diff options
| -rw-r--r-- | lib/argv_split.c | 87 |
1 files changed, 40 insertions, 47 deletions
diff --git a/lib/argv_split.c b/lib/argv_split.c index 1e9a6cbc3689..e927ed0e18a8 100644 --- a/lib/argv_split.c +++ b/lib/argv_split.c @@ -8,23 +8,17 @@ #include <linux/slab.h> #include <linux/export.h> -static const char *skip_arg(const char *cp) -{ - while (*cp && !isspace(*cp)) - cp++; - - return cp; -} - static int count_argc(const char *str) { int count = 0; + bool was_space; - while (*str) { - str = skip_spaces(str); - if (*str) { + for (was_space = true; *str; str++) { + if (isspace(*str)) { + was_space = true; + } else if (was_space) { + was_space = false; count++; - str = skip_arg(str); } } @@ -39,10 +33,8 @@ static int count_argc(const char *str) */ void argv_free(char **argv) { - char **p; - for (p = argv; *p; p++) - kfree(*p); - + argv--; + kfree(argv[0]); kfree(argv); } EXPORT_SYMBOL(argv_free); @@ -59,43 +51,44 @@ EXPORT_SYMBOL(argv_free); * considered to be a single argument separator. The returned array * is always NULL-terminated. Returns NULL on memory allocation * failure. + * + * The source string at `str' may be undergoing concurrent alteration via + * userspace sysctl activity (at least). The argv_split() implementation + * attempts to handle this gracefully by taking a local copy to work on. */ char **argv_split(gfp_t gfp, const char *str, int *argcp) { - int argc = count_argc(str); - char **argv = kzalloc(sizeof(*argv) * (argc+1), gfp); - char **argvp; - - if (argv == NULL) - goto out; - - if (argcp) - *argcp = argc; - - argvp = argv; - - while (*str) { - str = skip_spaces(str); - - if (*str) { - const char *p = str; - char *t; - - str = skip_arg(str); + char *argv_str; + bool was_space; + char **argv, **argv_ret; + int argc; + + argv_str = kstrndup(str, KMALLOC_MAX_SIZE - 1, gfp); + if (!argv_str) + return NULL; + + argc = count_argc(argv_str); + argv = kmalloc(sizeof(*argv) * (argc + 2), gfp); + if (!argv) { + kfree(argv_str); + return NULL; + } - t = kstrndup(p, str-p, gfp); - if (t == NULL) - goto fail; - *argvp++ = t; + *argv = argv_str; + argv_ret = ++argv; + for (was_space = true; *argv_str; argv_str++) { + if (isspace(*argv_str)) { + was_space = true; + *argv_str = 0; + } else if (was_space) { + was_space = false; + *argv++ = argv_str; } } - *argvp = NULL; - - out: - return argv; + *argv = NULL; - fail: - argv_free(argv); - return NULL; + if (argcp) + *argcp = argc; + return argv_ret; } EXPORT_SYMBOL(argv_split); |