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1 | /* |
2 | * Copyright (c) 2003 Silicon Graphics, Inc. All Rights Reserved. | |
dfc130f3 | 3 | * |
e246ba5f NS |
4 | * This program is free software; you can redistribute it and/or modify it |
5 | * under the terms of version 2 of the GNU General Public License as | |
6 | * published by the Free Software Foundation. | |
dfc130f3 | 7 | * |
e246ba5f NS |
8 | * This program is distributed in the hope that it would be useful, but |
9 | * WITHOUT ANY WARRANTY; without even the implied warranty of | |
10 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. | |
dfc130f3 | 11 | * |
e246ba5f NS |
12 | * Further, this software is distributed without any warranty that it is |
13 | * free of the rightful claim of any third person regarding infringement | |
14 | * or the like. Any license provided herein, whether implied or | |
15 | * otherwise, applies only to this software file. Patent licenses, if | |
16 | * any, provided herein do not apply to combinations of this program with | |
17 | * other software, or any other product whatsoever. | |
dfc130f3 | 18 | * |
e246ba5f NS |
19 | * You should have received a copy of the GNU General Public License along |
20 | * with this program; if not, write the Free Software Foundation, Inc., 59 | |
21 | * Temple Place - Suite 330, Boston MA 02111-1307, USA. | |
dfc130f3 | 22 | * |
e246ba5f NS |
23 | * Contact information: Silicon Graphics, Inc., 1600 Amphitheatre Pkwy, |
24 | * Mountain View, CA 94043, or: | |
dfc130f3 RC |
25 | * |
26 | * http://www.sgi.com | |
27 | * | |
28 | * For further information regarding this notice, see: | |
29 | * | |
e246ba5f NS |
30 | * http://oss.sgi.com/projects/GenInfo/SGIGPLNoticeExplan/ |
31 | */ | |
32 | ||
33 | #include <libxfs.h> | |
34 | #include <ctype.h> | |
35 | #include "command.h" | |
36 | #include "input.h" | |
37 | #include "init.h" | |
38 | ||
39 | static cmdinfo_t pread_cmd; | |
40 | ||
41 | static void | |
42 | pread_help(void) | |
43 | { | |
44 | printf(_( | |
45 | "\n" | |
46 | " reads a range of bytes in a specified block size from the given offset\n" | |
47 | "\n" | |
48 | " Example:\n" | |
49 | " 'read -v 512 20' - dumps 20 bytes read from 512 bytes into the file\n" | |
50 | "\n" | |
51 | " Reads a segment of the currently open file, optionally dumping it to the\n" | |
52 | " standard output stream (with -v option) for subsequent inspection.\n" | |
53 | " The reads are performed in sequential blocks starting at offset, with the\n" | |
54 | " blocksize tunable using the -b option (default blocksize is 4096 bytes).\n" | |
55 | "\n")); | |
56 | } | |
57 | ||
58 | void *buffer; | |
59 | ssize_t buffersize; | |
60 | ||
61 | int | |
62 | alloc_buffer( | |
63 | ssize_t bsize, | |
64 | unsigned int seed) | |
65 | { | |
66 | if (bsize > buffersize) { | |
ae8d6a95 | 67 | if (buffer) |
68 | free(buffer); | |
69 | buffer = memalign(getpagesize(), buffersize = bsize); | |
e246ba5f | 70 | if (!buffer) { |
ae8d6a95 | 71 | perror("memalign"); |
e246ba5f NS |
72 | buffersize = 0; |
73 | return 0; | |
74 | } | |
75 | } | |
76 | memset(buffer, seed, buffersize); | |
77 | return 1; | |
78 | } | |
79 | ||
80 | static void | |
81 | dump_buffer( | |
82 | off64_t offset, | |
83 | ssize_t len) | |
84 | { | |
85 | int i, j; | |
