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#include <assert.h>
#include <blake3.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "utils.h"
#include "checksums.h"
/* reads f and returns the checksum */
static char *
file_checksum(FILE *f) {
/* This function is essentially copied from b3sum:
* https://git.sr.ht/~mcf/b3sum/tree/cb4111ccc8061039b014fbb657c72f78984f1069/item/b3sum.c#L19
* which is used under CC0. */
size_t outlen = 33, len;
unsigned char *out = malloc(outlen);
if (out == NULL)
die_perror("malloc");
size_t buflen = 0x4000;
char *buf = malloc(buflen);
if (buf == NULL)
die_perror("malloc");
blake3_hasher ctx;
blake3_hasher_init(&ctx);
do {
len = fread(buf, 1, buflen, f);
if (len > 0)
blake3_hasher_update(&ctx, buf, len);
} while (len == buflen);
if (ferror(f))
die_perror("fread");
blake3_hasher_finalize(&ctx, out, outlen);
free(buf);
size_t hexlen = 2 * outlen;
char *hex = malloc(hexlen + 1);
if (hex == NULL)
die_perror("malloc");
for (size_t i = 0; i < outlen; i++)
sprintf(hex + 2*i, "%02x", out[i]);
hex[hexlen] = '\0';
free(out);
return hex;
}
/* returns the checksum of the file specified by s, if needed and if the cache
* is present (must download first) */
char *
source_generate_checksum(struct source *s) {
assert(s);
if (s->type != SRC_HTTP && s->type != SRC_FILE)
return NULL; /* checksum not needed */
FILE *f = fopen(s->cachefile, "rb");
if (f == NULL)
die_perror(s->cachefile);
char *c = file_checksum(f);
fclose(f);
return c;
}
/* dies if there is a checksum mismatch. */
void
verify_checksums(struct pkg *p) {
assert(p);
FILE *f = pkg_open_file(p->pkg_path, "checksums", "r");
if (f == NULL) {
if (p->n_need_checksums == 0)
return;
else
die2(p->pkg, "checksums needed but no checksum file");
}
assert(p->s);
char *buf = NULL;
size_t bufn = 0;
ssize_t n;
for (size_t i = 0; i < p->n; i++) {
if (p->s[i]->type != SRC_HTTP && p->s[i]->type != SRC_FILE)
continue;
if ((n = getline(&buf, &bufn, f)) == -1) {
free(buf);
fclose(f);
perror(NULL);
die2(p->s[i]->remote, "checksums missing");
}
if (buf[n - 1] == '\n')
buf[--n] = '\0';
char *sum = source_generate_checksum(p->s[i]);
if (strcmp(buf, sum) != 0) {
free(sum);
free(buf);
fclose(f);
die2(p->s[i]->cachefile, "checksum mismatch");
}
free(sum);
}
free(buf);
fclose(f);
}
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