830464c3e4
All underlying glibc calls are free to return NULL if the size argument is 0. We most often call those functions with a fixed argument, or at least something which obviously cannot be zero, but it's too easy to forget. E.g. coverity complains about "rows = new0(JsonVariant*, n_rows-1);" in format-table.c There is an assert that n_rows > 0, so we could hit this corner case here. Let's simplify callers and make those functions "safe". CID #1397035. The compiler is mostly able to optimize this away: $ size build{,-opt}/src/shared/libsystemd-shared-239.so (before) text data bss dec hex filename 2643329 580940 3112 3227381 313ef5 build/src/shared/libsystemd-shared-239.so (-O0 -g) 2170013 578588 3089 2751690 29fcca build-opt/src/shared/libsystemd-shared-239.so (-03 -flto -g) (after) text data bss dec hex filename 2644017 580940 3112 3228069 3141a5 build/src/shared/libsystemd-shared-239.so 2170765 578588 3057 2752410 29ff9a build-opt/src/shared/libsystemd-shared-239.so
82 lines
1.6 KiB
C
82 lines
1.6 KiB
C
/* SPDX-License-Identifier: LGPL-2.1+ */
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#include <stdint.h>
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#include <string.h>
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#include "alloc-util.h"
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#include "macro.h"
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#include "util.h"
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void* memdup(const void *p, size_t l) {
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void *ret;
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assert(l == 0 || p);
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ret = malloc(l ?: 1);
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if (!ret)
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return NULL;
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memcpy(ret, p, l);
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return ret;
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}
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void* memdup_suffix0(const void *p, size_t l) {
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void *ret;
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assert(l == 0 || p);
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/* The same as memdup() but place a safety NUL byte after the allocated memory */
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ret = malloc(l + 1);
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if (!ret)
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return NULL;
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*((uint8_t*) mempcpy(ret, p, l)) = 0;
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return ret;
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}
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void* greedy_realloc(void **p, size_t *allocated, size_t need, size_t size) {
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size_t a, newalloc;
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void *q;
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assert(p);
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assert(allocated);
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if (*allocated >= need)
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return *p;
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newalloc = MAX(need * 2, 64u / size);
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a = newalloc * size;
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/* check for overflows */
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if (a < size * need)
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return NULL;
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q = realloc(*p, a);
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if (!q)
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return NULL;
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*p = q;
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*allocated = newalloc;
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return q;
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}
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void* greedy_realloc0(void **p, size_t *allocated, size_t need, size_t size) {
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size_t prev;
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uint8_t *q;
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assert(p);
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assert(allocated);
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prev = *allocated;
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q = greedy_realloc(p, allocated, need, size);
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if (!q)
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return NULL;
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if (*allocated > prev)
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memzero(q + prev * size, (*allocated - prev) * size);
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return q;
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}
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