This patch adds basic vfork support for the case of a simple command.
Signed-off-by: Herbert Xu <herb...@gondor.apana.org.au>
---
src/error.c | 5 +++
src/eval.c | 6 +---
src/exec.h | 2 +
src/jobs.c | 86 ++++++++++++++++++++++++++++++++++++++++++++++--------------
src/jobs.h | 4 ++
src/trap.c | 22 +++++++++++++--
src/trap.h | 1
7 files changed, 99 insertions(+), 27 deletions(-)
diff --git a/src/error.c b/src/error.c
index f9ea919..728ff88 100644
--- a/src/error.c
+++ b/src/error.c
@@ -43,6 +43,7 @@
#include <stdio.h>
#include <string.h>
+#include "jobs.h"
#include "shell.h"
#include "main.h"
#include "options.h"
@@ -81,6 +82,10 @@ exraise(int e)
if (handler == NULL)
abort();
#endif
+
+ if (vforked)
+ _exit(exitstatus);
+
INTOFF;
exception = e;
diff --git a/src/eval.c b/src/eval.c
index c160500..ad20e80 100644
--- a/src/eval.c
+++ b/src/eval.c
@@ -864,10 +864,8 @@ bail:
/* Fork off a child process if necessary. */
if (!(flags & EV_EXIT) || have_traps()) {
INTOFF;
- jp = makejob(cmd, 1);
- if (forkshell(jp, cmd, FORK_FG) != 0)
- break;
- FORCEINTON;
+ jp = vforkexec(cmd, argv, path, cmdentry.u.index);
+ break;
}
shellexec(argv, path, cmdentry.u.index);
/* NOTREACHED */
diff --git a/src/exec.h b/src/exec.h
index 9ccb305..5317451 100644
--- a/src/exec.h
+++ b/src/exec.h
@@ -58,6 +58,8 @@ struct cmdentry {
#define DO_ALTPATH 0x08 /* using alternate path */
#define DO_ALTBLTIN 0x20 /* %builtin in alt. path */
+union node;
+
extern const char *pathopt; /* set by padvance */
void shellexec(char **, const char *, int)
diff --git a/src/jobs.c b/src/jobs.c
index 601232d..f3a0d80 100644
--- a/src/jobs.c
+++ b/src/jobs.c
@@ -53,6 +53,7 @@
#include <termios.h>
#undef CEOF /* syntax.h redefines this */
#endif
+#include "exec.h"
#include "eval.h"
#include "redir.h"
#include "show.h"
@@ -97,6 +98,9 @@ static int ttyfd = -1;
/* current job */
static struct job *curjob;
+/* Set if we are in the vforked child */
+int vforked;
+
STATIC void set_curjob(struct job *, unsigned);
STATIC int jobno(const struct job *);
STATIC int sprint_status(char *, int, int);
@@ -840,20 +844,29 @@ growjobtab(void)
* Called with interrupts off.
*/
-STATIC inline void
-forkchild(struct job *jp, union node *n, int mode)
+static void forkchild(struct job *jp, union node *n, int mode)
{
+ int lvforked;
int oldlvl;
TRACE(("Child shell %d\n", getpid()));
+
oldlvl = shlvl;
- shlvl++;
+ lvforked = vforked;
+
+ if (!lvforked) {
+ shlvl++;
+
+ closescript();
+ clear_traps();
+
+#if JOBS
+ /* do job control only in root shell */
+ jobctl = 0;
+#endif
+ }
- closescript();
- clear_traps();
#if JOBS
- /* do job control only in root shell */
- jobctl = 0;
if (mode != FORK_NOJOB && jp->jobctl && !oldlvl) {
pid_t pgrp;
@@ -879,17 +892,30 @@ forkchild(struct job *jp, union node *n, int mode)
}
}
if (!oldlvl && iflag) {
- setsignal(SIGINT);
- setsignal(SIGQUIT);
+ if (mode != FORK_BG) {
+ setsignal(SIGINT);
+ setsignal(SIGQUIT);
+ }
setsignal(SIGTERM);
}
+
+ if (lvforked)
+ return;
+
for (jp = curjob; jp; jp = jp->prev_job)
freejob(jp);
}
-STATIC inline void
-forkparent(struct job *jp, union node *n, int mode, pid_t pid)
+static void forkparent(struct job *jp, union node *n, int mode, pid_t pid)
{
+ if (pid < 0) {
+ TRACE(("Fork failed, errno=%d", errno));
+ if (jp)
+ freejob(jp);
+ sh_error("Cannot fork");
+ /* NOTREACHED */
+ }
+
TRACE(("In parent shell: child = %d\n", pid));
if (!jp)
return;
@@ -926,19 +952,40 @@ forkshell(struct job *jp, union node *n, int mode)
TRACE(("forkshell(%%%d, %p, %d) called\n", jobno(jp), n, mode));
pid = fork();
- if (pid < 0) {
- TRACE(("Fork failed, errno=%d", errno));
- if (jp)
- freejob(jp);
- sh_error("Cannot fork");
- }
if (pid == 0)
forkchild(jp, n, mode);
else
forkparent(jp, n, mode, pid);
+
return pid;
}
+struct job *vforkexec(union node *n, char **argv, const char *path, int idx)
+{
+ struct job *jp;
+ int pid;
+
+ jp = makejob(n, 1);
+
+ sigblockall(NULL);
+ vforked++;
+
+ pid = vfork();
+
+ if (!pid) {
+ forkchild(jp, n, FORK_FG);
+ sigclearmask();
+ shellexec(argv, path, idx);
+ /* NOTREACHED */
+ }
+
+ vforked = 0;
+ sigclearmask();
+ forkparent(jp, n, FORK_FG, pid);
+
+ return jp;
+}
+
/*
* Wait for job to finish.
