1 /* ps.c - show process list
2  *
3  * Copyright 2015 Rob Landley <rob@landley.net>
4  *
5  * See http://pubs.opengroup.org/onlinepubs/9699919799/utilities/ps.html
6  * And http://kernel.org/doc/Documentation/filesystems/proc.txt Table 1-4
7  * And linux kernel source fs/proc/array.c function do_task_stat()
8  *
9  * Deviations from posix: no -n to specify an alternate /etc/passwd (??!?)
10  * Posix says default output should have field named "TTY" but if you "-o tty"
11  * the same field should be called "TT" which is _INSANE_ and I'm not doing it.
12  * It also says that -o "args" and "comm" should behave differently but use
13  * the same title, which is not the same title as the default output. No.
14 
15 USE_PS(NEWTOY(ps, "aAdeflo*[!ol][+Ae]", TOYFLAG_USR|TOYFLAG_BIN))
16 
17 config PS
18   bool "ps"
19   default n
20   help
21     usage: ps [-Aade] [-fl] [-gG GROUP] [-o FIELD] [-p PID] [-t TTY] [-u USER]
22 
23     List processes.
24 
25     -A	All processes
26     -a	Processes with terminals, except session leaders
27     -d	Processes that aren't session leaders
28     -e	Same as -A
29     -f	Full listing
30     -l	Long listing
31 
32     -g  Processes belonging to these session leaders
33     -G	Processes with these real group IDs
34     -o	Show FIELDS for each process
35     -p	select by PID
36     -t	select by TTY
37     -u	select by USER
38     -U	select by USER
39 
40      GROUP, FIELD, PID, TTY, and USER are comma separated lists.
41 
42     OUTPUT (-o) FIELDS:
43 
44       "UID", "PID", "PPID", "C", "PRI", "NI", "ADDR", "SZ",
45       "WCHAN", "STIME", "TTY", "TIME", "CMD", "COMMAND", "ELAPSED", "GROUP",
46       "%CPU", "PGID", "RGROUP", "RUSER", "USER", "VSZ"
47 
48       C    Processor utilization for scheduling
49       F    Process flags (PF_*) from linux source file include/sched.h
50            (in octal rather than hex because posix)
51       S    Process state:
52            R (running) S (sleeping) D (disk sleep) T (stopped)  t (tracing stop)
53            Z (zombie)  X (dead)     x (dead)       K (wakekill) W (waking)
54       PID  Process id
55       PPID Parent process id
56       PRI  Priority
57       UID  User id of process owner
58 
59     Default output is -o PID,TTY,TIME,CMD
60     With -f USER=UID,PID,PPID,C,STIME,TTY,TIME,CMD
61     With -l F,S,UID,PID,PPID,C,PRI,NI,ADDR,SZ,WCHAN,TTY,TIME,CMD
62 */
63 
64 #define FOR_ps
65 #include "toys.h"
66 
67 GLOBALS(
68   struct arg_list *o;
69 
70   unsigned width;
71   dev_t tty;
72   void *fields;
73   long uptime;
74 )
75 
76 /*
77   l l fl  a   fl   fl l  l  l    l  l     f     a   a    a
78   F S UID PID PPID C PRI NI ADDR SZ WCHAN STIME TTY TIME CMD
79   ruser user rgroup group pid ppid pgid pcpu vsz nice etime time tty comm args
80 
81   todo: thread support /proc/$d/task/%d/stat
82     man page: F flags mean...
83 */
84 
85 struct strawberry {
86   struct strawberry *next, *prev;
87   short which, len;
88   char title[];
89 };
90 
91 // dirtree callback.
92 // toybuf used as: 1024 /proc/$PID/stat, 1024 slot[], 2048 /proc/$PID/cmdline
do_ps(struct dirtree * new)93 static int do_ps(struct dirtree *new)
94 {
95   struct strawberry *field;
96   long long *slot = (void *)(toybuf+1024);
97   char *name, *s, state;
98   int nlen, i, fd, len, width = TT.width;
99 
100   if (!new->parent) return DIRTREE_RECURSE;
101   if (!(*slot = atol(new->name))) return 0;
102 
103   // name field limited to 256 bytes by VFS, plus 40 fields * max 20 chars:
104   // 1000-ish total, but some forced zero so actually there's headroom.
105   sprintf(toybuf, "%lld/stat", *slot);
106   if (!readfileat(dirtree_parentfd(new), toybuf, toybuf, 1024)) return 0;
107 
108   // parse oddball fields (name and state)
109   if (!(s = strchr(toybuf, '('))) return 0;
110   for (name = ++s; *s != ')'; s++) if (!*s) return 0;
111   nlen = s++-name;
112   if (1>sscanf(++s, " %c%n", &state, &i)) return 0;
113 
114   // parse numeric fields
115   for (len = 1; len<100; len++)
116     if (1>sscanf(s += i, " %lld%n", slot+len, &i)) break;
117 
118   // skip entries we don't care about.
