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Another sh.c patch from Larry Doolittle. This makes redirects work properly

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with non-forking shell builtins.  Especially helpful for "read".  This patch
also beautifies builtin_fg_bg, clarifies the problems with
run_command_predicate, makes if/then/else support the default, and corrects the
sense of the BB_FEATURE_SH_ENVIRONMENT comment.
This commit is contained in:
Eric Andersen 2000-12-21 18:31:36 +00:00
parent 16fdbe8b27
commit e9f07fb6e8
3 changed files with 213 additions and 111 deletions
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78
lash.c
View File

@ -26,7 +26,7 @@
*/ */
// //
//This works pretty well now, and is not on by default. //This works pretty well now, and is now on by default.
#define BB_FEATURE_SH_ENVIRONMENT #define BB_FEATURE_SH_ENVIRONMENT
// //
//Backtick support has some problems, use at your own risk! //Backtick support has some problems, use at your own risk!
@ -34,7 +34,7 @@
// //
//If, then, else, etc. support.. This should now behave basically //If, then, else, etc. support.. This should now behave basically
//like any other Bourne shell... //like any other Bourne shell...
//#define BB_FEATURE_SH_IF_EXPRESSIONS #define BB_FEATURE_SH_IF_EXPRESSIONS
// //
/* This is currently a little broken... */ /* This is currently a little broken... */
//#define HANDLE_CONTINUATION_CHARS //#define HANDLE_CONTINUATION_CHARS
@ -316,17 +316,18 @@ static int builtin_fg_bg(struct child_prog *child)
int i, jobNum; int i, jobNum;
struct job *job=NULL; struct job *job=NULL;
if (!child->argv[1] || child->argv[2]) { if (!child->argv[1] || child->argv[2]) {
error_msg("%s: exactly one argument is expected\n", error_msg("%s: exactly one argument is expected\n",
child->argv[0]); child->argv[0]);
return EXIT_FAILURE; return EXIT_FAILURE;
} }
if (sscanf(child->argv[1], "%%%d", &jobNum) != 1) { if (sscanf(child->argv[1], "%%%d", &jobNum) != 1) {
error_msg("%s: bad argument '%s'\n", error_msg("%s: bad argument '%s'\n",
child->argv[0], child->argv[1]); child->argv[0], child->argv[1]);
return EXIT_FAILURE; return EXIT_FAILURE;
} }
for (job = child->family->job_list->head; job; job = job->next) { for (job = child->family->job_list->head; job; job = job->next) {
if (job->jobid == jobNum) { if (job->jobid == jobNum) {
break; break;
@ -524,7 +525,7 @@ static int builtin_else(struct child_prog *child)
} }
cmd->job_context |= ELSE_EXP_CONTEXT; cmd->job_context |= ELSE_EXP_CONTEXT;
debug_printf("job=%p builtin_else set job context to %x\n", child->family, cmd->job_context); debug_printf("job=%p builtin_else set job context to %x\n", cmd, cmd->job_context);
/* Now run the 'else' command */ /* Now run the 'else' command */
debug_printf( "'else' now running '%s'\n", charptr1); debug_printf( "'else' now running '%s'\n", charptr1);
@ -583,12 +584,13 @@ static int builtin_unset(struct child_prog *child)
#ifdef BB_FEATURE_SH_IF_EXPRESSIONS #ifdef BB_FEATURE_SH_IF_EXPRESSIONS
/* currently used by if/then/else. /* currently used by if/then/else.
* Needlessly (?) forks and reparses the command line. *
* But pseudo_exec on the pre-parsed args doesn't have the * Reparsing the command line for this purpose is gross,
* "fork, stick around until the child exits, and find it's return code" * incorrect, and fundamentally unfixable; in particular,
* functionality. The fork is not needed if the predicate is * think about what happens with command substitution.
* non-forking builtin, and maybe not even if it's a forking builtin. * We really need to pull out the run, wait, return status
* applets pretty clearly need the fork. * functionality out of busy_loop so we can child->argv++
* and use that, without going back through parse_command.
