diff options
| -rw-r--r-- | gdb/ChangeLog | 6 | ||||
| -rw-r--r-- | gdb/c-lang.c | 25 | ||||
| -rw-r--r-- | gdb/testsuite/ChangeLog | 9 | ||||
| -rw-r--r-- | gdb/testsuite/gdb.python/py-value.c | 17 | ||||
| -rw-r--r-- | gdb/testsuite/gdb.python/py-value.exp | 6 |
5 files changed, 60 insertions, 3 deletions
diff --git a/gdb/ChangeLog b/gdb/ChangeLog index ed302dd..6c7fda5 100644 --- a/gdb/ChangeLog +++ b/gdb/ChangeLog @@ -1,5 +1,11 @@ 2013-12-10 Doug Evans <dje@google.com> + PR 16286 + * c-lang.c (c_get_string): Ignore the declared size of the object + if a specific length is requested. + +2013-12-10 Doug Evans <dje@google.com> + * interps.h (interp_exec_p): Delete. * interps.c (interp_exec_p): Delete. (interp_exec): Update. Assert interp->procs->exec_proc != NULL. diff --git a/gdb/c-lang.c b/gdb/c-lang.c index eecc76d..2c075f4 100644 --- a/gdb/c-lang.c +++ b/gdb/c-lang.c @@ -227,9 +227,13 @@ c_printstr (struct ui_file *stream, struct type *type, until a null character of the appropriate width is found, otherwise the string is read to the length of characters specified. The size of a character is determined by the length of the target type of - the pointer or array. If VALUE is an array with a known length, - the function will not read past the end of the array. On - completion, *LENGTH will be set to the size of the string read in + the pointer or array. + + If VALUE is an array with a known length, and *LENGTH is -1, + the function will not read past the end of the array. However, any + declared size of the array is ignored if *LENGTH > 0. + + On completion, *LENGTH will be set to the size of the string read in characters. (If a length of -1 is specified, the length returned will not include the null character). CHARSET is always set to the target charset. */ @@ -309,6 +313,21 @@ c_get_string (struct value *value, gdb_byte **buffer, { CORE_ADDR addr = value_as_address (value); + /* Prior to the fix for PR 16196 read_string would ignore fetchlimit + if length > 0. The old "broken" behaviour is the behaviour we want: + The caller may want to fetch 100 bytes from a variable length array + implemented using the common idiom of having an array of length 1 at + the end of a struct. In this case we want to ignore the declared + size of the array. However, it's counterintuitive to implement that + behaviour in read_string: what does fetchlimit otherwise mean if + length > 0. Therefore we implement the behaviour we want here: + If *length > 0, don't specify a fetchlimit. This preserves the + previous behaviour. We could move this check above where we know + whether the array is declared with a fixed size, but we only want + to apply this behaviour when calling read_string. PR 16286. */ + if (*length > 0) + fetchlimit = UINT_MAX; + err = read_string (addr, *length, width, fetchlimit, byte_order, buffer, length); if (err) diff --git a/gdb/testsuite/ChangeLog b/gdb/testsuite/ChangeLog index ec01bff..c850604 100644 --- a/gdb/testsuite/ChangeLog +++ b/gdb/testsuite/ChangeLog @@ -1,3 +1,12 @@ +2013-12-10 Doug Evans <dje@google.com> + + * gdb.python/py-value.c: #include stdlib.h, string.h. + (str): New struct. + (main): New local xstr. + * gdb.python/py-value.exp (test_value_in_inferior): Add test to + fetch a value as a string with a length beyond the declared length + of the array. + 2013-12-10 Andrew Burgess <aburgess@broadcom.com> * lib/gdb.exp (gdb_compile_shlib): Add call to get_compiler_info, diff --git a/gdb/testsuite/gdb.python/py-value.c b/gdb/testsuite/gdb.python/py-value.c index 0c94e64..4f8c27b 100644 --- a/gdb/testsuite/gdb.python/py-value.c +++ b/gdb/testsuite/gdb.python/py-value.c @@ -16,6 +16,8 @@ along with this program. If not, see <http://www.gnu.org/licenses/>. */ #include <stdio.h> +#include <stdlib.h> +#include <string.h> struct s { @@ -39,6 +41,13 @@ typedef struct s *PTR; enum e evalue = TWO; +struct str +{ + int length; + /* Variable length. */ + char text[1]; +}; + #ifdef __cplusplus struct Base { @@ -86,6 +95,8 @@ main (int argc, char *argv[]) int i = 2; int *ptr_i = &i; const char *sn = 0; + struct str *xstr; + s.a = 3; s.b = 5; u.a = 7; @@ -96,6 +107,12 @@ main (int argc, char *argv[]) ptr_ref(ptr_i); #endif +#define STR_LENGTH 100 + xstr = (struct str *) malloc (sizeof (*xstr) + STR_LENGTH); + xstr->length = STR_LENGTH; + memset (xstr->text, 'x', STR_LENGTH); +#undef STR_LENGTH + save_argv = argv; /* break to inspect struct and union */ return 0; } diff --git a/gdb/testsuite/gdb.python/py-value.exp b/gdb/testsuite/gdb.python/py-value.exp index 43de063..a052104 100644 --- a/gdb/testsuite/gdb.python/py-value.exp +++ b/gdb/testsuite/gdb.python/py-value.exp @@ -291,6 +291,12 @@ proc test_value_in_inferior {} { # For the purposes of this test, use repr() gdb_py_test_silent_cmd "python nullst = nullst.string (length = 9)" "get string beyond null" 1 gdb_test "python print (repr(nullst))" "u?'divide\\\\x00et'" + + # Test fetching a string longer than its declared (in C) size. + # PR 16286 + gdb_py_test_silent_cmd "python xstr = gdb.parse_and_eval('xstr')" "get xstr" 1 + gdb_test "python print xstr\['text'\].string (length = xstr\['length'\])" "x{100}" \ + "read string beyond declared size" } proc test_lazy_strings {} { |