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-rw-r--r--sh.c161
1 files changed, 123 insertions, 38 deletions
diff --git a/sh.c b/sh.c
index 6029eaa..b2d1d43 100644
--- a/sh.c
+++ b/sh.c
@@ -27,6 +27,7 @@
#define BB_FEATURE_SH_BACKTICKS
+//#define BB_FEATURE_SH_IF_EXPRESSIONS
@@ -55,6 +56,14 @@ enum redirectionType { REDIRECT_INPUT, REDIRECT_OVERWRITE,
REDIRECT_APPEND
};
+#define REGULAR_JOB_CONTEXT 0x1
+#define IF_EXP_CONTEXT 0x2
+#define THEN_EXP_CONTEXT 0x4
+#define ELSE_EXP_CONTEXT 0x8
+
+enum jobContext { REGULAR_APP, IF_CONTEXT, THEN_CONTEXT
+};
+
struct jobSet {
struct job *head; /* head of list of running jobs */
struct job *fg; /* current foreground job */
@@ -86,12 +95,12 @@ struct job {
struct childProgram *progs; /* array of programs in job */
struct job *next; /* to track background commands */
int stoppedProgs; /* number of programs alive, but stopped */
+ int jobContext; /* bitmask defining current context */
};
struct builtInCommand {
char *cmd; /* name */
char *descr; /* description */
- char *usage; /* usage */
int (*function) (struct job *, struct jobSet * jobList); /* function ptr */
};
@@ -107,6 +116,12 @@ static int builtin_export(struct job *cmd, struct jobSet *junk);
static int builtin_source(struct job *cmd, struct jobSet *jobList);
static int builtin_unset(struct job *cmd, struct jobSet *junk);
static int builtin_read(struct job *cmd, struct jobSet *junk);
+#ifdef BB_FEATURE_SH_IF_EXPRESSIONS
+static int builtin_if(struct job *cmd, struct jobSet *junk);
+static int builtin_then(struct job *cmd, struct jobSet *junk);
+static int builtin_else(struct job *cmd, struct jobSet *junk);
+static int builtin_fi(struct job *cmd, struct jobSet *junk);
+#endif
/* function prototypes for shell stuff */
@@ -122,30 +137,38 @@ static int busy_loop(FILE * input);
* can change global variables in the parent shell process but they will not
* work with pipes and redirects; 'unset foo | whatever' will not work) */
static struct builtInCommand bltins[] = {
- {"bg", "Resume a job in the background", "bg [%%job]", builtin_fg_bg},
- {"cd", "Change working directory", "cd [dir]", builtin_cd},
- {"exit", "Exit from shell()", "exit", builtin_exit},
- {"fg", "Bring job into the foreground", "fg [%%job]", builtin_fg_bg},
- {"jobs", "Lists the active jobs", "jobs", builtin_jobs},
- {"export", "Set environment variable", "export [VAR=value]", builtin_export},
- {"unset", "Unset environment variable", "unset VAR", builtin_unset},
- {"read", "Input environment variable", "read [VAR]", builtin_read},
- {NULL, NULL, NULL, NULL}
+ {"bg", "Resume a job in the background", builtin_fg_bg},
+ {"cd", "Change working directory", builtin_cd},
+ {"exit", "Exit from shell()", builtin_exit},
+ {"fg", "Bring job into the foreground", builtin_fg_bg},
+ {"jobs", "Lists the active jobs", builtin_jobs},
+ {"export", "Set environment variable", builtin_export},
+ {"unset", "Unset environment variable", builtin_unset},
+ {"read", "Input environment variable", builtin_read},
+ {NULL, NULL, NULL}
};
/* Table of forking built-in functions (things that fork cannot change global
* variables in the parent process, such as the current working directory) */
static struct builtInCommand bltins_forking[] = {
- {"env", "Print all environment variables", "env", builtin_env},
- {"pwd", "Print current directory", "pwd", builtin_pwd},
