ea2022efb
Denys Vlasenko
2025-08-10
Subject
ash: converge waiting code to dash in its form, add comments, no code changes
Binary
No binary (build failed)
Architecture & Compiler Flags
—
Build Log
(log yok)
Commit Diff GitHub →
shell/ash.c+30 -26
| @@ -4412,11 +4412,12 @@ sprint_status48(char *os, int status, int sigonly) | |
| return s - os; | |
| } | |
| - | #define DOWAIT_NONBLOCK 0 |
| - | #define DOWAIT_BLOCK 1 |
| - | #define DOWAIT_BLOCK_OR_SIG 2 |
| + | /* Inside dowait(): */ |
| + | #define DOWAIT_NONBLOCK 0 /* waitpid() will use WNOHANG and won't wait for signals */ |
| + | #define DOWAIT_BLOCK 1 /* waitpid() will NOT use WNOHANG */ |
| + | #define DOWAIT_CHILD_OR_SIG 2 /* waitpid() will use WNOHANG and if got 0, will wait for signals, then loop back */ |
| #if BASH_WAIT_N | |
| - | # define DOWAIT_JOBSTATUS 0x10 /* OR this to get job's exitstatus instead of pid */ |
| + | # define DOWAIT_JOBSTATUS 0x10 /* OR this to get job's exitstatus instead of pid */ |
| #endif | |
| static int | |
| @@ -4437,9 +4438,16 @@ waitproc(int block, int *status) | |
| err = waitpid(-1, status, flags); | |
| while (err < 0 && errno == EINTR); | |
| + | /* Return if error (for example, ECHILD); or if pid found; |
| + | * or if "block" is DOWAIT_NONBLOCK (=0), in this case return -1. |
| + | */ |
| if (err || (err = -!block)) | |
| break; | |
| + | /* "block" is DOWAIT_CHILD_OR_SIG. All children are running |
| + | * (waitpid(WNOHAG) above returned 0), wait for signals: |
| + | */ |
| + | |
| //simpler, but unsafe: a signal can set pending_sig after check, but before pause(): | |
| //while (!gotsigchld && !pending_sig) | |
| // pause(); | |
| @@ -4451,12 +4459,12 @@ waitproc(int block, int *status) | |
| sigclearmask(); | |
| } while (gotsigchld); | |
| + | /* If we fall off the loop, err is 0, which means we got a !SIGCHLD signal */ |
| return err; | |
| } | |
| - | static int |
| - | waitone(int block, struct job *job) |
| + | static int waitone(int block, struct job *job) |
| { | |
| int pid; | |
| int status; | |
| @@ -4495,32 +4503,30 @@ waitone(int block, struct job *job) | |
| for (jp = curjob; jp; jp = jp->prev_job) { | |
| int jobstate; | |
| - | struct procstat *ps; |
| - | struct procstat *psend; |
| + | struct procstat *sp; |
| + | struct procstat *spend; |
| if (jp->state == JOBDONE) | |
| continue; | |
| jobstate = JOBDONE; | |
| - | ps = jp->ps; |
| - | psend = ps + jp->nprocs; |
| + | spend = jp->ps + jp->nprocs; |
| + | sp = jp->ps; |
| do { | |
| - | if (ps->ps_pid == pid) { |
| - | TRACE(("Job %d: changing status of proc %d " |
| - | "from 0x%x to 0x%x\n", |
| - | jobno(jp), pid, ps->ps_status, status)); |
| - | ps->ps_status = status; |
| + | if (sp->ps_pid == pid) { |
| + | TRACE(("Job %d: changing status of proc %d from 0x%x to 0x%x\n", jobno(jp), pid, sp->ps_status, status)); |
| + | sp->ps_status = status; |
| thisjob = jp; | |
| } | |
| - | if (ps->ps_status == -1) |
| + | if (sp->ps_status == -1) |
| jobstate = JOBRUNNING; | |
| #if JOBS | |
| if (jobstate == JOBRUNNING) | |
| continue; | |
| - | if (WIFSTOPPED(ps->ps_status)) { |
| - | jp->stopstatus = ps->ps_status; |
| + | if (WIFSTOPPED(sp->ps_status)) { |
| + | jp->stopstatus = sp->ps_status; |
| jobstate = JOBSTOPPED; | |
| } | |
| #endif | |
| - | } while (++ps < psend); |
| + | } while (++sp < spend); |
| if (!thisjob) | |
| continue; | |
| @@ -4532,8 +4538,7 @@ waitone(int block, struct job *job) | |
| */ | |
| thisjob->changed = 1; | |
| if (thisjob->state != jobstate) { | |
| - | TRACE(("Job %d: changing state from %d to %d\n", |
| - | jobno(thisjob), thisjob->state, jobstate)); |
| + | TRACE(("Job %d: changing state from %d to %d\n", jobno(thisjob), thisjob->state, jobstate)); |
| thisjob->state = jobstate; | |
| #if JOBS | |
| if (jobstate == JOBSTOPPED) | |
| @@ -4568,8 +4573,7 @@ waitone(int block, struct job *job) | |
| return pid; | |
| } | |
| - | static int |
| - | dowait(int block, struct job *jp) |
| + | static int dowait(int block, struct job *jp) |
| { | |
| smallint gotchld = *(volatile smallint *)&gotsigchld; | |
| int rpid; | |
| @@ -4795,9 +4799,9 @@ waitcmd(int argc UNUSED_PARAM, char **argv) | |
| * the trap is executed." | |
| */ | |
| #if BASH_WAIT_N | |
| - | status = dowait(DOWAIT_BLOCK_OR_SIG | DOWAIT_JOBSTATUS, NULL); |
| + | status = dowait(DOWAIT_CHILD_OR_SIG | DOWAIT_JOBSTATUS, NULL); |
| #else | |
| - | dowait(DOWAIT_BLOCK_OR_SIG, NULL); |
| + | dowait(DOWAIT_CHILD_OR_SIG, NULL); |
| #endif | |
| /* if child sends us a signal *and immediately exits*, | |
| * dowait() returns pid > 0. Check this case, | |
| @@ -4838,7 +4842,7 @@ waitcmd(int argc UNUSED_PARAM, char **argv) | |
| job = getjob(*argv, 0); | |
| } | |
| /* loop until process terminated or stopped */ | |
| - | dowait(DOWAIT_BLOCK_OR_SIG, job); |
| + | dowait(DOWAIT_CHILD_OR_SIG, job); |
| if (pending_sig) | |
| goto sigout; | |
| job->waited = 1; | |