projects / unix-history / blame
| Commit | Line | Data |
|---|---|---|
| b5802654 C |
1 | /* |
| 2 | * compress routines: | |
| 3 | * zmagic() - returns 0 if not recognized, uncompresses and prints | |
| 4 | * information if recognized | |
| 5 | * uncompress(method, old, n, newch) - uncompress old into new, | |
| 6 | * using method, return sizeof new | |
| 7 | * $Id: compress.c,v 1.7 1993/10/27 20:59:05 christos Exp $ | |
| 8 | */ | |
| 9 | #include <stdio.h> | |
| 10 | #include <stdlib.h> | |
| 11 | #include <unistd.h> | |
| 12 | #include <string.h> | |
| 13 | #include <sys/wait.h> | |
| 14 | ||
| 15 | #include "file.h" | |
| 16 | ||
| 17 | static struct { | |
| 18 | char *magic; | |
| 19 | int maglen; | |
| 20 | char *argv[3]; | |
| 21 | int silent; | |
| 22 | } compr[] = { | |
| 23 | { "\037\235", 2, { "uncompress", "-c", NULL }, 0 }, | |
| 24 | { "\037\213", 2, { "gzip", "-dq", NULL }, 1 }, | |
| 25 | #if 0 | |
| 26 | /* XXX pcat does not work, cause I don't know how to make it read stdin */ | |
| 27 | { "\037\036", 2, { "pcat", NULL, NULL }, 0 }, | |
| 28 | #endif | |
| 29 | }; | |
| 30 | ||
| 31 | static int ncompr = sizeof(compr) / sizeof(compr[0]); | |
| 32 | ||
| 33 | ||
| 34 | static int uncompress __P((int, const unsigned char *, unsigned char **, int)); | |
| 35 | ||
| 36 | int | |
| 37 | zmagic(buf, nbytes) | |
| 38 | unsigned char *buf; | |
| 39 | int nbytes; | |
| 40 | { | |
| 41 | unsigned char *newbuf; | |
| 42 | int newsize; | |
| 43 | int i; | |
| 44 | ||
| 45 | for (i = 0; i < ncompr; i++) { | |
| 46 | if (nbytes < compr[i].maglen) | |
| 47 | continue; | |
| 48 | if (memcmp(buf, compr[i].magic, compr[i].maglen) == 0) | |
| 49 | break; | |
| 50 | } | |
| 51 | ||
| 52 | if (i == ncompr) | |
| 53 | return 0; | |
| 54 | ||
| 55 | if ((newsize = uncompress(i, buf, &newbuf, nbytes)) != 0) { | |
| 56 | tryit(newbuf, newsize, 1); | |
| 57 | free(newbuf); | |
| 58 | printf(" ("); | |
| 59 | tryit(buf, nbytes, 0); | |
| 60 | printf(")"); | |
| 61 | } | |
| 62 | return 1; | |
| 63 | } | |
| 64 | ||
| 65 | ||
| 66 | static int | |
| 67 | uncompress(method, old, newch, n) | |
| 68 | int method; | |
| 69 | const unsigned char *old; | |
| 70 | unsigned char **newch; | |
| 71 | int n; | |
| 72 | { | |
| 73 | int fdin[2], fdout[2]; | |
| 74 | ||
| 75 | if (pipe(fdin) == -1 || pipe(fdout) == -1) { | |
| 76 | error("cannot create pipe (%s).\n", strerror(errno)); | |
| 77 | /*NOTREACHED*/ | |
| 78 | } | |
| 79 | switch (fork()) { | |
| 80 | case 0: /* child */ | |
| 81 | (void) close(0); | |
| 82 | (void) dup(fdin[0]); | |
| 83 | (void) close(fdin[0]); | |
| 84 | (void) close(fdin[1]); | |
| 85 | ||
| 86 | (void) close(1); | |
| 87 | (void) dup(fdout[1]); | |
| 88 | (void) close(fdout[0]); | |
| 89 | (void) close(fdout[1]); | |
| 90 | if (compr[method].silent) | |
| 91 | (void) close(2); | |
| 92 | ||
| 93 | execvp(compr[method].argv[0], compr[method].argv); | |
| 94 | error("could not execute `%s' (%s).\n", | |
| 95 | compr[method].argv[0], strerror(errno)); | |
| 96 | /*NOTREACHED*/ | |
| 97 | case -1: | |
| 98 | error("could not fork (%s).\n", strerror(errno)); | |
| 99 | /*NOTREACHED*/ | |
| 100 | ||
| 101 | default: /* parent */ | |
| 102 | (void) close(fdin[0]); | |
| 103 | (void) close(fdout[1]); | |
| 104 | if (write(fdin[1], old, n) != n) { | |
| 105 | error("write failed (%s).\n", strerror(errno)); | |
| 106 | /*NOTREACHED*/ | |
| 107 | } | |
| 108 | (void) close(fdin[1]); | |
| 109 | if ((*newch = (unsigned char *) malloc(n)) == NULL) { | |
| 110 | error("out of memory.\n"); | |
| 111 | /*NOTREACHED*/ | |
| 112 | } | |
| 113 | if ((n = read(fdout[0], *newch, n)) <= 0) { | |
| 114 | free(*newch); | |
| 115 | error("read failed (%s).\n", strerror(errno)); | |
| 116 | /*NOTREACHED*/ | |
| 117 | } | |
| 118 | (void) close(fdout[0]); | |
| 119 | (void) wait(NULL); | |
| 120 | return n; | |
| 121 | } | |
| 122 | } | |
| 123 | ||
| 124 |