mirrors/musl
1
0
Fork 0
mirror of https://git.musl-libc.org/git/musl synced 2025-01-05 06:14:25 +03:00
Code Issues Packages Projects Releases Wiki Activity

use kernel-provided AT_MINSIGSTKSZ for sysconf(_SC_[MIN]SIGSTKSZ)

Browse Source 
use the legacy constant values if the kernel does not provide
AT_MINSIGSTKSZ (__getauxval will return 0 in this case) and as a
safety check if something is wrong and the provided value is less than
the legacy constant.

sysconf(_SC_SIGSTKSZ) returns SIGSTKSZ adjusted for the difference
between the legacy constant MINSIGSTKSZ and the runtime value, so that
the working space the application has on top of the minimum remains
invariant under changes to the minimum.
This commit is contained in:
Rich Felker 2022-08-26 11:34:46 -04:00
parent 25340a9337
commit 996b6154b2
1 changed files with 12 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

14
src/conf/sysconf.c
View File

@ -4,6 +4,7 @@
#include <sys/resource.h>
#include <signal.h>
#include <sys/sysinfo.h>
#include <sys/auxv.h>
#include "syscall.h"
#include "libc.h"
@ -19,6 +20,8 @@
#define JT_AVPHYS_PAGES JT(9)
#define JT_ZERO JT(10)
#define JT_DELAYTIMER_MAX JT(11)
#define JT_MINSIGSTKSZ JT(12)
#define JT_SIGSTKSZ JT(13)
#define RLIM(x) (-32768|(RLIMIT_ ## x))
@ -166,8 +169,8 @@ long sysconf(int name)
[_SC_THREAD_ROBUST_PRIO_INHERIT] = -1,
[_SC_THREAD_ROBUST_PRIO_PROTECT] = -1,
[_SC_MINSIGSTKSZ] = MINSIGSTKSZ,
[_SC_SIGSTKSZ] = SIGSTKSZ,
[_SC_MINSIGSTKSZ] = JT_MINSIGSTKSZ,
[_SC_SIGSTKSZ] = JT_SIGSTKSZ,
};
if (name >= sizeof(values)/sizeof(values[0]) || !values[name]) {
@ -215,6 +218,13 @@ long sysconf(int name)
mem *= si.mem_unit;
mem /= PAGE_SIZE;
return (mem > LONG_MAX) ? LONG_MAX : mem;
case JT_MINSIGSTKSZ & 255:
case JT_SIGSTKSZ & 255: ;
long val = __getauxval(AT_MINSIGSTKSZ);
if (val < MINSIGSTKSZ) val = MINSIGSTKSZ;
if (values[name] == JT_SIGSTKSZ)
val += SIGSTKSZ - MINSIGSTKSZ;
return val;
case JT_ZERO & 255:
return 0;
}