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attozip.c
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attozip.c
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/* attozip - extremely compact and minimal "zip" (non-)implementation
* 2012 Kieran Clancy <clancy DOT kieran AT gmail>
* Licensed under GPLv3 - see LICENSE
*/
#include <sys/types.h>
#include <sys/stat.h>
#include <stdlib.h>
#include <unistd.h>
#include <fcntl.h>
#include <string.h>
#include <limits.h>
#include <dirent.h>
#include <arpa/inet.h>
#include <time.h>
#define PBUF 2048
#define RBUF 4096
static void zip_path(int zip, int dirfd, const char *path);
static void zip_file(int zip, char *path, int fd, struct stat *st);
static void zip_build_directory(int zip);
static void path_add(char *buf, int bufsz, const char *add);
static uint32_t msdos_time(struct tm *t);
static uint16_t zip_perms(mode_t mode);
static uint32_t crc32_add(uint32_t crc32, const uint8_t *buf, size_t n);
static void write_32_le(int fd, uint32_t x);
static void write_16_le(int fd, uint16_t x);
static void xerr(const char *str);
static void xerr2(const char *a, const char *b);
typedef struct zipindex {
char *fname;
int namelen;
off_t offset;
uint32_t time;
uint32_t crc32;
uint32_t size;
uint16_t perms;
struct zipindex *next;
} zipindex_t;
static zipindex_t zindex = { 0 };
int main(int argc, char *argv[]) {
int zip, i;
if (argc < 3) xerr("Usage: attozip new.zip file1 ...\n"
" Copyright 2012 Kieran Clancy\n"
" http://git.io/ZaUszg");
zip = open(argv[1], O_CREAT|O_EXCL|O_RDWR, 0644);
if (zip < 0) xerr2(argv[1], "could not create or already exists");
for (i=2; i<argc; i++) zip_path(zip, AT_FDCWD, argv[i]);
zip_build_directory(zip);
return 0;
}
static void zip_path(int zip, int dirfd, const char *path) {
static char zpath[PBUF] = "";
struct stat st;
struct dirent *dent;
char *fname;
int in, zpathlen;
char islink;
DIR *d;
if (!path || !*path) xerr("invalid path.");
islink = 0;
readlinkat(dirfd, path, &islink, 1);
if (islink) xerr("symlinks not supported.");
in = openat(dirfd, path, O_RDONLY);
zpathlen = strlen(zpath);
path_add(zpath, PBUF, path);
if (in < 0 || fstat(in, &st)) {
xerr2(zpath, "could not open");
}
/* regular file */
if (S_ISREG(st.st_mode)) {
zip_file(zip, zpath, in, &st);
close(in);
goto cleanup;
zpath[zpathlen] = '\0';
}
/* otherwise, only allow directories */
if (!S_ISDIR(st.st_mode)) xerr2(zpath, "unexpected file type");
d = fdopendir(in);
if (!d) xerr2(zpath, "could not open");
while ((dent = readdir(d))) {
fname = dent->d_name;
if (!fname || !*fname) xerr2(zpath, "has bad file entry");
if (fname[0] == '.' && (fname[1] == '\0'
|| (fname[1] == '.' && fname[2] == '\0'))) {
continue;
}
zip_path(zip, in, fname);
}
closedir(d);
cleanup:
zpath[zpathlen] = '\0';
}
#define zwrite(s,n) do { \
if (write(zip, s, n) < 0) xerr("write error"); \
} while (0)
#define zw32le(x) write_32_le(zip, x)
#define zw16le(x) write_16_le(zip, x)
#define zseek(o,w) do { \
if (lseek(zip, o, w) < 0) xerr("seek error"); \
} while (0)
static void zip_file(int zip, char *path, int fd, struct stat *st) {
static uint8_t buf[RBUF];
zipindex_t *indp = &zindex;
int rbytes;
if (!path || !*path) xerr("bad path");
while (indp->fname) {
if (strcmp(indp->fname, path) == 0) xerr2(path, "duplicate path");
indp = indp->next;
}
