forward.c revision 72102e7461c97dc268d21d9dd8f02da45f174acd
209e49b2ff611e7d61ff58e13756ae67f51be550Chris Love * Copyright (c) 1991, 1993
209e49b2ff611e7d61ff58e13756ae67f51be550Chris Love * The Regents of the University of California. All rights reserved.
209e49b2ff611e7d61ff58e13756ae67f51be550Chris Love * This code is derived from software contributed to Berkeley by
209e49b2ff611e7d61ff58e13756ae67f51be550Chris Love * Edward Sze-Tyan Wang.
209e49b2ff611e7d61ff58e13756ae67f51be550Chris Love * Redistribution and use in source and binary forms, with or without
209e49b2ff611e7d61ff58e13756ae67f51be550Chris Love * modification, are permitted provided that the following conditions
209e49b2ff611e7d61ff58e13756ae67f51be550Chris Love * 1. Redistributions of source code must retain the above copyright
209e49b2ff611e7d61ff58e13756ae67f51be550Chris Love * notice, this list of conditions and the following disclaimer.
209e49b2ff611e7d61ff58e13756ae67f51be550Chris Love * 2. Redistributions in binary form must reproduce the above copyright
209e49b2ff611e7d61ff58e13756ae67f51be550Chris Love * notice, this list of conditions and the following disclaimer in the
209e49b2ff611e7d61ff58e13756ae67f51be550Chris Love * documentation and/or other materials provided with the distribution.
209e49b2ff611e7d61ff58e13756ae67f51be550Chris Love * 4. Neither the name of the University nor the names of its contributors
209e49b2ff611e7d61ff58e13756ae67f51be550Chris Love * may be used to endorse or promote products derived from this software
209e49b2ff611e7d61ff58e13756ae67f51be550Chris Love * without specific prior written permission.
209e49b2ff611e7d61ff58e13756ae67f51be550Chris Love * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
209e49b2ff611e7d61ff58e13756ae67f51be550Chris Love * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
209e49b2ff611e7d61ff58e13756ae67f51be550Chris Love * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
209e49b2ff611e7d61ff58e13756ae67f51be550Chris Love * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
209e49b2ff611e7d61ff58e13756ae67f51be550Chris Love * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
209e49b2ff611e7d61ff58e13756ae67f51be550Chris Love * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
209e49b2ff611e7d61ff58e13756ae67f51be550Chris Love * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
209e49b2ff611e7d61ff58e13756ae67f51be550Chris Love * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
209e49b2ff611e7d61ff58e13756ae67f51be550Chris Love * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
209e49b2ff611e7d61ff58e13756ae67f51be550Chris Love * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
209e49b2ff611e7d61ff58e13756ae67f51be550Chris Love * SUCH DAMAGE.
72102e7461c97dc268d21d9dd8f02da45f174acdBryan Cantrill * Copyright (c) 2013, Joyent, Inc. All rights reserved.
209e49b2ff611e7d61ff58e13756ae67f51be550Chris Lovestatic void rlines(FILE *, const char *fn, off_t, struct stat *);
209e49b2ff611e7d61ff58e13756ae67f51be550Chris Love/* defines for inner loop actions */
209e49b2ff611e7d61ff58e13756ae67f51be550Chris Love * forward -- display the file, from an offset, forward.
209e49b2ff611e7d61ff58e13756ae67f51be550Chris Love * There are eight separate cases for this -- regular and non-regular
209e49b2ff611e7d61ff58e13756ae67f51be550Chris Love * files, by bytes or lines and from the beginning or end of the file.
209e49b2ff611e7d61ff58e13756ae67f51be550Chris Love * FBYTES byte offset from the beginning of the file
209e49b2ff611e7d61ff58e13756ae67f51be550Chris Love * NOREG read, counting bytes
209e49b2ff611e7d61ff58e13756ae67f51be550Chris Love * FLINES line offset from the beginning of the file
209e49b2ff611e7d61ff58e13756ae67f51be550Chris Love * REG read, counting lines
209e49b2ff611e7d61ff58e13756ae67f51be550Chris Love * NOREG read, counting lines
209e49b2ff611e7d61ff58e13756ae67f51be550Chris Love * RBYTES byte offset from the end of the file
209e49b2ff611e7d61ff58e13756ae67f51be550Chris Love * NOREG cyclically read characters into a wrap-around buffer
209e49b2ff611e7d61ff58e13756ae67f51be550Chris Love * REG mmap the file and step back until reach the correct offset.
209e49b2ff611e7d61ff58e13756ae67f51be550Chris Love * NOREG cyclically read lines into a wrap-around array of buffers
209e49b2ff611e7d61ff58e13756ae67f51be550Chris Loveforward(FILE *fp, const char *fn, enum STYLE style, off_t off, struct stat *sbp)
209e49b2ff611e7d61ff58e13756ae67f51be550Chris Love } else while (off--)
209e49b2ff611e7d61ff58e13756ae67f51be550Chris Love } else if (off == 0) {
209e49b2ff611e7d61ff58e13756ae67f51be550Chris Love else if (off == 0) {
209e49b2ff611e7d61ff58e13756ae67f51be550Chris Love * rlines -- display the last offset lines of the file.
