ld/ PR 23254 * plugin.c (plugin_call_claim_file): Revert 2016-07-19 patch. (plugin_object_p): Don't dup file descriptor. --- bfd/plugin.c | 20 ++++++++++++++------ 1 file changed, 14 insertions(+), 6 deletions(-) (limited to 'bfd/plugin.c') diff --git a/bfd/plugin.c b/bfd/plugin.c index 16a706a..7c5bba2 100644 --- a/bfd/plugin.c +++ b/bfd/plugin.c @@ -166,14 +166,22 @@ bfd_plugin_open_input (bfd *ibfd, struct ld_plugin_input_file *file) bfd *iobfd; iobfd = ibfd; - if (ibfd->my_archive && !bfd_is_thin_archive (ibfd->my_archive)) - iobfd = ibfd->my_archive; + while (iobfd->my_archive + && !bfd_is_thin_archive (iobfd->my_archive)) + iobfd = iobfd->my_archive; file->name = iobfd->filename; if (!iobfd->iostream && !bfd_open_file (iobfd)) return 0; - file->fd = fileno ((FILE *) iobfd->iostream); + /* The plugin API expects that the file descriptor won't be closed + and reused as done by the bfd file cache. So open it again. + dup isn't good enough. plugin IO uses lseek/read while BFD uses + fseek/fread. It isn't wise to mix the unistd and stdio calls on + the same underlying file descriptor. */ + file->fd = open (file->name, O_RDONLY | O_BINARY); + if (file->fd < 0) + return 0; if (iobfd == ibfd) { @@ -197,12 +205,12 @@ try_claim (bfd *abfd) int claimed = 0; struct ld_plugin_input_file file; + file.handle = abfd; if (!bfd_plugin_open_input (abfd, &file)) return 0; - file.handle = abfd; - off_t cur_offset = lseek (file.fd, 0, SEEK_CUR); claim_file (&file, &claimed); - lseek (file.fd, cur_offset, SEEK_SET); + if (!claimed) + close (file.fd); return claimed; } -- cgit v1.1