execute.c

   1 /*-*- Mode: C; c-basic-offset: 8 -*-*/
   2
   3 #include <assert.h>
   4 #include <dirent.h>
   5 #include <errno.h>
   6 #include <fcntl.h>
   7 #include <unistd.h>
   8 #include <string.h>
   9
  10 #include "execute.h"
  11 #include "strv.h"
  12 #include "macro.h"
  13 #include "util.h"
  14 #include "log.h"
  15
  16 static int close_fds(int except[], unsigned n_except) {
  17         DIR *d;
  18         struct dirent *de;
  19         int r = 0;
  20
  21         /* Modifies the fds array! (sorts it) */
  22
  23         if (!(d = opendir("/proc/self/fd")))
  24                 return -errno;
  25
  26         while ((de = readdir(d))) {
  27                 int fd;
  28
  29                 if (de->d_name[0] == '.')
  30                         continue;
  31
  32                 if ((r = safe_atoi(de->d_name, &fd)) < 0)
  33                         goto finish;
  34
  35                 if (fd < 3)
  36                         continue;
  37
  38                 if (fd == dirfd(d))
  39                         continue;
  40
  41                 if (except) {
  42                         bool found;
  43                         unsigned i;
  44
  45                         found = false;
  46                         for (i = 0; i < n_except; i++)
  47                                 if (except[i] == fd) {
  48                                         found = true;
  49                                         break;
  50                                 }
  51
  52                         if (found)
  53                                 continue;
  54                 }
  55
  56                 if ((r = close_nointr(fd)) < 0)
  57                         goto finish;
  58         }
  59
  60 finish:
  61         closedir(d);
  62         return r;
  63 }
  64
  65 static int shift_fds(int fds[], unsigned n_fds) {
  66         int start, restart_from;
  67
  68         if (n_fds <= 0)
  69                 return 0;
  70
  71         assert(fds);
  72
  73         start = 0;
  74         for (;;) {
  75                 int i;
  76
  77                 restart_from = -1;
  78
  79                 for (i = start; i < (int) n_fds; i++) {
  80                         int nfd;
  81
  82                         /* Already at right index? */
  83                         if (fds[i] == i+3)
  84                                 continue;
  85
  86                         if ((nfd = fcntl(fds[i], F_DUPFD, i+3)) < 0)
  87                                 return -errno;
  88
  89                         assert_se(close_nointr(fds[i]) == 0);
  90                         fds[i] = nfd;
  91
  92                         /* Hmm, the fd we wanted isn't free? Then
  93                          * let's remember that and try again from here*/
  94                         if (nfd != i+3 && restart_from < 0)
  95                                 restart_from = i;
  96                 }
  97
  98                 if (restart_from < 0)
  99                         break;
 100
 101                 start = restart_from;
 102         }
 103
 104         return 0;
 105 }
 106
 107 int exec_spawn(const ExecCommand *command, const ExecContext *context, int *fds, unsigned n_fds, pid_t *ret) {
 108         pid_t pid;
 109
 110         assert(command);
 111         assert(context);
 112         assert(ret);
 113         assert(fds || n_fds <= 0);
 114
 115         log_debug("about to execute %s", command->path);
 116
 117         if ((pid = fork()) < 0)
 118                 return -errno;
 119
 120         if (pid == 0) {
 121                 char **e, **f = NULL;
 122                 int i, r;
 123                 char t[16];
 124                 /* child */
 125
 126                 umask(context->umask);
 127
 128                 if (chdir(context->directory ? context->directory : "/") < 0) {
 129                         r = EXIT_CHDIR;
 130                         goto fail;
 131                 }
 132
 133                 snprintf(t, sizeof(t), "%i", context->oom_adjust);
 134                 char_array_0(t);
 135
 136                 if (write_one_line_file("/proc/self/oom_adj", t) < 0) {
 137                         r = EXIT_OOM_ADJUST;
 138                         goto fail;
 139                 }
 140
 141                 if (setpriority(PRIO_PROCESS, 0, context->nice) < 0) {
 142                         r = EXIT_NICE;
 143                         goto fail;
 144                 }
 145
 146                 if (close_fds(fds, n_fds) < 0 ||
 147                     shift_fds(fds, n_fds) < 0) {
 148                         r = EXIT_FDS;
 149                         goto fail;
 150                 }
 151
 152                 for (i = 0; i < RLIMIT_NLIMITS; i++) {
 153                         if (!context->rlimit[i])
 154                                 continue;
 155
 156                         if (setrlimit(i, context->rlimit[i]) < 0) {
 157                                 r = EXIT_LIMITS;
 158                                 goto fail;
 159                         }
 160                 }
 161
 162                 if (n_fds > 0) {
 163                         char a[64], b[64];
 164                         char *listen_env[3] = {
 165                                 a,
 166                                 b,