209e49b2ff611e7d61ff58e13756ae67f51be550Chris Loverlines(FILE *fp, const char *fn, off_t off, struct stat *sbp)
209e49b2ff611e7d61ff58e13756ae67f51be550Chris Love * Last char is special, ignore whether newline or not. Note that
209e49b2ff611e7d61ff58e13756ae67f51be550Chris Love * size == 0 is dealt with above, and size == 1 sets curoff to -1.
209e49b2ff611e7d61ff58e13756ae67f51be550Chris Love while (curoff >= 0) {
209e49b2ff611e7d61ff58e13756ae67f51be550Chris Love if (curoff < map.mapoff && maparound(&map, curoff) != 0) {
209e49b2ff611e7d61ff58e13756ae67f51be550Chris Love /* `i' is either the map offset of a '\n', or -1. */
209e49b2ff611e7d61ff58e13756ae67f51be550Chris Love if (mapprint(&map, curoff, size - curoff) != 0) {
209e49b2ff611e7d61ff58e13756ae67f51be550Chris Love /* Set the file pointer to reflect the length displayed. */
209e49b2ff611e7d61ff58e13756ae67f51be550Chris Love if (map.start != NULL && munmap(map.start, map.maplen)) {
72102e7461c97dc268d21d9dd8f02da45f174acdBryan Cantrillassociate(file_info_t *file, boolean_t assoc, port_event_t *ev)
72102e7461c97dc268d21d9dd8f02da45f174acdBryan Cantrill * For FIFOs, we use PORT_SOURCE_FD as our port event source.
72102e7461c97dc268d21d9dd8f02da45f174acdBryan Cantrill * PORT_SOURCE_FILE only allows us to specify a file name, not
72102e7461c97dc268d21d9dd8f02da45f174acdBryan Cantrill * a file descriptor. If we are following a specific file (as
72102e7461c97dc268d21d9dd8f02da45f174acdBryan Cantrill * opposed to a file name) and we were to specify the name of
72102e7461c97dc268d21d9dd8f02da45f174acdBryan Cantrill * the file to port_associate() and that file were moved
72102e7461c97dc268d21d9dd8f02da45f174acdBryan Cantrill * aside, we would not be able to reassociate an event because
72102e7461c97dc268d21d9dd8f02da45f174acdBryan Cantrill * we would not know a name that would resolve to the new file
72102e7461c97dc268d21d9dd8f02da45f174acdBryan Cantrill * (indeed, there might not be such a name -- the file may
72102e7461c97dc268d21d9dd8f02da45f174acdBryan Cantrill * have been unlinked). But there _is_ a name that we know
72102e7461c97dc268d21d9dd8f02da45f174acdBryan Cantrill * maps to the file and doesn't change: the name of the
72102e7461c97dc268d21d9dd8f02da45f174acdBryan Cantrill * representation of the open file descriptor in /proc. We
72102e7461c97dc268d21d9dd8f02da45f174acdBryan Cantrill * therefore associate with this name (and the underlying
72102e7461c97dc268d21d9dd8f02da45f174acdBryan Cantrill * file), not the name of the file as specified at the command
72102e7461c97dc268d21d9dd8f02da45f174acdBryan Cantrill * line. This also has the (desirable) side-effect of
72102e7461c97dc268d21d9dd8f02da45f174acdBryan Cantrill * insulating against FILE_RENAME_FROM and FILE_RENAME_TO
72102e7461c97dc268d21d9dd8f02da45f174acdBryan Cantrill * events that we need to ignore to assure that we don't lose
72102e7461c97dc268d21d9dd8f02da45f174acdBryan Cantrill * FILE_TRUNC events.
72102e7461c97dc268d21d9dd8f02da45f174acdBryan Cantrill sizeof (buf), "/proc/self/fd/%d", fileno(file->fp));
72102e7461c97dc268d21d9dd8f02da45f174acdBryan Cantrill * Note that portfs uses the address of the specified file_obj_t to
72102e7461c97dc268d21d9dd8f02da45f174acdBryan Cantrill * tag an association; if one creates a different association with a
72102e7461c97dc268d21d9dd8f02da45f174acdBryan Cantrill * (different) file_obj_t that happens to be at the same address,
72102e7461c97dc268d21d9dd8f02da45f174acdBryan Cantrill * the first association will be implicitly removed. To assure that
72102e7461c97dc268d21d9dd8f02da45f174acdBryan Cantrill * each association has a disjoint file_obj_t, we allocate the memory
72102e7461c97dc268d21d9dd8f02da45f174acdBryan Cantrill * for each in the file_info, not on the stack.