- {".", "Source-in and run commands in a file", ". filename", builtin_source},
- {"help", "List shell built-in commands", "help", builtin_help},
- {NULL, NULL, NULL, NULL}
+ {"env", "Print all environment variables", builtin_env},
+ {"pwd", "Print current directory", builtin_pwd},
+#ifdef BB_FEATURE_SH_IF_EXPRESSIONS
+ {"if", NULL, builtin_if},
+ {"then", NULL, builtin_then},
+ {"else", NULL, builtin_else},
+ {"fi", NULL, builtin_fi},
+#endif
+ {".", "Source-in and run commands in a file", builtin_source},
+ {"help", "List shell built-in commands", builtin_help},
+ {NULL, NULL, NULL}
};
static char *prompt = "# ";
static char *cwd;
static char *local_pending_command = NULL;
+static char *promptStr = NULL;
+static struct jobSet jobList = { NULL, NULL };
#ifdef BB_FEATURE_SH_COMMAND_EDITING
void win_changed(int junk)
@@ -256,9 +279,13 @@ static int builtin_help(struct job *dummy, struct jobSet *junk)
fprintf(stdout, "\nBuilt-in commands:\n");
fprintf(stdout, "-------------------\n");
for (x = bltins; x->cmd; x++) {
+ if (x->descr==NULL)
+ continue;
fprintf(stdout, "%s\t%s\n", x->cmd, x->descr);
}
for (x = bltins_forking; x->cmd; x++) {
+ if (x->descr==NULL)
+ continue;
fprintf(stdout, "%s\t%s\n", x->cmd, x->descr);
}
fprintf(stdout, "\n\n");
@@ -339,6 +366,44 @@ static int builtin_read(struct job *cmd, struct jobSet *junk)
return (res);
}
+#ifdef BB_FEATURE_SH_IF_EXPRESSIONS
+/* Built-in handler for 'if' commands */
+static int builtin_if(struct job *cmd, struct jobSet *junk)
+{
+ cmd->jobContext |= IF_EXP_CONTEXT;
+ printf("Hit an if -- jobContext=%d\n", cmd->jobContext);
+ return TRUE;
+}
+
+/* Built-in handler for 'then' (part of the 'if' command) */
+static int builtin_then(struct job *cmd, struct jobSet *junk)
+{
+ if (cmd->jobContext & IF_EXP_CONTEXT) {
+ fprintf(stderr, "unexpected token `then'\n");
+ fflush(stderr);
+ return FALSE;
+ }
+ cmd->jobContext |= THEN_EXP_CONTEXT;
+ printf("Hit an then -- jobContext=%d\n", cmd->jobContext);
+ return TRUE;
+}
+
+/* Built-in handler for 'else' (part of the 'if' command) */
+static int builtin_else(struct job *cmd, struct jobSet *junk)
+{
+ printf("Hit an else\n");
+ cmd->jobContext |= ELSE_EXP_CONTEXT;
+ return TRUE;
+}
+
+/* Built-in handler for 'fi' (part of the 'if' command) */
+static int builtin_fi(struct job *cmd, struct jobSet *junk)
+{
+ printf("Hit an fi\n");
+ return TRUE;
+}
+#endif
+
/* Built-in '.' handler (read-in and execute commands from file) */
static int builtin_source(struct job *cmd, struct jobSet *junk)
{
@@ -471,7 +536,6 @@ static int getCommand(FILE * source, char *command)
if (source == stdin) {
#ifdef BB_FEATURE_SH_COMMAND_EDITING
int len;
- char *promptStr;
len=fprintf(stdout, "%s %s", cwd, prompt);
fflush(stdout);
promptStr=(char*)xmalloc(sizeof(char)*(len+1));
@@ -587,8 +651,9 @@ static int parseCommand(char **commandPtr, struct job *job, struct jobSet *jobLi
Getting clean memory relieves us of the task of NULL
terminating things and makes the rest of this look a bit
cleaner (though it is, admittedly, a tad less efficient) */
- job->cmdBuf = command = calloc(1, 2*strlen(*commandPtr) + 1);
+ job->cmdBuf = command = calloc(2*strlen(*commandPtr) + 1, sizeof(char));
job->text = NULL;
+ job->jobContext = REGULAR_JOB_CONTEXT;
prog = job->progs;
prog->numRedirections = 0;
@@ -863,7 +928,7 @@ static int parseCommand(char **commandPtr, struct job *job, struct jobSet *jobLi
