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 *start, *end, *var;
386
387    while ((start = strstr(new_location, "${")) &&
388           (end = strchr(start + 2, '}'))) {
389        *start = *end = 0;
390        var = getenv(start + 2);
391        snprintf(expanded, sizeof expanded, "%s%s%s",
392             new_location, var ? var : "", end + 1);
393        strcpy(new_location, expanded);
394    }
395
396    return new_location;
397}
398
399static int cpio_mkfile_line(const char *line)
400{
401    char name[PATH_MAX + 1];
402    char *dname = NULL; /* malloc'ed buffer for hard links */
403    char location[PATH_MAX + 1];
404    unsigned int mode;
405    int uid;
406    int gid;
407    int nlinks = 1;
408    int end = 0, dname_len = 0;
409    int rc = -1;
410
411    if (5 > sscanf(line, "%" str(PATH_MAX) "s %" str(PATH_MAX)
412                "s %o %d %d %n",
413                name, location, &mode, &uid, &gid, &end)) {
414        fprintf(stderr, "Unrecognized file format '%s'", line);
415        goto fail;
416    }
417    if (end && isgraph(line[end])) {
418        int len;
419        int nend;
420
421        dname = malloc(strlen(line));
422        if (!dname) {
423            fprintf (stderr, "out of memory (%d)\n", dname_len);
424            goto fail;
425        }
426
427        dname_len = strlen(name) + 1;
428        memcpy(dname, name, dname_len);
429
430        do {
431            nend = 0;
432            if (sscanf(line + end, "%" str(PATH_MAX) "s %n",
433                    name, &nend) < 1)
434                break;
435            len = strlen(name) + 1;
436            memcpy(dname + dname_len, name, len);
437            dname_len += len;
438            nlinks++;
439            end += nend;
440        } while (isgraph(line[end]));
441    } else {
442        dname = name;
443    }
444    rc = cpio_mkfile(dname, cpio_replace_env(location),
445                     mode, uid, gid, nlinks);
446 fail:
447    if (dname_len) free(dname);
448    return rc;
449}
450
451static void usage(const char *prog)
452{
453    fprintf(stderr, "Usage:\n"
454        "\t%s [-t <timestamp>] <cpio_list>\n"
455        "\n"
456        "<cpio_list> is a file containing newline separated entries that\n"
457        "describe the files to be included in the initramfs archive:\n"
458        "\n"
459        "# a comment\n"
460        "file <name> <location> <mode> <uid> <gid> [<hard links>]\n"
461        "dir <name> <mode> <uid> <gid>\n"
462        "nod <name> <mode> <uid> <gid> <dev_type> <maj> <min>\n"
463        "slink <name> <target> <mode> <uid> <gid>\n"
464        "pipe <name> <mode> <uid> <gid>\n"
465        "sock <name> <mode> <uid> <gid>\n"
466        "\n"
467        "<name> name of the file/dir/nod/etc in the archive\n"
468        "<location> location of the file in the current filesystem\n"
469        " expands shell variables quoted with ${}\n"
470        "<target> link target\n"
471        "<mode> mode/permissions of the file\n"
472        "<uid> user id (0=root)\n"
473        "<gid> group id (0=root)\n"
474        "<dev_type> device type (b=block, c=character)\n"
475        "<maj> major number of nod\n"
476        "<min> minor number of nod\n"
477        "<hard links> space separated list of other links to file\n"
478        "\n"
479        "example:\n"
480        "# A simple initramfs\n"
481        "dir /dev 0755 0 0\n"
482        "nod /dev/console 0600 0 0 c 5 1\n"
483        "dir /root 0700 0 0\n"
484        "dir /sbin 0755 0 0\n"
485        "file /sbin/kinit /usr/src/klibc/kinit/kinit 0755 0 0\n"
486        "\n"
487        "<timestamp> is time in seconds since Epoch that will be used\n"
488        "as mtime for symlinks, special files and directories. The default\n"
489        "is to use the current time for these entries.\n",
490        prog);
491}
492
493struct file_handler file_handler_table[] = {
494    {
495        .type = "file",
496        .handler = cpio_mkfile_line,
497    }, {
498        .type = "nod",
499        .handler = cpio_mknod_line,
500    }, {
501        .type = "dir",
502        .handler = cpio_mkdir_line,
503    }, {
504        .type = "slink",
505        .handler = cpio_mkslink_line,
506    }, {
507        .type = "pipe",
508        .handler = cpio_mkpipe_line,
509    }, {
510        .type = "sock",
511        .handler = cpio_mksock_line,
512    }, {
513        .type = NULL,
514        .handler = NULL,
515    }
516};
517
518#define LINE_SIZE (2 * PATH_MAX + 50)
519
520int main (int argc, char *argv[])
521{
522    FILE *cpio_list;
523    char line[LINE_SIZE];
524    char *args, *type;
525    int ec = 0;
526    int line_nr = 0;
527    const char *filename;
528
529    default_mtime = time(NULL);
530    while (1) {
531        int opt = getopt(argc, argv, "t:h");
532        char *invalid;
533
534        if (opt == -1)
535            break;
536        switch (opt) {
537        case 't':
538            default_mtime = strtol(optarg, &invalid, 10);
539            if (!*optarg || *invalid) {
540                fprintf(stderr, "Invalid timestamp: %s\n",
541                        optarg);
542                usage(argv[0]);
543                exit(1);
544            }
545            break;
546        case 'h':
547        case '?':
548            usage(argv[0]);
549            exit(opt == 'h' ? 0 : 1);
550        }
551    }
552
553    if (argc - optind != 1) {
554        usage(argv[0]);
555        exit(1);
556    }
557    filename = argv[optind];
558    if (!strcmp(filename, "-"))
559        cpio_list = stdin;
560    else if (!(cpio_list = fopen(filename, "r"))) {
561        fprintf(stderr, "ERROR: unable to open '%s': %s\n\n",
562            filename, strerror(errno));
563        usage(argv[0]);
564        exit(1);
565    }
566
567    while (fgets(line, LINE_SIZE, cpio_list)) {
568        int type_idx;
569        size_t slen = strlen(line);
570
571        line_nr++;
572
573        if ('#' == *line) {
574            /* comment - skip to next line */
575            continue;
576        }
577
578        if (! (type = strtok(line, " \t"))) {
579            fprintf(stderr,
580                "ERROR: incorrect format, could not locate file type line %d: '%s'\n",
581                line_nr, line);
582            ec = -1;
583            break;
584        }
585
586        if ('\n' == *type) {
587            /* a blank line */
588            continue;
589        }
590
591        if (slen == strlen(type)) {
592            /* must be an empty line */
593            continue;
594        }
595
596        if (! (args = strtok(NULL, "\n"))) {
597            fprintf(stderr,
598                "ERROR: incorrect format, newline required line %d: '%s'\n",
599                line_nr, line);
600            ec = -1;
601        }
602
603        for (type_idx = 0; file_handler_table[type_idx].type; type_idx++) {
604            int rc;
605            if (! strcmp(line, file_handler_table[type_idx].type)) {
606                if ((rc = file_handler_table[type_idx].handler(args))) {
607                    ec = rc;
608                    fprintf(stderr, " line %d\n", line_nr);
609                }
610                break;
611            }
612        }
613
614        if (NULL == file_handler_table[type_idx].type) {
615            fprintf(stderr, "unknown file type line %d: '%s'\n",
616                line_nr, line);
617        }
618    }
619    if (ec == 0)
620        cpio_trailer();
621
622    exit(ec);
623}
624

Archive Download this file



interactive