119   if ((toys.optflags&(FLAG_a|FLAG_d)) && getsid(*slot)==*slot) return 0;
120   if ((toys.optflags&FLAG_a) && !slot[4]) return 0;
121   if (!(toys.optflags&(FLAG_a|FLAG_d|FLAG_A|FLAG_e)) && TT.tty!=slot[4])
122     return 0;
123 
124   for (field = TT.fields; field; field = field->next) {
125     char *out = toybuf+2048;
126 
127     // Default: unsupported (5 "C")
128     sprintf(out, "-");
129 
130     // PID, PPID, PRI, NI, ADDR, SZ
131     if (-1 != (i = stridx((char[]){3,4,6,7,8,9,0}, field->which)))
132       sprintf(out, ((1<<i)&0x10) ? "%llx" : "%lld",
133               slot[((char[]){0,2,16,17,22})[i]]>>(((1<<i)&0x20) ? 12 : 0));
134     // F
135     else if (!(i = field->which)) sprintf(out, "%llo", slot[7]);
136     // S
137     else if (i == 1)
138       sprintf(out, "%c", state);
139     // UID and USER
140     else if (i == 2 || i == 22) {
141       sprintf(out, "%d", new->st.st_uid);
142       if (i == 22) {
143         struct passwd *pw = getpwuid(new->st.st_uid);
144 
145         if (pw) out = pw->pw_name;
146       }
147     // WCHAN
148     } else if (i==10) {
149       sprintf(toybuf+512, "%lld/wchan", *slot);
150       readfileat(dirtree_parentfd(new), toybuf+512, out, 2047);
151 
152     // STIME
153     // TTY
154     } else if (i==12) {
155 
156       // Can we readlink() our way to a name?
157       for (i=0; i<3; i++) {
158         struct stat st;
159 
160         sprintf(toybuf+512, "%lld/fd/%i", *slot, i);
161         fd = dirtree_parentfd(new);
162         if (!fstatat(fd, toybuf+512, &st, 0) && S_ISCHR(st.st_mode)
163           && st.st_rdev == slot[4]
164           && 0<(len = readlinkat(fd, toybuf+512, out, 2047)))
165         {
166           out[len] = 0;
167           if (!strncmp(out, "/dev/", 5)) out += 5;
168 
169           break;
170         }
171       }
172 
173       // Couldn't find it, show major:minor
174       if (i==3) {
175         i = slot[4];
176         sprintf(out, "%d:%d", (i>>8)&0xfff, ((i>>12)&0xfff00)|(i&0xff));
177       }
178 
179     // TIME ELAPSED
180     } else if (i==13 || i==16) {
181       long seconds = (i==16) ? slot[20] : slot[11]+slot[12], ll = 60*60*24;
182 
183       seconds /= sysconf(_SC_CLK_TCK);
184       if (i==16) seconds = TT.uptime-seconds;
185       for (s = out, i = 0; i<4; i++) {
186         if (i>1 || seconds > ll)
187           s += sprintf(s, (i==3) ? "%02ld" : "%ld%c", seconds/ll, "-::"[i]);
188         seconds %= ll;
189         ll /= i ? 60 : 24;
190       }
191 
192 //16 "ELAPSED", "GROUP", "%CPU", "PGID", "RGROUP",
193 //21 "RUSER", -, "VSZ"
194 
195     // Command line limited to 2k displayable. We could dynamically malloc, but
196     // it'd almost never get used, querying length of a proc file is awkward,
197     // fixed buffer is nommu friendly... Wait for somebody to complain. :)
198     } else if (i == 14 || i == 15) {
199       int fd;
200 
201       len = 0;
202       sprintf(out, "%lld/cmdline", *slot);
203       fd = openat(dirtree_parentfd(new), out, O_RDONLY);
204 
205       if (fd != -1) {
206         if (0<(len = read(fd, out, 2047))) {
207           if (!out[len-1]) len--;
208           else out[len] = 0;
209           for (i = 0; i<len; i++) if (out[i] < ' ') out[i] = ' ';
210         }
211         close(fd);
212       }
213       if (len<1) sprintf(out, "[%.*s]", nlen, name);
214     }
215 
216     i = width<field->len ? width : field->len;
217     width -= printf(" %*.*s", i, field->next ? i : width, out);
218   }
219   xputc('\n');
220 
221   return 0;
222 }
223 
ps_main(void)224 void ps_main(void)
225 {
226   struct strawberry *field;
227   // Octal output code followed by header name
228   char widths[] = {1,1,5,5,5,2,3,3,4,5,6,5,8,8,27,27,11,8,4,5,8,8,8,6},
229        *typos[] = {
230          "F", "S", "UID", "PID", "PPID", "C", "PRI", "NI", "ADDR", "SZ",
231          "WCHAN", "STIME", "TTY", "TIME", "CMD", "COMMAND", "ELAPSED", "GROUP",
232          "%CPU", "PGID", "RGROUP", "RUSER", "USER", "VSZ"
233        };
234   int i, fd = -1;
235 
236   TT.width = 80;
237   terminal_size(&TT.width, 0);
238   TT.width--;
239 
240   // find controlling tty, falling back to /dev/tty if none
241   for (i = fd = 0; i < 4; i++) {
242     struct stat st;
243 
244     if (i != 3 || -1 != (i = fd = open("/dev/tty", O_RDONLY))) {
245       if (isatty(i) && !fstat(i, &st)) {
246         TT.tty = st.st_rdev;
247         break;
248       }
249     }
250   }
251   if (fd != -1) close(fd);
252 
253   sysinfo((void *)toybuf);
254   // Because "TT.uptime = *(long *)toybuf;" triggers a bug in gcc.
