From 74a4fe3270886cdd47a0e50c2426426a78e357df Mon Sep 17 00:00:00 2001 From: Mark Kettenis Date: Thu, 30 Sep 2004 20:15:39 +0000 Subject: [PATCH] * fork-child.c: Update copyright year. Fix coding style. --- gdb/ChangeLog | 4 ++ gdb/fork-child.c | 203 +++++++++++++++++++++++++++---------------------------- 2 files changed, 103 insertions(+), 104 deletions(-) diff --git a/gdb/ChangeLog b/gdb/ChangeLog index 4c5a42c..c6c8da2 100644 --- a/gdb/ChangeLog +++ b/gdb/ChangeLog @@ -1,3 +1,7 @@ +2004-09-30 Mark Kettenis + + * fork-child.c: Update copyright year. Fix coding style. + 2004-09-29 Mark Kettenis * defs.h (msavestring, mstrsave): Remove prototypes. diff --git a/gdb/fork-child.c b/gdb/fork-child.c index e1d32b0..90580ba 100644 --- a/gdb/fork-child.c +++ b/gdb/fork-child.c @@ -1,6 +1,8 @@ /* Fork a Unix child process, and set up to debug it, for GDB. - Copyright 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1998, 1999, 2000, - 2001 Free Software Foundation, Inc. + + Copyright 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1998, 1999, + 2000, 2001, 2004 Free Software Foundation, Inc. + Contributed by Cygnus Support. This file is part of GDB. @@ -34,19 +36,18 @@ #include -/* This just gets used as a default if we can't find SHELL */ +/* This just gets used as a default if we can't find SHELL. */ #ifndef SHELL_FILE #define SHELL_FILE "/bin/sh" #endif extern char **environ; -/* This function breaks up an argument string into an argument - * vector suitable for passing to execvp(). - * E.g., on "run a b c d" this routine would get as input - * the string "a b c d", and as output it would fill in argv with - * the four arguments "a", "b", "c", "d". - */ +/* Break up SCRATCH into an argument vector suitable for passing to + execvp and store it in ARGV. E.g., on "run a b c d" this routine + would get as input the string "a b c d", and as output it would + fill in ARGV with the four arguments "a", "b", "c", "d". */ + static void breakup_args (char *scratch, char **argv) { @@ -54,49 +55,45 @@ breakup_args (char *scratch, char **argv) for (;;) { - /* Scan past leading separators */ while (*cp == ' ' || *cp == '\t' || *cp == '\n') - { - cp++; - } + cp++; - /* Break if at end of string */ + /* Break if at end of string. */ if (*cp == '\0') break; - /* Take an arg */ + /* Take an arg. */ *argv++ = cp; - /* Scan for next arg separator */ + /* Scan for next arg separator. */ cp = strchr (cp, ' '); if (cp == NULL) cp = strchr (cp, '\t'); if (cp == NULL) cp = strchr (cp, '\n'); - /* No separators => end of string => break */ + /* No separators => end of string => break. */ if (cp == NULL) break; - /* Replace the separator with a terminator */ + /* Replace the separator with a terminator. */ *cp++ = '\0'; } - /* execv requires a null-terminated arg vector */ + /* Null-terminate the vector. */ *argv = NULL; - } -/* When executing a command under the given shell, return non-zero - if the '!' character should be escaped when embedded in a quoted +/* When executing a command under the given shell, return non-zero if + the '!' character should be escaped when embedded in a quoted command-line argument. */ static int escape_bang_in_quoted_argument (const char *shell_file) { const int shell_file_len = strlen (shell_file); - + /* Bang should be escaped only in C Shells. For now, simply check that the shell name ends with 'csh', which covers at least csh and tcsh. This should be good enough for now. */ @@ -112,14 +109,14 @@ escape_bang_in_quoted_argument (const char *shell_file) return 0; } -/* Start an inferior Unix child process and sets inferior_ptid to its pid. - EXEC_FILE is the file to run. - ALLARGS is a string containing the arguments to the program. - ENV is the environment vector to pass. SHELL_FILE is the shell file, - or NULL if we should pick one. Errors reported with error(). */ +/* Start an inferior Unix