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Commit 88b1abb

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added task 1
1 parent 81fe026 commit 88b1abb

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4 files changed

+160
-4
lines changed

4 files changed

+160
-4
lines changed

‎0x0b-strace/EYNTK/ex_2‎

-11.1 KB
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‎0x0b-strace/Makefile‎

Lines changed: 14 additions & 3 deletions
Original file line numberDiff line numberDiff line change
@@ -8,6 +8,13 @@ SRC = $(patsubst %,$(SDIR)/%,$(_SRC))
88
_OBJ = $(_SRC:.c=.o)
99
OBJECTS = $(patsubst %,$(ODIR)/%,$(_OBJ))
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_SRC1 = strace_1.c
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SRC1 = $(patsubst %,$(SDIR)/%,$(_SRC1))
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_OBJ1 = $(_SRC1:.c=.o)
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OBJECTS1 = $(patsubst %,$(ODIR)/%,$(_OBJ1))
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_DEPS = strace.h
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DEPS = $(patsubst %,$(IDIR)/%,$(_DEPS))
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@@ -16,18 +23,22 @@ SDIR = ./src
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ODIR = .
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OUTPUT = strace_0
26+
OUTPUT1 = strace_1
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$(ODIR)/%.o : $(SDIR)/%.c
2129
$(CC) $(CFLAGS) -c -o $@ $< -I$(IDIR)
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23-
all : $(OUTPUT)
31+
all : $(OUTPUT)$(OUTPUT1)
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$(OUTPUT) : $(OBJECTS)
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$(CC) -o $@ $^ $(LINKS)
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$(OUTPUT1) : $(OBJECTS1)
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$(CC) -o $@ $^ $(LINKS)
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.PHONY : clean
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clean :
31-
rm -f $(OUTPUT) $(OBJECTS)
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rm -f $(OUTPUT) $(OBJECTS)$(OUTPUT1)$(OBJECTS1)
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re: $(OBJ)
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re: $(OBJ)$(OBJ1)

‎0x0b-strace/README.md‎

Lines changed: 54 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -1,7 +1,7 @@
11
# 0x0B. C - Strace
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### System programming & Algorithm ― Linux programming
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4-
* strace_0.c - A program that executes and traces a given command.
4+
* strace_0.c - A program that executes and traces a given command. Each time a syscall is intercepted, it prints its number, followed by a new line
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66
Usage: ./strace_0 command [args...]
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@@ -77,5 +77,58 @@ Holberton
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3
7878
231
7979
$
80+
```
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* strace_1.c - A program that executes and traces a given command. Each time a syscall is intercepted, it prints its name, followed by a new line
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Usage: ./strace_1 command [args...]
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8186
```
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$make strace_1
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[...]
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$./strace_1 /bin/echo Holberton
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execve
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brk
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access
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mmap
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access
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open
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fstat
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mmap
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close
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access
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open
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read
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fstat
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mmap
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mprotect
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mmap
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mmap
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close
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mmap
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mmap
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arch_prctl
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mprotect
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mprotect
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mprotect
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munmap
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brk
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brk
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open
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fstat
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mmap
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close
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fstat
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mmap
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write
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Holberton
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close
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munmap
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close
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exit_group
129+
$
130+
```
131+
132+
## Resources:
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134+
* [syscalls](https://filippo.io/linux-syscall-table/)

‎0x0b-strace/src/strace_1.c‎

Lines changed: 92 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,92 @@
1+
#include "strace.h"
2+
3+
/**
4+
* run_tracee - A function that runs a tracee
5+
* @argv: Has path and arguments to be executed
6+
* @envp: environment variables
7+
*/
8+
void run_tracee(char *const argv[], char *const envp[])
9+
{
10+
if (ptrace(PTRACE_TRACEME, 0, 0, 0) < 0)
11+
{
12+
perror("Error setting TRACEME");
13+
exit(EXIT_FAILURE);
14+
}
15+
kill(getpid(), SIGSTOP);
16+
execve(argv[0], argv, envp);
17+
}
18+
19+
/**
20+
* wait_for_syscall - A function that traps only syscalls
21+
* @child_pid: pid of the tracee to be traced
22+
* Return: 1 if syscall is trapped else 0
23+
*/
24+
int wait_for_syscall(pid_t child_pid)
25+
{
26+
int status;
27+
28+
while (1)
29+
{
30+
ptrace(PTRACE_SYSCALL, child_pid, 0, 0);
31+
waitpid(child_pid, &status, 0);
32+
if (WIFSTOPPED(status) && WSTOPSIG(status) & 0x80)
33+
return (0);
34+
if (WIFEXITED(status))
35+
return (1);
36+
}
37+
}
38+
39+
/**
40+
* run_tracer - A function that runs a tracer
41+
* @child_pid: pid of the tracee to be traced
42+
*/
43+
void run_tracer(pid_t child_pid)
44+
{
45+
int status;
46+
struct user_regs_struct regs;
47+
48+
waitpid(child_pid, &status, 0);
49+
ptrace(PTRACE_SETOPTIONS, child_pid, 0, PTRACE_O_TRACESYSGOOD);
50+
while (1)
51+
{
52+
if (wait_for_syscall(child_pid) != 0)
53+
break;
54+
ptrace(PTRACE_GETREGS, child_pid, 0, &regs);
55+
printf("%s", syscalls_64_g[(size_t) regs.orig_rax].name);
56+
fflush(stdout);
57+
printf("\n");
58+
if (wait_for_syscall(child_pid) != 0)
59+
break;
60+
}
61+
}
62+
63+
/**
64+
* main - Starts the program
65+
* @argc : no of command line arguments
66+
* @argv: command line arguments
67+
* @envp: environment variables
68+
* Return: on success - EXIT_SUCCESS, on failure - EXIT_FAILURE
69+
*/
70+
int main(int argc, char *const argv[], char *const envp[])
71+
{
72+
pid_t child_pid;
73+
74+
if (argc < 2)
75+
printf("Usage: %s command [args...]\n", argv[0]);
76+
else
77+
{
78+
child_pid = fork();
79+
if (child_pid == 0)
80+
{
81+
run_tracee(argv + 1, envp);
82+
} else if (child_pid > 0)
83+
{
84+
run_tracer(child_pid);
85+
} else
86+
{
87+
perror("fork failed");
88+
exit(EXIT_FAILURE);
89+
}
90+
}
91+
return (EXIT_SUCCESS);
92+
}

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