ref: faa625a1d5ab47ac0438b2cea5b2bde1ea747b8b
dir: /sys/src/cmd/gzip/gunzip.c/
#include <u.h> #include <libc.h> #include <bio.h> #include <flate.h> #include "gzip.h" typedef struct GZHead GZHead; struct GZHead { ulong mtime; char *file; }; static int crcwrite(void *bout, void *buf, int n); static int get1(Biobuf *b); static ulong get4(Biobuf *b); static int gunzipf(char *file, int stdout); static int gunzip(int ofd, char *ofile, Biobuf *bin); static void header(Biobuf *bin, GZHead *h); static void trailer(Biobuf *bin, long wlen); static void error(char*, ...); #pragma varargck argpos error 1 static Biobuf bin; static ulong crc; static ulong *crctab; static int debug; static char *delfile; static vlong gzok; static char *infile; static int settimes; static int table; static int verbose; static int wbad; static ulong wlen; static jmp_buf zjmp; void usage(void) { fprint(2, "usage: gunzip [-ctvTD] [file ....]\n"); exits("usage"); } void main(int argc, char *argv[]) { int i, ok, stdout; stdout = 0; ARGBEGIN{ case 'D': debug++; break; case 'c': stdout++; break; case 't': table++; break; case 'T': settimes++; break; case 'v': verbose++; break; default: usage(); break; }ARGEND crctab = mkcrctab(GZCRCPOLY); ok = inflateinit(); if(ok != FlateOk) sysfatal("inflateinit failed: %s", flateerr(ok)); if(argc == 0){ Binit(&bin, 0, OREAD); settimes = 0; infile = "<stdin>"; ok = gunzip(1, "<stdout>", &bin); }else{ ok = 1; if(stdout) settimes = 0; for(i = 0; i < argc; i++) ok &= gunzipf(argv[i], stdout); } exits(ok ? nil: "errors"); } static int gunzipf(char *file, int stdout) { char ofile[256], *s; int ofd, ifd, ok; infile = file; ifd = open(file, OREAD); if(ifd < 0){ fprint(2, "gunzip: can't open %s: %r\n", file); return 0; } Binit(&bin, ifd, OREAD); if(Bgetc(&bin) != GZMAGIC1 || Bgetc(&bin) != GZMAGIC2 || Bgetc(&bin) != GZDEFLATE){ fprint(2, "gunzip: %s is not a gzip deflate file\n", file); Bterm(&bin); close(ifd); return 0; } Bungetc(&bin); Bungetc(&bin); Bungetc(&bin); if(table) ofd = -1; else if(stdout){ ofd = 1; strcpy(ofile, "<stdout>"); }else{ s = strrchr(file, '/'); if(s != nil) s++; else s = file; strecpy(ofile, ofile+sizeof ofile, s); s = strrchr(ofile, '.'); if(s != nil && s != ofile && strcmp(s, ".gz") == 0) *s = '\0'; else if(s != nil && strcmp(s, ".tgz") == 0) strcpy(s, ".tar"); else if(strcmp(file, ofile) == 0){ fprint(2, "gunzip: can't overwrite %s\n", file); Bterm(&bin); close(ifd); return 0; } ofd = create(ofile, OWRITE, 0666); if(ofd < 0){ fprint(2, "gunzip: can't create %s: %r\n", ofile); Bterm(&bin); close(ifd); return 0; } delfile = ofile; } wbad = 0; ok = gunzip(ofd, ofile, &bin); Bterm(&bin); close(ifd); if(wbad){ fprint(2, "gunzip: can't write %s: %r\n", ofile); if(delfile) remove(delfile); } delfile = nil; if(!stdout && ofd >= 0) close(ofd); return ok; } static int gunzip(int ofd, char *ofile, Biobuf *bin) { Dir *d; GZHead h; int err; h.file = nil; gzok = 0; for(;;){ if(Bgetc(bin) < 0) return 1; Bungetc(bin); if(setjmp(zjmp)) return 0; header(bin, &h); gzok = 0; wlen = 0; crc = 0; if(!table && verbose) fprint(2, "extracting %s to %s\n", h.file, ofile); err = inflate((void*)ofd, crcwrite, bin, (int(*)(void*))Bgetc); if(err != FlateOk) error("inflate failed: %s", flateerr(err)); trailer(bin, wlen); if(table){ if(verbose) print("%-32s %10ld %s", h.file, wlen, ctime(h.mtime)); else print("%s\n", h.file); }else if(settimes && h.mtime && (d=dirfstat(ofd)) != nil){ d->mtime = h.mtime; dirfwstat(ofd, d); free(d); } free(h.file); h.file = nil; gzok = Boffset(bin); } } static void header(Biobuf *bin, GZHead *h) { char *s; int i, c, flag, ns, nsa; if(get1(bin) != GZMAGIC1 || get1(bin) != GZMAGIC2) error("bad gzip file magic"); if(get1(bin) != GZDEFLATE) error("unknown compression type"); flag = get1(bin); if(flag & ~(GZFTEXT|GZFEXTRA|GZFNAME|GZFCOMMENT|GZFHCRC)) fprint(2, "gunzip: reserved flags set, data may not be decompressed correctly\n"); /* mod time */ h->mtime = get4(bin); /* extra flags */ get1(bin); /* OS type */ get1(bin); if(flag & GZFEXTRA){ i = get1(bin); i |= get1(bin)<<8; for(; i>0; i--) get1(bin); } /* name */ if(flag & GZFNAME){ nsa = 32; ns = 0; s = malloc(nsa); if(s == nil) error("out of memory"); while((c = get1(bin)) != 0){ s[ns++] = c; if(ns >= nsa){ nsa += 32; s = realloc(s, nsa); if(s == nil) error("out of memory"); } } s[ns] = '\0'; h->file = s; }else h->file = strdup("<unnamed file>"); /* comment */ if(flag & GZFCOMMENT) while(get1(bin) != 0) ; /* crc16 */ if(flag & GZFHCRC){ get1(bin); get1(bin); } } static void trailer(Biobuf *bin, long wlen) { ulong tcrc; long len; tcrc = get4(bin); if(tcrc != crc) error("crc mismatch"); len = get4(bin); if(len != wlen) error("bad output length: expected %lud got %lud", wlen, len); } static ulong get4(Biobuf *b) { ulong v; int i, c; v = 0; for(i = 0; i < 4; i++){ c = Bgetc(b); if(c < 0) error("unexpected eof reading file information"); v |= c << (i * 8); } return v; } static int get1(Biobuf *b) { int c; c = Bgetc(b); if(c < 0) error("unexpected eof reading file information"); return c; } static int crcwrite(void *out, void *buf, int n) { int fd, nw; wlen += n; crc = blockcrc(crctab, crc, buf, n); fd = (int)(uintptr)out; if(fd < 0) return n; nw = write(fd, buf, n); if(nw != n) wbad = 1; return nw; } static void error(char *fmt, ...) { va_list arg; if(gzok) fprint(2, "gunzip: %s: corrupted data after byte %lld ignored\n", infile, gzok); else{ fprint(2, "gunzip: "); if(infile) fprint(2, "%s: ", infile); va_start(arg, fmt); vfprint(2, fmt, arg); va_end(arg); fprint(2, "\n"); if(delfile != nil){ fprint(2, "gunzip: removing output file %s\n", delfile); remove(delfile); delfile = nil; } } longjmp(zjmp, 1); }