86 | char *p; | |
87 | ||
88 | for (i = 0, p = (char *)buffer; i < len; i += 16) { | |
89 | char *s = p; | |
90 | ||
91 | printf("%08llx: ", (off64_t)i + offset); | |
92 | for (j = 0; j < 16 && i + j < len; j++, p++) | |
93 | printf("%02x ", *p); | |
94 | printf(" "); | |
95 | for (j = 0; j < 16 && i + j < len; j++, s++) { | |
93d9f139 | 96 | if (isalnum((int)*s)) |
e246ba5f NS |
97 | printf("%c", *s); |
98 | else | |
99 | printf("."); | |
100 | } | |
101 | printf("\n"); | |
102 | } | |
103 | } | |
104 | ||
105 | int | |
106 | read_buffer( | |
107 | int fd, | |
108 | off64_t offset, | |
109 | ssize_t count, | |
110 | ssize_t *total, | |
111 | int verbose, | |
112 | int onlyone) | |
113 | { | |
114 | ssize_t bytes; | |
115 | ||
116 | *total = 0; | |
117 | while (count > 0) { | |
118 | bytes = pread64(fd, buffer, min(count,buffersize), offset); | |
119 | if (bytes == 0) | |
120 | break; | |
121 | if (bytes < 0) { | |
122 | perror("pread64"); | |
123 | return 0; | |
124 | } | |
125 | if (verbose) | |
126 | dump_buffer(offset, bytes); | |
127 | *total += bytes; | |
128 | if (onlyone || bytes < count) | |
129 | break; | |
130 | offset += bytes; | |
131 | count -= bytes; | |
132 | } | |
133 | return 1; | |
134 | } | |
135 | ||
136 | static int | |
137 | pread_f( | |
138 | int argc, | |
139 | char **argv) | |
140 | { | |
141 | off64_t offset; | |
142 | ssize_t count, total; | |
143 | unsigned int bsize = 4096; | |
144 | char *sp; | |
145 | int vflag = 0; | |
146 | int c; | |
147 | ||
148 | while ((c = getopt(argc, argv, "b:v")) != EOF) { | |
149 | switch (c) { | |
150 | case 'b': | |
151 | bsize = strtoul(optarg, &sp, 0); | |
152 | if (!sp || sp == optarg) { | |
153 | printf(_("non-numeric bsize -- %s\n"), optarg); | |
154 | return 0; | |
155 | } | |
156 | break; | |
157 | case 'v': | |
158 | vflag = 1; | |
159 | break; | |
160 | default: | |
161 | printf("%s %s\n", pread_cmd.name, pread_cmd.oneline); | |
162 | return 0; | |
163 | } | |
164 | } | |
165 | if (optind != argc - 2) { | |
166 | printf("%s %s\n", pread_cmd.name, pread_cmd.oneline); | |
167 | return 0; | |
168 | } | |
169 | offset = strtoul(argv[optind], &sp, 0); | |
170 | if (!sp || sp == argv[optind]) { | |
171 | printf(_("non-numeric offset argument -- %s\n"), argv[optind]); | |
172 | return 0; | |
173 | } | |
174 | optind++; | |
175 | count = strtoul(argv[optind], &sp, 0); | |
176 | if (!sp || sp == argv[optind]) { | |
177 | printf(_("non-numeric length argument -- %s\n"), argv[optind]); | |
178 | return 0; | |
179 | } | |
180 | ||
181 | if (!alloc_buffer(bsize, 0xabababab)) | |
182 | return 0; | |
183 | ||
184 | if (!read_buffer(fdesc, offset, count, &total, vflag, 0)) | |
185 | return 0; | |
186 | ||
187 | printf(_("read %u/%u bytes at offset %llu\n"), total, count, offset); | |
188 | return 0; | |
189 | } | |
190 | ||
191 | void | |
192 | pread_init(void) | |
193 | { | |
194 | pread_cmd.name = _("pread"); | |
195 | pread_cmd.altname = _("r"); | |
196 | pread_cmd.cfunc = pread_f; | |
197 | pread_cmd.argmin = 2; | |
198 | pread_cmd.argmax = -1; | |
199 | pread_cmd.args = _("[-b bs] [-v] off len"); | |
200 | pread_cmd.oneline = _("reads a number of bytes at a specified offset"); | |
201 | pread_cmd.help = pread_help; | |
202 | ||
203 | add_command(&pread_cmd); | |
204 | } |