*/ */
static int run_command_predicate(char *cmd) static int run_command_predicate(char *cmd)
{ {
@ -684,7 +686,9 @@ static void checkjobs(struct jobset *job_list)
perror("waitpid"); perror("waitpid");
} }
static int setup_redirects(struct child_prog *prog) /* squirrel != NULL means we squirrel away copies of stdin, stdout,
* and stderr if they are redirected. */
static int setup_redirects(struct child_prog *prog, int squirrel[])
{ {
int i; int i;
int openfd; int openfd;
@ -714,6 +718,9 @@ static int setup_redirects(struct child_prog *prog)
} }
if (openfd != redir->fd) { if (openfd != redir->fd) {
if (squirrel && redir->fd < 3) {
squirrel[redir->fd] = dup(redir->fd);
}
dup2(openfd, redir->fd); dup2(openfd, redir->fd);
close(openfd); close(openfd);
} }
@ -722,6 +729,19 @@ static int setup_redirects(struct child_prog *prog)
return 0; return 0;
} }
static void restore_redirects(int squirrel[])
{
int i, fd;
for (i=0; i<3; i++) {
fd = squirrel[i];
if (fd != -1) {
/* No error checking. I sure wouldn't know what
* to do with an error if I found one! */
dup2(fd, i);
close(fd);
}
}
}
static int get_command(FILE * source, char *command) static int get_command(FILE * source, char *command)
{ {
@ -1304,11 +1324,18 @@ static int pseudo_exec(struct child_prog *child)
struct BB_applet search_applet, *applet; struct BB_applet search_applet, *applet;
#endif #endif
/* Check if the command matches any of the forking builtins. /* Check if the command matches any of the non-forking builtins.
* XXX It would probably be wise to check for non-forking builtins * Depending on context, this might be redundant. But it's
* here as well, since in some context the non-forking path * easier to waste a few CPU cycles than it is to figure out
* is disabled or bypassed. See comment in run_command. * if this is one of those cases.
*/ */
for (x = bltins; x->cmd; x++) {
if (strcmp(child->argv[0], x->cmd) == 0 ) {
exit(x->function(child));
}
}
/* Check if the command matches any of the forking builtins. */
for (x = bltins_forking; x->cmd; x++) { for (x = bltins_forking; x->cmd; x++) {
if (strcmp(child->argv[0], x->cmd) == 0) { if (strcmp(child->argv[0], x->cmd) == 0) {
applet_name=x->cmd; applet_name=x->cmd;
@ -1435,15 +1462,22 @@ static int run_command(struct job *newjob, int inbg, int outpipe[2])
} }
#endif #endif
/* Check if the command matches any non-forking builtins. /* Check if the command matches any non-forking builtins,
* XXX should probably skip this test, and fork anyway, if * but only if this is a simple command.
* there redirects of some kind demand forking to work right. * Non-forking builtins within pipes have to fork anyway,
* pseudo_exec would then need to handle the non-forking command * and are handled in pseudo_exec. "echo foo | read bar"
* in a forked context. * is doomed to failure, and doesn't work on bash, either.
*/ */
if (newjob->num_progs == 1) {
for (x = bltins; x->cmd; x++) { for (x = bltins; x->cmd; x++) {
if (strcmp(child->argv[0], x->cmd) == 0 ) { if (strcmp(child->argv[0], x->cmd) == 0 ) {
return(x->function(child)); int squirrel[] = {-1, -1, -1};
int rcode;
setup_redirects(child, squirrel);
rcode = x->function(child);
restore_redirects(squirrel);
return rcode;
}
} }
} }
@ -1466,7 +1500,7 @@ static int run_command(struct job *newjob, int inbg, int outpipe[2])
} }
/* explicit redirects override pipes */ /* explicit redirects override pipes */
setup_redirects(child); setup_redirects(child,NULL);
pseudo_exec(child); pseudo_exec(child);
} }

78
sh.c
View File

@ -26,7 +26,7 @@
*/ */
// //
//This works pretty well now, and is not on by default. //This works pretty well now, and is now on by default.
#define BB_FEATURE_SH_ENVIRONMENT #define BB_FEATURE_SH_ENVIRONMENT
// //
//Backtick support has some problems, use at your own risk! //Backtick support has some problems, use at your own risk!
@ -34,7 +34,7 @@
// //
//If, then, else, etc. support.. This should now behave basically //If, then, else, etc. support.. This should now behave basically
//like any other Bourne shell... //like any other Bourne shell...