indp->fname = strdup(path);
indp->next = calloc(1, sizeof(*indp));
if (!indp->fname || !indp->next) xerr("out of memory");
indp->namelen = strlen(path);
indp->offset = lseek(zip, 0, SEEK_CUR);
indp->time = msdos_time(localtime(&(st->st_mtime)));
indp->perms = zip_perms(st->st_mode);
zwrite("\x50\x4b\x03\x04\x0a\x00\x00\x00\x00\x00", 10);
zw32le(indp->time);
zwrite("\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00", 12);
zw16le(indp->namelen);
zwrite("\x00\x00", 2);
zwrite(indp->fname, indp->namelen);
indp->size = 0;
indp->crc32 = 0;
do {
rbytes = read(fd, buf, RBUF);
if (rbytes == 0) break;
if (rbytes < 0) xerr2(path, "read error");
zwrite(buf, rbytes);
indp->size += rbytes;
indp->crc32 = crc32_add(indp->crc32, buf, rbytes);
} while (1);
zseek(indp->offset + 14, SEEK_SET);
zw32le(indp->crc32);
zw32le(indp->size);
zw32le(indp->size);
zseek(4 + indp->namelen + indp->size, SEEK_CUR);
}
static void zip_build_directory(int zip) {
uint16_t files = 0;
uint32_t d_offset, eod_offset;
zipindex_t *indp = &zindex;
d_offset = lseek(zip, 0, SEEK_END);
while (indp->fname) {
zwrite("\x50\x4b\x01\x02\x1e\x03\x0a\x00\x00\x00\x00\x00", 12);
zw32le(indp->time);
zw32le(indp->crc32);
zw32le(indp->size);
zw32le(indp->size);
zw16le(indp->namelen);
zwrite("\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00", 10);
zw16le(indp->perms);
zw32le(indp->offset);
zwrite(indp->fname, indp->namelen);
files++;
indp = indp->next;
}
/* end of central directory */
eod_offset = lseek(zip, 0, SEEK_END);
zwrite("\x50\x4b\x05\x06\x00\x00\x00\x00", 8);
zw16le(files);
zw16le(files);
zw32le(eod_offset-d_offset);
zw32le(d_offset);
zwrite("\x00\x00", 2);
}
static void path_add(char *buf, int bufsz, const char *add) {
char *p;
int len, exdepth;
if (!add) return;
exdepth = (buf[0] == '\0' ? -1 : 0);
while (*add) {
while (*add == '/') add++;
len = 0;
while (add[len] != '\0' && add[len] != '/') len++;
if (len == 0 || (len == 1 && add[0] == '.')) goto next_component;
if (len == 2 && add[0] == '.' && add[1] == '.') {
if (exdepth-- == 0) xerr("unexpected /../ in path");
if (!(p = strrchr(buf, '/'))) p = buf;
*p = '\0';
goto next_component;
}
if (strlen(buf) + 1 + len + 1 > bufsz) xerr("path too long");
if (buf[0]) strcat(buf, "/");
strncat(buf, add, len);
if (exdepth >= 0) exdepth++;
next_component:
add += len;
}
}
static uint32_t msdos_time(struct tm *t) {
if (!t) xerr("time not set");
/* needs to be written as little-endian */
return (((( /* 7bit */ (t->tm_year-80)
<< 4 ^ (t->tm_mon+1 ))
<< 5 ^ (t->tm_mday ))
<< 5 ^ (t->tm_hour ))
<< 6 ^ (t->tm_min ))
<< 5 ^ (t->tm_sec/2 );
}
static uint16_t zip_perms(mode_t mode) {
if ((mode & S_IFMT) != S_IFREG) xerr("zipping non-file?");
return mode & (S_IFMT | 07777);
}
static uint32_t crc32_add(uint32_t crc32, const uint8_t *buf, size_t n) {
/* divisions by polynomial 0x[1]04c11db7 for little-endian output */
/* CRC32 algorithm and table generation is publicly documented */
static const uint32_t c32t[256] = { 0x00000000, 0x77073096, 0xee0e612c,
0x990951ba, 0x076dc419, 0x706af48f, 0xe963a535, 0x9e6495a3, 0x0edb8832,
0x79dcb8a4, 0xe0d5e91e, 0x97d2d988, 0x09b64c2b, 0x7eb17cbd, 0xe7b82d07,
0x90bf1d91, 0x1db71064, 0x6ab020f2, 0xf3b97148, 0x84be41de, 0x1adad47d,
0x6ddde4eb, 0xf4d4b551, 0x83d385c7, 0x136c9856, 0x646ba8c0, 0xfd62f97a,
