diff options
Diffstat (limited to 'Src/jobs.c')
| -rw-r--r-- | Src/jobs.c | 138 |
1 files changed, 117 insertions, 21 deletions
diff --git a/Src/jobs.c b/Src/jobs.c index bd95afb7a..18bb648d9 100644 --- a/Src/jobs.c +++ b/Src/jobs.c @@ -104,15 +104,6 @@ int prev_errflag, prev_breaks, errbrk_saved; /**/ int numpipestats, pipestats[MAX_PIPESTATS]; -/* - * The status associated with the process lastpid. - * -1 if not set and no associated lastpid - * -2 if lastpid is set and status isn't yet - * else the value returned by wait(). - */ -/**/ -long lastpid_status; - /* Diff two timevals for elapsed-time computations */ /**/ @@ -1309,14 +1300,6 @@ addproc(pid_t pid, char *text, int aux, struct timeval *bgtime) { Process pn, *pnlist; - if (pid == lastpid && lastpid_status != -2L) { - /* - * The status for the previous lastpid is invalid. - * Presumably process numbers have wrapped. - */ - lastpid_status = -1L; - } - DPUTS(thisjob == -1, "No valid job in addproc."); pn = (Process) zshcalloc(sizeof *pn); pn->pid = pid; @@ -1940,6 +1923,122 @@ maybeshrinkjobtab(void) unqueue_signals(); } +/* + * Definitions for the background process stuff recorded below. + * This would be more efficient as a hash, but + * - that's quite heavyweight for something not needed very often + * - we need some kind of ordering as POSIX allows us to limit + * the size of the list to the value of _SC_CHILD_MAX and clearly + * we want to clear the oldest first + * - cases with a long list of background jobs where the user doesn't + * wait for a large number, and then does wait for one (the only + * inefficient case) are rare + * - in the context of waiting for an external process, looping + * over a list isn't so very inefficient. + * Enough excuses already. + */ + +/* Data in the link list, a key (process ID) / value (exit status) pair. */ +struct bgstatus { + pid_t pid; + int status; +}; +typedef struct bgstatus *Bgstatus; +/* The list of those entries */ +LinkList bgstatus_list; +/* Count of entries. Reaches value of _SC_CHILD_MAX and stops. */ +long bgstatus_count; + +/* + * Remove and free a bgstatus entry. + */ +static void rembgstatus(LinkNode node) +{ + zfree(remnode(bgstatus_list, node), sizeof(struct bgstatus)); + bgstatus_count--; +} + +/* + * Record the status of a background process that exited so we + * can execute the builtin wait for it. + * + * We can't execute the wait builtin for something that exited in the + * foreground as it's not visible to the user, so don't bother recording. + */ + +/**/ +void +addbgstatus(pid_t pid, int status) +{ + static long child_max; + Bgstatus bgstatus_entry; + + if (!child_max) { +#ifdef _SC_CHILD_MAX + child_max = sysconf(_SC_CHILD_MAX); + if (!child_max) /* paranoia */ +#endif + { + /* Be inventive */ + child_max = 1024L; + } + } + + if (!bgstatus_list) { + bgstatus_list = znewlinklist(); + /* + * We're not always robust about memory failures, but + * this is pretty deep in the shell basics to be failing owing + * to memory, and a failure to wait is reported loudly, so test + * and fail silently here. + */ + if (!bgstatus_list) + return; + } + if (bgstatus_count == child_max) { + /* Overflow. List is in order, remove first */ + rembgstatus(firstnode(bgstatus_list)); + } + bgstatus_entry = (Bgstatus)zalloc(sizeof(*bgstatus_entry)); + if (!bgstatus_entry) { + /* See note above */ + return; + } + bgstatus_entry->pid = pid; + bgstatus_entry->status = status; + if (!zaddlinknode(bgstatus_list, bgstatus_entry)) { + zfree(bgstatus_entry, sizeof(*bgstatus_entry)); + return; + } + bgstatus_count++; +} + +/* + * See if pid has a recorded exit status. + * Note we make no guarantee that the PIDs haven't wrapped, so this + * may not be the right process. + * + * This is only used by wait, which must only work on each + * pid once, so we need to remove the entry if we find it. + */ + +static int getbgstatus(pid_t pid) +{ + LinkNode node; + Bgstatus bgstatus_entry; + + if (!bgstatus_list) + return -1; + for (node = firstnode(bgstatus_list); node; incnode(node)) { + bgstatus_entry = (Bgstatus)getdata(node); + if (bgstatus_entry->pid == pid) { + int status = bgstatus_entry->status; + rembgstatus(node); + return status; + } + } + return -1; +} /* bg, disown, fg, jobs, wait: most of the job control commands are * * here. They all take the same type of argument. Exception: wait can * @@ -2085,10 +2184,7 @@ bin_fg(char *name, char **argv, Options ops, int func) } if (retval == 0) retval = lastval2; - } else if (isset(POSIXJOBS) && - pid == lastpid && lastpid_status >= 0L) { - retval = (int)lastpid_status; - } else { + } else if ((retval = getbgstatus(pid)) < 0) { zwarnnam(name, "pid %d is not a child of this shell", pid); /* presumably lastval2 doesn't tell us a heck of a lot? */ retval = 1; |