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Fix punctuation to avoid confusion (Not easy in a question about the close parenthesis character).
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Dannie
Dannie
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In linux procfs, /proc/<pid>/stat includes as its second argument the name of the process in parentheses. As far as I can tell (by experimentation) this is unescaped. For example, I have been able to create the following

$ gcc test.c -o 'hello) (world' ... $ cat /proc/9115/stat 9115 (hello) (world) S 8282 9115 ...

(similarly gcc test.c -o 'name) S 42 23' can allow processes to accidentally or deliberately create fields which will probably mislead naive parsers).

I need to "get at" one of the later fields so need a correct way of skipping this field. I've searched for quite a while to find a reliable way of parsing this line, but have failed to find a canonical question or example.

However, from what I can tell ) is not valid in any field to the right of this field, so a scan from right to left to find the rightmost ) should correctly delimit this second field. Is this correct? This seems a little flaky to me (what if some new field allows ) at a later date)? Is there a better way to parse this file that I've overlooked.?

In linux procfs, /proc/<pid>/stat includes as its second argument the name of the process in parentheses. As far as I can tell (by experimentation) this is unescaped. For example, I have been able to create the following

$ gcc test.c -o 'hello) (world' ... $ cat /proc/9115/stat 9115 (hello) (world) S 8282 9115 ...

(similarly gcc test.c -o 'name) S 42 23' can allow processes to accidentally or deliberately create fields which mislead naive parsers.

I need to "get at" one of the later fields so need a correct way of skipping this field. I've searched for quite a while to find a reliable way of parsing this line, but have failed to find a canonical question or example.

However, from what I can tell ) is not valid in any field to the right of this field, so a scan from right to left to find the rightmost ) should correctly delimit this second field. Is this correct? This seems a little flaky to me (what if some new field allows ) at a later date)? Is there a better way to parse this file that I've overlooked.

In linux procfs, /proc/<pid>/stat includes as its second argument the name of the process in parentheses. As far as I can tell (by experimentation) this is unescaped. For example, I have been able to create the following

$ gcc test.c -o 'hello) (world' ... $ cat /proc/9115/stat 9115 (hello) (world) S 8282 9115 ...

(similarly gcc test.c -o 'name) S 42 23' can allow processes to accidentally or deliberately create fields which will probably mislead naive parsers).

I need to "get at" one of the later fields so need a correct way of skipping this field. I've searched for quite a while to find a reliable way of parsing this line, but have failed to find a canonical question or example.

However, from what I can tell ) is not valid in any field to the right of this field, so a scan from right to left to find the rightmost ) should correctly delimit this second field. Is this correct? This seems a little flaky to me (what if some new field allows ) at a later date)? Is there a better way to parse this file that I've overlooked?

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Dannie
Dannie
  • 213
  • 2
  • 7

Way to unambiguously parse /proc/<pid>/stat (given arbitrary contents of name field)

In linux procfs, /proc/<pid>/stat includes as its second argument the name of the process in parentheses. As far as I can tell (by experimentation) this is unescaped. For example, I have been able to create the following

$ gcc test.c -o 'hello) (world' ... $ cat /proc/9115/stat 9115 (hello) (world) S 8282 9115 ...

(similarly gcc test.c -o 'name) S 42 23' can allow processes to accidentally or deliberately create fields which mislead naive parsers.

I need to "get at" one of the later fields so need a correct way of skipping this field. I've searched for quite a while to find a reliable way of parsing this line, but have failed to find a canonical question or example.

However, from what I can tell ) is not valid in any field to the right of this field, so a scan from right to left to find the rightmost ) should correctly delimit this second field. Is this correct? This seems a little flaky to me (what if some new field allows ) at a later date)? Is there a better way to parse this file that I've overlooked.