dockapps/wmhdplop/devnames.c
Doug Torrance 8c43b61e0d wmhdplop: Find disk device after /run transition
Patch by Andre Beck <beck@ibh.de> to fix Debian bug #657882.

After the recent /run transition, which also finally turned /etc/mtab into
a symlink to /proc/mounts, *hdplop (both incarnations) may fail to find a
single disk device automatically. This is likely due to the root device
now being exposed as mounted on /dev/disk/by-uuid/$UUID whereas the
former /etc/mtab as written by mount still contained a device name as
taken from /etc/fstab, which in my case could be parsed by *hdplop. It's
unclear if this wouldn't have hit other environments earlier depending
on their fstab contents, I just assume for now that I'm one of the
remaining handful of users of this tool ;)

The fundamental issue is of course the rather crude code in devnames.c's
device_id_from_name() which tries to manually resolve device symlinks,
but cannot possibly work with any symlink except those located directly
in /dev - symlinks in subdirectories of /dev will fail.

Impact on wmhdplop: Doesn't start except when called explicitely with
some "-d /dev/sda" or such option.

Impact on gkrellm-hdplop: Starts but is dazed and confused, leaving a
black window in gkrellm. Clicking on the black window will then crash
gkrellm, as it hits an assertion that the device list cannot be empty.

I've prepared a small patch that makes *hdplop work again for me, the
patch replaces the broken manual symlink resolving by a simple call
to realpath(3), hopefully not breaking other stuff. I refrained from
doing any more changes to the code, even though it looks like it needs
some love. Upstream seems to have lost interest five years ago, though...

So, without much further ado, here's my crude fix:

Don't look too closely, specifically on the strncpy(3) stuff, but I felt
this is still better than abusing snprintf(3) like the original code does
some lines above, and as I said, starting to really fix things here looks
like a bottomless pit...

Thanks,
Andre.

https://bugs.debian.org/657882
https://sources.debian.net/src/wmhdplop/0.9.9-5/debian/patches/
  find-disk-device.patch/
2016-11-24 15:43:12 +00:00