static int runCommand(struct job *newJob, struct jobSet *jobList, int inBg, int outPipe[2])
{
- struct job *job;
+ struct job *theJob;
int i;
int nextin, nextout;
int pipefds[2]; /* pipefd[0] is for reading */
@@ -957,33 +1022,33 @@ static int runCommand(struct job *newJob, struct jobSet *jobList, int inBg, int
newJob->pgrp = newJob->progs[0].pid;
- /* find the ID for the job to use */
+ /* find the ID for the theJob to use */
newJob->jobId = 1;
- for (job = jobList->head; job; job = job->next)
- if (job->jobId >= newJob->jobId)
- newJob->jobId = job->jobId + 1;
+ for (theJob = jobList->head; theJob; theJob = theJob->next)
+ if (theJob->jobId >= newJob->jobId)
+ newJob->jobId = theJob->jobId + 1;
- /* add the job to the list of running jobs */
+ /* add the theJob to the list of running jobs */
if (!jobList->head) {
- job = jobList->head = malloc(sizeof(*job));
+ theJob = jobList->head = malloc(sizeof(*theJob));
} else {
- for (job = jobList->head; job->next; job = job->next);
- job->next = malloc(sizeof(*job));
- job = job->next;
+ for (theJob = jobList->head; theJob->next; theJob = theJob->next);
+ theJob->next = malloc(sizeof(*theJob));
+ theJob = theJob->next;
}
- *job = *newJob;
- job->next = NULL;
- job->runningProgs = job->numProgs;
- job->stoppedProgs = 0;
+ *theJob = *newJob;
+ theJob->next = NULL;
+ theJob->runningProgs = theJob->numProgs;
+ theJob->stoppedProgs = 0;
if (inBg) {
- /* we don't wait for background jobs to return -- append it
- to the list of backgrounded jobs and leave it alone */
- printf("[%d] %d\n", job->jobId,
+ /* we don't wait for background theJobs to return -- append it
+ to the list of backgrounded theJobs and leave it alone */
+ printf("[%d] %d\n", theJob->jobId,
newJob->progs[newJob->numProgs - 1].pid);
} else {
- jobList->fg = job;
+ jobList->fg = theJob;
/* move the new process group into the foreground */
/* suppress messages when run from /linuxrc mag@sysgo.de */
@@ -1037,7 +1102,6 @@ static int busy_loop(FILE * input)
{
char *command;
char *nextCommand = NULL;
- struct jobSet jobList = { NULL, NULL };
struct job newJob;
pid_t parent_pgrp;
int i;
@@ -1070,7 +1134,8 @@ static int busy_loop(FILE * input)
newJob.numProgs) {
int pipefds[2] = {-1,-1};
runCommand(&newJob, &jobList, inBg, pipefds);
- } else {
+ }
+ else {
free(command);
command = (char *) calloc(BUFSIZ, sizeof(char));
nextCommand = NULL;
@@ -1079,7 +1144,7 @@ static int busy_loop(FILE * input)
/* a job is running in the foreground; wait for it */
i = 0;
while (!jobList.fg->progs[i].pid ||
- jobList.fg->progs[i].isStopped) i++;
+ jobList.fg->progs[i].isStopped == 1) i++;
waitpid(jobList.fg->progs[i].pid, &status, WUNTRACED);
@@ -1128,6 +1193,22 @@ static int busy_loop(FILE * input)
}
+#ifdef BB_FEATURE_CLEAN_UP
+void free_memory(void)
+{
+ if (promptStr)
+ free(promptStr);
+ if (cwd)
+ free(cwd);
+ if (local_pending_command)
+ free(local_pending_command);
+
+ if (jobList.fg && !jobList.fg->runningProgs) {
+ removeJob(&jobList, jobList.fg);
+ }
+}
+#endif
+
int shell_main(int argc, char **argv)
{
@@ -1137,6 +1218,10 @@ int shell_main(int argc, char **argv)
cwd=(char*)xmalloc(sizeof(char)*MAX_LINE+1);
getcwd(cwd, sizeof(char)*MAX_LINE);
+#ifdef BB_FEATURE_CLEAN_UP
+ atexit(free_memory);
+#endif
+
#ifdef BB_FEATURE_SH_COMMAND_EDITING
cmdedit_init();
signal(SIGWINCH, win_changed);
generated by cgit v1.1 at 2024-12-28 17:40:42 +0000