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uuidgen: generate UUIDs in bounded batches to respect kernel limit #1965

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uuidgen: generate UUIDs in bounded batches to respect kernel limit #1965

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90 changes: 51 additions & 39 deletions bin/uuidgen/uuidgen.c
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Original file line number Diff line number Diff line change
Expand Up @@ -34,6 +34,13 @@
#include <stdlib.h>
#include <unistd.h>
#include <uuid.h>
/*
* sys_uuidgen(2) limits the number of UUIDs generated per call
* to 2048 (see sys/kern/kern_uuid.c). As this limit is not
* exposed via a sysctl or public header, mirror it here to
* avoid EINVAL and unbounded allocations.
*/
#define UUIDGEN_BATCH_MAX 2048

static void
usage(void)
Expand Down Expand Up @@ -156,46 +163,51 @@ main(int argc, char *argv[])
if (count == -1)
count = 1;

store = (uuid_t *)malloc(sizeof(uuid_t) * count);
if (store == NULL)
err(1, "malloc()");

if (!iterate) {
/* Get them all in a single batch */
if (version == 1) {
if (uuidgen(store, count) != 0)
err(1, "uuidgen()");
} else if (version == 4) {
if (uuidgen_v4(store, count) != 0)
err(1, "uuidgen_v4()");
} else {
err(1, "unsupported version");
}
} else {
uuid = store;
for (i = 0; i < count; i++) {
if (version == 1) {
if (uuidgen(uuid++, 1) != 0)
err(1, "uuidgen()");
} else if (version == 4) {
if (uuidgen_v4(uuid++, 1) != 0)
err(1, "uuidgen_v4()");
} else {
err(1, "unsupported version");
}
}
}

uuid = store;
while (count--) {
tostring(uuid++, &p, &status);
if (status != uuid_s_ok)
err(1, "cannot stringify a UUID");
fprintf(fp, "%s\n", p);
free(p);
}
store = calloc(UUIDGEN_BATCH_MAX, sizeof(uuid_t));
if (store == NULL)
err(1, "calloc()");

while (count > 0) {
int batch = (count > UUIDGEN_BATCH_MAX) ? UUIDGEN_BATCH_MAX : count;

if (!iterate) {
if (version == 1) {
if (uuidgen(store, batch) != 0)
err(1, "uuidgen()");
} else if (version == 4) {
if (uuidgen_v4(store, batch) != 0)
err(1, "uuidgen_v4()");
} else {
err(1, "unsupported version");
}
} else {
uuid = store;
for (i = 0; i < batch; i++) {
if (version == 1) {
if (uuidgen(uuid++, 1) != 0)
err(1, "uuidgen()");
} else if (version == 4) {
if (uuidgen_v4(uuid++, 1) != 0)
err(1, "uuidgen_v4()");
} else {
err(1, "unsupported version");
}
}
}

uuid = store;
for (i = 0; i < batch; i++) {
tostring(uuid++, &p, &status);
if (status != uuid_s_ok)
err(1, "cannot stringify a UUID");
fprintf(fp, "%s\n", p);
free(p);
}

count -= batch;
}
free(store);

free(store);
if (fp != stdout)
fclose(fp);
return (0);
Expand Down
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