job.c

   1 /* $OpenBSD$ */
   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 <paths.h>
  24 #include <stdlib.h>
  25 #include <string.h>
  26 #include <unistd.h>
  27
  28 #include "tmux.h"
  29
  30 /*
  31  * Job scheduling. Run queued commands in the background and record their
  32  * output.
  33  */
  34
  35 void    job_callback(struct bufferevent *, short, void *);
  36 void    job_write_callback(struct bufferevent *, void *);
  37
  38 /* All jobs list. */
  39 struct joblist  all_jobs = LIST_HEAD_INITIALIZER(all_jobs);
  40
  41 /* Start a job running, if it isn't already. */
  42 struct job *
  43 job_run(const char *cmd, struct session *s,
  44     void (*callbackfn)(struct job *), void (*freefn)(void *), void *data)
  45 {
  46         struct job      *job;
  47         struct environ   env;
  48         pid_t            pid;
  49         int              nullfd, out[2];
  50
  51         if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, out) != 0)
  52                 return (NULL);
  53
  54         environ_init(&env);
  55         environ_copy(&global_environ, &env);
  56         if (s != NULL)
  57                 environ_copy(&s->environ, &env);
  58         server_fill_environ(s, &env);
  59
  60         switch (pid = fork()) {
  61         case -1:
  62                 environ_free(&env);
  63                 return (NULL);
  64         case 0:         /* child */
  65                 clear_signals(1);
  66
  67                 environ_push(&env);
  68                 environ_free(&env);
  69
  70                 if (dup2(out[1], STDIN_FILENO) == -1)
  71                         fatal("dup2 failed");
  72                 if (dup2(out[1], STDOUT_FILENO) == -1)
  73                         fatal("dup2 failed");
  74                 if (out[1] != STDIN_FILENO && out[1] != STDOUT_FILENO)
  75                         close(out[1]);
  76                 close(out[0]);
  77
  78                 nullfd = open(_PATH_DEVNULL, O_RDWR, 0);
  79                 if (nullfd < 0)
  80                         fatal("open failed");
  81                 if (dup2(nullfd, STDERR_FILENO) == -1)
  82                         fatal("dup2 failed");
  83                 if (nullfd != STDERR_FILENO)
  84                         close(nullfd);
  85
  86                 closefrom(STDERR_FILENO + 1);
  87
  88                 execl(_PATH_BSHELL, "sh", "-c", cmd, (char *) NULL);
  89                 fatal("execl failed");
  90         }
  91
  92         /* parent */
  93         environ_free(&env);
  94         close(out[1]);
  95
  96         job = xmalloc(sizeof *job);
  97         job->cmd = xstrdup(cmd);
  98         job->pid = pid;
  99         job->status = 0;
 100
 101         LIST_INSERT_HEAD(&all_jobs, job, lentry);
 102
 103         job->callbackfn = callbackfn;
 104         job->freefn = freefn;
 105         job->data = data;
 106
 107         job->fd = out[0];
 108         setblocking(job->fd, 0);
 109
 110         job->event = bufferevent_new(job->fd, NULL, job_write_callback,
 111             job_callback, job);
 112         bufferevent_enable(job->event, EV_READ|EV_WRITE);
 113
 114         log_debug("run job %p: %s, pid %ld", job, job->cmd, (long) job->pid);
 115         return (job);
 116 }
 117
 118 /* Kill and free an individual job. */
 119 void
 120 job_free(struct job *job)
 121 {
 122         log_debug("free job %p: %s", job, job->cmd);
 123
 124         LIST_REMOVE(job, lentry);
 125         free(job->cmd);
 126
 127         if (job->freefn != NULL && job->data != NULL)
 128                 job->freefn(job->data);
 129
 130         if (job->pid != -1)
 131                 kill(job->pid, SIGTERM);
 132         if (job->event != NULL)
 133                 bufferevent_free(job->event);
 134         if (job->fd != -1)
 135                 close(job->fd);
 136
 137         free(job);
 138 }
 139
 140 /* Called when output buffer falls below low watermark (default is 0). */
 141 void
 142 job_write_callback(unused struct bufferevent *bufev, void *data)
 143 {
 144         struct job      *job = data;
 145         size_t           len = EVBUFFER_LENGTH(EVBUFFER_OUTPUT(job->event));
 146
 147         log_debug("job write %p: %s, pid %ld, output left %zu", job, job->cmd,
 148             (long) job->pid, len);
 149
 150         if (len == 0) {
 151                 shutdown(job->fd, SHUT_WR);
 152                 bufferevent_disable(job->event, EV_WRITE);
 153         }
 154 }
 155
 156 /* Job buffer error callback. */
 157 void
 158 job_callback(unused struct bufferevent *bufev, unused short events, void *data)
 159 {
 160         struct job      *job = data;
 161
 162         log_debug("job error %p: %s, pid %ld", job, job->cmd, (long) job->pid);
 163
 164         if (job->pid == -1) {
 165                 if (job->callbackfn != NULL)
 166                         job->callbackfn(job);
 167                 job_free(job);
 168         } else {
 169                 bufferevent_disable(job->event, EV_READ);
 170                 close(job->fd);
 171                 job->fd = -1;
 172         }
 173 }
 174
 175 /* Job died (waitpid() returned its pid). */
 176 void
 177 job_died(struct job *job, int status)
 178 {
 179         log_debug("job died %p: %s, pid %ld", job, job->cmd, (long) job->pid);
 180
 181         job->status = status;
 182
 183         if (job->fd == -1) {
 184                 if (job->callbackfn != NULL)
 185                         job->callbackfn(job);
 186                 job_free(job);
 187         } else
 188                 job->pid = -1;
 189 }