255   {
256     long *sigh = (long *)toybuf;
257     TT.uptime = *sigh;
258   }
259 
260   // Manual field selection via -o
261   if (toys.optflags&FLAG_o) {
262     struct arg_list *ol;
263     int length;
264 
265     for (ol = TT.o; ol; ol = ol->next) {
266       char *width, *type, *title, *end, *arg = ol->arg;
267 
268       // Set title, length of title, type, end of type, and display width
269       while ((type = comma_iterate(&arg, &length))) {
270         if ((end = strchr(type, '=')) && length<(end-type)) {
271           title = end+1;
272           length = (end-type)-1;
273         } else {
274           end = type+length;
275           title = 0;
276         }
277 
278         // If changing display width, trim title at the :
279         if ((width = strchr(type, ':')) && width<end) {
280           if (!title) length = width-type;
281         } else width = 0;
282 
283         // Allocate structure, copy title
284         field = xmalloc(sizeof(struct strawberry)+length+1);
285         if (title) {
286           memcpy(field->title, title, length);
287           field->title[length] = 0;
288         }
289         field->len = length;
290 
291         if (width) {
292           field->len = strtol(++width, &title, 10);
293           if (!isdigit(*width) || title != end)
294             error_exit("bad : in -o %s@%ld", ol->arg, title-ol->arg);
295           end = width;
296         }
297 
298         // Find type (reuse width as temp because we're done with it)
299         for (i = 0; i<ARRAY_LEN(typos) && !field->which; i++) {
300           int j, k;
301           char *s;
302 
303           field->which = i;
304           for (j = 0; j < 2; j++) {
305             if (!j) s = typos[i];
306             // posix requires alternate names for some fields
307             else if (-1 == (k = stridx((char []){7, 14, 15, 16}, i))) break;
308             else s = ((char *[]){"nice", "args", "comm", "etime"})[k];
309 
310             if (!strncasecmp(type, s, end-type) && strlen(s)==end-type) break;
311           }
312           if (j!=2) break;
313         }
314         if (i == ARRAY_LEN(typos)) error_exit("bad -o %.*s", end-type, type);
315         if (!field->title) strcpy(field->title, typos[field->which]);
316         dlist_add_nomalloc((void *)&TT.fields, (void *)field);
317       }
318     }
319 
320   // Default fields (also with -f and -l)
321   } else {
322     unsigned short def = 0x7008;
323 
324     if (toys.optflags&FLAG_f) def = 0x783c;
325     if (toys.optflags&FLAG_l) def = 0x77ff;
326 
327     // order of fields[] matches posix STDOUT section, so add enabled XSI
328     // defaults according to bitmask
329 
330     for (i=0; def>>i; i++) {
331       if (!((def>>i)&1)) continue;
332 
333       field = xmalloc(sizeof(struct strawberry)+strlen(typos[i])+1);
334       field->which = i;
335       field->len = widths[i];
336       strcpy(field->title, typos[i]);
337       dlist_add_nomalloc((void *)&TT.fields, (void *)field);
338     }
339   }
340   dlist_terminate(TT.fields);
341 
342   // Print padded headers. (Numbers are right justified, everyting else left.
343   // time and pcpu count as numbers, tty does not)
344   for (field = TT.fields; field; field = field->next) {
345 
346     // right justify F, UID, PID, PPID, PRI, NI, ADDR SZ, TIME, ELAPSED, %CPU
347     // todo: STIME? C?
348     if (!((1<<field->which)&0x523dd)) field->len *= -1;
349     printf(" %*s", field->len, field->title);
350 
351     // -f prints USER but calls it UID (but "ps -o uid -f" is numeric...?)
352     if ((toys.optflags&(FLAG_f|FLAG_o))==FLAG_f && field->which==2)
353       field->which = 22;
354   }
355   xputc('\n');
356 
357   dirtree_read("/proc", do_ps);
358 }
359