/g/ - syscall of the day: syslog - Technology

Anonymous

syscall of the day: syslog 03/24/26(Tue)10:29:32 No.108444267

File: logician-romance-v0-07uag(...).png (10 KB, 391x455)

syscall of the day: syslog Anonymous 03/24/26(Tue)10:29:32 No.108444267 Archived

previous: >>108436379
#define __NR_syslog                103
https://man7.org/linux/man-pages/man2/syslog.2.html

tl;dr:
it's basically dmesg

or rather, dmesg wraps syslog
https://man7.org/linux/man-pages/man1/dmesg.1.html

it lets you read kernel log messages, filter by priority level, etc. as anyone who has ever customized their own kernel knows, these log messages are invaluable

this was pretty funny to me:
>From the very start, people noted that it is unfortunate that a system call and a library routine of the same name are entirely different animals.

relevant resources:
man man
man syscalls
https://man7.org/linux/man-pages/
https://linux.die.net/man/
https://elixir.bootlin.com/linux/
https://elixir.bootlin.com/musl/
https://elixir.bootlin.com/glibc/

Anonymous
03/24/26(Tue)11:02:57 No.108444436

Anonymous 03/24/26(Tue)11:02:57 No.108444436

You mean any unprivileged application can just emit an arbitrary amount of data that will be stored in a privileged location? Sounds like a security issue.

Anonymous
03/24/26(Tue)11:06:46 No.108444459

Anonymous 03/24/26(Tue)11:06:46 No.108444459

>>108444436
did you even read the manpage? >:(

All commands except 3 and 10 require privilege.  In Linux kernels
       before Linux 2.6.37, command types 3 and 10 are allowed to
       unprivileged processes; since Linux 2.6.37, these commands are
       allowed to unprivileged processes only if
       /proc/sys/kernel/dmesg_restrict has the value 0.  Before Linux
       2.6.37, "privileged" means that the caller has the CAP_SYS_ADMIN
       capability.  Since Linux 2.6.37, "privileged" means that the
       caller has either the CAP_SYS_ADMIN capability (now deprecated for
       this purpose) or the (new) CAP_SYSLOG capability.