72102e7461c97dc268d21d9dd8f02da45f174acdBryan Cantrill * To assure that we cannot possibly drop a FILE_TRUNC event,
72102e7461c97dc268d21d9dd8f02da45f174acdBryan Cantrill * we have two different PORT_SOURCE_FILE associations with the
72102e7461c97dc268d21d9dd8f02da45f174acdBryan Cantrill * port: one to get only FILE_MODIFIED events and another to
72102e7461c97dc268d21d9dd8f02da45f174acdBryan Cantrill * get only FILE_TRUNC events. This assures that we always
72102e7461c97dc268d21d9dd8f02da45f174acdBryan Cantrill * have an active association for FILE_TRUNC events when the
72102e7461c97dc268d21d9dd8f02da45f174acdBryan Cantrill * seek offset is non-zero. Note that the association order
72102e7461c97dc268d21d9dd8f02da45f174acdBryan Cantrill * _must_ be FILE_TRUNC followed by FILE_MODIFIED: if a single
72102e7461c97dc268d21d9dd8f02da45f174acdBryan Cantrill * event induces both a FILE_TRUNC and a FILE_MODIFIED (as
72102e7461c97dc268d21d9dd8f02da45f174acdBryan Cantrill * a VE_CREATE vnode event does), we must process the
72102e7461c97dc268d21d9dd8f02da45f174acdBryan Cantrill * FILE_TRUNC before FILE_MODIFIED -- and the order in which
72102e7461c97dc268d21d9dd8f02da45f174acdBryan Cantrill * these are processed will be the association order. So
72102e7461c97dc268d21d9dd8f02da45f174acdBryan Cantrill * if we see a FILE_TRUNC, we dissociate/reassociate the
72102e7461c97dc268d21d9dd8f02da45f174acdBryan Cantrill * FILE_MODIFIED association.
72102e7461c97dc268d21d9dd8f02da45f174acdBryan Cantrill if (ev == NULL || (ev->portev_events & FILE_TRUNC) ||
72102e7461c97dc268d21d9dd8f02da45f174acdBryan Cantrill !(ev->portev_events & (FILE_MODIFIED | FILE_TRUNC))) {
72102e7461c97dc268d21d9dd8f02da45f174acdBryan Cantrill (void) port_associate(port, PORT_SOURCE_FILE,
72102e7461c97dc268d21d9dd8f02da45f174acdBryan Cantrill (uintptr_t)&file->fobj[0], FILE_TRUNC, file);
72102e7461c97dc268d21d9dd8f02da45f174acdBryan Cantrill (void) port_dissociate(port, PORT_SOURCE_FILE,
72102e7461c97dc268d21d9dd8f02da45f174acdBryan Cantrill if (ev == NULL || (ev->portev_events & FILE_MODIFIED) ||
72102e7461c97dc268d21d9dd8f02da45f174acdBryan Cantrill !(ev->portev_events & (FILE_MODIFIED | FILE_TRUNC))) {
72102e7461c97dc268d21d9dd8f02da45f174acdBryan Cantrill (void) port_associate(port, PORT_SOURCE_FILE,
72102e7461c97dc268d21d9dd8f02da45f174acdBryan Cantrill (uintptr_t)&file->fobj[1], FILE_MODIFIED, file);
72102e7461c97dc268d21d9dd8f02da45f174acdBryan Cantrill for (i = 0; i <= 1; i++) {
72102e7461c97dc268d21d9dd8f02da45f174acdBryan Cantrill (void) port_dissociate(port, PORT_SOURCE_FILE,
209e49b2ff611e7d61ff58e13756ae67f51be550Chris Love for (i = 0, file = files; i < no_files; i++, file++) {
209e49b2ff611e7d61ff58e13756ae67f51be550Chris Love * follow -- display the file, from an offset, forward.
209e49b2ff611e7d61ff58e13756ae67f51be550Chris Lovefollow(file_info_t *files, enum STYLE style, off_t off)
209e49b2ff611e7d61ff58e13756ae67f51be550Chris Love /* Position each of the files */
72102e7461c97dc268d21d9dd8f02da45f174acdBryan Cantrill (stat("/proc/self/fd", &sb2) == -1 || !S_ISDIR(sb2.st_mode) ||
209e49b2ff611e7d61ff58e13756ae67f51be550Chris Love for (i = 0, file = files; i < no_files; i++, file++) {
209e49b2ff611e7d61ff58e13756ae67f51be550Chris Love sizeof (struct stat));
209e49b2ff611e7d61ff58e13756ae67f51be550Chris Love for (i = 0, file = files; i < no_files; i++, file++)
72102e7461c97dc268d21d9dd8f02da45f174acdBryan Cantrill * In the -F case we set a timeout to ensure that
72102e7461c97dc268d21d9dd8f02da45f174acdBryan Cantrill * we re-stat the file at least once every second.
72102e7461c97dc268d21d9dd8f02da45f174acdBryan Cantrill if (n == 0) {