Commit d241f143 authored by Blue Swirl's avatar Blue Swirl

HACKING: add string management rules

Add string management rules, somewhat like libvirt HACKING.
Signed-off-by: default avatarBlue Swirl <blauwirbel@gmail.com>
parent 54b2cc50
......@@ -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.
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