diff options
Diffstat (limited to 'HACKING')
| -rw-r--r-- | HACKING | 24 |
1 files changed, 24 insertions, 0 deletions
@@ -86,3 +86,27 @@ that qemu_malloc() call with zero size is not allowed. Memory allocated by qemu_vmalloc or qemu_memalign must be freed with qemu_vfree, since breaking this will cause problems on Win32 and user emulators. + +4. String manipulation + +Do not use the strncpy function. According to the man page, it does +*not* guarantee a NULL-terminated buffer, which makes it extremely dangerous +to use. Instead, use functionally equivalent function: +void pstrcpy(char *buf, int buf_size, const char *str) + +Don't use strcat because it can't check for buffer overflows, but: +char *pstrcat(char *buf, int buf_size, const char *s) + +The same limitation exists with sprintf and vsprintf, so use snprintf and +vsnprintf. + +QEMU provides other useful string functions: +int strstart(const char *str, const char *val, const char **ptr) +int stristart(const char *str, const char *val, const char **ptr) +int qemu_strnlen(const char *s, int max_len) + +There are also replacement character processing macros for isxyz and toxyz, +so instead of e.g. isalnum you should use qemu_isalnum. + +Because of the memory management rules, you must use qemu_strdup/qemu_strndup +instead of plain strdup/strndup. |