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diff --git a/static/v10/man2/exec.2 b/static/v10/man2/exec.2 new file mode 100644 index 00000000..7c1d013f --- /dev/null +++ b/static/v10/man2/exec.2 @@ -0,0 +1,288 @@ +.TH EXEC 2 +.CT 2 proc_man +.SH NAME +execl, execv, execle, execve, execlp, execvp, exect, environ \(mi execute a file +.SH SYNOPSIS +.nf +.B int "execl(name, arg0, arg1, ..., argn, (char *)0)" +.B char *name, *arg0, *arg1, ..., *argn; +.PP +.B int execv(name, argv) +.B char *name, *argv[]; +.PP +.B "int execle(name, arg0, arg1, ..., argn, (char *)0, envp)" +.B "char *name, *arg0, *arg1, ..., *argn, *envp[];" +.PP +.B int execve(name, argv, envp) +.B char *name, *argv[], *envp[]; +.PP +.B int "execlp(name, arg0, arg1, ..., argn, (char *)0)" +.B char *name, *arg0, *arg1, ..., *argn; +.PP +.B int execvp(name, argv) +.B char *name, *argv[]; +.PP +.B int exect(name, argv, envp) +.B char *name, *argv[], *envp[]; +.PP +.B extern char **environ; +.fi +.SH DESCRIPTION +.I Exec +in all its forms +overlays the calling process with the named file, then +transfers to the +entry point of the image of the file. +There can be no return from a successful +.IR exec ; +the calling image is lost. +.PP +Files remain open across +.I exec +unless explicit arrangement has been made; +see +.IR ioctl (2). +Signals that are caught (see +.IR signal (2)) +are reset +to their default values. +Other signals' behavior is unchanged. +.PP +Each user has a +.I real +userid and groupid and an +.I effective +userid and groupid. +The real userid (groupid) +identifies the person using the system; +the effective userid (groupid) +determines access privileges. +.I Exec +changes the effective userid and groupid to +the owner of the executed file if the file has the set-userid +or set-groupid modes. +The real userid is not affected. +.PP +The security label (see +.IR getflab (2)) +of the process is set as follows. +If any arguments or environment parameters are present, +or if and file descriptor numbers greater than 3 are in use, +the lattice value of the process label +is ascribed to them, otherwise lattice bottom. +This value is ORed with the lattice value of +the executed file to obtain the new lattice value for the process. +If the new lattice value does not dominate the old,รย +the permission mask (see +.IR umask (2)) +is set to 022. +.PP +Process licenses persist. +In the simplest case, the process obtains from the +file the capabilities +for which the process has licenses; see +.IR getplab (2). +The detailed computation for process capabilities is: +Nominal capabilities are determined +by ANDing the file capabilities with the +capabilities in the file system ceiling (see +.IR mount (2)) +and then ORing with built-in minima. +Nominal licenses are determined by ANDing the file licenses +with the licenses in the file system +ceiling and with built-in maxima. +Process capabilities are set by ORing the +process licenses with the nominal licenses, then ANDing +with the nominal capabilities. +.PP +The builtin minimum file capabilities are all 0. +The builtin maximum file licenses for +.B T_SETPRIV +and +.B T_LOG +are 0; the rest are 1. +.B +.PP +The +.I name +argument +is a pointer to the name of the file +to be executed. +If the first two bytes of that file are the ASCII +characters +.LR #! , +then the first line of the file is taken to be ASCII and +determines the name of the program to execute. +The first nonblank string following +.L #! +in that line is substituted for +.I name. +Any second string, separated from the first by blanks or tabs, +is inserted between +the first two arguments (arguments 0 and 1) passed to the invoked file. +.PP +The argument pointers +.I arg0, arg1, ... +or the pointers in +.I argv +address null-terminated strings. +Conventionally argument 0 +is the name of the +file. +.PP +.I Execl +is useful when a known file with known arguments is +being called; +the arguments to +.I execl +are the character strings +constituting the file and the arguments. +.PP +.I Execv +is useful when the number of arguments is unknown +in advance; +the arguments to +.I execv +are the name of the file to be +executed and a vector of strings containing +the arguments. +The last argument string must be followed +by a 0 +pointer. +.PP +When a C program is executed, +it is called as follows: +.IP +.EX +main(argc, argv, envp) +int argc; +char **argv, **envp; +.EE +.PP +where +.IR argc "" +is the argument count +and +.IR argv "" +is an array of character pointers +to the arguments themselves. +Conventionally +.I argc +is at least 1 +and +.B argv[0] +points to +the name of the file. +.PP +.I Argv +is directly usable in another +.I execv +because +.BR argv[argc]==0 . +.PP +.I Envp +is a pointer to an array of strings that constitute +the +.I environment +of the process. +Each string conventionally consists of a name, an +.LR = , +and a null-terminated value; +or a name, a pair of parentheses +.LR (), +a value bracketed by +.L { +and +.LR } , +and a null character. +The array of pointers is terminated by a null pointer. +The shell +.IR sh (1) +passes an environment entry for each global shell variable +defined when the program is called. +See +.IR environ (5) +for some conventionally +used names. +.PP +The C run-time start-off routine places a copy of +.I envp +in the global cell +.I environ, +which is used +by +.I execv +and +.I execl +to pass the environment to any subprograms executed by the +current program. +The +.I exec +routines use lower-level routines as follows +to pass an environment explicitly: +.IP +.nf +\fLexecve(file, argv, environ); +execle(file, arg0, arg1, . . . , argn, (char *)0, environ);\fP +.fi +.PP +.I Execlp +and +.I execvp +are called with the same arguments as +.I execl +and +.I execv, +but duplicate the shell's actions in searching for an executable +file in a list of directories given in the +.B PATH +environment variable. +.PP +.I Exect +is the same as +.I execve, +except it arranges for a stop to occur on the first instruction +of the new core image for the benefit of tracers, see +.IR proc (4). +.SH FILES +.TF /bin/sh +.TP +.F /bin/sh +shell, invoked if command file found +by +.I execlp +or +.I execvp +.SH "SEE ALSO" +.IR fork (2), +.IR environ (5) +.SH DIAGNOSTICS +.BR E2BIG , +.BR EACCES , +.BR EFAULT , +.BR EIO , +.BR ELAB , +.BR ELOOP , +.BR ENOENT , +.BR ENOEXEC , +.BR ENOMEM , +.BR ENOTDIR , +.BR ENXIO , +.BR EROFS , +.BR ETXTBSY +.SH BUGS +If +.I execvp +is called to execute a file that turns out to be a shell +command file, +and if it is impossible to execute the shell, +some of the values in +.I argv +may be modified before return. +.br +The path search of +.I execlp +and +.I execvp +does not extend to names substituted by +.LR #! 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