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libc: implement getppid() reading /proc/$pid/ppid instead of /dev/ppid

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The devcons driver is really the wrong place to
serve per process information.
This commit is contained in:
cinap_lenrek 2020-12-19 15:15:38 +01:00
parent d919ad3b5e
commit 672cf179a1
3 changed files with 21 additions and 27 deletions
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17
sys/src/libc/9sys/getppid.c
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@ -4,14 +4,15 @@
int
getppid(void)
{
char b[20];
char buf[32];
int f;
memset(b, 0, sizeof(b));
f = open("/dev/ppid", OREAD|OCEXEC);
if(f >= 0) {
read(f, b, sizeof(b));
close(f);
}
return atol(b);
snprint(buf, sizeof(buf), "/proc/%lud/ppid", (ulong)getpid());
f = open(buf, OREAD|OCEXEC);
if(f < 0)
return 0;
memset(buf, 0, sizeof(buf));
read(f, buf, sizeof(buf)-1);
close(f);
return atol(buf);
}