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settings: Clean up NVRAM code

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Code style fixes, tighten error checking, replace a static buffer
with a stack allocated one.

Change-Id: I48392fa187057cc4a07847d45147f0db9f43f509
This commit is contained in:
Aidan MacDonald 2022-11-30 12:48:09 +00:00
parent 961e73b3a1
commit a89f279fd4
1 changed files with 69 additions and 62 deletions
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131
apps/settings.c
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@ -123,97 +123,103 @@ long lasttime = 0;
/** NVRAM stuff, if the target doesnt have NVRAM it is saved in ROCKBOX_DIR /nvram.bin **/
/* NVRAM is set out as
[0] 'R'
[1] 'b'
[2] version
[3] stored variable count
[4-7] crc32 checksum
[8-NVRAM_BLOCK_SIZE] data
*/
static char nvram_buffer[NVRAM_BLOCK_SIZE];
*
* [0] 'R'
* [1] 'b'
* [2] version
* [3] stored variable count
* [4-7] crc32 checksum in host endian order
* [8+] data
*/
static bool read_nvram_data(char* buf, int max_len)
static unsigned int nvram_crc(char *buf, int max_len)
{
return crc_32(&buf[NVRAM_DATA_START], max_len - NVRAM_DATA_START - 1, 0xffffffff);
}
static void read_nvram_data(void)
{
rename_temp_file(NVRAM_FILE_TEMP, NVRAM_FILE, NVRAM_FILE".old");
unsigned crc32 = 0xffffffff;
int var_count = 0, i = 0, buf_pos = 0;
int fd = open(NVRAM_FILE, O_RDONLY);
int bytes;
if (fd < 0)
return false;
memset(buf,0,max_len);
bytes = read(fd,buf,max_len);
return;
char buf[NVRAM_BLOCK_SIZE];
memset(buf, 0, sizeof(buf));
ssize_t bytes = read(fd, buf, sizeof(buf));
close(fd);
if (bytes < 8) /* min is 8 bytes,magic, ver, vars, crc32 */
return false;
return;
/* check magic, version */
if ((buf[0] != 'R') || (buf[1] != 'b')
|| (buf[2] != NVRAM_CONFIG_VERSION))
return false;
if (buf[0] != 'R' || buf[1] != 'b' || buf[2] != NVRAM_CONFIG_VERSION)
return;
/* check crc32 */
crc32 = crc_32(&buf[NVRAM_DATA_START],
max_len-NVRAM_DATA_START-1,0xffffffff);
if (memcmp(&crc32,&buf[4],4))
return false;
unsigned int crc32 = nvram_crc(buf, sizeof(buf));
if (crc32 != load_h32(&buf[4]))
return;
/* all good, so read in the settings */
var_count = buf[3];
buf_pos = NVRAM_DATA_START;
for(i=0; i<nb_settings; i++)
int var_count = buf[3];
size_t buf_pos = NVRAM_DATA_START;
for(int i = 0; i < nb_settings; i++)
{
int nvram_bytes = (settings[i].flags&F_NVRAM_BYTES_MASK)
>>F_NVRAM_MASK_SHIFT;
const struct settings_list *setting = &settings[i];
int nvram_bytes = (setting->flags & F_NVRAM_BYTES_MASK) >> F_NVRAM_MASK_SHIFT;
if (nvram_bytes)
{
if ((var_count>0) && (buf_pos<max_len))
if (var_count > 0 && buf_pos < (size_t)bytes)
{
memcpy(settings[i].setting,&buf[buf_pos],nvram_bytes);
memcpy(setting->setting, &buf[buf_pos], nvram_bytes);
buf_pos += nvram_bytes;
var_count--;
}
else /* should only happen when new items are added to the end */
{
memcpy(settings[i].setting, &settings[i].default_val, nvram_bytes);
memcpy(setting->setting, &setting->default_val, nvram_bytes);
}
}
}
return true;
}
static bool write_nvram_data(char* buf, int max_len)
static void write_nvram_data(void)
{
unsigned crc32 = 0xffffffff;
int i = 0, buf_pos = 0;
char var_count = 0;
int fd;
memset(buf,0,max_len);
char buf[NVRAM_BLOCK_SIZE];
memset(buf, 0, sizeof(buf));
/* magic, version */
buf[0] = 'R'; buf[1] = 'b';
buf[0] = 'R';
buf[1] = 'b';
buf[2] = NVRAM_CONFIG_VERSION;
buf_pos = NVRAM_DATA_START;
for(i=0; (i<nb_settings) && (buf_pos<max_len); i++)
size_t buf_pos = NVRAM_DATA_START;
int var_count = 0;
for(int i = 0; i < nb_settings && buf_pos < sizeof(buf); i++)
{
int nvram_bytes = (settings[i].flags&F_NVRAM_BYTES_MASK)
>>F_NVRAM_MASK_SHIFT;
const struct settings_list *setting = &settings[i];
int nvram_bytes = (setting->flags & F_NVRAM_BYTES_MASK) >> F_NVRAM_MASK_SHIFT;
if (nvram_bytes)
{
memcpy(&buf[buf_pos],settings[i].setting,nvram_bytes);
memcpy(&buf[buf_pos], setting->setting, nvram_bytes);
buf_pos += nvram_bytes;
var_count++;
}
}
/* count and crc32 */
buf[3] = var_count;
crc32 = crc_32(&buf[NVRAM_DATA_START],
max_len-NVRAM_DATA_START-1,0xffffffff);
memcpy(&buf[4],&crc32,4);
fd = open(NVRAM_FILE_TEMP,O_CREAT|O_TRUNC|O_WRONLY, 0666);
if (fd >= 0)
{
int len = write(fd,buf,max_len);
close(fd);
if (len < 8)
return false;
}
return true;
store_h32(&buf[4], nvram_crc(buf, sizeof(buf)));
int fd = open(NVRAM_FILE_TEMP,O_CREAT|O_TRUNC|O_WRONLY, 0666);
if (fd < 0)
return;
write(fd, buf, sizeof(buf));
close(fd);
}
/** Reading from a config file **/
@ -222,9 +228,9 @@ static bool write_nvram_data(char* buf, int max_len)
*/
void settings_load(int which)
{
if (which&SETTINGS_RTC)
read_nvram_data(nvram_buffer,NVRAM_BLOCK_SIZE);
if (which&SETTINGS_HD)
if (which & SETTINGS_RTC)
read_nvram_data();
if (which & SETTINGS_HD)
{
rename_temp_file(CONFIGFILE_TEMP, CONFIGFILE, CONFIGFILE".old");
settings_load_config(CONFIGFILE, false);
@ -604,16 +610,17 @@ static bool settings_write_config(const char* filename, int options)
static void flush_global_status_callback(void)
{
write_nvram_data(nvram_buffer,NVRAM_BLOCK_SIZE);
write_nvram_data();
}
static void flush_config_block_callback(void)
{
write_nvram_data(nvram_buffer,NVRAM_BLOCK_SIZE);
write_nvram_data();
settings_write_config(CONFIGFILE_TEMP, SETTINGS_SAVE_CHANGED);
}
void reset_runtime(void) {
void reset_runtime(void)
{
lasttime = current_tick;
global_status.runtime = 0;
}