diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/sort.c | 159 |
1 files changed, 80 insertions, 79 deletions
diff --git a/src/sort.c b/src/sort.c index f53e64d9c..6bce49b4e 100644 --- a/src/sort.c +++ b/src/sort.c @@ -610,32 +610,33 @@ cs_leave (struct cs_status status) } } +/* Possible states for a temp file. If compressed, the file's status + is unreaped or reaped, depending on whether 'sort' has waited for + the subprocess to finish. */ +enum { UNCOMPRESSED, UNREAPED, REAPED }; + /* The list of temporary files. */ struct tempnode { struct tempnode *volatile next; - pid_t pid; /* If compressed, the pid of compressor, else zero */ + pid_t pid; /* The subprocess PID; undefined if state == UNCOMPRESSED. */ + char state; char name[1]; /* Actual size is 1 + file name length. */ }; static struct tempnode *volatile temphead; static struct tempnode *volatile *temptail = &temphead; +/* A file to be sorted. */ struct sortfile { + /* The file's name. */ char const *name; - pid_t pid; /* If compressed, the pid of compressor, else zero */ -}; -/* An integer that is the same size as a pointer. To avoid GCC warnings, - cast from void * to this type rather than directly to pid_t. */ -#ifdef UINTPTR_MAX -typedef uintptr_t uintptr; -#else -typedef size_t uintptr; -#endif -verify (sizeof (pid_t) <= sizeof (uintptr)); + /* Nonnull if this is a temporary file, in which case NAME == TEMP->name. */ + struct tempnode *temp; +}; -/* IDs of unreaped compression and decompression subprocesses. */ +/* Map PIDs of unreaped subprocesses to their struct tempnode objects. */ static Hash_table *proctab; enum { INIT_PROCTAB_SIZE = 47 }; @@ -643,16 +644,16 @@ enum { INIT_PROCTAB_SIZE = 47 }; static size_t proctab_hasher (void const *entry, size_t tabsize) { - pid_t pid = (uintptr) entry; - return pid % tabsize; + struct tempnode const *node = entry; + return node->pid % tabsize; } static bool proctab_comparator (void const *e1, void const *e2) { - pid_t p1 = (uintptr) e1; - pid_t p2 = (uintptr) e2; - return p1 == p2; + struct tempnode const *n1 = e1; + struct tempnode const *n2 = e2; + return n1->pid == n2->pid; } /* The number of unreaped child processes. */ @@ -690,11 +691,11 @@ reap (pid_t pid) return cpid; } -/* Add PID to the process table. Create the process table the first - time it's called. */ +/* TEMP represents a new process; add it to the process table. Create + the process table the first time it's called. */ static void -register_proc (pid_t pid) +register_proc (struct tempnode *temp) { if (! proctab) { @@ -706,8 +707,9 @@ register_proc (pid_t pid) xalloc_die (); } - uintptr p = pid; - if (! hash_insert (proctab, (void *) p)) + temp->state = UNREAPED; + + if (! hash_insert (proctab, temp)) xalloc_die (); } @@ -717,8 +719,14 @@ register_proc (pid_t pid) static bool delete_proc (pid_t pid) { - uintptr p = pid; - return !! hash_delete (proctab, (void *) p); + struct tempnode test; + + test.pid = pid; + struct tempnode *node = hash_delete (proctab, &test); + if (! node) + return false; + node->state = REAPED; + return true; } /* Remove PID from the process table, and wait for it to exit if it @@ -802,7 +810,6 @@ create_temp_file (int *pfd, bool survive_fd_exhaustion) memcpy (file, temp_dir, len); memcpy (file + len, slashbase, sizeof slashbase); node->next = NULL; - node->pid = 0; if (++temp_dir_index == temp_dir_count) temp_dir_index = 0; @@ -1010,23 +1017,21 @@ pipe_fork (int pipefds[2], size_t tries) #endif } -/* Create a temporary file and start a compression program to filter output - to that file. Set *PFP to the file handle and if PPID is non-NULL, - set *PPID to the PID of the newly-created process. If the creation +/* Create a temporary file and, if asked for, start a compressor + to that file. Set *PFP to the file handle and return + the address of the new temp node. If the creation fails, return NULL if the failure is due to file descriptor exhaustion and SURVIVE_FD_EXHAUSTION; otherwise, die. */ -static char * -maybe_create_temp (FILE **pfp, pid_t *ppid, bool survive_fd_exhaustion) +static struct tempnode * +maybe_create_temp (FILE **pfp, bool survive_fd_exhaustion) { int tempfd; struct tempnode *node = create_temp_file (&tempfd, survive_fd_exhaustion); - char *name; - if (! node) return NULL; - name = node->name; + node->state = UNCOMPRESSED; if (compress_program) { @@ -1039,7 +1044,7 @@ maybe_create_temp (FILE **pfp, pid_t *ppid, bool survive_fd_exhaustion) close (pipefds[0]); tempfd = pipefds[1]; - register_proc (node->pid); + register_proc (node); } else if (node->pid == 0) { @@ -1053,45 +1058,40 @@ maybe_create_temp (FILE **pfp, pid_t *ppid, bool survive_fd_exhaustion) error (SORT_FAILURE, errno, _("couldn't execute %s"), compress_program); } - else - node->pid = 0; } *pfp = fdopen (tempfd, "w"); if (! *pfp) - die (_("couldn't create temporary file"), name); - - if (ppid) - *ppid = node->pid; + die (_("couldn't create temporary file"), node->name); - return name; + return node; } -/* Create a temporary file and start a compression program to filter output - to that file. Set *PFP to the file handle and if *PPID is non-NULL, - set it to the PID of the newly-created process. Die on failure. */ +/* Create a temporary file and, if asked for, start a compressor + to that file. Set *PFP to the file handle and return the address + of the new temp node. Die on failure. */ -static char * -create_temp (FILE **pfp, pid_t *ppid) +static struct tempnode * +create_temp (FILE **pfp) { - return maybe_create_temp (pfp, ppid, false); + return maybe_create_temp (pfp, false); } /* Open a compressed temp file and start a decompression process through - which to filter the input. PID must be the valid processes ID of the - process used to compress the file. Return NULL (setting errno to + which to filter the input. Return NULL (setting errno to EMFILE) if we ran out of file descriptors, and die on any other kind of failure. */ static FILE * -open_temp (char const *name, pid_t pid) +open_temp (struct tempnode *temp) { int tempfd, pipefds[2]; FILE *fp = NULL; - wait_proc (pid); + if (temp->state == UNREAPED) + wait_proc (temp->pid); - tempfd = open (name, O_RDONLY); + tempfd = open (temp->name, O_RDONLY); if (tempfd < 0) return NULL; @@ -1119,7 +1119,8 @@ open_temp (char const *name, pid_t pid) compress_program); default: - register_proc (child); + temp->pid = child; + register_proc (temp); close (tempfd); close (pipefds[1]); @@ -1161,6 +1162,9 @@ zaptemp (char const *name) for (pnode = &temphead; (node = *pnode)->name != name; pnode = &node->next) continue; + if (node->state == UNREAPED) + wait_proc (node->pid); + /* Unlink the temporary file in a critical section to avoid races. */ next = node->next; cs = cs_enter (); @@ -2773,8 +2777,8 @@ open_input_files (struct sortfile *files, size_t nfiles, FILE ***pfps) /* Open as many