cmd: import pstree from 9front

This commit is contained in:
Giacomo Tesio 2017-11-07 00:52:05 +01:00
parent 8c5dff6c0b
commit fc2e066ca0
2 changed files with 185 additions and 0 deletions

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@ -40,6 +40,7 @@
"p.c",
"pipefile.c",
"ps.c",
"pstree.c",
"pwd.c",
"ramfs.c",
"rm.c",

184
sys/src/cmd/pstree.c Normal file
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@ -0,0 +1,184 @@
#include <u.h>
#include <lib9.h>
#include <bio.h>
typedef struct Proc Proc;
struct Proc {
int pid;
Proc *first, *parent, *next;
Proc *hash;
};
Proc *hash[1024];
Rune buf[512];
Biobuf bout;
Proc *
getproc(int pid)
{
Proc *p;
for(p = hash[pid % nelem(hash)]; p; p = p->hash)
if(p->pid == pid)
return p;
return nil;
}
void
addproc(int pid)
{
Proc *p;
p = mallocz(sizeof(*p), 1);
if(p == nil)
sysfatal("malloc: %r");
p->pid = pid;
p->hash = hash[pid % nelem(hash)];
hash[pid % nelem(hash)] = p;
}
int
theppid(int pid)
{
char b[128];
int fd, ppid;
ppid = 0;
snprint(b, sizeof(b), "%d/ppid", pid);
fd = open(b, OREAD);
if(fd >= 0){
memset(b, 0, sizeof b);
if(read(fd, b, sizeof b-1) >= 0){
ppid = atoi(b);
if(ppid < 0)
ppid = 0;
}
close(fd);
}
return ppid;
}
void
addppid(int pid)
{
Proc *p, *par, **l;
p = getproc(pid);
par = getproc(theppid(pid));
if(par == nil)
par = getproc(0);
p->parent = par;
for(l = &par->first; *l; l = &((*l)->next))
if((*l)->pid > pid)
break;
p->next = *l;
*l = p;
}
void
addprocs(void)
{
int fd, rc, i;
Dir *d;
fd = open(".", OREAD);
if(fd < 0)
sysfatal("open: %r");
rc = dirreadall(fd, &d);
if(rc < 0)
sysfatal("dirreadall: %r");
close(fd);
for(i = 0; i < rc; i++)
if(d[i].mode & DMDIR)
addproc(atoi(d[i].name));
for(i = 0; i < rc; i++)
if(d[i].mode & DMDIR)
addppid(atoi(d[i].name));
free(d);
}
int
readout(char *file)
{
int fd, rc, i, n;
char b[512];
fd = open(file, OREAD);
if(fd < 0)
return -1;
n = 0;
while((rc = read(fd, b, sizeof b)) > 0){
for(i=0; i<rc; i++)
if(b[i] == '\n')
b[i] = ' ';
n += Bwrite(&bout, b, rc);
}
close(fd);
return n;
}
void
printargs(int pid)
{
char b[128], *p;
int fd;
snprint(b, sizeof(b), "%d/args", pid);
if(readout(b) > 0)
return;
snprint(b, sizeof(b), "%d/status", pid);
fd = open(b, OREAD);
if(fd >= 0){
memset(b, 0, sizeof b);
if(read(fd, b, 27) > 0){
p = b + strlen(b);
while(p > b && p[-1] == ' ')
*--p = 0;
Bprint(&bout, "%s", b);
}
close(fd);
}
}
void
descend(Proc *p, Rune *r)
{
Rune last;
Proc *q;
last = *--r;
*r = last == L' ' ? L'' : L'';
if(p->pid != 0){
Bprint(&bout, "%-11d %S", p->pid, buf);
printargs(p->pid);
Bprint(&bout, "\n");
}
*r = last;
*++r = L'';
for(q = p->first; q; q = q->next) {
if(q->next == nil)
*r = L' ';
descend(q, r + 1);
}
*r = 0;
}
void
printprocs(void)
{
descend(getproc(0), buf);
}
void
main()
{
Binit(&bout, 1, OWRITE);
if(chdir("/proc")==-1)
sysfatal("chdir: %r");
addproc(0);
addprocs();
printprocs();
exits(0);
}