Root/usr/gen_init_cpio.c

1#include <stdio.h>
2#include <stdlib.h>
3#include <sys/types.h>
4#include <sys/stat.h>
5#include <string.h>
6#include <unistd.h>
7#include <time.h>
8#include <fcntl.h>
9#include <errno.h>
10#include <ctype.h>
11#include <limits.h>
12
13/*
14 * Original work by Jeff Garzik
15 *
16 * External file lists, symlink, pipe and fifo support by Thayne Harbaugh
17 * Hard link support by Luciano Rocha
18 */
19
20#define xstr(s) #s
21#define str(s) xstr(s)
22
23static unsigned int offset;
24static unsigned int ino = 721;
25static time_t default_mtime;
26
27struct file_handler {
28    const char *type;
29    int (*handler)(const char *line);
30};
31
32static void push_string(const char *name)
33{
34    unsigned int name_len = strlen(name) + 1;
35
36    fputs(name, stdout);
37    putchar(0);
38    offset += name_len;
39}
40
41static void push_pad (void)
42{
43    while (offset & 3) {
44        putchar(0);
45        offset++;
46    }
47}
48
49static void push_rest(const char *name)
50{
51    unsigned int name_len = strlen(name) + 1;
52    unsigned int tmp_ofs;
53
54    fputs(name, stdout);
55    putchar(0);
56    offset += name_len;
57
58    tmp_ofs = name_len + 110;
59    while (tmp_ofs & 3) {
60        putchar(0);
61        offset++;
62        tmp_ofs++;
63    }
64}
65
66static void push_hdr(const char *s)
67{
68    fputs(s, stdout);
69    offset += 110;
70}
71
72static void cpio_trailer(void)
73{
74    char s[256];
75    const char name[] = "TRAILER!!!";
76
77    sprintf(s, "%s%08X%08X%08lX%08lX%08X%08lX"
78           "%08X%08X%08X%08X%08X%08X%08X",
79        "070701", /* magic */
80        0, /* ino */
81        0, /* mode */
82        (long) 0, /* uid */
83        (long) 0, /* gid */
84        1, /* nlink */
85        (long) 0, /* mtime */
86        0, /* filesize */
87        0, /* major */
88        0, /* minor */
89        0, /* rmajor */
90        0, /* rminor */
91        (unsigned)strlen(name)+1, /* namesize */
92        0); /* chksum */
93    push_hdr(s);
94    push_rest(name);
95
96    while (offset % 512) {
97        putchar(0);
98        offset++;
99    }
100}
101
102static int cpio_mkslink(const char *name, const char *target,
103             unsigned int mode, uid_t uid, gid_t gid)
104{
105    char s[256];
106
107    if (name[0] == '/')
108        name++;
109    sprintf(s,"%s%08X%08X%08lX%08lX%08X%08lX"
110           "%08X%08X%08X%08X%08X%08X%08X",
111        "070701", /* magic */
112        ino++, /* ino */
113        S_IFLNK | mode, /* mode */
114        (long) uid, /* uid */
115        (long) gid, /* gid */
116        1, /* nlink */
117        (long) default_mtime, /* mtime */
118        (unsigned)strlen(target)+1, /* filesize */
119        3, /* major */
120        1, /* minor */
121        0, /* rmajor */
122        0, /* rminor */
123        (unsigned)strlen(name) + 1,/* namesize */
124        0); /* chksum */
125    push_hdr(s);
126    push_string(name);
127    push_pad();
128    push_string(target);
129    push_pad();
130    return 0;
131}
132
133static int cpio_mkslink_line(const char *line)
134{
135    char name[PATH_MAX + 1];
136    char target[PATH_MAX + 1];
137    unsigned int mode;
138    int uid;
139    int gid;
140    int rc = -1;
141
142    if (5 != sscanf(line, "%" str(PATH_MAX) "s %" str(PATH_MAX) "s %o %d %d", name, target, &mode, &uid, &gid)) {
143        fprintf(stderr, "Unrecognized dir format '%s'", line);
144        goto fail;
145    }
146    rc = cpio_mkslink(name, target, mode, uid, gid);
147 fail:
148    return rc;
149}
150
151static int cpio_mkgeneric(const char *name, unsigned int mode,
152               uid_t uid, gid_t gid)
153{
154    char s[256];
155
156    if (name[0] == '/')
157        name++;
158    sprintf(s,"%s%08X%08X%08lX%08lX%08X%08lX"
159           "%08X%08X%08X%08X%08X%08X%08X",
160        "070701", /* magic */
161        ino++, /* ino */
162        mode, /* mode */
163        (long) uid, /* uid */
164        (long) gid, /* gid */
165        2, /* nlink */
166        (long) default_mtime, /* mtime */
167        0, /* filesize */
168        3, /* major */
169        1, /* minor */
170        0, /* rmajor */
171        0, /* rminor */
172        (unsigned)strlen(name) + 1,/* namesize */
173        0); /* chksum */
174    push_hdr(s);
175    push_rest(name);
176    return 0;
177}
178
179enum generic_types {
180    GT_DIR,
181    GT_PIPE,
