Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
gen_init_cpio: write to fd instead of stdout stream
In preparation for more efficient archiving using copy_file_range(),
switch from writing archive data to stdout to using STDOUT_FILENO and
I/O via write(), dprintf(), etc.
Basic I/O error handling is added to cover cases such as ENOSPC. Partial
writes are treated as errors.
Signed-off-by: David Disseldorp <ddiss@suse.de>
Reviewed-by: Nicolas Schier <nsc@kernel.org>
Link: https://lore.kernel.org/r/20250819032607.28727-2-ddiss@suse.de
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
authored by
David Disseldorp
and committed by
Nathan Chancellor
14002277
75a6b459
+81
-58
+81
-58
usr/gen_init_cpio.c
+81
-58
usr/gen_init_cpio.c
···
23
23
#define xstr(s) #s
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#define str(s) xstr(s)
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#define MIN(a, b) ((a) < (b) ? (a) : (b))
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+
#define CPIO_HDR_LEN 110
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#define padlen(_off, _align) (((_align) - ((_off) & ((_align) - 1))) % (_align))
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+
static char padding[512];
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static unsigned int offset;
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static unsigned int ino = 721;
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static time_t default_mtime;
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static bool do_file_mtime;
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static bool do_csum = false;
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static int outfd = STDOUT_FILENO;
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struct file_handler {
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const char *type;
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int (*handler)(const char *line);
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};
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-
static void push_string(const char *name)
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static int push_string(const char *name)
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{
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unsigned int name_len = strlen(name) + 1;
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ssize_t len;
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fputs(name, stdout);
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putchar(0);
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len = write(outfd, name, name_len);
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if (len != name_len)
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return -1;
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+
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offset += name_len;
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return 0;
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}
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-
static void push_pad (void)
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static int push_pad(size_t padlen)
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{
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-
while (offset & 3) {
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-
putchar(0);
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-
offset++;
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-
}
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+
ssize_t len = 0;
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+
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+
if (!padlen)
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return 0;
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+
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+
if (padlen < sizeof(padding))
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len = write(outfd, padding, padlen);
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if (len != padlen)
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return -1;
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+
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offset += padlen;
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return 0;
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}
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-
static void push_rest(const char *name)
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static int push_rest(const char *name)
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{
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unsigned int name_len = strlen(name) + 1;
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-
unsigned int tmp_ofs;
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ssize_t len;
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-
fputs(name, stdout);
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-
putchar(0);
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len = write(outfd, name, name_len);
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if (len != name_len)
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return -1;
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+
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offset += name_len;
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-
tmp_ofs = name_len + 110;
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-
while (tmp_ofs & 3) {
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-
putchar(0);
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offset++;
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tmp_ofs++;
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-
}
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+
return push_pad(padlen(name_len + CPIO_HDR_LEN, 4));
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}
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-
static void push_hdr(const char *s)
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static int cpio_trailer(void)
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{
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fputs(s, stdout);
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offset += 110;
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-
}
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-
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-
static void cpio_trailer(void)
