git.itanic.dy.fi Git - scan-pagemap/blob - pidlib.c

   1 #include <sys/types.h>
   2 #include <sys/stat.h>
   3 #include <unistd.h>
   4 #include <stdlib.h>
   5 #include <stdio.h>
   6 #include <libgen.h>
   7 #include <errno.h>
   8 #include <string.h>
   9
  10 #include "pidlib.h"
  11
  12 char *get_name_by_pid(int pid)
  13 {
  14         static int last_pid;
  15         static char cmdline[128];
  16         static char *bname;
  17
  18         if (last_pid == pid)
  19                 return bname;
  20
  21         if (read_cmdline(pid, pid, cmdline, sizeof(cmdline))) {
  22                 bname = NULL;
  23                 return NULL;
  24         }
  25
  26         bname = basename(cmdline);
  27
  28         last_pid = pid;
  29         return bname;
  30 }
  31
  32 static int parse_pid(DIR **dir)
  33 {
  34         struct dirent *dirent;
  35         int error;
  36
  37 restart:
  38         dirent = readdir(*dir);
  39         if (!dirent) {
  40                 if (errno == 0) {
  41                         closedir(*dir);
  42                         *dir = NULL;
  43                         return 0;
  44                 }
  45                 error = errno;
  46                 printf("Failed to read /proc directory: %s\n", strerror(error));
  47                 return -1;
  48         }
  49
  50         if (dirent->d_name[0] < '0' || dirent->d_name[0] > '9')
  51                 goto restart;
  52
  53         return atoi(dirent->d_name);
  54 }
  55
  56 static int opendir_check(DIR **dir, const char *path)
  57 {
  58         int error;
  59
  60         if (!*dir) {
  61                 *dir = opendir(path);
  62                 if (!dir) {
  63                         error = errno;
  64                         fprintf(stderr, "Failed to open %s directory: %s\n",
  65                                 path, strerror(error));
  66                         return -1;
  67                 }
  68         }
  69
  70         return 0;
  71 }
  72
  73 int get_next_tid(int pid, DIR **dir)
  74 {
  75         if (*dir == NULL) {
  76                 char path[64];
  77
  78                 snprintf(path, sizeof(path), "/proc/%d/task/", pid);
  79                 if (opendir_check(dir, path))
  80                         return -1;
  81         }
  82
  83         return parse_pid(dir);
  84 }
  85
  86 int get_next_pid(DIR **dir)
  87 {
  88         if (opendir_check(dir, "/proc"))
  89                 return -1;
  90
  91         return parse_pid(dir);
  92 }
  93
  94 int get_next_pid_by_name(DIR **dir, char *name)
  95 {
  96         int pid;
  97         char *pname;
  98
  99         if (opendir_check(dir, "/proc"))
 100                 return -1;
 101
 102         while (1) {
 103                 pid = parse_pid(dir);
 104                 if (pid <= 0)
 105                         break;
 106
 107                 pname = get_name_by_pid(pid);
 108                 if (pname == NULL)
 109                         continue;
 110                 if (strcmp(pname, name))
 111                         continue;
 112
 113                 return pid;
 114         }
 115
 116         return 0;
 117 }
 118
 119 int read_cmdline(int pid, int tid, char *cmdline, size_t len)
 120 {
 121         FILE *file;
 122         char path[512];
 123         int ret;
 124
 125         snprintf(path, sizeof(path), "/proc/%d/task/%d/cmdline", pid, tid);
 126         file = fopen(path, "rb");
 127
 128         if (!file)
 129                 return -1;
 130
 131         ret = fread(cmdline, 1, len, file);
 132         if (ret > 0)
 133                 cmdline[ret - 1] = 0;
 134         fclose(file);
 135
 136         return ret > 0 ? 0 : -1;
 137 }
 138
 139 static int pid_is_ok(int pid)
 140 {
 141         struct stat statt;
 142         char path[64];
 143
 144         snprintf(path, sizeof(path), "/proc/%d/", pid);
 145
 146         if (stat(path, &statt))
 147                 return 0;
 148
 149         return pid;
 150 }
 151
 152 /*
 153  * Test whether a pid string number exists in the system as a pid
 154  * number
 155  */
 156 int pidstr_is_ok(const char *str)
 157 {
 158         int i, pid;
 159
 160         /* Test that it is all digits */
 161         for (i = 0; i < strlen(str); i++)
 162                 if (str[i] < '0' || str[i] > '9')
 163                         return 0;
 164
 165         pid = atoi(str);
 166
 167         return pid_is_ok(pid);
 168 }