894452 - b2g-info won't correctly parse comm which has ) in it

Status: RESOLVED WONTFIX

(Firefox OS Graveyard :: General, defect)

Description

[Dave Hylands [:dhylands]]

The fscanf in process.cpp won't work properly if the comm contains a ) character.

For example, I created a script which I called a)b which did:

#/system/bin/sh
sleep 300

and executed it. Then the stat line looked like:

127|root@android:/data/local/tmp # cat /proc/2204/stat                         
2204 (a)c) S 2154 2204 2154 34817 2210 4194304 167 0 0 0 0 1 0 0 20 0 1 0 6137685 802816 98 4294967295 32768 176196 3197381536 3197380840 1074061460 0 0 0 134337775 3221474612 0 0 17 0 0 0 0 0 0

So, my conclusion is that the only correct way to parse out the comm is start at the beginning of the string and look for '('. Then start 17 characters after that and scan backwards looking for ')'.

comm will be whatever is between ( and ). You can then do a sscanf on everything after the ) to parse the remaining fields.

I don't consider this to be a high priority, but basically, if an app were to ever contain a ) in its name, then b2g-info wouldn't grab the correct information.

Comment 1

[Justin Lebar (not reading bugmail)]

> I don't consider this to be a high priority, but basically, if an app were to ever 
> contain a ) in its name, then b2g-info wouldn't grab the correct information.

Such as the app named "(Preallocated app)".

Although we can definitely change that.  :)

Comment 2

[Alan Huang]

(In reply to Dave Hylands [:dhylands] from comment #0)
> So, my conclusion is that the only correct way to parse out the comm is
> start at the beginning of the string and look for '('. Then start 17
> characters after that and scan backwards looking for ')'.

Will it be easier if we read the comm from /proc/[pid]/comm ?

Comment 3

[Dave Hylands [:dhylands]]

We need the rest of the information from the stat line, so we might as well just grab it from there.

I wrote some code in dom/system/OpenFileFinder.cpp which parses the comm out using:

  char *closeParen = strrchr(stat, ')');
  if (!closeParen) {
    return;
  }
  char *openParen = strchr(stat, '(');
  if (!openParen) {
    return;
  }
  if (openParen >= closeParen) {
    return;
  }
  nsDependentCSubstring comm(&openParen[1], closeParen - openParen - 1);

and then you can use sscanf to grab the rest of the stat stuff using closeParen as your starting place.

Comment 4

[BMO Automation]

Firefox OS is not being worked on