diff options
Diffstat (limited to 'lib')
| -rw-r--r-- | lib/lib.h | 8 | ||||
| -rw-r--r-- | lib/xwrap.c | 78 |
2 files changed, 61 insertions, 25 deletions
@@ -95,8 +95,12 @@ void xflush(void); pid_t xfork(void); void xexec_optargs(int skip); void xexec(char **argv); -pid_t xpopen(char **argv, int *pipes); -int xpclose(pid_t pid, int *pipes); +pid_t xpopen_both(char **argv, int *pipes); +int xpclose_both(pid_t pid, int *pipes); +pid_t xpopen(char **argv, int *pipe, int stdout); +pid_t xpclose(pid_t pid, int pipe); +int xrun(char **argv); +int xpspawn(char **argv, int*pipes); void xaccess(char *path, int flags); void xunlink(char *path); int xcreate(char *path, int flags, int mode); diff --git a/lib/xwrap.c b/lib/xwrap.c index c9d1876f..64b183ff 100644 --- a/lib/xwrap.c +++ b/lib/xwrap.c @@ -145,33 +145,41 @@ void xexec(char **argv) // Spawn child process, capturing stdin/stdout. // argv[]: command to exec. If null, child returns to original program. -// pipes[]: stdin, stdout of new process. If null, block and wait for child. +// pipes[2]: stdin, stdout of new process. If -1 will not have pipe allocated. // return: pid of child process -pid_t xpopen(char **argv, int *pipes) +pid_t xpopen_both(char **argv, int *pipes) { int cestnepasun[4], pid; - // Make the pipes? + // Make the pipes? Not this won't set either pipe to 0 because if fds are + // allocated in order and if fd0 was free it would go to cestnepasun[0] if (pipes) { - if (pipe(cestnepasun) || pipe(cestnepasun+2)) perror_exit("pipe"); - pipes[0] = cestnepasun[1]; - pipes[1] = cestnepasun[2]; + for (pid = 0; pid < 2; pid++) { + if (pipes[pid] == -1) continue; + if (pipe(cestnepasun+(2*pid))) perror_exit("pipe"); + pipes[pid] = cestnepasun[pid+1]; + } } // Child process if (!(pid = xfork())) { // Dance of the stdin/stdout redirection. if (pipes) { - close(cestnepasun[1]); - close(cestnepasun[2]); - // if we had no stdin/out, pipe handles could overlap, so test for that - if (cestnepasun[0]) { - dup2(cestnepasun[0], 0); - close(cestnepasun[0]); + // if we had no stdin/out, pipe handles could overlap, so test for it + // and free up potentially overlapping pipe handles before reuse + if (pipes[1] != -1) close(cestnepasun[2]); + if (pipes[0] != -1) { + close(cestnepasun[1]); + if (cestnepasun[0]) { + dup2(cestnepasun[0], 0); + close(cestnepasun[0]); + } + } + if (pipes[1] != -1) { + dup2(cestnepasun[3], 1); + dup2(cestnepasun[3], 2); + if (cestnepasun[3] > 2 || !cestnepasun[3]) close(cestnepasun[3]); } - dup2(cestnepasun[3], 1); - dup2(cestnepasun[3], 2); - if (cestnepasun[3] > 2) close(cestnepasun[3]); } if (argv) { if (CFG_TOYBOX) toy_exec(argv); @@ -180,18 +188,18 @@ pid_t xpopen(char **argv, int *pipes) } return 0; - // Parent process - } else { - if (pipes) { - close(cestnepasun[0]); - close(cestnepasun[3]); - } + } - return pid; + // Parent process + if (pipes) { + if (pipes[0] != -1) close(cestnepasun[0]); + if (pipes[1] != -1) close(cestnepasun[3]); } + + return pid; } -int xpclose(pid_t pid, int *pipes) +int xpclose_both(pid_t pid, int *pipes) { int rc = 127; @@ -204,6 +212,30 @@ int xpclose(pid_t pid, int *pipes) return WIFEXITED(rc) ? WEXITSTATUS(rc) : WTERMSIG(rc) + 127; } +// Wrapper to xpopen with a pipe for just one of stdin/stdout +pid_t xpopen(char **argv, int *pipe, int stdout) +{ + int pipes[2]; + + pipe[!stdout] = -1; + pipe[!!stdout] = 0; + + return xpopen_both(argv, pipes); +} + +int xpclose(pid_t pid, int pipe) +{ + close(pipe); + + return xpclose_both(pid, 0); +} + +// Call xpopen and wait for it to finish, keeping existing stdin/stdout. +int xrun(char **argv) +{ + return xpclose_both(xpopen_both(argv, 0), 0); +} + void xaccess(char *path, int flags) { if (access(path, flags)) perror_exit("Can't access '%s'", path); |