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#define _GNU_SOURCE /* for program_invocation_name */
#include <assert.h> /* for assert(3p) */
#include <errno.h> /* for errno, program_invocation_name */
#include <error.h> /* for error(3gnu) */
#include <fcntl.h> /* for O_RDONLY, O_RDWR */
#include <getopt.h> /* for getopt_long(3gnu), struct option, optind */
#include <stdbool.h> /* for bool, true, false */
#include <stdint.h> /* for uint64_t */
#include <stdio.h> /* for printf(3gnu), fprintf(3p), stderr */
#include <stdlib.h> /* for strtoll(3p), calloc(3p), free(3p), exit(3p), EXIT_SUCCESS */
#include <string.h> /* for strlen(3p) */
#include <unistd.h> /* for dup2(3p) */
#include "dedupe-range.h" /* for dedupe_range, struct range */
#define EXIT_INVALIDARGUMENT 2
#define errusage(format, ...) do { \
error(0, 0, format, ## __VA_ARGS__); \
fprintf(stderr, "Try '%s --help' for more information.\n", program_invocation_name); \
exit(EXIT_INVALIDARGUMENT); \
} while(0)
bool atou64(const char *str, uint64_t *ret) {
assert(sizeof(uint64_t) <= sizeof(unsigned long long int));
if (!('0' <= str[0] && str[0] <= '9'))
return false;
errno = 0;
char *end;
unsigned long long int n = strtoll(str, &end, 10);
if (end[0] != '\0' || errno != 0)
return false;
*ret = (uint64_t)n;
return true;
}
void usage() {
printf("Usage: %2$*1$s [OPTIONS] LENGTH SRC_FILENAME SRC_OFFSET \\\n"
" %3$*1$s DST_FILENAME DST_OFFSET \\\n"
" %3$*1$s [DST_FILENAME DST_OFFSET]...\n"
"Submit a file deduplication request to the kernel.\n"
"If the file ranges are not duplicates, the kernel will ignore this request.\n"
"\n"
"OPTIONS:\n"
" -r, --readonly Open destination files read-only, rather than read/write.\n"
" Generically, the destination must be open for writing.\n"
" However, on Btrfs, this allows deduplication to be done\n"
" on read-only subvolumes when invoked as root.\n"
" -h, --help Display this help and exit.\n",
(int)strlen(program_invocation_name), program_invocation_name, "");
}
int main(int argc, char *argv[]) {
int ro = 0;
struct option long_options[] = {
{"readonly", no_argument, &ro, 1},
{"help", no_argument, NULL, 'h'},
{0}
};
int flag;
while ((flag = getopt_long(argc, argv, "rh", long_options, NULL)) >= 0) {
switch (flag) {
case 0:
break;
case 'r':
ro = 1;
break;
case 'h':
usage();
return EXIT_SUCCESS;
case '?':
fprintf(stderr, "Try '%s --help' for more information.\n", program_invocation_name);
return EXIT_INVALIDARGUMENT;
default:
assert(false);
}
}
if (argc - optind < 5)
errusage("too few arguments");
if ((argc - optind - 1) % 2 != 0)
errusage("wrong number of arguments");
uint64_t src_length;
if (!atou64(argv[optind], &src_length))
error(2, errno, "invalid length '%s'", argv[optind]);
struct filepos src;
src.filename = argv[optind+1];
src.flags = O_RDONLY;
if (!atou64(argv[optind+2], &src.offset))
error(2, errno, "invalid offset '%s'", argv[optind+2]);
const size_t dst_count = (argc - optind - 3) / 2;
struct filepos *dsts = calloc(dst_count + 1, sizeof(struct filepos));
for (size_t i = 0; i < dst_count; i++) {
dsts[i].filename = argv[optind+3+(i*2)];
dsts[i].flags = ro ? O_RDONLY : O_RDWR;
if (!atou64(argv[optind+3+(i*2)+1], &dsts[i].offset))
error(2, errno, "invalid offset '%s'", argv[optind+3+(i*2)+1]);
}
dedupe_range(src_length, src, dsts);
free(dsts);
return EXIT_SUCCESS;
}
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