external/bsd/tmux/dist/job.c

   1 /* Id */
   2
   3 /*
   4  * Copyright (c) 2009 Nicholas Marriott <nicm@users.sourceforge.net>
   5  *
   6  * Permission to use, copy, modify, and distribute this software for any
   7  * purpose with or without fee is hereby granted, provided that the above
   8  * copyright notice and this permission notice appear in all copies.
   9  *
  10  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
  11  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  12  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
  13  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  14  * WHATSOEVER RESULTING FROM LOSS OF MIND, USE, DATA OR PROFITS, WHETHER
  15  * IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING
  16  * OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  17  */
  18
  19 #include <sys/types.h>
  20 #include <sys/socket.h>
  21
  22 #include <fcntl.h>
  23 #include <stdlib.h>
  24 #include <string.h>
  25 #include <unistd.h>
  26
  27 #include "tmux.h"
  28
  29 /*
  30  * Job scheduling. Run queued commands in the background and record their
  31  * output.
  32  */
  33
  34 void    job_callback(struct bufferevent *, short, void *);
  35 void    job_write_callback(struct bufferevent *, void *);
  36
  37 /* All jobs list. */
  38 struct joblist  all_jobs = LIST_HEAD_INITIALIZER(all_jobs);
  39
  40 /* Start a job running, if it isn't already. */
  41 struct job *
  42 job_run(const char *cmd, struct session *s,
  43     void (*callbackfn)(struct job *), void (*freefn)(void *), void *data)
  44 {
  45         struct job      *job;
  46         struct environ   env;
  47         pid_t            pid;
  48         int              nullfd, out[2];
  49
  50         if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, out) != 0)
  51                 return (NULL);
  52
  53         environ_init(&env);
  54         environ_copy(&global_environ, &env);
  55         if (s != NULL)
  56                 environ_copy(&s->environ, &env);
  57         server_fill_environ(s, &env);
  58
  59         switch (pid = fork()) {
  60         case -1:
  61                 environ_free(&env);
  62                 return (NULL);
  63         case 0:         /* child */
  64                 clear_signals(1);
  65
  66                 environ_push(&env);
  67                 environ_free(&env);
  68
  69                 if (dup2(out[1], STDIN_FILENO) == -1)
  70                         fatal("dup2 failed");
  71                 if (dup2(out[1], STDOUT_FILENO) == -1)
  72                         fatal("dup2 failed");
  73                 if (out[1] != STDIN_FILENO && out[1] != STDOUT_FILENO)
  74                         close(out[1]);
  75                 close(out[0]);
  76
  77                 nullfd = open(_PATH_DEVNULL, O_RDWR, 0);
  78                 if (nullfd < 0)
  79                         fatal("open failed");
  80                 if (dup2(nullfd, STDERR_FILENO) == -1)
  81                         fatal("dup2 failed");
  82                 if (nullfd != STDERR_FILENO)
  83                         close(nullfd);
  84
  85                 closefrom(STDERR_FILENO + 1);
  86
  87                 execl(_PATH_BSHELL, "sh", "-c", cmd, (char *) NULL);
  88                 fatal("execl failed");
  89         }
  90
  91         /* parent */
  92         environ_free(&env);
  93         close(out[1]);
  94
  95         job = xmalloc(sizeof *job);
  96         job->cmd = xstrdup(cmd);
  97         job->pid = pid;
  98         job->status = 0;
  99
 100         LIST_INSERT_HEAD(&all_jobs, job, lentry);
 101
 102         job->callbackfn = callbackfn;
 103         job->freefn = freefn;
 104         job->data = data;
 105
 106         job->fd = out[0];
 107         setblocking(job->fd, 0);
 108
 109         job->event = bufferevent_new(job->fd, NULL, job_write_callback,
 110             job_callback, job);
 111         bufferevent_enable(job->event, EV_READ|EV_WRITE);
 112
 113         log_debug("run job %p: %s, pid %ld", job, job->cmd, (long) job->pid);
 114         return (job);
 115 }
 116
 117 /* Kill and free an individual job. */
 118 void
 119 job_free(struct job *job)
 120 {
 121         log_debug("free job %p: %s", job, job->cmd);
 122
 123         LIST_REMOVE(job, lentry);
 124         free(job->cmd);
 125
 126         if (job->freefn != NULL && job->data != NULL)
 127                 job->freefn(job->data);
 128
 129         if (job->pid != -1)
 130                 kill(job->pid, SIGTERM);
 131         if (job->event != NULL)
 132                 bufferevent_free(job->event);
 133         if (job->fd != -1)
 134                 close(job->fd);
 135
 136         free(job);
 137 }
 138
 139 /* Called when output buffer falls below low watermark (default is 0). */
 140 void
 141 job_write_callback(unused struct bufferevent *bufev, void *data)
 142 {
 143         struct job      *job = data;
 144         size_t           len = EVBUFFER_LENGTH(EVBUFFER_OUTPUT(job->event));
 145
 146         log_debug("job write %p: %s, pid %ld, output left %zu", job, job->cmd,
 147             (long) job->pid, len);
 148
 149         if (len == 0) {
 150                 shutdown(job->fd, SHUT_WR);
 151                 bufferevent_disable(job->event, EV_WRITE);
 152         }
 153 }
 154
 155 /* Job buffer error callback. */
 156 void
 157 job_callback(unused struct bufferevent *bufev, unused short events, void *data)
 158 {
 159         struct job      *job = data;
 160
 161         log_debug("job error %p: %s, pid %ld", job, job->cmd, (long) job->pid);
 162
 163         if (job->pid == -1) {
 164                 if (job->callbackfn != NULL)
 165                         job->callbackfn(job);
 166                 job_free(job);
 167         } else {
 168                 bufferevent_disable(job->event, EV_READ);
 169                 close(job->fd);
 170                 job->fd = -1;
 171         }
 172 }
 173
 174 /* Job died (waitpid() returned its pid). */
 175 void
 176 job_died(struct job *job, int status)
 177 {
 178         log_debug("job died %p: %s, pid %ld", job, job->cmd, (long) job->pid);
 179
 180         job->status = status;
 181
 182         if (job->fd == -1) {
 183                 if (job->callbackfn != NULL)
 184                         job->callbackfn(job);
 185                 job_free(job);
 186         } else
 187                 job->pid = -1;
 188 }