 167                                 NULL
 168                         };
 169
 170                         snprintf(a, sizeof(a), "LISTEN_PID=%llu", (unsigned long long) getpid());
 171                         snprintf(b, sizeof(b), "LISTEN_FDS=%u", n_fds);
 172
 173                         a[sizeof(a)-1] = 0;
 174                         b[sizeof(b)-1] = 0;
 175
 176                         if (context->environment) {
 177                                 if (!(f = strv_merge(listen_env, context->environment))) {
 178                                         r = EXIT_MEMORY;
 179                                         goto fail;
 180                                 }
 181                                 e = f;
 182                         } else
 183                                 e = listen_env;
 184
 185                 } else
 186                         e = context->environment;
 187
 188                 execve(command->path, command->argv, e);
 189                 r = EXIT_EXEC;
 190
 191         fail:
 192                 strv_free(f);
 193                 _exit(r);
 194         }
 195
 196
 197         log_debug("executed %s as %llu", command->path, (unsigned long long) pid);
 198
 199         *ret = pid;
 200         return 0;
 201 }
 202
 203 void exec_context_init(ExecContext *c) {
 204         assert(c);
 205
 206         c->umask = 0002;
 207         cap_clear(c->capabilities);
 208         c->oom_adjust = 0;
 209         c->nice = 0;
 210 }
 211
 212 void exec_context_done(ExecContext *c) {
 213         unsigned l;
 214
 215         assert(c);
 216
 217         strv_free(c->environment);
 218         c->environment = NULL;
 219
 220         for (l = 0; l < ELEMENTSOF(c->rlimit); l++) {
 221                 free(c->rlimit[l]);
 222                 c->rlimit[l] = NULL;
 223         }
 224
 225         free(c->directory);
 226         c->directory = NULL;
 227
 228         free(c->user);
 229         c->user = NULL;
 230
 231         free(c->group);
 232         c->group = NULL;
 233
 234         strv_free(c->supplementary_groups);
 235         c->supplementary_groups = NULL;
 236 }
 237
 238 void exec_command_free_list(ExecCommand *c) {
 239         ExecCommand *i;
 240
 241         while ((i = c)) {
 242                 LIST_REMOVE(ExecCommand, command, c, i);
 243
 244                 free(i->path);
 245                 strv_free(i->argv);
 246                 free(i);
 247         }
 248 }
 249
 250 void exec_command_free_array(ExecCommand **c, unsigned n) {
 251         unsigned i;
 252
 253         for (i = 0; i < n; i++) {
 254                 exec_command_free_list(c[i]);
 255                 c[i] = NULL;
 256         }
 257 }
 258
 259 void exec_context_dump(ExecContext *c, FILE* f, const char *prefix) {
 260         assert(c);
 261         assert(f);
 262
 263         if (!prefix)
 264                 prefix = "";
 265
 266         fprintf(f,
 267                 "%sUmask: %04o\n"
 268                 "%sDirectory: %s\n"
 269                 "%sNice: %i\n"
 270                 "%sOOMAdjust: %i\n",
 271                 prefix, c->umask,
 272                 prefix, c->directory ? c->directory : "/",
 273                 prefix, c->nice,
 274                 prefix, c->oom_adjust);
 275 }
 276
 277 void exec_status_fill(ExecStatus *s, pid_t pid, int code, int status) {
 278         assert(s);
 279
 280         s->pid = pid;
 281         s->code = code;
 282         s->status = status;
 283         s->timestamp = now(CLOCK_REALTIME);
 284 }
 285
 286 char *exec_command_line(ExecCommand *c) {
 287         size_t k;
 288         char *n, *p, **a;
 289         bool first = true;
 290
 291         assert(c);
 292         assert(c->argv);
 293
 294         k = 1;
 295         STRV_FOREACH(a, c->argv)
 296                 k += strlen(*a)+3;
 297
 298         if (!(n = new(char, k)))
 299                 return NULL;
 300
 301         p = n;
 302         STRV_FOREACH(a, c->argv) {
 303
 304                 if (!first)
 305                         *(p++) = ' ';
 306                 else
 307                         first = false;
 308
 309                 if (strpbrk(*a, WHITESPACE)) {
 310                         *(p++) = '\'';
 311                         p = stpcpy(p, *a);
 312                         *(p++) = '\'';
 313                 } else
 314                         p = stpcpy(p, *a);
 315
 316         }
 317
 318         *p = 0;
 319
 320         /* FIXME: this doesn't really handle arguments that have
 321          * spaces and ticks in them */
 322
 323         return n;
 324 }
 325
 326 void exec_command_dump(ExecCommand *c, FILE *f, const char *prefix) {
 327         char *cmd;
 328
 329         assert(c);
 330         assert(f);
 331
 332         if (!prefix)
 333                 prefix = "";
 334
 335         cmd = exec_command_line(c);
 336
 337         fprintf(f,
 338                 "%sCommand Line: %s\n",
 339                 prefix, cmd ? cmd : strerror(ENOMEM));
 340
 341         free(cmd);
 342 }
 343
 344 void exec_command_dump_list(ExecCommand *c, FILE *f, const char *prefix) {
 345         assert(f);
 346
 347         if (!prefix)
 348                 prefix = "";
 349
 350         LIST_FOREACH(command, c, c)
 351                 exec_command_dump(c, f, prefix);
 352 }