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 #include #include #include #include #include #include "extents.h" #define TRUE 1 #define FALSE 0 /* Minimum/maximum values for arbitrary integer types. */ #define UNSIGNED_INT_MAX(t) (~((t)0)) #define SIGNED_INT_MAX(t) ((t)((uintmax_t)UNSIGNED_INT_MAX(t) >> 1)) #define MAX(a,b) ((a) > (b) ? (a) : (b)) #define INT_TYPE_MAX(t) MAX(UNSIGNED_INT_MAX(t), SIGNED_INT_MAX(t)) /* The maximum accepted value for a given integer type when parsed as a signed * long long integer. This is defined to be the smaller of the maximum value * that can be represented by this type and LLONG_MAX. This bound allows us to * properly check that parsed values do not exceed the capacity of their * intended store, regardless of how its size relates to that of a signed long * long integer. Note: this may mean that we are losing the most significant * bit of an unsigned 64-bit field (e.g. size_t on some platforms), however * still permitting values up to 2^62, which is more than enough for all * practical purposes. */ #define LLONG_MAX_BOUND(s) \ ((uintmax_t)(s) < (uintmax_t)LLONG_MAX ? (long long)(s) : LLONG_MAX) #define MAX_ALLOWED(t) LLONG_MAX_BOUND(INT_TYPE_MAX(t)) /* Get the type of a struct field. */ #define FIELD_TYPE(t, f) typeof(((t *)0)->f) /* Reads a long long integer from |s| into |*val_p|. Returns a pointer to the * character immediately following the specified |delim|, unless (a) parsing * failed (overflow or no valid digits); (b) the read value is less than * |min_val| or greater than |max_val|; (c) the delimiter character is not * |delim|, or the string ends although |may_end| is false. In any of these * cases, returns NULL. */ const char * read_llong(const char *s, long long *val_p, long long min_val, long long max_val, char delim, int may_end) { assert(val_p); const char *next_s; errno = 0; long long val = strtoll(s, (char **)&next_s, 10); if (((val == LLONG_MAX || val == LLONG_MIN) && errno == ERANGE) || next_s == s || val < min_val || val > max_val || (*next_s ? *next_s != delim : !may_end)) return NULL; /* bad value or delimiter */ *val_p = val; if (*next_s) next_s++; /* skip delimeter */ return next_s; } /* Reads a comma-separated list of "offset:length" extents from |ex_str|. If * |ex_arr| is NULL, then |ex_count| is ignored and it attempts to parse valid * extents until the end of the string is reached. Otherwise, stores up to * |ex_count| extents into |ex_arr|, which must be of at least this size. * Returns the number of correctly parsed extents, or -1 if a malformed extent * was found. */ static ssize_t extents_read(const char *ex_str, ex_t *ex_arr, size_t ex_count) { size_t i; size_t last_i = ex_count - 1; if (!ex_arr) { ex_count = SIZE_MAX; last_i = 0; } for (i = 0; *ex_str && i < ex_count; i++) { long long raw_off = 0, raw_len = 0; if (!((ex_str = read_llong(ex_str, &raw_off, -1, MAX_ALLOWED(FIELD_TYPE(ex_t, off)), ':', FALSE)) && (ex_str = read_llong(ex_str, &raw_len, 1, MAX_ALLOWED(FIELD_TYPE(ex_t, len)), ',', i >= last_i)))) return -1; /* parsing error */ if (ex_arr) { ex_arr[i].off = raw_off; ex_arr[i].len = raw_len; } } return i; } ex_t * extents_parse(const char *ex_str, ex_t *ex_arr, size_t *ex_count_p) { /* Sanity checks: a string must be provided; if an array is provided, an * array count must be given as well. */ if (!ex_str || (ex_arr && !ex_count_p)) return NULL; /* Parse string and count extents. */ ssize_t ret = extents_read(ex_str, NULL, 0); if (ret < 0) return NULL; /* parsing error */ size_t ex_count = (size_t)ret; /* Input is good, commit to extent count. */ if (ex_count_p) { size_t alloc_ex_count = *ex_count_p; *ex_count_p = ex_count; if (ex_arr && alloc_ex_count < ex_count) return NULL; /* insufficient allocated space */ } if (ex_count == 0) return NULL; /* no extents, nothing to do */ /* Allocate extent array, if needed. */ if (!(ex_arr || (ex_arr = (ex_t *)malloc(sizeof(ex_t) * ex_count)))) return NULL; /* allocation failed */ /* Populate the extent array. */ extents_read(ex_str, ex_arr, ex_count); return ex_arr; }