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nwztool/scsitool: rewrite device detection on linux to make it simpler

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Change-Id: I8f393a53ea64c82f05e437923bcba05aa8a7a75c
This commit is contained in:
Amaury Pouly 2020-01-12 23:12:18 +01:00
parent 9e94a5eadc
commit ee15e45224
1 changed files with 27 additions and 103 deletions
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130
utils/scsi/rbscsi.c
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@ -157,52 +157,10 @@ void rb_scsi_close(rb_scsi_device_t dev)
free(dev);
}
static int is_hctl(const char *name)
{
char *end;
strtoul(name, &end, 0); /* h */
if(*end != ':')
return 0;
strtoul(end + 1, &end, 0); /* c */
if(*end != ':')
return 0;
strtoul(end + 1, &end, 0); /* t */
if(*end != ':')
return 0;
strtoul(end + 1, &end, 0); /* l */
return *end == 0;
}
static int _resolve_link_dev_path(char *path, size_t pathsz)
{
/* make sure it is a directory */
struct stat st;
if(stat(path, &st) < 0)
return 0;
if(!S_ISDIR(st.st_mode))
return 0;
if(chdir(path) < 0)
return 0;
if(getcwd(path, pathsz) == NULL)
return 0;
return 1;
}
static int resolve_link_dev_path(char *path, size_t pathsz)
{
/* change directory, ask the current path and resolve current directory */
char curdir[PATH_MAX];
if(getcwd(curdir, sizeof(curdir)) == NULL)
return 0;
int ret = _resolve_link_dev_path(path, pathsz);
chdir(curdir);
return ret;
}
/* find the first entry of a directory (which is expended to contain only one) and turn
* it into a /dev/ path */
static int scan_resolve_first_dev_path(char *path, size_t pathsz)
{
size_t pathlen = strlen(path);
char *pathend = path + pathlen;
DIR *dir = opendir(path);
if(dir == NULL)
return 0;
@ -212,13 +170,8 @@ static int scan_resolve_first_dev_path(char *path, size_t pathsz)
{
if(!strcmp(d->d_name, ".") || !strcmp(d->d_name, ".."))
continue;
/* we found the entry, if it is a symlink, resolve it, otherwise it must be a directory */
if(d->d_type == DT_LNK)
{
snprintf(pathend, pathsz - pathlen, "/%s", d->d_name);
ret = resolve_link_dev_path(path, pathsz);
}
else if(d->d_type == DT_DIR)
/* we expect a directory, but it could be a symlink, only the name matters */
if(d->d_type == DT_LNK || d->d_type == DT_DIR)
{
snprintf(path, pathsz, "/dev/%s", d->d_name);
ret = 1;
@ -229,33 +182,6 @@ static int scan_resolve_first_dev_path(char *path, size_t pathsz)
return ret;
}
static int scan_resolve_dev_path(char *path, size_t pathsz, const char *match)
{
size_t pathlen = strlen(path);
char *pathend = path + pathlen;
DIR *dir = opendir(path);
if(dir == NULL)
return 0;
struct dirent *d;
int ret = 0;
while((d = readdir(dir)))
{
if(strcmp(d->d_name, match))
continue;
/* we found the entry, there are two case:
* - directory: we need to scan it and find the first entry
* - symlink: we need to see where it goes and extract the basename */
snprintf(pathend, pathsz - pathlen, "/%s", d->d_name);
if(d->d_type == DT_DIR)
ret = scan_resolve_first_dev_path(path, pathsz);
else if(d->d_type == DT_LNK)
ret = resolve_link_dev_path(path, pathsz);
break;
}
closedir(dir);
return ret;
}
static char *read_file_or_null(const char *path)
{
FILE *f = fopen(path, "r");
@ -277,9 +203,9 @@ static char *read_file_or_null(const char *path)
struct rb_scsi_devent_t *rb_scsi_list(void)
{
/* list devices in /sys/bus/scsi/devices
* we only keep entries of the form h:c:t:l */
#define SYS_SCSI_DEV_PATH "/sys/bus/scsi/devices"
/* list devices in /sys/class/scsi_generic
* we only keep entries of the form sgX */
#define SYS_SCSI_DEV_PATH "/sys/class/scsi_generic"
DIR *dir = opendir(SYS_SCSI_DEV_PATH);
if(dir == NULL)
return NULL;
@ -292,31 +218,29 @@ struct rb_scsi_devent_t *rb_scsi_list(void)
{
if(!strcmp(d->d_name, ".") || !strcmp(d->d_name, ".."))