child process and sets inferior_ptid to its + pid. EXEC_FILE is the file to run. ALLARGS is a string containing + the arguments to the program. ENV is the environment vector to + pass. SHELL_FILE is the shell file, or NULL if we should pick + one. */ -/* This function is NOT-REENTRANT. Some of the variables have been - made static to ensure that they survive the vfork() call. */ +/* This function is NOT reentrant. Some of the variables have been + made static to ensure that they survive the vfork call. */ void fork_inferior (char *exec_file_arg, char *allargs, char **env, @@ -141,20 +138,19 @@ fork_inferior (char *exec_file_arg, char *allargs, char **env, int shell = 0; static char **argv; - /* If no exec file handed to us, get it from the exec-file command -- with - a good, common error message if none is specified. */ + /* If no exec file handed to us, get it from the exec-file command + -- with a good, common error message if none is specified. */ exec_file = exec_file_arg; if (exec_file == 0) exec_file = get_exec_file (1); - /* STARTUP_WITH_SHELL is defined in inferior.h. - * If 0, we'll just do a fork/exec, no shell, so don't - * bother figuring out what shell. - */ + /* STARTUP_WITH_SHELL is defined in inferior.h. If 0,e we'll just + do a fork/exec, no shell, so don't bother figuring out what + shell. */ shell_file = shell_file_arg; if (STARTUP_WITH_SHELL) { - /* Figure out what shell to start up the user program under. */ + /* Figure out what shell to start up the user program under. */ if (shell_file == NULL) shell_file = getenv ("SHELL"); if (shell_file == NULL) @@ -162,9 +158,9 @@ fork_inferior (char *exec_file_arg, char *allargs, char **env, shell = 1; } - /* Multiplying the length of exec_file by 4 is to account for the fact - that it may expand when quoted; it is a worst-case number based on - every character being '. */ + /* Multiplying the length of exec_file by 4 is to account for the + fact that it may expand when quoted; it is a worst-case number + based on every character being '. */ len = 5 + 4 * strlen (exec_file) + 1 + strlen (allargs) + 1 + /*slop */ 12; /* If desired, concat something onto the front of ALLARGS. SHELL_COMMAND is the result. */ @@ -178,17 +174,18 @@ fork_inferior (char *exec_file_arg, char *allargs, char **env, if (!shell) { - /* We're going to call execvp. Create argv */ - /* Largest case: every other character is a separate arg */ - argv = (char **) xmalloc (((strlen (allargs) + 1) / (unsigned) 2 + 2) * sizeof (*argv)); + /* We're going to call execvp. Create argument vector. + Calculate an upper bound on the length of the vector by + assuming that every other character is a separate + argument. */ + int argc = (strlen (allargs) + 1) / 2 + 2; + argv = (char **) xmalloc (argc * sizeof (*argv)); argv[0] = exec_file; breakup_args (allargs, &argv[1]); - } else { - - /* We're going to call a shell */ + /* We're going to call a shell. */ /* Now add exec_file, quoting as necessary. */ @@ -198,9 +195,9 @@ fork_inferior (char *exec_file_arg, char *allargs, char **env, strcat (shell_command, "exec "); - /* Quoting in this style is said to work with all shells. But csh - on IRIX 4.0.1 can't deal with it. So we only quote it if we need - to. */ + /* Quoting in this style is said to work with all shells. But + csh on IRIX 4.0.1 can't deal with it. So we only quote it if + we need to. */ p = exec_file; while (1) { @@ -251,32 +248,29 @@ fork_inferior (char *exec_file_arg, char *allargs, char **env, strcat (shell_command, " "); strcat (shell_command, allargs); - } - /* exec is said to fail if the executable is open. */ + /* On some systems an exec will fail if the executable is open. */ close_exec_file (); /* Retain a copy of our environment variables, since the child will - replace the value of environ and if we're vforked, we have to + replace the value of environ and if