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https://github.com/freebsd/freebsd-src
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3610bffd28
Right now pkill/pgrep cut off at _POSIX2_LINE_MAX (2048), but argument strings can be much larger (ARG_MAX is 256K/512K). Stop arbitrarily cutting the search off at 2K, rather than documenting the limit. Reviewed by: allanjude (earlier version), des Sponsored by: Klara, Inc. Differential Revision: https://reviews.freebsd.org/D38663
124 lines
3.2 KiB
C
124 lines
3.2 KiB
C
/*-
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* SPDX-License-Identifier: BSD-2-Clause
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*
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* Copyright (c) 2023 Klara, Inc.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#include <sys/cdefs.h>
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#include <err.h>
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#include <errno.h>
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#include <fcntl.h>
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#include <limits.h>
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#include <stdlib.h>
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#include <string.h>
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#include <stdio.h>
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#include <unistd.h>
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static int
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exec_shortargs(char *argv[])
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{
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char *flag_arg = argv[2];
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char *sentinel = argv[3];
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char * nargv[] = { argv[0], __DECONST(char *, "--spin"), flag_arg,
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sentinel, NULL };
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char * const nenvp[] = { NULL };
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execve(argv[0], nargv, nenvp);
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err(1, "execve");
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}
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static int
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exec_largeargs(char *argv[])
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{
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char *flag_arg = argv[2];
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char *sentinel = argv[3];
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/*
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* Account for each argument and their NUL terminator, as well as an
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* extra NUL terminator.
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*/
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size_t bufsz = ARG_MAX -
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((strlen(argv[0]) + 1) + sizeof("--spin") + (strlen(flag_arg) + 1) +
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(strlen(sentinel) + 1) + 1);
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char *s = NULL;
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char * nargv[] = { argv[0], __DECONST(char *, "--spin"), flag_arg, NULL,
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sentinel, NULL };
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char * const nenvp[] = { NULL };
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/*
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* Our heuristic may or may not be accurate, we'll keep trying with
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* smaller argument sizes as needed until we stop getting E2BIG.
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*/
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do {
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if (s == NULL)
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s = malloc(bufsz + 1);
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else
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s = realloc(s, bufsz + 1);
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if (s == NULL)
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abort();
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memset(s, 'x', bufsz);
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s[bufsz] = '\0';
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nargv[3] = s;
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execve(argv[0], nargv, nenvp);
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bufsz--;
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} while (errno == E2BIG);
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err(1, "execve");
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}
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int
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main(int argc, char *argv[])
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{
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if (argc > 1 && strcmp(argv[1], "--spin") == 0) {
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int fd;
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if (argc < 4) {
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fprintf(stderr, "usage: %s --spin flagfile ...\n", argv[0]);
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return (1);
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}
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fd = open(argv[2], O_RDWR | O_CREAT, 0755);
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if (fd < 0)
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err(1, "%s", argv[2]);
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close(fd);
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for (;;) {
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sleep(1);
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}
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return (1);
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}
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if (argc != 4) {
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fprintf(stderr, "usage: %s [--short | --long] flagfile sentinel\n",
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argv[0]);
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return (1);
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}
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if (strcmp(argv[1], "--short") == 0)
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exec_shortargs(argv);
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else
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exec_largeargs(argv);
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}
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