267 lines
7.4 KiB
C

#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <string.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <linux/major.h>
#include <ctype.h>
#include "global.h"
#include "devnames.h"
static DiskList *dlist = NULL;
const char *stripdev(const char *s) {
if (strncmp(s,"/dev",4) == 0) s+= 4;
if (s[0] == '/') s++;
return s;
}
DiskList *find_dev(unsigned major, unsigned minor) {
DiskList *dl;
for (dl = dlist; dl; dl = dl->next) {
if (dl->major == major && dl->minor == minor) return dl;
}
return NULL;
}
DiskList *find_id(int hd_id, int part_id) {
DiskList *dl;
for (dl = dlist; dl; dl = dl->next) {
if (((dl->hd_id == hd_id) || hd_id == -1) &&
((dl->part_id == part_id) || part_id == -1)) return dl;
}
return NULL;
}
/*
DiskList *find_dev_by_name(const char *name) {
DiskList *dl;
const char *sname = stripdev(name);
for (dl = dlist; dl; dl = dl->next) {
if (strcmp(sname, dl->name)==0) return dl;
}
return NULL;
}*/
DiskList *next_hd_in_list(DiskList *prev) {
DiskList *dl = (prev ? prev->next : dlist);
while (dl && IS_PARTITION(dl)) dl = dl->next;
return dl;
}
DiskList *first_hd_in_list() {
return next_hd_in_list(NULL);
}
DiskList *first_dev_in_list() {
return dlist;
}
int nb_hd_in_list() {
int i=0;
DiskList *dl;
for (dl = first_hd_in_list(); dl; dl = next_hd_in_list(dl)) ++i;
return i;
}
int nb_dev_in_list() {
int i=0;
DiskList *dl;
for (dl = dlist; dl; dl = dl->next) ++i;
return i;
}
/*int is_partition_name(const char *name) {
int l = strlen(name);
if (l && name[l-1] >= '0' && name[l-1] <= '9') return 1;
return 0;
}
*/
static const char *to_num_(unsigned minor) {
static char id[16];
if (minor == 0) return "";
else snprintf(id,16,"%d",minor);
return id;
}
int device_info(unsigned major, unsigned minor, char *name, int *hd_id, int *part_id) {
switch(major) {
#ifdef SCSI_DISK0_MAJOR
case (SCSI_DISK0_MAJOR):
#else
case (SCSI_DISK_MAJOR):
#endif
if (name) sprintf(name, "sd%c%s", "abcdefghijklmnop"[(minor)/16], to_num_(minor%16));
if (hd_id) *hd_id = (minor)/16;
if (part_id) *part_id = minor%16;
return 1;
case IDE0_MAJOR:
if (name) sprintf(name, "hd%c%s", "ab"[(minor)/64], to_num_(minor%64));
if (hd_id) *hd_id = 100 + (minor)/64;
if (part_id) *part_id = minor%64;
return 2;
case IDE1_MAJOR:
if (name) sprintf(name, "hd%c%s", "cd"[(minor)/64], to_num_(minor%64));
if (hd_id) *hd_id = 200 + (minor)/64;
if (part_id) *part_id = minor%64;
return 3;
#ifdef IDE2_MAJOR
case IDE2_MAJOR:
if (name) sprintf(name, "hd%c%s", "ef"[(minor)/64], to_num_(minor%64));
if (hd_id) *hd_id = 300 + (minor)/64;
if (part_id) *part_id = minor%64;
return 4;
#endif
#ifdef IDE3_MAJOR
case IDE3_MAJOR:
if (name) sprintf(name, "hd%c%s", "gh"[(minor)/64], to_num_(minor%64));
if (hd_id) *hd_id = 400 + (minor)/64;
if (part_id) *part_id = minor%64;
return 5;
#endif
#ifdef IDE4_MAJOR
case IDE4_MAJOR:
if (name) sprintf(name, "hd%c%s", "ij"[(minor)/64], to_num_(minor%64));
if (hd_id) *hd_id = 400 + (minor)/64;
if (part_id) *part_id = minor%64;
return 6;
#endif
#ifdef IDE5_MAJOR
case IDE5_MAJOR:
if (name) sprintf(name, "hd%c%s", "kl"[(minor)/64], to_num_(minor%64));
if (hd_id) *hd_id = 400 + (minor)/64;
if (part_id) *part_id = minor%64;
return 7;
#endif
#ifdef IDE6_MAJOR
case IDE6_MAJOR:
if (name) sprintf(name, "hd%c%s", "mn"[(minor)/64], to_num_(minor%64));
if (hd_id) *hd_id = 400 + (minor)/64;
if (part_id) *part_id = minor%64;
return 8;
#endif
#ifdef MD_MAJOR
case (MD_MAJOR):
if (name) sprintf(name, "md%s", to_num_(minor));
if (hd_id) *hd_id = 400 + minor;
if (part_id) *part_id = 0;
return 9;
#endif
}
if (name) *name = 0;
if (hd_id) *hd_id = -1;
if (part_id) *part_id = -1;
return 0;
}
int short_name_for_device(unsigned major, unsigned minor, char *name) {
return device_info(major,minor,name,NULL,NULL);
}
int is_partition(unsigned major, unsigned minor) {
int part_id;
if (!device_info(major,minor,NULL,NULL,&part_id)) return 0;
return (part_id != 0);
}
int device_id_from_name(const char *devname__, unsigned *pmajor, unsigned *pminor) {
if (strlen(devname__)>=512) return -1;
char *devname_, devname[512];
devname_ = str_substitute(devname__, "/dev/mapper", "/dev");
struct stat stat_buf;
BLAHBLAH(1,printf("looking for %s in /dev..\n", devname_));
if (devname_[0] != '/') snprintf(devname,512,"/dev/%s", devname_);
else snprintf(devname,512,"%s",devname_);
free(devname_); devname_ = 0;
if (lstat(devname,&stat_buf)) { BLAHBLAH(1,perror(devname)); return -1; }
if (S_ISLNK(stat_buf.st_mode)) {
devname_ = realpath(devname, NULL);
if(!devname_) { BLAHBLAH(1,perror(devname)); return -1; }
strncpy(devname, devname_, 512); devname[511] = 0;
free(devname_);
if (stat(devname,&stat_buf)) { BLAHBLAH(1,perror(devname)); return -1; }
}
if (!S_ISBLK(stat_buf.st_mode)) {
fprintf(stderr, "%s is not a block device..\n", devname);
return -2;
}
*pmajor = major(stat_buf.st_rdev);
*pminor = minor(stat_buf.st_rdev);
return 0;
}
/* add a hard-drive if it is a regular ide/scsi/md disk/partition, or return NULL */
static DiskList *create_device(unsigned major, unsigned minor, const char *mtab_name) {
DiskList *dl;
char dev_path[512];
ALLOC_OBJ(dl);
if (mtab_name && strlen(mtab_name)) dl->name = strdup(mtab_name);
else {
char s[512]; short_name_for_device(major,minor,s); dl->name = strdup(s);
}
BLAHBLAH(1, printf("create_device(major=%d, minor=%d, mtab_name=%s) : name=%s\n", major,minor,mtab_name,dl->name));
dl->major = major; dl->minor = minor;
if (device_info(major,minor,dev_path,&dl->hd_id,&dl->part_id) == 0) {
BLAHBLAH(1, printf("(%d,%d) is not a known disc type..\n", major,minor));
free(dl); return NULL;
}
dl->dev_path = malloc(strlen(dev_path)+6); assert(dl->dev_path);
sprintf(dl->dev_path, "/dev/%s", dev_path);
dl->next = NULL;
if (dl->part_id == 0)
dl->enable_hddtemp = 1;
return dl;
}
/* add a device (after checking that it is a known device type) */
int add_device_by_name(const char *devname, const char *mtab_name) {
unsigned major, minor;
BLAHBLAH(1,printf("add_device_by_name(%s,%s)\n", devname, mtab_name));
if (device_id_from_name(devname, &major, &minor) != 0) return -1;
return add_device_by_id(major,minor,mtab_name);
}
/* add a device (after checking that it is a known device type) */
int add_device_by_id(unsigned major, unsigned minor, const char *mtab_name) {
DiskList *dl, *next, *prev;
BLAHBLAH(1,printf("add_device_by_id(%d,%d,%s)\n", major, minor,mtab_name));
/* already known ? */
if (find_dev(major,minor)) return -1;
/* check for known ide/scsi/md disks and then create */
dl = create_device(major, minor, mtab_name); if (!dl) return -1;
for (next = dlist, prev = NULL; next; next=next->next) {
if (dl->hd_id > next->hd_id || (dl->hd_id == next->hd_id && dl->part_id > next->part_id)) break;
prev = next;
}
if (prev == NULL) {
dl->next = dlist; dlist = dl;
} else {
dl->next = prev->next; prev->next = dl;
}
return 0;
}
strlist *swaplst = NULL;
void add_swap(const char *swapdev) {
swaplst = strlist_ins(swaplst, swapdev);
}
strlist *swap_list() {
return swaplst;
}