cosmopolitan/tool/decode/ar.c

147 lines
5.2 KiB
C

/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi│
╞══════════════════════════════════════════════════════════════════════════════╡
│ Copyright 2020 Justine Alexandra Roberts Tunney │
│ │
│ This program is free software; you can redistribute it and/or modify │
│ it under the terms of the GNU General Public License as published by │
│ the Free Software Foundation; version 2 of the License. │
│ │
│ This program is distributed in the hope that it will be useful, but │
│ WITHOUT ANY WARRANTY; without even the implied warranty of │
│ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU │
│ General Public License for more details. │
│ │
│ You should have received a copy of the GNU General Public License │
│ along with this program; if not, write to the Free Software │
│ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA │
│ 02110-1301 USA │
╚─────────────────────────────────────────────────────────────────────────────*/
#include "libc/bits/bits.h"
#include "libc/calls/calls.h"
#include "libc/calls/struct/stat.h"
#include "libc/fmt/conv.h"
#include "libc/log/check.h"
#include "libc/log/log.h"
#include "libc/mem/mem.h"
#include "libc/runtime/runtime.h"
#include "libc/stdio/stdio.h"
#include "libc/str/str.h"
#include "libc/sysv/consts/map.h"
#include "libc/sysv/consts/o.h"
#include "libc/sysv/consts/prot.h"
#include "libc/x/x.h"
#define AR_MAGIC1 "!<arch>\n"
#define AR_MAGIC2 "`\n"
/**
* ar rU doge.a NOTICE # create archive and use non-deterministic stuff
* o//tool/decode/ar.com doge.a
*/
static int fd;
static uint8_t *data;
static long size;
static const char *path;
static struct stat st;
static void PrintString(uint8_t *p, long n, const char *name) {
char *s;
s = xmalloc(n + 1);
s[n] = '\0';
memcpy(s, p, n);
printf("\t.ascii\t%`'.*s\t\t\t# %s\n", n, s, name);
free(s);
}
static void Open(void) {
if ((fd = open(path, O_RDONLY)) == -1) {
fprintf(stderr, "error: open() failed: %s\n", path);
exit(1);
}
CHECK_NE(-1, fstat(fd, &st));
if (!(size = st.st_size)) exit(0);
CHECK_NE(MAP_FAILED,
(data = mmap(NULL, size, PROT_READ, MAP_PRIVATE, fd, 0)));
LOGIFNEG1(close(fd));
}
static void Close(void) {
LOGIFNEG1(munmap(data, size));
}
static void Check(void) {
if (size < 8 + 60 + 4 ||
(memcmp(data, AR_MAGIC1, strlen(AR_MAGIC1)) != 0 ||
memcmp(data + 66, AR_MAGIC2, strlen(AR_MAGIC2)) != 0)) {
fprintf(stderr, "error: not a unix archive: %s\n", path);
exit(1);
}
}
static void PrintTable(void) {
}
static void PrintHeader(uint8_t *p) {
PrintString(p + 0, 16, "file identifier [ascii]");
PrintString(p + 16, 12, "file modification timestamp [decimal]");
PrintString(p + 28, 6, "owner id [decimal]");
PrintString(p + 34, 6, "group id [decimal]");
PrintString(p + 40, 8, "file mode [octal] (type and permission)");
PrintString(p + 48, 10, "file size in bytes [decimal]");
PrintString(p + 58, 2, "ending characters");
}
static void Print(void) {
int arsize;
uint8_t *b, *p;
uint64_t offset;
uint32_t i, n, o, table, entries, symbols, symbolslen;
arsize = atoi((char *)(data + 8 + 48));
CHECK_LE(4, arsize);
CHECK_LE(8 + 60 + arsize, size);
entries = read32be(data + 8 + 60);
CHECK_LE(4 + entries * 4 + 1, arsize);
printf("\t# %'s\n", path);
PrintString(data, 8, "file signature");
PrintHeader(data + 8);
printf("\n");
printf("\t.long\t%u\t\t\t# %s\n", entries, "symbol table entries");
table = 8 + 60 + 4;
for (i = 0; i < entries; ++i) {
printf("\t.long\t%#x\t\t\t\t# %u\n", read32be(data + table + i * 4), i);
}
symbols = table + entries * 4;
symbolslen = arsize - (4 + entries * 4);
for (i = o = 0; o < symbolslen; ++i, o += n + 1) {
b = data + symbols + o;
CHECK_NOTNULL((p = memchr(b, '\0', symbolslen - (symbols + o))));
n = p - b;
printf("\t.asciz\t%#`'.*s\t\t\t# %u\n", n, b, i);
}
offset = 8 + 60 + arsize;
while (offset < size) {
offset += offset & 1;
CHECK_LE(offset + 60, size);
CHECK_EQ(0, memcmp(data + offset + 58, AR_MAGIC2, strlen(AR_MAGIC2)));
arsize = atoi((char *)(data + offset + 48));
CHECK_LE(offset + 60 + arsize, size);
printf("\n");
PrintHeader(data + offset);
offset += 60 + arsize;
}
}
int main(int argc, char *argv[]) {
if (argc < 2) return 1;
path = argv[1];
Open();
Check();
Print();
Close();
return 0;
}