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I need to modify the process name of my program in C language.
I precise, this is not the name of a thread that I want to change.
I want to change the name of my program, but the only solution I found, is to modify the value of argv[0].
I also found another solution with prctl(PR_SET_NAME, "newname"), but this solution doesn't work.

Alexis Wilke
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Jérémy Magrin
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  • possible duplicate of [How to name a thread in Linux?](http://stackoverflow.com/questions/778085/how-to-name-a-thread-in-linux) – sehe Apr 23 '13 at 09:33
  • _"The documentation says PR_SET_NAME sets the process name; but that documentation is wrong - it does actually set the thread name. Now "top" and "ps -L" show the thread name."_ -- [user9876 Apr 22 '09 at 17:39](http://stackoverflow.com/questions/778085/how-to-name-a-thread-in-linux#comment588964_778124) – sehe Apr 23 '13 at 09:34
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    PR_SET_NAME flag is supported since Linux 2.6.9 – akhil Apr 23 '13 at 09:55

2 Answers2

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The differences between invoking prctl and modify argv[0] are:

  • modify argv[0] changes information in /proc/$pid/cmdline
  • invoking prctl(PR_SET_NAME) changes information in /proc/$pid/status

That means you will get difference name of your process issuing ps -a and ps -ax.

If you expects same process name for different arguments while executing ps, you can do them both (i.e., change argv[0] and invoke prctl).

Hope the answer helps.

Caterpillar
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Wayne
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-2

try this:

char *process_name = "aaa\0";
memcpy((void *)argv[0], process_name, sizeof(process_name));

/* explain： The space allocated for argv[0] could be smaller than the name that you want to give and then you will be overwritting some other unrelated memory. argv[0] size could be just 2 and if your process name is "averylongprocessname" you will be overflowing argv[0]. You need to strlen(argv[0]) and use that in memcpy. thx @ecerulm

*/

lingyfh
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    I think that the \0 is unnecessary - isn't it already silently appended to a literal string of characters? – Chap Apr 30 '14 at 04:09
  • @Chap: it's true for `strcpy`, not for `memcpy`. – Dmytro Sirenko Sep 01 '14 at 18:06
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    Seems that you have to overwrite all characters of origin `argv[0]`, is it true? So you can't have process names bigger than original name – Luca Marturana Feb 24 '15 at 10:05
  • The space allocated for `argv[0]` could be smaller than the name that you want to give and then you will be overwritting some other unrelated memory. `argv[0]` size could be just 2 and if your process name is "averylongprocessname" you will be overflowing `argv[0]`. You need to `strlen(argv[0])` and use that in `memcpy`. – RubenLaguna Mar 09 '15 at 10:21
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    The `\0` is unnecessary. Also, `sizeof` is incorrect here as it would return the size of a pointer (typically 4 or 8 bytes). You want something more like `strncpy(argv[0], process_name, strlen(process_name)` or `memcpy(argv[0], process_name, (strlen(argv[0]) < strlen(process_name)+1) ? strlen(argv[0]) : strlen(process_name)+1)` – craig65535 Mar 20 '15 at 17:07