#include "internal.h"
#pragma mark Utilities
-static int
-_sysctl_12809455(int mib[4], size_t mib_cnt, void *old, size_t *old_len,
- void *new, size_t new_len)
-{
- int error = -1;
- int ret = -1;
- size_t mylen = 0;
- size_t *mylenp = NULL;
-#if RDAR_12809455
- bool workaround_12809455 = false;
-#endif
-
- if (old_len) {
- mylen = *old_len;
- mylenp = &mylen;
- }
-
- // sysctl(3) doesn't behave anything like its documentation leads you to
- // believe. If the given buffer is too small to hold the requested data,
- // what's supposed to happen is:
- //
- // - as much data as possible is copied into the buffer
- // - the number of bytes copied is written to the len parameter
- // - errno is set to ENOMEM
- // - -1 is returned (to indicate that you should check errno)
- //
- // What actually happens:
- //
- // - no data is copied
- // - len is set to zero
- // - errno is undefined
- // - zero is returned
- //
- // So... swing and a miss.
- //
- // Since it returns success in this case our only indication that something
- // went wrong is if mylen is set to zero.
- //
- // So we do our best to sniff out the misbehavior and emulate sysctl(3)'s
- // API contract until it's fixed.
- //
- // <rdar://problem/12809455>
-#if RDAR_12809455
- if (old_len && *old_len > 0) {
- // We can only work around the bug if the passed-in length was non-zero.
- workaround_12809455 = true;
- }
-#endif
-
- ret = sysctl(mib, (u_int)mib_cnt, old, mylenp, new, new_len);
-#if RDAR_12809455
- if (workaround_12809455 && old && ret == 0 && mylen == 0) {
- ret = -1;
- errno = ENOMEM;
- }
-#endif // RDAR_12809455
-
- if (ret == 0) {
- error = 0;
- } else {
- error = errno;
- }
-
- if (old_len) {
- *old_len = mylen;
- }
-
- return error;
-}
-static char *
-_strblk(const char *str)
+/*
+ * Factored out from _get_parse_boot_arg_value for unit testing purposes
+ */
+static bool
+_parse_boot_arg_value(char *argsbuff, const char *which, char *where, size_t max)
{
- const char *cur = str;
+ bool found = false;
- while (*cur && !isblank(*cur)) {
- cur++;
+ char *token = NULL;
+ char *argsstr = argsbuff;
+ static const char seps[] = { ' ', '\t', };
+ while ((token = strsep(&argsstr, seps)) != NULL) {
+ bool is_boolean = false;
+
+ char *value = NULL;
+ char *equals = strchr(token, '=');
+ if (token[0] == '-') {
+ /*
+ * Arguments whose names begins with "-" are booleans, so don't get
+ * key=value splitting. Though I'd still discourage you from
+ * naming your option "-edge=case".
+ */
+ is_boolean = true;
+ } else if (equals) {
+ equals[0] = '\0';
+ value = &equals[1];
+ } else {
+ is_boolean = true;
+ }
+
+ if (strcmp(which, token) == 0) {
+ /*
+ * Found it! Copy out the value as required.
+ */
+ found = true;
+
+ if (!where) {
+ // Caller just wants to know whether the boot-arg exists.
+ } else if (is_boolean || value == NULL) {
+ strlcpy(where, "", max);
+ } else {
+ strlcpy(where, value, max);
+ }
+
+ break;
+ }
}
- return (char *)cur;
+ return found;
}
+/*
+ * This is (very) loosely based on the implementation of
+ * PE_parse_boot_argn() (or at least the parts where I was able to easily
+ * decipher the policy).
+ */
static bool
_get_boot_arg_value(const char *which, char *where, size_t max)
{
- // This is (very) loosely based on the implementation of
- // PE_parse_boot_argn() (or at least the parts where I was able to easily
- // decipher the policy).
bool found = false;
- errno_t error = -1;
- char *buff = NULL;
- size_t buff_len = 0;
- char *theone = NULL;
- char *equals = NULL;
-
- error = sysctlbyname_get_data_np("kern.bootargs", (void **)&buff,
- &buff_len);
- if (error) {
- goto __out;
- }
+ __os_free char *argsbuff = NULL;
+ size_t argsbuff_len = 0;
+ errno_t error = sysctlbyname_get_data_np("kern.bootargs",
+ (void **)&argsbuff, &argsbuff_len);
- theone = strstr(buff, which);
- if (!theone) {
- goto __out;
+ if (!error) {
+ found = _parse_boot_arg_value(argsbuff, which, where, max);
}
- found = true;
- if (!where) {
- // Caller just wants to know whether the boot-arg exists.
- goto __out;
- }
-
- equals = strchr(theone, '=');
- if (!equals || isblank(equals[1])) {
- strlcpy(where, "", max);
- } else {
- char *nextsep = NULL;
- char nextsep_old = 0;
-
- // Find the next separator and nerf it temporarily for the benefit of
- // the underlying strcpy(3).
- nextsep = _strblk(theone);
- nextsep_old = *nextsep;
- *nextsep = 0;
- strlcpy(where, &equals[1], max);
-
- *nextsep = nextsep_old;
- }
-
-__out:
- free(buff);
return found;
}
errno_t
sysctl_get_data_np(int mib[4], size_t mib_cnt, void **buff, size_t *buff_len)
{
- errno_t error = -1;
+ errno_t error = 0;
+ int ret = 0;
size_t needed = 0;
void *mybuff = NULL;
// We need to get the length of the parameter so we can allocate a buffer
// that's large enough.
- error = _sysctl_12809455(mib, mib_cnt, NULL, &needed, NULL, 0);
- if (error) {
+ ret = sysctl(mib, (unsigned int)mib_cnt, NULL, &needed, NULL, 0);
+ if (ret) {
+ error = errno;
goto __out;
}
goto __out;
}
- error = _sysctl_12809455(mib, mib_cnt, mybuff, &needed, NULL, 0);
- if (error) {
+ ret = sysctl(mib, (unsigned int)mib_cnt, mybuff, &needed, NULL, 0);
+ if (ret) {
// It's conceivable that some other process came along within this
// window and modified the variable to be even larger than we'd
// previously been told, but if that's the case, just give up.
+ error = errno;
goto __out;
}
projects / apple / libc.git / blobdiff