182    GT_SOCK
183};
184
185struct generic_type {
186    const char *type;
187    mode_t mode;
188};
189
190static struct generic_type generic_type_table[] = {
191    [GT_DIR] = {
192        .type = "dir",
193        .mode = S_IFDIR
194    },
195    [GT_PIPE] = {
196        .type = "pipe",
197        .mode = S_IFIFO
198    },
199    [GT_SOCK] = {
200        .type = "sock",
201        .mode = S_IFSOCK
202    }
203};
204
205static int cpio_mkgeneric_line(const char *line, enum generic_types gt)
206{
207    char name[PATH_MAX + 1];
208    unsigned int mode;
209    int uid;
210    int gid;
211    int rc = -1;
212
213    if (4 != sscanf(line, "%" str(PATH_MAX) "s %o %d %d", name, &mode, &uid, &gid)) {
214        fprintf(stderr, "Unrecognized %s format '%s'",
215            line, generic_type_table[gt].type);
216        goto fail;
217    }
218    mode |= generic_type_table[gt].mode;
219    rc = cpio_mkgeneric(name, mode, uid, gid);
220 fail:
221    return rc;
222}
223
224static int cpio_mkdir_line(const char *line)
225{
226    return cpio_mkgeneric_line(line, GT_DIR);
227}
228
229static int cpio_mkpipe_line(const char *line)
230{
231    return cpio_mkgeneric_line(line, GT_PIPE);
232}
233
234static int cpio_mksock_line(const char *line)
235{
236    return cpio_mkgeneric_line(line, GT_SOCK);
237}
238
239static int cpio_mknod(const char *name, unsigned int mode,
240               uid_t uid, gid_t gid, char dev_type,
241               unsigned int maj, unsigned int min)
242{
243    char s[256];
244
245    if (dev_type == 'b')
246        mode |= S_IFBLK;
247    else
248        mode |= S_IFCHR;
249
250    if (name[0] == '/')
251        name++;
252    sprintf(s,"%s%08X%08X%08lX%08lX%08X%08lX"
253           "%08X%08X%08X%08X%08X%08X%08X",
254        "070701", /* magic */
255        ino++, /* ino */
256        mode, /* mode */
257        (long) uid, /* uid */
258        (long) gid, /* gid */
259        1, /* nlink */
260        (long) default_mtime, /* mtime */
261        0, /* filesize */
262        3, /* major */
263        1, /* minor */
264        maj, /* rmajor */
265        min, /* rminor */
266        (unsigned)strlen(name) + 1,/* namesize */
267        0); /* chksum */
268    push_hdr(s);
269    push_rest(name);
270    return 0;
271}
272
273static int cpio_mknod_line(const char *line)
274{
275    char name[PATH_MAX + 1];
276    unsigned int mode;
277    int uid;
278    int gid;
279    char dev_type;
280    unsigned int maj;
281    unsigned int min;
282    int rc = -1;
283
284    if (7 != sscanf(line, "%" str(PATH_MAX) "s %o %d %d %c %u %u",
285             name, &mode, &uid, &gid, &dev_type, &maj, &min)) {
286        fprintf(stderr, "Unrecognized nod format '%s'", line);
287        goto fail;
288    }
289    rc = cpio_mknod(name, mode, uid, gid, dev_type, maj, min);
290 fail:
291    return rc;
292}
293
294static int cpio_mkfile(const char *name, const char *location,
295            unsigned int mode, uid_t uid, gid_t gid,
296            unsigned int nlinks)
297{
298    char s[256];
299    char *filebuf = NULL;
300    struct stat buf;
301    long size;
302    int file = -1;
303    int retval;
304    int rc = -1;
305    int namesize;
306    unsigned int i;
307
308    mode |= S_IFREG;
309
310    file = open (location, O_RDONLY);
311    if (file < 0) {
312        fprintf (stderr, "File %s could not be opened for reading\n", location);
313        goto error;
314    }
315
316    retval = fstat(file, &buf);
317    if (retval) {
318        fprintf(stderr, "File %s could not be stat()'ed\n", location);
319        goto error;
320    }
321
322    filebuf = malloc(buf.st_size);
323    if (!filebuf) {
324        fprintf (stderr, "out of memory\n");
325        goto error;
326    }
327
328    retval = read (file, filebuf, buf.st_size);
329    if (retval < 0) {
330        fprintf (stderr, "Can not read %s file\n", location);
331        goto error;
332    }
333
334    size = 0;
335    for (i = 1; i <= nlinks; i++) {
336        /* data goes on last link */
337        if (i == nlinks) size = buf.st_size;
338
339        if (name[0] == '/')
340            name++;
341        namesize = strlen(name) + 1;
342        sprintf(s,"%s%08X%08X%08lX%08lX%08X%08lX"
343               "%08lX%08X%08X%08X%08X%08X%08X",
344            "070701", /* magic */
345            ino, /* ino */
346            mode, /* mode */
347            (long) uid, /* uid */