input files as we can. */ for (i = 0; i < nfiles; i++) { - fps[i] = (files[i].pid - ? open_temp (files[i].name, files[i].pid) + fps[i] = (files[i].temp && files[i].temp->state != UNCOMPRESSED + ? open_temp (files[i].temp) : stream_open (files[i].name, "r")); if (!fps[i]) break; @@ -3573,8 +3577,7 @@ avoid_trashing_input (struct sortfile *files, size_t ntemps, size_t i; bool got_outstat = false; struct stat outstat; - char const *tempcopy = NULL; - pid_t pid IF_LINT (= 0); + struct tempnode *tempcopy = NULL; for (i = ntemps; i < nfiles; i++) { @@ -3608,12 +3611,12 @@ avoid_trashing_input (struct sortfile *files, size_t ntemps, if (! tempcopy) { FILE *tftp; - tempcopy = create_temp (&tftp, &pid); - mergefiles (&files[i], 0, 1, tftp, tempcopy); + tempcopy = create_temp (&tftp); + mergefiles (&files[i], 0, 1, tftp, tempcopy->name); } - files[i].name = tempcopy; - files[i].pid = pid; + files[i].name = tempcopy->name; + files[i].temp = tempcopy; } } } @@ -3648,13 +3651,12 @@ merge (struct sortfile *files, size_t ntemps, size_t nfiles, for (out = in = 0; nmerge <= nfiles - in; out++) { FILE *tfp; - pid_t pid; - char *temp = create_temp (&tfp, &pid); + struct tempnode *temp = create_temp (&tfp); size_t num_merged = mergefiles (&files[in], MIN (ntemps, nmerge), - nmerge, tfp, temp); + nmerge, tfp, temp->name); ntemps -= MIN (ntemps, num_merged); - files[out].name = temp; - files[out].pid = pid; + files[out].name = temp->name; + files[out].temp = temp; in += num_merged; } @@ -3668,13 +3670,12 @@ merge (struct sortfile *files, size_t ntemps, size_t nfiles, files as possible, to avoid needless I/O. */ size_t nshortmerge = remainder - cheap_slots + 1; FILE *tfp; - pid_t pid; - char *temp = create_temp (&tfp, &pid); + struct tempnode *temp = create_temp (&tfp); size_t num_merged = mergefiles (&files[in], MIN (ntemps, nshortmerge), - nshortmerge, tfp, temp); + nshortmerge, tfp, temp->name); ntemps -= MIN (ntemps, num_merged); - files[out].name = temp; - files[out++].pid = pid; + files[out].name = temp->name; + files[out++].temp = temp; in += num_merged; } @@ -3717,21 +3718,21 @@ merge (struct sortfile *files, size_t ntemps, size_t nfiles, (e.g., some other process could open a file between the time we closed and tried to create). */ FILE *tfp; - pid_t pid; - char *temp; + struct tempnode *temp; do { nopened--; xfclose (fps[nopened], files[nopened].name); - temp = maybe_create_temp (&tfp, &pid, ! (nopened <= 2)); + temp = maybe_create_temp (&tfp, ! (nopened <= 2)); } while (!temp); /* Merge into the newly allocated temporary. */ - mergefps (&files[0], MIN (ntemps, nopened), nopened, tfp, temp, fps); + mergefps (&files[0], MIN (ntemps, nopened), nopened, tfp, temp->name, + fps); ntemps -= MIN (ntemps, nopened); - files[0].name = temp; - files[0].pid = pid; + files[0].name = temp->name; + files[0].temp = temp; memmove (&files[1], &files[nopened], (nfiles - nopened) * sizeof *files); ntemps++; @@ -3807,7 +3808,7 @@ sort (char *const *files, size_t nfiles, char const *output_file, else { ++ntemps; - temp_output = create_temp (&tfp, NULL); + temp_output = create_temp (&tfp)->name; } if (1 < buf.nlines) { @@ -3849,7 +3850,7 @@ sort (char *const *files, size_t nfiles, char const *output_file, for (i = 0; node; i++) { tempfiles[i].name = node->name; - tempfiles[i].pid = node->pid; + tempfiles[i].temp = node; node = node->next; } merge (tempfiles, ntemps, ntemps, output_file); |