PawletOS/external_libudev-zero
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udev_device.c: correctly handle multiline sysattrs

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Changed arbitrary size of sysattr to PAGESIZE[0]. Not sure about binary
sysattrs because they may be > PAGESIZE. Either way, we need dynamic
allocation to handle them.

Trim only trailing newlines, not the first one. Now content of the
sysattr not getting truncated. By the way, do we need to trim carrige
return '\r' too?

[0] https://www.kernel.org/doc/Documentation/filesystems/sysfs.txt

> The buffer will always be PAGE_SIZE bytes in length. On i386, this
  is 4096.

Fixes #25
This commit is contained in:
illiliti
2021-05-21 05:49:41 +03:00
parent 1fd071f24e
commit a885b93c3c
1 changed files with 9 additions and 8 deletions
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udev_device.c
+9 -8
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@@ -212,11 +212,10 @@ const char *udev_device_get_property_value(struct udev_device *udev_device, cons
const char *udev_device_get_sysattr_value(struct udev_device *udev_device, const char *sysattr)
{
struct udev_list_entry *list_entry;
char data[1024], path[PATH_MAX];
char data[PAGESIZE], path[PATH_MAX];
struct stat st;
size_t len;
FILE *file;
char *pos;
if (!udev_device || !sysattr) {
return NULL;
@@ -240,19 +239,21 @@ const char *udev_device_get_sysattr_value(struct udev_device *udev_device, const
return NULL;
}
len = fread(data, 1, sizeof(data), file);
// TODO dynamic allocation of data
len = fread(data, 1, sizeof(data)-1, file);
if (len != sizeof(data) && ferror(file)) {
if (len != sizeof(data)-1 && ferror(file)) {
fclose(file);
return NULL;
}
if ((pos = memchr(data, '\n', len))) {
len = pos - data;
}
fclose(file);
data[len] = '\0';
while (len-- > 0 && data[len] == '\n') {
data[len] = '\0';
}
list_entry = udev_list_entry_add(&udev_device->sysattrs, sysattr, data, 0);
return udev_list_entry_get_value(list_entry);
}