348            (long) gid, /* gid */
349            nlinks, /* nlink */
350            (long) buf.st_mtime, /* mtime */
351            size, /* filesize */
352            3, /* major */
353            1, /* minor */
354            0, /* rmajor */
355            0, /* rminor */
356            namesize, /* namesize */
357            0); /* chksum */
358        push_hdr(s);
359        push_string(name);
360        push_pad();
361
362        if (size) {
363            if (fwrite(filebuf, size, 1, stdout) != 1) {
364                fprintf(stderr, "writing filebuf failed\n");
365                goto error;
366            }
367            offset += size;
368            push_pad();
369        }
370
371        name += namesize;
372    }
373    ino++;
374    rc = 0;
375    
376error:
377    if (filebuf) free(filebuf);
378    if (file >= 0) close(file);
379    return rc;
380}
381
382static char *cpio_replace_env(char *new_location)
383{
384    char expanded[PATH_MAX + 1];
385    char env_var[PATH_MAX + 1];
386    char *start;
387    char *end;
388
389    for (start = NULL; (start = strstr(new_location, "${")); ) {
390        end = strchr(start, '}');
391        if (start < end) {
392            *env_var = *expanded = '\0';
393            strncat(env_var, start + 2, end - start - 2);
394            strncat(expanded, new_location, start - new_location);
395            strncat(expanded, getenv(env_var),
396                PATH_MAX - strlen(expanded));
397            strncat(expanded, end + 1,
398                PATH_MAX - strlen(expanded));
399            strncpy(new_location, expanded, PATH_MAX);
400            new_location[PATH_MAX] = 0;
401        } else
402            break;
403    }
404
405    return new_location;
406}
407
408static int cpio_mkfile_line(const char *line)
409{
410    char name[PATH_MAX + 1];
411    char *dname = NULL; /* malloc'ed buffer for hard links */
412    char location[PATH_MAX + 1];
413    unsigned int mode;
414    int uid;
415    int gid;
416    int nlinks = 1;
417    int end = 0, dname_len = 0;
418    int rc = -1;
419
420    if (5 > sscanf(line, "%" str(PATH_MAX) "s %" str(PATH_MAX)
421                "s %o %d %d %n",
422                name, location, &mode, &uid, &gid, &end)) {
423        fprintf(stderr, "Unrecognized file format '%s'", line);
424        goto fail;
425    }
426    if (end && isgraph(line[end])) {
427        int len;
428        int nend;
429
430        dname = malloc(strlen(line));
431        if (!dname) {
432            fprintf (stderr, "out of memory (%d)\n", dname_len);
433            goto fail;
434        }
435
436        dname_len = strlen(name) + 1;
437        memcpy(dname, name, dname_len);
438
439        do {
440            nend = 0;
441            if (sscanf(line + end, "%" str(PATH_MAX) "s %n",
442                    name, &nend) < 1)
443                break;
444            len = strlen(name) + 1;
445            memcpy(dname + dname_len, name, len);
446            dname_len += len;
447            nlinks++;
448            end += nend;
449        } while (isgraph(line[end]));
450    } else {
451        dname = name;
452    }
453    rc = cpio_mkfile(dname, cpio_replace_env(location),
454                     mode, uid, gid, nlinks);
455 fail:
456    if (dname_len) free(dname);
457    return rc;
458}
459
460static void usage(const char *prog)
461{
462    fprintf(stderr, "Usage:\n"
463        "\t%s [-t <timestamp>] <cpio_list>\n"
464        "\n"
465        "<cpio_list> is a file containing newline separated entries that\n"
466        "describe the files to be included in the initramfs archive:\n"
467        "\n"
468        "# a comment\n"
469        "file <name> <location> <mode> <uid> <gid> [<hard links>]\n"
470        "dir <name> <mode> <uid> <gid>\n"
471        "nod <name> <mode> <uid> <gid> <dev_type> <maj> <min>\n"
472        "slink <name> <target> <mode> <uid> <gid>\n"
473        "pipe <name> <mode> <uid> <gid>\n"
474        "sock <name> <mode> <uid> <gid>\n"
475        "\n"
476        "<name> name of the file/dir/nod/etc in the archive\n"
477        "<location> location of the file in the current filesystem\n"
478        " expands shell variables quoted with ${}\n"
479        "<target> link target\n"
480        "<mode> mode/permissions of the file\n"
481        "<uid> user id (0=root)\n"
482        "<gid> group id (0=root)\n"
483        "<dev_type> device type (b=block, c=character)\n"
