diff options
| -rw-r--r-- | nq.c | 90 |
1 files changed, 44 insertions, 46 deletions
diff --git a/nq.c b/nq.c index 7611395..5636332 100644 --- a/nq.c +++ b/nq.c @@ -1,5 +1,5 @@ /* - ##% gcc -Wall -g -o $STEM $FILE +##% gcc -Wall -g -o $STEM $FILE */ #include <sys/file.h> @@ -17,39 +17,22 @@ #include <time.h> #include <unistd.h> -static void -quit(int sig) +void +swrite(int fd, char *str) { - exit(0); + if (write(fd, str, strlen(str)) < 0) { + perror("write"); + exit(222); + } } -/* - char * - timestamp() { - struct timeval tv; - gettimeofday(&tv, NULL); - static char buf[10]; - - int64_t ms = tv.tv_sec * 1000 + tv.tv_usec / 1000; - - buf[9] = 0; - int i; - for (i = 8; i >= 0; i--) { - buf[i] = 'a' + (ms % 26); - ms /= 26; - } - - return buf; - } -*/ - int main(int argc, char *argv[]) { pid_t child; - int lockfd; - char lockfile[128]; - int dirfd; + int lockfd, dirfd; + char lockfile[32]; + int pipefd[2]; struct timeval tv; gettimeofday(&tv, NULL); @@ -65,45 +48,58 @@ main(int argc, char *argv[]) exit(111); } + pipe(pipefd); + child = fork(); if (child == -1) { perror("fork"); exit(111); } - - if (child > 0) { + else if (child > 0) { // background - signal(SIGINT, quit); - pause(); + close(pipefd[1]); + char c; + read(pipefd[0], &c, 1); exit(0); } + close(pipefd[0]); + child = fork(); if (child == -1) { perror("fork"); exit(111); } - if (child > 0) { + else if (child > 0) { int status; sprintf(lockfile, ",%lx.%d", ms, child); - puts(lockfile); + dprintf(1, "%s\n", lockfile); // signal parent to exit - kill(getppid(), SIGINT); + close(pipefd[1]); wait(&status); - int fd; - fd = openat(dirfd, lockfile, O_RDWR | O_APPEND); - fchmod(fd, 0600); + + lockfd = openat(dirfd, lockfile, O_RDWR | O_APPEND); + if (lockfd < 0) { + perror("open"); + exit(222); + } + + fchmod(lockfd, 0600); if (WIFEXITED(status)) - dprintf(fd, "\n[exited with status %d.]\n", WEXITSTATUS(status)); + dprintf(lockfd, "\n[exited with status %d.]\n", + WEXITSTATUS(status)); else - dprintf(fd, "\n[killed by signal %d.]\n", WTERMSIG(status)); + dprintf(lockfd, "\n[killed by signal %d.]\n", + WTERMSIG(status)); exit(0); } + close(pipefd[1]); + sprintf(lockfile, ".,%lx.%d", ms, getpid()); lockfd = openat(dirfd, lockfile, O_CREAT | O_EXCL | O_RDWR | O_APPEND, 0600); @@ -114,21 +110,21 @@ main(int argc, char *argv[]) flock(lockfd, LOCK_EX); - // drop leading . + // drop leading '.' renameat(dirfd, lockfile, dirfd, lockfile+1); - write(lockfd, "exec", 4); + swrite(lockfd, "exec"); int i; for (i = 0; i < argc; i++) { int j, l = strlen(argv[i]); - write(lockfd, " '", 2); + swrite(lockfd, " '"); for (j = 0; j < l; j++) { if (argv[i][j] == '\'') - write(lockfd, "'\\''", 4); + swrite(lockfd, "'\\''"); else write(lockfd, argv[i]+j, 1); } - write(lockfd, "'", 1); + swrite(lockfd, "'"); } DIR *dir = fdopendir(dirfd); @@ -141,10 +137,12 @@ main(int argc, char *argv[]) again: while ((ent = readdir(dir))) { - if (ent->d_name[0] == ',' && strcmp(ent->d_name, lockfile+1) < 0) { + if (ent->d_name[0] == ',' && + strcmp(ent->d_name, lockfile+1) < 0) { int f = openat(dirfd, ent->d_name, O_RDWR); - if (flock(f, LOCK_EX | LOCK_NB) == -1 && errno == EWOULDBLOCK) { + if (flock(f, LOCK_EX | LOCK_NB) == -1 && + errno == EWOULDBLOCK) { flock(f, LOCK_EX); // sit it out rewinddir(dir); |