| #include <assert.h> |
| #include <errno.h> |
| #include <limits.h> |
| #include <stdint.h> |
| #include <stdlib.h> |
| |
| #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; |
| } |