0x8a65c9ec, 0x14015c4f, 0x63066cd9, 0xfa0f3d63, 0x8d080df5, 0x3b6e20c8,
0x4c69105e, 0xd56041e4, 0xa2677172, 0x3c03e4d1, 0x4b04d447, 0xd20d85fd,
0xa50ab56b, 0x35b5a8fa, 0x42b2986c, 0xdbbbc9d6, 0xacbcf940, 0x32d86ce3,
0x45df5c75, 0xdcd60dcf, 0xabd13d59, 0x26d930ac, 0x51de003a, 0xc8d75180,
0xbfd06116, 0x21b4f4b5, 0x56b3c423, 0xcfba9599, 0xb8bda50f, 0x2802b89e,
0x5f058808, 0xc60cd9b2, 0xb10be924, 0x2f6f7c87, 0x58684c11, 0xc1611dab,
0xb6662d3d, 0x76dc4190, 0x01db7106, 0x98d220bc, 0xefd5102a, 0x71b18589,
0x06b6b51f, 0x9fbfe4a5, 0xe8b8d433, 0x7807c9a2, 0x0f00f934, 0x9609a88e,
0xe10e9818, 0x7f6a0dbb, 0x086d3d2d, 0x91646c97, 0xe6635c01, 0x6b6b51f4,
0x1c6c6162, 0x856530d8, 0xf262004e, 0x6c0695ed, 0x1b01a57b, 0x8208f4c1,
0xf50fc457, 0x65b0d9c6, 0x12b7e950, 0x8bbeb8ea, 0xfcb9887c, 0x62dd1ddf,
0x15da2d49, 0x8cd37cf3, 0xfbd44c65, 0x4db26158, 0x3ab551ce, 0xa3bc0074,
0xd4bb30e2, 0x4adfa541, 0x3dd895d7, 0xa4d1c46d, 0xd3d6f4fb, 0x4369e96a,
0x346ed9fc, 0xad678846, 0xda60b8d0, 0x44042d73, 0x33031de5, 0xaa0a4c5f,
0xdd0d7cc9, 0x5005713c, 0x270241aa, 0xbe0b1010, 0xc90c2086, 0x5768b525,
0x206f85b3, 0xb966d409, 0xce61e49f, 0x5edef90e, 0x29d9c998, 0xb0d09822,
0xc7d7a8b4, 0x59b33d17, 0x2eb40d81, 0xb7bd5c3b, 0xc0ba6cad, 0xedb88320,
0x9abfb3b6, 0x03b6e20c, 0x74b1d29a, 0xead54739, 0x9dd277af, 0x04db2615,
0x73dc1683, 0xe3630b12, 0x94643b84, 0x0d6d6a3e, 0x7a6a5aa8, 0xe40ecf0b,
0x9309ff9d, 0x0a00ae27, 0x7d079eb1, 0xf00f9344, 0x8708a3d2, 0x1e01f268,
0x6906c2fe, 0xf762575d, 0x806567cb, 0x196c3671, 0x6e6b06e7, 0xfed41b76,
0x89d32be0, 0x10da7a5a, 0x67dd4acc, 0xf9b9df6f, 0x8ebeeff9, 0x17b7be43,
0x60b08ed5, 0xd6d6a3e8, 0xa1d1937e, 0x38d8c2c4, 0x4fdff252, 0xd1bb67f1,
0xa6bc5767, 0x3fb506dd, 0x48b2364b, 0xd80d2bda, 0xaf0a1b4c, 0x36034af6,
0x41047a60, 0xdf60efc3, 0xa867df55, 0x316e8eef, 0x4669be79, 0xcb61b38c,
0xbc66831a, 0x256fd2a0, 0x5268e236, 0xcc0c7795, 0xbb0b4703, 0x220216b9,
0x5505262f, 0xc5ba3bbe, 0xb2bd0b28, 0x2bb45a92, 0x5cb36a04, 0xc2d7ffa7,
0xb5d0cf31, 0x2cd99e8b, 0x5bdeae1d, 0x9b64c2b0, 0xec63f226, 0x756aa39c,
0x026d930a, 0x9c0906a9, 0xeb0e363f, 0x72076785, 0x05005713, 0x95bf4a82,
0xe2b87a14, 0x7bb12bae, 0x0cb61b38, 0x92d28e9b, 0xe5d5be0d, 0x7cdcefb7,
0x0bdbdf21, 0x86d3d2d4, 0xf1d4e242, 0x68ddb3f8, 0x1fda836e, 0x81be16cd,
0xf6b9265b, 0x6fb077e1, 0x18b74777, 0x88085ae6, 0xff0f6a70, 0x66063bca,
0x11010b5c, 0x8f659eff, 0xf862ae69, 0x616bffd3, 0x166ccf45, 0xa00ae278,
0xd70dd2ee, 0x4e048354, 0x3903b3c2, 0xa7672661, 0xd06016f7, 0x4969474d,
0x3e6e77db, 0xaed16a4a, 0xd9d65adc, 0x40df0b66, 0x37d83bf0, 0xa9bcae53,
0xdebb9ec5, 0x47b2cf7f, 0x30b5ffe9, 0xbdbdf21c, 0xcabac28a, 0x53b39330,
0x24b4a3a6, 0xbad03605, 0xcdd70693, 0x54de5729, 0x23d967bf, 0xb3667a2e,
0xc4614ab8, 0x5d681b02, 0x2a6f2b94, 0xb40bbe37, 0xc30c8ea1, 0x5a05df1b,
0x2d02ef8d };
int i;
register uint32_t crc = ~crc32;
for (i=0; i<n; i++) {
crc = c32t[buf[i] ^ (crc & 0xff)] ^ (crc >> 8);
}
return ~crc;
}
static void write_32_le(int fd, uint32_t x) {
x = htonl(x);
x = (x & 0xff) << 24
^ (x >> 8 & 0xff) << 16
^ (x >> 16 & 0xff) << 8
^ (x >> 24);
write(fd, &x, 4);
}
static void write_16_le(int fd, uint16_t x) {
x = htons(x);
x = (x & 0xff) << 8
^ (x >> 8);
write(fd, &x, 2);
}
static void xerr(const char *str) {
write(2, str, strlen(str));
write(2, "\n", 1);
exit(1);
}
static void xerr2(const char *a, const char *b) {
write(2, a, strlen(a));
write(2, ": ", 2);
xerr(b);
}