//#define BB_FEATURE_SH_IF_EXPRESSIONS #define BB_FEATURE_SH_IF_EXPRESSIONS
// //
/* This is currently a little broken... */ /* This is currently a little broken... */
//#define HANDLE_CONTINUATION_CHARS //#define HANDLE_CONTINUATION_CHARS
@ -316,17 +316,18 @@ static int builtin_fg_bg(struct child_prog *child)
int i, jobNum; int i, jobNum;
struct job *job=NULL; struct job *job=NULL;
if (!child->argv[1] || child->argv[2]) { if (!child->argv[1] || child->argv[2]) {
error_msg("%s: exactly one argument is expected\n", error_msg("%s: exactly one argument is expected\n",
child->argv[0]); child->argv[0]);
return EXIT_FAILURE; return EXIT_FAILURE;
} }
if (sscanf(child->argv[1], "%%%d", &jobNum) != 1) { if (sscanf(child->argv[1], "%%%d", &jobNum) != 1) {
error_msg("%s: bad argument '%s'\n", error_msg("%s: bad argument '%s'\n",
child->argv[0], child->argv[1]); child->argv[0], child->argv[1]);
return EXIT_FAILURE; return EXIT_FAILURE;
} }
for (job = child->family->job_list->head; job; job = job->next) { for (job = child->family->job_list->head; job; job = job->next) {
if (job->jobid == jobNum) { if (job->jobid == jobNum) {
break; break;
@ -524,7 +525,7 @@ static int builtin_else(struct child_prog *child)
} }
cmd->job_context |= ELSE_EXP_CONTEXT; cmd->job_context |= ELSE_EXP_CONTEXT;
debug_printf("job=%p builtin_else set job context to %x\n", child->family, cmd->job_context); debug_printf("job=%p builtin_else set job context to %x\n", cmd, cmd->job_context);
/* Now run the 'else' command */ /* Now run the 'else' command */
debug_printf( "'else' now running '%s'\n", charptr1); debug_printf( "'else' now running '%s'\n", charptr1);
@ -583,12 +584,13 @@ static int builtin_unset(struct child_prog *child)
#ifdef BB_FEATURE_SH_IF_EXPRESSIONS #ifdef BB_FEATURE_SH_IF_EXPRESSIONS
/* currently used by if/then/else. /* currently used by if/then/else.
* Needlessly (?) forks and reparses the command line. *
* But pseudo_exec on the pre-parsed args doesn't have the * Reparsing the command line for this purpose is gross,
* "fork, stick around until the child exits, and find it's return code" * incorrect, and fundamentally unfixable; in particular,
* functionality. The fork is not needed if the predicate is * think about what happens with command substitution.
* non-forking builtin, and maybe not even if it's a forking builtin. * We really need to pull out the run, wait, return status
* applets pretty clearly need the fork. * functionality out of busy_loop so we can child->argv++
* and use that, without going back through parse_command.
*/ */
static int run_command_predicate(char *cmd) static int run_command_predicate(char *cmd)
{ {
@ -684,7 +686,9 @@ static void checkjobs(struct jobset *job_list)
perror("waitpid"); perror("waitpid");
} }
static int setup_redirects(struct child_prog *prog) /* squirrel != NULL means we squirrel away copies of stdin, stdout,
* and stderr if they are redirected. */
static int setup_redirects(struct child_prog *prog, int squirrel[])
{ {
int i; int i;
int openfd; int openfd;
@ -714,6 +718,9 @@ static int setup_redirects(struct child_prog *prog)
} }
if (openfd != redir->fd) { if (openfd != redir->fd) {
if (squirrel && redir->fd < 3) {
squirrel[redir->fd] = dup(redir->fd);
}
dup2(openfd, redir->fd); dup2(openfd, redir->fd);
close(openfd); close(openfd);
} }
@ -722,6 +729,19 @@ static int setup_redirects(struct child_prog *prog)
return 0; return 0;
} }
static void restore_redirects(int squirrel[])
{
int i, fd;
for (i=0; i<3; i++) {
fd = squirrel[i];
if (fd != -1) {
/* No error checking. I sure wouldn't know what
* to do with an error if I found one! */
dup2(fd, i);
close(fd);
}
}
}
static int get_command(FILE * source, char *command) static int get_command(FILE * source, char *command)
{ {
@ -1304,11 +1324,18 @@ static int pseudo_exec(struct child_prog *child)
struct BB_applet search_applet, *applet; struct BB_applet search_applet, *applet;
#endif #endif
/* Check if the command matches any of the forking builtins. /* Check if the command matches any of the non-forking builtins.
* XXX It would probably be wise to check for non-forking builtins * Depending on context, this might be redundant. But it's
* here as well, since in some context the non-forking path * easier to waste a few CPU cycles than it is to figure out
* is disabled or bypassed. See comment in run_command. * if this is one of those cases.
