projects / unix-history / blame
| Commit | Line | Data |
|---|---|---|
| ac39d190 C |
1 | #include <setjmp.h> |
| 2 | #include <signal.h> | |
| 3 | #include "rc.h" | |
| 4 | #include "jbwrap.h" | |
| 5 | ||
| 6 | /* | |
| 7 | A return goes back stack frames to the last return. A break does | |
| 8 | not. A signal goes to the last interactive level. (see below) | |
| 9 | */ | |
| 10 | ||
| 11 | bool nl_on_intr = TRUE; | |
| 12 | ||
| 13 | static Estack *estack; | |
| 14 | ||
| 15 | /* add an exception to the input stack. */ | |
| 16 | ||
| 17 | extern void except(ecodes e, Edata data, Estack *ex) { | |
| 18 | ex->prev = estack; | |
| 19 | estack = ex; | |
| 20 | estack->e = e; | |
| 21 | estack->data = data; | |
| 22 | if (e == eError || e == eBreak || e == eReturn) | |
| 23 | estack->interactive = interactive; | |
| 24 | } | |
| 25 | ||
| 26 | /* remove an exception, restore last interactive value */ | |
| 27 | ||
| 28 | extern void unexcept() { | |
| 29 | switch (estack->e) { | |
| 30 | default: | |
| 31 | break; | |
| 32 | case eError: | |
| 33 | interactive = estack->interactive; | |
| 34 | break; | |
| 35 | case eArena: | |
| 36 | restoreblock(estack->data.b); | |
| 37 | break; | |
| 38 | case eFifo: | |
| 39 | unlink(estack->data.name); | |
| 40 | break; | |
| 41 | case eFd: | |
| 42 | close(estack->data.fd); | |
| 43 | break; | |
| 44 | } | |
| 45 | estack = estack->prev; | |
| 46 | } | |
| 47 | ||
| 48 | /* | |
| 49 | Raise an exception. The rules are pretty complicated: you can return | |
| 50 | from a loop inside a function, but you can't break from a function | |
| 51 | inside of a loop. On errors, rc_raise() goes back to the LAST | |
| 52 | INTERACTIVE stack frame. If no such frame exists, then rc_raise() | |
| 53 | exits the shell. This is what happens, say, when there is a syntax | |
| 54 | error in a noninteractive shell script. While traversing the | |
| 55 | exception stack backwards, rc_raise() also removes input sources | |
| 56 | (closing file-descriptors, etc.) and pops instances of variables | |
| 57 | that have been pushed onto the variable stack (e.g., for a function | |
| 58 | call (for $*) or a local assignment). | |
| 59 | */ | |
| 60 | ||
| 61 | extern void rc_raise(ecodes e) { | |
| 62 | if (e == eError && rc_pid != getpid()) | |
| 63 | exit(1); /* child processes exit on an error/signal */ | |
| 64 | for (; estack != NULL; estack = estack->prev) | |
| 65 | if (estack->e != e) { | |
| 66 | if (e == eBreak && estack->e != eArena) | |
| 67 | rc_error("break outside of loop"); | |
| 68 | else if (e == eReturn && estack->e == eError) /* can return from loops inside functions */ | |
| 69 | rc_error("return outside of function"); | |
| 70 | switch (estack->e) { | |
| 71 | default: | |
| 72 | break; | |
| 73 | case eVarstack: | |
| 74 | varrm(estack->data.name, TRUE); | |
| 75 | break; | |
| 76 | case eArena: | |
| 77 | restoreblock(estack->data.b); | |
| 78 | break; | |
| 79 | case eFifo: | |
| 80 | unlink(estack->data.name); | |
| 81 | break; | |
| 82 | case eFd: | |
| 83 | close(estack->data.fd); | |
| 84 | break; | |
| 85 | } | |
| 86 | } else { | |
| 87 | if (e == eError && !estack->interactive) { | |
| 88 | popinput(); | |
| 89 | } else { | |
| 90 | Jbwrap *j = estack->data.jb; | |
| 91 | ||
| 92 | interactive = estack->interactive; | |
| 93 | estack = estack->prev; | |
| 94 | longjmp(j->j, 1); | |
| 95 | } | |
| 96 | } | |
| 97 | rc_exit(1); /* top of exception stack */ | |
| 98 | } | |
| 99 | ||
| 100 | extern bool outstanding_cmdarg() { | |
| 101 | return estack->e == eFifo || estack->e == eFd; | |
| 102 | } | |
| 103 | ||
| 104 | extern void pop_cmdarg(bool remove) { | |
| 105 | for (; estack != NULL; estack = estack->prev) | |
| 106 | switch (estack->e) { | |
| 107 | case eFifo: | |
| 108 | if (remove) | |
| 109 | unlink(estack->data.name); | |
| 110 | break; | |
| 111 | case eFd: | |
| 112 | if (remove) | |
| 113 | close(estack->data.fd); | |
| 114 | break; | |
| 115 | default: | |
| 116 | return; | |
| 117 | } | |
| 118 | } | |
| 119 | ||
| 120 | /* exception handlers */ | |
| 121 | ||
| 122 | extern void rc_error(char *s) { | |
| 123 | pr_error(s); | |
| 124 | set(FALSE); | |
| 125 | redirq = NULL; | |
| 126 | cond = FALSE; /* no longer inside conditional */ | |
| 127 | rc_raise(eError); | |
| 128 | } | |
| 129 | ||
| 130 | extern void sigint(int s) { | |
| 131 | if (s != SIGINT) | |
| 132 | panic("s != SIGINT in sigint catcher"); | |
| 133 | /* this is the newline you see when you hit ^C while typing a command */ | |
| 134 | if (nl_on_intr) | |
| 135 | fprint(2, "\n"); | |
| 136 | nl_on_intr = TRUE; | |
| 137 | redirq = NULL; | |
| 138 | cond = FALSE; | |
| 139 | rc_raise(eError); | |
| 140 | } |