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// SPDX-License-Identifier: MIT
/*
* declone.c - break hardlink off a file
* written by Jan Engelhardt, 2021
*/
#include <errno.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <libHX/defs.h>
#include <libHX/string.h>
#include <sys/mman.h>
#include <sys/stat.h>
#include <sys/types.h>
static void dofile(const char *file)
{
struct stat sb;
int infd = open(file, O_RDONLY);
if (infd < 0) {
fprintf(stderr, "Could not open %s: %s\n",
file, strerror(errno));
return;
}
if (fstat(infd, &sb) < 0) {
fprintf(stderr, "Could not stat %s: %s\n",
file, strerror(errno));
goto out;
}
void *inmap = mmap(NULL, sb.st_size, PROT_READ, MAP_SHARED, infd, 0);
if (inmap == MAP_FAILED) {
fprintf(stderr, "mmap %s: %s\n", file, strerror(errno));
goto out;
}
char *cont_dir = HX_dirname(file);
if (cont_dir == NULL) {
fprintf(stderr, "%s\n", strerror(errno));
goto out2;
}
hxmc_t *outname = HXmc_strinit(cont_dir);
if (outname == NULL) {
fprintf(stderr, "%s\n", strerror(errno));
goto out3;
}
if (HXmc_strcat(&outname, "/decloneXXXXXX") == NULL) {
fprintf(stderr, "%s\n", strerror(errno));
goto out4;
}
if (mkstemp(outname) < 0) {
fprintf(stderr, "mkstemp: %s\n", strerror(errno));
goto out4;
}
int outfd = open(outname, O_RDWR, S_IRUGO | S_IWUGO);
if (outfd < 0) {
fprintf(stderr, "open %s: %s\n", outname, strerror(errno));
goto out4;
}
if (ftruncate(outfd, sb.st_size) < 0) {
fprintf(stderr, "ftruncate %s: %s\n", outname, strerror(errno));
goto out5;
}
if (fchown(outfd, sb.st_uid, sb.st_gid) < 0 ||
fchmod(outfd, sb.st_mode) < 0) {
fprintf(stderr, "fchown/fchmod %s: %s\n", outname, strerror(errno));
goto out5;
}
void *outmap = mmap(NULL, sb.st_size, PROT_WRITE, MAP_SHARED, outfd, 0);
if (outmap == MAP_FAILED) {
fprintf(stderr, "mmap %s: %s\n", outname, strerror(errno));
goto out5;
}
memcpy(outmap, inmap, sb.st_size);
if (msync(outmap, sb.st_size, MS_ASYNC) < 0) {
fprintf(stderr, "msync: %s\n", strerror(errno));
goto out6;
}
if (rename(outname, file) < 0) {
fprintf(stderr, "Could not replace %s: %s\n",
file, strerror(errno));
goto out6;
}
printf("* %s\n", file);
out6:
munmap(outmap, sb.st_size);
out5:
close(outfd);
unlink(outname);
out4:
HXmc_free(outname);
out3:
free(cont_dir);
out2:
munmap(inmap, sb.st_size);
out:
close(infd);
}
int main(int argc, const char **argv)
{
++argv;
for (; --argc > 0 && *argv != NULL; ++argv)
dofile(*argv);
return EXIT_SUCCESS;
}
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