continue;
/* make sure the name is of the form h:c:t:l, we do not want targets or hosts */
if(!is_hctl(d->d_name))
/* make sure the name is of the form sgX, and extract X */
int sg_idx;
if(sscanf(d->d_name, "sg%d", &sg_idx) != 1)
continue;
/* we now need to scan the directory to find the block and scsi generic device path:
* block: there should be a 'block' entry
* scsi: there should be a 'scsi_generic' entry
* Both entries can either be a symlink to the devide, or a directory with a single entry */
char scsi_path[PATH_MAX];
snprintf(scsi_path, sizeof(scsi_path), SYS_SCSI_DEV_PATH "/%s", d->d_name);
if(!scan_resolve_dev_path(scsi_path, sizeof(scsi_path), "scsi_generic"))
continue;
char block_path[PATH_MAX];
snprintf(block_path, sizeof(block_path), SYS_SCSI_DEV_PATH "/%s", d->d_name);
if(!scan_resolve_dev_path(block_path, sizeof(block_path), "block"))
block_path[0] = 0;
dev = realloc(dev, (2 + nr_dev) * sizeof(struct rb_scsi_devent_t));
dev[nr_dev].scsi_path = strdup(scsi_path);
dev[nr_dev].block_path = block_path[0] == 0 ? NULL : strdup(block_path);
char path[PATH_MAX];
snprintf(path, sizeof(path), "/dev/sg%d", sg_idx);
dev[nr_dev].scsi_path = strdup(path);
/* /sys/class/scsi_generic/sgX is a folder containing a subfolder 'device' that contains
* - a 'block' folder with a single entry: the block device
* - the vendor/model/rev files */
snprintf(path, sizeof(path), SYS_SCSI_DEV_PATH "/sg%d/device/block", sg_idx);
if(!scan_resolve_first_dev_path(path, sizeof(path)))
path[0] = 0;
dev[nr_dev].block_path = path[0] == 0 ? NULL : strdup(path);
/* fill vendor/model/rev */
snprintf(scsi_path, sizeof(scsi_path), SYS_SCSI_DEV_PATH "/%s/vendor", d->d_name);
dev[nr_dev].vendor = read_file_or_null(scsi_path);
snprintf(scsi_path, sizeof(scsi_path), SYS_SCSI_DEV_PATH "/%s/model", d->d_name);
dev[nr_dev].model = read_file_or_null(scsi_path);
snprintf(scsi_path, sizeof(scsi_path), SYS_SCSI_DEV_PATH "/%s/rev", d->d_name);
dev[nr_dev].rev = read_file_or_null(scsi_path);
snprintf(path, sizeof(path), SYS_SCSI_DEV_PATH "/sg%d/device/vendor", sg_idx);
dev[nr_dev].vendor = read_file_or_null(path);
snprintf(path, sizeof(path), SYS_SCSI_DEV_PATH "/sg%d/device/model", sg_idx);
dev[nr_dev].model = read_file_or_null(path);
snprintf(path, sizeof(path), SYS_SCSI_DEV_PATH "/sg%d/device/rev", sg_idx);
dev[nr_dev].rev = read_file_or_null(path);
/* sentinel */
dev[++nr_dev].scsi_path = NULL;