diff options
Diffstat (limited to 'git-compat-util.h')
| -rw-r--r-- | git-compat-util.h | 108 |
1 files changed, 98 insertions, 10 deletions
diff --git a/git-compat-util.h b/git-compat-util.h index 2acef3f113..c07e0c1778 100644 --- a/git-compat-util.h +++ b/git-compat-util.h @@ -96,6 +96,14 @@ #define unsigned_add_overflows(a, b) \ ((b) > maximum_unsigned_value_of_type(a) - (a)) +/* + * Returns true if the multiplication of "a" and "b" will + * overflow. The types of "a" and "b" must match and must be unsigned. + * Note that this macro evaluates "a" twice! + */ +#define unsigned_mult_overflows(a, b) \ + ((a) && (b) > maximum_unsigned_value_of_type(a) / (a)) + #ifdef __GNUC__ #define TYPEOF(x) (__typeof__(x)) #else @@ -669,7 +677,6 @@ extern int git_vsnprintf(char *str, size_t maxsize, #ifdef __GLIBC_PREREQ #if __GLIBC_PREREQ(2, 1) #define HAVE_STRCHRNUL -#define HAVE_MEMPCPY #endif #endif @@ -683,14 +690,6 @@ static inline char *gitstrchrnul(const char *s, int c) } #endif -#ifndef HAVE_MEMPCPY -#define mempcpy gitmempcpy -static inline void *gitmempcpy(void *dest, const void *src, size_t n) -{ - return (char *)memcpy(dest, src, n) + n; -} -#endif - #ifdef NO_INET_PTON int inet_pton(int af, const char *src, void *dst); #endif @@ -709,6 +708,32 @@ extern void release_pack_memory(size_t); typedef void (*try_to_free_t)(size_t); extern try_to_free_t set_try_to_free_routine(try_to_free_t); +static inline size_t st_add(size_t a, size_t b) +{ + if (unsigned_add_overflows(a, b)) + die("size_t overflow: %"PRIuMAX" + %"PRIuMAX, + (uintmax_t)a, (uintmax_t)b); + return a + b; +} +#define st_add3(a,b,c) st_add((a),st_add((b),(c))) +#define st_add4(a,b,c,d) st_add((a),st_add3((b),(c),(d))) + +static inline size_t st_mult(size_t a, size_t b) +{ + if (unsigned_mult_overflows(a, b)) + die("size_t overflow: %"PRIuMAX" * %"PRIuMAX, + (uintmax_t)a, (uintmax_t)b); + return a * b; +} + +static inline size_t st_sub(size_t a, size_t b) +{ + if (a < b) + die("size_t underflow: %"PRIuMAX" - %"PRIuMAX, + (uintmax_t)a, (uintmax_t)b); + return a - b; +} + #ifdef HAVE_ALLOCA_H # include <alloca.h> # define xalloca(size) (alloca(size)) @@ -741,7 +766,70 @@ extern int odb_pack_keep(char *name, size_t namesz, const unsigned char *sha1); extern char *xgetcwd(void); extern FILE *fopen_for_writing(const char *path); -#define REALLOC_ARRAY(x, alloc) (x) = xrealloc((x), (alloc) * sizeof(*(x))) +#define ALLOC_ARRAY(x, alloc) (x) = xmalloc(st_mult(sizeof(*(x)), (alloc))) +#define REALLOC_ARRAY(x, alloc) (x) = xrealloc((x), st_mult(sizeof(*(x)), (alloc))) + +/* + * These functions help you allocate structs with flex arrays, and copy + * the data directly into the array. For example, if you had: + * + * struct foo { + * int bar; + * char name[FLEX_ARRAY]; + * }; + * + * you can do: + * + * struct foo *f; + * FLEX_ALLOC_MEM(f, name, src, len); + * + * to allocate a "foo" with the contents of "src" in the "name" field. + * The resulting struct is automatically zero'd, and the flex-array field + * is NUL-terminated (whether the incoming src buffer was or not). + * + * The FLEXPTR_* variants operate on structs that don't use flex-arrays, + * but do want to store a pointer to some extra data in the same allocated + * block. For example, if you have: + * + * struct foo { + * char *name; + * int bar; + * }; + * + * you can do: + * + * struct foo *f; + * FLEX_ALLOC_STR(f, name, src); + * + * and "name" will point to a block of memory after the struct, which will be + * freed along with the struct (but the pointer can be repointed anywhere). + * + * The *_STR variants accept a string parameter rather than a ptr/len + * combination. + * + * Note that these macros will evaluate the first parameter multiple + * times, and it must be assignable as an lvalue. + */ +#define FLEX_ALLOC_MEM(x, flexname, buf, len) do { \ + (x) = NULL; /* silence -Wuninitialized for offset calculation */ \ + (x) = xalloc_flex(sizeof(*(x)), (char *)(&((x)->flexname)) - (char *)(x), (buf), (len)); \ +} while (0) +#define FLEXPTR_ALLOC_MEM(x, ptrname, buf, len) do { \ + (x) = xalloc_flex(sizeof(*(x)), sizeof(*(x)), (buf), (len)); \ + (x)->ptrname = (void *)((x)+1); \ +} while(0) +#define FLEX_ALLOC_STR(x, flexname, str) \ + FLEX_ALLOC_MEM((x), flexname, (str), strlen(str)) +#define FLEXPTR_ALLOC_STR(x, ptrname, str) \ + FLEXPTR_ALLOC_MEM((x), ptrname, (str), strlen(str)) + +static inline void *xalloc_flex(size_t base_len, size_t offset, + const void *src, size_t src_len) +{ + unsigned char *ret = xcalloc(1, st_add3(base_len, src_len, 1)); + memcpy(ret + offset, src, src_len); + return ret; +} static inline char *xstrdup_or_null(const char *str) { |