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{
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char s[256];
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const char name[] = "TRAILER!!!";
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int len;
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-
sprintf(s, "%s%08X%08X%08lX%08lX%08X%08lX"
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len = dprintf(outfd, "%s%08X%08X%08lX%08lX%08X%08lX"
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"%08X%08X%08X%08X%08X%08X%08X",
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do_csum ? "070702" : "070701", /* magic */
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0, /* ino */
···
103
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0, /* rminor */
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(unsigned)strlen(name)+1, /* namesize */
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0); /* chksum */
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-
push_hdr(s);
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-
push_rest(name);
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offset += len;
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-
while (offset % 512) {
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-
putchar(0);
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-
offset++;
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-
}
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+
if (len != CPIO_HDR_LEN ||
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+
push_rest(name) < 0 ||
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+
push_pad(padlen(offset, 512)) < 0)
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+
return -1;
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+
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+
return 0;
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}
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static int cpio_mkslink(const char *name, const char *target,
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unsigned int mode, uid_t uid, gid_t gid)
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{
118
-
char s[256];
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+
int len;
119
113
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if (name[0] == '/')
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name++;
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-
sprintf(s,"%s%08X%08X%08lX%08lX%08X%08lX"
116
+
len = dprintf(outfd, "%s%08X%08X%08lX%08lX%08X%08lX"
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"%08X%08X%08X%08X%08X%08X%08X",
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118
do_csum ? "070702" : "070701", /* magic */
125
119
ino++, /* ino */
···
136
128
0, /* rminor */
137
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(unsigned)strlen(name) + 1,/* namesize */
138
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0); /* chksum */
139
-
push_hdr(s);
140
-
push_string(name);
141
-
push_pad();
142
-
push_string(target);
143
-
push_pad();
131
+
offset += len;
132
+
133
+
if (len != CPIO_HDR_LEN ||
134
+
push_string(name) < 0 ||
135
+
push_pad(padlen(offset, 4)) < 0 ||
136
+
push_string(target) < 0 ||
137
+
push_pad(padlen(offset, 4)) < 0)
138
+
return -1;
139
+
144
140
return 0;
141
+
145
142
}
146
143
147
144
static int cpio_mkslink_line(const char *line)
···
170
157
static int cpio_mkgeneric(const char *name, unsigned int mode,
171
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uid_t uid, gid_t gid)
172
159
{
173
-
char s[256];
160
+
int len;
174
161
175
162
if (name[0] == '/')
176
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name++;
177
-
sprintf(s,"%s%08X%08X%08lX%08lX%08X%08lX"
164
+
len = dprintf(outfd, "%s%08X%08X%08lX%08lX%08X%08lX"
178
165
"%08X%08X%08X%08X%08X%08X%08X",
179
166
do_csum ? "070702" : "070701", /* magic */
180
167
ino++, /* ino */
···
190
177
0, /* rminor */
191
178
(unsigned)strlen(name) + 1,/* namesize */
192
179
0); /* chksum */
193
-
push_hdr(s);
194
-
push_rest(name);
180
+
offset += len;
181
+
182
+
if (len != CPIO_HDR_LEN ||
183
+
push_rest(name) < 0)
184
+
return -1;
185
+
195
186
return 0;
196
187
}
197
188
···
263
246
uid_t uid, gid_t gid, char dev_type,
264
247
unsigned int maj, unsigned int min)
265
248
{
266
-
char s[256];
249
+
int len;
267
250
268
251
if (dev_type == 'b')
269
252
mode |= S_IFBLK;
···
272
255
273
256
if (name[0] == '/')
274
257
name++;
275
-
sprintf(s,"%s%08X%08X%08lX%08lX%08X%08lX"
258
+
len = dprintf(outfd, "%s%08X%08X%08lX%08lX%08X%08lX"
276
259
"%08X%08X%08X%08X%08X%08X%08X",
277
260
do_csum ? "070702" : "070701", /* magic */
278
261
ino++, /* ino */
···
288
271
min, /* rminor */
289
272
(unsigned)strlen(name) + 1,/* namesize */
290
273
0); /* chksum */
291
-
push_hdr(s);
292
-
push_rest(name);
274
+
offset += len;
275
+
276
+
if (len != CPIO_HDR_LEN ||
277
+
push_rest(name) < 0)
278
+
return -1;
279
+
293
280
return 0;
294
281
}
295
282
···
345
324
unsigned int mode, uid_t uid, gid_t gid,
346
325
unsigned int nlinks)
347
326
{
348
-
char s[256];
349
327
struct stat buf;
350
328
unsigned long size;
351
-
int file;
352
-
int retval;
329
+
int file, retval, len;
353
330
int rc = -1;
354
331
time_t mtime;
355
332
int namesize;
···
405
386
if (name[0] == '/')
406
387
name++;
407
388
namesize = strlen(name) + 1;
408
-
sprintf(s,"%s%08X%08X%08lX%08lX%08X%08lX"
389
+
len = dprintf(outfd, "%s%08X%08X%08lX%08lX%08X%08lX"
409
390
"%08lX%08X%08X%08X%08X%08X%08X",
410
391
do_csum ? "070702" : "070701", /* magic */
411
392
ino, /* ino */
···
421
402
0, /* rminor */
422
403
namesize, /* namesize */
423
404
size ? csum : 0); /* chksum */
424
-
push_hdr(s);
425
-
push_string(name);
426
-
push_pad();
405
+
offset += len;
406
+
407
+
if (len != CPIO_HDR_LEN ||
408
+
push_string(name) < 0 ||
409
+
push_pad(padlen(offset, 4)) < 0)
410
+
goto error;
427
411
428
412
while (size) {
429
413
unsigned char filebuf[65536];
···
439
417
goto error;
440
418
}
441
419
442
-
if (fwrite(filebuf, this_read, 1, stdout) != 1) {
420
+
if (write(outfd, filebuf, this_read) != this_read) {
443
421
fprintf(stderr, "writing filebuf failed\n");
444
422
goto error;
445
423
}
446
424
offset += this_read;
447
425
size -= this_read;
448
426
}
449
-
push_pad();
427
+
if (push_pad(padlen(offset, 4)) < 0)
428
+
goto error;
450
429
451
430
name += namesize;
452
431
}
···
714
691
}
715
692
}
716
693
if (ec == 0)
717
-
cpio_trailer();
694
+
ec = cpio_trailer();
718
695
719
696
exit(ec);
720
697
}