484        "<maj> major number of nod\n"
485        "<min> minor number of nod\n"
486        "<hard links> space separated list of other links to file\n"
487        "\n"
488        "example:\n"
489        "# A simple initramfs\n"
490        "dir /dev 0755 0 0\n"
491        "nod /dev/console 0600 0 0 c 5 1\n"
492        "dir /root 0700 0 0\n"
493        "dir /sbin 0755 0 0\n"
494        "file /sbin/kinit /usr/src/klibc/kinit/kinit 0755 0 0\n"
495        "\n"
496        "<timestamp> is time in seconds since Epoch that will be used\n"
497        "as mtime for symlinks, special files and directories. The default\n"
498        "is to use the current time for these entries.\n",
499        prog);
500}
501
502struct file_handler file_handler_table[] = {
503    {
504        .type = "file",
505        .handler = cpio_mkfile_line,
506    }, {
507        .type = "nod",
508        .handler = cpio_mknod_line,
509    }, {
510        .type = "dir",
511        .handler = cpio_mkdir_line,
512    }, {
513        .type = "slink",
514        .handler = cpio_mkslink_line,
515    }, {
516        .type = "pipe",
517        .handler = cpio_mkpipe_line,
518    }, {
519        .type = "sock",
520        .handler = cpio_mksock_line,
521    }, {
522        .type = NULL,
523        .handler = NULL,
524    }
525};
526
527#define LINE_SIZE (2 * PATH_MAX + 50)
528
529int main (int argc, char *argv[])
530{
531    FILE *cpio_list;
532    char line[LINE_SIZE];
533    char *args, *type;
534    int ec = 0;
535    int line_nr = 0;
536    const char *filename;
537
538    default_mtime = time(NULL);
539    while (1) {
540        int opt = getopt(argc, argv, "t:h");
541        char *invalid;
542
543        if (opt == -1)
544            break;
545        switch (opt) {
546        case 't':
547            default_mtime = strtol(optarg, &invalid, 10);
548            if (!*optarg || *invalid) {
549                fprintf(stderr, "Invalid timestamp: %s\n",
550                        optarg);
551                usage(argv[0]);
552                exit(1);
553            }
554            break;
555        case 'h':
556        case '?':
557            usage(argv[0]);
558            exit(opt == 'h' ? 0 : 1);
559        }
560    }
561
562    if (argc - optind != 1) {
563        usage(argv[0]);
564        exit(1);
565    }
566    filename = argv[optind];
567    if (!strcmp(filename, "-"))
568        cpio_list = stdin;
569    else if (!(cpio_list = fopen(filename, "r"))) {
570        fprintf(stderr, "ERROR: unable to open '%s': %s\n\n",
571            filename, strerror(errno));
572        usage(argv[0]);
573        exit(1);
574    }
575
576    while (fgets(line, LINE_SIZE, cpio_list)) {
577        int type_idx;
578        size_t slen = strlen(line);
579
580        line_nr++;
581
582        if ('#' == *line) {
583            /* comment - skip to next line */
584            continue;
585        }
586
587        if (! (type = strtok(line, " \t"))) {
588            fprintf(stderr,
589                "ERROR: incorrect format, could not locate file type line %d: '%s'\n",
590                line_nr, line);
591            ec = -1;
592            break;
593        }
594
595        if ('\n' == *type) {
596            /* a blank line */
597            continue;
598        }
599
600        if (slen == strlen(type)) {
601            /* must be an empty line */
602            continue;
603        }
604
605        if (! (args = strtok(NULL, "\n"))) {
606            fprintf(stderr,
607                "ERROR: incorrect format, newline required line %d: '%s'\n",
608                line_nr, line);
609            ec = -1;
610        }
611
612        for (type_idx = 0; file_handler_table[type_idx].type; type_idx++) {
613            int rc;
614            if (! strcmp(line, file_handler_table[type_idx].type)) {
615                if ((rc = file_handler_table[type_idx].handler(args))) {
616                    ec = rc;
617                    fprintf(stderr, " line %d\n", line_nr);
618                }
619                break;
620            }
621        }
622
623        if (NULL == file_handler_table[type_idx].type) {
624            fprintf(stderr, "unknown file type line %d: '%s'\n",
625                line_nr, line);
626        }
627    }
628    if (ec == 0)
629        cpio_trailer();
630
631    exit(ec);
632}
633

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