we're vforked, we have to restore it. */ save_our_env = environ; /* Tell the terminal handling subsystem what tty we plan to run on; it will just record the information for later. */ - new_tty_prefork (inferior_io_terminal); /* It is generally good practice to flush any possible pending stdio - output prior to doing a fork, to avoid the possibility of both the - parent and child flushing the same data after the fork. */ - + output prior to doing a fork, to avoid the possibility of both + the parent and child flushing the same data after the fork. */ gdb_flush (gdb_stdout); gdb_flush (gdb_stderr); - /* If there's any initialization of the target layers that must happen - to prepare to handle the child we're about fork, do it now... - */ + /* If there's any initialization of the target layers that must + happen to prepare to handle the child we're about fork, do it + now... */ if (pre_trace_fun != NULL) (*pre_trace_fun) (); @@ -301,9 +295,9 @@ fork_inferior (char *exec_file_arg, char *allargs, char **env, if (debug_setpgrp == -1) perror ("setpgrp failed in child"); - /* Ask the tty subsystem to switch to the one we specified earlier - (or to share the current terminal, if none was specified). */ - + /* Ask the tty subsystem to switch to the one we specified + earlier (or to share the current terminal, if none was + specified). */ new_tty (); /* Changing the signal handlers for the inferior after @@ -314,14 +308,15 @@ fork_inferior (char *exec_file_arg, char *allargs, char **env, /* "Trace me, Dr. Memory!" */ (*traceme_fun) (); + /* The call above set this process (the "child") as debuggable - * by the original gdb process (the "parent"). Since processes - * (unlike people) can have only one parent, if you are - * debugging gdb itself (and your debugger is thus _already_ the - * controller/parent for this child), code from here on out - * is undebuggable. Indeed, you probably got an error message - * saying "not parent". Sorry--you'll have to use print statements! - */ + by the original gdb process (the "parent"). Since processes + (unlike people) can have only one parent, if you are debugging + gdb itself (and your debugger is thus _already_ the + controller/parent for this child), code from here on out is + undebuggable. Indeed, you probably got an error message + saying "not parent". Sorry; you'll have to use print + statements! */ /* There is no execlpe call, so we have to set the environment for our child in the global variable. If we've vforked, this @@ -330,19 +325,17 @@ fork_inferior (char *exec_file_arg, char *allargs, char **env, path to find $SHELL. Rich Pixley says so, and I agree. */ environ = env; - /* If we decided above to start up with a shell, - * we exec the shell, - * "-c" says to interpret the next arg as a shell command - * to execute, and this command is "exec ". - * "-f" means "fast startup" to the c-shell, which means - * don't do .cshrc file. Doing .cshrc may cause fork/exec - * events which will confuse debugger start-up code. - */ + /* If we decided above to start up with a shell, we exec the + shell, "-c" says to interpret the next arg as a shell command + to execute, and this command is "exec + ". "-f" means "fast startup" to the c-shell, which + means don't do .cshrc file. Doing .cshrc may cause fork/exec + events which will confuse debugger start-up code. */ if (shell) { execlp (shell_file, shell_file, "-c", shell_command, (char *) 0); - /* If we get here, it's an error */ + /* If we get here, it's an error. */ fprintf_unfiltered (gdb_stderr, "Cannot exec %s: %s.