diff options
Diffstat (limited to 'usr.bin/cmp/regular.c')
| -rw-r--r-- | usr.bin/cmp/regular.c | 191 |
1 files changed, 191 insertions, 0 deletions
diff --git a/usr.bin/cmp/regular.c b/usr.bin/cmp/regular.c new file mode 100644 index 000000000000..c4407f708e8a --- /dev/null +++ b/usr.bin/cmp/regular.c @@ -0,0 +1,191 @@ +/*- + * SPDX-License-Identifier: BSD-3-Clause + * + * Copyright (c) 1991, 1993, 1994 + * The Regents of the University of California. All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * 3. Neither the name of the University nor the names of its contributors + * may be used to endorse or promote products derived from this software + * without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND + * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE + * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL + * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS + * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY + * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF + * SUCH DAMAGE. + */ + +#include <sys/param.h> +#include <sys/mman.h> +#include <sys/stat.h> + +#include <capsicum_helpers.h> +#include <err.h> +#include <limits.h> +#include <signal.h> +#include <stdbool.h> +#include <stdlib.h> +#include <stdio.h> +#include <unistd.h> + +#include "extern.h" + +static u_char *remmap(u_char *, int, off_t); +static void segv_handler(int); +#define MMAP_CHUNK (8*1024*1024) + +#define ROUNDPAGE(i) ((i) & ~pagemask) + +int +c_regular(int fd1, const char *file1, off_t skip1, off_t len1, + int fd2, const char *file2, off_t skip2, off_t len2, off_t limit) +{ + struct sigaction act, oact; + cap_rights_t rights; + u_char ch, *p1, *p2, *m1, *m2, *e1, *e2; + off_t byte, length, line; + off_t pagemask, off1, off2; + size_t pagesize; + int dfound; + + if (skip1 > len1) { + eofmsg(file1); + return (DIFF_EXIT); + } + len1 -= skip1; + if (skip2 > len2) { + eofmsg(file2); + return (DIFF_EXIT); + } + len2 -= skip2; + + if (sflag && len1 != len2) + return (DIFF_EXIT); + + pagesize = getpagesize(); + pagemask = (off_t)pagesize - 1; + off1 = ROUNDPAGE(skip1); + off2 = ROUNDPAGE(skip2); + + length = MIN(len1, len2); + if (limit > 0) + length = MIN(length, limit); + + if ((m1 = remmap(NULL, fd1, off1)) == NULL) { + return (c_special(fd1, file1, skip1, fd2, file2, skip2, limit)); + } + + if ((m2 = remmap(NULL, fd2, off2)) == NULL) { + munmap(m1, MMAP_CHUNK); + return (c_special(fd1, file1, skip1, fd2, file2, skip2, limit)); + } + + if (caph_rights_limit(fd1, cap_rights_init(&rights, CAP_MMAP_R)) < 0) + err(1, "unable to limit rights for %s", file1); + if (caph_rights_limit(fd2, cap_rights_init(&rights, CAP_MMAP_R)) < 0) + err(1, "unable to limit rights for %s", file2); + if (caph_enter() < 0) + err(ERR_EXIT, "unable to enter capability mode"); + + sigemptyset(&act.sa_mask); + act.sa_flags = SA_NODEFER; + act.sa_handler = segv_handler; + if (sigaction(SIGSEGV, &act, &oact)) + err(ERR_EXIT, "sigaction()"); + + dfound = 0; + e1 = m1 + MMAP_CHUNK; + e2 = m2 + MMAP_CHUNK; + p1 = m1 + (skip1 - off1); + p2 = m2 + (skip2 - off2); + + for (byte = line = 1; length--; ++byte) { +#ifdef SIGINFO + if (info) { + (void)fprintf(stderr, "%s %s char %zu line %zu\n", + file1, file2, (size_t)byte, (size_t)line); + info = 0; + } +#endif + if ((ch = *p1) != *p2) { + dfound = 1; + if (xflag) { + (void)printf("%08llx %02x %02x\n", + (long long)byte - 1, ch, *p2); + } else if (lflag) { + if (bflag) + (void)printf("%6lld %3o %c %3o %c\n", + (long long)byte, ch, ch, *p2, *p2); + else + (void)printf("%6lld %3o %3o\n", + (long long)byte, ch, *p2); + } else { + diffmsg(file1, file2, byte, line, ch, *p2); + return (DIFF_EXIT); + } + } + if (ch == '\n') + ++line; + if (++p1 == e1) { + off1 += MMAP_CHUNK; + if ((p1 = m1 = remmap(m1, fd1, off1)) == NULL) { + munmap(m2, MMAP_CHUNK); + err(ERR_EXIT, "remmap %s", file1); + } + e1 = m1 + MMAP_CHUNK; + } + if (++p2 == e2) { + off2 += MMAP_CHUNK; + if ((p2 = m2 = remmap(m2, fd2, off2)) == NULL) { + munmap(m1, MMAP_CHUNK); + err(ERR_EXIT, "remmap %s", file2); + } + e2 = m2 + MMAP_CHUNK; + } + } + munmap(m1, MMAP_CHUNK); + munmap(m2, MMAP_CHUNK); + + if (sigaction(SIGSEGV, &oact, NULL)) + err(ERR_EXIT, "sigaction()"); + + if (len1 != len2) { + eofmsg(len1 > len2 ? file2 : file1); + return (DIFF_EXIT); + } + return (dfound ? DIFF_EXIT : 0); +} + +static u_char * +remmap(u_char *mem, int fd, off_t offset) +{ + if (mem != NULL) + munmap(mem, MMAP_CHUNK); + mem = mmap(NULL, MMAP_CHUNK, PROT_READ, MAP_SHARED, fd, offset); + if (mem == MAP_FAILED) + return (NULL); + madvise(mem, MMAP_CHUNK, MADV_SEQUENTIAL); + return (mem); +} + +static void +segv_handler(int sig __unused) { + static const char msg[] = "cmp: Input/output error (caught SIGSEGV)\n"; + + write(STDERR_FILENO, msg, sizeof(msg)); + _exit(EXIT_FAILURE); +} |