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// SPDX-License-Identifier: GPL-2.0-or-later
#include "common.h"
#define BUFLEN 64
const char *const block_dir_name = "/sys/class/block";
struct devpath {
char prefix[5];
char device[11];
};
struct partname_volume {
struct volume v;
union {
char devpathstr[16];
struct devpath devpath;
} dev;
union {
char devpathstr[16];
struct devpath devpath;
} parent_dev;
};
static struct driver partname_driver;
static int partname_volume_identify(struct volume *v)
{
struct partname_volume *p = container_of(v, struct partname_volume, v);
int ret = FS_NONE;
FILE *f;
f = fopen(p->dev.devpathstr, "r");
if (!f)
return ret;
ret = block_file_identify(f, 0);
fclose(f);
return ret;
}
static int partname_volume_init(struct volume *v)
{
struct partname_volume *p = container_of(v, struct partname_volume, v);
char voldir[BUFLEN];
unsigned int volsize;
snprintf(voldir, sizeof(voldir), "%s/%s", block_dir_name, p->dev.devpath.device);
if (read_uint_from_file(voldir, "size", &volsize))
return -1;
v->type = BLOCKDEV;
v->size = volsize << 9; /* size is returned in sectors of 512 bytes */
v->blk = p->dev.devpathstr;
return block_volume_format(v, 0, p->parent_dev.devpathstr);
}
/* adapted from procd/utils.c -> should go to libubox */
static char* get_var_from_file(const char* filename, const char* name, char* out, int len)
{
char line[1024], *c, *sptr;
int fd = open(filename, O_RDONLY);
if (fd == -1)
return NULL;
ssize_t r = read(fd, line, sizeof(line) - 1);
close(fd);
if (r <= 0)
return NULL;
line[r] = 0;
for (c = strtok_r(line, " \t\n", &sptr); c;
c = strtok_r(NULL, " \t\n", &sptr)) {
char *sep = strchr(c, '=');
if (sep == NULL)
continue;
ssize_t klen = sep - c;
if (strncmp(name, c, klen) || name[klen] != 0)
continue;
strncpy(out, &sep[1], len);
out[len-1] = '\0';
return out;
}
return NULL;
}
static char *rootdevname(char *devpath) {
int l;
l = strlen(devpath) - 1;
/* strip partition suffix from root=/dev/... string */
while (l > 0 && (devpath[l] >= '0' && devpath[l] <= '9'))
--l;
if (devpath[l] != 'p')
++l;
devpath[l] = '\0';
return basename(devpath);
}
static struct volume *partname_volume_find(char *name)
{
struct partname_volume *p;
char ueventgstr[BUFLEN];
char namebuf[BUFLEN];
char rootparam[BUFLEN];
char *rootdev = NULL, *devname, *tmp;
int j;
bool found = false;
glob_t gl;
if (get_var_from_file("/proc/cmdline", "fstools_ignore_partname", rootparam, sizeof(rootparam))) {
if (!strcmp("1", rootparam))
return NULL;
}
if (get_var_from_file("/proc/cmdline", "root", rootparam, sizeof(rootparam)) && rootparam[0] == '/') {
rootdev = rootdevname(rootparam);
/* find partition on same device as rootfs */
snprintf(ueventgstr, sizeof(ueventgstr), "%s/%s/*/uevent", block_dir_name, rootdev);
} else {
/* no useful 'root=' kernel cmdline parameter, find on any block device */
snprintf(ueventgstr, sizeof(ueventgstr), "%s/*/uevent", block_dir_name);
}
if (!glob(ueventgstr, GLOB_NOESCAPE, NULL, &gl))
for (j = 0; j < gl.gl_pathc; j++) {
if (!get_var_from_file(gl.gl_pathv[j], "PARTNAME", namebuf, sizeof(namebuf)))
continue;
if (!strncmp(namebuf, name, sizeof(namebuf))) {
found = 1;
break;
}
}
if (!found)
return NULL;
devname = gl.gl_pathv[j];
tmp = strrchr(devname, '/');
if (!tmp)
return NULL;
*tmp = '\0';
devname = strrchr(devname, '/') + 1;
p = calloc(1, sizeof(*p));
memcpy(p->dev.devpath.prefix, "/dev/", sizeof(p->dev.devpath.prefix));
strncpy(p->dev.devpath.device, devname, sizeof(p->dev.devpath.device) - 1);
p->dev.devpath.device[sizeof(p->dev.devpath.device)-1] = '\0';
memcpy(p->parent_dev.devpath.prefix, "/dev/", sizeof(p->parent_dev.devpath.prefix));
if (rootdev)
strncpy(p->parent_dev.devpath.device, rootdev, sizeof(p->parent_dev.devpath.device) - 1);
else
strncpy(p->parent_dev.devpath.device, rootdevname(devname), sizeof(p->parent_dev.devpath.device) - 1);
p->parent_dev.devpath.device[sizeof(p->parent_dev.devpath.device)-1] = '\0';
p->v.drv = &partname_driver;
p->v.blk = p->dev.devpathstr;
p->v.name = name;
return &p->v;
}
static struct driver partname_driver = {
.name = "partname",
.find = partname_volume_find,
.init = partname_volume_init,
.identify = partname_volume_identify,
};
DRIVER(partname_driver);
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