\n", shell_file, safe_strerror (errno)); gdb_flush (gdb_stderr); @@ -350,13 +343,14 @@ fork_inferior (char *exec_file_arg, char *allargs, char **env, } else { - /* Otherwise, we directly exec the target program with execvp. */ + /* Otherwise, we directly exec the target program with + execvp. */ int i; char *errstring; execvp (exec_file, argv); - /* If we get here, it's an error */ + /* If we get here, it's an error. */ errstring = safe_strerror (errno); fprintf_unfiltered (gdb_stderr, "Cannot exec %s ", exec_file); @@ -369,9 +363,10 @@ fork_inferior (char *exec_file_arg, char *allargs, char **env, i++; } fprintf_unfiltered (gdb_stderr, ".\n"); - /* This extra info seems to be useless - fprintf_unfiltered (gdb_stderr, "Got error %s.\n", errstring); - */ +#if 0 + /* This extra info seems to be useless. */ + fprintf_unfiltered (gdb_stderr, "Got error %s.\n", errstring); +#endif gdb_flush (gdb_stderr); _exit (0177); } @@ -382,20 +377,21 @@ fork_inferior (char *exec_file_arg, char *allargs, char **env, init_thread_list (); - inferior_ptid = pid_to_ptid (pid); /* Needed for wait_for_inferior stuff below */ + /* Needed for wait_for_inferior stuff below. */ + inferior_ptid = pid_to_ptid (pid); /* Now that we have a child process, make it our target, and - initialize anything target-vector-specific that needs initializing. */ - + initialize anything target-vector-specific that needs + initializing. */ (*init_trace_fun) (pid); /* We are now in the child process of interest, having exec'd the correct program, and are poised at the first instruction of the new program. */ - /* Allow target dependent code to play with the new process. This might be - used to have target-specific code initialize a variable in the new process - prior to executing the first instruction. */ + /* Allow target dependent code to play with the new process. This + might be used to have target-specific code initialize a variable + in the new process prior to executing the first instruction. */ TARGET_CREATE_INFERIOR_HOOK (pid); #ifdef SOLIB_CREATE_INFERIOR_HOOK @@ -409,18 +405,16 @@ void startup_inferior (int ntraps) { int pending_execs = ntraps; - int terminal_initted; + int terminal_initted = 0; - /* The process was started by the fork that created it, - but it will have stopped one instruction after execing the shell. - Here we must get it up to actual execution of the real program. */ + /* The process was started by the fork that created it, but it will + have stopped one instruction after execing the shell. Here we + must get it up to actual execution of the real program. */ clear_proceed_status (); init_wait_for_inferior (); - terminal_initted = 0; - if (STARTUP_WITH_SHELL) inferior_ignoring_startup_exec_events = ntraps; else @@ -430,13 +424,14 @@ startup_inferior (int ntraps) while (1) { - /* Make wait_for_inferior be quiet */ + /* Make wait_for_inferior be quiet. */ stop_soon = STOP_QUIETLY; wait_for_inferior (); if (stop_signal != TARGET_SIGNAL_TRAP) { - /* Let shell child handle its own signals in its own way */ - /* FIXME, what if child has exit()ed? Must exit loop somehow */ + /* Let shell child handle its own signals in its own way. + FIXME: what if child has exited? Must exit loop + somehow. */ resume (0, stop_signal); } else @@ -444,9 +439,10 @@ startup_inferior (int ntraps) /* We handle SIGTRAP, however; it means child did an exec. */ if (!terminal_initted) { - /* Now that the child has exec'd we know it has already set its - process group. On POSIX systems, tcsetpgrp will fail with - EPERM if we try it before the child's setpgid. */ + /* Now that the child has exec'd we know it has already + set its process group. On POSIX systems, tcsetpgrp + will fail with EPERM if we try it before the child's + setpgid. */ /* Set up the "saved terminal modes" of the inferior based on what modes we are starting it with. */ @@ -458,11 +454,10 @@ startup_inferior (int ntraps) terminal_initted = 1; } - pending_execs = pending_execs - 1; - if (0 == pending_execs) + if (--pending_execs == 0) break; - resume (0, TARGET_SIGNAL_0); /* Just make it go on */ + resume (0, TARGET_SIGNAL_0); /* Just make it go on. */ } } stop_soon = NO_STOP_QUIETLY; -- 2.7.4