diff options
Diffstat (limited to 'usr.bin/strings')
| -rw-r--r-- | usr.bin/strings/Makefile | 5 | ||||
| -rw-r--r-- | usr.bin/strings/strings.1 | 96 | ||||
| -rw-r--r-- | usr.bin/strings/strings.c | 216 |
3 files changed, 317 insertions, 0 deletions
diff --git a/usr.bin/strings/Makefile b/usr.bin/strings/Makefile new file mode 100644 index 0000000..87f557d --- /dev/null +++ b/usr.bin/strings/Makefile @@ -0,0 +1,5 @@ +# @(#)Makefile 8.1 (Berkeley) 6/6/93 + +PROG= strings + +.include <bsd.prog.mk> diff --git a/usr.bin/strings/strings.1 b/usr.bin/strings/strings.1 new file mode 100644 index 0000000..ceeae10 --- /dev/null +++ b/usr.bin/strings/strings.1 @@ -0,0 +1,96 @@ +.\" Copyright (c) 1980, 1990, 1993 +.\" 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. All advertising materials mentioning features or use of this software +.\" must display the following acknowledgement: +.\" This product includes software developed by the University of +.\" California, Berkeley and its contributors. +.\" 4. 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. +.\" +.\" @(#)strings.1 8.1 (Berkeley) 6/6/93 +.\" +.Dd June 6, 1993 +.Dt STRINGS 1 +.Os BSD 3 +.Sh NAME +.Nm strings +.Nd find printable strings in a file +.Sh SYNOPSIS +.Nm strings +.Op Fl afo +.Op Fl n Ar number +.Op Ar file ... +.Sh DESCRIPTION +.Nm Strings +displays the sequences of printable characters in each of the specified +files, or in the standard input, by default. +By default, a sequence must be at least four characters in length +before being displayed. +.Pp +The options are as follows: +.Bl -tag -width Ds +.It Fl a +By default, +.Nm strings +only searches the text and data segments of object files. +The +.Fl a +option causes +.Nm strings +to search the entire object file. +.It Fl f +Each string is preceded by the name of the file +in which it was found. +.It Fl n +Specifies the minimum number of characters in a sequence to be +.Ar number , +instead of four. +.It Fl o +Each string is preceded by its decimal offset in the +file. +.El +.Pp +.Nm Strings +is useful for identifying random binaries, among other things. +.Sh SEE ALSO +.Xr hexdump 1 +.Sh BUGS +The algorithm for identifying strings is extremely primitive. +In particular, machine code instructions on certain architectures +can resemble sequences of ASCII bytes, which +will fool the algorithm. +.Sh COMPATIBILITY +Historic implementations of +.Nm +only search the initialized data portion of the object file. +This was reasonable as strings were normally stored there. +Given new compiler technology which installs strings in the +text portion of the object file, the default behavior was +changed. +.Sh HISTORY +The +.Nm +command appeared in +.Bx 3.0 . diff --git a/usr.bin/strings/strings.c b/usr.bin/strings/strings.c new file mode 100644 index 0000000..398ccac --- /dev/null +++ b/usr.bin/strings/strings.c @@ -0,0 +1,216 @@ +/* + * Copyright (c) 1980, 1987, 1993 + * 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. All advertising materials mentioning features or use of this software + * must display the following acknowledgement: + * This product includes software developed by the University of + * California, Berkeley and its contributors. + * 4. 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. + */ + +#ifndef lint +static char copyright[] = +"@(#) Copyright (c) 1980, 1987, 1993\n\ + The Regents of the University of California. All rights reserved.