*/ */
for (x = bltins; x->cmd; x++) {
if (strcmp(child->argv[0], x->cmd) == 0 ) {
exit(x->function(child));
}
}
/* Check if the command matches any of the forking builtins. */
for (x = bltins_forking; x->cmd; x++) { for (x = bltins_forking; x->cmd; x++) {
if (strcmp(child->argv[0], x->cmd) == 0) { if (strcmp(child->argv[0], x->cmd) == 0) {
applet_name=x->cmd; applet_name=x->cmd;
@ -1435,15 +1462,22 @@ static int run_command(struct job *newjob, int inbg, int outpipe[2])
} }
#endif #endif
/* Check if the command matches any non-forking builtins. /* Check if the command matches any non-forking builtins,
* XXX should probably skip this test, and fork anyway, if * but only if this is a simple command.
* there redirects of some kind demand forking to work right. * Non-forking builtins within pipes have to fork anyway,
* pseudo_exec would then need to handle the non-forking command * and are handled in pseudo_exec. "echo foo | read bar"
* in a forked context. * is doomed to failure, and doesn't work on bash, either.
*/ */
if (newjob->num_progs == 1) {
for (x = bltins; x->cmd; x++) { for (x = bltins; x->cmd; x++) {
if (strcmp(child->argv[0], x->cmd) == 0 ) { if (strcmp(child->argv[0], x->cmd) == 0 ) {
return(x->function(child)); int squirrel[] = {-1, -1, -1};
int rcode;
setup_redirects(child, squirrel);
rcode = x->function(child);
restore_redirects(squirrel);
return rcode;
}
} }
} }
@ -1466,7 +1500,7 @@ static int run_command(struct job *newjob, int inbg, int outpipe[2])
} }
/* explicit redirects override pipes */ /* explicit redirects override pipes */
setup_redirects(child); setup_redirects(child,NULL);
pseudo_exec(child); pseudo_exec(child);
} }

78
shell/lash.c
View File

@ -26,7 +26,7 @@
*/ */
// //
//This works pretty well now, and is not on by default. //This works pretty well now, and is now on by default.
#define BB_FEATURE_SH_ENVIRONMENT #define BB_FEATURE_SH_ENVIRONMENT
// //
//Backtick support has some problems, use at your own risk! //Backtick support has some problems, use at your own risk!
@ -34,7 +34,7 @@
// //
//If, then, else, etc. support.. This should now behave basically //If, then, else, etc. support.. This should now behave basically
//like any other Bourne shell... //like any other Bourne shell...
//#define BB_FEATURE_SH_IF_EXPRESSIONS #define BB_FEATURE_SH_IF_EXPRESSIONS
// //
/* This is currently a little broken... */ /* This is currently a little broken... */
//#define HANDLE_CONTINUATION_CHARS //#define HANDLE_CONTINUATION_CHARS
@ -316,17 +316,18 @@ static int builtin_fg_bg(struct child_prog *child)
int i, jobNum; int i, jobNum;
struct job *job=NULL; struct job *job=NULL;
if (!child->argv[1] || child->argv[2]) { if (!child->argv[1] || child->argv[2]) {
error_msg("%s: exactly one argument is expected\n", error_msg("%s: exactly one argument is expected\n",
child->argv[0]); child->argv[0]);
return EXIT_FAILURE; return EXIT_FAILURE;
} }
if (sscanf(child->argv[1], "%%%d", &jobNum) != 1) { if (sscanf(child->argv[1], "%%%d", &jobNum) != 1) {
error_msg("%s: bad argument '%s'\n", error_msg("%s: bad argument '%s'\n",
child->argv[0], child->argv[1]); child->argv[0], child->argv[1]);
return EXIT_FAILURE; return EXIT_FAILURE;
} }
for (job = child->family->job_list->head; job; job = job->next) { for (job = child->family->job_list->head; job; job = job->next) {
if (job->jobid == jobNum) { if (job->jobid == jobNum) {
break; break;
@ -524,7 +525,7 @@ static int builtin_else(struct child_prog *child)
} }
cmd->job_context |= ELSE_EXP_CONTEXT; cmd->job_context |= ELSE_EXP_CONTEXT;
debug_printf("job=%p builtin_else set job context to %x\n", child->family, cmd->job_context); debug_printf("job=%p builtin_else set job context to %x\n", cmd, cmd->job_context);
/* Now run the 'else' command */ /* Now run the 'else' command */
debug_printf( "'else' now running '%s'\n", charptr1); debug_printf( "'else' now running '%s'\n", charptr1);
@ -583,12 +584,13 @@ static int builtin_unset(struct child_prog *child)
#ifdef BB_FEATURE_SH_IF_EXPRESSIONS #ifdef BB_FEATURE_SH_IF_EXPRESSIONS
/* currently used by if/then/else. /* currently used by if/then/else.
