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authorRob Landley <rob@landley.net>2014-09-14 12:29:44 -0500
committerRob Landley <rob@landley.net>2014-09-14 12:29:44 -0500
commit360d57f843f5435a75270e54583430dcb8f62546 (patch)
tree2e043033414a0cb03b6eb86b3b662f7ca9571788 /lib
parente1366f02fea3cb035cc4ed0b59d12f1962b6ebfd (diff)
downloadtoybox-360d57f843f5435a75270e54583430dcb8f62546.tar.gz
Split xpopen() into xpopen_both(), xpopen(), and xrun() depending on whether we want to redirect both, one, or neither of stdin/stdout.
Diffstat (limited to 'lib')
-rw-r--r--lib/lib.h8
-rw-r--r--lib/xwrap.c78
2 files changed, 61 insertions, 25 deletions
diff --git a/lib/lib.h b/lib/lib.h
index b93e19bc..887c1d57 100644
--- a/lib/lib.h
+++ b/lib/lib.h
@@ -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);