\n"; +#endif /* not lint */ + +#ifndef lint +static char sccsid[] = "@(#)strings.c 8.2 (Berkeley) 1/28/94"; +#endif /* not lint */ + +#include <sys/types.h> + +#include <a.out.h> +#include <ctype.h> +#include <errno.h> +#include <fcntl.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <unistd.h> + +#define DEF_LEN 4 /* default minimum string length */ +#define ISSTR(ch) (isascii(ch) && (isprint(ch) || ch == '\t')) + +typedef struct exec EXEC; /* struct exec cast */ + +static long foff; /* offset in the file */ +static int hcnt, /* head count */ + head_len, /* length of header */ + read_len; /* length to read */ +static u_char hbfr[sizeof(EXEC)]; /* buffer for struct exec */ + +static void usage(); + +main(argc, argv) + int argc; + char **argv; +{ + extern char *optarg; + extern int optind; + register int ch, cnt; + register u_char *C; + EXEC *head; + int exitcode, minlen; + short asdata, oflg, fflg; + u_char *bfr; + char *file, *p; + + /* + * for backward compatibility, allow '-' to specify 'a' flag; no + * longer documented in the man page or usage string. + */ + asdata = exitcode = fflg = oflg = 0; + minlen = -1; + while ((ch = getopt(argc, argv, "-0123456789an:of")) != EOF) + switch (ch) { + case '0': case '1': case '2': case '3': case '4': + case '5': case '6': case '7': case '8': case '9': + /* + * kludge: strings was originally designed to take + * a number after a dash. + */ + if (minlen == -1) { + p = argv[optind - 1]; + if (p[0] == '-' && p[1] == ch && !p[2]) + minlen = atoi(++p); + else + minlen = atoi(argv[optind] + 1); + } + break; + case '-': + case 'a': + asdata = 1; + break; + case 'f': + fflg = 1; + break; + case 'n': + minlen = atoi(optarg); + break; + case 'o': + oflg = 1; + break; + case '?': + default: + usage(); + } + argc -= optind; + argv += optind; + + if (minlen == -1) + minlen = DEF_LEN; + else { + (void)fprintf(stderr, "strings: length less than 1\n"); + exit (1); + } + + if (!(bfr = malloc((u_int)minlen))) { + (void)fprintf(stderr, "strings: %s\n", strerror(errno)); + exit(1); + } + bfr[minlen] = '\0'; + file = "stdin"; + do { + if (*argv) { + file = *argv++; + if (!freopen(file, "r", stdin)) { + (void)fprintf(stderr, + "strings: %s: %s\n", file, strerror(errno)); + exitcode = 1; + goto nextfile; + } + } + foff = 0; +#define DO_EVERYTHING() {read_len = -1; head_len = 0; goto start;} + read_len = -1; + if (asdata) + DO_EVERYTHING() + else { + head = (EXEC *)hbfr; + if ((head_len = + read(fileno(stdin), head, sizeof(EXEC))) == -1) + DO_EVERYTHING() + if (head_len == sizeof(EXEC) && !N_BADMAG(*head)) { + foff = N_TXTOFF(*head); + if (fseek(stdin, foff, SEEK_SET) == -1) + DO_EVERYTHING() + read_len = head->a_text + head->a_data; + head_len = 0; + } + else + hcnt = 0; + } +start: + for (cnt = 0; (ch = getch()) != EOF;) { + if (ISSTR(ch)) { + if (!cnt) + C = bfr; + *C++ = ch; + if (++cnt < minlen) + continue; + if (fflg) + printf("%s:", file); + if (oflg) + printf("%07ld %s", + foff - minlen, (char *)bfr); + else + printf("%s", bfr); + while ((ch = getch()) != EOF && ISSTR(ch)) + putchar((char)ch); + putchar('\n'); + } + cnt = 0; + } +nextfile: ; + } while (*argv); + exit(exitcode); +} + +/* + * getch -- + * get next character from wherever + */ +getch() +{ + ++foff; + if (head_len) { + if (hcnt < head_len) + return((int)hbfr[hcnt++]); + head_len = 0; + } + if (read_len == -1 || read_len-- > 0) + return(getchar()); + return(EOF); +} + +static void +usage() +{ + (void)fprintf(stderr, + "usage: strings [-afo] [-n length] [file ... ]\n"); + exit(1); +} |