* Needlessly (?) forks and reparses the command line. *
* But pseudo_exec on the pre-parsed args doesn't have the * Reparsing the command line for this purpose is gross,
* "fork, stick around until the child exits, and find it's return code" * incorrect, and fundamentally unfixable; in particular,
* functionality. The fork is not needed if the predicate is * think about what happens with command substitution.
* non-forking builtin, and maybe not even if it's a forking builtin. * We really need to pull out the run, wait, return status
* applets pretty clearly need the fork. * functionality out of busy_loop so we can child->argv++
* and use that, without going back through parse_command.
*/ */
static int run_command_predicate(char *cmd) static int run_command_predicate(char *cmd)
{ {
@ -684,7 +686,9 @@ static void checkjobs(struct jobset *job_list)
perror("waitpid"); perror("waitpid");
} }
static int setup_redirects(struct child_prog *prog) /* squirrel != NULL means we squirrel away copies of stdin, stdout,
* and stderr if they are redirected. */
static int setup_redirects(struct child_prog *prog, int squirrel[])
{ {
int i; int i;
int openfd; int openfd;
@ -714,6 +718,9 @@ static int setup_redirects(struct child_prog *prog)
} }
if (openfd != redir->fd) { if (openfd != redir->fd) {
if (squirrel && redir->fd < 3) {
squirrel[redir->fd] = dup(redir->fd);
}
dup2(openfd, redir->fd); dup2(openfd, redir->fd);
close(openfd); close(openfd);
} }
@ -722,6 +729,19 @@ static int setup_redirects(struct child_prog *prog)
return 0; return 0;
} }
static void restore_redirects(int squirrel[])
{
int i, fd;
for (i=0; i<3; i++) {
fd = squirrel[i];
if (fd != -1) {
/* No error checking. I sure wouldn't know what
* to do with an error if I found one! */
dup2(fd, i);
close(fd);
}
}
}
static int get_command(FILE * source, char *command) static int get_command(FILE * source, char *command)
{ {
@ -1304,11 +1324,18 @@ static int pseudo_exec(struct child_prog *child)
struct BB_applet search_applet, *applet; struct BB_applet search_applet, *applet;
#endif #endif
/* Check if the command matches any of the forking builtins. /* Check if the command matches any of the non-forking builtins.
* XXX It would probably be wise to check for non-forking builtins * Depending on context, this might be redundant. But it's
* here as well, since in some context the non-forking path * easier to waste a few CPU cycles than it is to figure out
* is disabled or bypassed. See comment in run_command. * if this is one of those cases.
*/ */
for (x = bltins; x->cmd; x++) {
if (strcmp(child->argv[0], x->cmd) == 0 ) {
exit(x->function(child));
}
}
/* Check if the command matches any of the forking builtins. */
for (x = bltins_forking; x->cmd; x++) { for (x = bltins_forking; x->cmd; x++) {
if (strcmp(child->argv[0], x->cmd) == 0) { if (strcmp(child->argv[0], x->cmd) == 0) {
applet_name=x->cmd; applet_name=x->cmd;
@ -1435,15 +1462,22 @@ static int run_command(struct job *newjob, int inbg, int outpipe[2])
} }
#endif #endif
/* Check if the command matches any non-forking builtins. /* Check if the command matches any non-forking builtins,
* XXX should probably skip this test, and fork anyway, if * but only if this is a simple command.
* there redirects of some kind demand forking to work right. * Non-forking builtins within pipes have to fork anyway,
* pseudo_exec would then need to handle the non-forking command * and are handled in pseudo_exec. "echo foo | read bar"
* in a forked context. * is doomed to failure, and doesn't work on bash, either.
*/ */
if (newjob->num_progs == 1) {
for (x = bltins; x->cmd; x++) { for (x = bltins; x->cmd; x++) {
if (strcmp(child->argv[0], x->cmd) == 0 ) { if (strcmp(child->argv[0], x->cmd) == 0 ) {
return(x->function(child)); int squirrel[] = {-1, -1, -1};
int rcode;
setup_redirects(child, squirrel);
rcode = x->function(child);
restore_redirects(squirrel);
return rcode;
}
} }
} }
@ -1466,7 +1500,7 @@ static int run_command(struct job *newjob, int inbg, int outpipe[2])
} }
/* explicit redirects override pipes */ /* explicit redirects override pipes */
setup_redirects(child); setup_redirects(child,NULL);
pseudo_exec(child); pseudo_exec(child);
} }