*
@@ -1106,7 +1153,7 @@ static int dowait(int block, struct job *jp)
STATIC int
waitproc(int block, int *status)
{
- sigset_t mask, oldmask;
+ sigset_t oldmask;
int flags = block == DOWAIT_BLOCK ? 0 : WNOHANG;
int err;
@@ -1120,8 +1167,7 @@ waitproc(int block, int *status)
if (err || (err = -!block))
break;
- sigfillset(&mask);
- sigprocmask(SIG_SETMASK, &mask, &oldmask);
+ sigblockall(&oldmask);
while (!gotsigchld && !pending_sig)
sigsuspend(&oldmask);
diff --git a/src/jobs.h b/src/jobs.h
index 953ee87..6ac6c56 100644
--- a/src/jobs.h
+++ b/src/jobs.h
@@ -83,6 +83,8 @@ struct job {
struct job *prev_job; /* previous job */
};
+union node;
+
extern pid_t backgndpid; /* pid of last background process */
extern int job_warning; /* user was warned about stopped jobs */
#if JOBS
@@ -90,6 +92,7 @@ extern int jobctl; /* true if doing job control */
#else
#define jobctl 0
#endif
+extern int vforked; /* Set if we are in the vforked child */
void setjobctl(int);
int killcmd(int, char **);
@@ -101,6 +104,7 @@ void showjobs(struct output *, int);
int waitcmd(int, char **);
struct job *makejob(union node *, int);
int forkshell(struct job *, union node *, int);
+struct job *vforkexec(union node *n, char **argv, const char *path, int idx);
int waitforjob(struct job *);
int stoppedjobs(void);
diff --git a/src/trap.c b/src/trap.c
index 69eb8ab..ab0ecd4 100644
--- a/src/trap.c
+++ b/src/trap.c
@@ -182,16 +182,19 @@ void
setsignal(int signo)
{
int action;
+ int lvforked;
char *t, tsig;
struct sigaction act;
+ lvforked = vforked;
+
if ((t = trap[signo]) == NULL)
action = S_DFL;
else if (*t != '\0')
action = S_CATCH;
else
action = S_IGN;
- if (rootshell && action == S_DFL) {
+ if (rootshell && action == S_DFL && !lvforked) {
switch (signo) {
case SIGINT:
if (iflag || minusc || sflag == 0)
@@ -256,7 +259,8 @@ setsignal(int signo)
default:
act.sa_handler = SIG_DFL;
}
- *t = action;
+ if (!lvforked)
+ *t = action;
act.sa_flags = 0;
sigfillset(&act.sa_mask);
sigaction(signo, &act, 0);
@@ -272,7 +276,8 @@ ignoresig(int signo)
if (sigmode[signo - 1] != S_IGN && sigmode[signo - 1] != S_HARD_IGN) {
signal(signo, SIG_IGN);
}
- sigmode[signo - 1] = S_HARD_IGN;
+ if (!vforked)
+ sigmode[signo - 1] = S_HARD_IGN;
}
@@ -284,6 +289,9 @@ ignoresig(int signo)
void
onsig(int signo)
{
+ if (vforked)
+ return;
+
if (signo == SIGCHLD) {
gotsigchld = 1;
if (!trap[SIGCHLD])
@@ -431,3 +439,11 @@ int decode_signal(const char *string, int minsig)
return -1;
}
+
+void sigblockall(sigset_t *oldmask)
+{
+ sigset_t mask;
+
+ sigfillset(&mask);
+ sigprocmask(SIG_SETMASK, &mask, oldmask);
+}
diff --git a/src/trap.h b/src/trap.h
index b9dfcf2..5fd65af 100644
--- a/src/trap.h
+++ b/src/trap.h
@@ -50,6 +50,7 @@ void dotrap(void);
void setinteractive(int);
void exitshell(void) __attribute__((__noreturn__));
int decode_signal(const char *, int);
+void sigblockall(sigset_t *oldmask);
static inline int have_traps(void)
{
--
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