1 /* Linux-specific PROCFS manipulation routines.
2    Copyright (C) 2009-2013 Free Software Foundation, Inc.
3 
4    This file is part of GDB.
5 
6    This program is free software; you can redistribute it and/or modify
7    it under the terms of the GNU General Public License as published by
8    the Free Software Foundation; either version 3 of the License, or
9    (at your option) any later version.
10 
11    This program is distributed in the hope that it will be useful,
12    but WITHOUT ANY WARRANTY; without even the implied warranty of
13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14    GNU General Public License for more details.
15 
16    You should have received a copy of the GNU General Public License
17    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
18 
19 #ifdef GDBSERVER
20 #include "server.h"
21 #else
22 #include "defs.h"
23 #include "gdb_string.h"
24 #endif
25 
26 #include "linux-procfs.h"
27 
28 /* Return the TGID of LWPID from /proc/pid/status.  Returns -1 if not
29    found.  */
30 
31 static int
32 linux_proc_get_int (pid_t lwpid, const char *field)
33 {
34   size_t field_len = strlen (field);
35   FILE *status_file;
36   char buf[100];
37   int retval = -1;
38 
39   snprintf (buf, sizeof (buf), "/proc/%d/status", (int) lwpid);
40   status_file = fopen (buf, "r");
41   if (status_file == NULL)
42     {
43       warning (_("unable to open /proc file '%s'"), buf);
44       return -1;
45     }
46 
47   while (fgets (buf, sizeof (buf), status_file))
48     if (strncmp (buf, field, field_len) == 0 && buf[field_len] == ':')
49       {
50 	retval = strtol (&buf[field_len + 1], NULL, 10);
51 	break;
52       }
53 
54   fclose (status_file);
55   return retval;
56 }
57 
58 /* Return the TGID of LWPID from /proc/pid/status.  Returns -1 if not
59    found.  */
60 
61 int
62 linux_proc_get_tgid (pid_t lwpid)
63 {
64   return linux_proc_get_int (lwpid, "Tgid");
65 }
66 
67 /* See linux-procfs.h.  */
68 
69 pid_t
70 linux_proc_get_tracerpid (pid_t lwpid)
71 {
72   return linux_proc_get_int (lwpid, "TracerPid");
73 }
74 
75 /* Return non-zero if 'State' of /proc/PID/status contains STATE.  */
76 
77 static int
78 linux_proc_pid_has_state (pid_t pid, const char *state)
79 {
80   char buffer[100];
81   FILE *procfile;
82   int retval;
83   int have_state;
84 
85   xsnprintf (buffer, sizeof (buffer), "/proc/%d/status", (int) pid);
86   procfile = fopen (buffer, "r");
87   if (procfile == NULL)
88     {
89       warning (_("unable to open /proc file '%s'"), buffer);
90       return 0;
91     }
92 
93   have_state = 0;
94   while (fgets (buffer, sizeof (buffer), procfile) != NULL)
95     if (strncmp (buffer, "State:", 6) == 0)
96       {
97 	have_state = 1;
98 	break;
99       }
100   retval = (have_state && strstr (buffer, state) != NULL);
101   fclose (procfile);
102   return retval;
103 }
104 
105 /* Detect `T (stopped)' in `/proc/PID/status'.
106    Other states including `T (tracing stop)' are reported as false.  */
107 
108 int
109 linux_proc_pid_is_stopped (pid_t pid)
110 {
111   return linux_proc_pid_has_state (pid, "T (stopped)");
112 }
113 
114 /* See linux-procfs.h declaration.  */
115 
116 int
117 linux_proc_pid_is_zombie (pid_t pid)
118 {
119   return linux_proc_pid_has_state (pid, "Z (zombie)");
120 }
121